Abran's Psient

‘Te mind is wide than the sky, put them side by side the one the other will contain with ease and you beside.’ Ψ Abran’s Psient

Antheology

Written by those of the Wikipedia -

Compiled, Written and Edited

by Abrademus

polaris 7451369821753 1 Psient Antheology

1 Introduction - page 3 2 Laws & Justice - page 8 3 Miracles - page 16 4 Teology & Religion - page 24 5) Mind -Psychology, Body-Physiology & Soul Philosophy- page 62 6 Science; Biology, Chemistry, Physics & Math - page 167 & 245 7 Technology & Computing - page 268 8 Language & Communication - page 286 9 Society & State page 311 10 Fashion, Art, Design, & Craft - page 391 11 Sound & Music - page 433 12 Sexuality - page 453 13 Nature & Environment - page 478 14 Universe & Cosmology - page 504 15 Astrology, Zodiac & Vortex- page 530 16 Dust & Particles - page 538 17 Light & Crystals - page 542 18 Plants & Chemicals - page 550 19 Food, Drink & Diet - page 560 20 Prayer, Chanting, Meditation - page 570

21 Nerd’s & Afterlife - page 577

Tis document is written in Banoshie, the original name of English.

2 1) Introduction and the Key

Here's an adventure in religious and other theoretical thought from some of the greatest thinkers of all time condensed by writers of the Wikipedia and Abrademus; the writers of the wikipedia are the true genius of this book, Abrademus complied it. Much of which was revealed by God. Psient is antheology that studies people, society and the universe - the subject - individualism, life on planet earth and life within bodies of states of being and and up too heaven. Trough Biological, Chemical and Physical and Psychological, Physiological and Philosophical realms as well as cosmological, astrological and other aspects of human/animal existance. Trough understanding of God. If theology is live; atheology is alive. Tis is part of a religion; but explains life and existence; through though and knowledge, Psient is a master anthesis.

Psi relates to pressure of the body physiology. It is most important to keep auto dynamic pressure at an optimum; this can keep the body healthy. Further, pressure is organs being made from compressed matter physics autodynamonically. Its started as dust through a aulmendrinacal reaction, the body was blinded by light by God for frst occurrence God made a brain then heart them organs then body then sight, taste, smell, hearing them sense then logic. Breaking the law can eﬀect this badly, hence justice is important. As can exercise improve it and sense datum like this book can help infuse it. To be Psient is to keep a good healthy balance in psi.

Key:

Introduction: Healo: How are you?

Te Fundamentals and introduction. 1- Say ‘i believe in you God’ through your inner voice of mind.2- say ‘i believe in you God’ out loud vocally -cords humming and bold - audible! Each aﬀects 1:thought, 2:word, 1 prayer for 3:deed :: - the creed.

1+1=3 (god's law of creation) the frst port of call for family. (man(1) intercourse(operator) woman(1) and made baby(1), total(3) Tere are the living, the dead and the unborn and the god. Earth (1) + (Fire, Wind, Water)3) Earth is 1 as it is a solid and has defnite shape - the 3 others are more like vapour. To Earth and Water(2) are more alike than Wind and Fire(2).

With more essence too par - there are Solids, Liquids, Gases and Plasmas, Air, Umeni and Sound

Tere is also positive, negative and the zero - within the possible. And infnity- unending. Tere are 3 perceptual’s of vision- dark-psi, clear-psi, light-psi intermixed with 1 chroma, Light can only be seen in the darkness and darkness can only be seen in the light + refractions, refections even resemptions - all within 0 the void.

God began by grabbing pheloganirancal matter from Heaven and placed it spinning in the void that makes up the material universes. He can make these every minute and they last for duration 1x7943128659417x769 light years; when the universe is created all the life being that are to live in it ever are also created along with some dummies for extra ploy in creation for the womb to accept challenges from sperm to egg intercourse.

Tere are 3 sites of human conscious of mind, spirit and soul - perceived by consciousness and the cosmos all governed by the 'one creator' - god, (consciousness, cosmos, god) If you are just concentrating on one thing the other is of lesser signifcance, its value can alter one too zero, or can increase to play within the infnitive (+/-). from Perception and Imagination, too reading the grail. Perception is governed by the dialogue between the energy's of the others and the ultimate -god(1)

Tere are the 12 directions and feelings too each; see if you can pick a few of them up in Psient ahead, maybe note some of your own. Remember too call god on everything your unsure of, just ask!; Love is 69 North-West. Tanks be to be god and may god be with you - Peace is NE 37degrees. In god we trust - May god be with you in every direction can you fnd the meaning of the directions by asking god?

3 If love is in equilibrium then one meet's with and becomes fuent in abundance and satisfes loving God. Tis process is driven by wonder and fantasy. And lives by the belly of energy so discussed/given with any other 1(sum,n). Malice can break these processes.

Anything out side of the equilibrium can aﬀect harshly human psychology, physiology or philosophy - mind/body/soul and if not of equality the measure can possibly upset - If you don’t understand it. Trough argument/understanding and discussion- Subjects can reach "Psion" where the vision between matches up and becomes a formal reality - within any given view of perception, a formal understanding is reached - you are at one with God and his people.

At best Harmonic grace - A given good + in terms of in-formation/knowledge can make 'things' within a perceptual or imaginative sense - via the crown (of creativity) - wisdom (highest forms of thought and creation)- any defnite knowledge. Tus forming - A sense based datum.

Te Psage works 'all as one' and can understand reality eﬀectively- to create and curate, in each book the Psage can discover information and knowledge that interweive the chapter’s that correlate to experiencing of life to the fullest, this key helps mix that knowledge. Psient is a holisitic education. Te book build's the readers knowledge up bit by bit and this key help mix and blend that knowledge and cross-reference it in a way that anyone can understand age after age and help build wisdom.

Once you understand the book the otherwise invisible world can be better understood. From heaven to earth (0) to equate sense based perception, into datum (1). from 'the perception and imagination' - from concentration too understanding, deliberating; questioning and answering - God’s favourite - discussion: Word form.

In so doing so a meme is created in the mind-a particle of meta physical thought. Te meme can be transferred through telepathy, telepathy can cross paradigm’s from a universe into heaven and even hell, but only with a tuning/prayer to God. In human's the codes of meme's can alter that can alter RNA genetic patterns though sense registry and transmutation for example a RNA ‘gene’ ‘computes’ the healing of pain via thought to heal and relieve, then transmutes the logic to DNA that can heal the body. ONA Oxygen Nuclic Acid registers toxicity of oxygen molecules and can tell you if the atmosphere is polluted, ONA is a molecule thick. Te real sequence is ONA, RNA then DNA.

Tey act on the vibration of frequencies , wave function -between consciousness and the cosmos, dependant on the 'discussion' and dialogue. thought, word, deed (3). and can alter between meditation (0) and action (1) and each of these all act on the forces of existence (nx). - tho invisibly the other(s) act interdependently and so solely together in equilibrium exponentially with fux through all paradigm’s.

At any given state, the entire equation can be either at 1 at 0 or both in the same instance 'happening/not happening or mediating' possibly between worlds/ engines/realities/paradigms. As life is a combination of all - output can vary between any state - any instance itself, &or along a constant. A ‘state’ of ‘both’ is deliberation only.

With narrative (linear(wave), non-linear(point)) - or seemingly more random. Whether invisible or blatant, imagined or real and or again possibly any entwined. States vary between confusion and clairvoyance via deliberation to defne a defnite answer - through logic, reason and opinion.

Dust begins in the cosmos, highly charged particles fex out dust into the atmosphere. God created us from dust by bonding dust particles with aulmendrenical light.

Te Sun is a 1 whole altered by any combination of 1(*) star systems and the greater uni/multiverse and can be seen through the conscious - astral travel, the discovery of the telescope of your mind. You can make it shine brighter - with more love and intensity, positivity, tho sometimes balance is needed if things are too bright or too dark.

Neverland is afterlife in the cosmos, missing out the creator (god) - no belief.(0) If you don’t believe in God you cannot go to heaven.

You can be near or far or anywhere in-between and/or with/out a sense of direction (0) or follow your heart(1) Out of three days, yesterday, tomorrow - today is the only day you can actually do anything. You are constantly caught up in reading memories, the instance the ‘Now’ and thought's of the future and the now. the word. the rhythm and the melody(3) and then the potent most form of expression, song. Singing is louder if you enjoy it more - Selassie.

Memory is one thing that god gave us that is infnite; just like existence, tho it is gain access too these, as god keeps them for us; you must do the right things for infnite memory. Listen carefully. Tese are called the Akashic records.

4 Te SI base units and their physical quantities are the metre for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for amount of substance.

1 billion seconds is a signifcant birthday or anniversary, being about 4 months shy of 32 years. 1 billion seconds is 31 years, 251 days, 13 hours, 34 minutes, 54.7843 seconds. How will you spend each moment? A Billion Cuneri is 31 Uremuni, 4 Munerim,(36 Tumeir) 19 Aumrei, 7 then 5 a Cuneri is 0.901 secs, that is God’s language for time, the old Zodiac.

Te Key, further discussion:

Tere are subtractive chromas(light (stars and the sun)) and additive chromas(pigment) - Material reality (Paints). Tese are the fundamentals of perception and relate to the imagination as well as fundamental reality - the earth, the universe and heaven. As well as the afterlife.

Te Psage works 'all as one' and uses each topic eﬀectively in discussion with each other- to create and drive over thought, People dissimilar with Psient all play a ‘Part’ in the greater whole of life and reality - they maybe dumb to its notions and discussion but Partists are seen too instill maximum amounts of creative energy upon the Psage, the Psage must educate the Partist. Some may already be Sages of Science, yet not Psages of Psient.

Psient contains mainly information and knowledge and talks of wisdom. Te mind create's memes - particles of thought as the Psage reads, these memes can be transferred by telepathy (inner voice) between beings and can transcend either the living or the dead. And or read for heard. In human's the codes of meme's can alter intelligence and thus they’re environment, Tought, word, deed (3). and can alter between sleep, meditation (0) and action (1) and each of these all act on the forces(n1). - tho invisibly the other(s) act interdependently with fux.

As life in understanding is a combination of all topics, from category to category, for example you may cross reference physiology with biology to understand something in greater depth - output can vary between any state - any instance itself, &or along a constant. With narrative (linear(wave), non-linear(point)) - or seemingly chosen/random and fux. Whether invisible or blatant, imagined or real and or again possibly any entwined. Conscious states vary between confusion and clairvoyance via deliberation to defne a defnite answer - through logic and opinion as understanding of Psient builds.

Tis is known as the gate- the use of which is a portal to anywhere within any topic/dimension through any other topic or reality too reach any state of understanding while comparing and analysing messages between paradigm’s. For example cross referencing how laws of justice relate to physiology and harm and how the body functions if damage occurs; then into prayer where you can learn to heal the body; concepts from math cross over with computing so you can learn to code etc.

Te time system the vortex takes this further for a whole new dialogue with time, every 4 minutes (quarts) the earth turns a degree, there are 360 degrees a day. Te Zodiac is God’s time space measurement system.

What formerly was called death, in Psient is called Nerding (nobody ever really dies). Tis refects the second law of thermodynamics that states that all energy changes from state to state and never really dies.

Psient also looks at language and communication this enables the Psage to frmly grasp one of the most important fundamental aspects of life itself, the transfer of information from one to another, individuals or groups, without language nothing can be understood.

Psient also looks at Earth, nature and the environment, this section also covers pollution, its important to see how the Psage must remain responsible for nature and the environment. See how this relates to science in biology and ONA, we are what we breathe and if our environment is polluted our RNA is certainly aware of that.

Psient includes Socilitarian and Cultural aspects of life and discuss’s with variety including politics professional activities as well as cultural one such as the arts and music. Psient discuss’s the relation of sexuality; Psient also discuss’s the act of sex in detail.

Psient has a wide grasp of subjects, theories and hypotheses, hopefully enough to spend the rest of your life reading and explaining defnitions of existence and understanding; Psient was sourced from the Wikipedia, hence the density and diversity of each topic throughout the book.

Psient believe’s that the only true piece of land they own is the piece directly beneath they’re feet as they move this thus changes, yet really God owns the land. Bless the son, the father and the holy Ghost -

5 Day and Night - God suggests you experience a full day as an adult, this mean staying awake for around 20 hours and having only 4 hours sleep between the hours of 2am and 6am.

Hygiene: Hygiene is a set of practices performed to preserve health. Use our water to clean yourself of anything with prayer - use an inducement shower to start - tell the body to absorb the water as you take a shower you will see your inside body turn light blue. Tere are 2107 inducement points for water- especially good are the ears - you will hear the skull fll, it is good to use countdowns in accordance with the lord’s advice to fll the body as you may food the body if you induce water for too long, be careful, the top of the head is for the skeleton and for best result turn on the shower from cold and start from the cranial this improves the optics. Prayer - Tank the water for the blessing - Amen’ too the water sources! Be clean for the lord, thanks be too God.

Prayer has timing rhythm and composure, discipline and focus in accordance with God and his guidance (recite Amen on 0th of counting precise, otherwise aim to go over not under but be exact too 0.000+th and the lord will thank you. Make sure you pray for a godly purpose, God will guide you. Prayers are usually for healing!

Praying and hygiene is atmospheric engineering of the body at the divine high level. If it really is too much for you you may ask a member of the clergy.

6 2) Laws and Justice

Love is the law and the law is love, God is Love and god is the Law. - Above the Law.

Te only way too break the law is too harm someone or something. - Fundamental Law

Laws apply Tought, Word Deed. Inside the body and out.

If you break the law you may be punished until you pray away your sins , change your ways and seek redemption, remorse may help during this period.. Te may mean a prison sentence - spend it praying to heal the damage you cause - prayer can heal physiology and heal the body - this implies forgiveness, God will tell you when you have healed some one and become forgiven.

If you keep all of these laws you will live in complete freedom on earth and forever after; you will rise into heaven at peace.

Respect Nature and God Bless.

Law One - Do Not Harm anything.

Laws to thought, word and deed. Tis includes affecting conscious free will in others, unless you are adding love and lordship; godly experience If 0 was not thinking and 1 was thinking; then 2 would be forcing someone to think something. For example dangerous uses of wiccan are the the worst for this as spells contain potent physics that affect/effect autonomy or emotion - avoid vexatious people like this for they are dangerous and uncaring in psychological terms they cause a mental psychosis that can override an individual’s awareness and give then mental disabilities. If some attacks you on the inside; this is illegal report it too the police. God’s will is greater than any other, that depends on constant discussion with God.

Stealing is seen to hurt and cause emotional strain on others, thus so is illegal , and thus is included in this foremost law. Obviously violence, rape and murder are the most illegal examples of breaking this law. Ten war mongery and terrorism, espionage and sabotage all relate to this law, destroying somthing, can harm someone, in stealing, the owner of the object. Harm is a moral, ethical and legal concept.

Bernard Gert construes harms as any of the following: Pain, Murder, disability, loss of ability or freedom, loss of pleasure. Joel Feinberg gives an account of harms as setbacks to interests. He distinguishes welfare interests from ulterior interests. Hence on his view there are two kinds of harms.

Pain is a distressing feeling often caused by intense or damaging stimuli. Te International Association for the Study of Pain's widely used defnition defnes pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage, however, due to it being a complex, subjective phenomenon, defning pain has been a challenge. In medical diagnosis, pain is regarded as a symptom of an underlying condition.

7 Pain motivates the individual to withdraw from damaging situations, to protect a damaged body part while it heals, and to avoid similar experiences in the future. Most pain resolves once the noxious stimulus is removed and the body has healed, but it may persist despite removal of the stimulus and apparent healing of the body. Sometimes pain arises in the absence of any detectable stimulus, damage or disease. Prayer can heal pain.

Pain is the most common reason for physician consultation in most developed countries. It is a major symptom in many medical conditions, and can interfere with a person's quality of life and general functioning. Psychological factors such as social support, hypnotic suggestion, excitement, or distraction can signifcantly aﬀect pain's intensity or unpleasantness. In some arguments put forth in physician-assisted suicide or euthanasia debates, pain has been used as an argument to permit people who are terminally ill to end their lives. Tuning prayer’s to God can heal anything.

Welfare interests are interests in the continuance for a foreseeable interval of one's life, and the interests in one's own physical health and vigor, the integrity and normal functioning of one's body, the absence of absorbing pain and suﬀering or grotesque disfgurement, minimal intellectual acuity, emotional stability, the absence of groundless anxieties and resentments, the capacity to engage normally in social intercourse and to enjoy and maintain friendships, at least minimal income and fnancial security, a tolerable social and physical environment, and a certain amount of freedom from interference and coercion. It is mental health law that if someone is declared mad, they have been committed too judgement of another kind, society handles this with it structure; there are grades of mental illness - like fault lines that judge whom is mad or who derated madness in another- have patience with these people; they need help.

Ulterior interests are "a person's more ultimate goals and aspirations," such as "producing good novels or works of art, solving a crucial scientifc problem, achieving high political oﬃce, successfully raising a family . . .".

Te laws - Tell the truth as it forms reality

Truth is most often used to mean being in accord with fact or reality, or fdelity to an original or standard. Truth may also often be used in modern contexts to refer to an idea of "truth to self," or authenticity. If you lie you must tell the truth within 3 seconds or God will punish you.

Truth is usually held to be opposite too falsehood, which, correspondingly, can also take on a logical, factual, or ethical meaning. Te concept of truth is discussed and debated in several contexts, including philosophy, art, and religion. Many human activities depend upon the concept, where it’s nature as a concept is assumed rather than being a subject of discussion; these include most of the sciences, law, journalism, and everyday life. Some philosophers view the concept of truth as basic, and unable to be explained in any terms that are more easily understood than the concept of truth itself. Commonly, truth is viewed as the correspondence of language or thought to an independent reality, in what is sometimes called the correspondence theory of truth.

Other philosophers take this common meaning to be secondary and derivative. According to Martin Heidegger, the original meaning and essence of truth in Ancient Greece was unconcealment, or the revealing or bringing of what was previously hidden into the open, as indicated by the original Greek term for truth, aletheia. On this view, the conception of truth as correctness is a later derivation from the concept's original essence, a development Heidegger traces to the Latin term veritas.

Various theories and views of truth continue to be debated among scholars, philosophers, and theologians. Language and words are a means by which humans convey information to one another and the method used to determine what is a "truth" is termed a criterion of truth. Tere are diﬀering claims on such questions as what constitutes truth: what things are truthbearers capable of being true or false; how to defne, identify, and distinguish truth; the roles that faith-based and empirically based knowledge play; and whether truth is subjective or objective, relative or absolute.

From ancient, metaphysical belief in the divinity of Truth lies at the heart of belief and has served as the foundation for the entire subsequent faith in belief rests —that God is Truth; that Truth is ‘Divine'..."

In mathematics, existence is asserted by a quantifer, the existential quantifer, one of two quantifers (the other being the universal quantifer). Te properties of the existential quantifer are established by axioms.

An axiom or postulate is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments. Te word comes from the Greek axíōma (ἀξίωμα) 'that which is thought worthy or ft' or 'that which commends itself as evident.'

8 Te term has subtle diﬀerences in defnition when used in the context of diﬀerent felds of study. As defned in classic philosophy, an axiom is a statement that is so evident or well-established, that it is accepted without controversy or question. [3] As used in modern logic, an axiom is a premise or starting point for reasoning.

As used in mathematics, the term axiom is used in two related but distinguishable senses: "logical axioms" and "non-logical axioms". Logical axioms are usually statements that are taken to be true within the system of logic they defne (e.g., (A and B) implies A), often shown in symbolic form, while non-logical axioms (e.g., a + b = b + a) are actually substantive assertions about the elements of the domain of a specifc mathematical theory (such as arithmetic). When used in the latter sense, "axiom", "postulate", and "assumption" may be used interchangeably. In general, a non-logical axiom is not a self-evident truth, but rather a formal logical expression used in deduction to build a mathematical theory. To axiomatize a system of knowledge is to show that its claims can be derived from a small, well-understood set of sentences (the axioms). Tere are typically multiple ways to axiomatize a given mathematical domain.

Any axiom is a statement that serves as a starting point from which other statements are logically derived. Whether it is meaningful (and, if so, what it means) for an axiom to be "true" is a subject of debate in the philosophy of mathematics.

Te philosopher Michel Foucault wrote that Te Logic of Sense "should be read as the boldest and most insolent of metaphysical treatises - on the simple condition that instead of denouncing metaphysics as the neglect of being, we force it to speak of extrabeing".[2] Te philosopher Christopher Norris believes that, like Diﬀerence and Repetition (1968), Te Logic of Sense comes as near as possible to oﬀering a full-scale programmatic statement of Deleuze's post- philosophical, anti-systematic, ultra-nominalist or resolutely "non-totalizing" mode of thought.

Te physicists Alan Sokal and Jean Bricmont write in Fashionable Nonsense (1997) that Te Logic of Sense prefgures the style of works that Deleuze later wrote in collaboration with Félix Guattari, and that, like them, it contains passages in which Deleuze misuses technical scientifc terms.[4] Josuha Ramey describes Te Logic of Sense as Deleuze's "most sustained ethical refection". Timothy Laurie argues that Deleuze presents "sense" as wrapped up in a problematic, and that a problematic cannot be evaluated according to truth and error, nor is it ever exhausted through one single solution.

A paradox is a statement that, despite apparently valid reasoning from true premises, leads to an apparently-self- contradictory or logically unacceptable conclusion. A paradox involves contradictory-yet-interrelated elements that exist simultaneously and persist over time.

Some logical paradoxes are known to be invalid arguments but are still valuable in promoting critical thinking.[6]

Some paradoxes have revealed errors in defnitions assumed to be rigorous, and have caused axioms of mathematics and logic to be re-examined. One example is Russell's paradox, which questions whether a "list of all lists that do not contain themselves" would include itself, and showed that attempts to found set theory on the identifcation of sets with properties or predicates were fawed. Others, such as Curry's paradox, are not yet resolved.

Examples outside logic include the ship of Teseus from philosophy (questioning whether a ship repaired over time by replacing each and all of its wooden parts, one at a time, would remain the same ship). Paradoxes can also take the form of images or other media. For example, M.C. Escher featured perspective-based paradoxes in many of his drawings, with walls that are regarded as foors from other points of view, and staircases that appear to climb endlessly.

In common usage, the word "paradox" often refers to statements that are ironic or unexpected, such as "the paradox that standing is more tiring than walking”.

Reality is the sum or aggregate of all that is real or existent, as opposed to that which is merely imaginary. Te term is also used to refer to the ontological status of things, indicating their existence. In physical terms, reality is the totality of the universe, known and unknown. Philosophical questions about the nature of reality or existence or being are considered under the rubric of ontology, which is a major branch of metaphysics in the Western philosophical tradition. Ontological questions also feature in diverse branches of philosophy, including the philosophy of science, philosophy of religion, philosophy of mathematics, and philosophical logic. Tese include questions about whether only physical objects are real (i.e., Physicalism), whether reality is fundamentally immaterial (e.g., Idealism), whether hypothetical unobservable entities posited by scientifc theories exist, whether God exists, whether numbers and other abstract objects exist, and that possible worlds exist.

Te Laws - You are responsible for your own actions

9 Each action can be measured by the creed of thought, word and deed - if someone’s pestulant thought corrupts another’s- then that person is responsible for they’re thinking toward the other the law will deal with them, police; also the other is responsible for managing that thought yet can blame the other. Mental health law can interplay- i.e. if someone is forced to think something unrational or dangerous, are they then responsible for they’re actions? Yes, this is still true, yet the is a describable context of rational for the person who the forced ill thought in the frst place, this cannot be ignored as illegal- aﬀecting free/god’s will; here an individuals free will can be determined by any other but then is it free, or godly. Te only way around thinking into another will is too add intelligence or wisdom- if one is more intelligent than another- information shared comprises that knowledge is power and can free will into god’s own thought. Consult God on this.

In philosophy, an action is something which is done by an agent. In common speech, the term action is often used interchangeably with the term behavior. However, in the philosophy of action, the behavioural sciences, and the social sciences, a distinction is made: behavior is defned as automatic and refexive activity, while action is defned as intentional, purposive, conscious and subjectively meaningful activity with objective’s. Tus, throwing a ball is an instance of action; it involves an intention, a goal, and a bodily movement guided by the agent. On the other hand, catching a cold is not considered an action because it is something which happens to a person, not something done by one. As Desmond Tutu suggested sometimes it is inaction of the otherwise ‘responsible’, that can cause the occurrence of a deadly event; if you know better, can you help stop something bad before it happens by intervening God bless’s this action.

In enactivism theory, perception is understood to be sensorimotor in nature. Tat is, we carry out actions as an essential part of perceiving the world. Alva Noë states:

We move our eyes, head and body in taking in what is around us... [we] crane our necks, peer, squint, reach for our glasses or draw near to get a better look...'...'Perception is a mode of activity on the part of the whole animal...It cannot be represented in terms of merely passive, and internal, processes...'

Some would prefer to defne actions as requiring bodily movement (see behaviorism). Te side effects of actions are considered by some to be part of the action; in an example from Anscombe's manuscript Intention, pumping water that is poisoned - without knowing it is so introduces a moral dimension to the discussion (see also Moral agency). If the poisoned water resulted in a death, that death might be considered part of the action of the agent that pumped the water. Whether a side effect is considered part of an action is especially unclear in cases in which the agent isn't aware of the possible side effects.

A primary concern of philosophy of action is to analyze the nature of actions and distinguish them from similar phenomena. Other concerns include individuating actions, explaining the relationship between actions and their eﬀects, explaining how an action is related to the beliefs and desires which cause and/ or justify it (see practical reason), as well as examining the nature of agency. A primary concern is the nature of free will and whether actions are determined by the mental states that precede them (see determinism). Some philosophers (e.g. Donald Davidson) have argued that the mental states the agent invokes as justifying his action are physical states that cause the action. Problems have been raised for this view because the mental states seem to be reduce to mere physical causes. Teir mental properties don't seem to be doing any work. If the reasons an agent cites as justifying his action, however, are not the cause of the action, they must explain the action in some other way or be causally impotent.

In sociology, social action, also known as "Weberian social action", refers to an act which takes into account the actions and reactions of individuals (or 'agents'). According to Max Weber, "an Action is 'social' if the acting individual takes account of the behavior of others and is thereby oriented in its course". Our act in society measures us greatly and refects in everything we do.

Te basic concept was primarily developed in the non-positivist theory of Max Weber to observe how human behaviors relate to cause and eﬀect in the social realm. For Weber, sociology is the study of society and behavior and must therefore look at the heart of interaction. Te theory of social action, more than structural functionalist positions, accepts and assumes that humans vary their actions according to social contexts and how it will aﬀect other people; when a potential reaction is not desirable, the action is modifed accordingly. Action can mean either a basic action (one that has a meaning) or an advanced social action, which not only has a meaning but is directed at other actors and causes action (or, perhaps, inaction).

[Sociology is] ... the science whose object is to interpret the meaning of social action and thereby give a causal explanation of the way in which the action proceeds and the eﬀects which it produces. By 'action' in this defnition is meant the human behavior when and to the extent that the agent or agents see it as subjectively meaningful ... the meaning to which we refer may be either (a) the meaning actually intended either by an individual agent on a particular historical occasion or by a number of agents on an approximate average in a given set of cases, or (b) the meaning attributed to the agent or agents, as types, in a pure type constructed in the abstract. In neither case is the 'meaning' to be thought of as somehow objectively

10 'correct' or 'true' by some metaphysical criterion. Tis is the diﬀerence between the empirical sciences of action, such as sociology and history, and any kind of priori discipline, such as jurisprudence, logic, ethics, or aesthetics whose aim is to extract from their subject-matter 'correct' or 'valid' meaning.

Te term is more practical and encompassing than Florian Znaniecki's "social phenomena", since the individual performing social action is not passive, but rather active and reactive - Bob Marley , Every Little Action has a Reaction. Although Weber himself used the word 'agency', in modern social science this term is often appropriated with a given acceptance of Weberian conceptions of social action, unless a work intends to make the direct allusion. Similarly, 'refexivity' is commonly used as a shorthand to refer to the circular relationship of cause and eﬀect between structure and agency.

Rational actions: actions which are taken because it leads to a valued goal, but with no thought of its consequences and often without consideration of the appropriateness of the means chosen to achieve it ('the end justifes the means'). Value rational or Instrumentally rational social action is divided into two groups: rational consideration and rational orientation. Rational consideration is when secondary results are taken into account rationally. Tis is also considered alternative means when secondary consequences have ended. Determining this mean of action is quite hard and even incompatible. Rational orientation is being able to recognize and understand certain mediums under common conditions. According to Weber, heterogeneous actors and groups that are competing, fnd it hard to settle on a certain medium and understand the common social action; Instrumental action (also known as value relation, goal-instrumental ones, zweckrational): actions which are planned and taken after evaluating the goal in relation to other goals, and after thorough consideration of various means (and consequences) to achieve it. An example would be a high school student preparing for life as a lawyer. Te student knows that in order to get into college, he/she must take the appropriate tests and fll out the proper forms to get into college and then do well in college in order to get into law school and ultimately realize his/her goal of becoming a lawyer. If the student chooses not to do well in college, he/she knows that it will be diﬃcult to get into law school and ultimate. Further if the subjects predetermined them to be professional specifc via God, or are they heard in the wrong direction according God, some one in the wrong position professionally can be a real danger; this often happens en-mass, after a war, the same with partners; it takes Prophets and spiritual discussion to reset things.

Another example would be most economic transactions. Value Relation is divided into the subgroups commands and demands. According to the law, people are given commands and must use the whole system of private laws to break down the central government or domination in the legal rights in which a citizen possess. Demands can be based on justice or human dignity just for morality. Tese demands have posed several problems even legal formalism has been put to the test. Tese demands seem to weigh on the society and at times can make them feel immoral.

Te rational choice approach to religion draws a close analogy between religion and the market economy. Religious frms compete against one another to oﬀer religious products and services to consumers, who choose between the frms. To the extent that there are many religious frms competing against each other, they will tend to specialize and cater to the particular needs of some segments of religious consumers. Tis specialization and catering in turn increase the number of religious consumers actively engaged in the religious economy. Tis proposition has been confrmed in a number of empirical studies.

Affective action (also known as emotional actions): actions which are taken due to 'one's emotions, to express personal feelings. For example; cheering after a victory; crying at a funeral- would be affective actions. Affective is divided into two subgroups: uncontrolled reaction and emotional tension. In uncontrolled reaction there is no restraint and there is lack of discretion. A person with an uncontrolled reaction becomes less inclined to consider other peoples’ feelings as much as their own. Emotional tension comes from a basic belief that a person is unworthy or powerless to obtain his/her deepest aspirations. When aspirations are not fulflled there is internal unrest. It is often difficult to be productive in society because of the unfulflled life. Emotion is often neglected because of concepts at the core of exchange theory. A common example is behavioral and rational choice assumptions. From the behavioral view, emotions are often inseparable from punishments. Emotion: Emotions are one's feelings in response to a certain situation. Tere are six types of emotion: social emotions, counterfactual emotions, emotions generated by what may happen (often manifested as anxiety), emotions generated by joy and grief (examples found in responses typically seen when a student gets a good grade, and when a person is at a funeral, respectively), thought-triggered emotions (sometimes manifested as fashbacks), and fnally emotions of love and disgust. All of these emotions are considered to be unresolved. Tere are six features that are used to defne emotions: intentional objects, valence, cognitive antecedents, physiological arousal, action tendencies, and lastly physiological expressions. Tese six concepts were identifed by Aristotle and are still the topic of several talks.

11 Justice and Criminology

Justice is the legal or philosophical theory by which fairness is administered. Te concept of justice diﬀers in every culture. An early theory of justice was set out by the Ancient Greek philosopher Plato in his work Te Republic. Advocates of divine command theory argue that justice issues from God. In the 17th century, theorists like John Locke argued for the theory of natural law. Tinkers in the social contract tradition argued that justice is derived from the mutual agreement of everyone concerned. In the 19th century, utilitarian thinkers including John Stuart Mill argued that justice is what has the best consequences. Teories of distributive justice concern what is distributed, between whom they are to be distributed, and what is the proper distribution. Egalitarians argued that justice can only exist within the coordinates of equality. John Rawls used a social contract argument to show that justice, and especially distributive justice, is a form of fairness. Property rights theorists (like Robert Nozick) take a deontological view of distributive justice and argue that property rights-based justice maximizes the overall wealth of an economic system. Teories of retributive justice are concerned with punishment for wrongdoing. Restorative justice (also sometimes called "reparative justice") is an approach to justice that focuses on restoring what is good, and necessarily focuses on the needs of victims and oﬀenders.

In his dialogue Republic, Plato uses Socrates to argue for justice that covers both the just person and the just City State. Justice is a proper, harmonious relationship between the warring parts of the person or city. Hence, Plato's defnition of justice is that justice is the having and doing of what is one's own. A just man is a man in just the right place, doing his best and giving the precise equivalent of what he has received. Tis applies both at the individual level and at the universal level. A person's soul has three parts – reason, spirit and desire. Similarly, a city has three parts – Socrates uses the parable of the chariot to illustrate his point: a chariot works as a whole because the two horses' power is directed by the charioteer. Lovers of wisdom – philosophers, in one sense of the term – should rule because only they understand what is good. If one is ill, one goes to a medic rather than a farmer, because the medic is expert in the subject of health. Similarly, one should trust one's city to an expert in the subject of the good, not to a mere politician who tries to gain power by giving people what they want, rather than what's good for them. Socrates uses the parable of the ship to illustrate this point: the unjust city is like a ship in open ocean, crewed by a powerful but drunken captain (the common people), a group of untrustworthy advisors who try to manipulate the captain into giving them power over the ship's course (the politicians), and a navigator (the philosopher) who is the only one who knows how to get the ship to port. For Socrates, the only way the ship will reach its destination – the good – is if the navigator takes charge.

Advocates of divine command theory argue that justice, and indeed the whole of morality, is the authoritative command of God. Murder is wrong and must be punished, for instance, because, and only because, God commands that it be so.

Divine command theory was famously questioned by Plato in his dialogue, Euthyphro. Called the Euthyphro dilemma, it goes as follows: "Is what is morally good commanded by God because it is morally good, or is it morally good because it is commanded by God?" Te implication is that if the latter is true, then justice is arbitrary; if the former is true, then god existance is similar to that of morality, he who becomes little more than a passer-on of moral knowledge is Psient.

Many apologists have addressed the issue, typically by arguing that is it a false dilemma. For example, some apologists argue that goodness is the very nature of God, and there is necessarily refected in His commands. Discussion is preferred yet argument often unaviodable too prove a point; if one knows better. However, this merely pushes the problem back further, as to where God's nature comes from. If from himself, then it is still arbitrary, if from something else, then it is something higher than God. (Attempts to answer this typically argues that goodness is necessarily tied with God's character.) Another response, popularized in two contexts by Immanuel Kant and C. S. Lewis, is that it is deductively valid to argue that the existence of an objective morality implies the existence of God and vice versa. But some critics argue that the existence of objective morality has nothing to do with the existence of God.

For advocates of the theory that justice is part of natural law (e.g., John Locke), it involves the system of consequences that naturally derives from any action or choice. In this, it is similar to the laws of physics: in the same way as the Tird of Newton's laws of Motion requires that for every action there must be an equal and opposite reaction, justice requires according individuals or groups what they actually deserve, merit, or are entitled to. Justice, on this account, is a universal and absolute concept: laws, principles, religions, etc., are merely attempts to codify that concept, sometimes with results that entirely contradict the true nature of justice.

In contrast to the understandings canvassed so far, justice may be understood as a human creation, rather than a discovery of harmony, divine command, or natural law. Tis claim can be understood in a number of ways, with the fundamental division being between those who argue that justice is the creation of some humans, and those who argue that it is the creation of all humans.

12 Despotism and skepticism In Republic by Plato, the character Trasymachus argues that justice is the interest of the strong – merely a name for what the powerful or cunning ruler has imposed on the people.

According to thinkers in the social contract tradition, justice is derived from the mutual agreement of everyone concerned; or, in many versions, from what they would agree to under hypothetical conditions including equality and absence of bias. Tis account is considered, under 'Justice as fairness'. Te absence of bias refers to an equal ground for all people concerned in a disagreement (or trial in some cases).

Criminology (from Latin crīmen, "accusation" originally derived from the Ancient Greek verb "krino" "κρίνω", and Ancient Greek -λογία, -logy|-logia, from "logos" meaning: “word,” “reason,” or “plan”) is the scientifc study of the nature, extent, management, causes, control, consequences, and prevention of criminal behavior, both on the individual and social levels. Criminology is an interdisciplinary feld in both the behavioral and social sciences, drawing especially upon the research of sociologists, psychologists, philosophers, psychiatrists, social anthropologists, as well as scholars of law.

Te term criminology was coined in 1885 by Italian law professor Raﬀaele Garofalo as criminologia. Later, French anthropologist Paul Topinard used the analogous French term criminologie.

Teonomy states that all these laws apply too you - God and justice, especially for health reason’s, Mind Body and Soul and your relation with God - is someone aﬀecting your relation with God? Always ask more question and seek more answers. Form comprehension and debate. Word be too god, thought and word we celebrate the word of God.

Nomos or Nome may refer to: from the Greek term for "law" (νόμος, nómos; pl. νόμοι, nómoi). It is the origin of the suﬃx -onomy, as in astronomy, economy, or taxonomy. custom, traditional social norm, the equivalent of Latin Mores. Tere are laws too everything.

Dramatis Personi - Glamangi Latin for i’m was merely acting; intending no harm. If someone fools with you maybe you can fool them back.

13 3) Miracles

First the miracle of healing for God’s healing to work try this, frst you must be connected to God so if you haven’t said it say ‘I believe in you God’ through inner voice, God will appear and say thankyou. Next say to God, ‘will you God the only one that can heal me on the inside’ he will heal you. You can also do with for the epidermis, just ask politely., Psient recommends checking every month for this God can heal cancer and anything inside the body but only if you ask. He will do it time and time again. Just say thankyou.

Te Miracles - 1st that we exist.

Existence, in its most generic terms, comprises the state of being real and the ability to physically interact with the universe or multiverse, with belief Heaven, without Hell or Neverland with judgement from the devil and to live with god. What existence is exactly is up for interpretation; and, is one of the most important and fundamental topics of ontology, the philosophical study of the nature of being, existence, or reality in general, as well as of the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology deals with questions concerning what entities exist or can be said to exist, and how such entities can be grouped, related within a hierarchy, and subdivided according to similarities and diﬀerences. Te celestial cosmology and the heavenly heterarchy. Tis reality can be perceived through the senses.

A sense is a physiological capacity of organisms that provides data for perception. Te senses and their operation, classifcation, and theory are overlapping topics studied by a variety of felds, most notably neuroscience, cognitive psychology (or cognitive science), and philosophy of perception. Te nervous system has a specifc sensory nervous system, and a sense organ, or sensor, dedicated to each sense.

Humans have a multitude of sensors. Sight (vision), hearing (audition), taste (gustation), smell (olfaction), and touch (somatosensation) are the fve traditionally recognized senses. Te ability to detect other stimuli beyond those governed by these most broadly recognized senses also exists, and these sensory modalities include temperature (thermoception), kinesthetic sense (proprioception), pain (nociception), balance (equilibrioception), vibration (mechanoreception), and various internal stimuli (e.g. the diﬀerent chemoreceptors for detecting salt and carbon dioxide concentrations in the blood, or sense of hunger and sense of thirst). However, what constitutes a sense is a matter of some debate, leading to diﬃculties in defning what exactly a distinct sense is, and where the borders lie between responses to related stimuli also there are sensors for time.

Other animals also have receptors to sense the world around them, with degrees of capability varying greatly between species. Humans have a comparatively weak sense of smell and a stronger sense of sight relative to many other mammals while some animals may lack one or more of the traditional fve senses. Some animals may also intake and interpret sensory stimuli in very diﬀerent ways. Some species of animals are able to sense the world in a way that humans cannot, with some species able to sense electrical and magnetic felds, and detect water pressure and currents.

Te currents and vibrations relate between the conscious and cosmos. In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, which may be centered on Earth or the observer. If centered on the observer, half of the sphere would resemble a hemispherical screen over the observing location. Astral travel can allow you too adventure this medium through perception.

Te celestial sphere is a practical tool for spherical astronomy, allowing astronomers to specify the apparent positions of objects in the sky if their distances are unknown or irrelevant. In the equatorial coordinate system, the celestial equator divides the celestial sphere into two halves: the northern and southern celestial hemispheres.

Any plane that includes the center of a sphere divides it into two equal hemispheres. Any two intersecting planes that include the center of a sphere subdivide the sphere into four lunes or biangles, the vertices of which all coincide with the antipodal points lying on the line of intersection of the planes.

Te antipodal quotient of the sphere is the surface called the real projective plane, which can also be thought of as the northern hemisphere with antipodal points of the equator identifed.

Te hemisphere is conjured to be the optimal perception of the horizon..

14 Visual perception is the ability to interpret the surrounding environment using light in the visible spectrum refected by the objects in the environment. Tis is diﬀerent from visual acuity, which refers to how clearly a person sees, this is linked too purity and water cleaning hygiene too understand clarity of perception.

Te resulting perception is also known as visual perception, eyesight, sight, or vision (adjectival form: visual, optical, or ocular). Te various physiological components involved in vision are referred to collectively as the visual system, and are the focus of much research in linguistics, psychology, cognitive science, neuroscience, and molecular biology, collectively referred to as vision science. Tis is an external perception.

Mechanosensation is a response mechanism to mechanical stimuli. Te physiological foundation for the senses of touch, hearing and balance, and pain is the conversion of mechanical stimuli into neuronal signals: mechanosensation. Mechanoreceptors of the skin, called cutaneous mechanoreceptors, are responsible for touch. Tiny cells in the inner ear, called hair cells, are responsible for hearing and balance.

Existentialism (/ˌɛɡzɪˈstɛnʃəlɪzəm/[1] or /ˌɛksəˈstɛntʃəˌlɪzəm/[2]) is a tradition of philosophical enquiry which takes as its starting point the experience of the human subject—not merely the thinking subject, but the acting, feeling, living human individual.[3]:14–15 It is associated mainly with certain 19th- and 20th-century European philosophers who, despite profound doctrinal diﬀerences,[4][3]:18–21[5] shared the belief in that beginning of philosophical thinking. While the predominant value of existentialist thought is commonly acknowledged to be freedom, its primary virtue is authenticity.[6] In the view of the existentialist, the individual's starting point is characterized by what has been called "the existential angst" (or variably, existential attitude, dread, etc.), or a sense of disorientation, confusion, or dread in the face of an apparently meaningless or absurd world.[7] Many existentialists have also regarded traditional systematic or academic philosophies, in both style and content, as too abstract and remote from concrete human experience.[8][9] Søren Kierkegaard is generally considered to have been the frst existentialist philosopher,[4][10][11] though he did not use the term existentialism.[12] He proposed that each individual—not society or religion—is solely responsible for giving meaning to life and living it passionately and sincerely, or "authentically".[13][14] Existentialism became popular in the years following World War II, thanks to Jean-Paul Sartre, who read Martin Heidegger while in a POW camp, and strongly infuenced many disciplines besides philosophy, including theology, drama, art, literature, and psychology.

Materialism holds that the only things that exist are matter and energy, that all things are composed of material, that all actions require energy, and that all phenomena (including consciousness) are the result of interactions between states and they’re fux and entropy.

Life is a characteristic which distinguishes meta-physical objects that have self-sustaining biological processes from those that do not—either because such functions have ceased (death material), or else because they lack such functions and are classifed as “inanimate" only AIM (artifcal intelligence machines) can be the diﬀerence theoretically speaking.

Te smallest living things on Earth, single-celled micro-organisms or microbes lacking a cell nucleus or cell membrane known as prokaryotes. Too earth itself being Gaia, like in OOP(Object-Orientated Programming)- each entity has a bigger or smaller grouping a family and an overlord, a seed(entity) becomes a tree(entity) which has leaves(entitiy(s)), which becomes a forest(entity), a part of a land mass (entity) separated and fed by water (entity) part of an planet(entity) and so with each (enitity) so bigger or smaller— Te Gaia hypothesis (/ˈɡaɪ.ə/, /ˈɡeɪ.ə/, /ˈɡaɪˈʌ/), also known as the Gaia theory or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.

Te hypothesis was formulated by the chemist James Lovelock and co-developed by the microbiologist Lynn Margulis in the 1970s. Lovelock named the idea after Gaia, the primordial goddess who personifed the Earth in Greek mythology. In 2006, the Geological Society of London awarded Lovelock the Wollaston Medal in part for his work on the Gaia hypothesis.

Topics related to the hypothesis include how the biosphere and the evolution of organisms aﬀect the stability of global temperature, salinity of seawater, atmospheric oxygen levels, the maintenance of a hydrosphere of liquid water and other environmental variables that aﬀect the habitability of Earth.

15 ecology. Lovelock also once described the "geophysiology" of the Earth. Even so, the Gaia hypothesis continues to attract criticism, and today some scientists consider it to be only weakly supported by, or at odds with, the available evidence.

Planets are incredibly common amongst stars- every star has planets. On average, each of the stars in existence hosts at least 15 planets. In each galaxy there are around 2,000,000,000 earth like planets, each universe has on average 2,000,000,000,000,000,000 galaxies. Tat is life in abundance.

Te Miracles - 2nd that everything appears still..

Te universe is moving , Te galaxy is moving Te Sun's orbiting around the Galaxy. Te speed of the ground beneath your feet, as a result of the Earth's rotation: 694 mph (at 52 degrees lean) at the equator. and the earth orbits the sun at 4,7913,20mph Te moon rotates at 371mph, and orbits at 3,792mph. Yet as you look out, everything is perfectly still.

Te motion that's left must be the particular motion of our Galaxy through the universe! Te speed turns out to be an astounding 4ish billion miles per hour)! Te universe is moving at about 4 trillion miles an hour.

Te moon orbits the Earth once every 27.322 days. It also takes approximately 17 hours for the moon to rotate once on its axis. As a result, the moon does not seem to be spinning but appears to observers from Earth to be keeping almost perfectly still. Scientists call this synchronous rotation. Every intergalactic body does this in relation to everything else.

Tus so and in all this taken into account Psient suggests that the stillness we perceive is a miracle.

Stillness

Stillness is the most fundamental of Te Great Practices of the New Message from God. Te still mind can see, hear and discern. Relationship and truth can be known in stillness.

Knowledge, and on rare occasions the Unseen Ones, can be heard in a mind that has cultivated stillness. Space has been made, to hear beyond the fear, desire and assumptions of the personal mind.

"Knowledge will not arise in a preoccupied mind under normal circumstances."[1]

"You practice stillness not to get anything, but to learn to be still. You learn to be still so that you can feel and listen."[2]

Knowing in stillness

"In stillness and quiet, everything becomes apparent." [3]

"Be careful. Become present. If you are still and observant, you will be able to see what others miss." [4]

"Silence is the experience of profound relationship, and stillness is the acceptance of profound love. [5]

"Stillness is a wonderful, glorious experience in and of itself. It is being at peace. It is being quiet. Tere are no problems to solve, no answers to acquire, no situations to work out, no future to plan for, no past to fret over. Here you are, right here, right now, an incomparable experience—so vast, so pervasive, so reassuring. Only experience can show you that this is true." [6]

Growing in Stillness

"Life gives to you as you are still." [7]

"When your mind is still, you will know. When the mind is still, you will be able to respond. When the mind is still, you will be able to take the next step." [6] 16 "Stillness of mind allows a Greater Mind to emerge and to reveal its Wisdom. Tose who cultivate stillness with a desire for Knowledge will be preparing themselves for greater revelation and true insight to emerge." [8]

"Here stillness enables the mind to become a more powerful instrument, more penetrating in its insight, deeper in its contemplation, more focused in its problem solving and more present as a vehicle for communication." [6]

"Stillness cultivates the mind to receive. In stillness you fnd that things are known already that you have neglected thus far. From these practice periods your mind will become more refned and have greater depth, greater concentration and a greater focus in all aspects of your life." [9]

"Let Knowledge be your guide and let the world tell you where it is going and what is emerging on the horizon. Be watchful. Still your mind. Set aside your desires and your constant fear by taking the Steps to Knowledge. Receive the Revelation, the New Message for humanity. You are blessed to even know of this." [10]

Stillness Practice

"In learning how to still the mind, you must have a focus, you must be in a quiet place, you must be sitting comfortably, and you must have a passive attitude. Four things are required here. Your passive attitude means you are not aggressively trying to make something happen, or to solve problems or to engage in other kinds of mental activities. You are just there in a relaxed manner. So to sit in meditation and experience nothing but agitation or frustration, clearly means you are not meeting the requirements of the situation. You have to be relaxed; you cannot be aggressive. You breathe deeply. Let your breath take you deeper. You have to have a focus for the mind: an image, a thought, an incantation, something that does not stimulate a lot of intellectual activity, something that the mind can anchor itself upon so you can slip beneath its surface into a well of silence. Within this well of silence, deep within it, is the power and the presence of Knowledge. Here you learn how to slip beneath the mind. " [11]

"Some people need an image; some people need a sound; some people need a repeated breathing; some people just need to relax, but stay focused."

"At the beginning, when people say, 'I cannot do this. I cannot be still. I cannot be quiet. My mind is too restless,' we say, 'Practice. Concentrate.' You may repeat the word Rahn if it helps you. You may count your breaths if that helps you."

"So the question is not whether you will practice or not practice. Te question is what you will practice. You practice stilling the mind—that is a practice. You practice letting the mind run rampant—that is a practice. You avoid all spiritual practices —that is a practice." [6]

"When your mind is very noisy, you practice counting or breathing or listening to your pulse. If your mind is a little unsettled and there is a possibility you may settle down, then we practice with sound. If your mind is settled down, well, you are practicing already.Ten we guide your mind to the presence of the Teachers directly. Te Teachers are like a refection from Heaven. Tey fll your mind full of light. You cannot enter Heaven and still be in the world, but you can experience yourself as an intermediary. Overall, that is the fnal goal.When Heaven, your Home, has been partially established here, then you will be able to serve in a higher capacity. Tat does not mean the world looks any better. It simply means that you are carrying your Home within you." [12]

"Allow your mind to be quiet, for in this you are free."[13] [13]

"In the training in Steps to Knowledge, one of the main things you will learn and will have to reinforce over time is the ability to be still. Tis ability represents a fundamental skill in life. It involves becoming observant, receptive, sensitive, insightful. Here you use your mind rather than be used by it. Here you employ your mind to scan the horizon of your mental and physical environment." [4]

Practices

17 "Stop for a moment. Allow your mind to settle down. Breathe deeply. Go to a quiet place. Set aside your thoughts and your plans, goals and problems long enough, you do this frequently enough and you begin to experience the Presence. After awhile, it just emerges, in small glimpses at frst and then, as you proceed, you will have larger experiences of it, enough to show you what you need to see and know about yourself and about your circumstances. Tis is the process of Revelation." [14]

"Practice in stillness, and do not be discouraged if it is diﬃcult at frst. Simply practice and you will proceed." [15]

"During your time of practice, fnd a comfortable place to sit. Uncross your arms and your legs. Give this practice your total attention, not letting your mind wander to other things." [16]

Preoccupation and Distraction

"As you perform your stillness practice, bring yourself completely to your exercise. It is a form of personal dedication. In most cases, you will dispel anything that distracts you with this sense of dedication. In those situations where you cannot overcome the preoccupations of the mind, become a detached witness to them." [17]

"People ask, 'Well, I want to know the answer to my great question.' I say, 'Practice.' Tey say, 'Well, I am looking for the realizations that will help me.' I say, 'Practice.' Tey say, 'Well, I have done practices before.' I say, 'No. Practice. Give yourself.' Tey ask, 'How long will it take?' I say, 'It takes a year to get started. It takes three to fve years to become basically competent, if you practice well.' Tey say, 'I don’t have that kind of time. I cannot make that kind of investment.' Ten I say, 'You are not then serious in your pursuit. You will spend the next fve years wasting your time, looking for answers, looking for things to believe in, looking for better beliefs, trying to manipulate the personal mind so it can provide you what you want, what you need. But the personal mind cannot do it. It can only be a vehicle for a greater mind within you, and here it fulflls its purpose.'" [6]

“People are so frightened and so driven and so compulsive, they cannot be still for fve seconds. Tey close their eyes to begin meditation, and their mind is like a wild animal—going everywhere, like all the channels of your television running at once, going from here and there and everywhere.” [18]

Meditations by Timothy Mulchin and Emily Arunarena

Te Miracles 3rd that we evolve / that we can learn

In a sense evolution is growing and learning adapting and changing, living and loving life.

Learning is the process of acquiring new understanding, knowledge, behaviors, skills, values, and preferences.[1] Te ability to learn is possessed by humans, animals, and some machines; there is also evidence for some kind of learning in certain plants.[2] Some learning is immediate, induced by a single event (e.g. being burned by a hot stove), but much skill and knowledge accumulates from repeated experiences. Te changes induced by learning often last a lifetime, and it is hard to distinguish learned material that seems to be "lost" from that which cannot be retrieved.[3] Human learning starts at birth (it might even start before[4]) and continues until death as a consequence of ongoing interactions between people and their environment. Te nature and processes involved in learning are studied in many felds, including educational psychology, neuropsychology, experimental psychology, and pedagogy. Research in such felds has led to the identifcation of various sorts of learning. For example, learning may occur as a result of habituation, or classical conditioning, operant conditioning or as a result of more complex activities such as play, seen only in relatively intelligent animals.[5][6] Learning may occur consciously or without conscious awareness. Learning that an aversive event can't be avoided nor escaped may result in a condition called learned helplessness.[7] Tere is evidence for human behavioral learning prenatally, in which habituation has been observed as early as 32 weeks into gestation, indicating that the central nervous system is sufficiently developed and primed for learning and memory to occur very early on in development.[8] 18 Play has been approached by several theorists as the frst form of learning.[citation needed] Children experiment with the world, learn the rules, and learn to interact through play. Lev Vygotsky agrees that play is pivotal for children's development, since they make meaning of their environment through playing educational games. For Vygotsky, however, play is the frst form of learning language and communication and the stage where a child begins to understand rules and symbols.[9 Non-associative learning refers to "a relatively permanent change in the strength of response to a single stimulus due to repeated exposure to that stimulus."[10] Tis defnition exempt the changes caused by sensory adaptation, fatigue, or injury. Non-associative learning can be divided into habituation and sensitization. Habituation is an example of non-associative learning in which one or more components of an innate response (e.g., response probability, response duration) to a stimulus diminishes when the stimulus is repeated. Tus, habituation must be distinguished from extinction, which is an associative process. In operant extinction, for example, a response declines because it is no longer followed by a reward. An example of habituation can be seen in small song birds—if a stuffed owl (or similar predator) is put into the cage, the birds initially react to it as though it were a real predator. Soon the birds react less, showing habituation. If another stuffed owl is introduced (or the same one removed and re-introduced), the birds react to it again as though it were a predator, demonstrating that it is only a very specifc stimulus that is habituated to (namely, one particular unmoving owl in one place). Te habituation process is faster for stimuli that occur at a high rather than for stimuli that occur at a low rate as well as for the weak and strong stimuli, respectively.[12] Habituation has been shown in essentially every species of animal, as well as the sensitive plant Mimosa pudica[13] and the large protozoan Stentor coeruleus. [14] Tis concept acts in direct opposition to sensitization.[12] Sensitization is an example of non-associative learning in which the progressive amplifcation of a response follows repeated administrations of a stimulus (Bell et al., 1995).[citation needed] Tis is based on the notion that a defensive refex to a stimulus such as withdrawal or escape becomes stronger after the exposure to a different harmful or threatening stimulus.[15] An everyday example of this mechanism is the repeated tonic stimulation of peripheral nerves that occurs if a person rubs their arm continuously. After a while, this stimulation creates a warm sensation that eventually turns painful. Te pain results from the progressively amplifed synaptic response of the peripheral nerves warning that the stimulation is harmful.[clarifcation needed] Sensitisation is thought to underlie both adaptive as well as maladaptive learning processes in the organism.[citation needed] Active learning occurs when a person takes control of his/her learning experience. Since understanding information is the key aspect of learning, it is important for learners to recognize what they understand and what they do not. By doing so, they can monitor their own mastery of subjects. Active learning encourages learners to have an internal dialogue in which they verbalize understandings. Tis and other meta-cognitive strategies can be taught to a child over time. Studies within metacognition have proven the value in active learning, claiming that the learning is usually at a stronger level as a result.[17] In addition, learners have more incentive to learn when they have control over not only how they learn but also what they learn.[18] Active learning is a key characteristic of student-centered learning. Conversely, passive learning and direct instruction are characteristics of teacher-centered learning (or traditional education). Associative learning is the process by which a person or animal learns an association between two stimuli or events.[19] In classical conditioning a previously neutral stimulus is repeatedly paired with a refex eliciting stimulus until eventually the neutral stimulus elicits a response on its own. In operant conditioning, a behavior that is reinforced or punished in the presence of a stimulus becomes more or less likely to occur in the presence of that stimulus. In operant conditioning, a reinforcement (by reward) or instead a punishment given after a given behavior, change the frequency and/or form of that behavior. Stimulus present when the behavior/consequence occurs come to control these behavior modifcations. Te typical paradigm for classical conditioning involves repeatedly pairing an unconditioned stimulus (which unfailingly evokes a refexive response) with another previously neutral stimulus (which does not normally evoke the response). Following conditioning, the response occurs both to the unconditioned stimulus and to the other, unrelated stimulus (now referred to as the "conditioned stimulus"). Te response to the conditioned stimulus is termed a conditioned response. Te classic example is Ivan Pavlov and his dogs.[15] Pavlov fed his dogs meat powder, which naturally made the dogs salivate— salivating is a refexive response to the meat powder. Meat powder is the unconditioned stimulus (US) and the salivation is the unconditioned response (UR). Pavlov rang a bell before presenting the meat powder. Te frst time Pavlov rang the bell, the neutral stimulus, the dogs did not salivate, but once he put the meat powder in their mouths they began to salivate. After numerous pairings of bell and food, the dogs learned that the bell signaled that food was about to come, and began to salivate when they heard the bell. Once this occurred, the bell became the conditioned stimulus (CS) and the salivation to the bell became the conditioned response (CR). Classical conditioning has been demonstrated in many species. For example, it is seen in honeybees, in the proboscis extension refex paradigm.[20] It was recently also demonstrated in garden pea plants. [21] Another infuential person in the world of classical conditioning is John B. Watson. Watson's work was very infuential and paved the way for B.F. Skinner's radical behaviorism. Watson's behaviorism (and philosophy of science) stood in direct contrast to Freud and other accounts based largely on introspection. Watson's view was that the introspective method was 19 too subjective, and that we should limit the study of human development to directly observable behaviors. In 1913, Watson published the article "Psychology as the Behaviorist Views," in which he argued that laboratory studies should serve psychology best as a science. Watson's most famous, and controversial, experiment, "Little Albert", where he demonstrated how psychologists can account for the learning of emotion through classical conditioning principles. Observational learning is learning that occurs through observing the behavior of others. It is a form of social learning which takes various forms, based on various processes. In humans, this form of learning seems to not need reinforcement to occur, but instead, requires a social model such as a parent, sibling, friend, or teacher with surroundings. Imprinting is a kind of learning occurring at a particular life stage that is rapid and apparently independent of the consequences of behavior. In flial imprinting, young animals, particularly birds, form an association with another individual or in some cases, an object, that they respond to as they would to a parent. In 1935, the Austrian Zoologist Konrad Lorenz discovered that certain birds follow and form a bond if the object makes sounds. Play generally describes behavior with no particular end in itself, but that improves performance in similar future situations. Tis is seen in a wide variety of vertebrates besides humans, but is mostly limited to mammals and birds. Cats are known to play with a ball of string when young, which gives them experience with catching prey. Besides inanimate objects, animals may play with other members of their own species or other animals, such as orcas playing with seals they have caught. Play involves a signifcant cost to animals, such as increased vulnerability to predators and the risk of injury and possibly infection. It also consumes energy, so there must be signifcant benefts associated with play for it to have evolved. Play is generally seen in younger animals, suggesting a link with learning. However, it may also have other benefts not associated directly with learning, for example improving physical ftness. Play, as it pertains to humans as a form of learning is central to a child's learning and development. Trough play, children learn social skills such as sharing and collaboration. Children develop emotional skills such as learning to deal with the emotion of anger, through play activities. As a form of learning, play also facilitates the development of thinking and language skills in children.[22] Tere are fve types of play: sensorimotor play aka functional play, characterized by repetition of activity, role play occurs starting at the age of 3, rule-based play where authoritative prescribed codes of conduct are primary, construction play involves experimentation and building, movement play aka physical play[22] Tese fve types of play are often intersecting. All types of play generate thinking and problem-solving skills in children. Children learn to think creatively when they learn through play.[23] Specifc activities involved in each type of play change over time as humans progress through the lifespan. Play as a form of learning, can occur solitarily, or involve interacting with others. Enculturation is the process by which people learn values and behaviors that are appropriate or necessary in their surrounding culture.[24] Parents, other adults, and peers shape the individual's understanding of these values.[24] If successful, enculturation results in competence in the language, values and rituals of the culture.[24] Tis is different from acculturation, where a person adopts the values and societal rules of a culture different from their native one. Multiple examples of enculturation can be found cross-culturally. Collaborative practices in the Mazahua people have shown that participation in everyday interaction and later learning activities contributed to enculturation rooted in nonverbal social experience.[25] As the children participated in everyday activities, they learned the cultural signifcance of these interactions. Te collaborative and helpful behaviors exhibited by Mexican and Mexican-heritage children is a cultural practice known as being "acomedido".[26] Chillihuani girls in Peru described themselves as weaving constantly, following behavior shown by the other adults.[27] Episodic learning is a change in behavior that occurs as a result of an event.[28] For example, a fear of dogs that follows being bitten by a dog is episodic learning. Episodic learning is so named because events are recorded into episodic memory, which is one of the three forms of explicit learning and retrieval, along with perceptual memory and semantic memory.[29] Episodic memory remembers events and history that are embedded in experience and this is distinguished from semantic memory, which attempts to extract facts out of their experiential context[30] or – as some describe – a timeless organization of knowledge.[31] For instance, if a person remembers the Grand Canyon from a recent visit, it is an episodic memory. He would use semantic memory to answer someone who would ask him information such as where the Grand Canyon is. A study revealed that humans are very accurate in the recognition of episodic memory even without deliberate intention to memorize it.[32] Tis is said to indicate a very large storage capacity of the brain for things that people pay attention to.[32] Multimedia learning is where a person uses both auditory and visual stimuli to learn information (Mayer 2001). Tis type of learning relies on dual-coding theory (Paivio 1971) Electronic learning or e-learning is computer-enhanced learning. A specifc and always more diffused e-learning is mobile learning (m-learning), which uses different mobile telecommunication equipment, such as cellular phones.

20 When a learner interacts with the e-learning environment, it's called augmented learning. By adapting to the needs of individuals, the context-driven instruction can be dynamically tailored to the learner's natural environment. Augmented digital content may include text, images, video, audio (music and voice). By personalizing instruction, augmented learning has been shown to improve learning performance for a lifetime.[33] See also minimally invasive education. Moore (1989)[34] purported that three core types of interaction are necessary for quality, eﬀective online learning: learner– learner (i.e. communication between and among peers with or without the teacher present), learner–instructor (i.e. student teacher communication), and learner–content (i.e. intellectually interacting with content that results in changes in learners' understanding, perceptions, and cognitive structures). In his theory of transactional distance, Moore (1993)[35] contented that structure and interaction or dialogue bridge the gap in understanding and communication that is created by geographical distances (known as transactional distance). Rote learning is memorizing information so that it can be recalled by the learner exactly the way it was read or heard. Te major technique used for rote learning is learning by repetition, based on the idea that a learner can recall the material exactly (but not its meaning) if the information is repeatedly processed. Rote learning is used in diverse areas, from mathematics to music to religion. Although it has been criticized by some educators, rote learning is a necessary precursor to meaningful learning. Meaningful learning is the concept that learned knowledge (e.g., a fact) is fully understood to the extent that it relates to other knowledge. To this end, meaningful learning contrasts with rote learning in which information is acquired without regard to understanding. Meaningful learning, on the other hand, implies there is a comprehensive knowledge of the context of the facts learned.[36] Evidence-based learning is the use of evidence from well designed scientifc studies to accelerate learning. Evidence-based learning methods such as spaced repetition can increase the rate at which a student learns.[37] Formal learning is learning that takes place within a teacher-student relationship, such as in a school system. Te term formal learning has nothing to do with the formality of the learning, but rather the way it is directed and organized. In formal learning, the learning or training departments set out the goals and objectives of the learning.[38] Nonformal learning is organized learning outside the formal learning system. For example, learning by coming together with people with similar interests and exchanging viewpoints, in clubs or in (international) youth organizations, workshops. Informal learning is less structured than "nonformal" one. It may occur through the experience of day-to-day situations (for example, one would learn to look ahead while walking because of the danger inherent in not paying attention to where one is going). It is learning from life, during a meal at table with parents, play, exploring, etc.

Te educational system may use a combination of formal, informal, and nonformal learning methods. Te UN and EU recognize these different forms of learning (cf. links below). In some schools, students can get points that count in the formal-learning systems if they get work done in informal-learning circuits. Tey may be given time to assist international youth workshops and training courses, on the condition they prepare, contribute, share and can prove this offered valuable new insight, helped to acquire new skills, a place to get experience in organizing, teaching, etc. To learn a skill, such as solving a Rubik's Cube quickly, several factors come into play at once: Reading directions helps a player learn the patterns that solve the Rubik's Cube. Practicing the moves repeatedly helps build "muscle memory" and speed. Tinking critically about moves helps fnd shortcuts, which speeds future attempts. Observing the Rubik's Cube's six colors help anchor solutions in the mind. Revisiting the cube occasionally helps retain the skill. Tangential learning is the process by which people self-educate if a topic is exposed to them in a context that they already enjoy. For example, after playing a music-based video game, some people may be motivated to learn how to play a real instrument, or after watching a TV show that references Faust and Lovecraft, some people may be inspired to read the original work.[39] Self-education can be improved with systematization. According to experts in natural learning, self- oriented learning training has proven an effective tool for assisting independent learners with the natural phases of learning. [40] Extra Credits writer and game designer James Portnow was the frst to suggest games as a potential venue for "tangential learning".[41] Mozelius et al.[42] points out that intrinsic integration of learning content seems to be a crucial design factor, and that games that include modules for further self-studies tend to present good results. Te built-in encyclopedias in the Civilization games are presented as an example – by using these modules gamers can dig deeper for knowledge about historical events in the gameplay. Te importance of rules that regulate learning modules and game experience is discussed by Moreno, C.,[43] in a case study about the mobile game Kiwaka. In this game, developed by Landka in collaboration with ESA and ESO, progress is rewarded with educational content, as opposed to traditional education games where learning activities are rewarded with gameplay.[44][45]

21 Dialogic learning is a type of learning based on dialogue. In incidental teaching learning is not planned by the instructor or the student, it occurs as a byproduct of another activity — an experience, observation, self-refection, interaction, unique event, or common routine task. Tis learning happens in addition to or apart from the instructor's plans and the student's expectations. An example of incidental teaching is when the instructor places a train set on top of a cabinet. If the child points or walks towards the cabinet, the instructor prompts the student to say “train.” Once the student says “train,” he gets access to the train set. Here are some steps most commonly used in incidental teaching:[46] An instructor will arrange the learning environment so that necessary materials are within the student's sight, but not within his reach, thus impacting his motivation to seek out those materials. An instructor waits for the student to initiate engagement. An instructor prompts the student to respond if needed. An instructor allows access to an item/activity contingent on a correct response from the student. Te instructor fades out the prompting process over a period of time and subsequent trials. Incidental learning is an occurrence that is not generally accounted for using the traditional methods of instructional objectives and outcomes assessment. Tis type of learning occurs in part as a product of social interaction and active involvement in both online and onsite courses. Research implies that some un-assessed aspects of onsite and online learning challenge the equivalency of education between the two modalities. Both onsite and online learning have distinct advantages with traditional on-campus students experiencing higher degrees of incidental learning in three times as many areas as online students. Additional research is called for to investigate the implications of these fndings both conceptually and pedagogically.[47] Benjamin Bloom has suggested three domains of learning:: Cognitive: To recall, calculate, discuss, analyze, problem solve, etc., Psychomotor: To dance, swim, ski, dive, drive a car, ride a bike, etc., Affective: To like something or someone, love, appreciate, fear, hate, worship, etc. Tese domains are not mutually exclusive. For example, in learning to play chess, the person must learn the rules (cognitive domain)—but must also learn how to set up the chess pieces and how to properly hold and move a chess piece (psychomotor). Furthermore, later in the game the person may even learn to love the game itself, value its applications in life, and appreciate its history (affective domain). Transfer of learning is the application of skill, knowledge or understanding to resolve a novel problem or situation that happens when certain conditions are fulflled. Research indicates that learning transfer is infrequent; most common when "... cued, primed, and guided..."[49] and has sought to clarify what it is, and how it might be promoted through instruction. Over the history of its discourse, various hypotheses and defnitions have been advanced. First, it is speculated that different types of transfer exist, including: near transfer, the application of skill to solve a novel problem in a similar context; and far transfer, the application of skill to solve novel problem presented in a different context.[50] Furthermore, Perkins and Salomon (1992) suggest that positive transfer in cases when learning supports novel problem solving, and negative transfer occurs when prior learning inhibits performance on highly correlated tasks, such as second or third-language learning. [51] Concepts of positive and negative transfer have a long history; researchers in the early 20th century described the possibility that "...habits or mental acts developed by a particular kind of training may inhibit rather than facilitate other mental activities".[52] Finally, Schwarz, Bransford and Sears (2005) have proposed that transferring knowledge into a situation may differ from transferring knowledge out to a situation as a means to reconcile fndings that transfer may both be frequent and challenging to promote.[53] A signifcant and long research history has also attempted to explicate the conditions under which transfer of learning might occur. Early research by Ruger, for example, found that the "level of attention", "attitudes", "method of attack" (or method for tackling a problem), a "search for new points of view", "a careful testing of hypothesis" and "generalization" were all valuable approaches for promoting transfer.[54] To encourage transfer through teaching, Perkins and Salomon recommend aligning ("hugging") instruction with practice and assessment, and "bridging", or encouraging learners to refect on past experiences or make connections between prior knowledge and current content.[51] Factors affecting learning External factors. Heredity: A classroom instructor can neither change nor increase heredity, but the student can use and develop it. Some learners are rich in hereditary endowment while others are poor. Each student is unique and has different abilities. Te native intelligence is different in individuals. Heredity governs or conditions our ability to learn and the rate of learning. Te intelligent learners can establish and see relationship very easily and more quickly. Status of students: Physical and home conditions also matter: Certain problems like malnutrition i.e.; inadequate supply of nutrients to the body, fatigue i.e.; tiredness, bodily weakness, and bad health are great obstructers in learning. Tese are some of the physical conditions by which a student can get affected. Home is a place where a family lives. If the home conditions are not proper, the student is affected seriously. Some of the home conditions are bad ventilation, unhygienic living, bad light, etc. Tese affect the student and his or her rate of learning. Physical environment: Te design, quality, and setting of a learning space, such as a school or classroom, can each be critical to the success of a learning environment. Size, confguration, comfort—fresh air, temperature, light, acoustics, furniture—can all affect a student's learning. Te tools used by both instructors and students directly affect how information is conveyed, from display and writing surfaces (blackboards, markerboards, tack surfaces) to digital technologies. For example, if a room is too crowded, 22 stress levels rise, student attention is reduced, and furniture arrangement is restricted. If furniture is incorrectly arranged, sight lines to the instructor or instructional material is limited and the ability to suit the learning or lesson style is restricted. Aesthetics can also play a role, for if student morale suffers, so does motivation to attend school.[57][58]Tere are several internal factors that affect learning.[59][60] Tey are Goals or purposes: Each and everyone has a goal. A goal should be set to each pupil according to the standard expected to him. A goal is an aim or desired result. Tere are 2 types of goals called immediate and distant goals. A goal that occurs or is done at once is called an immediate goal, and distant goals are those that take time to achieve. Immediate goals should be set before the young learner and distant goals for older learners. Goals should be specifc and clear, so that learners understand. Motivational behavior: Motivation means to provide with a motive. Motivation learners should be motivated so that they stimulate themselves with interest. Tis behavior arouses and regulates the student's internal energies. Interest: Tis is a quality that arouses a feeling. It encourages a student to move over tasks further. During teaching, the instructor must raise interests among students for the best learning. Interest is an apparent (clearly seen or understood) behaviour. Attention: Attention means consideration. It is concentration or focusing of consciousness upon one object or an idea. If effective learning should take place attention is essential. Instructors must secure the attention of the student. Drill or practice: Tis method includes repeating the tasks "n" number of times like needs, phrases, principles, etc. Tis makes learning more effective. Fatigue: Generally there are three types of fatigue, i.e., muscular, sensory, and mental. Muscular and sensory fatigues are bodily fatigue. Mental fatigue is in the central nervous system. Te remedy is to change teaching methods, e.g., use audio- visual aids, etc. Aptitude: Aptitude is natural ability. It is a condition in which an individuals ability to acquire certain skills, knowledge through training. Attitude: It is a way of thinking. Te attitude of the student must be tested to fnd out how much inclination he or she has for learning a subject or topic. Emotional conditions: Emotions are physiological states of being. Students who answer a question properly or give good results should be praised. Tis encouragement increases their ability and helps them produce better results. Certain attitudes, such as always fnding fault in a student's answer or provoking or embarrassing the student in front of a class are counterproductive. Speed, Accuracy and retention: Speed is the rapidity of movement. Retention is the act of retaining. Tese 3 elements depend upon aptitude, attitude, interest, attention and motivation of the students. Learning activities: Learning depends upon the activities and experiences provided by the teacher, his concept of discipline, methods of teaching and above all his overall personality. Testing: Various tests measure individual learner differences at the heart of effective learning. Testing helps eliminate subjective elements of measuring pupil differences and performances. Guidance: Everyone needs guidance in some part or some time in life. Some need it constantly and some very rarely depending on the students conditions. Small learners need more guidance. Guidance is an advice to solve a problem. Guidance involves the art of helping boys and girls in various aspects of academics, improving vocational aspects like choosing careers and recreational aspects like choosing hobbies. Guidance covers the whole gamut of learners problems- learning as well as non- learning. Epigenetics in learning and memory. Te underlying molecular basis of learning appears to be dynamic changes in gene expression occurring in brain neurons that are introduced by epigenetic mechanisms. Epigenetic regulation of gene expression involves, most notably, chemical modifcation of DNA or DNA-associated histone proteins. Tese chemical modifcations can cause long lasting changes in gene expression. Epigenetic mechanisms involved in learning include the methylation and demethylation of neuronal DNA as well as methylation, acetylation and deacetylation of neuronal histone proteins. During learning, information processing in the brain involves induction of oxidative modifcation in neuronal DNA followed by the employment of DNA repair processes that introduce epigenetic alterations. In particular, the DNA repair processes of non-homologous end joining and base excision repair are employed in learning and memory formation. [61][62] In animal evolution .Animals gain knowledge in two ways. First is learning—in which an animal gathers information about its environment and uses this information. For example, if an animal eats something that hurts its stomach, it learns not to eat that again. Te second is innate knowledge that is genetically inherited. An example of this is when a horse is born and can immediately walk. Te horse has not learned this behavior; it simply knows how to do it.[63] In some scenarios, innate knowledge is more benefcial than learned knowledge. However, in other scenarios the opposite is true—animals must learn certain behaviors when it is disadvantageous to have a specifc innate behavior. In these situations, learning evolves in the species. Costs and benefts of learned and innate knowledge. In a changing environment, an animal must constantly gain new information to survive. However, in a stable environment, this same individual needs to gather the information it needs once, and then rely on it for the rest of its life. Terefore, different scenarios better suit either learning or innate knowledge. Essentially, the cost of obtaining certain knowledge versus the beneft of already having it determines whether an animal evolved to learn in a given situation, or whether it innately knew the information. If the cost of gaining the knowledge outweighs the beneft of having it, then the animal does not evolve to learn in this scenario—but instead, non-learning

23 evolves. However, if the beneft of having certain information outweighs the cost of obtaining it, then the animal is far more likely to evolve to have to learn this information.

Non-learning is more likely to evolve in two scenarios. If an environment is static and change does not or rarely occurs, then learning is simply unnecessary. Because there is no need for learning in this scenario—and because learning could prove disadvantageous due to the time it took to learn the information—non-learning evolves. However, if an environment is in a constant state of change, then learning is disadvantageous. Anything learned is immediately irrelevant because of the changing environment.[63] Te learned information no longer applies. Essentially, the animal would be just as successful if it took a guess as if it learned. In this situation, non-learning evolves. In fact, a study of Drosophila melanogaster showed that learning can actually lead to a decrease in productivity, possibly because egg-laying behaviors and decisions were impaired by interference from the memories gained from the new learned materials or because of the cost of energy in learning.[64] However, in environments where change occurs within an animal's lifetime but is not constant, learning is more likely to evolve. Learning is benefcial in these scenarios because an animal can adapt to the new situation, but can still apply the knowledge that it learns for a somewhat extended period of time. Terefore, learning increases the chances of success as opposed to guessing.[63] An example of this is seen in aquatic environments with landscapes subject to change. In these environments, learning is favored because the fsh are predisposed to learn the specifc spatial cues where they live.[65] In plants; In recent years, plant physiologists have examined the physiology of plant behavior and cognition. Te concepts of learning and memory are relevant in identifying how plants respond to external cues, a behavior necessary for survival. Monica Gagliano, an Australian professor of evolutionary ecology, makes an argument for associative learning in the garden pea, Pisum sativum. Te garden pea is not specifc to a region, but rather grows in cooler, higher altitude climates. Gagliano and colleagues’ 2016 paper aims to differentiate between innate phototropism behavior and learned behaviors.[21] Plants use light cues in various ways, such as to sustain their metabolic needs and to maintain their internal circadian rhythms. Circadian rhythms in plants are modulated by endogenous bioactive substances that encourage leaf-opening and leaf-closing and are the basis of nyctinastic behaviors.[66] Gagliano and colleagues constructed a classical conditioning test in which pea seedlings were divided into two experimental categories and placed in Y-shaped tubes.[21] In a series of training sessions, the plants were exposed to light coming down different arms of the tube. In each case, there was a fan blowing lightly down the tube in either the same or opposite arm as the light. Te unconditioned stimulus (US) was the predicted occurrence of light and the conditioned stimulus (CS) was the wind blowing by the fan. Previous experimentation shows that plants respond to light by bending and growing towards it through differential cell growth and division on one side of the plant stem mediated by auxin signalling pathways.[67] During the testing phase of Gagliano's experiment, the pea seedlings were placed in different Y-pipes and exposed to the fan alone. Teir direction of growth was subsequently recorded. Te ‘correct’ response by the seedlings was deemed to be growing into the arm where the light was “predicted” from the previous day. Te majority of plants in both experimental conditions grew in a direction consistent with the predicted location of light based on the position of the fan the previous day.[21] For example, if the seedling was trained with the fan and light coming down the same arm of the Y-pipe, the following day the seedling grew towards the fan in the absence of light cues despite the fan being placed in the opposite side of the Y-arm. Plants in the control group showed no preference to a particular arm of the Y-pipe. Te percentage difference in population behavior observed between the control and experimental groups is meant to distinguish innate phototropism behavior from active associative learning.[21] While the physiological mechanism of associative learning in plants is not known, Telewski et al. describes a hypothesis that describes photoreception as the basis of mechano-perception in plants.[68] One mechanism for mechano-perception in plants relies on MS ion channels and calcium channels. Mechanosensory proteins in cell lipid bilayers, known as MS ion channels, are activated once they are physically deformed in response to pressure or tension. Ca2+ permeable ion channels are “stretch- gated” and allow for the infux of osmolytes and calcium, a well-known second messenger, into the cell. Tis ion infux triggers a passive fow of water into the cell down its osmotic gradient, effectively increasing turgor pressure and causing the cell to depolarize.[68] Gagliano hypothesizes that the basis of associative learning in Pisum sativum is the coupling of mechanosensory and photosensory pathways and is mediated by auxin signaling pathways. Te result is directional growth to maximize a plant's capture of sunlight.[21] Gagliano et al. published another paper on habituation behaviors in the mimosa pudica plant whereby the innate behavior of the plant was diminished by repeated exposure to a stimulus.[13] Tere has been controversy around this paper and more generally around the topic of plant cognition. Charles Abrahmson, a psychologist and behavioral biologist, says that part of the issue of why scientists disagree about whether plants have the ability to learn is that researchers do not use a consistent defnition of "learning" and "cognition".[69] Similarly, Michael Pollan, an author and journalist, says in his piece Te Intelligent Plant that researchers do not doubt Gagliano's data but rather her language, specifcally her use of the term “learning” and "cognition" with respect to plants.[70] A direction for future research is testing whether circadian rhythms in plants modulate learning and behavior and surveying researchers' defnitions of “cognition” and “learning.”

24 Evolution is the process that led to the emergence, development and learning deliberated through history, with a future outlook – in particular, people – often leading too development of language. Flux and state change alter through the ages, between these years, particularly philosophy, theology and religion interpret god and interrelate the evolution of life on a planet. Revolutions can reset organisation of structure too god’s intended purpose, for example particularly political, socialist states are primal and are the fnest example of politic.

Te study of human evolution involves many scientifc disciplines, including physical anthropology, primatology, archaeology, paleontology, neurobiology, ethology, linguistics, evolutionary psychology, embryology, genetics and others. DNA is the bodies hard core code that can be updated via RNA is for healing purposes and intelligence. And ONA is oxygen intelligence; again for example if people pollute the air, we are automatically devolving.

Life is a characteristic that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not- is a computer alive? , either because such functions have ceased (they have died), or because they never had such functions and are classifed as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. Te criteria can at times be ambiguous and may or may not defne viruses, viroids, or potential synthetic life as "living". Biology is the science concerned with the study of life.

Tere is currently no consensus regarding the defnition of life. One popular defnition is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to stimuli, reproduce and evolve. However, several other defnitions have been proposed, and there are some borderline cases of life, such as viruses or viroids.

Since its primordial beginnings, life on Earth has changed its environment on a geologic time scale, but it has also adapted to survive in most ecosystems and conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth. Te cell is considered the structural and functional unit of life originally atomics. Tere are 14 types of cells, prokaryotic and eukaryotic foremost kinds, both of which consist of cytoplasm enclosed within a membrane and contain many biomolecules such as proteins and nucleic acids. Cells reproduce through a process of cell division, in which the parent cell divides into two or more daughter cells.

In the past, there have been many attempts to defne what is meant by "life" through obsolete concepts such as odic force, hylomorphism, spontaneous generation and vitalism, that have now been disproved by biological discoveries. Aristotle was the frst person to classify organisms. Later, Carl Linnaeus introduced his system of binomial nomenclature for the classifcation of species. Eventually new groups and categories of life were discovered, such as cells and microorganisms, forcing dramatic revisions of the structure of relationships between living organisms. Tough currently only known on Earth, life need not be restricted to it, and many scientists speculate in the existence of extraterrestrial life. Artifcial life is a computer simulation or man-made reconstruction of any aspect of life, which is often used to examine systems related to natural life.

In the past, before modern technology largely alleviated issues of economic scarcity in industrialised countries, most people spent a large portion of their time attempting to provide their basic survival needs, including water, food, and protection from the weather. Humans needed survival skills for the sake of both themselves and their community; food needed to be harvested and shelters needed to be maintained. Tere was little privacy in a community, and people identifed one another according to their social role. Jobs were assigned out of necessity rather than personal choice.

Furthermore, individuals in many ancient cultures primarily viewed their self-existence under the aspect of a larger social whole, often one with mythological underpinnings which placed the individual in relation to the cosmos. People in such cultures found their identity not through their individual choices— indeed, they may not have been able to conceive a choice which was purely individual. Such individuals, if asked to describe themselves, would speak of the collective of which they were part: the tribe, the Church, the nation. Even in the 21st century, survival issues dominate in many countries and societies. For example, the continents of Africa and Asia are still largely mired in poverty and third-world conditions, without technology, secure shelter, or reliable food sources. In such places, the concepts of a "personal life", "self- actualization", "personal fulfllment", or "privacy" are often unaﬀordable luxuries.

Te English philosopher John Locke (1632-1704) fgures among the pioneers in discussing the concept of individual rights. In the 17th century he promoted the natural rights of the individual to life, liberty, and property, and included the pursuit of happiness as one of the individual's goals.

25 Everyday life, daily life or routine life comprises the ways in which people typically act, think, and feel on a daily basis. Everyday life may be described as mundane, routine, natural, habitual, or normal.

Human diurnality means most people sleep at least part of the night and are active in daytime. Most eat two or three meals in a day. Working time (apart from shift work) mostly involves a daily schedule, beginning in the morning. Tis produces the daily rush hours experienced by many millions, and the drive time focused on by radio broadcasters. Evening is often leisure time. Bathing every day is a custom for many.

Beyond these broad similarities, lifestyles vary and different people spend their days differently. Nomadic life differs from sedentism, and among the sedentary, urban people live differently from rural folk. Differences in the lives of the rich and the poor, or between factory workers and intellectuals, may go beyond their working hours. Many women spend their day in activities greatly different from those of men, and everywhere children do different things than adults.

Everyday life is a key concept in cultural studies and is a specialized subject in the feld of sociology. Some argue that, motivated by capitalism and industrialism's degrading eﬀects on human existence and perception, writers and artists of the 19th century turned more towards self-refection and the portrayal of everyday life represented in their writings and art to a noticeably greater degree than in past works, for example Renaissance literature's interest in hagiography and politics. Other theorists dispute this argument based on a long history of writings about daily life which can be seen in works from Ancient Greece, medieval Christianity and the Age of Enlightenment.

In the study of everyday life gender has been an important factor in its conceptions. Some theorists regard women as the quintessential representatives and victims of everyday life. Yet what is the victim syndrome of being male, macho in the wrong places wanting too protect when friendship was meeted lack of soft qualities further,ego without egalitarian fnally lack of love and understanding of womanly nature and motherly tendency.

Te connotation of everyday life is often negative and is distinctively separated from exceptional moments by its lack of distinction and diﬀerentiation, ultimately defned as the essential, taken-for-granted continuum of mundane activity that outlines forays into more esoteric experiences. It is the non-negotiable reality that exists amongst all social groupings without discrimination and is an unavoidable basis for which all human endeavor exists. Pray often to heal timing cycles of mundane expereince the more you pray - at any age the more you return to life in the fullest.

In other words Psient is trying to say that life always goes on and on and on and on and always changes through given processes, this is true evolution and a miracle. Tanks be too God, how does he do it!

Tere are other miracles, usually only these can be summoned via prayer or worship; prayers of healing are one example.

26 4) Teology and Religion

God embodies you and everything else, with prayer he will them tell you more answers. God is one so are you. God through the ages has had many names and speaks all languages known; the name the creator designates as himself is God, this translates too different names in different languages with different Prophets and Orders. When Psient debates one or more god’s it is not debating whether there is another or other God, Psient believes in one “God’’ his own name for himself.

Teology translates into English from the Greek theologia (θεολογία) which derived from Τheos (Θεός), meaning "God," and -logia (- λογία),meaning "utterances, sayings, or oracles" (a word related to logos [λόγος], meaning "word, discourse, account, or reasoning") which had passed into Latin as theologia and into French as théologie. Te English equivalent "theology" (Teologie, Teologye) had evolved by 1362] Te sense the word has in English depended in a large part on the sense the Latin and Greek equivalents had acquired in patristic and medieval Christian usage, although the Banoshie term has now spread beyond Christian contexts.

Scripture must be written by scribes. Religious texts (also known as scripture, or scriptures, from the Latin scriptura, meaning "writing") are texts which religious traditions consider to be central to their practice or beliefs. Religious texts may be used to provide meaning and purpose, evoke a deeper connection with the divine, convey religious truths, promote religious experience, foster communal identity, and guide individual and communal religious practice. Religious texts often communicate the practices or values of a religious traditions and can be looked too as a set of guiding principles which dictate physical, mental, spiritual, or historical elements considered important to a specifc religion. Te terms 'sacred' text and 'religious' text are not necessarily interchangeable in that some religious texts are believed to be sacred because of their nature as divinely or supernaturally revealed or inspired, whereas some religious texts are simply narratives pertaining to the general themes, practices, or important fgures of the specifc religion, and not necessarily considered sacred by itself. A core function of a religious text making it sacred is its ceremonial and liturgical role, particularly in relation to sacred time, the liturgical year, the divine eﬃcacy and subsequent holy service; in a more general sense, its performance and celebration.

Righteousness is defned as "the quality of being morally correct and justifable. It can also be considered synonymous with “rightness" - “truth telling” It is a concept that can be found in Dharmic traditions and Abrahamic traditions as a theological concept. For example, from various perspectives in Hinduism, Christianity, and Judaism it is considered an attribute that implies that a person's actions are justifed, and can have the connotation that the person has been "judged" or "reckoned" as leading a life that is pleasing to God.

It is not possible to create an exhaustive list of religious texts, because there is no single defnition of which texts are recognized as religious. Also and there are probably too many too mention, but could feisably be done, these texts number around 48 billion documents.

Augustine of Hippo defned the Latin equivalent, theologia, as "reasoning or discussion concerning the Deity"; Richard Hooker defned "theology" in English as "the science of things divine". Te term can, however, be used for a variety of diﬀerent disciplines or felds of study. Do not mix science into religion, theology can cross barriers.

Teology begins with the assumption that the divine exists in form and function within people as godly discussion and debate; such as in physical, supernatural, mental, or social realities, and that evidence for and about it may be found via personal spiritual experiences and/or historical records of such experiences as documented by others for digest. Te study of these assumptions is not part of theology proper but is found in the philosophy of religion, and increasingly though the psychology of religion and neurotheology. Teology then aims to structure and understand these experiences and concepts, and to use them to derive normative prescriptions for how to live our lives.

Teologians use various forms of analysis and argument (experiential, philosophical, ethnographic, historical, and others) to help understand, explain, test, critique, defend or promote any of myriad religious topics. As in philosophy of ethics and case law, arguments often assume the existence of previously resolved questions, and develop by making analogies from them to draw new inferences in new situations.

Te study of theology may help a theologian more deeply understand their own religious tradition, another religious tradition, or it may enable them to explore the nature of divinity without reference to any specifc tradition. Teology may be used to propagate, reform, or justify a religious tradition or it may be used to compare, challenge (e.g. criticism), or oppose (e.g. irreligion) a religious tradition or world-view. Teology might also help a theologian to address some present situation or need through a religious tradition, or to explore possible ways of interpreting the world.

27 Tere is no scholarly consensus over what precisely constitutes a religion.It may be defned as a cultural system of designated behaviors and practices, world views, texts, sanctifed places, prophesies, ethics, or organizations, that relate humanity to the supernatural, transcendental, or spiritual.

Diﬀerent religions may or may not contain various elements ranging from the divine, sacred things, faith, a supernatural being or supernatural beings or "some sort of ultimacy and transcendence that will provide norms and power for the rest of life". Religious practices may include rituals, sermons, commemoration or veneration (of deities), sacrifces, festivals, feasts, trances, initiations, funerary services, matrimonial services, meditation, prayer, music, art, dance, public service, or other aspects of human culture. Religions have sacred histories and narratives, which may be preserved in sacred scriptures, and symbols and holy places, that aim mostly to give a meaning to life. Religions may contain symbolic stories, which are sometimes said by followers to be true, that have the side purpose of explaining the origin of life, the Universe and other things. Traditionally, faith, in addition to reason, has been considered a source of religious beliefs.

Tere are an estimated 14,000 distinct religions worldwide, at millennium 4% Abran about 84% of the world's population is affiliated with one of the fve largest religions, namely Christianity, Islam, Hinduism, Buddhism or forms of folk spirituality. Te religiously unaffiliated demographic includes those who do not identify with any particular religion, atheists and agnostics. While the religiously unaffiliated have grown globally, many of the religiously unaffiliated still have various religious beliefs.

Te study of religion encompasses a wide variety of academic disciplines, including theology, comparative religion and social scientifc studies. Teories of religion oﬀer various explanations for the origins and workings of religion.

A creation myth (or cosmogonic myth) is a symbolic narrative of how the world began and how people frst came to inhabit it. While in popular usage the term myth often refers to false or fanciful stories, members of cultures often ascribe varying degrees of truth to their creation myths. In the society in which it is told, a creation myth is usually regarded as conveying profound truths, metaphorically, symbolically and sometimes in a historical or literal sense. Tey are commonly, although not always, considered cosmogonical myths – that is, they describe the ordering of the cosmos from a state of chaos or amorphousness.

Creation myths often share a number of features. Tey often are considered sacred accounts and can be found in nearly all known religious traditions. Tey are all stories with a plot and characters who are either deities, human-like fgures, or animals, who often speak and transform easily. Tey are often set in a dim and nonspecifc past that historian of religion Mircea Eliade termed in illo tempore ("at that time"). Creation myths address questions deeply meaningful to the society that shares them, revealing their central worldview and the framework for the self-identity of the culture and individual in a universal context.

Creation myths develop in oral traditions and therefore typically have multiple versions; found throughout human culture, they are the most common form of myth.

Mythology refers variously to the collected myths of a group of people or to the study of such myths. For example King Arthur and Merlin are myths.

Myth is a feature of every culture. Many sources for myths have been proposed, ranging from personifcation of nature or personifcation of natural phenomena, to truthful or hyperbolic accounts of historical events to explanations of existing rituals. A culture's collective mythology helps convey belonging, shared and religious experiences, behavioral models, and moral and practical lessons.

Te study of myth began in ancient history. Rival classes of the Greek myths by Euhemerus, Plato and Sallustius were developed by the Neoplatonists and later revived by Renaissance mythographers. Te nineteenth-century comparative mythology reinterpreted myth as a primitive and failed counterpart of science (Tylor), a "disease of language" (Müller), or a misinterpretation of magical ritual (Frazer).

Recent approaches often view myths as manifestations of psychological, cultural, or societal truths, rather than as inaccurate historical accounts. A myth is a traditional story consisting of events that are ostensibly historical, though often supernatural, explaining the origins of a cultural practice or natural phenomenon.Te word "myth" is derived from the Greek word mythos (μῦθος), which simply means "story". Mythology can refer either to the study of myths, or to a body or collection of myths. Myth can mean 'sacred story', 'traditional narrative' or 'tale of the gods'. A myth can also be a story to explain why something exists.

28 Human cultures' mythologies usually include a cosmogonical or creation myth, concerning the origins of the world, or how the world came to exist. Te active beings in myths are generally gods and goddesses, heroes and heroines, or animals and plants. Most myths are set in a timeless past before recorded time or beginning of the critical history. A myth can be a story involving symbols that are capable of multiple meanings.

A myth is a sacred narrative because it holds religious or spiritual signifcance for those who tell it. Myths also contribute to and express a culture's systems of thought and values.

In monotheistic thought, God is believed to be the Supreme Being and the principal object of faith. Te concept of God, as described by theologians, commonly includes the attributes of omniscience (all-knowing), omnipotence (unlimited power), omnipresence (present everywhere), divine simplicity, and as having an eternal and necessary existence.

God is most often held to be incorporeal (immaterial), and to be without gender, although many religions describe God using masculine terminology, using such terms as "Him" or "Father" and some religions (such as Judaism) attribute only a purely grammatical "gender" to God.[Incorporeity and corporeity of God are related to conceptions of transcendence (being outside nature) and immanence (being in nature, in the world) of God, with positions of synthesis such as the "immanent transcendence".

God has been conceived as either personal or impersonal. In theism, God is the creator and sustainer of the universe, while in deism, God is the creator, but not the sustainer, of the universe. God has also been conceived as the source of all moral obligation, and the "greatest conceivable existent".Many notable philosophers have developed arguments for and against the existence of God.

Te many diﬀerent conceptions of God, and competing claims as to God's characteristics, aims, and actions, have led to the development of ideas of omnitheism, pandeism, or a perennial philosophy, which postulates that there is one underlying theological truth, of which all religions express a partial understanding, and as to which "the devout in the various great world religions are in fact worshipping that one God, but through diﬀerent, overlapping concepts or mental images of Him."

What is preferred and what is more accurate is that each prophet brings along they’re own god with a name; for example in Abran it is God in Islam it is Allah, yet Allah was run by God;. God is his own name for himself.

Tere are many names for God, and diﬀerent names are attached to diﬀerent cultural ideas about God's identity and attributes. In the ancient Egyptian era of Atenism, possibly the earliest recorded monotheistic religion, this deity was called Aten, premised on being the one "true" Supreme Being and creator of the universe’s, heaven and hell. In the Hebrew Bible traditionally interpreted as ,יהוה :and Judaism, "He Who Is", "I Am that I Am", and the tetragrammaton YHWH (Hebrew "I am who I am"; "He Who Exists") are used as names of God, while Yahweh and Jehovah are sometimes used in Christianity as vocalizations of YHWH. In the Christian doctrine of the Trinity, God, consubstantial in three persons, is called the Father, the Son, and the Holy Spirit. In Judaism, it is common to refer to God by the titular names Elohim or Adonai. In Islam, the name Allah is used, while Muslims also have a multitude of titular names for God. In Hinduism, Brahman is often considered a monistic concept of God. In Chinese religion, God (Shangdi) is conceived as the progenitor (frst ancestor) of the universe, intrinsic to it and constantly ordaining it. Other religions have names for God, for instance, Baha in the Bahá'í Faith, Waheguru in Sikhism, and Ahura Mazda in Zoroastrianism. God is his own name for himself.

Compassion motivates people to go out of their way to help the physical, mental or emotional pains of another and themselves. Compassion is often regarded as having sensitivity, an emotional aspect to suffering, though when based on cerebral notions such as fairness, justice, and interdependence, it may be considered rational in nature and its application understood as an activity also based on sound judgment. Tere is also an aspect of equal dimension, such that individual's compassion is often given a property of "depth", "vigour", or "passion". Te etymology of "compassion" is Latin, meaning "co-suffering." Compassion involves "feeling for another" and is a precursor to empathy, the "feeling as another" capacity for better person centered acts of active compassion, in common parlance active compassion is the desire to alleviate another's suffering.

Compassion involves allowing ourselves to be moved by suffering, and experiencing the motivation to help alleviate and prevent it. An act of compassion is defned by its helpfulness. Qualities of compassion are patience and wisdom; kindness and perseverance; warmth and resolve. It is often, though not inevitably, the key component in what manifests in the social context as altruism. Expression of compassion is prone to be hierarchical, paternalistic and controlling in responses. Difference between sympathy and compassion is that the former responds to suffering with sorrow and concern while the latter responds with warmth and care.

29 Te Banoshie noun compassion, meaning to love together with, comes from Latin. Its prefx com- comes directly from com, an archaic version of the Latin preposition and affix cum (= with); the -passion segment is derived from passus, past participle of the deponent verb patior, patī, passus sum. Compassion is thus related in origin, form and meaning to the English noun patient (= one who suffers), from patiens, present participle of the same patior, and is akin to the Greek verb πάσχειν (= paskhein, to suffer) and to its cognate noun πάθος (= pathos). Ranked a great virtue in numerous philosophies, compassion is considered in almost all the major religious traditions as among the greatest of virtues.

Religious Hope is a belief in state of mind that is based on an expectation of positive outcomes with respect to events and circumstances in one's life or the world at large. As a verb, its defnitions include: "expect with confdence" and "to cherish a desire with anticipation”. Among its opposites are dejection, hopelessness and despair.

A spirit is a supernatural being, often but not exclusively a non-physical entity; such as a ghost, fairy, or angel. Te concepts of a person's spirit and soul, often also overlap, as both are either contrasted with or given ontological priority over the body and both are believed to survive bodily death in some religions, and "spirit" can also have the sense of "ghost", i.e. a manifestation of the spirit of a deceased person. Spirit is often used metaphysically to refer to the consciousness or personality.

Historically, it was also used to refer to a "subtle" as opposed to "gross" material substance, as in the famous last paragraph of Sir Isaac Newton's Principia Mathematica.

Te English word "spirit" comes from the Latin spiritus, meaning "breath", but also "spirit, soul, courage, vigor", ultimately from a Proto-Indo-European *(s)peis. It is distinguished from Latin anima, "soul" (which nonetheless also derives from an Indo-European root meaning "to breathe", earliest for. In Greek, this distinction exists between pneuma (πνεῦμα), "breath, motile air, spirit," and psykhē (ψυχή), "soul" (even though the latter term, ψῡχή = psykhē/ psūkhē, is also from an Indo- European root meaning "to breathe": *bhes-, zero grade *bhs- devoicing in proto-Greek to *phs-, resulting in historical- Te word "spirit" came into Middle )نفس( .("period Greek ps- in psūkhein, "to breathe", whence psūkhē, "spirit", "soul English via Old French. Te distinction between soul and spirit also developed in the Abrahamic religions: Arabic nafs népē š (in Hebrew neshama comes from the root שֶנֶ֫פ nəšâmâh) or nephesh נְשָמָה) Hebrew neshama ;(روح) opposite rūħ NŠM or "breath") opposite ruach rúaħ). (Note, however, that in Semitic just as in Indo-European, this dichotomy has not and (נפש root) שֶנֶ֫פ long period of development: Both )רוחַ always been as neat historically as it has come to be taken over a as well as cognate words in various Semitic languages, including Arabic, also preserve meanings involving ,(רוח root) רוחַ misc. air phenomena: "breath", "wind", and even “aroma").

In many religious, philosophical and mythological traditions, there is a belief in the incorporeal essence of a living being called the soul.

Soul or psyche (Greek: "psyühē", of "psychein", "to breathe") are the mental abilities of a living being: reason, character, feeling, consciousness, memory, perception, thinking, etc.

Psychopomps (from the Greek word ψυχοπομπός, psuchopompos, literally meaning the "guide of souls")[1] are creatures, spirits, angels, or deities in many religions whose responsibility is to escort newly deceased souls from Earth to the afterlife. Teir role is not to judge the deceased, but simply to provide safe passage. Appearing frequently on funerary art, psychopomps have been depicted at diﬀerent times and in diﬀerent cultures as anthropomorphic entities, horses, deer, dogs, whip-poor-wills, ravens, crows, owls, sparrows and cuckoos. When seen as birds, they are often seen in huge masses, waiting outside the home of the dying.

Depending on the philosophical system, a soul can either be mortal or immortal. In Judeo-Christianity, only human beings have immortal souls (although immortality is disputed within Judaism and may have been infuenced by Plato, and in Eastern Orthodox Christianity the soul is said to be immortal by grace, but not nature). For example, the Catholic theologian Tomas Aquinas attributed "soul" (anima) to all organisms but argued that only human souls are immortal. Other religions (most notably Hinduism and Jainism) hold that all biological organisms have souls (atman, jiva) and a 'vital principle' (prana), as did Aristotle. Some teach that even non-biological entities (such as rivers and mountains) possess souls.

Greek philosophers, such as Socrates, Plato, and Aristotle, understood that the soul (ψυχή psūchê) must have a logical faculty, the exercise of which was the most divine of human actions. At his defense trial, Socrates even summarized his teaching as nothing other than an exhortation for his fellow Athenians to excel in matters of the psyche since all bodily goods are dependent on such excellence.

30 Anima mundi is the concept of a "world soul" connecting all living organisms on planet Earth.

An angel is generally a supernatural being found in various religions and mythologies. In Abrahamic religions and Zoroastrianism, angels are often depicted as benevolent celestial beings who act as intermediaries between God or Heaven and Earth. Other roles of angels include protecting and guiding human beings, and carrying out God's tasks. Within Abrahamic religions, angels are often organized into hierarchies, although such rankings may vary between sects in each religion, and are given specifc names or titles, such as Gabriel or "Destroying angel". Te term "angel" has also been expanded to various notions of spirits or fgures found in other religious traditions. Te theological study of angels is known as “angelology".

In fne art, angels are usually depicted as having the shape of human beings of extraordinary beauty; they are often identifed using the symbols of bird wings, halos, and light.

A halo (from Greek ἅλως, halōs; also known as a nimbus, aureole, glory, or gloriole) is a crown of light rays, circle or disk of light that surrounds a person in art. Tey have been used in the iconography of many religions to indicate holy or sacred fgures, and have at various periods also been used in images of rulers or heroes. In the sacred art of Ancient Greece, Ancient Rome, Hinduism, Buddhism, Islam and Christianity, among other religions, sacred persons may be depicted with a halo in the form of a circular glow, or fames in Asian art, around the head or around the whole body—this last one is often called a mandorla. Halos may be shown as almost any colour or combination of colours, but are most often depicted as golden, yellow or white when representing light or red when representing fames.

Freedom, generally, is having an ability to act or change without constraint. A thing is "free" if it can change its state easily and is not constrained in its present state. In philosophy and religion, it is associated with having free will and being without undue or unjust constraints, or enslavement, and is an idea closely related to the concept of liberty. A person has the freedom to do things that will not, in theory or in practice, be prevented by other forces. Outside of the human realm, freedom generally does not have this political or psychological dimension. A rusty lock might be oiled so that the key has freedom to turn, undergrowth may be hacked away to give a newly planted sapling freedom to grow, or a mathematician may study an equation having many degrees of freedom.

Virtue (Latin: virtus, Ancient Greek: ἀρετή "arete") is moral excellence. A virtue is a trait or quality that is deemed to be morally good and thus is valued as a foundation of principle and good moral being. Personal virtues are characteristics valued as promoting collective and individual greatness. Te opposite of virtue is vice.

Te four classic cardinal virtues are temperance, prudence, courage, and justice. Christianity derives the three theological virtues of faith, hope and love (charity) from 1 Corinthians. Together these make up the seven virtues. Buddhism's four brahmavihara ("Divine States") can be regarded as virtues in the European sense.

Te Japanese Bushidō code is characterized by up to ten virtues, including rectitude, courage, and benevolence.

In spiritual terminology, piety is a virtue that may include religious devotion, spirituality, or a mixture of both. A common element in most conceptions of piety is humility and religiosity.

Humility is the quality of being humble. In a religious context humility can mean a recognition of self in relation to a deity (i.e.God) or deities, and self-debasement with subsequent submission to said deity as a member of that religion. Outside of a religious context, humility is defned as being "unselved" a liberation from consciousness of self, a form of temperance that is neither having pride (or haughtiness) nor indulging in self-deprecation. Te materialistic view characterizes humility as self- restraint that frees oneself from vanity.

Humility is an outward expression of an appropriate inner, or self, regard and is contrasted with humiliation which is an imposition, often external, of shame upon a person. Humility may be misappropriated as ability to suﬀer humiliation through self-denouncements which in itself remains focus on self rather than low self-focus.

Humility, in various interpretations, is widely seen as a virtue which centers on low self-preoccupation, or unwillingness to put oneself forward, so it is in many religious and philosophical traditions, it contrasts with narcissism, hubris and other forms of pride and is an idealistic and rare intrinsic construct that has an extrinsic side.

Temperance is defned as moderation or voluntary self-restraint. It is typically described in terms of what an individual voluntarily refrains from doing. Tis includes restraint from retaliation in the form of non-violence and forgiveness, restraint from arrogance in the form of humility and modesty, restraint from excesses such as splurging now in the form of prudence, and restraint from excessive anger or craving for something in the form of calmness and self-control. 31 Prudence (Latin: prudentia, contracted from providentia meaning "seeing ahead, sagacity") is the ability to govern and discipline oneself by the use of reason. It is classically considered to be a virtue, and in particular one of the four Cardinal virtues (which are, with the three theological virtues, part of the seven virtues). Prudentia is an allegorical female personifcation of the virtue, whose attributes are a mirror and snake, who is frequently depicted as a pair with Justitia, the Roman goddess of Justice.

Religiosity is diﬃcult to defne, but diﬀerent scholars have seen this concept as broadly about religious orientations and involvement. It includes experiential, ritualistic, ideological, intellectual, consequential, creedal, communal, doctrinal, moral, and cultural dimensions. Sociologists of religion have observed that the people's beliefs, sense of belonging, and behavior often are not congruent with an individual's actual religious beliefs since there is much diversity in how one can be religious or not.

Te classical virtue of fortitude (andreia, fortitudo) is also translated "courage", but includes the aspects of perseverance and patience.

In the Western tradition, notable thoughts on courage have come from philosophers, Socrates, Plato, Aristotle, Aquinas, and Kierkegaard; in the Eastern tradition, some thoughts on courage were oﬀered by the Tao Te Ching. More recently, courage has been explored by the discipline of psychology.

Te word derives from the 14th-century Old French word prudence, which, in turn, derives from the Latin prudentia meaning "foresight, sagacity". It is often associated with wisdom, insight, and knowledge. In this case, the virtue is the ability to judge between virtuous and vicious actions, not only in a general sense, but with regard to appropriate actions at a given time and place. Although prudence itself does not perform any actions, and is concerned solely with knowledge, all virtues had to be regulated by it. Distinguishing when acts are courageous, as opposed to reckless or cowardly, is an act of prudence, and for this reason it is classifed as a cardinal (pivotal) virtue.

In modern English, the word has become increasingly synonymous with cautiousness. In this sense, prudence names a reluctance to take risks, which remains a virtue with respect to unnecessary risks, but, when unreasonably extended into over-cautiousness, can become the vice of cowardice.

In the Nicomachean Ethics, Aristotle gives a lengthy account of the virtue phronesis (Ancient Greek: φρονησιϛ), traditionally translated as "prudence", although this has become increasingly problematic as the word has fallen out of common usage. More recently φρονησιϛ has been translated by such terms as "practical wisdom", "practical judgment" or "rational choice". Te word joy means a feeling of great pleasure and happiness. What do you think and feel as someone says something and how does this refect in your answer, the phronesis is the manner of discussion, aptitude in your word.

C. S. Lewis saw clear distinction between joy and pleasure and happiness; "I sometimes wonder whether all pleasures are not substitutes for Joy.", and "I call it Joy, which is here a technical term and must be sharply distinguished both from Happiness and Pleasure. Joy (in my sense) has indeed one characteristic, and one only, in common with them; the fact that anyone who has experienced it will want it again... I doubt whether anyone who has tasted it would ever, if both were in his power, exchange it for all the pleasures in the world. But then Joy is never in our power and Pleasure often is."

Te causes of joy have been ascribed to various sources. “When the mind is pure, joy follows like a shadow that never leaves.” Gautama Buddha, "[Joy is] the emotional dimension of the good life, of a life that is both going well and is being lived well."Miroslav Volf "Tis is the true joy in life, the being used for a purpose recognized by yourself as a mighty one; the being thoroughly worn out before you are thrown on the scrap heap; the being a force of Nature instead of a feverish selfsh little clod of ailments and grievances complaining that the world will not devote itself to making you happy." George Bernard Shaw and “Find a place inside where there's joy, and the joy will burn out the pain.” Joseph Campbell.

Oral tradition, or oral lore, is a form of human communication where in knowledge, art, ideas and cultural material is received, preserved and transmitted orally from one generation to another. Te transmission is through speech or song and may include folktales, ballads, chants, prose or verses. In this way, it is possible for a society to transmit oral history, oral literature, oral law and other knowledge across generations without a writing system, or in parallel to a writing system. Indian religions such as Buddhism, Hinduism and Jainism, for example, have used an oral tradition, in parallel to a writing system, to transmit their canonical scriptures, secular knowledge such as Sushruta Samhita, hymns and mythologies from one generation to the next. 32 Oral tradition is information, memories and knowledge held in common by a group of people, over many generations, and it is not same as testimony or oral history. In a general sense, "oral tradition" refers to the recall and transmission of a specifc, preserved textual and cultural knowledge through vocal utterance. As an academic discipline, it refers both to a set of objects of study and a method by which they are studied.

Te study of oral tradition is distinct from the academic discipline of oral history, which is the recording of personal memories and histories of those who experienced historical eras or events. Oral tradition is also distinct from the study of orality defned as thought and its verbal expression in societies where the technologies of literacy (especially writing and print) are unfamiliar to most of the population. A folklore is a type of oral tradition, but knowledge other than folklore has been orally transmitted and thus preserved in human history.

Perennial philosophy (Latin: philosophia perennis), also referred to as Perennialism and perennial wisdom, is a perspective in modern spirituality that views each of the world's religious traditions as sharing a single, metaphysical truth or origin from which all esoteric and exoteric knowledge and doctrine has grown.

Perennialism has its roots in the Renaissance interest in neo-Platonism and its idea of Te One, from which all existence emanates. Marsilio Ficino (1433–1499) sought to integrate Hermeticism with Greek and Jewish-Christian thought, discerning a Prisca theologia which could be found in all ages. Giovanni Pico della Mirandola (1463–94) suggested that truth could be found in many, rather than just two, traditions. He proposed a harmony between the thought of Plato and Aristotle, and saw aspects of the Prisca theologia in Averroes, the Koran, the Cabala and other sources. Agostino Steuco (1497–1548) coined the term philosophia perennis.

A more popular interpretation argues for universalism, the idea that all religions, underneath seeming diﬀerences point to the same Truth. In the early 19th century the Transcendentalists propagated the idea of a metaphysical Truth and universalism, which inspired the Unitarians, who proselytized among Indian elites. Towards the end of the 19th century, the Teosophical Society further popularized universalism, not only in the western world, but also in western colonies. In the 20th century universalism was further popularized in the English-speaking world through the neo-Vedanta inspired Traditionalist School, which argues for a metaphysical, single origin of the orthodox religions, and by Aldous Huxley and his book Te Perennial Philosophy, which was inspired by neo- Vedanta and the Traditionalist School.

Universalism is a theological and philosophical concept that some ideas have universal application or applicability. A community that calls itself universalist may emphasize the universal principles of most religions and accept other religions in an inclusive manner, believing in a universal reconciliation between humanity and the divine. For example, some forms of Abrahamic religions claim the universal value of their doctrine and moral principles, and "feel inclusive". Christian Universalism is focused around the idea of universal reconciliation, also known as universal salvation — the doctrine that every human soul will ultimately be reconciled to God because of divine love and mercy. A belief in one fundamental truth is also another important tenet. Te living truth is seen as more far-reaching than national, cultural, or religious boundaries or interpretations of that one truth. As the Rig Veda states, “Truth is one; sages call it by various names.” Unitarian Universalism emphasizes that religion is a universal human quality and focuses on the universal principles of most religions. It accepts all religions in an inclusive manner.

Belief is the state of mind in which a person thinks something to be the case with or without there being empirical evidence to prove that something is the case with factual certainty. Another way of defning belief sees it as a mental representation of an attitude positively oriented towards the likelihood of something being true. In the context of Ancient Greek thought, two related concepts were identifed with regards to the concept of belief: pistis and doxa. Simplifed, we may say that pistis refers to "trust" and "confdence", while doxa refers to "opinion" and "acceptance". Te English word "orthodoxy" derives from doxa. Jonathan Leicester suggests that belief has the purpose of guiding action rather than indicating truth. Tought, Word and Deed interlock with truth statements that build belief; what you may think you may say and thus may act oﬀ, actions in reality and they’re paradigm’s.

33 In epistemology, philosophers use the term "belief" to refer to personal attitudes associated with true or false ideas and concepts. However, "belief" does not require active introspection and circumspection. For example, we never ponder whether or not the sun will rise. We simply assume the sun will rise. Since "belief" is an important aspect of mundane life, according to Eric Schwitzgebel in the Stanford Encyclopedia of Philosophy, a related question asks: "how a physical organism can have beliefs?”

Epistemology is concerned with delineating the boundary between justifed belief and opinion, and involved generally with a theoretical philosophical study of knowledge. Te primary problem in epistemology is to understand exactly what is needed in order for us to have knowledge. In a notion derived from Plato's dialogue Teaetetus, where the epistemology of Socrates (Platon) most clearly departs from that of the sophists, who at the time of Plato seem to have defned knowledge as what is here expressed as "justifed true belief". Te tendency to translate from belief (here: doxa - common opinion) to knowledge (here: episteme), which Plato (e.g. Socrates of the dialogue) utterly dismisses, results from failing to distinguish a dispositive belief (gr. 'doxa', not 'pistis') from knowledge (episteme) when the opinion is regarded true (here: orthé), in terms of right, and juristically so (according to the premises of the dialogue), which was the task of the rhetors to prove. Plato dismisses this possibility of an aﬃrmative relation between belief (i.e. opinion) and knowledge even when the one who opine grounds his belief on the rule, and is able to add justifcation (gr. logos: reasonable and necessarily plausible assertions/evidence/ guidance) to it. It is important to keep in mind that the sort of belief in the context of Teaetetus is not derived from the theological concept of belief, which is pistis, but doxa, which in theological terms refers to acceptance in the form of praise and glory.

Strangely, or not, Plato has been credited for the "justifed true belief" theory of knowledge, even though Plato in the Teaetetus (dialogue) elegantly dismisses it, and even posits this argument of Socrates as a cause for his death penalty. Among American epistemologists, Gettier (1963) and Goldman (1967), have questioned the "justifed true belief" defnition, and challenged the "sophists" of their time.

As a psychological phenomenon. Mainstream psychology and related disciplines have traditionally treated belief as if it were the simplest form of mental representation and therefore one of the building blocks of conscious thought; animism and its representative forms and its logics too language and expression. Philosophers have tended to be more abstract in their analysis, and much of the work examining the viability of the belief concept stems from philosophical analysis.

Te concept of belief presumes a subject (the believer) and an object of belief (the proposition). So, like other propositional attitudes, belief implies the existence of mental states and intentionality, both of which are hotly debated topics in the philosophy of mind, whose foundations and relation to brain states are still controversial.

Beliefs are sometimes divided into core beliefs (that are actively thought about) and dispositional beliefs (that may be ascribed to someone who has not thought about the issue). For example, if asked "do you believe tigers wear pink pajamas?" a person might answer that they do not, despite the fact they may never have thought about this situation before. Diﬀerent parts of the brain refect have diﬀerent belief systems, the pineal gland is for interpretation the Pureendulum, the lowest part of the brain is for understanding where as the Corenanaderlum is for Perception of these thoughts.

Tis has important implications for understanding the neuropsychology and neuroscience of belief. If the concept of belief is incoherent, then any attempt to fnd the underlying neural processes that support it will fail.

Philosopher Lynne Rudder Baker has outlined four main contemporary approaches to belief in her controversial book Saving Belief:

Our common-sense understanding of belief is correct - Sometimes called the "mental sentence theory," in this conception, beliefs exist as coherent entities, and the way we talk about them in everyday life is a valid basis for scientifc endeavour. Jerry Fodor is one of the principal defenders of this point of view.

Our common-sense understanding of belief may not be entirely correct, but it is close enough to make some useful predictions - Tis view argues that we will eventually reject the idea of belief as we know it now, but that there may be a correlation between what we take to be a belief when someone says "I believe that snow is white" and how a future theory of psychology will explain this behaviour. Most notably, philosopher Stephen Stich has argued for this particular understanding of belief.

Our common-sense understanding of belief is entirely wrong and will be completely superseded by a radically diﬀerent theory that will have no use for the concept of belief as we know it - Known as eliminativism, this view (most notably proposed by Paul and Patricia Churchland) argues that the concept of belief is like obsolete theories of times past such as the four humours theory of medicine, or the phlogiston theory of combustion. In these cases science hasn't provided us with a

34 more detailed account of these theories, but completely rejected them as valid scientifc concepts to be replaced by entirely diﬀerent accounts. Te Churchlands argue that our common-sense concept of belief is similar in that as we discover more about neuroscience and the brain, the inevitable conclusion will be to reject the belief hypothesis in its entirety.

Our common-sense understanding of belief is entirely wrong; however, treating people, animals, and even computers as if they had beliefs is often a successful strategy - Te major proponents of this view, Daniel Dennett and Lynne Rudder Baker, are both eliminativists in that they hold that beliefs are not a scientifcally valid concept, but they don't go as far as rejecting the concept of belief as a predictive device. Dennett gives the example of playing a computer at chess. While few people would agree that the computer held beliefs, treating the computer as if it did (e.g. that the computer believes that taking the opposition's queen will give it a considerable advantage) is likely to be a successful and predictive strategy. In this understanding of belief, named by Dennett the intentional stance, belief-based explanations of mind and behaviour are at a diﬀerent level of explanation and are not reducible to those based on fundamental neuroscience, although both may be explanatory at their own level.

Strategic approaches make a distinction between rules, norms and beliefs as follows: Rules. Explicit regulative processes such as policies, laws, inspection routines, or incentives. Rules function as a coercive regulator of behavior and are dependent upon the imposing entity’s ability to enforce them. Norms. Regulative mechanisms accepted by the social collective. Norms are enforced by normative mechanisms within the organization and are not strictly dependent upon law or regulation. Beliefs. Te collective perception of fundamental truths governing behavior. Te adherence to accepted and shared beliefs by members of a social system will likely persist and be diﬃcult to change over time. Strong beliefs about determinant factors (i.e., security, survival, or honor) are likely to cause a social entity or group to accept rules and norms.

Epistemological belief compared to religious belief, Historically belief-in belonged in the realm of religious thought, belief- that instead belonged to epistemological considerations. Belief-in To "believe in" someone or something is a distinct concept from "believing-that." Tere are at least these types of belief- in:

Commendatory / Faith - we may make an expression of 'faith' in respect of some performance by an agent X, when without prejudice to the truth value of the factual outcome or even confdence in X otherwise, we expect that specifc performance. In particular self-confdence or faith in one's self is this kind of belief.

Existential claim - to claim belief in the existence of an entity or phenomenon in a general way with the implied need to justify its claim to existence. It is often used when the entity is not real, or its existence is in doubt. "He believes in witches and ghosts" or "many people believe in Santa Claus" or "I believe in a deity" are typical examples. Te linguistic form is distinct from the assertion of the truth of a proposition since verifcation is either considered impossible/irrelevant or a counterfactual situation is assumed. Belief-that Economical belief Economic beliefs are beliefs which are reasonably and necessarily contrary to the tenet of rational choice or instrumental rationality. Studies of the Austrian tradition of the economic thought, in the context of analysis of the infuence and subsequent degree of change resulting from existing economic knowledge and belief, has contributed the most to the subsequent holistic collective analysis.

Delusion, Insofar as the truth of belief is expressed in sentential and propositional form we are using the sense of belief-that rather than belief-in. Delusion arises when the truth value of the form is clearly nil or negative.

Delusions are defned as beliefs in psychiatric diagnostic criteria (for example in the Diagnostic and Statistical Manual of Mental Disorders). Psychiatrist and historian G.E. Berrios has challenged the view that delusions are genuine beliefs and instead labels them as "empty speech acts," where aﬀected persons are motivated to express false or bizarre belief statements due to an underlying psychological disturbance. However, the majority of mental health professionals and researchers treat delusions as if they were genuine beliefs.

In Lewis Carroll's Trough the Looking-Glass the White Queen says, "Why, sometimes I've believed as many as six impossible things before breakfast." Tis is often quoted in mockery of the common ability of people to entertain beliefs contrary to fact. Tus are we prisoners of description or masters of meaning.

Formation. We are infuenced by many factors that ripple through our minds as our beliefs form, evolve, and may eventually change Psychologists study belief formation and the relationship between beliefs and actions. Tree models of belief formation and change have been proposed:

Te conditional inference process, When people are asked to estimate the likelihood that a statement is true, they search their memory for information that has implications for the validity of this statement. Once this information has been identifed, they estimate the likelihood that the statement would be true if the information were true, and the likelihood that the statement would be true if the information were false. If their estimates for these two probabilities diﬀer, people average

35 them, weighting each by the likelihood that the information is true and false (respectively). Tus, information bears directly on beliefs of another, related statement.

Linear models of belief formation; unlike the previous model, this one takes into consideration the possibility of multiple factors infuencing belief formation. Using regression procedures, this model predicts belief formation on the basis of several diﬀerent pieces of information, with weights assigned to each piece on the basis of their relative importance.

Information processing models of belief formation and change, existent from universal claims of primordial modes of truths. Tese models address the fact that the responses people have to belief-relevant information is unlikely to be predicted from the objective basis of the information that they can recall at the time their beliefs are reported. Instead, these responses refect the number and meaning of the thoughts that people have about the message at the time that they encounter it.

Some infuences on people's belief formation include: Internalization of beliefs during childhood, which can form and shape our beliefs in diﬀerent domains. Albert Einstein is often quoted as having said that "Common sense is the collection of prejudices acquired by age eighteen." Political beliefs depend most strongly on the political beliefs most common in the community where we live. Most individuals believe the religion they were taught in childhood.

Charismatic leaders can form and/or modify beliefs (even if those beliefs fy in the face of all previous beliefs). Is belief voluntary? Rational individuals need to reconcile their direct reality with any said belief; therefore, if belief is not present or possible, it refects the fact that contradictions were necessarily overcome using cognitive dissonance.

Advertising can form or change beliefs through repetition, shock, and association with images of sex, love, beauty, and other strong positive emotions. Contrary to intuition, a delay, known as the sleeper eﬀect, instead of immediate succession may increase an advertisement's ability to persuade viewer's beliefs if a discounting cue is present.

Physical trauma, especially to the head, can radically alter a person's beliefs.

However, even educated people, well aware of the process by which beliefs form, still strongly cling to their beliefs, and act on those beliefs even against their own self-interest. In Anna Rowley's book, Leadership Terapy, she states "You want your beliefs to change. It's proof that you are keeping your eyes open, living fully, and welcoming everything that the world and people around you can teach you." Tis means that peoples' beliefs should evolve as they gain new experiences.

Justifed true belief is a defnition of knowledge that gained approval during the Enlightenment, 'justifed' standing in contrast to 'revealed'. Tere have been attempts to trace it back to Plato and his dialogues. Te concept of justifed true belief states that in order to know that a given proposition is true, one must not only believe the relevant true proposition, but also have justifcation for doing so. In more formal terms, an agent S knows that a proposition P is true if and only if:

Tis theory of knowledge suﬀered a signifcant setback with the discovery of Gettier problems, situations in which the above conditions were seemingly met but that many philosophers disagree that anything is known. Robert Nozick suggested a clarifcation of "justifcation" which he believed eliminates the problem: the justifcation has to be such that were the justifcation false, the knowledge would be false. Bernecker and Dretske (2000) argue that "no epistemologist since Gettier has seriously and successfully defended the traditional view.". On the other hand, Paul Boghossian argues that the Justifed True Belief account is the "standard, widely accepted" defnition of knowledge

An extensive amount of scientifc research and philosophical discussion exists around the modifcation of beliefs, which is commonly referred to as belief revision. Generally speaking, the process of belief revision entails the believer weighing the set of truths and/or evidence, and the dominance of a set of truths or evidence on an alternative to a held belief can lead to revision. One process of belief revision is Bayesian updating and is often referenced for its mathematical basis and conceptual simplicity. However, such a process may not be representative for individuals whose beliefs are not easily characterized as probabilistic.

Tere are several techniques for individuals or groups to change the beliefs of others; these methods generally fall under the umbrella of persuasion. Persuasion can take on more specifc forms such as consciousness raising when considered in an activist or political context. Belief modifcation may also occur as a result of the experience of outcomes. Because goals are based, in part on beliefs, the success or failure at a particular goal may contribute to modifcation of beliefs that supported the original goal.

Whether or not belief modifcation actually occurs is dependent not only on the extent of truths or evidence for the alternative belief, but also characteristics outside the specifc truths or evidence. Tis includes, but is not limited to: the source characteristics of the message, such as credibility; social pressures; the anticipated consequences of a modifcation; or

36 the ability of the individual or group to act on the modifcation. Terefore, individuals seeking to achieve belief modifcation in themselves or others need to consider all possible forms of resistance to belief revision.

Partial: Without qualifcation, "belief" normally implies a lack of doubt, especially insofar as it is a designation of a life stance. In practical everyday use however, belief is normally partial and retractable with varying degrees of certainty. Is the belief liked.

A copious literature exists in multiple disciplines to accommodate this reality. In mathematics probability, fuzzy logic, fuzzy set theory, and other topics are largely directed to this.

Prediction: Diﬀerent psychological models have tried to predict people's beliefs and some of them try to estimate the exact probabilities of beliefs. For example, Robert Wyer developed a model of subjective probabilities. When people rate the likelihood of a certain statement (e.g., "It will rain tomorrow"), this rating can be seen as a subjective probability value. Te subjective probability model posits that these subjective probabilities follow the same rules as objective probabilities. For example, the law of total probability might be applied to predict a subjective probability value. Wyer found that this model produces relatively accurate predictions for probabilities of single events and for changes in these probabilities, but that the probabilities of several beliefs linked by "and" or "or" do not follow the model as well.

Religious belief refers to attitudes towards mythological, supernatural, or spiritual aspects of a religion. Religious belief is distinct from religious practice and from religious behaviours - with some believers not practicing religion and some practitioners not believing religion. Religious beliefs, being derived from ideas that are exclusive to religion, often relate to the existence, characteristics and worship of a deity or deities, to divine intervention in the universe and in human life, or to the deontological explanations for the values and practices centered on the teachings of a spiritual leader or of a spiritual group. In contrast to other belief systems, religious beliefs are usually codifed.

Forms of religious belief: While it is popularly conceived that religions each have identifable and exclusive sets of beliefs or creeds, surveys of religious belief have often found that the oﬃcial doctrine and descriptions of the beliefs oﬀered by religious authorities do not always agree with the privately held beliefs of those who identify as members of a particular religion. For a broad classifcation of the kinds of religious belief, see below.

Fundamentalism; First self-applied as a term to the conservative doctrine outlined by anti-modernist Protestants in the United States of America, "fundamentalism" in religious terms denotes strict adherence to an interpretation of scriptures that are generally associated with theologically conservative positions or traditional understandings of the text and are distrustful of innovative readings, new revelation, or alternate interpretations. Religious fundamentalism has been identifed in the media as being associated with fanatical or zealous political movements around the world that have used a strict adherence to a particular religious doctrine as a means to establish political identity and to enforce societal norms.

Orthodoxy; First used in the context of Early Christianity, the term "orthodoxy" relates to religious belief that closely follows the edicts, apologies, and hermeneutics of a prevailing religious authority. In the case of Early Christianity, this authority was the communion of bishops, and is often referred to by the term "Magisterium". Te term orthodox was applied almost as an epithet to a group of Jewish believers who held to pre-Enlightenment understanding of Judaism - now known as Orthodox Judaism. Te Eastern Orthodox Church of Christianity and the Catholic Church each consider themselves to be the true heir to Early Christian belief and practice. Te antonym of "orthodox" is "heterodox", and those adhering to orthodoxy often accuse the heterodox of apostasy, schism, or heresy.

Te Renaissance and later the Enlightenment in Europe exhibited varying degrees of religious tolerance and intolerance towards new and old religious ideas. Te Philosophes took particular exception to many of the more fantastical claims of religions and directly challenged religious authority and the prevailing beliefs associated with the established churches. In response to the liberalizing political and social movements, some religious groups attempted to integrate Enlightenment ideals of rationality, equality, and individual liberty into their belief systems, especially in the nineteenth and twentieth centuries. Reform Judaism and Liberal Christianity oﬀer two examples of such religious associations.

A term signifying derogation that is used by the religious and non-religious alike, "superstition" is the deprecated belief in supernatural causation. Tose who deny the existence of the supernatural generally attribute all beliefs associated with it to be superstitious, while a typical religious critique of superstition holds that it either encompasses beliefs in non-existent supernatural activity or that the supernatural activity is inappropriately feared or held in improper regard (see idolatry). Christian Churches strongly condemned occultism, animism, paganism, and other folk religions as mean forms of superstition, though such condemnation did not necessarily eliminate the beliefs among the common people and many such religious beliefs persist today.

37 Universalism: Some believe that religion cannot be separated from other aspects of life, or believe that certain cultures did not or do not separate their religious activities from other activities in the same way that some people in modern Western cultures do.

Some anthropologists report cultures in which gods are involved in every aspect of life - if a cow goes dry, a god has caused this, and must be propitiated, when the sun rises in the morning, a god has caused this, and must be thanked. Even in modern Western cultures, many people see supernatural forces behind every event, as described by Carl Sagan in his 1995 book Te Demon-Haunted World.

People with this worldview often regard the infuence of Western culture as inimical. Others with this worldview resist the infuence of science, and believe that science (or "so-called science") should be guided by religion. Still others with this worldview believe that all political decisions and laws should be guided by religion. Tis last belief is written into the constitutions of many Islamic nations, and is shared by some fundamentalist Christians.

In addition, beliefs about the supernatural or metaphysical may not presuppose a diﬀerence between any such thing as nature and non-nature, nor between science and what the most educated people believe. In the view of some historians, the pre-Socratic Athenians saw science, political tradition, culture and religion as not easily distinguishable, but as all part of the same body of knowledge and wisdom available to a community.

Approaches to the beliefs of others: Adherents of particular religions deal with the diﬀering doctrines and practices espoused by other religions in a variety of ways. All strains of thought appear in diﬀerent segments of all major world religions.

Exclusivism; People with exclusivist beliefs typically explain other religions as either in error, or as corruptions or counterfeits of the true faith. Tis approach is a fairly consistent feature among smaller new religious movements that often rely on doctrine that claims a unique revelation by the founder or leaders, and consider it a matter of faith that the religion has a monopoly on truth. All three major Abrahamic monotheistic religions have passages in their holy scriptures that attest to the primacy of the scriptural testimony, and indeed monotheism itself is often couched as an innovation characterized specifcally by its explicit rejection of earlier polytheistic faiths.

Exclusivism correlates with conservative, fundamentalist, and orthodox approaches of many religions while pluralistic and syncretist approaches either explicitly downplay or reject the exclusivist tendencies of the religion.

Inclusivism: People with inclusivist beliefs recognize some truth in all faith systems, highlighting agreements and minimizing diﬀerences. Tis attitude is sometimes associated with Interfaith dialogue or with the Christian Ecumenical movement, though in principle such attempts at pluralism are not necessarily inclusivist and many actors in such interactions (for example, the Roman Catholic Church) still hold to exclusivist dogma while participating in inter-religious organizations.

Explicitly inclusivist religions include many that are associated with the New Age movement as well as modern reinterpretations of Hinduism and Buddhism. Te Bahá'í Faith considers it doctrine that there is truth in all faith-systems.

Pluralism; People with pluralist beliefs make no distinction between faith systems, viewing each one as valid within a particular culture.

Syncretism; People with syncretistic views blend the views of a variety of diﬀerent religions or traditional beliefs into a unique fusion which suits their particular experiences and context (see eclecticism). Unitarian Universalism is an example of a syncretistic faith.

Adherence; Typical reasons for adherence to religion include the following: Some see belief in a God as necessary for moral behavior. Many people regard religious practices as serene, beautiful, and conducive to religious experiences, which in turn support religious beliefs. Organized religions promote a sense of community among their followers, and the moral and cultural common ground of these communities makes them attractive to people with the same values. Indeed, while religious beliefs and practices are usually connected, some individuals with substantially secular beliefs still participate in religious practices for cultural reasons.

Each religion asserts that it is a means by which its adherents may come into closer contact with God, Truth, and spiritual power. Tey all promise to free adherents from spiritual bondage, and to bring them into spiritual freedom. It naturally follows that a religion which frees its adherents from deception, sin, and spiritual death will have signifcant mental-health benefts. Abraham Maslow's research after World War II showed that Holocaust survivors tended to be those who held strong religious beliefs (not necessarily temple attendance, etc.), suggesting that belief helped people cope in extreme circumstances. Humanistic psychology went on to investigate how religious or spiritual identity may have correlations with 38 longer lifespan and better health. Te study found that humans may particularly need religious ideas to serve various emotional needs such as the need to feel loved, the need to belong to homogeneous groups, the need for understandable explanations and the need for a guarantee of ultimate justice. Other factors may involve sense of purpose, sense of identity, sense of contact with the divine. See also Man's Search for Meaning, by Viktor Frankl, detailing his experience with the importance of religion in surviving the Holocaust. Critics assert that the very fact that religion was the primary selector for research subjects may have introduced a bias, and that the fact that all subjects were Holocaust survivors may also have had an eﬀect. According to Larson et al. (2000), "[m]ore longitudinal research with better multidimensional measures will help further clarify the roles of these [religious] factors and whether they are benefcial or harmful."

Christianity is the religion of Christmas and its passing. Anyone could become Christ; its up too the good deeds of the year that can make you this fgure. You can dedicate 2 minutes a day too the thought of christmas day!

Apostasy, Existence of God § Arguments against belief in God, Typical reasons for rejection of religion include: Te fundamental doctrines of some religions are considered by some to be illogical, contrary to experience, or unsupported by sufficient evidence, and are rejected for those reasons. Even some believers may have difficulty accepting particular religious assertions or doctrines. Some people believe the body of evidence available to humans to be insufficient to justify certain religious beliefs. Tey may thus disagree with religious interpretations of ethics and human purpose, or with various creation myths.

Some religions include beliefs that certain groups of people are inferior or sinful and deserve contempt, persecution, or even death, and that non-believers will be punished for their unbelief in an after-life. Adherents to a religion may feel antipathy to unbelievers.Tere are countless examples of people of one religion or sect using religion as an excuse to murder people with diﬀerent religious beliefs. To mention just a few, there was the slaughter of the Huguenots by French Catholics in the sixteenth century; Hindus and Muslims killing each other when Pakistan separated from India in 1947; the persecution and killing of Shiite Muslims by Sunni Muslims in Iraq and the murder of Protestants by Catholics and vice versa in Ireland, (both of these examples in the late twentieth century); and the Israeli–Palestinian confict that continued. According to some critics of religion, these beliefs can encourage completely unnecessary conficts and in some cases even wars. Many atheists believe that, because of this, religion is incompatible with world peace, freedom, civil rights, equality, and good government. On the other hand, most religions perceive atheism as a threat and will vigorously and violently defend themselves against religious sterilization, making the attempt to remove public religious practices a source of strife.

Some people may be unable to accept the values that a specifc religion promotes and will therefore not join that religion. Tey may also be unable to accept the proposition that those who do not believe will go to hell or be damned, especially if said nonbelievers are close to the person.

Te maintenance of life and the achievement of self-esteem require of a person the fullest exercise of reason—but morality, people are taught, rests on and requires faith.

Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to assent to any of them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty, distrust or lack of conviction on certain facts, actions, motives, or decisions. Doubt can result in delaying or rejecting relevant action out of concern for mistakes or missed opportunities.

Divinity: In religion, divinity or godhead is the state of things that are believed to come from a supernatural power or deity, such as a god, supreme being, creator deity, or spirits, and are therefore regarded as sacred and holy. Such things are regarded as divine due to their transcendental origins or because their attributes or qualities are superior or supreme relative to things of the Earth. Divine things are regarded as eternal and based in truth, while material things are regarded as ephemeral and based in illusion. Such things that may qualify as divine are apparitions, visions, prophecies, miracles, and in some views also the soul, or more general things like resurrection, immortality, grace, and salvation. Otherwise what is or is not divine may be loosely defned, as it is used by diﬀerent belief systems. Psient believes that the gases of earths atmosphere are divine - perfect for breathing -breathe, thus pollution is seen as the main ‘evil’, and so enviromnetalism is seen as a healthiest mindset.

Te root of the word "divine" is literally "godly" (from the Latin deus, cf. Dyaus, closely related to Greek zeus, div in Persian and deva in Sanskrit), but the use varies signifcantly depending on which deity is being discussed. Tis article outlines the major distinctions in the conventional use of the terms.

Divination (from Latin divinare "to foresee, to be inspired by a god", related to divinus, divine) is the attempt to gain insight into a question or situation by way of an occultic, standardized process or ritual. Used in various forms throughout history,

39 diviners ascertain their interpretations of how a querent should proceed by reading signs, events, or omens, or through alleged contact with a supernatural agency.

Divination can be seen as a systematic method with which to organize what appear to be disjointed, random facets of existence such that they provide insight into a problem at hand. If a distinction is to be made between divination and fortune-telling, divination has a more formal or ritualistic element and often contains a more social character, usually in a religious context, as seen in traditional African medicine. Fortune-telling, on the other hand, is a more everyday practice for personal purposes. Particular divination methods vary by culture and religion.

In theology, divine light (also called divine radiance or divine refulgence) is an aspect of divine presence, specifcally an unknown and mysterious ability of God, angels, or human beings to express themselves communicatively through spiritual means, rather than through physical capacities. Divine presence, presence of God, Inner God, or simply presence is a concept in religion, spirituality, and theology that deals with the ability of a god or gods to be "present" with human beings. According to some types of monotheism God is omnipresent.

Religious texts (also known as scripture, or scriptures, from the Latin scriptura, meaning "writing") are texts which religious traditions consider to be central to their practice or beliefs. Religious texts may be used to provide meaning and purpose, evoke a deeper connection with the divine, convey religious truths, promote religious experience, foster communal identity, and guide individual and communal religious practice. Religious texts often communicate the practices or values of a religious traditions and can be looked to as a set of guiding principles which dictate physical, mental, spiritual, or historical elements considered important to a specifc religion. Te terms 'sacred' text and 'religious' text are not necessarily interchangeable in that some religious texts are believed to be sacred because of their nature as divinely or supernaturally revealed or inspired, whereas some religious texts are simply narratives pertaining to the general themes, practices, or important fgures of the specifc religion, and not necessarily considered sacred by itself. A core function of a religious text making it sacred is its ceremonial and liturgical role, particularly in relation to sacred time, the liturgical year, the divine eﬃcacy and subsequent holy service; in a more general sense, its performance.

It is not possible to create an exhaustive list of religious texts, because there is no single defnition of which texts are recognized as religious.

Faith: complete trust or confdence in someone or something. James W. Fowler (1940–2015) proposes a series of stages of faith-development (or spiritual development) across the human life-span. His stages relate closely to the work of Piaget, Erikson, and Kohlberg regarding aspects of psychological development in children and adults. Fowler defnes faith as an activity of trusting, committing, and relating to the world based on a set of assumptions of how one is related to others and the world.

Stages of faith: Intuitive-Projective: a stage of confusion and of high impressionability through stories and rituals (pre-school period). Mythic-Literal: a stage where provided information is accepted in order to conform with social norms (school-going period). Synthetic-Conventional: in this stage the faith acquired is concreted in the belief system with the forgoing of personifcation and replacement with authority in individuals or groups that represent one's beliefs (early-late adolescence). Individuative-Refective: in this stage the individual critically analyzes adopted and accepted faith with existing systems of faith. Disillusion or strengthening of faith happens in this stage. Based on needs, experiences and paradoxes (early adulthood). Conjunctive faith: in this stage people realize the limits of logic and, facing the paradoxes or transcendence of life, accept the "mystery of life" and often return to the sacred stories and symbols of the pre-acquired or re-adopted faith system. Tis stage is called negotiated settling in life (mid-life). Universalizing faith: this is the "enlightenment" stage where the individual comes out of all the existing systems of faith and lives life with universal principles of compassion and love and in service to others for upliftment, without worries and doubt (middle-late adulthood (45–65 years old and plus). No hard-and-fast rule requires individuals pursuing faith to go through all six stages. Tere is a high probability for individuals to be content and fxed in a particular stage for a lifetime; stages from 2-5 are such stages. Stage 6 is the summit of faith development. Tis state is often considered as "not fully" attainable.

Superstition is a pejorative term for any belief or practice that is irrational - i.e., it arises from ignorance, a misunderstanding of science or causality, a positive belief in fate or magic, or fear of that which is unknown. "Superstition" also refers to religious beliefs or actions arising from irrationality. Te superstitious practice of placing a rusty nail in a lemon is believed to ward oﬀ the evil eye and evil in general, as detailed in the folklore text Popular Beliefs and Superstitions from Utah. Te word superstition is often used to refer to a religion not practiced by the majority of a given society regardless of whether the prevailing religion contains superstitions. It is also commonly applied to beliefs and practices surrounding luck, prophecy, and certain spiritual beings, particularly the belief that future events can be foretold by specifc (apparently) unrelated prior events.

40 Luck is the experience of notably positive, negative, or improbable events. Te naturalistic interpretation is that positive and negative events happen all the time in human lives, both due to random and non-random natural and artifcial processes, and that even improbable events can happen by random chance. In this view, being "lucky" or "unlucky" is simply a descriptive label that points out an event's positivity, negativity, or improbability. Supernatural interpretations of luck consider it to be an attribute of a person or object, or the result of a favorable or unfavorable view of a deity upon a person. Tese interpretations often prescribe how luckiness or unluckiness can be obtained, such as by carrying a lucky charm or making sacrifces or prayers to a deity. Saying someone is "born lucky" then might mean, depending on the interpretation, anything from that they have been born into a good family or circumstance, or that they habitually experience improbably positive events due to some inherent property or the lifelong favor of a god or goddess in a monotheistic or polytheistic religion.

Many superstitions are related to luck, though these are often specifc to a given culture or set of related cultures, and sometimes contradictory. For example, lucky symbols include the number 7 in Christian-infuenced cultures, but the number 8 in Chinese-infuenced cultures. Unlucky symbols and events include entering and leaving a house by diﬀerent doors in Greek culture, throwing rocks in to the wind in Navajo culture, and ravens in Western culture. Some of these associations may derive from related facts or desires. For example, in Western culture opening an umbrella indoors might be considered unlucky partly because it could poke someone in the eye, whereas shaking hands with a chimney sweep might be considered lucky partly because it is a kind but unpleasant thing to do given the dirty nature of their work. In Chinese culture, the association of the number 4 as a homophone with the word for death may explain why it is considered unlucky. Extremely complicated and sometimes contradictory systems for prescribing auspicious and inauspicious times and arrangements of things have been devised, for example feng shui in Chinese culture and systems of astrology in various cultures around the world.

Many polytheistic religions have specifc gods or goddesses that are associated with luck, including Fortuna and Felicitas in the Ancient Roman religion (the former related to the words "fortunate" and "unfortunate" in English), Dedun in Nubian religion, the Seven Lucky Gods in Japanese mythology, mythical American serviceman John Frum in Polynesian cargo cults, and the inauspicious Alakshmi in Hinduism.

Animism (from Latin anima, "breath, spirit, life") is the religious belief that objects, places and creatures all possess a distinct spiritual essence. Potentially, animism perceives all things—animals, plants, rocks, rivers, weather systems, human handiwork and perhaps even words—as animated and alive.

Animism is used in the anthropology of religion as a term for the belief system of many indigenous peoples, especially in contrast to the relatively more recent development of organised religions. Although each culture has its own diﬀerent mythologies and rituals, "animism" is said to describe the most common, foundational thread of indigenous peoples' "spiritual" or "supernatural" perspectives. Te animistic perspective is so widely held and inherent to most indigenous peoples that they often do not even have a word in their languages that corresponds to "animism" (or even “religion"); the term is an anthropological construct.

Largely due to such ethnolinguistic and cultural discrepancies, opinion has diﬀered on whether animism refers to an ancestral mode of experience common to indigenous peoples around the world, or to a full-fedged religion in its own right. Te currently accepted defnition of animism was only developed in the late 19th century by Sir Edward Tylor, who created it as "one of anthropology's earliest concepts, if not the frst".

Animism encompasses the beliefs that all material phenomena have agency, that there exists no hard and fast distinction between the spiritual and physical (or material) world and that soul or spirit or sentience exists not only in humans, but also in other animals, plants, rocks, geographic features such as mountains or rivers or other entities of the natural environment, including thunder, wind and shadows. Animism may further attribute souls to abstract concepts such as words, true names or metaphors in mythology.

Shamanism is a practice that involves a practitioner reaching altered states of consciousness in order to perceive and interact with a spirit world and channel these transcendental energies into this world.

A shaman (/ˈʃɑːmən/ SHAH-men or /ˈʃeɪmən/ SHAY-mən) is someone who is regarded as having access to, and infuence in, the world of benevolent and malevolent spirits, who typically enters into a trance state during a ritual, and practices divination and healing. Te word "shaman" probably originates from the Tungusic Evenki language of North Asia. According to ethnolinguist Juha Janhunen, "the word is attested in all of the Tungusic idioms" such as Negidal, Lamut, Udehe/Orochi, Nanai, Ilcha, Orok, Manchu and Ulcha, and "nothing seems to contradict the assumption that the meaning 'shaman' also derives from Proto- Tungusic" and may have roots that extend back in time at least two millennia. Te term was introduced to the west after Russian forces conquered the shamanistic Khanate of Kazan in 1552. 41 Te term "shamanism" was frst applied by Western anthropologists as outside observers of the ancient religion of the Turks and Mongols, as well as those of the neighbouring Tungusic and Samoyedic-speaking peoples. Upon observing more religious traditions across the world, some Western anthropologists began to also use the term in a very broad sense, to describe unrelated magico-religious practices found within the ethnic religions of other parts of Asia, Africa, Australasia and even completely unrelated parts of the Americas, as they believed these practices to be similar to one another.

Mircea Eliade writes, "A frst defnition of this complex phenomenon, and perhaps the least hazardous, will be: shamanism = 'technique of religious ecstasy’." Shamanism encompasses the premise that shamans are intermediaries or messengers between the human world and the spirit worlds. Shamans are said to treat ailments/illness by mending the soul. Alleviating traumas affecting the soul/spirit restores the physical body of the individual to balance and wholeness. Te shaman also enters supernatural realms or dimensions to obtain solutions to problems afflicting the community. Shamans may visit other worlds/dimensions to bring guidance to misguided souls and to ameliorate illnesses of the human soul caused by foreign elements. Te shaman operates primarily within the spiritual world, which in turn affects the human world. Te restoration of balance results in the elimination of the ailment.

Beliefs and practices that have been categorised this way as "shamanic" have attracted the interest of scholars from a wide variety of disciplines, including anthropologists, archaeologists, historians, religious studies scholars, philosophers and psychologists. Hundreds of books and academic papers on the subject have been produced, with a peer-reviewed academic journal being devoted to the study of shamanism. In the 20th century, many Westerners involved in the countercultural movement have created modern magico-religious practices infuenced by their ideas of indigenous religions from across the world, creating what has been termed neoshamanism or the neoshamanic movement. It has aﬀected the development of many neopagan practices, as well as faced a backlash and accusations of cultural appropriation, exploitation and misrepresentation when outside observers have tried to represent cultures they do not belong to.

Akashic: In theosophy and anthroposophy, the Akashic records are a compendium of all human events, thoughts, words, emotions, and intent ever to have occurred in the past, present, or future. Tey are believed by theosophists to be encoded in a non-physical plane of existence known as the etheric plane. Tere are anecdotal accounts but no scientifc evidence for existence of the Akashic records. Akasha (ākāśa आकाश) is the Sanskrit word for 'aether' or 'atmosphere'. Also, in Hindi, akash (आकाश) means 'sky' or ‘heaven'.

Agnosticism is the view that the existence of God, of the divine or the supernatural is unknown or unknowable.

According to the philosopher William L. Rowe, "agnosticism is the view that human reason is incapable of providing suﬃcient rational grounds to justify either the belief that God exists or the belief that God does not exist". Agnosticism is the doctrine or tenet of agnostics with regard to the existence of anything beyond and behind material phenomena or to knowledge of a First Cause or God, and is not a religion.

British biologist Tomas Henry Huxley coined the word "agnostic" in 1869. Earlier thinkers, however, had written works that promoted agnostic points of view, such as Sanjaya Belatthaputta, a 5th-century BCE Indian philosopher who expressed agnosticism about any afterlife and Protagoras, a 5th-century BCE Greek philosopher who expressed agnosticism about the existence of "the gods". Te Nasadiya Sukta in the Rigveda is agnostic about the origin of the universe.

Irreligion (adjective form: non-religious or irreligious) is the absence, indiﬀerence, rejection of, or hostility towards religion.

Irreligion may include some forms of theism, depending on the religious context it is defned against; for example, in 18th- century Europe, the epitome of irreligion was deism, while in contemporary East Asia the shared term meaning "irreligion" or "no religion" (無宗教, Chinese pron. wú zōngjiào, Japanese pron. mu shūkyō), with which the majority of East Asian populations identify themselves, implies non-membership in one of the institutional religions (such as Buddhism and Christianity), and not necessarily non-belief in traditional folk religions collectively represented by Chinese Shendao and Japanese Shinto (both meaning "ways of gods").

Nontheism or non-theism is a range of both religious and nonreligious attitudes characterized by the absence of espoused belief in a God or gods. Nontheism has generally been used to describe apathy or silence towards the subject of God and diﬀers from an antithetical, explicit atheism. Nontheism does not necessarily describe atheism or disbelief in God; it has been used as an umbrella term for summarizing various distinct and even mutually exclusive positions, such as agnosticism, ignosticism, ietsism, skepticism, pantheism, atheism, strong or positive atheism, implicit atheism, and apatheism. It is in use in the felds of Christian apologetics and general liberal theology.

42 Within the scope of nontheistic agnosticism, Philosopher Anthony Kenny distinguishes between agnostics who fnd the claim "God exists" uncertain and theological noncognitivists who consider all discussion of God to be meaningless. Some agnostics, however, are not nontheists but rather agnostic theists.

Other related philosophical opinions about the existence of deities are ignosticism and skepticism. Because of the various defnitions of the term God, a person could be an atheist in terms of certain conceptions of gods, while remaining agnostic in terms of others.

Atheism is, in the broadest sense, the absence of belief in the existence of deities. Less broadly, atheism is the rejection of belief that any deities exist. In an even narrower sense, atheism is specifcally the position that there are no deities or no voice when speaking to a god. Atheism is contrasted with theism, which, in its most general form, is the belief that at least one deity exists. Atheism a parallel in Psient is all the religions viewed as a truth just not as one single theology, yet psient.

Te etymological root for the word atheism originated before the 5th century BCE from the ancient Greek ἄθεος (atheos), meaning "without god(s)". In antiquity it had multiple uses as a pejorative term applied to those thought to reject the gods worshiped by the larger society, those who were forsaken by the gods or those who had no commitment to belief in the gods. Te term denoted a social category created by orthodox religionists into which those who did not share their religious beliefs were placed. Te actual term atheism emerged frst in the 16th century. With the spread of freethought, skeptical inquiry, and subsequent increase in criticism of religion, application of the term narrowed in scope. Te frst individuals to identify themselves using the word atheist lived in the 18th century during the Age of Enlightenment. Te French Revolution, noted for its "unprecedented atheism," witnessed the frst major political movement in history to advocate for the supremacy of human reason. Te French Revolution can be described as the frst period where atheism became implemented politically.

Arguments for atheism range from the philosophical to social and historical approaches. Rationales for not believing in deities include arguments that there is a lack of empirical evidence, the problem of evil, the argument from inconsistent revelations, the rejection of concepts that cannot be falsifed, and the argument from nonbelief. Although some atheists have adopted secular philosophies (e.g. secular humanism), there is no one ideology or set of behaviors to which all atheists adhere. Atheism is a more parsimonious position than theism and is the position in which everyone is born; therefore it has been argued that the burden of proof lies not on the atheist to disprove the existence of God but on the theist to provide a rationale for theism. However, others have disagreed with the view of being born into such a position.

Te word oracle comes from the Latin verb ōrāre "to speak" and properly refers to the priest or priestess uttering the prediction. In extended use, oracle may also refer to the site of the oracle, and to the oracular utterances themselves, called khrēsmoi (χρησμοί) in Greek.

Oracles were thought to be portals through which the gods spoke directly to people. In this sense they were diﬀerent from seers (manteis, μάντεις) who interpreted signs sent by the gods through bird signs, animal entrails, and other various methods.

Te most important oracles of Greek antiquity were Pythia, priestess to Apollo at Delphi, and the oracle of Dione and Zeus at Dodona in Epirus. Other temples of Apollo were located at Didyma on the coast of Asia Minor, at Corinth and Bassae in the Peloponnese, and at the islands of Delos and Aegina in the Aegean Sea.

Te Sibylline Oracles are a collection of oracular utterances written in Greek hexameters ascribed to the Sibyls, ‘oraclers’ who uttered divine revelations in frenzied states.

In religion, a prophet is an individual who has been contacted by a divine being in order to speak on the entity's behalf, serving as an intermediary with humanity by delivering messages or teachings from the supernatural source to other people. Te message that the prophet conveys is called a prophecy, which transports— at least in Judaism—a message beyond mere pagan soothsaying, augury, divination, or forecasting, and, most prominently in the neviim of the Tanakh, often comprises issues of social justice.

Claims of prophethood have existed in many cultures through history, including Judaism, Christianity, Islam, in Ancient Greek Philosophy, Zoroastrianism, Manichaeism, and many others. Prophets are traditionally regarded as having a role in society that promotes change due to their messages and actions which often convey God's displeasure concerning the behavior of the people.

A saint (also historically known as a hallow) is a person who is recognized as having an exceptional degree of holiness or likeness or closeness to God. Depending on the context and denomination, the term also retains its original Christian meaning, as any believer who is "in Christ" and in whom Christ dwells, whether in Heaven or on Earth. In Anglican, 43 Roman Catholic, Eastern Orthodox, Lutheran, and Oriental Orthodox doctrine, all of their faithful deceased in Heaven are considered to be saints, but some are considered worthy of greater honor or emulation; oﬃcial ecclesiastical recognition, and consequently veneration, is given to some saints through the process of canonization in the Catholic Church or glorifcation in the Eastern Orthodox Church. Each religion has its saints.

A priest or priestess (feminine) (/priːst/ from Greek πρεσβύτερος presbýteros through Latin presbyter, "elder", or from Old High German priast, prest, from Vulgar Latin "provost" "one put over others", from Latin praepositus "person placed in charge"), is a religious leader authorized to perform the sacred rituals of a religion, especially as a mediatory agent between humans and one or more deities. Tey also have the authority or power to administer religious rites; in particular, rites of sacrifce to, and propitiation of, a deity or deities. Teir oﬃce or position is the priesthood, a term which also may apply to such persons collectively.

A monk (/mʌŋk/, from Greek: μοναχός, monachos, "single, solitary" and Latin monachus) is a person who practices religious asceticism by monastic living, either alone or with any number of other monks. A monk may be a person who decides to dedicate his life to serving all other living beings, or to be an ascetic who voluntarily chooses to leave mainstream society and live his or her life in prayer and contemplation. Te concept is ancient and can be seen in many religions and in philosophy.

In the Greek language the term can apply to women, but in modern English it is mainly in use for men. Te word nun is typically used for female monastics.

Although the term monachos is of Christian origin, in the English language monk tends to be used loosely also for both male and female ascetics from other religious or philosophical backgrounds. However, being generic, it is not interchangeable with terms that denote particular kinds of monk, such as cenobite, hermit, anchorite, hesychast, or solitary.

A nun is a member of a religious community of women, typically one living under vows of poverty, chastity, and obedience. She may have decided to dedicate her life to serving all other living beings, or she might be an ascetic who voluntarily chose to leave mainstream society and live her life in prayer and contemplation in a monastery or convent. Te term "nun" is applicable to Catholics (eastern and western traditions), Orthodox Christians, Anglicans, Lutherans, Jains, Buddhists, Taoists, Hindus and some other religious traditions.

While in common usage the terms "nun" and "sister" are often used interchangeably (the same title of "Sister" for an individual member of both forms), they are considered diﬀerent ways of life, with a "nun" being a religious woman who lives a contemplative and cloistered life of meditation and prayer for the salvation of others, while a "religious sister", in religious institutes like St. Mother Teresa's Missionaries of Charity, lives an active vocation of both prayer and service, often to the needy, ill, poor, and uneducated.

In religion, ethics, and philosophy, "good and evil" is a very common dichotomy. In cultures with Manichaean and Abrahamic religious infuence, evil is usually perceived as the antagonistic opposite of good. Good is that which should prevail and evil should be defeated. In cultures with Buddhist spiritual infuence, this antagonistic duality itself must be overcome through achieving Śūnyatā, or emptiness. Tis is the recognition of good and evil not being unrelated, but two parts of a greater whole; unity, oneness, a Monism.

As a religious concept, basic ideas of a dichotomy between good and evil has developed so that today:

Good is a broad concept but it typically deals with an association with life, charity, continuity, happiness, love and justice. Evil is typically associated with conscious and deliberate wrongdoing, discrimination designed to harm others, humiliation of people designed to diminish their psychological needs and dignity, destructiveness, and acts of unnecessary and/or indiscriminate violence. Te dilemma of the human condition and humans' and their capacity to perform both good and evil activities.

Te nature of being good has been given many treatments; one is that the good is based on the natural love, bonding, and aﬀection that begins at the earliest stages of personal development; another is that goodness is a product of knowing truth. Diﬀering views also exist as to why evil might arise. Many religious and philosophical traditions claim that evil behavior is an aberration that results from the imperfect human condition (e.g. "Te Fall of Man"). Sometimes, evil is attributed to the existence of free will and human agency. Some argue that evil itself is ultimately based in an ignorance of truth (i.e., human value, sanctity, divinity). A variety of Enlightenment thinkers have alleged the opposite, by suggesting that evil is learned as a consequence of tyrannical social structures.

44 In religion, ethics, and philosophy, goodness and evil, or simply good and evil, is the concept of all human desires and behaviors as conforming to a dualistic spectrum—wherein in one direction are aspects that are wisely reverent of life and continuity ("good"), and in the other are aspects that are vainly reverent of death and destruction (“evil").

Friendship is a relationship of mutual aﬀection between people. Friendship is a stronger form of interpersonal bond than an association. Friendship has been studied in academic felds such as communication, sociology, social psychology, anthropology, and philosophy. Various academic theories of friendship have been proposed, including social exchange theory, equity theory, relational dialectics, and attachment styles.

Although there are many forms of friendship, some of which may vary from place to place, certain characteristics are present in many types of such bonds. Such characteristics include aﬀection; kindness, love, virtue, sympathy, empathy, honesty, altruism, loyalty, mutual understanding and compassion, enjoyment of each other's company, trust, and the ability to be oneself, express one's feelings to others , and make mistakes without fear of judgment from the friend.

An enemy or a foe is an individual or a group that is seen as forcefully adverse or threatening. Te concept of an enemy has been observed to be "basic for both individuals and communities". Te term "enemy" serves the social function of designating a particular entity as a threat, thereby invoking an intense emotional response to that entity. Te state of being or having an enemy is enmity, foehood or foeship.

While the term is applied to events and conditions without agency, the forms of evil addressed in this article presume an evildoer or doers.

Hell, in many religious and folkloric traditions, is a place or state of torment and punishment in an afterlife. Religions with a linear divine history often depict hells as eternal destinations while religions with a cyclic history often depict a hell as an intermediary period between incarnations. Typically these traditions locate hell in another dimension or under the Earth's surface and often include entrances to Hell from the land of the living. Other afterlife destinations include Heaven, Purgatory, Paradise, and Limbo.

Other traditions, which do not conceive of the afterlife as a place of punishment or reward, merely describe hell as an abode of the dead, the grave, a neutral place located under the surface of Earth (for example, see Sheol and Hades).

Te Devil (from Greek: διάβολος diábolos "slanderer, accuser") designate the personifcation of evil in various cultures. In Abrahamic religions he is often identifed with Satan. Te devil was created by god and deals with evil. Te devil was created by god to deal with evil, wy should god concern his time with those who commit wrong, this is the devils purpose. You only die if you go to hell!

Christianity identifes the Devil ("Satan") with the serpent who tempted Adam and Eve to eat the forbidden fruit, and describes him as a "fallen angel" who terrorizes the world through evil, is the antithesis of Truth, and shall be condemned, together with the fallen angels who follow him, to eternal fre at the Last Judgement.

Shaitan or Iblis is the Devil in Islam. While Iblis refers to the particular personifed Devil, Shaitan can apply to any creature, that cause mischief and oppose God.

Some non-Abrahamic religions contain fgures similar to the Devil, such as the Buddhist demon Mara and the Zoroastrian spirit Angra Mainyu.

Satan is a malevolent fgure in the Abrahamic religions who seeks to seduce humans into falsehood and sin. In Christianity and Islam, he is usually seen as a fallen angel, or a jinn, who used to possess great piety and beauty, but rebelled against God out of hubris. God allows Satan temporary power over the fallen world and grants him a host of demons.

A fgure known as "the satan" frst appears in the Tanakh as a heavenly prosecutor, a member of the sons of God subordinate to Yahweh, who prosecutes the nation of Judah in the heavenly court and tests the loyalty of Yahweh's followers by forcing them to suﬀer. During the intertestamental period, possibly due to infuence from the Zoroastrian fgure of Angra Mainyu, the satan developed into a malevolent entity with abhorrent qualities in dualistic opposition to God. In the apocryphal Book of Jubilees, Yahweh grants the satan (referred to as Mastema) authority over a group of fallen angels to tempt humans to sin and punish them.

In the Synoptic Gospels, Satan tempts Jesus in the desert and is identifed as the cause of illness and temptation. Satan is described in the New Testament as the "ruler of the demons" and "the God of this Age". In the Book of Revelation, Satan appears as a Great Red Dragon, who is defeated by Michael the Archangel and cast down from Heaven. He is later bound 45 for one thousand years, but is briefy set free before being ultimately defeated and cast into the Lake of Fire. In Christianity, Satan is also known as the Devil and, although the Book of Genesis does not mention him, he is often identifed with the serpent in the Garden of Eden.

Satan's appearance is never described in the Bible, but, since the ninth century, he has often been shown in Christian art with horns, cloven hooves, unusually hairy legs, and a tail, often naked and holding a pitchfork. Tese are an amalgam of traits derived from various pagan deities, including Pan, Poseidon, and Bes. In medieval times, Satan played minimal role in Christian theology and was used as a comic relief fgure in mystery plays. During the early modern period, Satan's signifcance greatly increased as beliefs such as demonic possession and witchcraft became more prevalent. During the Age of Enlightenment, belief in the existence of Satan became harshly criticized. Nonetheless, belief in Satan has persisted, particularly in the Americas.

In Abran, the Devil, is an entity who was created by God to deal with the sins of man . People can commit sin, by infecting their minds with ("evil suggestions”) God notices and the Devil and punishment begins. Te devil is viewed as the master of evil, some groups have very diﬀerent beliefs. During Seance, the devil is considered a deity who is either worshipped or revered for removing evil of others. Te devil does not punish unless you have yourself have punished someone else.

Evil, in a general context, is the absence or opposite of that which is described as being good. Often, evil denotes profound immorality. In certain religious contexts, evil has been described as a supernatural force. Defnitions of evil vary, as does the analysis of its motives. However, elements that are commonly associated with evil involve unbalanced behavior involving anger.

While the term is applied too events and conditions without agency, the forms of evil addressed in this article presume an evildoer or doers.

A demon (from Koine Greek δαιμόνιον daimónion) is a supernatural and often malevolent being prevalent in religion, occultism, literature, fction, mythology and folklore. In Ancient Near Eastern religions as well as in the Abrahamic traditions, including ancient and medieval Christian demonology, a demon is considered a harmful spiritual entity, below the heavenly planes which may cause demonic possession, calling for an exorcism. In Western occultism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish Aggadah and Christian demonology, a demon is believed to be a spiritual entity that may be conjured and controlled. Demons are usually conjured by people via the imagination through curses or spite; hence the word possession is used.

Religious and philosophical views tend to agree that, while "good and evil" is a concept and therefore an abstraction, goodness is intrinsic to human nature and is ultimately based on the natural love, bonding, aﬀection that people grow to feel for other people.

Likewise, most religious and philosophical interpretations agree that evil is ultimately based in an ignorance of truth (i.e. human value, sanctity, divinity), and evil behavior itself is an aberration —one that defes any understanding save that the path to evil is one of confusion and excessive desire (greed). In physics and statistical thermodynamics, the property of goodness or order is often referred to as a state of low entropy.

Te two questions are subtly diﬀerent. One may answer the frst question by researching the world by use of social science, and examining the preferences that people assert. However, one may answer the second question by use of reasoning, introspection, prescription, and generalization. Te former kind of method of analysis is called "descriptive", because it attempts to describe what people actually view as good or evil; while the latter is called "normative", because it tries to actively prohibit evils and cherish goods. Tese descriptive and normative approaches can be complementary. For example, tracking the decline of the popularity of slavery across cultures is the work of descriptive ethics, while advising that slavery be avoided is normative.

Ethics is the study of the fundamental questions concerning the nature and origins of the good and the evil, including inquiry into the nature of good and evil, as well as the meaning of evaluative language. In this respect, meta-ethics is not necessarily tied to investigations into how others see the good, or of asserting what is good within the practices of being of nature.

Pagan and paganism were pejorative terms for the same polytheistic group, implying its inferiority. Paganism has broadly connoted the "religion of the peasantry”, and for much of its history was a derogatory term. Both during and after the Middle Ages, paganism was a pejorative term that was applied to any non- Abrahamic or unfamiliar religion, and the term presumed a belief in false god(s).

46 While most pagan religions express a world view that is pantheistic, polytheistic or animistic, there are some monotheistic pagans.

Witchcraft or witchery broadly means the practice of and belief in magical skills and abilities exercised by solitary practitioners and groups. Witchcraft is a broad term that varies culturally and societally, and thus can be diﬃcult to defne with precision, therefore cross-cultural assumptions about the meaning or signifcance of the term should be applied with caution. Witchcraft often occupies a religious divinatory or medicinal role, and is often present within societies and groups whose cultural framework includes a magical world view, moreover being a witch is a professional body and uses the language of Wiccan.

A magician is any practitioner of magic and being a magician is also a profession.A variety of personal traits may be credited with giving magical power, and frequently they are associated with an unusual birth into the world -around 50 of the professions.

However, the most common method of identifying, diﬀerentiating, and establishing magical practitioners from common people is by initiation. By means of rites the magician's relationship to the supernatural and his entry into a closed professional class is established.

A psychic is a person who claims to use extrasensory perception (ESP) to identify information hidden from the normal senses, particularly involving telepathy or clairvoyance, or who performs acts that are apparently inexplicable by natural laws. Many people believe in psychic abilities, but there is no scientifc consensus as to the actual existence of such powers. Te word "psychic" is also used as an adjective to describe such abilities. In this meaning, this word has some synonyms, as parapsychic or metapsychic.

Psychics encompass people in a variety of roles. Some are theatrical performers, such as stage magicians, who use various techniques, e.g., prestidigitation, cold reading, and hot reading, to produce the appearance of such abilities for entertainment purposes. A large industry and network exists whereby people advertised as psychics provide advice and counsel to clients. Some famous psychics include Edgar Cayce, Ingo Swann, Peter Hurkos, Jose Ortiz El Samaritano, Miss Cleo, John Edward, and Sylvia Browne. Psychic powers are asserted by psychic detectives and in practices such as psychic archaeology and even psychic surgery. Psychics are frequently featured in science fction (sometimes called psionic or psyonic). Two fction series, Talent and Te Tower and Hive, encompassing eight books by Anne McCaﬀrey tell the story of telepathic, telekinetic individuals who become increasingly important to the proper function of an interstellar society. People with psychic powers appear regularly in fantasy fction, such as the novels Te Dead Zone, Carrie and Firestarter, by Stephen King, among many others.

A miracle is an event not easily explainable by natural or scientifc laws. Such an event may be attributed to a supernatural being (a deity), magic, a miracle worker, a saint or a sorcerer; conjuring magic properties.

Consecration is the solemn dedication to a special purpose or service, usually religious. Te word consecration literally means "association with the sacred". Persons, places, or things can be consecrated, and the term is used in various ways by diﬀerent groups. Te origin of the word comes from the Latin word consecrat, which means dedicated, devoted, and sacred. A synonym for to consecrate is to sanctify; a distinct antonym is to desecrate. For example you could concentrate a cannabis joint with a 12 second prayer.

Incarnation, too separate substrates from main body - too separate a substance; then use the component parts to forge a new ‘incarnation’ For example by putting together a cigarette with a wild picked nectar (variety of 9) you may forge an original incarnation. Ten consecrate.

Informally, the word "miracle" is often used to characterise any benefcial event that is statistically unlikely but not contrary to the laws of nature, such as surviving a natural disaster, or simply a "wonderful" occurrence, regardless of likelihood, such as a birth. Other such miracles might be: survival of an illness diagnosed as terminal, escaping a life-threatening situation or 'beating the odds'. Some coincidences may be seen as miracles.

A tribe is viewed, developmentally or historically, as a social group existing outside of or before the development of states. A tribe is a group of distinct people, dependent on their land for their livelihood, who are largely self-sufficient, and not integrated into the national society. It is perhaps the term most readily understood and used by the general public to describe such communities. Stephen Corry defnes tribal people as those who "have followed ways of life for many generations that are largely self-sufficient, and are clearly different from the mainstream and dominant society”. Tis defnition, however, would not apply to countries in the Middle East such as Iraq and Yemen, South Asia such as Afghanistan and many African

47 countries such as South Sudan, where the entire population is a member of one tribe or another, and tribalism itself is dominant and mainstream.

Te distinction between tribal and indigenous is important because tribal peoples have a special status acknowledged in international law. Tey often face particular issues in addition to those faced by the wider category of indigenous peoples.

Many people used the term "tribal society" to refer to societies organized largely on the basis of social, especially familial, descent groups (see clan and kinship). A customary tribe in these terms is a face-to-face community, relatively bound by kinship relations, reciprocal exchange, and strong ties to place.

"Tribe" is a contested term due to its roots of being defned by outsiders during the period of colonialism. Te word has no shared referent, whether in political form, kinship relations or shared culture. Some argue that it conveys a negative connotation of a timeless unchanging past. To avoid these implications, some have chosen to use the terms ethnic group, or nation instead.

In some places, such as India and North America, tribes are polities that have been granted legal recognition and limited autonomy by the national states.

Te term cult usually refers to a social group defned by its religious, spiritual, or philosophical beliefs, or its common interest in a particular personality, object or goal. Te term itself is controversial and it has divergent defnitions in both popular culture and academia and it also has been an ongoing source of contention among scholars across several felds of study. In the sociological classifcations of religious movements, a cult is a social group with socially deviant or novel beliefs and practices, although this is often unclear. Other researchers present a less-organized picture of cults on the basis that cults arise spontaneously around novel beliefs and practices. Groups said to be cults range in size from local groups with a few members to international organizations with millions.

Beginning in the 1930s, cults became the object of sociological study in the context of the study of religious behavior. From the 1940s the Christian countercult movement has opposed some sects and new religious movements, and it labelled them as cults for their "un-Christian" unorthodox beliefs. Te secular anti-cult movement began in the 1970s and it opposed certain groups, often charging them with mind control and partly motivated in reaction to acts of violence committed by some of their members. Some of the claims and actions of the anti-cult movements have been disputed by scholars and by the news media, leading to further public controversy.

Te term "new religious movement" refers to religions which have appeared since the mid-1800s. Many, but not all of them, have been considered to be cults. Sub-categories of cults include: Doomsday cults, political cults, destructive cults, racist cults, polygamist cults, and terrorist cults. Various national governments have reacted to cult-related issues in diﬀerent ways, and this has sometimes led to controversy.

According to the philosopher William L. Rowe, "agnosticism is the view that human reason is incapable of providing suﬃcient rational grounds to justify either the belief that God exists or the belief that God does not exist”. Agnosticism is a doctrine or set of tenets rather than a religion. It is also regarded illegal under modern law.

Apatheism (/ˌæpəˈθiːɪzəm/ a portmanteau of apathy and theism) is the attitude of apathy towards the existence or non- existence of god(s). It is more of an attitude rather than a belief, claim or belief system.

An apatheist is someone who is not interested in accepting or rejecting any claims that gods exist or do not exist. Te existence of god(s) is not rejected, but may be designated irrelevant.

Scientist and philosopher Ian von Hegner has argued that apatheism is an alternative to positions such as theism, atheism, and agnosticism, with implications that have been overlooked in modern philosophical discussions. Philosopher Trevor Hedberg has called apatheism uncharted territory in the philosophy of religion.

Deism (/ˈdiːɪzəm/ DEE-iz-əm or /ˈdeɪ.ɪzəm/ DAY-iz-əm; derived from Latin "deus" meaning "god") is a philosophical position that posits that God (or in some cases, gods) does not interfere directly with the world; conversely it can also be stated as a system of belief which posits God's existence as the cause of all things, and admits His perfection (and usually the existence of natural law and Providence) but rejects Divine revelation or direct intervention of God in the universe by miracles. It also rejects revelation as a source of religious knowledge and asserts that reason and observation of the natural world are suﬃcient to determine the existence of a single creator or absolute principle of the universe.

48 Deism gained prominence among intellectuals during the Age of Enlightenment, especially in Britain, France, Germany, and the United States. Typically, these had been raised as Christians and believed in one God, but they had become disenchanted with organized religion and orthodox teachings such as the Trinity, Biblical inerrancy, and the supernatural interpretation of events, such as miracles. Included in those infuenced by its ideas were leaders of the American and French Revolutions.

Today, deism is considered to exist in the classical and modern forms, where the classical view takes what is called a "cold" approach by asserting the non- intervention of deity in the natural behavior of the created universe, while the modern deist formulation can be either "warm" (citing an involved deity) or "cold" (citing an uninvolved deity). Tese lead to many subdivisions of modern deism, which tends, therefore, to serve as an overall category of belief.

In philosophy, naturalism is the "idea or belief that only natural (as opposed to supernatural or spiritual) laws and forces operate in the world." Adherents of naturalism (i.e., naturalists) assert that natural laws are the rules that govern the structure and behavior of the natural universe, that the changing universe at every stage is a product of these laws.

"Naturalism can intuitively be separated into an ontological and a methodological component.”,"Ontological" refers to the philosophical study of the nature of reality. Some philosophers equate naturalism with materialism. For example, philosopher Paul Kurtz argues that nature is best accounted for by reference to material principles. Tese principles include mass, energy, and other physical and chemical properties accepted by the scientifc community. Further, this sense of naturalism holds that spirits, deities, and ghosts are not real and that there is no "purpose" in nature. Such an absolute belief in naturalism is commonly referred to as metaphysical naturalism.

Assuming naturalism in working methods as the current paradigm, without the unfounded consideration of naturalism as an absolute truth with philosophical entailment, is called methodological naturalism.

With the exception of pantheists—who believe that Nature and God are one and the same thing—theists challenge the idea that nature contains all of reality. According to some theists, natural laws may be viewed as so-called secondary causes of God(s).

In the 20th century, Willard Van Orman Quine, George Santayana, and other philosophers argued that the success of naturalism in science meant that scientifc methods should also be used in philosophy. Science and philosophy are said to form a continuum, according to this view.

Monotheism has been defned as the belief in the existence of only one god that created the world, is all-powerful and intervenes in the world. A broader defnition of monotheism is the belief in one god. A distinction may be made between exclusive monotheism, and both inclusive monotheism and pluriform (panentheistic) monotheism which, while recognising various distinct gods, postulate some underlying unity.

Monotheism is distinguished from henotheism, a religious system in which the believer worships one god without denying that others may worship diﬀerent gods with equal validity, and monolatrism, the recognition of the existence of many gods but with the consistent worship of only one deity.

Te broader defnition of monotheism characterizes the traditions of Bábism, the Bahá'í Faith, Balinese Hinduism, Cao Dai (Caodaiism), Cheondoism (Cheondogyo), Christianity, Deism, Eckankar, Hindu sects such as Shaivism and Vaishnavism, Islam, Judaism, Mandaeism, Rastafari, Seicho no Ie, Sikhism, Tengrism (Tangrism), Tenrikyo (Tenriism), Yazidism, and Zoroastrianism, and elements of pre-monotheistic thought are found in early religions such as Atenism, Ancient Chinese religion, and Yahwism. Psient believes in one god and is a monotheism.

Monism is the view that attributes oneness or singleness (Greek: μόνος) to a concept (e.g., existence). Various kinds of monism can be distinguished: Priority monism states that all existing things go back to a source that is distinct from them (e.g., in Neoplatonism everything is derived from Te One). In this view only one thing is ontologically basic or prior to everything else.

Existence monism posits that, strictly speaking, there exists only a single thing (e.g., the universe), which can only be artifcially and arbitrarily divided into many things.

Substance monism ("stuff monism") asserts that a variety of existing things can be explained in terms of a single reality or substance. Substance monism posits that only one kind of stuff (e.g., matter or mind) exists, although many things may be made out of this stuff.

49 Dualism in cosmology is the moral or spiritual belief that two fundamental concepts exist, which often oppose each other. It is an umbrella term that covers a diversity of views from various religions, including both traditional religions and scriptural religions.

Moral dualism is the belief of the great complement of or confict between the benevolent and the malevolent. It simply implies that there are two moral opposites at work, independent of any interpretation of what might be "moral" and independent of how these may be represented. Moral opposites might, for example, exist in a worldview which has one god, more than one god, or none. By contrast, duo-theism, bitheism or ditheism implies (at least) two gods. While bitheism implies harmony, ditheism implies rivalry and opposition, such as between good and evil, or light and dark, or summer and winter. For example, a ditheistic system could be one in which one god is a creator, and the other a destroyer. In theology, dualism can also refer to the relationship between God and creation or God and the universe (see theistic dualism). Tis form of dualism is a belief shared in certain traditions of Christianity and Hinduism. Alternatively, in ontological dualism, the world is divided into two overarching categories. Te opposition and combination of the universe's two basic principles of yin and yang is a large part of Chinese philosophy, and is an important feature of Taoism. It is also discussed in Confucianism.

Many myths and creation motifs with dualistic cosmologies have been described in ethnographic and anthropological literature. Tese motifs conceive the world as being created, organized, or infuenced by two demiurges, culture heroes, or other mythological beings, who either compete with each other or have a complementary function in creating, arranging or infuencing the world. Tere is a huge diversity of such cosmologies. In some cases, such as among the Chukchi, the beings collaborate rather than competing, and contribute to the creation in a coequal way. In many other instances the two beings are not of the same importance or power (sometimes, one of them is even characterized as gullible). Sometimes they can be contrasted as good versus evil. Tey may be often believed to be twins or at least brothers. Dualistic motifs in mythologies can be observed in all inhabited continents. Zolotaryov concludes that they cannot be explained by diﬀusion or borrowing, but are rather of convergent origin: they are related to a dualistic organization of society (moieties); in some cultures, this social organization may have ceased to exist, but mythology preserves the memory in more and more disguised ways.

Monolatry (Greek: μόνος (monos) = single, and λατρεία (latreia) = worship) is belief in the existence of many gods but with the consistent worship of only one deity. Monolatry is distinguished from monotheism, which asserts the existence of only one god, and henotheism, a religious system in which the believer worships one god without denying that others may worship diﬀerent gods with equal validity.

Singatheism is a term coined by philologist’s to mean the worship one god at a time through many religions. It is closely related to Pluratheism, the worship of many religion’s while not rejecting the existence of one god. Te coined term in reference to the many religion and set like the Vedas, where he explained each deity is treated as supreme in turn. Yet the one mono-omni-uni is the one lord creator. is supremitist and the greatest.

Omnism is the recognition and respect of all religions; those who hold this belief are called omnists (or Omnists). Te Oxford English Dictionary (OED) quotes as the term's earliest usage by English poet Philip J. Bailey: in 1839 "I am an Omnist, and believe in all religions". In recent years, the term has been emerging anew, due to the interest of modern day self-described omnists who have rediscovered and begun to redefne the term. It can be thought of as syncretism taken to its logical extreme. However, it can also be seen as a way to accept the existence of various religions without believing in all that they profess to teach. Many omnists say that all religions contain truths, but that no one religion oﬀers all that is truth. Psient is an omnist atheology, it believes that the diﬀerent religions all have foundry in truth, all religions hold the ultimate truth’s.

In philosophy, panpsychism is the view that consciousness, mind or soul (psyche) is a universal and primordial feature of all things. Panpsychists see themselves as minds in a world of mind.

Panpsychism is one of the oldest philosophical theories, and has been ascribed to philosophers like Tales, Parmenides, Plato, Averroes, Spinoza, Leibniz and William James. Panpsychism can also be seen in ancient philosophies such as Stoicism, Taoism, Vedanta and Mahayana Buddhism. During the 19th century, panpsychism was the default theory in philosophy of mind, but it saw a decline during the middle years of the 20th century with the rise of logical positivism. Te recent interest in the hard problem of consciousness has revived interest

Panentheism (from the Ancient Greek expression πᾶν ἐν θεῷ, pān en theṓ, literally "all in God" is the belief that the divine pervades and interpenetrates every part of the universe and also extends beyond time and space. Te term was coined by the German philosopher Karl Krause in 1828 to distinguish the ideas of Georg Wilhelm Friedrich Hegel (1770–1831) and Friedrich Wilhelm Joseph Schelling (1775–1854) about the relation of God and the universe from the supposed

50 pantheism of Baruch Spinoza. Unlike pantheism, which holds that the divine and the universe are identical, panentheism maintains an ontological distinction between the divine and the non-divine and the signifcance of both.

In panentheism, God is viewed as the soul of the universe, the universal spirit present everywhere, which at the same time "transcends" all things created. While pantheism asserts that "all is God", panentheism claims that God is greater than the universe. Some versions of panentheism suggest that the universe is nothing more than the manifestation of God. In addition, some forms indicate that the universe is contained within God, like in the Kabbalah concept of tzimtzum. Also much Hindu thought – and consequently Buddhist philosophy – is highly characterized by panentheism and pantheism. Te basic tradition however, on which Krause's concept was built, seems to have been Neoplatonic philosophy and its successors in Western philosophy and Orthodox theology.

Pantheism is the belief that all reality is identical with divinity, or that everything composes an all-encompassing, immanent god. Pantheists do not believe in a distinct personal or anthropomorphic god and hold a broad range of doctrines diﬀering with regards to the forms of and relationships between divinity and reality.

Pantheism was popularized in Western culture as a theology and philosophy based on the work of the 17th-century philosopher Baruch Spinoza, particularly his book Ethics, published in 1677. Te term "pantheism" was coined by Mathematician Joseph Raphson in 1697 and has since been used to describe the beliefs of a variety of people and organizations.

Pantheistic concepts date back thousands of years, and pantheistic elements have been identifed in various religious traditions.

Polytheism (from Greek πολυθεϊσμός, polytheismos) is the worship of or belief in multiple deities, which are usually assembled into a pantheon of gods and goddesses, along with their own religions and rituals. In most religions which accept polytheism, the diﬀerent gods and goddesses are representations of forces of nature or ancestral principles, and can be viewed either as autonomous or as aspects or emanations of a creator God or transcendental absolute principle (monistic theologies), which manifests immanently in nature (panentheistic and pantheistic theologies). Most of the polytheistic deities of ancient religions, with the notable exceptions of the Ancient Egyptian and Hindu deities, were conceived as having physical bodies.

Polytheism is a type of theism. Within theism, it contrasts with monotheism, the belief in a singular God, in most cases transcendent. Polytheists do not always worship all the gods equally, but they can be henotheists, specializing in the worship of one particular deity. Other polytheists can be kathenotheists, worshiping diﬀerent deities at diﬀerent times.

Polytheism was the typical form of religion during the Bronze Age and Iron Age up to the Axial Age and the development of Abrahamic religions, the latter of which enforced strict monotheism. It is well documented in historical religions of Classical antiquity, especially ancient Greek religion and ancient Roman religion, and after the decline of Greco-Roman polytheism in tribal religions such as Germanic paganism or Slavic paganism.

Important polytheistic religions practiced today include Chinese traditional religion, Hinduism, Japanese Shinto, and various neopagan faiths.

Teism is broadly defned as the belief in the existence of the Supreme Being or deities. In popular parlance, or when contrasted with deism, the term often describes the classical conception of God that is found in Monotheism (also referred to as Classical theism) or gods found in polytheistic religions; a belief in God or in gods without the rejection of revelation as is characteristic of deism.

Creationism is the religious belief that the universe and life originated "from specifc acts of divine creation”, as opposed to the scientifc conclusion that they came about through natural processes.Te frst use of the term "creationist" to describe a proponent of creationism is found in an 1856 letter of Charles Darwin describing those who objected on religious grounds to the then emerging science of evolution. Creationism covers a spectrum of views including evolutionary creationism, a theological variant of theistic evolution which asserts that both evolutionary science and a belief in creation are true, but the term is commonly used for literal creationists who reject various aspects of science, and instead promote pseudoscientifc beliefs.

Literal creationists base their beliefs on a fundamentalist reading of religious texts, including the creation myths found in Genesis and the Quran. For young Earth creationists, these beliefs are based on a literalist interpretation of the Genesis creation narrative and rejection of the scientifc theory of evolution. Literalist creationists believe that evolution cannot adequately account for the history, diversity, and complexity of life on Earth. Pseudoscientifc branches of creationism

51 include creation science, food geology, and intelligent design, as well as subsets of pseudoarchaeology, pseudohistory, and pseudolinguistics.

Transtheism is a term coined by either philosopher Paul Tillich or Indologist Heinrich Zimmer referring to a system of thought or religious philosophy which is neither theistic, nor atheistic, but is beyond them.

Zimmer applies the term to the theological system of Jainism, which is theistic in the limited sense that the gods exist, but become irrelevant as they are transcended by moksha (that is, a system which is not non-theistic, but in which the gods are not the highest spiritual instance). Zimmer (1953, p. 182) uses the term to describe the position of the Tirthankaras having passed "beyond the godly governors of the natural order".

Te term has more recently also been applied to Buddhism, Advaita Vedanta and the Bhakti movement.

Nathan Katz in Buddhist and Western Philosophy (1981, p. 446) points out that the term "transpolytheistic" would be more accurate, since it entails that the polytheistic gods are not denied or rejected even after the development of a notion of the Absolute that transcends them, but criticizes the classifcation as characterizing the mainstream by the periphery: "like categorizing Roman Catholicism as a good example of non-Nestorianism". Te term is indeed informed by the fact that the corresponding development in the West, the development of monotheism, did not "transcend" polytheism, but abolish it, while in the mainstream of the Indian religions, the notion of "gods" (deva) was never elevated to the status of "God" or Ishwara, or the impersonal Absolute Brahman, but adopted roles comparable to Western angels. "Transtheism", according to the criticism of Katz, is then an artifact of comparative religion.

Paul Tillich uses transtheistic in Te Courage to Be (1952), as an aspect of Stoicism. Tillich stated that Stoicism and Neo- Stoicism are the way in which some of the noblest fgures in later antiquity and their followers in modern times have answered the problem of existence and conquered the anxieties of fate and death. Stoicism in this sense is a basic religious attitude, whether it appears in theistic, atheistic, or transtheistic forms.

Like Zimmer trying to express a religious notion that is neither theistic nor atheistic. However, the theism that is being transcended in Stoicism according to Tillich is not polytheism as in Jainism, but monotheism, pursuing an ideal of human courage which has emancipated itself from God.

Te courage to take meaninglessness into itself presupposes a relation to the ground of being which we have called "absolute faith." It is without a special content, yet it is not without content. Te content of absolute faith is the "god above God." Absolute faith and its consequence, the courage that takes the radical doubt, the doubt about God, into itself, transcends the theistic idea of God.

Martin Buber criticized Tillich's "transtheistic position" as a reduction of God to the impersonal "necessary being" of Tomas Aquinas.

Gnosticism (from Ancient Greek: γνωστικός gnostikos, "having knowledge", from γνῶσις gnōsis, knowledge) is a modern name for a variety of ancient religious ideas and systems, originating in Jewish milieus in the frst and second century AD. Based on their readings of the Torah and other Biblical writings, these systems believed that the material world is created by an emanation of the highest God, trapping the Divine spark within the human body. Tis Divine spark could be liberated by gnosis.

Te Gnostic ideas and systems fourished in the Mediterranean world in the second century AD, in conjunction with and infuenced by the early Christian movements and Middle Platonism. After the Second Century, a decline set in, but Gnosticism persisted throughout the centuries as an undercurrent of western culture, remanifesting with the Renaissance as Western esotericism, taking prominence with modern spirituality. In the Persian Empire, Gnosticism spread as far as China with Manicheism, while Mandaeism is still alive in Iraq.

A major question in scholarly research is the qualifcation of Gnosticism, based on the study of its texts, as either an interreligious phenomenon or as an independent religion.

Fundamentalism usually has a religious connotation that indicates unwavering attachment to a set of irreducible beliefs. However, fundamentalism has come to be applied to a tendency among certain groups—mainly, though not exclusively, in religion—that is characterized by a markedly strict literalism as it is applied to certain specifc scriptures, dogmas, or ideologies, and a strong sense of the importance of maintaining ingroup and outgroup distinctions, leading to an emphasis on purity and the desire to return to a previous ideal from which advocates believe members have strayed. Rejection of

52 diversity of opinion as applied to these established "fundamentals" and their accepted interpretation within the group is often the result of this tendency.

Depending upon the context, fundamentalism can be a pejorative rather than a neutral characterization, similar to the ways that calling political perspectives "right-wing" or "left-wing" can, for some, have negative connotations.

In a religious context, sin is the act of transgression against divine law. Sin can also be viewed as any thought or action that endangers the ideal relationship between an individual and God; or as any diversion from the perceived ideal order for human living. "To sin" has been defned from a Greek concordance as "to miss the mark".

Forgiveness is the intentional and voluntary process by which a victim undergoes a change in feelings and attitude regarding an offense, lets go of negative emotions such as vengefulness, with an increased ability to wish the offender well. Forgiveness is different from condoning (failing to see the action as wrong and in need of forgiveness), excusing (not holding the offender as responsible for the action), forgetting (removing awareness of the offense from consciousness), pardoning (granted for an acknowledged offense by a representative of society, such as a judge), and reconciliation (restoration of a relationship).

In certain contexts, forgiveness is a legal term for absolving or giving up all claims on account of debt, loan, obligation, or other claims.

As a psychological concept and virtue, the benefts of forgiveness have been explored in religious thought, the social sciences and medicine. Forgiveness may be considered simply in terms of the person who forgives including forgiving themself, in terms of the person forgiven or in terms of the relationship between the forgiver and the person forgiven. In most contexts, forgiveness is granted without any expectation of restorative justice, and without any response on the part of the offender (for example, one may forgive a person who is incommunicado or dead). In practical terms, it may be necessary for the offender to offer some form of acknowledgment, an apology, or even just ask for forgiveness, in order for the wronged person to believe themself able to forgive.

Social and political dimensions of forgiveness involves the strictly private and religious sphere of "forgiveness". Te notion of "forgiveness" is generally considered unusual in the political feld. However, Hannah Arendt considers that the "faculty of forgiveness" has its place in public aﬀairs. Te philosopher believes that forgiveness can liberate resources both individually and collectively in the face of the irreparable. During an investigation in Rwanda on the discourses and practices of forgiveness after the 1994 genocide, sociologist Benoît Guillou illustrated the extreme polysemy of the word "forgiveness" but also the eminently political character of the notion. By way of conclusion of his work, the author proposes four main fgures of forgiveness to better understanding, on the one hand, ambiguous uses and, on the other hand, the conditions under which forgiveness can mediate a resumption of social link.

Most world religions include teachings on the nature of forgiveness, and many of these teachings provide an underlying basis for many varying modern day traditions and practices of forgiveness. Some religious doctrines or philosophies place greater emphasis on the need for humans to fnd some sort of divine forgiveness for their own shortcomings, others place greater emphasis on the need for humans to practice forgiveness of one another, yet others make little or no distinction between human and divine forgiveness.

,الخلص :translit. yāšaʕ;[1] Arabic ,יָשַע :Salvation (Latin: salvatio; Ancient Greek: σωτηρία, translit. sōtēría; Hebrew translit. al-ḵalaṣ) is being saved or protected from harm or being saved or delivered from a dire situation. In religion, salvation is stated as the saving of the soul from sin and its consequences.

Te academic study of salvation is called soteriology. Soteriology (/səˌtɪəriˈɒlədʒi/; Greek: σωτηρία sōtēria "salvation" from σωτήρ sōtēr "savior, preserver" and λόγος logos "study" or "word") is the study of religious doctrines of salvation. Salvation theory occupies a place of special signifcance in many religions.

In the academic feld of religious studies, soteriology is understood by scholars as representing a key theme in a number of diﬀerent religions and is often studied in a comparative context; that is, comparing various ideas about what salvation is and how it is obtained.

Te supernatural (Medieval Latin: supernātūrālis: supra "above" + naturalis "natural", frst used: 1520–1530 AD) are those things, or things that have been claimed to exist, which cannot be explained by the laws of nature, including things characteristic of or relating to ghosts, gods, or other types of spirits and other non-material beings, or to things beyond nature. 53 Tings such as lightning which were once though to be supernatural have been shown to be entirely naturalistic, and some people claim that there is nothing supernatural. Such people maintain a skeptical attitude and belief. At least one prize for proving the existence of any supernatural thing at all remains unclaimed.

Traditionally, spirituality refers to a religious process of re-formation which "aims to recover the original shape of man," oriented at "the image of God" as exemplifed by the founders and sacred texts of the religions of the world. In modern times the emphasis is on subjective experience of a sacred dimension and the "deepest values and meanings by which people live, often in a context separate from organized religious institutions. Modern systems of spirituality may include a belief in a supernatural (beyond the known and observable) realm, personal growth, a quest for an ultimate or sacred meaning, religious experience, or an encounter with one's own "inner dimension”.

Te meaning of spirituality has developed and expanded over time, and various connotations can be found alongside each other. Te term "spirituality" originally developed within early Christianity, referring to a life oriented toward the Holy Spirit. During late medieval times the meaning broadened to include mental aspects of life, while in modern times the term both spread to other religious traditions and broadened to refer to a wider range of experience, including a range of esoteric traditions.

Marriage, also called matrimony or wedlock, a true wedding is between eternal partners and is a socially or ritually recognised union between spouses that establishes rights and obligations between those spouses, as well as between them and any resulting biological or adopted children and aﬃnity. Te defnition of marriage varies around the world not only between cultures and between religions, but also throughout the history of any given culture and religion, evolving to both expand and constrict in who and what is encompassed, but typically it is principally an institution in which interpersonal relationships, usually sexual, are acknowledged or sanctioned. In some cultures, marriage is recommended or considered to be compulsory before pursuing any sexual activity. When defned broadly, marriage is considered a cultural universal. A marriage ceremony is known as a wedding.

Marriage can be recognized by a state, an organization, a religious authority, a tribal group, a local community, or peers. It is often viewed as a contract. When a marriage is performed and carried out by a government institution in accordance with the marriage laws of the jurisdiction, without religious content, it is a civil marriage. Civil marriage recognizes and creates the rights and obligations intrinsic to matrimony before the state. When a marriage is performed with religious content under the auspices of a religious institution it is a religious marriage. Religious marriage recognizes and creates the rights and obligations intrinsic to matrimony before that religion. Religious marriage is known variously as sacramental marriage in Catholicism, nikah in Islam, nissuin in Judaism, and various other names in other faith traditions, each with their own constraints as to what constitutes, and who can enter into, a valid religious marriage.

Orthodoxy (from Greek ορθοδοξία, orthodoxía – "right opinion") is adherence to correct or accepted creeds, especially in religion. In the Christian sense the term means "conforming to the Christian faith as represented in the creeds of the early Church." Te frst seven Ecumenical Councils were held between the years of 325 and 787 with the aim of formalizing accepted doctrines.

In some English speaking countries, Jews who adhere to all the traditions and commandments of the Torah are often called Orthodox Jews, although the term "orthodox" historically frst described Christian beliefs.

Eschatology /ˌɛskəˈtɒlədʒi/ is a part of theology concerned with the fnal events of history, or the ultimate destiny of humanity. Tis concept is commonly referred to as the "end of the world" or "end times".

Te word arises from the Greek ἔσχατος eschatos meaning "last" and -logy meaning "the study of", frst used in English around 1844. Te Oxford English Dictionary defnes eschatology as "the part of theology concerned with death judgment, and the fnal destiny of the soul and of humankind".

In the context of mysticism, the phrase refers metaphorically to the end of ordinary reality and reunion with the Divine. In many religions it is taught as an existing future event prophesied in sacred texts or folklore.

History is often divided into "ages" (aeons), which are time periods each with certain commonalities. One age comes to an end and a new age or world to come, where diﬀerent realities are present, begins. When such transitions from one age to another are the subject of eschatological discussion, the phrase, "end of the world", is replaced by "end of the age", "end of an era", or "end of life as we know it". Much apocalyptic fction does not deal with the "end of time" but rather with the end of a certain period of time, the end of life as it is now, and the beginning of a new period of time. It is usually a crisis that

54 brings an end to current reality and ushers in a new way of living, thinking, or being. Tis crisis may take the form of the intervention of a deity in history, a war, a change in the environment, or the reaching of a new level of consciousness.

Most modern eschatology and apocalypticism, both religious and secular, involve the violent disruption or destruction of the world; whereas Christian and Jewish eschatologies view the end times as the consummation or perfection of God's creation of the world, albeit with violent overtures, such as the Great Tribulation.

For example, according to some ancient Hebrew worldviews, reality unfolds along a linear path (or rather, a spiral path, with cyclical components that nonetheless have a linear trajectory); the world began with God and is ultimately headed toward God's fnal goal for creation, the world to come.

Eschatologies vary as to their degree of optimism or pessimism about the future. In some eschatologies, conditions are better for some and worse for others, e.g. "heaven and hell".

Apocalypticism is the religious belief that there will be an apocalypse, a term which originally referred to a revelation of God's will, but now usually refers to the belief that the end of the world is imminent, even within one's own lifetime. Tis belief is usually accompanied by the idea that civilization will soon come to a tumultuous end due to some sort of catastrophic global event.

Apocalypticism is often conjoined with the belief that esoteric knowledge that will likely be revealed in a major confrontation between good and evil forces, destined to change the course of history. Apocalypses can be viewed as good, evil, ambiguous or neutral, depending on the particular religion or belief system promoting them. Tey can appear as a personal or group tendency, an outlook or a perceptual frame of reference, or merely as expressions in a speaker's rhetorical style.

A vision is something seen in a dream, trance, or religious ecstasy, especially a supernatural appearance that usually conveys a revelation. Visions generally have more clarity than dreams, but traditionally fewer psychological connotations. Visions are known to emerge from spiritual traditions and could provide a lens into human nature and reality. Prophecy is often associated with visions.

In simple words, it is a religious experience in which the experience can be seen and hence it is called a vision. Trance denotes any state of awareness or consciousness other than normal waking consciousness. Trance states may occur involuntarily and unbidden.

Te term trance may be associated with ailments, hypnosis, meditation, magic, fow, and prayer. It may also be related to the earlier generic term, altered states of consciousness.

Folklore is the expressive body of culture shared by a particular group of people; it encompasses the traditions common to that culture, subculture or group. Tese include oral traditions such as tales, proverbs and jokes. Tey include material culture, ranging from traditional building styles to handmade toys common to the group. Folklore also includes customary lore, the forms and rituals of celebrations such as Christmas and weddings, folk dances and initiation rites. Each one of these, either singly or in combination, is considered a folklore artifact. Just as essential as the form, folklore also encompasses the transmission of these artifacts from one region to another or from one generation to the next. For folklore is not taught in a formal school curriculum or studied in the fne arts. Instead these traditions are passed along informally from one individual to another either through verbal instruction or demonstration. Te academic study of folklore is called folkloristics.

In folklore, a ghost (sometimes known as an apparition, haunt, phantom, poltergeist, shade, specter or spectre, spirit, spook, and wraith) is the soul or spirit of a dead person or animal that can appear to the living. Descriptions of ghosts vary widely from an invisible presence to translucent or barely visible wispy shapes, to realistic, lifelike visions. Te deliberate attempt to contact the spirit of a deceased person is known as necromancy, or in spiritism as a séance.

Old wives' tale is a term used to indicate that a supposed truth is actually spurious or a superstition. It can be said sometimes to be a type of urban legend, said to be passed down by older women to a younger generation. Such tales are considered superstition, folklore or unverifed claims with exaggerated and/or inaccurate details. Old wives' tales often center on women's traditional concerns, such as pregnancy, puberty, social relations, health, herbalism and nutrition.

An urban legend, urban myth, urban tale, or contemporary legend is a form of modern folklore. It usually consists of fctional stories, often presented as true, with macabre or humorous elements, rooted in local popular culture. Tese legends

55 can be used for entertainment purposes, as well as semi-serious explanations for random events such as disappearances and strange objects.

Urban legends are spread by any media, including newspapers, e-mail and social media. Some urban legends have passed through the years with only minor changes to suit regional variations. More recent legends tend to refect modern circumstances, like the story of people ambushed and anesthetized, who awaken minus one kidney, which was supposedly surgically removed for transplantation.

Te belief in the existence of an afterlife, as well as manifestations of the spirits of the dead is widespread, dating back to animism or ancestor worship in pre- literate cultures. Certain religious practices—funeral rites, exorcisms, and some practices of spiritualism and ritual magic—are specifcally designed to rest the spirits of the dead. Ghosts are generally described as solitary, human-like essences, though stories of ghostly armies and the ghosts of animals rather than humans have also been recounted. Tey are believed to haunt particular locations, objects, or people they were associated with in life.

Magic via mysticism it believes that really magic is love and love is magic (Merlin Pendragon). Anything else is tragic. Magic represents a category used in the study of religion and the social sciences to defne various practices and ideas considered separate to both religion and science. Te category developed in Western culture although has since been applied to practices in other societies, particularly those regarded as being non-modern and Other. Various diﬀerent defnitions of magic have been proposed, with much contemporary scholarship regarding the concept to be so problematic that it is better to reject it altogether as a useful analytic construct.

Te concept of magic has been an issue of debate among academics in various disciplines. Scholars have defned magic in diﬀerent ways and used the term to refer to diﬀerent things. One approach, associated with the anthropologists Edward Tylor and James G. Frazer, suggests that magic and science are opposites, with the former based on hidden sympathies between objects that allow one to infuence the other. An alternative approach, associated with the sociologists Marcel Mauss and Emile Durkheim, emphasises an opposition between magic and religion, arguing that the former takes place in private, while the latter is a communal and organised activity. Many scholars of religion have rejected the utility of the term magic, arguing that it is arbitrary and ethnocentric; it has become increasingly unpopular within scholarship since the 1990s. Magic can be easily encountered via the ailment chemistry in perception and imagination and bodily - look out for the trip!

Te term magic comes from the Old Persian magu, a word that applied to a form of religious functionary about which little is known. During the late sixth and early ffth centuries BCE, this term was adopted into Ancient Greek, where it was used with negative connotations, to apply to religious rites that were regarded as fraudulent, unconventional, and dangerous. Tis meaning of the term was then adopted by Latin in the frst century BCE. Te concept was then incorporated into Christian theology during the frst century CE, where magic was associated with demons and thus defned against religion. Tis concept was pervasive throughout the Middle Ages, when Christian authors categorised practices such as enchantment and divination under the label of magic. In early modern Europe, Italian humanists reinterpreted the term in a positive sense to establish the idea of natural magic. Both negative and positive understandings of the term were retained in Western culture over the following centuries, with the former largely infuencing early academic usages of the word.

A ritual "is a sequence of activities involving gestures, words, and objects, performed in a sequestered place, and performed according to set sequence". Rituals may be prescribed by the traditions of a community, including a religious community. Rituals are characterized but not defned by formalism, traditionalism, invariance, rule-governance, sacral symbolism, and performance.

Rituals are a feature of all known human societies. Tey include not only the worship rites and sacraments of organized religions and cults, but also rites of passage, atonement and purifcation rites, oaths of allegiance, dedication ceremonies, coronations and presidential inaugurations, marriages and funerals, school "rush" traditions and graduations, club meetings, sporting events, Halloween parties, veterans parades, Christmas shopping and more. Many activities that are ostensibly performed for concrete purposes, such as jury trials, execution of criminals, and scientifc symposia, are loaded with purely symbolic actions prescribed by regulations or tradition, and thus partly ritualistic in nature. Even common actions like hand- shaking and saying healo may be termed rituals.

Troughout Western history, there have been examples of individuals who engaged in practices that their societies called magic and who sometimes referred to themselves as magicians. Within modern occultism, there are many self-described magicians and people who practice magic. In this environment, the concept of magic has again changed, usually being defned as a technique for bringing about changes in the physical world through the force of one's will. Tis defnition was

56 pioneered largely by the infuential British occultist Aleister Crowley, who defned the term as magick and who had been infuenced by various magic-related anthropological discussions and personal practices.

Sacred means revered due to sanctity and is generally the state of being perceived by religious individuals as associated with divinity and considered worthy of spiritual respect or devotion; or inspiring awe or reverence among believers.

Objects are often considered sacred if used for spiritual purposes, such as the worship or service of gods. Te property is often ascribed to objects (a "sacred artifact" that is venerated and blessed), or places ("sacred ground”).

Q-D-Š is a triconsonantal Semitic root meaning "sacred, holy", derived from a concept central to ancient Semitic religion. From a basic verbal meaning "to consecrate, to purify", it could be used as an adjective meaning "holy", or as a substantive referring to a "sanctuary, sacred object, sacred personnel."

in Central and South Semitic. In (قدس in Northwest Semitic and as qds (Arabic (קדש Te root is refected as qdš (Hebrew Akkadian texts, the verb conjugated from this root meant to "clean, purify.”

An omen (also called portent or presage) is a phenomenon that is believed to foretell the future, often signifying the advent of change. People in the ancient times believed that omens lie with a divine message from their gods.

Tese omens include natural phenomena, for example an eclipse, abnormal births of animals and humans and behavior of the sacrifcial lamb on its way to the slaughter. Tey had specialists, the diviners, to interpret these omens. Tey would also use an artifcial method, for example, a clay model of a sheep liver, to communicate with their gods in times of crisis. Tey would expect a binary answer, either yes or no answer, favorable or unfavorable. Tey did these to predict what would happen in the future and to take action to avoid disaster.

Tough the word "omen" is usually devoid of reference to the change's nature, hence being possibly either "good" or "bad," the term is more often used in a foreboding sense, as with the word "ominous". Te origin of the word is unknown, although it may be connected with the Latin word audire, meaning "to hear."

Paradise is the term for a place of timeless harmony. Te Abrahamic faiths associate paradise with the Garden of Eden, that is, the perfect state of the world prior to the fall from grace, and the perfect state that will be restored in the World to Come.

Paradisaical notions are cross-cultural, often laden with pastoral imagery, and may be cosmogonical or eschatological or both, often compared to the miseries of human civilization: in paradise there is only peace, prosperity, and happiness. Paradise is a place of contentment, a land of luxury and fulfllment. Paradise is often described as a "higher place", the holiest place, in contrast to this world, or underworlds such as Hell. In eschatological contexts, paradise is imagined as an abode of the virtuous dead. In Christian and Islamic understanding, Heaven is a paradisaical relief. In old Egyptian beliefs, the otherworld is Aaru, the reed-felds of ideal hunting and fshing grounds where the dead lived after judgment. For the Celts, it was the Fortunate Isle of Mag Mell. For the classical Greeks, the Elysian felds was a paradisaical land of plenty where the heroic and righteous dead hoped to spend eternity. Te Vedic Indians held that the physical body was destroyed by fre but recreated and reunited in the Tird Heaven in a state of bliss. In the Zoroastrian Avesta, the "Best Existence" and the "House of Song" are places of the righteous dead. On the other hand, in cosmological contexts 'paradise' describes the world before it was tainted by evil.

Cleromancy is a form of sortition, casting of lots, in which an outcome is determined by means that normally would be considered random, such as the rolling of dice, but are sometimes believed to reveal the will of God, or other supernatural entities.

Temenos (Greek: τέμενος; plural: τεμένη, temene) is a piece of land cut off and assigned as an official domain, especially to kings and chiefs, or a piece of land marked off from common uses and dedicated to a god, a sanctuary, holy grove or holy precinct: the Pythian race-course is called a temenos, the sacred valley of the Nile is the Νείλοιο πῖον τέμενος Κρονίδα ("the rich temenos of Cronides by the Nile"), the Acropolis of Athens is the ἱερὸν τέμενος ("the holy temenos"; of Pallas). Te word derives from the Greek verb τέμνω (temnō), "to cut". Te earliest attested form of the word is the Mycenaean Greek te-me-nostrum.

Te concept of temenos arose in classical Mediterranean cultures as an area reserved for worship of the gods. Some authors have used the term to apply to a sacred grove of trees, isolated from everyday living spaces, while other usage points to areas within ancient urban development that are parts of sanctuaries.

57 A temenos is often physically marked by a Peribolos fence or wall (e.g. Delphi) as a structural boundary. A temenos enclosed a sacred space called a hieron; all things inside of this area belonged to the god. Greeks could fnd asylum within a sanctuary and be under the protection of the deity and could not be moved against their will.

A large example of a Bronze Age Minoan temenos is at the Juktas Sanctuary of the palace of Knossos on ancient Crete in present-day Greece, the temple having a massive northern temenos. Another example is at Olympia, the temenos of Zeus. Tere were many temene of Apollo, as he was the patron god of settlers.

In religious discourse in Banoshie, temenos has also come to refer to a territory, plane, receptacle or feld of deity or divinity.

C. G. Jung relates the temenos to the spellbinding or magic circle, which acts as a 'square space' or 'safe spot' where mental 'work' can take place. Tis temenos resembles among others a 'symmetrical rose garden with a fountain in the middle' (the 'squared circle') in which an encounter with the unconscious can be had and where these unconscious contents can safely be brought into the light of consciousness. In this manner one can meet one's own Shadow, Animus/Anima, Wise Old Wo/ Man (Senex) and fnally the Self, names that Jung gave to archetypal personifcations of (unpersonal) unconscious contents which seem to span all cultures.

Immortality of the soul, Te orthodox Christian belief about the Intermediate state between death and Judgment Day is immortality of the soul followed immediately after death of the body by Particular Judgment. In Catholicism some souls temporarily stay in Purgatory to be purifed for Heaven (as described in the Catechism of the Roman Catholic Church, 1030–32). Eastern Orthodoxy, Methodism, Anglicanism, and Mormonism use different terminology, but generally teach that the soul waits in the Abode of the Dead, specifcally Hades or the Spirit World, until the Resurrection of the Dead, the saved resting in light and the damned suffering in darkness. According to James Tabor this Eastern Orthodox picture of Particular Judgment is similar to the frst-century Jewish and possibly Early Christian concept that the dead either "Rest in Peace" in the Bosom of Abraham (mentioned in the Gospel of Luke) or suffer in Hades. Tis view was also promoted by John Calvin, though Calvin taught that immortality was not in the nature of the soul but was imparted by God. Nineteenth-century Reformed theologians such as A.A. Hodge, W.G.T. Shedd, and Louis Berkhof also taught the immortality of the soul, but some later Reformed theologians such as Herman Bavinck and G. C. Berkouwer rejected the idea as unscriptural. Psient believes that as soon as the body turns to a nerd (nobody ever really dies) the mind and spirit transverse to the heavenly life to the add a layer too the soul tree, a documentary of that life; that soul is immortal, so can be body, take care of it.

Opponents of Psychopannychism (soul sleeping) and Tnetopsychism (the temporary death of the soul) include the Roman Catholic Church, most mainline Protestant denominations, and most conservative Protestants, Evangelicals, and Fundamentalists.

Resurrection is the concept of coming back to life after death. In a number of ancient religions, a dying-and-rising god is a deity which dies and resurrects. Te death and resurrection of Jesus, an example of resurrection, is the central focus of Christianity. As a religious concept, it is used in two distinct respects: a belief in the resurrection of individual souls that is current and ongoing (Christian idealism, realized eschatology), or else a belief in a singular resurrection of the dead at the end of the world. Te resurrection of the dead is a standard eschatological belief in the Abrahamic religions. Some believe the soul is the actual vehicle by which people are resurrected. Christian theological debate ensues with regard to what kind of resurrection is factual – either a spiritual resurrection with a spirit body into Heaven, or a material resurrection with a restored human body. While most Christians believe Jesus' resurrection from the dead and ascension to Heaven was in a material body, a very small minority believe it was spiritual. Tere are documented rare cases of the return to life of the clinically dead which are classifed scientifcally as examples of the Lazarus syndrome, a term originating from the Biblical story of the Resurrection of Lazarus. Resurrection is a Miracle of the highest order and can be done from dust. Tere are spiritual means of resurrecting ancestors through telepathy for discussion; after even the most horrifc of passings’s, it only takes the right duration of prayer.

Reincarnation is the philosophical or religious concept that an aspect of a living being starts a new life in a diﬀerent physical body or form after each biological death. It is also called rebirth or transmigration, and is a part of the Saṃsāra doctrine of cyclic existence. It is a central tenet of all major Indian religions, namely Buddhism, Hinduism, Jainism, and Sikhism. Te idea of reincarnation is found in many ancient cultures, and a belief in rebirth/metempsychosis was held by Greek historic fgures, such as Pythagoras, Socrates, and Plato. It is also a common belief of various ancient and modern religions such as Spiritism, Teosophy, and Eckankar and is found as well in many tribal societies around the world, in places such as Australia, East Asia, Siberia, and South America.

58 Although the majority of denominations within the Abrahamic religions of Judaism, Christianity, and Islam do not believe that individuals reincarnate, particular groups within these religions do refer to reincarnation; these groups include the mainstream historical and contemporary followers of Kabbalah, the Cathars, Alawites, the Druze, and the Rosicrucians. Te historical relations between these sects and the beliefs about reincarnation that were characteristic of Neoplatonism, Orphism, Hermeticism, Manicheanism, and Gnosticism of the Roman era as well as the Indian religions have been the subject of recent scholarly research. Unity Church and its founder Charles Fillmore teach reincarnation.

In recent decades, many Europeans and North Americans have developed an interest in reincarnation, and many contemporary works mention it.

Death is the cessation of all biological functions that sustain a living organism. Phenomena which commonly bring about death include aging, predation, malnutrition, disease, suicide, homicide, starvation, dehydration, and accidents or trauma resulting in terminal injury. In most cases, bodies of living organisms begin to decompose shortly after death. Psient proposes that the body turns into a Nerd (nobody ever really dies) this dying becomes nerding.

Death – particularly the death of humans – has commonly been considered a sad or unpleasant occasion, due to the aﬀection for the being that has died and the termination of social and familial bonds with the deceased. Other concerns include fear of death, necrophobia, anxiety, sorrow, grief, emotional pain, depression, sympathy, compassion, solitude, or saudade. Many cultures and religions have the idea of an afterlife, and also hold the idea of reward or judgement and punishment for past sin. In the spirit travels into the afterlife and leaves the body behind after a funeral in a place of tranquility and peace;; from there the spirit depending on its life actions can go too the next paradigm, hopefully heaven.

Teotokos (Greek Θεοτόκος Greek pronunciation: [θeoˈtokos is a title of Mary, mother of God, used especially in Eastern Christianity. Te usual Latin translations, Dei Genetrix or Deipara (approximately "parent (fem.) of God"), are translated as "Mother of God" or “God-bearer".

Teotokos is also used as the term for an Eastern icon, or type of icon, of the Mother with Child (in the western tradition typically called a Madonna), as in "the Teotokos of Vladimir" both for the original 12th-century icon and for icons that are copies or imitate its composition.

Te title of Mother of God (Greek Μήτηρ (του) Θεοῦ; abbreviated ΜΡ ΘΥ, Latin Mater Dei) (and equivalents) is most often used in English (and other modern western languages), largely due to the lack of a satisfactory equivalent of Greek τόκος / Latin genetrix. Contemporary use of Mother of God often denotes ‘something’ bigger than god’ tho this is impossible.

Greek mythology is the body of myths and teachings that belong to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and signifcance of their own cult and ritual practices. It was a part of the religion in ancient Greece. Modern scholars refer to and study the myths in an attempt to shed light on the religious and political institutions of ancient Greece and its civilisation, and to gain understanding of the nature of myth-making itself.

Greek mythology has had an extensive infuence on the culture, arts, and literature of Western civilisation and remains part of Western heritage and language. Poets and artists from ancient times to the present have derived inspiration from Greek mythology and have discovered contemporary signifcance and relevance in the themes.

Greek mythology is explicitly embodied in a large collection of narratives, and implicitly in Greek representational arts, such as ancient vase-paintings and votive gifts. Greek myth attempts to explain the origins of the world, and details the lives and adventures of a wide variety of gods, goddesses, heroes, heroines and mythological creatures. Tese accounts initially were disseminated in an oral-poetic tradition; today the Greek myths are known primarily from ancient Greek literature. Te oldest known Greek literary sources, Homer's epic poems Iliad and Odyssey, focus on the Trojan War and its aftermath. Two poems by Homer's near contemporary Hesiod, the Teogony and the Works and Days, contain accounts of the genesis of the world, the succession of divine rulers, the succession of human ages, the origin of human woes, and the origin of sacrifcial practices. Myths are also preserved in the Homeric Hymns, in fragments of epic poems of the Epic Cycle, in lyric poems, in the works of the tragedians and comedians of the ffth century BC, in writings of scholars and poets of the Hellenistic Age, and in texts from the time of the Roman Empire by writers such as Plutarch and Pausanias.

Archaeological fndings provide a principal source of detail about Greek mythology, with gods and heroes featured prominently in the decoration of many artifacts. Geometric designs on pottery of the eighth century BC depict scenes from the Trojan cycle as well as the adventures of Heracles. In the succeeding Archaic, Classical, and Hellenistic periods, Homeric and various other mythological scenes appear, supplementing the existing literary evidence. 59 A Christian is someone who follows the religion of Christmas and its holy order, there is no specifc prophet and christian like Buddism and Sikhism and Elopes are all earth religions.

While there are diverse interpretations of Christianity which sometimes confict, they are united in believing that Jesus has a unique signifcance. Te term "Christian" is also used as an adjective to describe anything associated with Christianity, or in a proverbial sense "all that is noble, and good, and Christ-like.”. Any mortal can become Christ, but you must be good and it is a competition, whoever wins is nominated by god who tells the archbishops and then they are celebrated on Christmas day.

Te Manifestations of God are not seen as incarnations of God as God cannot be divided and does not descend to the condition of his creatures, but they are also not seen as ordinary mortals. Instead, the Bahá'í concept of a Manifestation of God emphasizes the simultaneously existing qualities of humanity and divinity. In the station of divinity, they show forth the will, knowledge and attributes of God; in the station of humanity, they show the physical qualities of common man.[1] A common Bahá'í analogy used to explain the relationship between the Manifestation of God and God is that of a perfect mirror. In the analogy, God is likened to the Sun – the source of physical life on earth. Te spirit and attributes of God are likened to the rays of the Sun, and the Manifestations of God are likened to perfect mirrors refecting the rays of the Sun.[2] Tus, the Manifestations of God act as pure mirrors that refect the attributes of God onto this material world.[1]

Te Manifestations of God are seen to represent a level of existence which is an intermediary between God and humans. Bahá'u'lláh, the founder of the Bahá'í Faith, explained that at one extreme the Manifestations of God are humble servants of God and at the other extreme they claim to speak with the voice of God, and manifest his attributes to humanity. Tey may at times emphasize their humanity, and at other times proclaim their divinity. Tese stations are complementary rather than mutually exclusive.[1]

Te Manifestations of God are believed to possess capacities that do not exist in humans, and this difference is not a difference in degree but a difference in kind. Te Manifestations of God are not seen to be simply great thinkers or philosophers who have a better understanding than others, but that, by their nature, they are inherently superior to the average human.[6] Tus, the Manifestations of God are special beings, having a unique relationship to God as they have been sent by God from the spiritual world as an instrument of divine revelation. Tey are understood to have existed in the spiritual world prior to their physical birth in this life. Tey are also seen to have innate, divinely revealed knowledge and absolute knowledge of the physical world.[6] According to Àbdu'l-Bahá, the son and successor of the founder of the Bahá'í Faith, the Manifestations of God must be distinguished above any other person in every aspect and qualifcation, in order that they can effectively train and educate people.[7]

An innate quality or ability is one that you were born with, not one you have learned

Incarnation literally means embodied in fesh or taking on fesh. It refers to the conception and birth of a sentient being who is the material manifestation of an entity, god or force whose original nature is immaterial. In its religious context the word is used to mean the descent from Heaven of a god, deity, or divine being in human/animal form on Earth.

Sentience is the capacity to feel, perceive or experience subjectively.[1] Eighteenth-century philosophers used the concept to distinguish the ability to think (reason) from the ability to feel (sentience). In modern Western philosophy, sentience is the ability to experience sensations (known in philosophy of mind as "qualia"). In Eastern philosophy, sentience is a metaphysical quality of all things that require respect and care. Te concept is central to the philosophy of animal rights because sentience is necessary for the ability to suﬀer, and thus is held to confer certain rights.

Consecration is the solemn dedication to a special purpose or service, usually religious. Te word consecration literally means "association with the sacred". Persons, places, or things can be consecrated, and the term is used in various ways by diﬀerent groups. Te origin of the word comes from the Latin word consecrat, which means dedicated, devoted, and sacred.[1] A synonym for to consecrate is to sanctify; a distinct antonym is to desecrate.

Te Manifestation of God is a concept in the Bahá'í Faith that refers to what are commonly called prophets. Te Manifestations of God are appearances of the Divine Spirit or Holy Spirit in a series of personages, and as such, they perfectly refect the attributes of the divine into the human world for the progress and advancement of human morals and civilization through the agency of that same Spirit.[1] In the Baha'i Faith, it is believed that the Manifestations of God are the only channel for humanity to know about God because contact with the Spirit is what transforms the heart and mind, creating a living relationship between the soul and God. Tey act as perfect mirrors refecting the attributes of God into the physical world.[2] Bahá'í teachings hold that the motive force in all human development is due to the coming of the Manifestations of God.[3] Te Manifestations of God are directly linked with the Bahá'í concept of progressive revelation. 60 Apostles are like Prophets and constantly update the religions of god from age to age, occasionally an Apostle can be a Prophet, you will see and hear of them through revelations of God.

61 5) Mind -Psychology, Body-Physiology & Soul - Philosophy

1 - Psychology - Mind

Psychology is the science of behavior and mind, including conscious and unconscious phenomena, as well as thought. It is an academic discipline of immense scope and diverse interests that, when taken together, seek an understanding of the emergent properties of brains, and all the variety of epiphenomena they manifest. As a social science it aims to understand individuals and groups by establishing general principles and researching specifc cases.

You psychology is fundamental to healing and well-being, as discusses in the Law’s as soon as you break the law of love you will damage your psychology and you will suﬀer, swear words can do this easily be careful with they’re use. Psychology is the one to watch all the time, by understanding your emotions and your behaviour you will be able to understand how you react to situations; thus you should be able with a little more insight from Psient - be able to manage you psychology with ease. On good days life drift’s by like a good high, on bad days your emotions run wild, even boredom can take over which can depress the mind, brain and body and feel draining. Exercise can help as well s talking or reading, or doing something constructive. Tere are many suggestion in this book for things to say and do with others.

In this feld, a professional practitioner or researcher is called a psychologist and can be classifed as a social, behavioral, or cognitive scientist. Psychologists attempt to understand the role of mental functions in individual and social behavior, while also exploring the physiological and biological processes that underlie cognitive functions and behaviors.

Psychologists explore behavior and mental processes, including perception, cognition, attention, emotion (aﬀect), intelligence, phenomenology, motivation (conation), brain functioning, and personality. Tis extends to interaction between people, such as interpersonal relationships, including psychological resilience, family resilience, and other areas. Psychologists of diverse orientations also consider the unconscious mind. Psychologists employ empirical methods to infer causal and correlational relations` matters such as existence, knowledge, values, reason, mind, and language. Te term was probably coined by Pythagoras (c. 570–495 BCE). Philosophical methods include questioning, critical discussion, rational argument, and systematic presentation. Classic philosophical questions include: Is it possible to know anything and to prove it? What is most real? Philosophers also pose more practical and concrete questions such as: Is there a best way to live? Is it better to be just or unjust (if one can get away with it)? Do humans have free will? Mind is the soft of the brain hard - .Use Proto-Creation any where on the body, with Prayer. � Te human is a cosmological body; that has a spirit that is eternal and a soul that is eternal. If the Spirit is in Alignment with the body all is considered well.

Te mind can, for example: use: - Astral projection (or astral travel) is a term used in esotericism to describe a willful out-of- body experience (OBE) that assumes the existence of a soul or consciousness called an "astral body" that is separate from the physical body and capable of travelling outside it throughout the universe too make observations. In the advancing stages leading to the beginning of the path, the aspirant becomes spiritually prepared for being entrusted with free use of the forces of the inner world of the astral bodies. He may then undertake astral journeys in his astral body, leaving the physical body in sleep or wakefulness. Te astral journeys that are taken unconsciously are much less important than those undertaken with full consciousness and as a result of deliberate volition. Tis implies conscious use of the astral body. Conscious separation of the astral body from the outer vehicle of the gross body has its own value in making the soul feel its distinction from the gross body and in arriving at fuller control of the gross body. One can, at will, put on and take oﬀ the external gross body as if it were a cloak, and use the astral body for experiencing the inner world of the astral and for undertaking journeys through it, if and when necessary....Te ability to undertake astral journeys therefore involves considerable expansion of one’s scope for experience. It brings opportunities for promoting one’s own spiritual advancement, which begins with the involution of consciousness:. Te Indian spiritual teacher Meher Baba described one's use of astral projection. Tis could form a world view of an individual. Tis creates says Baba, ‘involution’:- is the inner path of the human soul to the Self. Charles Haynes, in describing Meher Baba's sense of involution writes, "Te old and new impressions, both of which create a veil over consciousness, gradually wear away, revealing an increasingly clearer experience of God; that is, the soul wearies of the world and is ready to begin the third phase of the journey, involution, which may be seen as the 'ascent' back to God. Impressions and expressions of perception and memory distilling in time.

Tought is composed of the perception and datum and quaila from the senses and takes place in the mind and or the brain - hard and soft ware tho of a very diﬀerent nature to that digital. Further the word the language of thought sometimes known as thought ordered mental expression,[2] is a view in linguistics, philosophy of mind and near and cognition. It describes the nature of thought as processing "language-like" or compositional structure sometimes known as the ‘mental’.

62 On this view, simple concepts combine in systematic ways (akin to the rules of grammar in language) to build thoughts. In its most basic form, the theory states that thought, like language, has syntax and a complex math.

Using empirical data drawn from linguistics and cognitive ability to describe mental representation from a philosophical vantage-point, the hypothesis states that thinking takes place in a language of thought : cognition and cognitive processes are only 'remotely plausible' when expressed as a system of representations that is "tokened" by a linguistic or semantic structure and operated upon by means of a combinatorial syntax. Linguistic tokens used in mental language describe elementary concepts which are operated upon by logical rules establishing causal connections to allow for complex thought. Syntax as well as semantics have a causal eﬀect on the properties of this system of mental representations.

Consciousness and the cosmos meet here as does time and space as well as many other cosmic mysteries of spiritual and physical life forms and functions. meme are particles of thought with meta physical experession. RNA is particularly aﬀected by thought. Substance and materials also have potence and feeling. Meaning and matter, logic and reason too.

Illusion is a mixture of conceptive and imaginative traits set by a broadcast of empirical wonder, illusions are supported by tranquility, peace and perfection.

Te somatosensory system is a part of the sensory nervous system. Te somatosensory system is a complex system of sensory neurons and neural pathways that responds to changes at the surface or inside the body. Te axons (as afferent nerve fibers) of sensory neurons connect with, or respond to, various receptor cells. Tese sensory receptor cells are activated by different stimuli such as heat and nociception, giving a functional name to the responding sensory neuron, such as a thermoreceptor which carries information about temperature changes. Other types include mechanoreceptors, chemoreceptors, and nociceptors which send signals along a sensory nerve to the spinal cord where they may be processed by other sensory neurons and then relayed to the brain for further processing. Sensory receptors are found all over the body including the skin, epithelial tissues, muscles, bones and joints, internal organs, and the cardiovascular system.

Touch is a crucial means of receiving information. Somatic senses are sometimes referred to as somesthetic senses,[1] with the understanding that somesthesis includes the sense of touch, proprioception (sense of position and movement), and (depending on usage) haptic perception.[2] Te mapping of the body surfaces in the brain is called somatotopy. In the cortex, it is also referred to as the cortical homunculus. Tis brain-surface ("cortical") map is not immutable, however. Dramatic shifs can occur in response to stroke or injury.

Psychologists explore behavior and mental processes, including perception, cognition, attention, emotion (aﬀect), intelligence, phenomenology, motivation (conation), brain functioning, and personality. Tis extends to interaction between people, such as interpersonal relationships, including psychological resilience, family resilience, and other areas. Psychologists of diverse orientations also consider the unconscious mind. Psychologists employ empirical methods to infer causal and correlational relations` matters such as existence, knowledge, values, reason, mind, and language. Te term was probably coined by Pythagoras (c. 570– 495 BCE). Philosophical methods include questioning, critical discussion, rational argument, and systematic presentation. Classic philosophical questions include: Is it possible to know anything and to prove it? What is most real? Philosophers also pose more practical and concrete questions such as: Is there a best way to live? Is it better to be just or unjust (if one can get away with it)? Do humans have free will?

Instinct or innate behavior is the inherent inclination of a living organism towards a particular complex behavior. Te simplest example of an instinctive behavior is a fxed action pattern (FAP), in which a very short to medium length sequence of actions, without variation, are carried out in response to a corresponding clearly defned stimulus.

An instinctive behavior of shaking water from wet fur. A baby leatherback turtle makes its way to the open ocean Any behavior is instinctive if it is performed without being based upon prior experience (that is, in the absence of learning), and is therefore an expression of innate biological factors. Sea turtles, newly hatched on a beach, will automatically move toward the ocean. A marsupial climbs into its mother's pouch upon being born. Honeybees communicate by dancing in the direction of a food source without formal instruction. Other examples include animal fghting, animal courtship behavior, internal escape functions, and the building of nests. Tough an instinct is defned by its invariant innate characteristics, details of its performance can be changed by experience; for example, a dog can improve its fghting skills by practice.

Instincts are inborn complex patterns of behavior that exist in most members of the species, and should be distinguished from refexes, which are simple responses of an organism to a specifc stimulus, such as the contraction of the pupil in response to bright light or the spasmodic movement of the lower leg when the knee is tapped. Te absence of volitional capacity must not be confused with an inability to modify fxed action patterns. For example, people may be able to modify 63 a stimulated fxed action pattern by consciously recognizing the point of its activation and simply stop doing it, whereas animals without a suﬃciently strong volitional capacity may not be able to disengage from their fxed action patterns, once activated.

Behavior (late Middle English: from behave, on the pattern of demeanour, and infuenced by obsolete haviour from have.)or behaviour is the range of actions and mannerisms made by individuals, organisms, systems, or artifcial entities in conjunction with themselves or their environment,[2] which includes the other systems or organisms around as well as the (inanimate) physical environment. It is the computed response of the system or organism to various stimuli or inputs, whether internal or external, conscious or subconscious, overt or covert, and voluntary or involuntary. Taking a behavior informatics perspective, a behavior consists of behavior actor, operation, interactions, and their properties. A behavior can be represented as a behavior vector.

Emotion is any conscious experience characterized by intense mental activity and a certain degree of pleasure or displeasure. Scientifc discourse has drifted to other meanings and there is no consensus on a defnition. Emotion is often intertwined with mood, temperament, personality, disposition, and motivation. In some theories, cognition is an important aspect of emotion. Tose acting primarily on the emotions they are feeling may seem as if they are not thinking, but mental processes are still essential, particularly in the interpretation of events. For example, the realization of our believing that we are in a dangerous situation and the subsequent arousal of our body's nervous system (rapid heartbeat and breathing, sweating, muscle tension) is integral to the experience of our feeling afraid. Other theories, however, claim that emotion is separate from and can precede cognition.

Emotions are complex. According to some theories, they are states of feeling that result in physical and psychological changes that infuence our behavior. Te physiology of emotion is closely linked to arousal of the nervous system with various states and strengths of arousal relating, apparently, to particular emotions. Emotion is also linked to behavioral tendency. Extroverted people are more likely to be social and express their emotions, while introverted people are more likely to be more socially withdrawn and conceal their emotions. Emotion is often the driving force behind motivation, positive or negative. According to other theories, emotions are not causal forces but simply syndromes of components, which might include motivation, feeling, behavior, and physiological changes, but no one of these components is the emotion. Nor is the emotion an entity that causes these components.

Emotions involve different components, such as subjective experience, cognitive processes, expressive behavior, psychophysiological changes, and instrumental behavior. At one time, academics attempted to identify the emotion with one of the components: William James with a subjective experience, behaviorists with instrumental behavior, psychophysiologists with physiological changes, and so on. More recently, emotion is said to consist of all the components. Te different components of emotion are categorized somewhat differently depending on the academic discipline. In psychology and philosophy, emotion typically includes a subjective, conscious experience characterized primarily by psychophysiological expressions, biological reactions, and mental states. A similar multicomponential description of emotion is found in sociology. For example, Peggy Toits described emotions as involving physiological components, cultural or emotional labels (anger, surprise, etc.), expressive body actions, and the appraisal of situations and contexts.

Research on emotion has increased signifcantly over the past two decades with many felds contributing including psychology, neuroscience, endocrinology, medicine, history, sociology, and computer science. Te numerous theories that attempt to explain the origin, neurobiology, experience, and function of emotions have only fostered more intense research on this topic. Current areas of research in the concept of emotion include the development of materials that stimulate and elicit emotion. In addition PET scans and fMRI scans help study the aﬀective processes in the brain.

"Emotions can be defned as a positive or negative experience that is associated with a particular pattern of physiological activity." Emotions produce diﬀerent physiological, behavioral and cognitive changes. Te original role of emotions was to motivate adaptive behaviors that in the past would have contributed to the survival of humans. Emotions are responses to signifcant internal and external events.

Humour (British English) or humor (American English; see spelling diﬀerences) is the tendency of particular cognitive experiences to provoke laughter and provide amusement. Te term derives from the humoral medicine of the ancient Greeks, which taught that the balance of fuids in the human body, known as humours (Latin: humor, "body fuid"), controlled human health and emotion.

Sorrow is an emotion, feeling, or sentiment. Sorrow "is more 'intense' than sadness... it implies a long-term state".[1] At the same time "sorrow — but not unhappiness — suggests a degree of resignation... which lends sorrow its peculiar air of dignity”. Moreover, "in terms of attitude, sorrow can be said to be half way between sadness (accepting) and distress (not accepting)"

64 People of all ages and cultures respond to humour. Most people are able to experience humour—be amused, smile or laugh at something funny—and thus are considered to have a sense of humour. Te hypothetical person lacking a sense of humour would likely fnd the behaviour inducing it to be inexplicable, strange, or even irrational. Tough ultimately decided by personal taste, the extent to which a person fnds something humorous depends on a host of variables, including geographical location, culture, maturity, level of education, intelligence and context. For example, young children may favour slapstick such as Punch and Judy puppet shows or the Tom and Jerry cartoons, whose physical nature makes it accessible to them. By contrast, more sophisticated forms of humour such as satire require an understanding of its social meaning and context, and thus tend to appeal to a more mature audience.

Satire is a genre of literature, and sometimes graphic and performing arts, in which vices, follies, abuses, and shortcomings are held up to ridicule, ideally with the intent of shaming individuals, corporations, government, or society itself into improvement. Although satire is usually meant to be humorous, its greater purpose is often constructive social criticism, using wit to draw attention to both particular and wider issues in society.

A feature of satire is strong irony or sarcasm—"in satire, irony is militant"—but parody, burlesque, exaggeration, juxtaposition, comparison, analogy, and double entendre are all frequently used in satirical speech and writing. Tis "militant" irony or sarcasm often professes to approve of (or at least accept as natural) the very things the satirist wishes to attack.

Affection, attraction, infatuation, or fondness is a "disposition or state of mind or body" that is often associated with a feeling or type of love. It has given rise to a number of branches of philosophy and psychology concerning emotion, disease, infuence, and state of being. "Affection" is popularly used to denote a feeling or type of love, amounting to more than goodwill or friendship. Writers on ethics generally use the word to refer to distinct states of feeling, both lasting and spasmodic. Some contrast it with passion as being free from the distinctively sensual element. Even a very simple demonstration of affection can have a broad variety of emotional reactions, from embarrassment to disgust to pleasure and annoyance. It also has a different physical effect on the giver and the receiver.

Anger or wrath is an intense emotional response. It is an emotion that involves a strong uncomfortable and hostile response to a perceived provocation, hurt or threat. Anger can occur when a person feels their personal boundaries are being or are going to be violated. Some have a learned tendency to react to anger through retaliation as a way of coping. Raymond Novaco of University of California Irvine, who since 1975 has published a plethora of literature on the subject, stratifed anger into three modalities: cognitive (appraisals), somatic-affective (tension and agitations), and behavioral (withdrawal and antagonism). William DeFoore, an anger-management writer, described anger as a pressure cooker: we can only apply pressure against our anger for a certain amount of time until it explodes. Anger is an emotional reaction that impacts the body. A person experiencing anger will also experience physical conditions, such as increased heart rate, elevated blood pressure, and increased levels of adrenaline and noradrenaline. Some view anger as an emotion which triggers part of the fght or fight brain response. Anger is used as a protective mechanism to cover up fear, hurt or sadness. Anger becomes the predominant feeling behaviorally, cognitively, and physiologically when a person makes the conscious choice to take action to immediately stop the threatening behavior of another outside force. Te English term originally comes from the term anger of Old Norse language. Anger can have many physical and mental consequences. Te external expression of anger can be found in facial expressions, body language, physiological responses, and at times public acts of aggression. Some animals, for example, make loud sounds, attempt to look physically larger, bare their teeth, and stare. Te behaviors associated with anger are designed to warn aggressors to stop their threatening behavior. Rarely does a physical altercation occur without the prior expression of anger by at least one of the participants. While most of those who experience anger explain its arousal as a result of "what has happened to them," psychologists point out that an angry person can very well be mistaken because anger causes a loss in self- monitoring capacity and objective observability. Modern psychologists view anger as a primary, natural, and mature emotion experienced by virtually all humans at times, and as something that has functional value for survival. Anger is seen as a supportive mechanism to show a person that something is wrong and requires changing. Anger can mobilize psychological resources for corrective action. Uncontrolled anger can, however, negatively affect personal or social well-being and impact negatively on those around them. It is equally challenging to be around an angry person and the impact can also cause psychological/emotional trauma if not dealt with. While many philosophers and writers have warned against the spontaneous and uncontrolled fts of anger, there has been disagreement over the intrinsic value of anger. Te issue of dealing with anger has been written about since the times of the earliest philosophers, but modern psychologists, in contrast to earlier writers, have also pointed out the possible harmful effects of suppressing anger. Displays of anger can be used as a manipulation strategy for social infuence.

Angst means fear or anxiety (anguish is its Latinate equivalent, and anxious, anxiety are of similar origin). Te word angst was introduced into English from the Danish, Norwegian and Dutch word angst and the German word Angst. It is attested since the 19th century in English translations of the works of Kierkegaard and Freud. It is used in English to describe an intense feeling of apprehension, anxiety, or inner turmoil. In German, the technical terminology of psychology and

65 philosophy distinguishes between Angst and Furcht in that Furcht is a negative anticipation regarding a concrete threat, while Angst is a non-directional and unmotivated emotion. In common language, however, Angst is the normal word for "fear", while Furcht is an elevated synonym.

In other languages having the meaning of the Latin word pavor for "fear", the derived words diﬀer in meaning, e.g. as in the French anxiété and peur. Te word Angst has existed since the 8th century, from the Proto-Indo-European root *anghu-, "restraint" from which Old High German angust developed. It is pre- cognate with the Latin angustia, "tensity, tightness" and angor, "choking, clogging"; compare to the Ancient Greek ἄγχω (ankho) “strangle".

Anguish is a term used in philosophy, often as a translation from the Latin for angst. It is a paramount feature of existentialist philosophy, in which anguish is often understood as the experience of an utterly free being in a world with zero absolutes (existential despair). In the theology of Kierkegaard, it refers to a being with total free will who is in a constant state of spiritual fear that his freedom will lead him to fall short of the standards that God has laid out for them.

Annoyance is an unpleasant mental state that is characterized by such eﬀects as irritation and distraction from one's conscious thinking. It can lead to emotions such as frustration and anger.

Anticipation is an emotion involving pleasure, excitement, or anxiety in considering an expected event.

Anxiety is an emotion characterized by an unpleasant state of inner turmoil, often accompanied by nervous behavior, such as pacing back and forth, somatic complaints, and rumination. It is the subjectively unpleasant feelings of dread over anticipated events, such as the feeling of imminent death. Anxiety is not the same as fear, which is a response to a real or perceived immediate threat, whereas anxiety is the expectation of future threat. Anxiety is a feeling of uneasiness and worry, usually generalized and unfocused as an overreaction to a situation that is only subjectively seen as menacing. It is often accompanied by muscular tension, restlessness, fatigue and problems in concentration. Anxiety can be appropriate, but when experienced regularly the individual may suﬀer from an anxiety disorder. People facing anxiety may withdraw from situations which have provoked anxiety in the past. Tere are various types of anxiety. Existential anxiety can occur when a person faces angst, an existential crisis, or nihilistic feelings. People can also face mathematical anxiety, somatic anxiety, stage fright, or test anxiety. Social anxiety and stranger anxiety are caused when people are apprehensive around strangers or other people in general. Furthermore, anxiety has been linked with physical symptoms such as IBS and can heighten other mental health illnesses such as OCD and panic disorder. Te frst step in the management of a person with anxiety symptoms is to evaluate the possible presence of an underlying medical cause, whose recognition is essential in order to decide its correct treatment. Anxiety symptoms may be masking an organic disease, or appear associated or as a result of a medical disorder. Anxiety can be either a short term "state" or a long term "trait". Whereas trait anxiety represents worrying about future events, anxiety disorders are a group of mental disorders characterized by feelings of anxiety and fear. Anxiety disorders are partly genetic but may also be due to drug use, including alcohol, caﬀeine, and benzodiazepines (which are often prescribed to treat anxiety), as well as withdrawal from drugs of abuse. Tey often occur with other mental disorders, particularly bipolar disorder, eating disorders, major depressive disorder, or certain personality disorders. Common treatment options include lifestyle changes, medication, and therapy.

Apathy is a lack of feeling, emotion, interest, and concern. Apathy is a state of indiﬀerence, or the suppression of emotions such as concern, excitement, motivation, or passion. An apathetic individual has an absence of interest in or concern about emotional, social, spiritual, philosophical, or physical life and the world. Te apathetic may lack a sense of purpose, worth, or meaning in their life. An apathetic person may also exhibit insensibility or sluggishness. In positive psychology, apathy is described as a result of the individuals feeling they do not possess the level of skill required to confront a challenge (i.e. "fow"). It may also be a result of perceiving no challenge at all (e.g. the challenge is irrelevant to them, or conversely, they have learned helplessness). Apathy may be a sign of more specifc mental problems such as schizophrenia or dementia. However, apathy is something that all people face in some capacity. It is a natural response to disappointment, dejection, and stress. As a response, apathy is a way to forget about these negative feelings. Tis type of common apathy is usually only felt in the short-term and when it becomes a long-term or even lifelong state is when deeper social and psychological issues are most likely present. Apathy should be distinguished from reduced aﬀect, which refers to reduced emotional expression but not necessarily reduced emotion.

Arousal is the physiological and psychological state of being awoken or of sense organs stimulated to a point of perception. It involves activation of the ascending reticular activating system (ARAS) in the brain, which mediates wakefulness, the autonomic nervous system, and the endocrine system, leading to increased heart rate and blood pressure and a condition of sensory alertness, mobility, and readiness to respond. Arousal is mediated by several diﬀerent neural systems. Wakefulness is

66 regulated by the ARAS, which is composed of projections from fve major neurotransmitter systems that originate in the brainstem and form connections extending throughout the cortex; activity within the ARAS is regulated by neurons that release the neurotransmitters acetylcholine, norepinephrine, dopamine, histamine, and serotonin. Activation of these neurons produces an increase in cortical activity and subsequently alertness. Arousal is important in regulating consciousness, attention, alertness, and information processing. It is crucial for motivating certain behaviours, such as mobility, the pursuit of nutrition, the fght-or-fight response and sexual activity (the arousal phase of Masters and Johnson's human sexual response cycle). It is also important in emotion and has been included in theories such as the James-Lange theory of emotion. According to Hans Eysenck, diﬀerences in baseline arousal level lead people to be extraverts or introverts. Te Yerkes- Dodson law states that an optimal level of arousal for performance exists, and too little or too much arousal can adversely aﬀect task performance. One interpretation of the Yerkes-Dodson Law is the Easterbrook cue-utilisation hypothesis. Easterbrook states that an increase of arousal decreases the number of cues that can be used.

Awe is an emotion comparable to wonder but less joyous. On Robert Plutchik's wheel of emotions awe is modeled as a combination of surprise and fear. One dictionary defnition is "an overwhelming feeling of reverence, admiration, fear, etc., produced by that which is grand, sublime, extremely powerful, or the like: in awe of God; in awe of great political fgures.” Another dictionary defnition is a "mixed emotion of reverence, respect, dread, and wonder inspired by authority, genius, great beauty, sublimity, or might: We felt awe when contemplating the works of Bach. Te observers were in awe of the destructive power of the new weapon.” In general, awe is directed at objects considered to be more powerful than the subject, such as the Great Pyramid of Giza, the Grand Canyon, the vastness of the cosmos, or God.

In conventional usage, boredom is an emotional or psychological state experienced when an individual is left without anything in particular to do, is not interested in his or her surroundings, or feels that a day or period is dull or tedious. It is also understood by scholars as a modern phenomenon which has a cultural dimension. "Tere is no universally accepted defnition of boredom. But whatever it is, researchers argue, it is not simply another name for depression or apathy. It seems to be a specifc mental state that people fnd unpleasant—a lack of stimulation that leaves them craving relief, with a host of behavioural, medical and social consequences." According to BBC News, boredom "...can be a dangerous and disruptive state of mind that damages your health"; yet research "...suggest[s] that without boredom we couldn’t achieve our creative feats.” In Experience Without Qualities: Boredom and Modernity, Elizabeth Goodstein traces the modern discourse on boredom through literary, philosophical, and sociological texts to fnd that as "a discursively articulated phenomenon...boredom is at once objective and subjective, emotion and intellectualization — not just a response to the modern world but also a historically constituted strategy for coping with its discontents." In both conceptions, boredom has to do fundamentally with an experience of time and problems of meaning.

Confdence has a common meaning of a certainty about handling something, such as work, family, social events, or relationships. Some have ascribed confdence as a state of being certain either that a hypothesis or prediction is correct or that a chosen course of action is the best or most eﬀective. Self-confdence is having confdence in one's self. Arrogance or hubris in this comparison is having unmerited confdence—believing something or someone is capable or correct when they are not. Overconfdence or presumptuousness is excessive belief in someone (or something) succeeding, without any regard for failure. Confdence can be a self-fulflling prophecy as those without it may fail or not try because they lack it and those with it may succeed because they have it rather than because of an innate ability. Taken to an extreme, over-confdence can cause problems as evidenced by the famous author Matthew Syed and mentioned here in this reference in regard to sport.

Contempt, not classifed among Paul Ekman's six basic emotions of anger, disgust, fear, happiness, sadness, and surprise, is a mixture of disgust and anger. Te word originated in 1393, from the Latin word contemptus meaning "scorn". It is the past participle of contemnere and from com- intensive prefx + temnere "to slight, scorn". Te origin is uncertain. Contemptuous appeared in 1529. Robert C. Solomon places contempt on the same continuum as resentment and anger, and he argues that the diﬀerences between the three are that resentment is anger directed toward a higher-status individual; anger is directed toward an equal- status individual; and contempt is anger directed toward a lower-status individual.

Contentment is a mental or emotional state of satisfaction maybe drawn from being at ease in one's situation, body and mind. Colloquially speaking, contentment could be a state of having accepted one's situation and is a milder and more tentative form of happiness. Contentment and the pursuit of contentment are possibly a central thread through many philosophical or religious schools across diverse cultures, times and geographies. Siddharta might have said "Health is the most precious gain and contentment the greatest wealth". John Stuart Mill, centuries later, would write "I have learned to seek my happiness by limiting my desires, rather than in attempting to satisfy them." Marcus Aurelius wrote "Live with the gods. And he who does so constantly shows them that his soul is satisfed with what is assigned to them." Hebrews 13:5 reads "Keep your lives free from the love of money and be content with what you have, because God has said, 'Never will I leave you; never will I forsake you.'" Chinese philosopher Zhuang Zhou once wrote in the 3rd century BCE (hypothetically)

67 "A gentleman who profoundly penetrates all things and is in harmony with their transformations will be contented with whatever time may bring. He follows the course of nature in whatever situation he may be.” Te literature seems to generally agree that contentment is maybe a state ideally reached through being happy with what a person has, as opposed to achieving one's larger ambitions, as Socrates described by probably saying "He who is not contented with what he has, would not be contented with what he would like to have." Tat said, there may be a number of elements of achievement that may make fnding a state of personal contentment easier: a strong family unit, a strong local community, and satisfaction of life's basic needs as perhaps expressed in Maslow's hierarchy of needs. In general, the more needs in Maslow's hierarchy are achieved, the more easily one might achieve contentment.

Courage (also called bravery or valour) is the choice and willingness to confront agony, pain, danger, uncertainty, or intimidation. Physical courage is bravery in the face of physical pain, hardship, death or threat of death, while moral courage is the ability to act rightly in the face of popular opposition, shame, scandal, discouragement, or personal loss. Te classical virtue of fortitude (andreia, fortitudo) is also translated "courage", but includes the aspects of perseverance and patience. In the Western tradition, notable thoughts on courage have come from philosophers, Socrates, Plato, Aristotle, Aquinas, and Kierkegaard; in the Eastern tradition, some thoughts on courage were oﬀered by the Tao Te Ching. More recently, courage has been explored by the discipline of psychology.

Curiosity (from Latin cūriōsitās, from cūriōsus "careful, diligent, curious", akin to cura "care") is a quality related to inquisitive thinking such as exploration, investigation, and learning, evident by observation in humans and other animals. Curiosity is heavily associated with all aspects of human development, in which derives the process of learning and desire to acquire knowledge and skill.Te term curiosity can also be used to denote the behavior or emotion of being curious, in regard to the desire to gain knowledge or information. Curiosity as a behavior and emotion is attributed over millennia as the driving force behind not only human development, but developments in science, language, and industry.

Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behavior, feelings, and sense of well-being. A depressed mood is a normal temporary reaction to life events such as loss of a loved one. It is also a symptom of some physical diseases and a side effect of some drugs and medical treatments. Depressed mood is also a symptom of some mood disorders such as major depressive disorder or dysthymia. People with a depressed mood may be notably sad, anxious, or empty; they may also feel notably hopeless, helpless, dejected, or worthless. Other symptoms expressed may include senses of guilt, irritability, or anger. Further feelings expressed by these individuals may include feeling ashamed or an expressed restlessness. Tese individuals may notably lose interest in activities that they once considered pleasurable to family and friends or otherwise experience either a loss of appetite or overeating. Experiencing problems concentrating, remembering general facts or details, otherwise making decisions or experiencing relationship difficulties may also be notable factors in these individuals' depression and may also lead to their attempting or actually dying by suicide.

Expressed insomnia, excessive sleeping, fatigue, and vocalizing general aches, pains, and digestive problems and a reduced energy may also be present in individuals experiencing depression.

Desire is a sense of longing or hoping for a person, object, or outcome. Te same sense is expressed by emotions such as "craving". When a person desires something or someone, their sense of longing is excited by the enjoyment or the thought of the item or person, and they want to take actions to obtain their goal. Te motivational aspect of desire has long been noted by philosophers; Tomas Hobbes (1588–1679) asserted that human desire is the fundamental motivation of all human action. While desires are often classifed as emotions by laypersons, psychologists often describe desires as diﬀerent from emotions; psychologists tend to argue that desires arise from bodily structures, such as the stomach's need for food, whereas emotions arise from a person's mental state. Marketing and advertising companies have used psychological research on how desire is stimulated to fnd more eﬀective ways to induce consumers into buying a given product or service. While some advertising attempts to give buyers a sense of lack or wanting, other types of advertising create desire associating the product with desirable attributes, by showing either a celebrity or a model with the product. Te theme of desire is at the core of romance novels, which often create drama by showing cases where human desire is impeded by social conventions, class, or cultural barriers. Te theme of desire is also used in other literary genres, such as Gothic novels (e.g., Dracula by Bram Stoker, in which desire is mingled with fear and dread). Poets ranging from Homer to Toni Morrison have dealt with the theme of desire in their work. Just as desire is central to the written fction genre of romance, it is the central theme of melodrama flms, which use plots that appeal to the heightened emotions of the audience by showing "crises of human emotion, failed romance or friendship", in which desire is thwarted or unrequited.

Disappointment is the feeling of dissatisfaction that follows the failure of expectations or hopes to manifest. Similar to regret, it diﬀers in that a person who feels regret focuses primarily on the personal choices that contributed to a poor outcome, while a person feeling disappointment focuses on the outcome itself. It is a source of psychological stress. Te study of 68 disappointment—its causes, impact, and the degree to which individual decisions are motivated by a desire to avoid it —is a focus in the feld of decision analysis, as disappointment is, along with regret, one of two primary emotions involved in decision-making.

Disgust is an emotional response of revulsion to something considered oﬀensive, distasteful, or unpleasant. In Te Expression of the Emotions in Man and Animals, Charles Darwin wrote that disgust is a sensation that refers to something revolting. Disgust is experienced primarily in relation to the sense of taste (either perceived or imagined), and secondarily to anything which causes a similar feeling by sense of smell, touch, or vision. Musically sensitive people may even be disgusted by the cacophony of inharmonious sounds. Research continually has proven a relationship between disgust and anxiety disorders such as arachnophobia, blood-injection-injury type phobias, and contamination fear related obsessive–compulsive disorder (also known as OCD).

Disgust is one of the basic emotions of Robert Plutchik's theory of emotions and has been studied extensively by Paul Rozin. It invokes a characteristic facial expression, one of Paul Ekman's six universal facial expressions of emotion. Unlike the emotions of fear, anger, and sadness, disgust is associated with a decrease in heart rate. Distrust is a formal way of not trusting any one party too much in a situation of grave risk or deep doubt. It is commonly expressed in civics as a division or balance of powers, or in politics as means of validating treaty terms. Systems based on distrust simply divide the responsibility so that checks and balances can operate. Te phrase "Trust, but verify" refers specifcally to distrust. An electoral system or adversarial process inevitably is based on distrust, but not on mistrust. Parties compete in the system, but they do not compete to subvert the system itself, or gain bad faith advantage through it - if they do they are easily caught by the others. Much mistrust does exist between parties, and it is exactly this which motivates putting in place a formal system of distrust. Diplomatic protocol for instance, which applies between states, relies on such means as formal disapproval which in eﬀect say "we do not trust that person". It also tends to rely on a strict etiquette - distrusting each person's habits to signal their intent, and instead relying on a global standard for behaviour in sensitive social settings. A protocol as defned in computer science uses a more formal idea of distrust itself. Diﬀerent parts of a system are not supposed to "trust" each other but rather perform specifc assertions, requests and validations. Once these are passed, the responsibility for errors lies strictly with the receiving part of the system, not that which sent the original information. Applying this principle inside one program is called contract-based design. Corporate governance relies on distrust insofar as the board is not to trust the reports it receives from management, but is empowered to investigate them, challenge them, and otherwise act on behalf of shareholders vs. managers. Te fact that they rarely or never do so in most American companies is a sign that the distrust relationship has broken down - accounting scandals and calls for accounting reform are the inevitable result. It is precisely to avoid such larger crises of trust in "the system" that formal distrust measures are put in place to begin with.

Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to assent to any of them.[1][better source needed] Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty, distrust or lack of conviction on certain facts, actions, motives, or decisions. Doubt can result in delaying or rejecting relevant action out of concern for mistakes or missed opportunities.

Ecstasy (from Ancient Greek ἔκστασις ékstasis) is a subjective experience of total involvement of the subject, with an object of his or her awareness. In classical Greek literature it refers to removal of the mind or body "from its normal place of function.” Total involvement with an object of interest is not an ordinary experience because of being aware of other objects, thus ecstasy is an example of an altered state of consciousness characterized by diminished awareness of other objects or the total lack of the awareness of surroundings and everything around the object. Te word is also used to refer to any heightened state of consciousness or intensely pleasant experience. It is also used more specifcally to denote states of awareness of non-ordinary mental spaces, which may be perceived as spiritual (the latter type of ecstasy often takes the form of religious ecstasy).

Embarrassment is an emotional state that is associated with moderate to high levels of discomfort, and which is usually experienced when someone has a socially unacceptable or frowned-upon act or condition that was witnessed by or revealed to others. Usually some perception of loss of honor or dignity (or other high- value ideals) is involved, but the embarrassment level and the type depends on the situation. Embarrassment is similar to shame in some sense, except that shame may be experienced for an act known only to oneself. Also, embarrassment usually carries the connotation of being caused by an act that is merely socially unacceptable, rather than morally wrong.

Empathy is the capacity to understand or feel what another person is experiencing from within the other person's frame of reference, i.e., the capacity to place oneself in another's position. Tere are many defnitions for empathy that encompass a broad range of emotional states. Types of empathy include cognitive empathy, emotional empathy, and somatic empathy.

Enthusiasm is intense enjoyment, interest, or approval. Te word was originally used to refer to a person possessed by a god, or someone who exhibited intense piety. Te word originates from the Greek ἐνθουσιασμός from ἐν and θεός and 69 οὐσία, meaning "possessed by god's essence", applied by the Greeks to manifestations of divine possession, by Apollo (as in the case of the Pythia), or by Dionysus (as in the case of the Bacchantes and Maenads), the term enthusiasm was also used in a transferred or fgurative sense. Socrates taught that the inspiration of poets is a form of enthusiasm. Te term was confned to a belief in religious inspiration, or to intense religious fervour or emotion. Francis of Assisi in Ecstasy by Caravaggio, 1594 From this, a Syrian sect of the 4th century was known as the Enthusiasts. Tey believed that "by perpetual prayer, ascetic practices and contemplation, man could become inspired by the Holy Spirit, in spite of the ruling evil spirit, which the fall had given to him". From their belief in the eﬃcacy of prayer, they were also known as Euchites. Several Protestant sects of the 16th and 17th centuries were called enthusiastic. During the years that immediately followed the Glorious Revolution, "enthusiasm" was a British pejorative term for advocacy of any political or religious cause in public, i.e. fanaticism. Such "enthusiasm" was seen in the time around 1700 as the cause of the previous century's English Civil War and its attendant atrocities, and thus it was an absolute social sin to remind others of the war by engaging in enthusiasm. Te Royal Society bylaws stipulated that any person discussing religion or politics at a Society meeting was to be summarily ejected for being an "enthusiast." During the 18th century, popular Methodists such as John Wesley or George Whitefeld were accused of blind enthusiasm, a charge against which they defended themselves by distinguishing fanaticism from "religion of the heart." Enthusiasm can be clearly seen in the modern day - displayed by characters like Dr George Cheetham and Captain Edward Larmour.

Envy (from Latin invidia) is an emotion which "occurs when a person lacks another's superior quality, achievement, or possession and either desires it or wishes that the other lacked it”. Bertrand Russell said that envy was one of the most potent causes of unhappiness. Not only is the envious person rendered unhappy by his or her envy, Russell explained, but that person also wishes to infict misfortune on others. Although envy is generally seen as something negative, Russell also believed that envy was a driving force behind the movement towards democracy and must be endured to achieve a more just social system. However, psychologists have recently suggested that there may be two types of envy: malicious envy and benign envy—malicious envy being proposed as a sick force that ruins a person and his/her mind and causes the envious person to blindly want the "hero" to suﬀer; on the other hand, benign envy being proposed as a type of positive motivational force that causes the person to aspire to be as good as the "hero"—but only if benign envy is used in a right way. Envy and gloating have parallel structures as emotions.

Euphoria ( /juːˈfɔːriə/ is an aﬀective state in which a person experiences pleasure or excitement and intense feelings of well- being and happiness. Certain ailments, many of which are addictive, can cause euphoria, which at least partially motivates their recreational use. Similarly, certain natural rewards and social activities, such as aerobic exercise, laughter, listening to emotionally arousing music, music-making, and dancing, can induce a state of euphoria. Euphoria is also a symptom of certain neurological or neuropsychiatric disorders, such as mania. Romantic love and components of the human sexual response cycle are also associated with the induction of euphoria. According to Kent Berridge, an aﬀective neuroscientist, intense euphoria occurs from the simultaneous activation of every hedonic hotspot within the brain's reward system.

Fear is a feeling induced by perceived danger or threat that occurs in certain types of organisms, which causes a change in metabolic and organ functions and ultimately a change in behavior, such as feeing, hiding, or freezing from perceived traumatic events. Fear in human beings may occur in response to a specifc stimulus occurring in the present, or in anticipation or expectation of a future threat perceived as a risk to body or life. Te fear response arises from the perception of danger leading to confrontation with or escape from/avoiding the threat (also known as the fght-or-fight response), which in extreme cases of fear (horror and terror) can be a freeze response or paralysis. In humans and animals, fear is modulated by the process of cognition and learning. Tus fear is judged as rational or appropriate and irrational or inappropriate. An irrational fear is called a phobia.

Psychologists such as John B. Watson, Robert Plutchik, and Paul Ekman have suggested that there is only a small set of basic or innate emotions and that fear is one of them. Tis hypothesized set includes such emotions as acute stress reaction, anger, angst, anxiety, fright, horror, joy, panic, and sadness. Fear is closely related to, but should be distinguished from, the emotion anxiety, which occurs as the result of threats that are perceived to be uncontrollable or unavoidable.Te fear response serves survival by generating appropriate behavioral responses, so it has been preserved throughout evolution.

In psychology, frustration is a common emotional response to opposition. Related to anger, annoyance and disappointment, frustration arises from the perceived resistance to the fulfllment of an individual's will or goal and is likely to increase when a will or goal is denied or blocked. Tere are two types of frustration; internal and external. Internal frustration may arise from challenges in fulflling personal goals, desires, instinctual drives and needs, or dealing with perceived defciencies, such as a lack of confdence or fear of social situations. Confict, such as when one has competing goals that interfere with one another, can also be an internal source of frustration and can create cognitive dissonance. External causes of frustration involve conditions outside an individual's control, such as a physical roadblock, a difficult task, or the perception of wasting time. Tere are multiple ways individuals cope with frustration such as passive–aggressive behavior, anger, or violence, 70 although frustration may also propel positive processes via enhanced effort and strive. Tis broad range of potential outcomes makes it difficult to identify the original cause(s) of frustration, as the responses may be indirect. However, a more direct and common response is a propensity towards aggression.

Gratitude, thankfulness, thanksgiving, or gratefulness, from the Latin gratus ‘pleasing, thankful’, is a feeling of appreciation felt by and/or similar positive response shown by the recipient of kindness, gifts, help, favors, or other types of generosity, towards the giver of such gifts. Te experience of gratitude has historically been a focus of several world religions. It has also been a topic of interest to ancient, medieval and modern philosophers, and continues to engage contemporary western philosophers. Te systematic study of gratitude within psychology only began around the year 2000, possibly because psychology traditionally focused more on understanding distress than on understanding positive emotions. Te study of gratitude within psychology has focused on the understanding of the short term experience of the emotion of gratitude (state gratitude), individual diﬀerences in how frequently people feel gratitude (trait gratitude), and the relationship between these two aspects.

Grief is a multifaceted response to loss, particularly to the loss of someone or something that has died, to which a bond or aﬀection was formed. Although conventionally focused on the emotional response to loss, it also has physical, cognitive, behavioral, social, cultural, spiritual and philosophical dimensions. While the terms are often used interchangeably, bereavement refers to the state of loss, and grief is the reaction to that loss. Grief is a natural response to loss. It is the emotional suﬀering one feels when something or someone the individual loves is taken away. Te grief associated with death is familiar to most people, but individuals grieve in connection with a variety of losses throughout their lives, such as unemployment, ill health or the end of a relationship. Loss can be categorized as either physical or abstract, the physical loss being related to something that the individual can touch or measure, such as losing a spouse through death, while other types of loss are abstract, and relate to aspects of a person’s social interactions.

Guilt is a cognitive or an emotional experience that occurs when a person believes or realizes—accurately or not—that he or she has compromised his or her own standards of conduct or has violated a universal moral standard and bears signifcant responsibility for that violation. Guilt is closely related to the concept of remorse.

In philosophy, happiness is translated from the Greek concept of eudaimonia, and refers to the good life, or fourishing, as opposed to an emotion. In psychology, happiness is a mental or emotional state of well-being which can be defned by, among others, positive or pleasant emotions ranging from contentment to intense joy. Happy mental states may refect judgements by a person about their overall well-being. Since the 1960s, happiness research has been conducted in a wide variety of scientifc disciplines, including gerontology, social psychology, clinical and medical research and happiness economics.

Hatred or hate is a deep and extreme emotional dislike, especially invoking feelings of anger or resentment. It can be directed against individuals, groups, entities, objects, behaviors, or ideas. Hatred is often associated with feelings of anger, disgust and a disposition towards hostility.

Hope is an optimistic state of mind that is based on an expectation of positive outcomes with respect to events and circumstances in one's life or the world at large. As a verb, its defnitions include: "expect with confdence" and "to cherish a desire with anticipation”. Among its opposites are dejection, hopelessness and despair.

Te distinction between horror and terror is a standard literary and psychological concept applied especially to Gothic and horror fction. Terror is usually described as the feeling of dread and anticipation that precedes the horrifying experience. By contrast, horror is the feeling of revulsion that usually follows a frightening sight, sound, or otherwise experience. It is the feeling one gets after coming to an awful realization or experiencing a deeply unpleasant occurrence. In other words, horror is more related to being shocked or scared (being horrifed), while terror is more related to being anxious or fearful. Horror has also been defned as a combination of terror and revulsion. Te distinction between terror and horror was frst characterized by the Gothic writer Ann Radcliffe (1764– 1823). Terror is characterized by "obscurity" or indeterminacy in its treatment of potentially horrible events; it is this indeterminacy which leads to the sublime. She says in the essay that it "expands the soul and awakens the faculties to a high degree of life". Horror, in contrast, "freezes and nearly annihilates them" with its unambiguous displays of atrocity. She goes on: "I apprehend that neither Shakespeare nor Milton by their fctions, nor Mr Burke by his reasoning, anywhere looked to positive horror as a source of the sublime, though they all agree that terror is a very high one; and where lies the great difference between horror and terror, but in uncertainty and obscurity, that accompany the frst, respecting the dreader evil.” According to Devendra Varma in Te Gothic Flame (1966): Te difference between Terror and Horror is the difference between awful apprehension and sickening realization: between the smell of death and stumbling against a corpse. Horror is also a genre of flm and fction that relies on horrifying images or situations to tell stories and prompt reactions in their audiences. In these flms the moment of horrifying revelation is usually preceded by a terrifying build up, often using the medium of scary music. In his non-fction book Danse Macabre, Stephen

71 King elaborated on the themes of terror and horror, also adding a third element which he referred to as "revulsion". He describes terror as "the fnest element" of the three, and the one he strives hardest to maintain in his own writing. Citing many examples, he defnes "terror" as the suspenseful moment in horror before the actual monster is revealed. "Horror," King writes, is that moment at which one sees the creature/aberration that causes the terror or suspense, a "shock value". King fnally compares "revulsion" with the gag-refex, a bottom-level, cheap gimmick which he admits he often resorts to in his own fction if necessary, confessing: "I recognize terror as the fnest emotion and so I will try to terrorize the reader. But if I fnd that I cannot terrify, I will try to horrify, and if I fnd that I cannot horrify, I'll go for the gross-out. I'm not proud.” One may experience horror in many situations such as when they almost get ran over by a semi truck or are shown a picture of werewolf tigers...

Hostility is seen as form of emotionally charged aggressive behavior. In everyday speech it is more commonly used as a synonym for anger and aggression. It appears in several psychological theories. For instance it is a facet of neuroticism in the NEO PI, and forms part of personal construct psychology, developed by George Kelly.

Humiliation is the abasement of pride, which creates mortifcation or leads to a state of being humbled or reduced to lowliness or submission. It is an emotion felt by a person whose social status, either by force or willingly, has just decreased. It can be brought about through intimidation, physical or mental mistreatment or trickery, or by embarrassment if a person is revealed to have committed a socially or legally unacceptable act. Whereas humility can be sought alone as a means to de- emphasize the ego, humiliation must involve other person(s), though not necessarily directly or willingly. Humiliation is currently an active research topic, and is now seen as an important – and complex – core dynamic in human relationships, having implications at intrapersonal, interpersonal, institutional and international levels.

Interest is a feeling or emotion that causes attention to focus on an object, event, or process. In contemporary psychology of interest, the term is used as a general concept that may encompass other more specifc psychological terms, such as curiosity and to a much lesser degree surprise. Te emotion of interest does have its own facial expression, of which the most prominent component is having dilated pupils.

Jealousy is an emotion; the term generally refers to the thoughts or feelings of insecurity, fear, concern, and envy over relative lack of possessions, status or something of great personal value, particularly in reference to a comparator. Jealousy often consists of one or more of emotions such as anger, resentment, inadequacy, helplessness or disgust. In its original meaning, jealousy is distinct from envy, though the two terms have popularly become synonymous in the English language, with jealousy now also taking on the defnition originally used for envy alone. Jealousy is a typical experience in human relationships, and it has been observed in infants as young as fve months. Some claim that jealousy is seen in every culture; however, others claim jealousy is a culture-specifc phenomenon. Jealousy can either be suspicious or reactive, and it is often reinforced as a series of particularly strong emotions and constructed as a universal human experience. Psychologists have proposed several models to study the processes underlying jealousy and have identifed factors that result in jealousy. Sociologists have demonstrated that cultural beliefs and values play an important role in determining what triggers jealousy and what constitutes socially acceptable expressions of jealousy. Biologists have identifed factors that may unconsciously infuence the expression of jealousy. Troughout history, artists have also explored the theme of jealousy in photographs, paintings, flms, songs, plays, poems, and books, and theologians have oﬀered religious views of jealousy based on the scriptures of their respective faiths.

Te word joy means a feeling of great pleasure and happiness. C. S. Lewis saw clear distinction between joy and pleasure and happiness; "I sometimes wonder whether all pleasures are not substitutes for Joy.", and "I call it Joy, which is here a technical term and must be sharply distinguished both from Happiness and Pleasure. Joy (in my sense) has indeed one characteristic, and one only, in common with them; the fact that anyone who has experienced it will want it again... I doubt whether anyone who has tasted it would ever, if both were in his power, exchange it for all the pleasures in the world. But then Joy is never in our power and Pleasure often is.” Te causes of joy have been ascribed to various sources. “When the mind is pure, joy follows like a shadow that never leaves.” Gautama Buddha, "[Joy is] the emotional dimension of the good life, of a life that is both going well and is being lived well."Miroslav Volf, "Tis is the true joy in life, the being used for a purpose recognized by yourself as a mighty one; the being thoroughly worn out before you are thrown on the scrap heap; the being a force of Nature instead of a feverish selfsh little clod of ailments and grievances complaining that the world will not devote itself to making you happy." George Bernard Shaw and “Find a place inside where there's joy, and the joy will burn out the pain.” Joseph Campbell.

Loneliness is a complex and usually unpleasant emotional response to isolation. Loneliness typically includes anxious feelings about a lack of connection or communication with other beings, both in the present and extending into the future. As such, loneliness can be felt even when surrounded by other people. Te causes of loneliness are varied and include social, mental, emotional and physical factors. Research has shown that loneliness is prevalent throughout society, including people in marriages, relationships, families, veterans, and those with successful careers. It has been a long explored theme in the

72 literature of human beings since classical antiquity. Loneliness has also been described as social pain—a psychological mechanism meant to motivate an individual to seek social connections. Loneliness is often defned in terms of one's connectedness to others, or more specifcally as "the unpleasant experience that occurs when a person's network of social relations is defcient in some important way”.

Love encompasses a variety of different emotional and mental states, typically strongly and positively experienced, ranging from the deepest interpersonal affection to the simplest pleasure. An example of this range of meanings is that the love of a mother differs from the love of a spouse differs from the love of food. Most commonly, love refers to a feeling of strong attraction and emotional attachment. Love can also be a virtue representing human kindness, compassion, and affection —"the unselfsh loyal and benevolent concern for the good of another". It may also describe compassionate and affectionate actions towards other humans, one's self or animals. Ancient Greek philosophers identifed four forms of love: essentially, familial love (in Greek, storge), friendly love (philia), romantic love (eros), and divine love (agape). Modern authors have distinguished further varieties of love: infatuated love, self-love, and courtly love. Non-Western traditions have also distinguished variants or symbioses of these states. Love has additional religious or spiritual meaning. Tis diversity of uses and meanings combined with the complexity of the feelings involved makes love unusually difficult to consistently defne, compared to other emotional states. Love in its various forms acts as a major facilitator of interpersonal relationships and, owing to its central psychological importance, is one of the most common themes in the creative arts. Love may be understood as a function to keep human beings together against menaces and to facilitate the continuation of the species.

Lust is a strong emotion or feeling. Te lust can take any form such as the lust for sexuality, lust for expensive objects (extravagance) or the lust for power. It can take such mundane forms as the lust for food as distinct from the need for food. Lust is a psychological force producing intense wanting for an object, or circumstance fulflling the emotion.

Outrage is a strong emotion characterized by a combiantion of surprise, anger and disgust,or and anger. usually in reaction to a grave personal oﬀense. It comes from old French and meant "beyond rage”. Moral outrage is the emotion of outrage experienced in reaction to an injustice, as such involving a moral judgement. It is a requirement for genuine moral outrage (as opposed to merely personal outrage or feelings of tribal loyalty) that it must be caused independent of whether the injustice is perpetrated against oneself, against a member of one's ingroup, against a stranger, or against the outgroup.

Panic is a sudden sensation of fear, which is so strong as to dominate or prevent reason and logical thinking, replacing it with overwhelming feelings of anxiety and frantic agitation consistent with an animalistic fght-or-fight reaction. Panic may occur singularly in individuals or manifest suddenly in large groups as mass panic (closely related to herd behavior).

Passion (Greek πασχω and late Latin (Christian theology) pati: "suﬀer") is a feeling of intense enthusiasm towards or compelling desire for someone or something. Passion can range from eager interest in or admiration for an idea, proposal, or cause; to enthusiastic enjoyment of an interest or activity; to strong attraction, excitement, or emotion towards a person. It is particularly used in the context of romance or sexual desire, though it generally implies a deeper or more encompassing emotion than that implied by the term lust. Denis Diderot describes passions as "penchants, inclinations, desires and aversions carried to a certain degree of intensity, combined with an indistinct sensation of pleasure or pain, occasioned or accompanied by some irregular movement of the blood and animal spirits, are what we call passions. Tey can be so strong as to inhibit all practice of personal freedom, a state in which the soul is in some sense rendered passive; whence the name passions. Tis inclination or so-called disposition of the soul, is born of the opinion we hold that a great good or a great evil is contained in an object which in and of itself arouses passion”.

Pity is a sympathetic sorrow evoked by the suﬀering of others and is used in a comparable sense to compassion, condolence or empathy. Trough frequent, insincere, pejorative usage, it is used to connote feelings of superiority, condescension, or contempt.

Pleasure is a broad class of mental states that humans and other animals experience as positive, enjoyable, or worth seeking. It includes more specifc mental states such as happiness, entertainment, enjoyment, ecstasy, and euphoria. Te early psychological concept of pleasure, the pleasure principle, describes it as a positive feedback mechanism, motivating the organism to recreate in the future the situation which it has just found pleasurable and to avoid situations that have caused pain in the past. Te experience of pleasure is subjective and diﬀerent individuals will experience diﬀerent kinds and amounts of pleasure in the same situation. Many pleasurable experiences are associated with satisfying basic biological drives, such as eating, exercise, hygiene, and sex. Te appreciation of cultural artifacts and activities such as art, music, dancing, and literature is often pleasurable. Based upon the incentive salience model of reward – the attractive and motivational property of a stimulus that induces approach behavior and consummatory behavior– an intrinsic reward has two components: a "wanting" or desire component which is refected in approach behavior and a "liking" or pleasure component that is refected in consummatory behavior. While all pleasurable stimuli are rewards, some rewards do not evoke pleasure.

73 Pride is an inwardly directed emotion that carries two antithetical meanings. With a negative connotation pride refers to a foolishly and irrationally corrupt sense of one's personal value, status or accomplishments, used synonymously with hubris. With a positive connotation, pride refers to a humble and content sense of attachment toward one's own or another's choices and actions, or toward a whole group of people, and is a product of praise, independent self-refection, and a fulflled feeling of belonging. In Judaism, pride is called the root of all evil. In Christianity, pride is the original and most serious of the seven deadly sins, the father of all sins.

Philosophers and social psychologists have noted that pride is a complex secondary emotion which requires the development of a sense of self and the mastery of relevant conceptual distinctions (e.g. that pride is distinct from happiness and joy) through language-based interaction with others. Some social psychologists identify the nonverbal expression of pride as a means of sending a functional, automatically perceived signal of high social status. In contrast, pride could also be defned as a lowly disagreement with the truth. One defnition of pride in the former sense comes from St. Augustine: "the love of one's own excellence".A similar defnition comes from Meher Baba: "Pride is the specifc feeling through which egoism manifests.” Pride is sometimes viewed as corrupt or as a vice, sometimes as proper or as a virtue. While some philosophers such as Aristotle (and George Bernard Shaw) consider pride (but not hubris) a profound virtue, some world religions consider pride's fraudulent form a sin, such as is expressed in Proverbs 11:2 of the Hebrew Bible. When viewed as a virtue, pride in one's abilities is known as virtuous pride, greatness of soul or magnanimity, but when viewed as a vice it is often known to be self-idolatry, sadistic contempt, vanity or vainglory. Pride can also manifest itself as a high opinion of one's nation (national pride) and ethnicity (ethnic pride).

Rage (often called fury or frenzy) is a feeling of intense, violent, or growing anger. It is sometimes associated with the fght- or-fight response, and is often activated in response to being in the presence of a threat. Te phrase "thrown into a ft of rage" expresses the immediate nature of rage that occurs from extended exposure to a threat. If left unchecked, rage may lead to violence against the threat.

Regret is a negative conscious and emotional reaction to one's personal decision-making, a choice resulting in action or inaction. Regret is related to perceived opportunity. Its intensity varies over time after the decision, in regard to action versus action, and in regard to self-control at a particular age. Te self- recrimination which comes with regret is thought to spur corrective action and adaptation. In Western societies adults have the highest regrets regarding choices of their education.

Remorse is an emotional expression of personal regret felt by a person after they have committed an act which they deem to be shameful, hurtful, or violent. Remorse is closely allied to guilt and self-directed resentment. When a person regrets an earlier action or failure to act, it may be because of remorse or in response to various other consequences, including being punished for the act or omission. In a legal context, the perceived remorse of an oﬀender is assessed by Western justice systems during trials, sentencing, parole hearings, and in restorative justice. However, it has been pointed out that epistemological problems arise in assessing an oﬀender's level of remorse. A person who is incapable of feeling remorse is often diagnosed with antisocial personality disorder - as characterized in the DSM IV-TR. In general, a person needs to be unable to feel fear, as well as remorse, in order to develop psychopathic traits. Legal and business professions such as insurance have done research on the expression of remorse via apologies, primarily because of the potential litigation and fnancial implications.

Resentment (also called ranklement or bitterness) is a mixture of disappointment, anger, and fear. It comprises the three basic emotions of disgust, sadness and surprise—the perception of injustice. As the surprise of injustice becomes less frequent, so too fades anger and fear, leaving disappointment as the predominant emotion. So, to the extent perceived disgust and sadness remain, the level of disappointment also remains. Resentment can be triggered by an emotionally disturbing experience felt again or relived in the mind. When the person feeling resentment is directing the emotion at himself or herself, it appears as remorse. Robert C. Solomon, a professor of philosophy at the University of Texas at Austin, places resentment on the same continuum as anger and contempt, and he argues that the diﬀerences between the three are that resentment is anger directed toward a higher-status individual; anger is directed toward an equal-status individual; and contempt is anger directed toward a lower-status individual. Resentment is the foundation of hatred. It is not one of Paul Ekman's six basic emotions (surprise, disgust, happiness, sadness, anger, and fear). Te word originates from French "ressentir", re-, intensive prefx, and sentir "to feel"; from the Latin "sentire". Te English word has become synonymous with anger and spite.

Sadness is an emotional pain associated with, or characterized by, feelings of disadvantage, loss, despair, grief, helplessness, disappointment and sorrow. An individual experiencing sadness may become quiet or lethargic, and withdraw themselves from others. An example of severe sadness is depression. Crying can be an indication of sadness. Sadness is one of the "six basic emotions" described by Paul Ekman, along with happiness, anger, surprise, fear, and disgust.

74 Saudade (European Portuguese: [sɐwˈðaðɨ], Brazilian Portuguese: [sawˈdadi] or [sawˈdadʒi], Galician: [sawˈðaðe]; plural saudades) is a deep emotional state of nostalgic or profound melancholic longing for an absent something or someone that one loves. Moreover, it often carries a repressed knowledge that the object of longing might never return. One English translation of the word is missingness, although it might not convey the feeling of deep emotion attached to the word "saudade". Stronger forms of saudade might be felt towards people and things whose whereabouts are unknown, such as a lost lover, or a family member who has gone missing, moved away, separated, or died. Saudade was once described as "the love that remains" after someone is gone. Saudade is the recollection of feelings, experiences, places, or events that once brought excitement, pleasure, well-being, which now triggers the senses and makes one live again. It can be described as an emptiness, like someone (e.g., one's children, parents, sibling, grandparents, friends, pets) or something (e.g., places, things one used to do in childhood, or other activities performed in the past) that should be there in a particular moment is missing, and the individual feels this absence. It brings sad and happy feelings altogether, sadness for missing and happiness for having experienced the feeling.

Schadenfreude (/ˈʃɑːdənfrɔɪdə/; German: [ˈʃaːdn̩ˌfʁɔʏd̯ ə]; lit. 'harm-joy') is the experience of pleasure, joy, or self- satisfaction that comes from learning of or witnessing the troubles, failures, or humiliation of another.

Te concept of self-confdence is commonly used as self-assurance in one's personal judgment, ability, power, etc. One increases self-confdence from experiences of having mastered particular activities. It is a positive belief that in the future one can generally accomplish what one wishes to do. Self-confdence is not the same as self-esteem, which is an evaluation of one’s own worth, whereas self-confdence is more specifcally trust in one’s ability to achieve some goal, which one meta- analysis suggested is similar to generalization of self-efficacy. Abraham Maslow and many others after him have emphasized the need to distinguish between self-confdence as a generalized personality characteristic, and self-confdence with respect to a specifc task, ability or challenge (i.e. self-efficacy). Self-confdence typically refers to general self-confdence. Tis is different from self-efficacy, which psychologist Albert Bandura has defned as a “belief in one’s ability to succeed in specifc situations or accomplish a task and therefore is the term that more accurately refers to specifc self-confdence. Psychologists have long noted that a person can possess self-confdence that he or she can complete a specifc task (self-efficacy) (e.g. cook a good meal or write a good novel) even though they may lack general self-confdence, or conversely be self-confdent though they lack the self-efficacy to achieve a particular task (e.g. write a novel). Tese two types of self-confdence are, however, correlated with each other, and for this reason can be easily confated.

Shame is a painful, social emotion that can be seen as resulting "...from comparison of the self's action with the self's standards...". but which may equally stem from comparison of the self's state of being with the ideal social context's standard. Tus, shame may stem from volitional action or simply self-regard; no action by the shamed being is required: simply existing is enough. Both the comparison and standards are enabled by socialization. Tough usually considered an emotion, shame may also variously be considered an affect, cognition, state, or condition. Te roots of the word shame are thought to derive from an older word meaning "to cover"; as such, covering oneself, literally or fguratively, is a natural expression of shame. Nineteenth-century scientist Charles Darwin, in his book Te Expression of the Emotions in Man and Animals, described shame affect as consisting of blushing, confusion of mind, downward cast eyes, slack posture, and lowered head, and he noted observations of shame affect in human populations worldwide. He also noted the sense of warmth or heat (associated with the vasodilation of the face and skin) occurring in intense shame. Shame can also result in crying. A "sense of shame" is the feeling known as guilt but "consciousness" or awareness of "shame as a state" or condition defnes core/toxic shame (Lewis, 1971; Tangney, 1998). Te key emotion in all forms of shame is contempt (Miller, 1984; Tomkins, 1967). Two realms in which shame is expressed are the consciousness of self as bad and self as inadequate. People employ negative coping responses to counter deep rooted, associated sense of "shameworthiness". Te shame cognition may occur as a result of the experience of shame affect or, more generally, in any situation of embarrassment, dishonor, disgrace, inadequacy, humiliation, or chagrin. A "state of shame" is assigned internally from being a victim of environment where the sense of self is stigmatized like being denigrated by caregivers, overtly rejected by parents in favor of siblings needs, etc. and the same is assigned externally, by others, regardless of one's own experience or awareness. "To shame" generally means to actively assign or communicate a state of shame to another. Behaviors designed to "uncover" or "expose" others are sometimes used for this purpose, as are utterances like "Shame!" or "Shame on you!" Finally, to "have shame" means to maintain a sense of restraint against offending others (as with modesty, humility, and deference) while to "have no shame" is to behave without such restraint (as with excessive pride or hubris).

Shock -Acute stress reaction (also called acute stress disorder, psychological shock, mental shock, or simply shock) is a psychological condition arising in response to a terrifying or traumatic event, or witnessing a traumatic event that induces a strong emotional response within the individual. It should not be confused with the unrelated circulatory condition of shock/hypoperfusion. Acute stress reaction (ASR) may develop into delayed stress reaction (better known as PTSD) if stress is not correctly managed. ASR is characterized by re-living and avoiding reminders of an aversive event, as well as generalized hypervigilance after initial exposure to a traumatic event. ASD is differentiated from PTSD as a disorder that precedes it, and if symptoms last for more than one month, it will develop into PTSD. It can thus be thought of as the acute phase of PTSD. 75 Shyness (also called diffidence) is the feeling of apprehension, lack of comfort, or awkwardness especially when a person is around other people. Tis commonly occurs in new situations or with unfamiliar people. Shyness can be a characteristic of people who have low self-esteem. Stronger forms of shyness are usually referred to as social anxiety or social phobia. Te primary defning characteristic of shyness is a largely ego-driven fear of what other people will think of a person's behavior. Tis results in a person becoming scared of doing or saying what they want to out of fear of negative reactions, being laughed at, humiliated or patronised, criticism or rejection. A shy person may simply opt to avoid social situations instead. One important aspect of shyness is social skills development. Schools and parents may implicitly assume children are fully capable of effective social interaction. Social skills training is not given any priority (unlike reading and writing) and as a result, shy students are not given an opportunity to develop their ability to participate in class and interact with peers. Teachers can model social skills and ask questions in a less direct and intimidating manner in order to gently encourage shy students to speak up in class, and make friends with other children.

Sorrow is an emotion, feeling, or sentiment. Sorrow "is more 'intense' than sadness... it implies a long-term state". At the same time "sorrow — but not unhappiness — suggests a degree of resignation... which lends sorrow its peculiar air of dignity”. Moreover, "in terms of attitude, sorrow can be said to be half way between sadness (accepting) and distress (not accepting)”

Suffering, or pain in a broad sense, may be an experience of unpleasantness and aversion associated with the perception of harm or threat of harm in an individual. Suffering is the basic element that makes up the negative valence of affective phenomena. Te opposite of suffering is pleasure or happiness. Suffering is often categorized as physical or mental. It may come in all degrees of intensity, from mild to intolerable. Factors of duration and frequency of occurrence usually compound that of intensity. Attitudes toward suffering may vary widely, in the sufferer or other people, according to how much it is regarded as avoidable or unavoidable, useful or useless, deserved or undeserved. Suffering occurs in the lives of sentient beings in numerous manners, often dramatically. As a result, many felds of human activity are concerned with some aspects of suffering. Tese aspects may include the nature of suffering, its processes, its origin and causes, its meaning and signifcance, its related personal, social, and cultural behaviors, its remedies, management, and uses.

Surprise (About this sound pronunciation (help·info)) is a brief mental and physiological state, a startle response experienced by animals and humans as the result of an unexpected event. Surprise can have any valence; that is, it can be neutral/ moderate, pleasant, unpleasant, positive, or negative. Surprise can occur in varying levels of intensity ranging from very- surprised, which may induce the fght-or-fight response, or little-surprise that elicits a less intense response to the stimuli.

Toleration is the acceptance of an action, object, or person which one dislikes or disagrees with, where one is in a position to disallow it but chooses not to. It has also been defned as "to bear or endure" or "to nourish, sustain or preserve" or as "a fair, objective, and permissive attitude toward those whose opinions, beliefs, practices, racial or ethnic origins, etc., diﬀer from one's own; freedom from bigotry" too. Toleration may signify "no more than forbearance and the permission given by the adherents of a dominant religion for other religions to exist, even though the latter are looked on with disapproval as inferior, mistaken, or harmful."

Tere is only one verb to tolerate and one adjective tolerant, but the two nouns tolerance and toleration have evolved slightly diﬀerent meanings. Tolerance is a state of mind that implies non-judgmental acceptance of diﬀerent lifestyles or beliefs, whereas toleration indicates the act of putting up with something that one disapproves of.

Historically, most incidents and writings pertaining to toleration involve the status of minority and dissenting viewpoints in relation to a dominant state religion. In the twentieth century and after, analysis of the doctrine of toleration has been expanded to include political and ethnic groups, LGBT individuals and other minorities, and human rights embodies the principle of legally enforced toleration.

In a social context, trust has several connotations. Defnitions of trust typically refer to a situation characterized by the following aspects: One party (trustor) is willing to rely on the actions of another party (trustee); the situation is directed to the future. In addition, the trustor (voluntarily or forcedly) abandons control over the actions performed by the trustee. As a consequence, the trustor is uncertain about the outcome of the other's actions; they can only develop and evaluate expectations. Te uncertainty involves the risk of failure or harm to the trustor if the trustee will not behave as desired. Vladimir Ilych Lenin expressed this idea with the sentence "Trust is good, control is better”. Trust can be attributed to relationships between people. It can be demonstrated that humans have a natural disposition to trust and to judge trustworthiness that can be traced to the neurobiological structure and activity of a human brain. Some studies indicate that trust can be altered e.g. by the application of oxytocin. When it comes to the relationship between people and technology, the attribution of trust is a matter of dispute. Te intentional stance demonstrates that trust can be validly attributed to human relationships with complex technologies. However, rational refection leads to the rejection of an ability to trust technological artefacts. One of the key current challenges in the social sciences is to re-think how the rapid progress of

76 technology has impacted constructs such as trust. Tis is specifcally true for information technology that dramatically alters causation in social systems. In the social sciences, the subtleties of trust are a subject of ongoing research. In sociology and psychology the degree to which one party trusts another is a measure of belief in the honesty, fairness, or benevolence of another party. Te term "confdence" is more appropriate for a belief in the competence of the other party. A failure in trust may be forgiven more easily if it is interpreted as a failure of competence rather than a lack of benevolence or honesty. In economics, trust is often conceptualized as reliability in transactions. In all cases trust is a heuristic decision rule, allowing the human to deal with complexities that would require unrealistic eﬀort in rational reasoning.

Wonder is an emotion comparable to surprise that people feel when perceiving something very rare or unexpected (but not threatening). It has historically been seen as an important aspect of human nature, specifcally being linked with curiosity and the drive behind intellectual exploration.Wonder is also often compared to the emotion of awe but awe implies fear or respect rather than joy.

Worry refers to the thoughts, images, and emotions of a negative nature in a repetitive, uncontrollable manner that results from a proactive cognitive risk analysis made to avoid or solve anticipated potential threats and their potential consequences. Worry is described as a response to a moderate challenge for when the subject has inadequate skills. Worry turns to be problematic if one has been excessively apprehensive over a lengthy period.

Perception (from the Latin perceptio) is the organization, identifcation, and interpretation of sensory information in order to represent and understand the presented information, or the environment.

All perception involves signals that go through the nervous system, which in turn result from physical or chemical stimulation of the sensory system. For example, vision involves light striking the retina of the eye, smell is mediated by odor molecules, and hearing involves pressure waves.

Perception is not only the passive receipt of these signals, but it's also shaped by the recipient's learning, memory, expectation, and attention.

Perception can be split into two processes, (1) processing the sensory input, which transforms these low-level information to higher-level information (e.g., extracts shapes for object recognition), (2) processing which is connected with a person's concepts and expectations (or knowledge), restorative and selective mechanisms (such as attention) that infuence perception.

Perception depends on complex functions of the nervous system, but subjectively seems mostly eﬀortless because this processing happens outside conscious awareness.

Since the rise of experimental psychology in the 19th Century, psychology's understanding of perception has progressed by combining a variety of techniques. Psychophysics quantitatively describes the relationships between the physical qualities of the sensory input and perception. Sensory neuroscience studies the brain mechanisms underlying perception. Perceptual systems can also be studied computationally, in terms of the information they process. Perceptual issues in philosophy include the extent to which sensory qualities such as sound, smell or color exist in objective reality rather than in the mind of the perceiver.

Although the senses were traditionally viewed as passive receptors, the study of illusions and ambiguous images has demonstrated that the brain's perceptual systems actively and pre-consciously attempt to make sense of their input. Tere is still active debate about the extent to which perception is an active process of hypothesis testing, analogous to science, or whether realistic sensory information is rich enough to make this process unnecessary.

Te perceptual systems of the brain enable individuals to see the world around them as stable, even though the sensory information is typically incomplete and rapidly varying. Human and animal brains are structured in a modular way, with different areas processing different kinds of sensory information. Some of these modules take the form of sensory maps, mapping some aspect of the world across part of the brain's surface. Tese different modules are interconnected and infuence each other. For instance, taste is strongly infuenced by smell.

Imagination is the ability to produce images, ideas and sensations in the mind without any immediate input of the senses (such as seeing or hearing). It is also described as the forming of experiences in the mind, which can be recreations of past experiences such as vivid memories with imagined changes or that they are completely invented. Imagination helps make knowledge applicable in solving problems and is fundamental to integrating experience and the learning process. A basic training for imagination is listening to storytelling (narrative), in which the exactness of the chosen words is the fundamental factor to "evoke worlds".

77 Imagination is a cognitive process used in mental functioning and sometimes used in conjunction with psychological imagery. It is considered as such because it involves thinking about possibilities. Te cognate term of mental imagery may be used in psychology for denoting the process of reviving in the mind recollections of objects formerly given in sense perception. Since this use of the term conficts with that of ordinary language, some psychologists have preferred to describe this process as "imaging" or "imagery" or to speak of it as "reproductive" as opposed to "productive" or "constructive" imagination. Constructive imagination is further divided into voluntary top-down imagination driven by the prefrontal cortex, that is called mental synthesis, and spontaneous bottom up involuntary generation of novel images that occurs during dreaming. Imagined images, both novel and recalled, are seen with the "mind's eye".

Imagination, however, is not considered to be exclusively a cognitive activity because it is also linked to the body and place, particularly that it also involves setting up relationships with materials and people, precluding the sense that imagination is locked away in the head.[9]

Imagination can also be expressed through stories such as fairy tales or fantasies. Children often use such narratives and pretend play in order to exercise their imaginations. When children develop fantasy they play at two levels: frst, they use role playing to act out what they have developed with their imagination, and at the second level they play again with their make- believe situation by acting as if what they have developed is an actual reality.

Te notion of a "mind's eye" goes back at least to Cicero's reference to mentis oculi during his discussion of the orator's appropriate use of simile.

In this discussion, Cicero observed that allusions to "the Syrtis of his patrimony" and "the Charybdis of his possessions" involved similes that were "too far- fetched"; and he advised the orator to, instead, just speak of "the rock" and "the gulf" (respectively) — on the grounds that "the eyes of the mind are more easily directed to those objects which we have seen, than to those which we have only heard".

Te concept of "the mind's eye" frst appeared in English in Chaucer's (c.1387) Man of Law's Tale in his Canterbury Tales, where he tells us that one of the three men dwelling in a castle was blind, and could only see with "the eyes of his mind"; namely, those eyes "with which all men see after they have become blind”.

For distintion always check perception against imagination and vice versa, the two compliment each other too a perfection. Memory is the faculty of the mind by which information is encoded, stored, and retrieved.

Memory is vital to experiences and related to limbic systems, it is the retention of information over time for the purpose of infuencing future action. If we could not remember past events, we could not learn or develop language, relationships, nor personal identity (Eysenck, 2012).

Often memory is understood as an informational processing system with explicit and implicit functioning that is made up of a sensory processor, short-term (or working) memory, and long-term memory (Baddely, 2007). Te sensory processor allows information from the outside world to be sensed in the form of chemical and physical stimuli and attended to with various levels of focus and intent. Working memory serves as an encoding and retrieval processor.

Information in the form of stimuli is encoded in accordance with explicit or implicit functions by the working memory processor. Te working memory also retrieves information from previously stored material. Finally, the function of long-term memory is to store data through various categorical models or systems (Baddely, 2007).

Explicit and implicit functions of memory are also known as declarative and non-declarative systems (Squire, 2009). Tese systems involve the purposeful intention of memory retrieval and storage, or lack thereof. Declarative, or explicit, memory is the conscious storage and recollection of data (Graf & Stacker, 1985). Under declarative memory resides semantic and episodic memory. Semantic memory refers to memory that is encoded with specifc meaning (Eysenck, 2012), while episodic memory refers to information that is encoded along a spatial and temporal plane (Schacter & Addis, 2007; Szpunar, 2010). Declarative memory is usually the primary process thought of when referencing memory (Eysenck, 2012).

Non-declarative, or implicit, memory is the unconscious storage and recollection of information (Foerde & Poldrack, 2009). An example of a non-declarative process would be the unconscious learning or retrieval of information by way of procedural memory, or a priming phenomenon (Eysenck, 2012; Foerde & Poldrack, 2009; Tulving & Schacter, 1990). Priming is the process of subliminally arousing specifc responses from memory and shows that not all memory is consciously activated (Tulving & Schacter, 1990), whereas procedural memory is the slow and gradual learning of skills that often occurs without conscious attention to learning (Eysenck, 2012; Foerde & Poldrack, 2009).

78 Memory may not be a perfect processor, and is aﬀected by many factors. Te manner information is encoded, stored, and retrieved can all be corrupted. Te amount of attention given new stimuli can diminish the amount of information that becomes encoded for storage (Eysenck, 2012). Also, the storage process can become corrupted by physical damage to areas of the brain that are associated with memory storage, such as the hippocampus (Squire, 2009). Finally, the retrieval of information from long-term memory can be disrupted because of decay within long-term memory (Eysenck, 2012). Normal functioning, decay over time, and brain damage all aﬀect the accuracy and capacity of memory.

Memory loss is usually described as forgetfulness or amnesia.

Cognition is "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses processes such as knowledge, attention, memory and working memory, judgment and evaluation, reasoning and "computation", problem solving and decision making, comprehension and production of language. Human cognition is conscious and unconscious, concrete or abstract, as well as intuitive (like knowledge of a language) and conceptual (like a model of a language). Cognitive processes use existing knowledge and generate new knowledge.

Te processes are analyzed from different perspectives within different contexts, notably in the felds of linguistics, anesthesia, neuroscience, psychiatry, psychology, education, philosophy, anthropology, biology, systemics, logic, and computer science. Tese and other different approaches to the analysis of cognition are synthesised in the developing feld of cognitive science, a progressively autonomous academic discipline. Within psychology and philosophy, the concept of cognition is closely related to abstract concepts such as mind and intelligence. It encompasses the mental functions, mental processes (thoughts), and states of intelligent entities (humans, collaborative groups, human organizations, highly autonomous machines, and artifcial intelligences).

Tus, the term's usage varies across disciplines; for example, in psychology and cognitive science, "cognition" usually refers to an information processing view of an individual's psychological functions. It is also used in a branch of social psychology called social cognition to explain attitudes, attribution, and group dynamics. In cognitive psychology and cognitive engineering, cognition is typically assumed to be information processing in a participant’s or operator’s mind or brain. Cognition can in some specifc and abstract sense also be artifcial. Te term "cognition" is often incorrectly used to mean "cognitive abilities" or "cognitive skills".

Cognitive science is the interdisciplinary, scientifc study of the mind and its processes. It examines the nature, the tasks, and the functions of cognition (in a broad sense). Cognitive scientists study intelligence and behavior, with a focus on how nervous systems represent, process, and transform information. Mental faculties of concern to cognitive scientists include language, perception, memory, attention, reasoning, and emotion; to understand these faculties, cognitive scientists borrow from felds such as linguistics, psychology, artifcial intelligence, philosophy, neuroscience, and anthropology. Te typical analysis of cognitive science spans many levels of organization, from learning and decision to logic and planning; from neural circuitry to modular brain organization. Te fundamental concept of cognitive science is that "thinking can best be understood in terms of representational structures in the mind and computational procedures that operate on those structures."

Te cognitive sciences began as an intellectual movement in the 1950s often referred to as the cognitive revolution.

Cognitive psychology is the study of mental processes such as "attention, language use, memory, perception, problem solving, creativity, and thinking". Much of the work derived from cognitive psychology has been integrated into various other modern disciplines of psychological study, including educational psychology, social psychology, personality psychology, abnormal psychology, developmental psychology, and economics.

Information is that which informs. In other words, it is the answer to a question of some kind. It is thus related to data and knowledge, as data represents values attributed to parameters, and knowledge signifes understanding of real things or abstract concepts. As it regards data, the information's existence is not necessarily coupled to an observer (it exists beyond an event horizon, for example), while in the case of knowledge, the information requires a cognitive observer.

Information is conveyed either as the content of a message or through direct or indirect observation of anything. Tat which is perceived can be construed as a message in its own right, and in that sense, information is always conveyed as the content of a message.

Information can be encoded into various forms for transmission and interpretation (for example, information may be encoded into a sequence of signs, or transmitted via a sequence of signals). It can also be encrypted for safe storage and communication.

79 Information reduces uncertainty. Te uncertainty of an event is measured by its probability of occurrence and is inversely proportional to that. Te more uncertain an event, the more information is required to resolve uncertainty of that event. Te bit is a typical unit of information, but other units such as the nat may be used. For example, the information encoded in one "fair" coin fip is log2(2/1) = 1 bit, and in two fair coin fips is log2(4/1) = 2 bits.

Te concept that information is the message has diﬀerent meanings in diﬀerent contexts. Tus the concept of information becomes closely related to notions of constraint, communication, control, data, form, education, knowledge, meaning, understanding, mental stimuli, pattern, perception, representation, and entropy.

In-formation, knowledge formulated in strategic patterns builds notion of in-formation; sense datum in a coherent pattern stimulates perception and memory to recognise or cognate and process knowledge. In-formation is a coherent sub description of the nature in which organisation formulates data to make sense.

Te term meme was coined in Richard Dawkins' 1976 book Te Selfsh Gene, but Dawkins later distanced himself from the resulting feld of study. Analogous to a gene, the meme was conceived as a "unit of culture" (an idea, belief, pattern of behaviour, etc.) which is "hosted" in the minds of one or more individuals, and which can reproduce itself in the sense of jumping from the mind of one person to the mind of another. Tus what would otherwise be regarded as one individual infuencing another to adopt a belief is seen as an idea-replicator reproducing itself in a new host. As with genetics, particularly under a Dawkinsian interpretation, a meme's success may be due to its contribution to the eﬀectiveness of its host. Memes also occur in social networking on digital networks, as a deposit of information usually short in nature.

Te ego (Latin for "I", German: Ich) acts according to the reality principle; i.e., it seeks to please the id's drive in realistic ways that will beneft in the long term rather than bring grief. At the same time, Freud concedes that as the ego "attempts to mediate between id and reality, it is often obliged to cloak the [unconscious] commands of the id with its own preconscious ] rationalizations, to conceal the id's conficts with reality, to profess...to be taking notice of reality even when the id has remained rigid and unyielding." Te reality principle that operates the ego is a regulating mechanism that enables the individual to delay gratifying immediate needs and function eﬀectively in the real world. An example would be to resist the urge to grab other people's belongings, but instead to purchase those items.

Te ego is the organized part of the personality structure that includes defensive, perceptual, intellectual-cognitive, and executive functions. Conscious awareness resides in the ego, although not all of the operations of the ego are conscious. Originally, Freud used the word ego to mean a sense of self, but later revised it to mean a set of psychic functions such as judgment, tolerance, reality testing, control, planning, defense, synthesis of information, intellectual functioning, and memory. Te ego separates out what is real. It helps us to organize our thoughts and make sense of them and the world around us. "Te ego is that part of the id which has been modifed by the direct infuence of the external world. ...Te ego represents what may be called reason and common sense, in contrast to the id, which contains the passions...in its relation to the id it is like a man on horseback, who has to hold in check the superior strength of the horse; with this diﬀerence, that the rider tries to do so with his own strength, while the ego uses borrowed forces." Still worse, "it serves three severe masters...the external world, the super-ego and the id." Its task is to fnd a balance between primitive drives and reality while satisfying the id and super-ego. Its main concern is with the individual's safety and allows some of the id's desires to be expressed, but only when consequences of these actions are marginal. "Tus the ego, driven by the id, confned by the super-ego, repulsed by reality, struggles...[in] bringing about harmony among the forces and infuences working in and upon it," and readily "breaks out in anxiety—realistic anxiety regarding the external world, moral anxiety regarding the super-ego, and neurotic anxiety regarding the strength of the passions in the id." It has to do its best to suit all three, thus is constantly feeling hemmed by the danger of causing discontent on two other sides. It is said, however, that the ego seems to be more loyal to the id, preferring to gloss over the fner details of reality to minimize conficts while pretending to have a regard for reality. But the super-ego is constantly watching every one of the ego's moves and punishes it with feelings of guilt, anxiety, and inferiority.

To overcome this the ego employs defense mechanisms. Te defense mechanisms are not done so directly or consciously. Tey lessen the tension by covering up our impulses that are threatening. Ego defense mechanisms are often used by the ego when id behavior conficts with reality and either society's morals, norms, and taboos or the individual's expectations as a result of the internalization of these morals, norms, and their taboos.

Altruism or selfessness is the principle or practice of concern for the welfare of others. It is a traditional virtue in many cultures and a core aspect of various religious traditions and secular worldviews, though the concept of "others" toward whom concern should be directed can vary among cultures and religions. Altruism or selfessness is the opposite of selfshness. Te word was coined by the French philosopher Auguste Comte in French, as altruisme, for an antonym of egoism. He derived it from the Italian altrui, which in turn was derived from Latin alteri, meaning "other people" or "somebody else".

80 Altruism in biological observations in feld populations of the day organisms can be defned as an individual performing an action which is at a cost to themselves (e.g., pleasure and quality of life, time, probability of survival or reproduction), but benefts, either directly or indirectly, another third-party individual, without the expectation of reciprocity or compensation for that action. Steinberg suggests a defnition for altruism in the clinical setting, that is "intentional and voluntary actions that aim to enhance the welfare of another person in the absence of any quid pro quo external rewards".

Altruism can be distinguished from feelings of loyalty, in that whilst the latter is predicated upon social relationships, altruism does not consider relationships. Much debate exists as to whether "true" altruism is possible in human psychology. Te theory of psychological egoism suggests that no act of sharing, helping or sacrifcing can be described as truly altruistic, as the actor may receive an intrinsic reward in the form of personal gratifcation. Te validity of this argument depends on whether intrinsic rewards qualify as "benefts". Te actor also may not be expecting a reward.

Te term altruism may also refer to an ethical doctrine that claims that individuals are morally obliged to beneft others. Used in this sense, it is usually contrasted with egoism, which is defned as acting to the beneft of one's self.

Denial, displacement, intellectualisation, fantasy, compensation, projection, rationalization, reaction formation, regression, repression, and sublimation were the defense mechanisms Freud identifed. However, his daughter Anna Freud clarifed and identifed the concepts of undoing, suppression, dissociation, idealization, identifcation, introjection, inversion, somatisation, splitting, and substitution.

"Te ego is not sharply separated from the id; its lower portion merges into it.... But the repressed merges into the id as well, and is merely a part of it. Te repressed is only cut oﬀ sharply from the ego by the resistances of repression; it can communicate with the ego through the id." (Sigmund Freud, 1923) In a diagram of the Structural and Topographical Models of Mind, the ego is depicted to be half in the consciousness, while a quarter is in the preconscious and the other quarter lies in the unconscious.

In modern English, ego has many meanings. It could mean one’s self-esteem; an infated sense of self-worth; the conscious- thinking self; or in philosophical terms, one’s self. Ego development is known as the development of multiple processes, cognitive function, defenses, and interpersonal skills or to early adolescence when ego processes are emerged.

In psychology, stress is a feeling of strain and pressure. Also this is one type of psychological pain. Small amounts of stress may be desired, benefcial, and even healthy. Positive stress helps improve athletic performance. It also plays a factor in motivation, adaptation, and reaction to the environment. Excessive amounts of stress, however, may lead to bodily harm. Stress can increase the risk of strokes, heart attacks, ulcers, dwarfsm, and mental illnesses such as depression.

Stress can be external and related to the environment, but may also be created by internal perceptions that cause an individual to experience anxiety or other negative emotions surrounding a situation, such as pressure, discomfort, etc., which they then deem stressful.

Humans experience stress, or perceive things as threatening, when they do not believe that their resources for coping with obstacles (stimuli, people, situations, etc.) are enough for what the circumstances demand. When people think the demands being placed on them exceed their ability to cope, they then perceive stress.

In psychology, the psyche /ˈsaɪki/ is the totality of the human mind, conscious and unconscious. Psychology is the scientifc or objective study of the psyche. Te word has a long history of use in psychology and philosophy, dating back to ancient times, and represents one of the fundamental concepts for understanding human nature from a scientifc point of view. Te English word soul is sometimes used synonymously, especially in older texts.

Psychosis is an abnormal condition of the mind that results in diﬃculties telling what is real and what is not. Symptoms may include false beliefs and seeing or hearing things that others do not see or hear. Other symptoms may include incoherent speech and behavior that is inappropriate for the situation. Tere may also be sleep problems, social withdrawal, lack of motivation, and diﬃculties carrying out daily activities.

Psychosis has many diﬀerent causes. Tese include mental illness, such as schizophrenia or bipolar disorder, sleep deprivation, some medical conditions, certain medications, and drugs such as ‘synthetic derivatives of ’ ailments. mismanaged alcohol or too potent cannabis. One type, known as postpartum psychosis, can occur after childbirth. Te neurotransmitter dopamine is believed to play a role. Te diagnosis of a mental illness requires excluding other potential causes. Testing may be done to check for central nervous system diseases, toxins, or other health problems as a cause.

81 Treatment may include antipsychotic medication, counselling, and social support.Early treatment appears to improve outcomes. Medications appear to have a moderate eﬀect. Outcomes depend on the underlying cause. In the United States about 3% of people develop psychosis at some point in time. Te condition has been described since at least the 4th century BC by Hippocrates and possibly as early as 1,500 BC in the Egyptian Ebers Papyrus.

Tought refers to ideas or arrangements of ideas that are the result of the process of thinking. Tough thinking is an activity considered essential to humanity, there is no consensus as to how it is defned or understood.

Because thought underlies many human actions and interactions, understanding its physical and metaphysical origins, processes, and eﬀects has been a longstanding goal of many academic disciplines including linguistics, psychology, neuroscience, philosophy, artifcial intelligence, biology, sociology and cognitive science.

Tinking allows humans to make sense of, interpret, represent or model the world they experience, and to make predictions about that world. It is therefore helpful to an organism with needs, objectives, and desires as it makes plans or otherwise attempts to accomplish those goals.

A delusion is a mistaken belief that is held with strong conviction even when presented with superior evidence to the contrary. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, or some other misleading eﬀects of perception.

Tey have been found to occur in the context of many pathological states (both general physical and mental) and are of particular diagnostic importance in psychotic disorders including schizophrenia, paraphrenia, manic episodes of bipolar disorder, and psychotic depression.

Imagination, also called the faculty of imagining, is the creative ability to form images, ideas, and sensations in the mind without any immediate input of the senses (such as seeing or hearing). Imagination helps make knowledge applicable in solving problems and is fundamental to integrating experience and the learning process. A basic training for imagination is listening to storytelling (narrative), in which the exactness of the chosen words is the fundamental factor to "evoke worlds".

It is accepted as the innate ability and process of inventing partial or complete personal realms within the mind from elements derived from sense perceptions of the shared world. Te term is technically used in psychology for the process of reviving in the mind, percepts of objects formerly given in sense perception. Since this use of the term conficts with that of ordinary language, some psychologists have preferred to describe this process as "imaging" or "imagery" or to speak of it as "reproductive" as opposed to "productive" or "constructive" imagination. Constructive imagination is further divided into voluntary top-down imagination driven by the prefrontal cortex, that is called mental synthesis, and spontaneous bottom up involuntary generation of novel images that occurs during dreaming. Imagined images, both novel and recalled, are seen with the "mind's eye".

In parapsychology, an apparitional experience is an anomalous experience characterized by the apparent perception of either a living being or an inanimate object without there being any material stimulus for such a perception. Te person experiencing the apparition is awake, excluding dream visions from consideration.

In academic discussion, the term "apparitional experience" is to be preferred to the term "ghost" in respect of the following points:

Te term ghost implies that some element of the human being survives death and, at least under certain circumstances, can make itself perceptible to living human beings. Tere are other competing explanations of apparitional experiences. Firsthand accounts of apparitional experiences diﬀer in many respects from their fctional counterparts in literary or traditional ghost stories and flms. Te content of apparitional experiences includes living beings, both human and animal, and even inanimate objects.

82 interpretation is the attempt at drawing meaning from dreams and searching for an underlying message. Te scientifc study of dreams is called oneirology.

A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. Te content and purpose of dreams are not fully understood, though they have been a topic of scientifc speculation, as well as a subject of philosophical and religious interest, throughout recorded history. Dream interpretation is the attempt at drawing meaning from dreams and searching for an underlying message. Te scientifc study of dreams is called oneirology.

Dreams mainly occur in the rapid-eye movement (REM) stage of sleep—when brain activity is high and resembles that of being awake. REM sleep is revealed by continuous movements of the eyes during sleep. At times, dreams may occur during other stages of sleep. However, these dreams tend to be much less vivid or memorable. Te length of a dream can vary; they may last for a few seconds, or approximately 20–30 minutes. People are more likely to remember the dream if they are awakened during the REM phase. Te average person has three to fve dreams per night, and some may have up to seven; however, most dreams are immediately or quickly forgotten. Dreams tend to last longer as the night progresses. During a full eight-hour night sleep, most dreams occur in the typical two hours of REM.

Opinions about the meaning of dreams have varied and shifted through time and culture. Many endorse the Freudian theory of dreams – that dreams reveal insight into hidden desires and emotions. Other prominent theories include those suggesting that dreams assist in memory formation, problem solving, or simply are a product of random brain activation. Te earliest recorded dreams were acquired from materials dating back approximately 5000 years, in Mesopotamia, where they were documented on clay tablets. In the Greek and Roman periods, the people believed that dreams were direct messages from deities or deceased persons, and that they predicted the future. Some cultures practiced dream incubation with the intention of cultivating dreams that are of prophecy.

Sigmund Freud, who developed the psychological discipline of psychoanalysis, wrote extensively about dream theories and their interpretations in the early 1900s. He explained dreams as manifestations of one's deepest desires and anxieties, often relating to repressed childhood memories or obsessions. Furthermore, he believed that virtually every dream topic, regardless of its content, represented the release of sexual tension. In Te Interpretation of Dreams (1899), Freud developed a psychological technique to interpret dreams and devised a series of guidelines to understand the symbols and motifs that appear in our dreams. In modern times, dreams have been seen as a connection to the unconscious mind. Tey range from normal and ordinary to overly surreal and bizarre. Dreams can have varying natures, such as being frightening, exciting, magical, melancholic, adventurous, or sexual. Te events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming, where the dreamer is self-aware. Dreams can at times make a creative thought occur to the person or give a sense of inspiration.

Hypnosis is a state of human consciousness involving focused attention and reduced peripheral awareness and an enhanced capacity to respond to suggestion. Te term may also refer to an art, skill, or act of inducing hypnosis.

Teories explaining what occurs during hypnosis fall into two groups. Altered state theories see hypnosis as an altered state of mind or trance, marked by a level of awareness diﬀerent from the ordinary conscious state. In contrast, nonstate theories see hypnosis as a form of imaginative role enactment.

During hypnosis, a person is said to have heightened focus and concentration. Te person can concentrate intensely on a specifc thought or memory, while blocking out sources of distraction. Hypnotised subjects are said to show an increased response to suggestions. Hypnosis is usually induced by a procedure known as a hypnotic induction involving a series of preliminary instructions and suggestion. Te use of hypnotism for therapeutic purposes is referred to as "hypnotherapy", while its use as a form of entertainment for an audience is known as "stage hypnosis". Stage hypnosis is often performed by mentalists practicing the art form of mentalism.

A paradox is a statement that, despite apparently sound reasoning from true premises, leads to an apparently self- contradictory or logically unacceptable conclusion. A paradox involves contradictory yet interrelated elements that exist simultaneously and persist over time.

Some logical paradoxes are known to be invalid arguments but are still valuable in promoting critical thinking.

83 Examples outside logic include the ship of Teseus from philosophy (questioning whether a ship repaired over time by replacing each and all of its wooden parts, one at a time, would remain the same ship). Paradoxes can also take the form of images or other media. For example, M.C. Escher featured perspective-based paradoxes in many of his drawings, with walls that are regarded as foors from other points of view, and staircases that appear to climb endlessly.

In common usage, the word "paradox" often refers to statements that may be both true and false i.e. ironic or unexpected, such as "the paradox that standing is more tiring than walking”.

Self is a reference by an individual to the same individual person. Tis reference is necessarily subjective, thus self is a reference by a subject to the same subject. Te sense of having a self – or self-hood – should, however, not be confused with subjectivity itself. Ostensibly, there is a directedness outward from the subject that refers inward, back to its "self" (or itself). Examples of psychiatric conditions where such 'sameness' is broken include depersonalization, which sometimes occur in schizophrenia: the self appears diﬀerent to the subject.

Te frst-person perspective distinguishes self-hood from personal identity. Whereas "identity" is sameness, self-hood implies a frst-person perspective. Conversely, we use "person" as a third-person reference. Personal identity can be impaired in late stage Alzheimer's disease and other neurodegenerative diseases. Finally, the self is distinguishable from "others". Including the distinction between sameness and otherness, the self versus other is a research topic in contemporary philosophy) and contemporary phenomenology (see also psychological phenomenology), psychology, psychiatry, neurology, and neuroscience.

Te nationally funded research Center for Subjectivity in Copenhagen, Denmark, is just one example of the importance of research on the self. More recently, the relationship between the self and technology has generated a research feld called Technoself Studies. Although subjective experience is central to self-hood, the privacy of this experience is only one of many problems in the philosophical and scientifc study of consciousness.

A soliloquy (from Latin solo "to oneself" + loquor "I talk") is a device often used in drama when a character speaks to himself or herself, relating thoughts and feelings, thereby also sharing them with the audience, giving oﬀ the illusion of being a series of unspoken refections. If other characters are present, they keep silent and/or are disregarded by the speaker. Te term soliloquy is distinct from a monologue or an aside: a monologue is a speech where one character addresses other characters; an aside is a (usually short) comment by one character towards the audience, though during the play it may seem like the character is addressing him or herself. Soliloquies were frequently used in dramas but went out of fashion when drama shifted towards realism in the late 18th century. Good examples in literature can be seen in the character of Iago in Shakespeare's Othello. Examples of a present form of soliloquy are found in the sitcom Lizzie McGuire and the political drama House of Cards.

A phobia is a type of anxiety disorder, defned by a persistent fear of an object or situation. Te phobia typically results in a rapid onset of fear and is present for more than six months. Te aﬀected person will go to great lengths to avoid the situation or object, typically to a degree greater than the actual danger posed. If the feared object or situation cannot be avoided, the aﬀected person will have signifcant distress. With blood or injury phobia, fainting may occur. Agoraphobia is often associated with panic attacks. Usually a person has phobias to a number of objects or situations.

Phobias can be divided into specifc phobias, social phobia, and agoraphobia. Types of specifc phobias include those to certain animals, natural environment situations, blood or injury, and specifc situations. Te most common are fear of spiders, fear of snakes, and fear of heights. Occasionally they are triggered by a negative experience with the object or situation. Social phobia is when the situation is feared as the person is worried about others judging them. Agoraphobia is when fear of a situation occurs because it is felt that escape would not be possible.

Specifc phobias should be treated with exposure therapy where the person is introduced to the situation or object in question until the fear resolves. Medications are not useful in this type of phobia. Social phobia and agoraphobia are often treated with some combination of counselling and medication. Medications used include antidepressants, benzodiazepines, or beta-blockers.

Specifc phobias affect about 6–8% of people in the Western world and 2–4% of people in Asia, Africa, and Latin America in a given year. Social phobia affects about 7% of people in the United States and 0.5–2.5% of people in the rest of the world.Agoraphobia affects about 1.7% of people. Women are affected about twice as often as men. Typically onset is around the age of 10 to 17. Rates become lower as people get older. People with phobias are at a higher risk of suicide.

84 Synesthesia is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. People who report a lifelong history of such experiences are known as synesthetes. In one common form of synesthesia, known as grapheme-color synesthesia or color-graphemic synesthesia, letters or numbers are perceived as inherently colored. In spatial-sequence, or number form synesthesia, numbers, months of the year, or days of the week elicit precise locations in space (for example, 1980 may be "farther away" than 1990), or may appear as a three-dimensional map (clockwise or counterclockwise). Synesthetic associations can occur in any combination and any number of senses or cognitive pathways. Little is known about how synesthesia develops. It has been suggested that synesthesia develops during childhood when children are intensively engaged with abstract concepts for the frst time. Tis hypothesis – referred to as semantic vacuum hypothesis – explains why the most common forms of synesthesia are grapheme-color, spatial sequence and number form. Tese are usually the frst abstract concepts that educational systems require children to learn. Only a few types of synesthesia have been scientifcally evaluated. Awareness of synesthetic perceptions varies from person to person. Diﬃculties have been recognized in adequately defning synesthesia. Many diﬀerent phenomena have been included in the term synesthesia ("union of the senses"), and in many cases the terminology seems to be inaccurate. A more accurate but signifcantly less common term may be ideasthesia.

Inspiration (from the Latin inspirare, meaning "to breathe into") refers to an unconscious burst of creativity in a literary, musical, or other artistic endeavour. Te concept has origins in both Hellenism and Hebraism. Te Greeks believed that inspiration or "enthusiasm" came from the muses, as well as the gods Apollo and Dionysus. Similarly, in the Ancient Norse religions, inspiration derives from the gods, such as Odin. Inspiration is also a divine matter in Hebrew poetics. In the Book of Amos the prophet speaks of being overwhelmed by God's voice and compelled to speak. In Christianity, inspiration is a gift of the Holy Spirit.

In the 18th century philosopher John Locke proposed a model of the human mind in which ideas associate or resonate with one another in the mind. In the 19th century, Romantic poets such as Coleridge and Shelley believed that inspiration came to a poet because the poet was attuned to the (divine or mystical) "winds" and because the soul of the poet was able to receive such visions. In the early 20th century, Psychoanalyst Sigmund Freud believed himself to have located inspiration in the inner psyche of the artist. Psychiatrist Carl Gustav Jung's theory of inspiration suggests that an artist is one who was attuned to racial memory, which encoded the archetypes of the human mind.

Te Marxist theory of art sees it as the expression of the friction between economic base and economic superstructural positions, or as an unaware dialog of competing ideologies, or as an exploitation of a "fssure" in the ruling class's ideology. In modern psychology inspiration is not frequently studied, but it is generally seen as an entirely internal process.

Déjà vu (/ˌdeɪʒɑː ˈvuː, - ˈvjuː/; French pronunciation: [deʒa vy] is the feeling that the situation currently being experienced has already been experienced in the past. Déjà vu is a feeling of familiarity, and déjà vécu (the feeling of having "already lived through" something) is a feeling of recollection. Scientifc approaches reject the explanation of déjà vu as "precognition" or "prophecy", but rather explain it as an anomaly of memory, which creates a distinct impression that an experience is "being recalled". Tis explanation is supported by the fact that the sense of "recollection" at the time is strong in most cases, but the circumstances of the "previous" experience (when, where, and how the earlier experience occurred) are uncertain or believed to be impossible. Two types of déjà vu are suggested to exist: the pathological type of déjà vu usually associated with epilepsy and the non-pathological which is a characteristic of healthy people and psychological phenomena. A 2004 review claimed that approximately two-thirds of the population have had déjà vu experiences. Other studies confrm that déjà vu is a common experience in healthy individuals, with between 31% and 96% of individuals reporting it. Déjà vu experiences that are unusually prolonged or frequent, or in association with other symptoms such as hallucinations, may be an indicator of neurological or psychiatric illness. Te phrase comes from French, literally meaning "already seen".

Precognition (from the Latin prae-, "before" and cognitio, "acquiring knowledge"), also called prescience, future vision, future sight is an alleged psychic ability to see events in the future. As with other forms of extrasensory perception, there is no reliable scientifc evidence that precognition is a real ability possessed by anyone and it is widely considered to be pseudoscience. Specifcally, precognition appears to violate the principle that an eﬀect cannot occur before its cause. Despite the lack of scientifc evidence, many people believe it is a real phenomenon. Tere are many reports of precognition and it remains a topic of research and discussion within the parapsychology community.

Hypochondriasis or hypochondria is a condition in which a person is inordinately worried about having a serious illness. An old concept, its meaning has repeatedly changed due to redefnitions in its source metaphors. It has been claimed that this debilitating condition results from an inaccurate perception of the condition of body or mind despite the absence of an actual medical diagnosis. An individual with hypochondriasis is known as a hypochondriac. Hypochondriacs become unduly alarmed about any physical or psychological symptoms they detect, no matter how minor the symptom may be, and are convinced that they have, or are about to be diagnosed with, a serious illness. Often, hypochondria persists even 85 after a physician has evaluated a person and reassured them that their concerns about symptoms do not have an underlying medical basis or, if there is a medical illness, their concerns are far in excess of what is appropriate for the level of disease. Many hypochondriacs focus on a particular symptom as the catalyst of their worrying, such as gastro-intestinal problems, palpitations, or muscle fatigue. To qualify for the diagnosis of hypochondria the symptoms must have been experienced for at least 6 months. Te DSM-IV-TR defnes this disorder, "Hypochondriasis", as a somatoform disorder and one study has shown it to aﬀect about 3% of the visitors to primary care settings. Te newly published DSM-5 replaces the diagnosis of hypochondriasis with the diagnoses of "somatic symptom disorder" and "illness anxiety disorder”. Hypochondria is often characterized by fears that minor bodily or mental symptoms may indicate a serious illness, constant self-examination and self-diagnosis, and a preoccupation with one's body. Many individuals with hypochondriasis express doubt and disbelief in the doctors' diagnosis, and report that doctors’ reassurance about an absence of a serious medical condition is unconvincing, or short-lasting. Additionally, many hypochondriacs experience elevated blood pressure, stress, and anxiety in the presence of doctors or while occupying a medical facility, a condition known as "white coat syndrome". Many hypochondriacs require constant reassurance, either from doctors, family, or friends, and the disorder can become a debilitating challenge for the individual with hypochondriasis, as well as his or her family and friends. Some hypochondriacal individuals completely avoid any reminder of illness, whereas others frequently visit medical facilities, sometimes obsessively. Some suﬀerers may never speak about it.

A spectrum disorder is a mental disorder that includes a range of linked conditions, sometimes also extending to include singular symptoms and traits. Te diﬀerent elements of a spectrum either have a similar appearance or are thought to be caused by the same underlying mechanism. In either case, a spectrum approach is taken because there appears to be "not a unitary disorder but rather a syndrome composed of subgroups". Te spectrum may represent a range of severity, comprising relatively "severe" mental disorders through to relatively "mild and nonclinical defcits”.

In some cases, a spectrum approach joins together conditions that were previously considered separately. A notable example of this trend is the autism spectrum, where conditions on this spectrum may now all be referred to as autism spectrum disorders. In other cases, what was treated as a single disorder comes to be seen (or seen once again) as comprising a range of types, a notable example being the bipolar spectrum. A spectrum approach may also expand the type or the severity of issues which are included, which may lessen the gap with other diagnoses or with what is considered "normal". Proponents of this approach argue that it is in line with evidence of gradations in the type or severity of symptoms in the general population, and helps reduce the stigma associated with a diagnosis. Critics, however, argue that it can take attention and resources away from the most serious conditions associated with the most disability, or on the other hand could unduly medicalize problems which are simply challenges people face in life.

Te visible color spectrum: Te term spectrum was originally used in physics to indicate an apparent qualitative distinction arising from a quantitative continuum (i.e. a series of distinct colors experienced when a beam of white light is dispersed by a prism according to wavelength). Isaac Newton frst used the word spectrum (Latin for "appearance" or "apparition") in print in 1671, in describing his experiments in optics.

Te term was frst used by analogy in psychiatry with a slightly diﬀerent connotation, to identify a group of conditions that is qualitatively distinct in appearance but believed to be related from an underlying pathogenic point of view. It has been noted that for clinicians trained after the publication of DSM-III (1980), the spectrum concept in psychiatry may be relatively new, but that it has a long and distinguished history that dates back to Emil Kraepelin and beyond. A dimensional concept was proposed by Ernst Kretschmer in 1921 for schizophrenia (schizothymic – schizoid – schizophrenic) and for aﬀective disorders (cyclothymic temperament – cycloid 'psychopathy' – manic-depressive disorder), as well as by Eugen Bleuler in 1922. Te term "spectrum" was frst used in psychiatry in 1968 in regard to a postulated schizophrenia spectrum, at that time meaning a linking together of what were then called "schizoid personalities", in people diagnosed with schizophrenia and their genetic relatives (see Seymour S. Kety).

A spectrum approach sometimes starts with the nuclear, classic DSM diagnostic criteria for a disorder (or may join together several disorders), and then include an additional broad range of issues such as temperaments or traits, lifestyle, behavioral patterns, and personality characteristics.

In addition, the term 'spectrum' may be used interchangeably with continuum, although the latter goes further in suggesting a direct straight line with no signifcant discontinuities. Under some continuum models, there are no set types or categories at all, only diﬀerent dimensions along which everyone varies (hence a dimensional approach).

An example can be found in personality or temperament models. For example, a model that was derived from linguistic expressions of individual diﬀerences is subdivided into the Big Five personality traits, where everyone can be assigned a score along each of the fve dimensions. Tis is by contrast to models of 'personality types' or temperament, where some have a certain type and some do not. Similarly, in the classifcation of mental disorders, a dimensional approach, which is being

86 considered for the DSM-V, would involve everyone having a score on personality trait measures. A categorical approach would only look for the presence or absence of certain clusters of symptoms, perhaps with some cut-oﬀ points for severity for some symptoms only, and as a result diagnose some people with personality disorders.

A spectrum approach, by comparison, suggests that although there is a common underlying link, which could be continuous, particular sets of individuals present with particular patterns of symptoms (i.e. syndrome or subtype), reminiscent of the visible spectrum of distinct colors after refraction of light by a prism.

It has been argued that within the data used to develop the DSM system there is a large literature leading to the conclusion that a spectrum classifcation provides a better perspective on phenomenology (appearance and experience) of psychopathology (mental diﬃculties) than a categorical classifcation system. However, the term has a varied history, meaning one thing when referring to a schizophrenia spectrum and another when referring to bipolar or obsessive– compulsive disorder spectrum, for example.

A Generalized anxiety spectrum. Tis spectrum has been defned by duration of symptoms: a type lasting over six months (a DSM-IV criterion), over one month (DSM-III), or lasting two weeks or less (though may recur), and also isolated anxiety symptoms not meeting criteria for any type.

A Social anxiety spectrum. Tis has been defned to span shyness to social anxiety disorder, including typical and atypical presentations, isolated signs and symptoms, and elements of avoidant personality disorder.

A panic-agoraphobia spectrum. Due to the heterogeneity (diversity) found in individual clinical presentations of panic disorder and agoraphobia, attempts have been made to identify symptom clusters in addition to those included in the DSM diagnoses, including through the development of a dimensional questionnaire measure.

A Post-traumatic stress spectrum or trauma and loss spectrum. Work in this area has sought to go beyond the DSM category and consider in more detail a spectrum of severity of symptoms (rather than just presence or absence for diagnostic purposes), as well as a spectrum in terms of the nature of the stressor (e.g. the traumatic incident) and a spectrum of how people respond to trauma. Tis identifes a signifcant amount of symptoms and impairment below threshold for DSM diagnosis but nevertheless important, and potentially also present in other disorders a person might be diagnosed with.

A depersonalization-derealization spectrum. Although the DSM identifes only a chronic and severe form of depersonalization disorder, and the ICD a 'depersonalization-derealization syndrome', a spectrum of severity has long been identifed, including short-lasting episodes commonly experienced in the general population and often associated with other disorders.

A mood disorder (aﬀective) spectrum or bipolar spectrum or depressive spectrum.[29] Tese approaches have expanded out in diﬀerent directions. On the one hand, work on major depressive disorder has identifed a spectrum of subcategories and subthreshold symptoms which are prevalent, recurrent and associated with treatment needs. People are found to move between the subtypes and the main diagnostic type over time, suggesting a spectrum. Tis spectrum can include already recognised categories of minor depressive disorder, 'melancholic depression' and various kinds of atypical depression.

Going in another direction, numerous links and overlaps have been found between major depressive disorder and bipolar syndromes, including mixed states (simultaneous depression and mania or hypomania). Hypomanic ('below manic') and more rarely manic signs and symptoms have been found in a signifcant number of cases of major depressive disorder, suggesting not a categorical distinction but a dimension of frequency which is higher in bipolar II and higher again in bipolar I.[30] In addition, numerous subtypes of bipolar have been proposed beyond the types already in the DSM (which includes a milder form called cyclothymia). Tese extra subgroups have been defned in terms of more detailed gradations of mood severity, or the rapidity of cycling, or the extent or nature of psychotic symptoms. Furthermore, due to shared characteristics between some types of Bipolar disorder and Borderline Personality Disorder, some researchers have suggested they may both lie on a spectrum of aﬀective disorders, although others see more links to post-trauma syndromes.

A spectrum of drug use, drug abuse and substance dependence. One spectrum of this type, adopted by the Health Oﬃcers Council of British Columbia in 2005, does not employ loaded terms and distinctions such as "use" vs. "abuse", but explicitly recognizes a spectrum ranging from potentially benefcial to chronic dependence (also known as addiction). Te model includes the role not just of the individual but of society, culture and availability of substances. In concert with the identifed spectrum of drug use, a spectrum of policy approaches was identifed which depended partly on whether the drug in question was available in a legal, for-proft commercial economy, or at the other of the spectrum only in a criminal/ prohibition, black-market economy.[32] In addition, a standardized questionnaire has been developed in psychiatry based on a spectrum concept of substance use.

87 Te interpretative key of "Spectrum", developed from the concept of Related Disorders has been considered also in Paraphilias.[clarifcation needed]

Paraphilic behavior is triggered by thoughts or urges that are psychopathologically close to obsessive impulsive area. Hollander (1996) includes in the obsessive- compulsive spectrum neurological related obsessive disorders, body perception related disorders and impulsivity-compulsivity disorders. In this continuum from impulsivity to compulsivity is particularly hard to fnd a clear borderline between the two entities.

On this point of view, paraphilias represent such as sexual behaviors due to a high impulsivity-compulsivity drive. It is diﬃcult to distinguish impulsivity from compulsivity: sometimes paraphilic behaviors are prone to achieve pleasure (desire or fantasy), in some other cases these attitudes are merely expressions of anxiety, and the behavioral perversion is an attempt to reduce anxiety. In the last case, the pleasure gained is short in time and is followed by a new increase in anxiety levels, such as it can be seen in an obsessive patient after he performs his compulsion.[citation needed]

Eibl-Eibelsfeldt (1984) underlines a female sexual arousal condition during fight and fear reactions. Some women, with masochistic traits, can reach orgasm in such conditions.

Various higher-level types of spectrum have also been proposed, that subsume conditions into fewer but broader overarching groups.

One psychological model based on factor analysis, originating from developmental studies but also applied to adults, posits that many disorders fall on either an "internalizing" spectrum (characterized by negative affectivity; subdivides into a "distress" subspectrum and a "fear" subspectrum) or an "externalizing" spectrum (characterized by negativity affectivity plus disinhibition). Tese spectra are hypothetically linked to underlying variation in some of the Big fve personality traits. Another theoretical model proposes that the dimensions of fear and anger, defned in a broad sense, underlie a broad spectrum of mood, behavioral and personality disorders. In this model, different combinations of excessive or defcient fear and anger correspond to different neuropsychological temperament types hypothesized to underlie the spectrum of disorders.

Similar approaches refer to the overall 'architecture' or 'meta-structure', particularly in relation to the development of the DSM or ICD systems. Five proposed meta-structure groupings were recently proposed in this way, based on views and evidence relating to risk factors and clinical presention. Te clusters of disorder that emerged were described as neurocognitive (identifed mainly by neural substrate abnormalities), neurodevelopmental (identifed mainly by early and continuing cognitive defcits), psychosis (identifed mainly by clinical features and biomarkers for information processing defcits), emotional (identifed mainly by being preceded by a temperament of negative emotionality), and externalizing (identifed mainly be being preceded by disinhibition).[39] However, the analysis was not necessarily able to validate one arrangement over others. From a psychological point of view, it has been suggested that the underlying phenomena are too complex, inter-related and continuous – with too poorly understood a biological or environmental basis – to expect that everything can be mapped into a set of categories for all purposes. In this context the overall system of classifcation is to some extent arbitrary, and could be thought of as a user inferface which may need to satisfy diﬀerent purposes.

2: Physiology

Te spiritual side to physiology involves studying spiritual substance created by the mind and is held and bound by the body via the soul, these are the organs and muscle made of of light and dark frequencies of spiritual substance, colour and shape

88 that give distinction and pedigree to the physical organs. Physical organs cannot function properly without physiological counterparts, they relate to the mind and its summoning of energy for the body. Prayer can heal the spiritual physiology of the body that in turn completely heals the physical body.

Physiology (/ˌfɪziˈɒlədʒi/; from Ancient Greek φύσις (physis), meaning 'nature, origin', and -λογία (-logia), meaning 'study of') is the scientifc study of mechanisms, and their interactions, which works within a living system. A sub-discipline of biology, its focus is in how spirit, organisms, organ systems, organs, cells, and biomolecules carry out the chemical or physical functions that exist in a living system. Given the size of the feld, it is divided into, among others, animal physiology (including that of humans), plant physiology, cellular physiology, microbial physiology (microbial metabolism), bacterial physiology, and viral physiology.

Central to an understanding of physiological functioning is its integrated nature with other disciplines such as chemistry and physics, coordinated homeostatic control mechanisms, and continuous communication between cells.

Human physiology seeks to understand the mechanisms that work to keep the human body alive and functioning, through scientifc enquiry into the nature of spiritual, mechanical, physical, and biochemical functions of humans, their organs, and the cells of which they are composed. Te principal level of focus of physiology is at the level of organs and systems within systems. Te endocrine and nervous systems play major roles in the reception and transmission of signals. that integrate function in animals. Homeostasis is a major aspect with regard to such interactions within plants as well as animals. Te biological basis of the study of physiology, integration refers to the overlap of many functions of the systems of the human body, as well as its accompanied form. It is achieved through communication that occurs in a variety of ways, spiritual, electrical and chemical.

Much of the foundation of knowledge in human physiology was provided by insights from God. Due to the frequent connection between form and function, physiology and anatomy are intrinsically linked and are studied in tandem as part of a medical pathology. All Physiology begins with spiritual substance.

A chemical substance is a form of matter having constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be simple substances, chemical compounds, or alloys. Chemical elements may or may not be included in the defnition, depending on expert viewpoint.

Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refned sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specifed according to the intended use of the chemical.

Chemical substances exist as solids, liquids, gases, or plasma, and may change between these phases of matter with changes in temperature or pressure. Chemical substances may be combined or converted to others by means of chemical reactions.

Aristotle famously contends that every physical object is a compound of matter and form. Tis doctrine has been dubbed “hylomorphism”, a portmanteau of the Greek words for matter (hulê) and form (eidos or morphê). Highly infuential in the development of Medieval philosophy, Aristotle’s hylomorphism has also enjoyed something of a renaissance in contemporary metaphysics.

While the basic idea of hylomorphism is easy to grasp, much remains unclear beneath the surface. Aristotle introduces matter and form, in the Physics, to account for changes in the natural world, where he is particularly interested in explaining how substances come into existence even though, as he maintains, there is no generation ex nihilo, that is that nothing comes from nothing. In this connection, he develops a general hylomorphic framework, which he then extends by putting it to work in a variety of contexts. For example, he deploys it in his Metaphysics, where he argues that form is what unifes some matter into a single object, the compound of the two; he appeals to it in his De Anima, by treating soul and body as a special case of form and matter and by analyzing perception as the reception of form without matter; and he suggests in the Politics that a constitution is the form of a polis and the citizens its matter, partly on the grounds that the constitution serves to unify the body politic.

Matter, form, and the compound of matter and form may all be considered subjects, Aristotle tells us, but which of them is substance? Te subject criterion by itself leads to the answer that the substance of x is an entirely indeterminate matter of 89 which x is composed. For form is predicated of matter as subject, and one can always analyze a hylomorphic compound into its predicates and the subject of which they are predicated. And when all predicates have been removed (in thought), the subject that remains is nothing at all in its own right—an entity all of whose properties are accidental to it (1029a12–27). Te resulting subject is matter from which all form has been expunged. (Traditional scholarship calls this “prime matter,” but Aristotle does not here indicate whether he thinks there actually is such a thing.) So the subject criterion leads to the answer that the substance of x is the formless matter of which it is ultimately composed.

Physiology: Substance theory, or substance–attribute theory, is an ontological theory about objecthood positing that a substance is distinct from its properties. A thing-in-itself is a property-bearer that must be distinguished from the properties it bears.[1]

Substance is a key concept in ontology and metaphysics, which may be classifed into monist, dualist, or pluralist varieties according to how many substances or individuals are said to populate, furnish, or exist in the world. According to monistic views, there is only one substance. Stoicism and Spinoza, for example, hold monistic views, that pneuma or God, respectively, is the one substance in the world. Tese modes of thinking are sometimes associated with the idea of immanence. Dualism sees the world as being composed of two fundamental substances (for example, the Cartesian substance dualism of mind and matter). Pluralist philosophies include Plato's Teory of Forms and Aristotle's hylomorphic categories.

Hylomorphism (or hylemorphism) is a philosophical theory developed by Aristotle, which conceives being (ousia) as a compound of matter and form. Te word is a 19th-century term formed from the Greek words ὕλη hyle, "wood, matter", and μορφή, morphē, “form".

Medieval philosophers who used Aristotelian concepts frequently distinguished between substantial forms and accidental forms. A substance necessarily possesses at least one substantial form. It may also possess a variety of accidental forms. For Aristotle, a "substance" (ousia) is an individual thing—for example, an individual man or an individual horse.[9] Te substantial form of substance S consists of S's essential properties,[10] the properties that S's matter needs in order to be the kind of substance that S is.[11] In contrast, S's accidental forms are S's non-essential properties,[12] properties that S can lose or gain without changing into a diﬀerent kind of substance.[13]

In some cases, a substance's matter will itself be a substance. If substance A is made out of substance B, then substance B is the matter of substance A. However, what is the matter of a substance that is not made out of any other substance? According to Aristotelians, such a substance has only "prime matter" as its matter. Prime matter is matter with no substantial form of its own.[14] Tus, it can change into various kinds of substances without remaining any kind of substance all the time.[1

Aristotle applies his theory of hylomorphism to living things. He defnes a soul as that which makes a living thing alive.[16] Life is a property of living things, just as knowledge and health are.[17] Terefore, a soul is a form—that is, a specifying principle or cause—of a living thing.[18] Furthermore, Aristotle says that a soul is related to its body as form to matter.[19]

Hence, Aristotle argues, there is no problem in explaining the unity of body and soul, just as there is no problem in explaining the unity of wax and its shape.[20] Just as a wax object consists of wax with a certain shape, so a living organism consists of a body with the property of life, which is its soul. On the basis of his hylomorphic theory, Aristotle rejects the Pythagorean doctrine of reincarnation, ridiculing the notion that just any soul could inhabit just any body.[21]

Aristotle identifes the soul with the body's structure.[22] According to one interpretation of Aristotle, a properly organized body is already alive simply by virtue of its structure.[23] However, according to another interpretation, the property of life —that is, the soul—is something in addition to the body's structure. Robinson uses the analogy of a car to explain this second interpretation. A running car is running not only because of its structure but also because of the activity in its engine. [24] Likewise, according to this second interpretation, a living body is alive not only because of its structure but also because of an additional property: the soul, which a properly organized body needs in order to be alive.[25] John Vella uses Frankenstein's monster to illustrate the second interpretation: [26] the corpse lying on Frankenstein's table is already a fully organized human body, but it is not yet alive; when Frankenstein activates his machine, the corpse gains a new property, the property of life, which Aristotle would call the soul. Te spirit joins the body for life after 2 minutes prayer then you have confuence with God too. After a lifetime and nerd the spirit goes to join the soul tree a collection of past adventure that can inform the body on earth, hence substance structure is more alike too intercommunication and interaction with Spirit than Soul.

90 Living bodies: Some scholars have pointed out a problem facing Aristotle's theory of soul-body hylomorphism.[27] According to Aristotle, a living thing's matter is its body, which needs a soul in order to be alive. Similarly, a bronze sphere's matter is bronze, which needs roundness in order to be a sphere. Now, bronze remains the same bronze after ceasing to be a sphere. Terefore, it seems that a body should remain the same body after death.[28] However, Aristotle implies that a body is no longer the same body after death.[29] Moreover, Aristotle says that a body that has lost its soul is no longer potentially alive.[30] But if a living thing's matter is its body, then that body should be potentially alive by defnition.

One approach to resolving this problem[31] relies on the fact that a living body is constantly replacing old matter with new. A fve-year-old body consists of diﬀerent matter than does the same person's seventy-year-old body. If the fve-year-old body and the seventy-year-old body consist of diﬀerent matter, then what makes them the same body? Te answer is presumably the soul. Because the fve-year-old and the seventy-year-old bodies share a soul—that is, the person's life— we can identify them both as the body. Apart from the soul, we cannot identify what collection of matter is the body. Terefore, a person's body is no longer that person's body after it dies.

Another approach to resolving the problem[32] relies on a distinction between "proximate" and "non-proximate" matter. When Aristotle says that the body is matter for a living thing, he may be using the word "body" to refer to the matter that makes up the fully organized body, rather than the fully organized body itself. Unlike the fully organized body, this "body" remains the same thing even after death. In contrast, when he says that the body is no longer the same after its death, he is using the word "body" to refer to the fully organized body.

Aristotle says that the intellect (nous), the ability to think, has no bodily organ (in contrast with other psychological abilities, such as sense-perception and imagination).[33] In fact, he says that it is not mixed with the body[34] and suggests that it can exist apart from the body.[35] Tis seems to contradict Aristotle's claim that the soul is a form or property of the body. To complicate matters further, Aristotle distinguishes between two kinds, or two parts, of intellect.[36] Tese two intellectual powers are traditionally called the "passive intellect" and the "active (or agent) intellect".[37] Tus, interpreters of Aristotle have faced the problem of explaining how the intellect fts into Aristotle's hylomorphic theory of the soul.

According to one interpretation, a person's ability to think (unlike his other psychological abilities) belongs to some incorporeal organ distinct from his body.[38] Tis would amount to a form of dualism.[39] However, according to some scholars, it would not be a full-fedged Cartesian dualism.[40] Tis interpretation creates what Robert Pasnau has called the "mind-soul problem": if the intellect belongs to an entity distinct from the body, and the soul is the form of the body, then how is the intellect part of the soul?[41]

Another interpretation rests on the distinction between the passive intellect and the agent intellect. According to this interpretation, the passive intellect is a property of the body, while the agent intellect is a substance distinct from the body. [42][43] Some proponents of this interpretation think that each person has his own agent intellect, which presumably separates from the body at death. Others interpret the agent intellect as a single divine being, perhaps the unmoved mover, Aristotle's God.

A third interpretation[48] relies on the theory that an individual form is capable of having properties of its own.[49] According to this interpretation, the soul is a property of the body, but the ability to think is a property of the soul itself, not of the body. If that is the case, then the soul is the body's form and yet thinking need not involve any bodily organ.[50]

Claiming that X’s body was X’s only substantial form commanded by X’s spirit and God through prayer, although X also had numerous accidental forms that accounted for X’s nonessential features.[54] Aquinas defned a substantial form as that which makes X's matter constitute X, which in the case of a human being is rational capacity.[55] He attributed all other features of a human being to accidental forms.[56] However, Aquinas did not claim that the soul was identical to the person. [57] He held that a proper human being is a composite of form and matter, specifcally prime matter. Form and matter taken separately may retain some of the attributes of a human being but are nonetheless not identical to that person.[58] So a dead body is not actually or potentially a human being.[59]

Eleonore Stump describes Aquinas' theory of the soul in terms of "confguration". Te body is matter that is "confgured", i.e. structured, while the soul is a "confgured confgurer". In other words, the soul is itself a confgured thing, but it also confgures the body.[60] A dead body is merely matter that was once confgured by the soul. It does not possess the confguring capacity of a human being.

Aquinas believed that rational capacity was a property of the soul alone, not of any bodily organ.[61] However, he did believe that the brain had some basic cognitive function.[62] Aquinas’ attribution of rational capacity to the soul allowed him to claim that disembodied souls could retain their rational capacity, although he was adamant that such a state was unnatural.[63]

91 Aristotle holds a teleological worldview: he sees the universe as inherently purposeful. Basically, Aristotle claims that potentiality exists for the sake of actuality. [64] Tus, matter exists for the sake of receiving its form,[65] and an organism has sight for the sake of seeing.[66] Now, each thing has certain potentialities as a result of its form. Because of its form, a snake has the potential to slither; we can say that the snake ought to slither. Te more a thing achieves its potential, the more it succeeds in achieving its purpose.

Aristotle bases his ethical theory on this teleological worldview. Because of his form, a human being has certain abilities. Hence, his purpose in life is to exercise those abilities as well and as fully as possible.[67] Now, the most characteristic human ability, which is not included in the form of any other organism, is the ability to think.[68] Terefore, the best human life is a life lived rationally

Hylozoism is the philosophical point of view that matter is in some sense alive. Although there is a distinction between possessing a mind (hylopsychism) and possessing life (hylozoism); in practice this division is diﬃcult to maintain, because the ancient hylozoists not only regarded the spirits of the material universe and plant world as alive, but also as more or less conscious. Whereas animism tends to view life as taking the form of discrete spirits, and panpsychism tends to refer to strictly philosophical views like that of Gottfried Wilhelm Leibniz, hylozoism refers largely to views such as those of the earliest Greek philosophers (6th and 5th centuries BC), who treated the magnet as alive because of its attractive powers (Tales), or air as divine (Anaximenes), perhaps because of its apparently spontaneous power of movement, or because of its essentiality for life in animals. Later this primitive hylozoism reappeared in modifed forms. Some scholars[who?] have since claimed that the term hylozoism should properly be used only where body and soul are explicitly distinguished, the distinction then being rejected as invalid. Nevertheless, hylozoism remains logically distinct both from early forms of animism, which personify nature, and from panpsychism, which attributes some form of consciousness or sensation to all matter.

Some of the ancient Greek philosophers taught a version of hylozoism, as they, however vaguely, conceived the elemental matter as being in some sense animate if not actually conscious and conative (a directed eﬀort, a striving or tendency; a nisus). Tales, Anaximenes, and Heraclitus all taught that there is a form of life in all material objects, and the Stoics believed that a world and individual and community spirit was the vital force of the universal existance. Note that these philosophies did not necessarily hold that material objects had separate life or identity, only that they had life, either as part of an overriding entity or as living but insensible entities.

In the Renaissance, Bernardino Telesio, Paracelsus, Cardanus, and Giordano Bruno revived the doctrine of hylozoism. Te latter, for example, held a form of Christian pantheism, wherein God is the source, cause, medium, and end of all things, and therefore all things are participatory in the ongoing Godhead. Bruno's ideas were so radical that he was entirely rejected by the Roman Catholic Church as well as excommunicated from a few Protestant groups, and he was eventually burned at the stake for various heresies. Telesio, on the other hand, began from an Aristotelian basis and, through radical empiricism, came to believe that a living force was what informed all matter. Instead of the intellectual universals of Aristotle, he believed that life generated form.

In England, some of the Cambridge Platonists approached hylozoism as well. Both Henry More and Ralph Cudworth (the Younger, 1617–1688), through their reconciliation of Platonic idealism with Christian doctrines of deifc generation, came to see the divine lifeforce as the informing principle in the world. Tus, like Bruno, but not nearly to the extreme, they saw God's generative impulse as giving life to all things that exist. Accordingly, Cudworth, the most systematic metaphysician of the Cambridge Platonist tradition, fought hylozoism. His work is primarily a critique of what he took to be the two principal forms of atheism— materialism and hylozoism.

Cudworth singled out Hobbes not only as a defender of the hylozoic atheism "which attributes life to matter", but also as one going beyond it and defending "hylopathian atheism, which attributes all to matter." Cudworth attempted to show that Hobbes had revived the doctrines of Protagoras and was therefore subject to the criticisms which Plato had deployed against Protagoras in the Teaetetus. On the side of hylozoism, Strato of Lampsacus was the oﬃcial target. However, Cudworth's Dutch friends had reported to him the views which Spinoza was circulating in manuscript. Cudworth remarks in his Preface that he would have ignored hylozoism had he not been aware that a new version of it would shortly be published.[3]

Spinoza's idealism also tends toward hylozoism. In order to hold a balance even between matter and mind, Spinoza combined materialistic with pantheistic hylozoism, by demoting both to mere attributes of the one infnite substance. Although specifcally rejecting identity in inorganic matter, he, like the Cambridge Platonists, sees a life force within, as well as beyond, all matter.

Immanuel Kant presented arguments against hylozoism in the third chapter of his Metaphysische Anfangsgründe der Naturwissenschaften ("First Metaphysical Principles of Natural Science," 1786) and also in his famous Kritik der reinen

92 Vernunft ("Critique of Pure Reason," 1783). Yet, in our times, scientifc hylozoism – whether modifed, or keeping the trend to make all beings conform to some uniform pattern, to which the concept was adhered in modernity by Herbert Spencer, Hermann Lotze, and Ernst Haeckel – was often called upon as a protest against a mechanistic worldview.[4]

In the 19th century, Haeckel developed a materialist form of hylozoism, specially against Rudolf Virchow's and Hermann von Helmholtz's mechanical views of humans and nature. In his Die Welträtsel of 1899 (Te Riddle of the Universe 1901), Haeckel upheld a unity of organic and inorganic nature and derived all actions of both types of matter from natural causes and laws. Tus, his form of hylozoism reverses the usual course by maintaining that living and nonliving things are essentially the same, and by erasing the distinction between the two and stipulating that they behave by a single set of laws.

In contrast, the Argentine-German neurobiological tradition terms hylozoic hiatus all of the parts of nature which can only behave lawfully or nomically and, upon such a feature, are described as lying outside of minds and amid them – i.e. extramentally. Tereby the hylozoic hiatus becomes contraposed to minds deemed able of behaving semoviently, i.e. able of inaugurating new causal series (semovience). Hylozoism in this contemporary neurobiological tradition is thus restricted to the portions of nature behaving nomically inside the minds, namely the minds' sensory reactions (Christfried Jakob's "sensory intonations") whereby minds react to the stimuli coming from the hylozoic hiatus or extramental realm.[5][6]

Martin Buber too takes an approach that is quasi-hylozoic. By maintaining that the essence of things is identifable and separate, although not pre-existing, he can see a soul within each thing.

Te French Pythagorean and Rosicrucian alchemist, Francois Jollivet-Castelot (1874-1937), established a hylozoic esoteric school which combined the insight of spagyrics, chemistry, physics, transmutations and metaphysics. He published many books, one of which was called "L’Hylozoïsme, l’alchimie, les chimistes unitaires" (1896). In his view there was no diﬀerence between spirit and matter except for the degree of frequency and other vibrational conditions.

Te Mormon theologian Orson Pratt taught a form of hylozoism. Alice A. Bailey wrote a book called Te Consciousness of the Atom.[7]

Infuenced by Alice A. Bailey, Charles Webster Leadbeater, and their predecessor Madame Blavatsky, Henry T. Laurency produced voluminous writings describing a hylozoic philosophy.[8]

Infuenced by George Ivanovich Gurdjieﬀ, the English philosopher and mathematician John Godolphin Bennett, in his four-volume work Te Dramatic Universe and his book Energies, developed a six-dimensional framework in which matter- energy takes on 12 levels of hylozoic quality.

Ken Wilber embraces hylozoism to explain subjective experience and provides terms describing the ladder of subjective experience experienced by entities from atoms up to Human beings in the upper left quadrant of his Integral philosophy chart.[9]

Physicist Tomas Brophy, in Te Mechanism Demands a Mysticism, embraces hylozoism as the basis of a framework for re- integrating modern physical science with perennial spiritual philosophy. Brophy coins two additional words to stand with hylozoism as the three possible ontological stances consistent with modern physics. Tus: hylostatism (universe is deterministic, thus “static” in a four-dimensional sense); hylostochastism (universe contains a fundamentally random or stochastic component); hylozoism (universe contains a fundamentally alive aspect).

Architect Christopher Alexander has put forth a theory of the living universe, where life is viewed as a pervasive patterning that extends to what is normally considered non-living things, notably buildings. He wrote a four-volume work called Te Nature of Order which explicates this theory in detail.

Philosopher and ecologist David Abram articulates and elaborates a form of hylozoism grounded in the phenomenology of sensory experience. In his books Becoming Animal and Te Spell of the Sensuous, Abram suggests that matter is never entirely passive in our direct experience, holding rather that material things actively "solicit our attention" or "call our focus," coaxing the perceiving body into an ongoing participation with those things. In the absence of intervening technologies, sensory experience is inherently animistic, disclosing a material feld that is animate and self-organizing from the get-go. Drawing upon contemporary cognitive and natural science as well as the perspectival worldviews of diverse indigenous, oral cultures, Abram proposes a richly pluralist and story-based cosmology, in which matter is alive through and through. Such an ontology is in close accord, he suggests, with our spontaneous perceptual experience; it calls us back to our senses and to the primacy of the sensuous terrain, enjoining a more respectful and ethical relation to the more-than-human community of animals, plants, soils, mountains, waters and weather-patterns that materially sustains us.[10]

93 Bruno Latour's actor-network theory, in the sociology of science, treats non-living things as active agents and thus bears some metaphorical resemblance to hylozoism

Homeostasis can be defned as the stable condition of an organism and of its internal environment; or as the maintenance or regulation of the stable condition, or its equilibrium; or simply as the balance of bodily functions. Te stable condition is the condition of optimal functioning for the organism, and is dependent on many variables, such as body temperature and fuid balance, being kept within certain pre-set limits. Other variables include the pH of extracellular fuid, the concentrations of sodium, potassium and calcium ions, as well as that of the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life.

Homeostasis is brought about by a natural resistance to change in the optimal conditions, and equilibrium is maintained by many regulatory mechanisms. All homeostatic control mechanisms have at least three interdependent components for the variable being regulated: a receptor, a control centre, and an eﬀector. Te receptor is the sensing component that monitors and responds to changes in the environment, either external or internal. Receptors include thermoreceptors, and mechanoreceptors. Control centres include the respiratory centre, and the renin-angiotensin system. An eﬀector is the target acted on, to bring about the change back to the normal state. At the cellular level, receptors include nuclear receptors that bring about changes in gene expression through up-regulation or down- regulation, and act in negative feedback mechanisms. An example of this is in the control of bile acids in the liver.

Some centres such as the renin-angiotensin system, control more than one variable. When the receptor senses a stimulus, it reacts by sending an action potential to a control centre. Te control centre sets the maintenance range, the acceptable upper and lower limits, for the particular variable such as temperature. Te control center responds to the signal by determining an appropriate response and sending signals to an eﬀector which can be one or more muscles, an organ, or a gland. When the signal is received and acted on, negative feedback is fed back to the receptor that stops the need for further signalling.

Te concept of the regulation of the internal environment was described by French physiologist Claude Bernard in 1865, and the word homeostasis was coined by Walter Bradford Cannon in 1926. Homeostasis is an almost exclusively biological term, referring to the concepts described by Bernard and Cannon, concerning the constancy of the internal environment in which the cells of the body live and survive. Te term cybernetics is applied to technological control systems such as thermostats, which function as homeostatic mechanisms, but is often defned much more broadly than the biological term of homeostasis.

Fertilisation or fertilization (see spelling diﬀerences), also known as generative fertilisation, conception, fecundation, syngamy and impregnation, is the fusion of gametes to initiate the development of a new individual organism. Te cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.

Sexual reproduction is a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together, involving a female's large ovum (or egg) and a male's smaller sperm. Each gamete contains half the number of chromosomes of normal cells. Tey are created by a specialized type of cell division, which only occurs in eukaryotic cells, known as meiosis. Te two gametes fuse during fertilization to produce DNA replication and the creation of a single-celled zygote which includes genetic material from both gametes. In a process called genetic recombination, genetic material (DNA) joins up so that homologous chromosome sequences are aligned with each other, and this is followed by exchange of genetic information. Two rounds of cell division then produce four daughter cells with half the number of chromosomes from each original parent cell, and the same number of chromosomes as both parents, though self-fertilization can occur. For instance, in human reproduction each human cell contains 46 chromosomes, 23 pairs, except gamete cells, which only contain 23 chromosomes, so the child will have 23 chromosomes from each parent genetically recombined into 23 pairs. Cell division initiates the development of a new individual organism in multicellular organisms, including animals and plants, for the vast majority of whom this is the primary method of reproduction.

Te evolution of sexual reproduction is a major puzzle because asexual reproduction should be able to outcompete it as every young organism created can bear its own young. Tis implies that an asexual population has an intrinsic capacity to grow more rapidly with each generation. Tis 50% cost is a ftness disadvantage of sexual reproduction. Te two-fold cost of sex includes this cost and the fact that any organism can only pass on 50% of its own genes to its oﬀspring. One defnite advantage of sexual reproduction is that it prevents the accumulation of genetic mutations.

94 Sexual selection is a mode of natural selection in which some individuals out-reproduce others of a population because they are better at securing mates for sexual reproduction. It has been described as "a powerful evolutionary force that does not exist in asexual populations."

Prokaryotes, whose initial cell has additional or transformed genetic material, reproduce through asexual reproduction but may, in lateral gene transfer, display processes such as bacterial conjugation, transformation and transduction, which are similar to sexual reproduction although they do not lead to reproduction.

Humans usually produce a single oﬀspring at a time. Te mother's body is prepared for birth by hormones produced by the pituitary gland, the ovary and the placenta. Te total gestation period from fertilization to birth is normally about 38 weeks (birth usually occurring 40 weeks after the last menstrual period). Te normal process of childbirth takes several hours and has three stages. Te frst stage starts with a series of involuntary contractions of the muscular walls of the uterus and gradual dilation of the cervix. Te active phase of the frst stage starts when the cervix is dilated more than about 4 cm in diameter and is when the contractions become stronger and regular. Te head (or the buttocks in a breech birth) of the baby is pushed against the cervix, which gradually dilates until is fully dilated at 10 cm diameter. At some time, the amniotic sac bursts and the amniotic fuid escapes (also known as rupture of membranes or breaking the water). In stage two, starting when the cervix is fully dilated, strong contractions of the uterus and active pushing by the mother expels the baby out through the vagina, which during this stage of labour is called a birth canal as this passage contains a baby, and the baby is born with umbilical cord attached. In stage three, which begins after the birth of the baby, further contractions expel the placenta, amniotic sac, and the remaining portion of the umbilical cord usually within a few minutes.

Enormous changes take place in the newborn's circulation to enable breathing in air. In the uterus, the unborn baby is dependent on circulation of blood through the placenta for sustenance including gaseous exchange and the unborn baby's blood bypasses the lungs by fowing though the foramen ovale, which is a hole in the septum dividing the right atrium and left atrium. After birth the umbilical cord is clamped and cut, the baby starts to breathe air, and blood from the right ventricle starts to fow to the lungs for gaseous exchange and oxygenated blood returns to the left atrium, which is pumped into the left ventricle, and then pumped into the main arterial system. As result of these changes, the blood pressure in the left atrium exceeds the pressure in the right atrium, and this pressure diﬀerence forces the foramen ovale to close separating the left and right sides of the heart. Te umbilical vein, umbilical arteries, ductus venosus and ductus arteriosus are not needed for life in air and in time these vessels become ligaments (embryonic remnants).

A fetus is a stage in the prenatal development of viviparous organisms. In human development, a fetus or foetus (/ˈfːtəs/; plural fetuses or foetuses) is a prenatal human between the embryonic state and birth. Te fetal stage of human development tends to be taken as beginning at the gestational age of eleven weeks, i.e. nine weeks after fertilization. In biological terms, however, prenatal development is a continuum, with no clear defning feature distinguishing an embryo from a fetus. A fetus is also characterized by the presence of all the major body organs, though they will not yet be fully developed and functional and some not yet situated in their fnal anatomical location.

In humans, the fetal stage commences at the beginning of the ninth week. At the start of the fetal stage, the fetus is typically about 30 millimetres (1.2 in) in length from crown to rump, and weighs about 8 grams. Te head makes up nearly half of the fetus' size. Breathing-like movement of the fetus is necessary for stimulation of lung development, rather than for obtaining oxygen. Te heart, hands, feet, brain and other organs are present, but are only at the beginning of development and have minimal operation. Te genitalia of the fetus starts to form and placenta becomes fully functional during week 9.

At this point in development, uncontrolled movements and twitches occur as muscles, the brain, and pathways begin to develop.

17 to 25 Weeks (41⁄4 to 61⁄4 months) A woman pregnant for the frst time (primiparous), typically feels fetal movements at about 21 weeks, whereas a woman who has given birth at least once (multiparous), will typically feel movements by 20 weeks. By the end of the ffth month, the fetus is about 20 cm (8 inches) long.

26 to 38 Weeks (61⁄2 to 91⁄2 months)

Te amount of body fat rapidly increases. Lungs are not fully mature. Talamic brain connections, which mediate sensory input, form. Bones are fully developed, but are still soft and pliable. Iron, calcium, and phosphorus become more abundant. Fingernails reach the end of the fngertips. Te lanugo, or fne hair, begins to disappear, until it is gone except on the upper arms and shoulders. Small breast buds are present on both sexes. Head hair becomes coarse and thicker. Birth is imminent and occurs around the 38th week after fertilization. Te fetus is considered full-term between weeks 36 and 40, when it is

95 suﬃciently developed for life outside the uterus. It may be 48 to 53 cm (19 to 21 inches) in length, when born. Control of movement is limited at birth, and purposeful voluntary movements develop all the way until puberty.

Variation in growth Tere is much variation in the growth of the human fetus. When fetal size is less than expected, that condition is known as intrauterine growth restriction (IUGR) also called fetal growth restriction (FGR); factors aﬀecting fetal growth can be maternal, placental, or fetal.

Maternal factors include maternal weight, body mass index, nutritional state, emotional stress, toxin exposure (including tobacco, alcohol, heroin, and other drugs which can also harm the fetus in other ways), and uterine blood fow.

Placental factors include size, microstructure (densities and architecture), umbilical blood fow, transporters and binding proteins, nutrient utilization and nutrient production.

Fetal factors include the fetus genome, nutrient production, and hormone output. Also, female fetuses tend to weigh less than males, at full term.

Fetal growth is often classifed as follows: small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA).[22] SGA can result in low birth weight, although premature birth can also result in low birth weight. Low birth weight increases risk for perinatal mortality (death shortly after birth), asphyxia, hypothermia, polycythemia, hypocalcemia, immune dysfunction, neurologic abnormalities, and other long-term health problems. SGA may be associated with growth delay, or it may instead be associated with absolute stunting of growth.

Viability refers to a point in fetal development at which the fetus may survive outside the womb. Te lower limit of viability is approximately 5-3/4 months gestational age and is usually later.

Tere is no sharp limit of development, age, or weight at which a fetus automatically becomes viable. According to data from 2003–05, survival rates are 20–35% for babies born at 23 weeks of gestation (5-3/4 months); 50–70% at 24-25 weeks (6 - 6-1/4 months); and >90% at 26-27 weeks (6-1/2 - 6-3/4 months) and over. [25] It is rare for a baby weighing less than 1.1 pounds (0.50 kg) to survive.

When such premature babies are born, the main causes of perinatal mortality are that the respiratory system and the central nervous system are not completely diﬀerentiated. If given expert postnatal care, some fetuses weighing less than 1.1 pounds (0.50 kg) may survive, and are referred to as extremely low birth weight or immature infants.

Preterm birth is the most common cause of perinatal mortality, causing almost 30 percent of neonatal deaths. At an occurrence rate of 5% to 18% of all deliveries, it is also more common than postmature birth, which occurs in 3% to 12% of pregnancies.

Fetal pain, its existence and its implications are debated politically and academically. According to the conclusions of a review published in 2005, "Evidence regarding the capacity for fetal pain is limited but indicates that fetal perception of pain is unlikely before the third trimester.” However, developmental neurobiologists argue that the establishment of thalamocortical connections (at about 6-1/2 months) is an essential event with regard to fetal perception of pain. Nevertheless, the perception of pain involves sensory, emotional and cognitive factors and it is "impossible to know" when pain is experienced, even if it is known when thalamocortical connections are established. Some authors argue that fetal pain is possible from the second half of pregnancy: “Te available scientifc evidence makes it possible, even probable, that fetal pain perception occurs well before late gestation” wrote KJS Anand in the journal of the IASP.

Whether a fetus has the ability to feel pain and suﬀering is part of the abortion debate. In the United States, for example, pro-life advocates have proposed legislation that would require providers of abortions to inform women that their fetuses may feel pain during the procedure and that would require each woman to accept or decline anesthesia for the fetus.

Te heart and blood vessels which form the circulatory system, form relatively early during embryonic development, but continue to grow and develop in complexity in the growing fetus. A functional circulatory system is a biological necessity, since mammalian tissues can not grow more than a few cell layers thick without an active blood supply. Te prenatal circulation of blood is diﬀerent than the postnatal circulation, mainly because the lungs are not in use. Te fetus obtains oxygen and nutrients from the mother through the placenta and the umbilical cord.

Blood from the placenta is carried to the fetus by the umbilical vein. About half of this enters the fetal ductus venosus and is carried to the inferior vena cava, while the other half enters the liver proper from the inferior border of the liver. Te branch

96 of the umbilical vein that supplies the right lobe of the liver frst joins with the portal vein. Te blood then moves to the right atrium of the heart. In the fetus, there is an opening between the right and left atrium (the foramen ovale), and most of the blood fows from the right into the left atrium, thus bypassing pulmonary circulation. Te majority of blood fow is into the left ventricle from where it is pumped through the aorta into the body. Some of the blood moves from the aorta through the internal iliac arteries to the umbilical arteries, and re-enters the placenta, where carbon dioxide and other waste products from the fetus are taken up and enter the woman's circulation.

Some of the blood from the right atrium does not enter the left atrium, but enters the right ventricle and is pumped into the pulmonary artery. In the fetus, there is a special connection between the pulmonary artery and the aorta, called the ductus arteriosus, which directs most of this blood away from the lungs (which aren't being used for respiration at this point as the fetus is suspended in amniotic fuid).

Breathing (or respiration, or ventilation) is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly by bringing in oxygen and fushing out carbon dioxide.

All aerobic creatures need oxygen for cellular respiration, which uses the oxygen to break down foods for energy and produces carbon dioxide as a waste product. Breathing, or "external respiration", brings air into the lungs where gas exchange takes place in the alveoli through diﬀusion. Te body's circulatory system transports these gasses to and from the cells, where "cellular respiration" takes place.

Te breathing of all vertebrates with lungs consists of repetitive cycles of inhalation and exhalation through a highly branched system of tubes or airways which lead from the nose to the alveoli. Te number of respiratory cycles per minute is the breathing or respiratory rate, and is one of the four primary vital signs of life. Under normal conditions the breathing depth and rate is automatically, and unconsciously, controlled by several homeostatic mechanisms which keep the partial pressures of carbon dioxide and oxygen in the arterial blood constant. Keeping the partial pressure of carbon dioxide in the arterial blood unchanged under a wide variety of physiological circumstances, contributes signifcantly to tight control of the pH of the extracellular fuids (ECF). Over-breathing (hyperventilation) and under-breathing (hypoventilation), which decrease and increase the arterial partial pressure of carbon dioxide respectively, cause a rise in the pH of ECF in the frst case, and a lowering of the pH in the second. Both cause distressing symptoms.

Breathing has other important functions. It provides a mechanism for speech, laughter and similar expressions of the emotions. It is also used for refexes such as yawning, coughing and sneezing. Animals that cannot thermoregulate by perspiration, because they lack suﬃcient sweat glands, may lose heat by evaporation through panting.

In biology, tissue is a cellular organizational level between cells and a complete organ. A tissue is an ensemble of similar cells and their extracellular matrix from the same origin that together carry out a specifc function. Organs are then formed by the functional grouping together of multiple tissues.

Te English word is derived from the French tissu, meaning something that is woven, from the verb tisser, "to weave".

Te study of human and animal tissues is known as histology or, in connection with disease, histopathology. For plants, the discipline is called plant anatomy. Te classical tools for studying tissues are the paraﬃn block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. In the last couple of decades, developments in electron microscopy, immunofuorescence, and the use of frozen tissue sections have enhanced the detail that can be observed in tissues. With these tools, the classical appearances of tissues can be examined in health and disease, enabling considerable refnement of medical diagnosis and prognosis.

Te immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue. In many species, the immune system can be classifed into subsystems, such as the innate immune system versus the adaptive immune system, or humoral immunity versus cell-mediated immunity. In humans, the blood–brain barrier, blood–cerebrospinal fuid barrier, and similar fuid– brain barriers separate the peripheral immune system from the neuroimmune system, which protects the brain.

Pathogens can rapidly evolve and adapt, and thereby avoid detection and neutralization by the immune system; however, multiple defense mechanisms have also evolved to recognize and neutralize pathogens. Even simple unicellular organisms such as bacteria possess a rudimentary immune system in the form of enzymes that protect against bacteriophage infections. Other basic immune mechanisms evolved in ancient eukaryotes and remain in their modern descendants, such as plants and invertebrates. Tese mechanisms include phagocytosis, antimicrobial peptides called defensins, and the complement system. Jawed vertebrates, including humans, have even more sophisticated defense mechanisms, including the ability to adapt over

97 time to recognize specifc pathogens more eﬃciently. Adaptive (or acquired) immunity creates immunological memory after an initial response to a specifc pathogen, leading to an enhanced response to subsequent encounters with that same pathogen. Tis process of acquired immunity is the basis of vaccination.

Disorders of the immune system can result in autoimmune diseases, infammatory diseases and cancer. Immunodefciency occurs when the immune system is less active than normal, resulting in recurring and life-threatening infections. In humans, immunodefciency can either be the result of a genetic disease such as severe combined immunodefciency, acquired conditions such as HIV/AIDS, or the use of immunosuppressive medication. In contrast, autoimmunity results from a hyperactive immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include Hashimoto's thyroiditis, rheumatoid arthritis, diabetes mellitus type 1, and systemic lupus erythematosus. Immunology covers the study of all aspects of the immune system.

Anatomy (Greek anatomē, “dissection”) is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science dealing with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated over immediate (embryology) and long (evolution) timescales. Human anatomy is one of the basic essential sciences of medicine. Anatomy and physiology, which study (respectively) the structure and function of organisms and their parts, make a natural pair of related disciplines, and they are often studied together.

Te discipline of anatomy is divided into macroscopic and microscopic anatomy. Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of superfcial anatomy. Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology, and also in the study of cells.

Te history of anatomy is characterized by a progressive understanding of the functions of the organs and structures of the human body. Methods have also improved dramatically, advancing from the examination of animals by dissection of carcasses and cadavers (corpses) to 20th century medical imaging techniques including X-ray, ultrasound, and magnetic resonance imaging.

In biology, an organ or viscus is a collection of tissues joined in a structural unit to serve a common function. In anatomy, a viscus is an internal organ, and viscera is the plural form.

Organs are composed of main tissue, parenchyma, and "sporadic" tissues, stroma. Te main tissue is that which is unique for the specifc organ, such as the myocardium, the main tissue of the heart, while sporadic tissues include the nerves, blood vessels, and connective tissues. Te main tissues that make up an organ tend to have common embryologic origins, such as arising from the same germ layer. Functionally related organs often cooperate to form whole organ systems. Organs exist in all higher biological organisms, in particular they are not restricted to animals, but can also be identifed in plants. In single- cell organisms like bacteria, the functional analogue of an organ is called organelle.

A hollow organ is a visceral organ that forms a hollow tube or pouch, such as the stomach, intestine, or bladder. 79 organs have been scientifcally validated in the human body: men have 72 organs, women have 76 and hermaphrodites (intersex) can have 79.

Two or more organs working together in the execution of a specifc body function form an organ system, also called a biological system or body system. Te functions of organ systems often share signifcant overlap. For instance, the nervous and endocrine system both operate via a shared organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system. Te same is true for the musculoskeletal system because of the relationship between the muscular and skeletal systems.

Mammals such as humans have a variety of organ systems. Tese specifc systems are also widely studied in human anatomy. Te English word "organ" derives from the Latin organum, meaning "instrument", itself from the Greek word ὄργανον, órganon ("implement; musical instrument; organ of the body"). Te Greek word is related to ἔργον, érgon ("work").Te viscera, when removed from a butchered animal, are known collectively as oﬀal. Internal organs are also informally known as "guts" (which may also refer to the gastrointestinal tract), or more formally, "innards".

98 Aristotle used the word frequently in his philosophy, both to describe the organs of plants or animals (e.g. the roots of a tree, the heart or liver of an animal), and to describe more abstract "parts" of an interconnected whole (e.g. his philosophical works, taken as a whole, are referred to as the "organon").

Te English word "organism" is a neologism coined in the 17th century, probably formed from the verb to organize. At frst the word referred to an organization or social system. Te meaning of a living animal or plant is frst recorded in 1842. Plant organs are made from tissue built up from diﬀerent types of tissue. When there are three or more organs it is called an organ system.

Te adjective visceral, also splanchnic, is used for anything pertaining to the internal organs. Historically, viscera of animals were examined by Roman pagan priests like the haruspices or the augurs in order to divine the future by their shape, dimensions or other factors. Tis practice remains an important ritual in some remote, tribal societies.

Te term "visceral" is contrasted with the term "parietal", meaning "of or relating to the wall of a body part, organ or cavity”. Te two terms are often used in describing a membrane or piece of connective tissue, referring to the opposing sides. the Body

Human skeleton

Te human skeleton is the internal framework of the body. It is composed of around 270 bones at birth – this total decreases to around 206 bones by adulthood after some bones get fused together. Te bone mass in the skeleton reaches maximum density around age 21. Te human skeleton can be divided into the axial skeleton and the appendicular skeleton. Te axial skeleton is formed by the vertebral column, the rib cage, the skull and other associated bones. Te appendicular skeleton, which is attached to the axial skeleton, is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs.

Te human skeleton performs six major functions; support, movement, protection, production of blood cells, storage of minerals, and endocrine regulation.

Te human skeleton is not as sexually dimorphic as that of many other primate species, but subtle diﬀerences between sexes in the morphology of the skull, dentition, long bones, and pelvis exist. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population. Te human female pelvis is also diﬀerent from that of males in order to facilitate childbirth. Unlike most primates, human males do not have penile bones.

Joints

A joint or articulation (or articular surface) is the connection made between bones in the body which link the skeletal system into a functional whole. Tey are constructed to allow for diﬀerent degrees and types of movement. Some joints, such as the knee, elbow, and shoulder, are self-lubricating, almost frictionless, and are able to withstand compression and maintain heavy loads while still executing smooth and precise movements. Other joints such as sutures between the bones of the skull permit very little movement (only during birth) in order to protect the brain and the sense organs. Te connection between a tooth and the jawbone is also called a joint, and is described as a fbrous joint known as a gomphosis. Joints are classifed both structurally and functionally.

Ligaments

A ligament is the fbrous connective tissue that connects bones to other bones. It is also known as articular ligament, articular larua, fbrous ligament, or true ligament. Other ligaments in the body include the:

Peritoneal ligament: a fold of peritoneum or other membranes. Fetal remnant ligament: the remnants of a fetal tubular structure. Periodontal ligament: a group of fbers that attach the cementum of teeth to the surrounding alveolar bone. Ligaments are similar to tendons and fasciae as they are all made of connective tissue. Te diﬀerences in them are in the connections that they make: ligaments connect one bone to another bone, tendons connect muscle to bone, and fasciae connect muscles to other muscles. Tese are all found in the skeletal system of the human body. Ligaments cannot usually be regenerated naturally; however, there are periodontal ligament stem cells located near the periodontal ligament which are involved in the adult regeneration of periodontal ligament.

Muscular system

99 Muscle is a soft tissue found in most animals. Muscle cells contain protein flaments of actin and myosin that slide past one another, producing a contraction that changes both the length and the shape of the cell. Muscles function to produce force and motion. Tey are primarily responsible for maintaining and changing posture, locomotion, as well as movement of internal organs, such as the contraction of the heart and the movement of food through the digestive system via peristalsis.

Muscle tissues are derived from the mesodermal layer of embryonic germ cells in a process known as myogenesis. Tere are three types of muscle, skeletal or striated, cardiac, and smooth. Muscle action can be classifed as being either voluntary or involuntary. Cardiac and smooth muscles contract without conscious thought and are termed involuntary, whereas the skeletal muscles contract upon command. Skeletal muscles in turn can be divided into fast and slow twitch fbers.

Muscles are predominantly powered by the oxidation of fats and carbohydrates, but anaerobic chemical reactions are also used, particularly by fast twitch fbers. Tese chemical reactions produce adenosine triphosphate (ATP) molecules that are used to power the movement of the myosin heads.

Te term muscle is derived from the Latin musculus meaning "little mouse" perhaps because of the shape of certain muscles or because contracting muscles look like mice moving under the skin.

Tendons

A tendon or sinew is a tough band of fbrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments; both are made of collagen. Ligaments join one bone to another bone, while tendons connect muscle to bone.

Digestive system

Te human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). In this system, the process of digestion has many stages, the frst of which starts in the mouth. Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body.

Chewing, in which food is mixed with saliva begins the process of digestion. Tis produces a bolus which can be swallowed down the esophagus and into the stomach. Here it is mixed with gastric juice until it passes into the duodenum where it is mixed with a number of enzymes produced by the pancreas. Saliva also contains a catalytic enzyme called amylase which starts to act on food in the mouth. Another digestive enzyme called lingual lipase is secreted by some of the lingual papillae on the tongue and also from serous glands in the main salivary glands. Digestion is helped by the mastication of food by the teeth and also by the muscular actions of peristalsis and segmentation contractions. Gastric juice in the stomach is essential for the continuation of digestion as is the production of mucus in the stomach.

Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues along the wall of the stomach and the rest of the gastrointestinal tract. Tis initially results in the production of chyme which when fully broken down in the small intestine is absorbed as chyle into the lymphatic system. Most of the digestion of food takes place in the small intestine. Water and some minerals are reabsorbed back into the blood in the colon of the large intestine. Te waste products of digestion (feces) are defecated from the anus via the rectum.

Digestive system Mouth

In animal anatomy, the mouth, also known as the oral cavity, buccal cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on the outside by the lips and inside by the pharynx and containing in higher vertebrates the tongue and teeth. Tis cavity is also known as the buccal cavity, from the Latin bucca ("cheek").

Some animal phyla, including vertebrates, have a complete digestive system, with a mouth at one end and an anus at the other. Which end forms frst in ontogeny is a criterion used to classify animals into protostome and deuterostome. Teeth

A tooth (plural teeth) is a hard, calcifed structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. Te roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness. Te cellular tissues that ultimately become teeth originate from the embryonic germ layer, the ectoderm.

100 Te general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. Te teeth of mammals have deep roots, and this pattern is also found in some fsh, and in crocodilians. In most teleost fsh, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous fsh, such as sharks, the teeth are attached by tough ligaments to the hoops of cartilage that form the jaw.

Some animals develop only one set of teeth (monophyodont) while others develop many sets (polyphyodont). Sharks, for example, grow a new set of teeth every two weeks to replace worn teeth. Rodent incisors grow and wear away continually through gnawing, which helps maintain relatively constant length. Te industry of the beaver is due in part to this qualifcation. Many rodents such as voles and guinea pigs, but not mice, as well as leporidae like rabbits, have continuously growing molars in addition to incisors.

Teeth are not always attached to the jaw, as they are in mammals. In many reptiles and fsh, teeth are attached to the palate or to the foor of the mouth, forming additional rows inside those on the jaws proper. Some teleosts even have teeth in the pharynx. While not true teeth in the usual sense, the dermal denticles of sharks are almost identical in structure and are likely to have the same evolutionary origin. Indeed, teeth appear to have frst evolved in sharks, and are not found in the more primitive jawless fsh – while lampreys do have tooth-like structures on the tongue, these are in fact, composed of keratin, not of dentine or enamel, and bear no relationship to true teeth. Tough "modern" teeth-like structures with dentine and enamel have been found in late conodonts, they are now supposed to have evolved independently of later vertebrates' teeth.

Living amphibians typically have small teeth, or none at all, since they commonly feed only on soft foods. In reptiles, teeth are generally simple and conical in shape, although there is some variation between species, most notably the venom- injecting fangs of snakes. Te pattern of incisors, canines, premolars and molars is found only in mammals, and to varying extents, in their evolutionary ancestors. Te numbers of these types of teeth vary greatly between species; zoologists use a standardised dental formula to describe the precise pattern in any given group.

Tongue

Te tongue is a muscular organ in the mouth of most vertebrates that manipulates food for mastication, and is used in the act of swallowing. It is of importance in the digestive system and is the primary organ of taste in the gustatory system. Te tongue's upper surface (dorsum) is covered by taste buds housed in numerous lingual papillae. It is sensitive and kept moist by saliva, and is richly supplied with nerves and blood vessels. Te tongue also serves as a natural means of cleaning the teeth. A major function of the tongue is the enabling of speech in humans and vocalization in other animals.

Te human tongue is divided into two parts, an oral part at the front and a pharyngeal part at the back. Te left and right sides are also separated along most of its length by a vertical section of fbrous tissue (the lingual septum) that results in a groove, the median sulcus on the tongue's surface.

Tere are two groups of muscles of the tongue. Te four intrinsic muscles alter the shape of the tongue and are not attached to bone. Te four paired extrinsic muscles change the position of the tongue and are anchored to bone.

Salivary glands

Te salivary glands in mammals are exocrine glands, glands with ducts, that produce saliva, which is composed of several components including amylase, a digestive enzyme that breaks down starch into maltose and glucose. In humans and some other mammals the secretion is alpha-amylase, also known as ptyalin.

Parotid glands

Te parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. Tey are the largest of the salivary glands. Each parotid is wrapped around the mandibular ramus, and secretes serous saliva through the parotid duct into the mouth, to facilitate mastication and swallowing and to begin the digestion of starches.

Te word parotid (paraotic) literally means "beside the ear".

Submandibular glands

101 Te paired submandibular glands (historically known as submaxillary glands) are major salivary glands located beneath the foor of the mouth. Tey each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as the parotid secretion rises to 50%.

Sublingual glands

Te paired sublingual glands are major salivary glands in the mouth. Tey are the smallest, most diﬀuse, and the only unencapsulated major salivary glands. Tey provide only 3-5% of the total salivary volume.

Pharynx

Te pharynx (plural: pharynges) is the part of the throat that is behind the mouth and nasal cavity and above the esophagus and the larynx, or the tubes going down to the stomach and the lungs. Te pharynx is an organ found in vertebrates and invertebrates, though the structure is not universally the same across all of those species.

In humans the pharynx is part of the digestive system and also of the conducting zone of the respiratory system. (Te conducting zone also includes the nostrils of the nose, larynx, trachea, bronchi, and bronchioles, and their function is to flter, warm, and moisten air and conduct it into the lungs.) Te pharynx makes up the part of the throat situated immediately behind the nasal cavity, behind the mouth and above the esophagus and larynx. Te human pharynx is conventionally divided into three sections: the nasopharynx, the oropharynx and the laryngopharynx. It is also important in vocalization.

In humans there are two sets of pharyngeal muscles that form the pharynx, determining the shape of its lumen. Tese are arranged as an inner layer of longitudinal muscles and an outer circular layer.

Esophagus

Te esophagus (American English) or oesophagus (British English) (/ɪˈsɒfəɡəs/), commonly known as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. Te esophagus is a fbromuscular tube, about 25 centimetres long in adults, which travels behind the trachea and heart, passes through the diaphragm and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. Te word esophagus is the Greek word οἰσοφάγος oisophagos, meaning "gullet".

Te wall of the esophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fbers between layers of fbrous tissue, and an outer layer of connective tissue. Te mucosa is a stratifed squamous epithelium of around three layers of squamous cells, which contrasts to the single layer of columnar cells of the stomach. Te transition between these two types of epithelium is visible as a zig-zag line. Most of the muscle is smooth muscle although striated muscle predominates in its upper third. It has two muscular rings or sphincters in its wall, one at the top and one at the bottom. Te lower sphincter helps to prevent refux of acidic stomach content. Te esophagus has a rich blood supply and venous drainage. Its smooth muscle is innervated by involuntary nerves (sympathetic nerves via the sympathetic trunk and parasympathetic nerves via the vagus nerve) and in addition voluntary nerves (lower motor neurons) which are carried in the vagus nerve to innervate its striated muscle.

Te esophagus may be affected by gastric refux, cancer, prominent dilated blood vessels called varices that can bleed heavily, tears, constrictions, and disorders of motility. Diseases may cause difficulty swallowing (dysphagia), painful swallowing (odynophagia), chest pain, or cause no symptoms at all. Clinical investigations include X-rays when swallowing barium, endoscopy, and CT scans. Surgically, the esophagus is very difficult to access.

Stomach

Te stomach (from ancient Greek στόμαχος, stomachos, stoma means mouth) is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. Te stomach has a dilated structure and functions as a vital digestive organ. In the digestive system the stomach is involved in the second phase of digestion, following mastication (chewing).

In humans and many other animals, the stomach is located between the oesophagus and the small intestine. It secretes digestive enzymes and gastric acid to aid in food digestion. Te pyloric sphincter controls the passage of partially digested

102 food (chyme) from the stomach into the duodenum where peristalsis takes over to move this through the rest of the intestines.

Small intestine

Te small intestine or small bowel is the part of the gastrointestinal tract between the stomach and the large intestine, and is where most of the end absorption of food takes place. Te small intestine has three distinct regions – the duodenum, jejunum, and ileum. Te duodenum is the shortest part of the small intestine and is where preparation for absorption begins. It also receives bile and pancreatic juice through the pancreatic duct, controlled by the sphincter of Oddi. Te primary function of the small intestine is the absorption of nutrients and minerals from food, using small fnger-like protrusions called villi.

Duodenum

Te duodenum is the frst section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fsh, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine may be used instead of duodenum. In mammals the duodenum may be the principal site for iron absorption.

Te duodenum precedes the jejunum and ileum and is the shortest part of the small intestine .

In humans, the duodenum is a hollow jointed tube about 25–38 cm (10–15 inches) long connecting the stomach to the jejunum. It begins with the duodenal bulb and ends at the suspensory muscle of duodenum. It can be divided into four parts.

Jejunum

Te jejunum (/dʒɪˈdʒuːnəm/) is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds.

Te jejunum lies between the duodenum and the ileum. Te jejunum is considered to begin at the attachment of the suspensory muscle of the duodenum to the duodenum, a location called the duodenojejunal fexure.Te division between the jejunum and ileum is not anatomically distinct.In adult humans, the small intestine is usually 6-7m long, about two- ffths of which (2.5 m) is the jejunum.

Ileum

Te ileum /ˈɪliəm/ is the fnal section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fsh, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.

Te ileum follows the duodenum and jejunum and is separated from the cecum by the ileocecal valve (ICV). In humans, the ileum is about 2–4 m long, and the pH is usually between 7 and 8 (neutral or slightly alkaline).

Ileum is derived from the Greek word eilein, meaning "to twist up tightly." Large intestine

Te large intestine, also known as the large bowel or colon, is the last part of the gastrointestinal tract and of the digestive system in vertebrates. Water is absorbed here and the remaining waste material is stored as feces before being removed by defecation.

Most sources defne the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal.

In humans, the large intestine begins in the right iliac region of the pelvis, just at or below the waist, where it is joined to the end of the small intestine at the cecum, via the ileocecal valve. It then continues as the colon ascending the abdomen, across the width of the abdominal cavity as the transverse colon, and then descending to the rectum and its endpoint at the anal canal. Overall, in humans, the large intestine is about 1.5 metres (5 ft) long, which is about one-ffth of the whole length of the gastrointestinal tract.

Liver

103 Te liver, an organ only found in vertebrates, detoxifes various metabolites, synthesizes proteins, and produces biochemicals necessary for digestion. In humans, it is located in the right upper quadrant of the abdomen, below the diaphragm. Its other roles in metabolism include the regulation of glycogen storage, decomposition of red blood cells and the production of hormones.

Te liver is an accessory digestive gland that produces bile, an alkaline compound which helps the breakdown of fat. Bile aids in digestion via the emulsifcation of lipids. Te gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver.Te liver's highly specialized tissue consisting of mostly hepatocytes regulates a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex molecules, many of which are necessary for normal vital functions. Estimates regarding the organ's total number of functions vary, but textbooks generally cite it being around 500.

Terminology related to the liver often starts in hepat- from ἡπατο-, the Greek word for liver.

Tere is currently no way to compensate for the absence of liver function in the long term, although liver dialysis techniques can be used in the short term. Artifcial livers are yet to be developed to promote long-term replacement in the absence of the liver. As of 2017, liver transplantation is the only option for complete liver failure.

Gallbladder

In vertebrates, the gallbladder is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear- shaped gallbladder lies beneath the liver, although the structure and position of the gallbladder can vary signifcantly among animal species. It receives and stores bile, produced by the liver, via the common hepatic duct, and releases it via the common bile duct into the duodenum, where the bile helps in the digestion of fats.

Te gallbladder can be aﬀected by gallstones, formed by material that cannot be dissolved – usually cholesterol or bilirubin, a product of haemoglobin breakdown. Tese may cause signifcant pain, particularly in the right upper corner of the abdomen, and are often treated with removal of the gallbladder called a cholecystectomy. Cholecystitis, infammation of the gullible

Mesentery

Te mesentery is a continuous set of tissues now recognised as an organ and entered as such in the 2017 edition of Gray's anatomy. Te mesentery is a set of tissues which is formed by the double fold of peritoneum that attaches the intestines to the wall of the abdomen. It has been proposed for reclassifcation as an organ due to research fndings at the University of Limerick in the 2010s.

Conventional teaching had described the mesocolon as a fragmented structure with all the named parts—the ascending, transverse, descending, and sigmoid mesocolons, mesoappendix, and mesorectum as separately terminating their insertion into the posterior abdominal wall.

In 2012, following detailed microscopic and electron microscopic examinations, the mesocolon was shown to be a single, continuous structure that commenced from the duodenojejunal fexure and extended to the level of the distal mesorectum. Tis simpler concept has enabled substantial advances to be made in diﬀerent aspects of surgery on the colon and rectum. It has also had implications for sciences related to surgery, anatomy, and development.

Pancreas

Te pancreas /ˈpæŋkriəs/ is a glandular organ in the digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity behind the stomach. It is an endocrine gland producing several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide, all of which circulate in the blood. Te pancreas is also a digestive organ, secreting pancreatic juice containing bicarbonate to neutralize acidity of chyme moving in from the stomach, as well as digestive enzymes that assist digestion and absorption of nutrients in the small intestine. Tese enzymes help to further break down the carbohydrates, proteins, and lipids in the chyme. Te pancreas is known as a mixed gland.

Respiratory system

Te respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specifc organs and structures used for gas exchange in animals and plants. Te anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the 104 respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds. Tese microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. Tese air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. Tese enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.

In most fsh, and a number of other aquatic animals (both vertebrates and invertebrates) the respiratory system consists of gills, which are either partially or completely external organs, bathed in the watery environment. Tis water fows over the gills by a variety of active or passive means. Gas exchange takes place in the gills which consist of thin or very fat flaments and lammelae which expose a very large surface area of highly vascularized tissue to the water.

Other animals, such as insects, have respiratory systems with very simple anatomical features, and in amphibians even the skin plays a vital role in gas exchange. Plants also have respiratory systems but the directionality of gas exchange can be opposite to that in animals. Te respiratory system in plants includes anatomical features such as stomata, that are found in various parts of the plant.

Nasal cavity

Te nasal cavity (nasal fossa, or nasal passage) is a large air flled space above and behind the nose in the middle of the face. Each cavity is the continuation of one of the two nostrils.

A nostril (or naris /ˈneɪrɪs/, plural nares /ˈneɪriːz/) is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation. Fish do not breathe through their noses, but they do have two small holes used for smelling, which may, indeed, be called nostrils.

Te Procellariiformes are distinguished from other birds by having tubular extensions of their nostrils. In humans, the nasal cycle is the normal ultradian cycle of each nostril's blood vessels becoming engorged in swelling, then shrinking.

Te nostrils are separated by the septum. Te septum can sometimes be deviated, causing one nostril to appear larger than the other. With extreme damage to the septum and columella, the two nostrils are no longer separated and form a single larger external opening.

Like other tetrapods, humans have two external nostrils (anterior nares) and two additional nostrils at the back of the nasal cavity, inside the head (posterior nares, posterior nasal apertures or choanae). Each choana contains approximately 1000 strands of nasal hair. Tey also connect the nose to the throat (the nasopharynx), aiding in respiration. Tough all four nostrils were on the outside the head of our fsh ancestors, the nostrils for outgoing water (excurrent nostrils) migrated to the inside of the mouth, as evidenced by the discovery of Kenichthys campbelli, a 395-million-year-old fossilized fsh which shows this migration in progress. It has two nostrils between its front teeth, similar to human embryos at an early stage. If these fail to join up, the result is a cleft palate.

It is possible for humans to smell diﬀerent olfactory inputs in the two nostrils and experience a perceptual rivalry akin to that of binocular rivalry when there are two diﬀerent inputs to the two eyes.

Pharynx

Larynx

Te larynx, commonly called the voice box, is an organ in the top of the neck of tetrapods involved in breathing, producing sound, and protecting the trachea against food aspiration. Te larynx houses the vocal cords, and manipulates pitch and volume, which is essential for phonation. It is situated just below where the tract of the pharynx splits into the trachea and the esophagus. Te word larynx (plural larynges) comes from a similar Ancient Greek word.

Trachea

Te trachea, colloquially called the windpipe, is a cartilaginous tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. Te trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea the cricoid cartilage attaches it to the larynx. Tis is the only complete tracheal ring, the others being incomplete rings of reinforcing cartilage. Te trachealis muscle joins the ends of the rings and these are joined vertically by bands of fbrous connective tissue – the annular ligaments of trachea. Te epiglottis closes the opening to the larynx during swallowing.

Te trachea develops in the second month of development. It is lined with an epithelium that has goblet cells which produce protective mucins. An infammatory condition, also involving the larynx and bronchi, called croup can result in a barking cough. A tracheotomy is often performed for ventilation in surgical operations where needed. Intubation is also carried out for the same reason by the inserting of a tube into the trachea. From 2008, operations have experimentally transplanted a windpipe grown by stem cells, and synthetic windpipes; their success is, however, doubtful.

Bronchi

A bronchus, is a passage of airway in the respiratory tract that conducts air into the lungs. Te frst bronchi to branch from the trachea are the right main bronchus and the left main bronchus. Tese are the widest and enter the lungs at each hilum, where they branch into narrower secondary bronchi known as lobar bronchi, and these branch into narrower tertiary bronchi known as segmental bronchi. Further divisions of the segmental bronchi are known as 4th order, 5th order, and 6th order segmental bronchi, or grouped together as subsegmental bronchi. Te bronchi when too narrow to be supported by cartilage are known as bronchioles. No gas exchange takes place in the bronchi.

Lungs

Te lungs are the primary organs of the respiratory system in humans and many other animals including a few fsh and some snails. In mammals and most other vertebrates, two lungs are located near the backbone on either side of the heart. Teir function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their different muscles to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the main muscle of respiration that drives breathing is the diaphragm. Te lungs also provide airfow that makes vocal sounds including human speech possible.

Humans have two lungs, a right lung and a left lung. Tey are situated within the thoracic cavity of the chest. Te right lung is bigger than the left, which shares space in the chest with the heart. Te lungs together weigh approximately 1.3 kilograms (2.9 lb), and the right is heavier. Te lungs are part of the lower respiratory tract that begins at the trachea and branches into the bronchi and bronchioles, and which receive air breathed in via the conducting zone. Te conducting zone ends at the terminal bronchioles. Tese divide into the respiratory bronchioles of the respiratory zone which divide into alveolar ducts that give rise to the microscopic alveoli, where gas exchange takes place. Together, the lungs contain approximately 2,400 kilometres (1,500 mi) of airways and 300 to 500 million alveoli. Each lung is enclosed within a pleural sac which allows the inner and outer walls to slide over each other whilst breathing takes place, without much friction. Tis sac also divides each lung into sections called lobes. Te right lung has three lobes and the left has two. Te lobes are further divided into bronchopulmonary segments and lobules. Te lungs have a unique blood supply, receiving deoxygenated blood from the heart in the pulmonary circulation for the purposes of receiving oxygen and releasing carbon dioxide, and a separate supply of oxygenated blood to the tissue of the lungs, in the bronchial circulation.

106 Te tissue of the lungs can be aﬀected by a number of diseases, including pneumonia and lung cancer. Chronic obstructive pulmonary disease includes chronic bronchitis and previously termed emphysema, can be related to smoking or exposure to harmful substances such as coal dust, asbestos fbres and crystalline silica dust. Diseases such as bronchitis can also aﬀect the respiratory tract. Medical terms related to the lung often begin with pulmo-, from the Latin pulmonarius (of the lungs) as in pulmonology, or with pneumo- (from Greek πνεύμων "lung") as in pneumonia.

In embryonic development, the lungs begin to develop as an outpouching of the foregut, a tube which goes on to form the upper part of the digestive system. When the lungs are formed the fetus is held in the fuid-flled amniotic sac and so they do not function to breathe. Blood is also diverted from the lungs through the ductus arteriosus. At birth however, air begins to pass through the lungs, and the diversionary duct closes, so that the lungs can begin to respire. Te lungs only fully develop in early childhood.

Diaphragm

In human anatomy, the thoracic diaphragm, or simply the diaphragm (Ancient Greek: διάφραγμα, translit. diáphragma, lit. 'partition'), is a sheet of internal skeletal muscle[2] that extends across the bottom of the thoracic cavity. Te diaphragm separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.

Te term diaphragm in anatomy can refer to other fat structures such as the urogenital diaphragm or pelvic diaphragm, but "the diaphragm" generally refers to the thoracic diaphragm. In humans, the diaphragm is slightly asymmetric—its right half is higher up (superior) to the left half, since the large liver rests beneath the right half of the diaphragm. Tere is also a theory that the diaphragm is lower on the other side due to the presence of the heart.

Other mammals have diaphragms, and other vertebrates such as amphibians and reptiles have diaphragm-like structures, but important details of the anatomy vary, such as the position of the lungs in the abdominal cavity.

Urinary system

Te urinary system, also known as the renal system, consists of the kidneys, ureters, bladder, and the urethra. Each kidney consists of functional units called nephrons. Te purpose of the renal system is to eliminate waste from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH. Te kidneys have an extensive blood supply via the renal arteries which leave the kidneys via the renal vein. Following fltration of blood and further processing, wastes (in the form of urine) exit the kidney via the ureters, tubes made of smooth muscle fbres that propel urine towards the urinary bladder, where it is stored and subsequently expelled from the body by urination (voiding). Te female and male urinary system are very similar, diﬀering only in the length of the urethra.

Urine is formed in the kidneys through a fltration of blood. Te urine is then passed through the ureters to the bladder, where it is stored. During urination, the urine is passed from the bladder through the urethra to the outside of the body.

800–2,000 milliliters (mL) of urine are normally produced every day in a healthy human. Tis amount varies according to fuid intake and kidney function. Kidneys

Te kidneys are two bean-shaped organs found on the left and right sides of the body in vertebrates. Tey are located at the back of the abdominal cavity in the retroperitoneal space. In adults they are about 11 centimetres (4.3 in) in length. Tey receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.

Te nephron is the structural and functional unit of the kidney. Each adult kidney contains around one million nephrons. Te nephron utilizes four processes to alter the blood plasma which fows to it: fltration, reabsorption, secretion, and excretion. Via one or more of these mechanisms, the kidney participates in the control of the volume of various body fuid compartments, fuid osmolality, acid-base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus: one-ffth of the blood volume that enters the kidneys is fltered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hydrogen, ammonium, potassium and uric acid. Te kidneys also carry out functions independent of the nephron. For example, they convert a precursor of vitamin D to its active form – calcitriol – and synthesize the hormones erythropoietin and renin.

107 Renal physiology is the study of kidney function. Nephrology is the medical specialty which addresses diseases of kidney function: these include chronic kidney disease, nephritic and nephrotic syndromes, acute kidney injury, and pyelonephritis. Urology addresses diseases of kidney (and urinary tract) anatomy: these include cancer, renal cysts, kidney stones and ureteral stones, and urinary tract obstruction.

Procedures used in the management of kidney disease include chemical and microscopic examination of the urine (urinalysis), measurement of kidney function by calculating the estimated glomerular fltration rate (eGFR) using the serum creatinine; and kidney biopsy and CT scan to evaluate for abnormal anatomy. Dialysis and kidney transplantation are used to treat kidney failure; one (or both sequentially) of these are almost always used when renal function drops below 15%. Nephrectomy is frequently used to cure renal cell carcinoma.

Ureters

In human anatomy, the ureters are tubes made of smooth muscle fbers that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually 25–30 cm (10–12 in) long and around 3–4 mm (0.12–0.16 in) in diameter. Histologically, the ureter is lined by the urothelium, a type of transitional epithelium, and has an additional smooth muscle layer in the more distal one-third to assist with peristalsis.

Bladder

Te urinary bladder is a hollow muscular organ in people and animals that collects and stores urine from the kidneys before disposal by urination. In the human the bladder is a hollow muscular, and distensible (or elastic) organ, that sits on the pelvic foor. Urine enters the bladder via the ureters and exits via the urethra. Te typical human bladder will hold between 300 and 500 mL (10.14 and 16.91 f oz) before the urge to empty occurs, but can hold considerably more.

Urethra

In anatomy, the urethra (from Greek οὐρήθρα – ourḗthrā) is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body. In males, the urethra travels through the penis and also carries semen. In human females (and in other primates), the urethra connects to the urinary meatus above the vagina, whereas in non- primates, the female's urethra empties into the urogenital sinus.[citation needed]

Females use their urethra only for urinating, but males use their urethra for both urination and ejaculation. Te external urethral sphincter is a striated muscle that allows voluntary control over urination. Only in the male is there an additional internal urethral sphincter muscle.

Reproductive organs

A sex organ (also called a reproductive organ, primary sex organ or primary sexual characteristic) is any anatomical part of the body in a complex organism that is involved in sexual reproduction and together constitute the reproductive system. Te external and visible organs, in males and females, are the primary sex organs known as the genitals or genitalia. Te internal organs are known as the secondary sex organs[not in citation given and are sometimes referred to as the internal genitalia. Te characteristics that begin to appear during puberty, such as, in humans, pubic hair on both sexes and facial hair on the male, are known as secondary sex characteristics.

Mosses, ferns, and some similar plants have gametangia for reproductive organs, which are part of the gametophyte. Te fowers of fowering plants produce pollen and egg cells, but the sex organs themselves are inside the gametophytes within the pollen and the ovule. Coniferous plants likewise produce their sexually reproductive structures within the gametophytes contained within the cones and pollen. Te cones and pollen are not themselves sexual organs.

Female reproductive system

Te female reproductive system (or female genital system) is made up of the internal and external sex organs that function in human reproduction. Te female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a fetus to full term. Te internal sex organs are the uterus and Fallopian tubes, and the ovaries. Te uterus or womb accommodates the embryo which develops into the fetus. Te uterus also produces vaginal and uterine secretions which help the transit of sperm to the Fallopian tubes. Te ovaries produce the ova (egg cells). Te external sex organs are also known as the genitals and these are the organs of the vulva including the labia, clitoris and vaginal opening. Te vagina is connected to the uterus at the cervix.

108 At certain intervals, the ovaries release an ovum, which passes through the Fallopian tube into the uterus. If, in this transit, it meets with sperm, a single sperm can enter and merge with the egg, fertilizing it. Te corresponding equivalent among males is the male reproductive system.

Fertilization usually occurs in the Fallopian tubes and marks the beginning of embryogenesis. Te zygote will then divide over enough generations of cells to form a blastocyst, which implants itself in the wall of the uterus. Tis begins the period of gestation and the embryo will continue to develop until full-term. When the fetus has developed enough to survive outside the uterus, the cervix dilates and contractions of the uterus propel the newborn through the birth canal (the vagina).

Ovaries

Te ovary is an organ found in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilised by a sperm. Tere is an ovary (from Latin ovarium, meaning egg' or 'nut) found on the left and the right side of the body. Te ovaries also secrete hormones that play a role in the menstrual cycle and fertility. Te ovary progresses through many stages beginning in the prenatal period through menopause. It is also an endocrine gland because of the various hormones that it secretes.

Fallopian tubes

Te Fallopian tubes, also known as uterine tubes or salpinges (singular salpinx), are two very fne tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the uterotubal junction. Tey enable the passage of egg cells from the ovaries to the uterus. In non-mammalian vertebrates, the equivalent structures are called oviducts.

Uterus

Te uterus (from Latin "uterus", plural uteri) or womb is a major female hormone-responsive reproductive sex organ of humans and most other mammals. In the human, the lower end of the uterus, the cervix, opens into the vagina, while the other end, the fundus, is connected to the fallopian tubes. It is within the uterus that the fetus develops during gestation. In the embryo, the uterus develops from the paramesonephric ducts which fuse into the single organ known as a simplex uterus. Te uterus has diﬀerent forms in many other animals and in some it exists as two separate uteri known as a duplex uterus.

In English, the term uterus is used consistently within the medical and related professions, while the Germanic-derived term womb is also commonly used in everyday contexts.

Vagina

In mammals, the vagina is the fbromuscular, tubular part of the female genital tract extending, in humans, from the vulva to the cervix. Te outer vaginal opening is normally partly covered by a membrane called the hymen. At the deep end, the cervix (neck of the uterus) bulges into the vagina. Te vagina allows for sexual intercourse and childbirth, and channels menstrual fow (menses), which occurs as part of the monthly menstrual cycle.

Te vagina's location and structure varies among species, and can vary in size. Female mammals usually have two external openings in the vulva, the urethral opening for the urinary tract and the vaginal opening for the genital tract. Tis is diﬀerent from male mammals, who usually have a single urethral opening for both urination and reproduction. Te vaginal opening is much larger than the nearby urethral opening, and both are protected by the labia in humans. In amphibians, birds, reptiles and monotremes, the cloaca is the single external opening for the gastrointestinal tract, the urinary, and reproductive tracts.

To accommodate smoother penetration of the vagina during sexual intercourse or other sexual activity, vaginal moisture increases during sexual arousal in human females and also in other female mammals. Tis increase in moisture provides vaginal lubrication, which reduces friction. Te texture of the vaginal walls creates friction for the penis during sexual intercourse and stimulates it toward ejaculation, enabling fertilization. Along with pleasure and bonding, women's sexual behavior with others (which can include heterosexual or lesbian sexual activity) can result in sexually transmitted infections (STIs), the risk of which can be reduced by recommended safe sex practices. Other disorders may also aﬀect the human vagina.

Te vagina and vulva have evoked strong reactions in societies throughout history, including negative perceptions and language, cultural taboos, and their use as symbols for female sexuality, spirituality, or regeneration of life. In common speech, the word vagina is often used to refer to the vulva or to the female genitals in general. By its dictionary and

109 anatomical defnitions, however, vagina refers exclusively to the specifc internal structure, and understanding the distinction can improve knowledge of the female genitalia and aid in health care communication.

Vulva

Te vulva (Latin: wrapper, covering, plural vulvae or vulvas) consists of the external female sex organs. Te vulva includes the mons pubis, labia majora, labia minora, clitoris, bulb of vestibule, vulval vestibule, urinary meatus, greater and lesser vestibular glands, and the vaginal opening. Te urinary meatus is also included as it opens into the vulval vestibule. Other features of the vulva include: the pudendal cleft, sebaceous glands, the urogenital triangle (anterior part of the perineum), and pubic hair.

Te vulva includes the entrance to the vagina, which leads to the uterus, and provides a double layer of protection for this by the folds of the outer and inner labia. Te vulva can be aﬀected by many disorders which can often result in irritation. Vulvovaginal health measures can prevent many of these.

Clitoris

Te clitoris (/ˈklɪtərɪs/ (About this sound listen) or /klɪˈtɔːrɪs/ (About this sound listen)) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible button-like portion is near the front junction of the labia minora (inner lips), above the opening of the urethra. Unlike the penis, the male homologue (equivalent) to the clitoris, it usually does not contain the distal portion (or opening) of the urethra and is therefore not used for urination. While few animals urinate through the clitoris, the spotted hyena, which has an especially well-developed clitoris, urinates, mates and gives birth via the organ. Some other mammals, such as lemurs and spider monkeys, also have a well-developed clitoris.

Te clitoris is the human female's most sensitive erogenous zone and generally the primary anatomical source of human female sexual pleasure. In humans and other mammals, it develops from an outgrowth in the embryo called the genital tubercle. Initially undiﬀerentiated, the tubercle develops into either a penis or a clitoris, depending on the presence or absence of the protein tdf, which is codifed by a single gene on the Y chromosome. Te clitoris is a complex structure, and its size and sensitivity can vary. Te glans (head) of the human clitoris is roughly the size and shape of a pea, and is estimated to have more than 8,000 sensory nerve endings.

Extensive sociological, sexological and medical debate have focused on the clitoris, primarily concerning anatomical accuracy, orgasmic factors and their physiological explanation for the G-spot, and whether the clitoris is vestigial, an adaptation, or serves a reproductive function. Social perceptions of the clitoris range from the signifcance of its role in female sexual pleasure, assumptions about its true size and depth, and varying beliefs regarding genital modifcation such as clitoris enlargement, clitoris piercing and clitoridectomy. Genital modifcation may be for aesthetic, medical or cultural reasons.

Knowledge of the clitoris is signifcantly impacted by cultural perceptions of the organ. Studies suggest that knowledge of its existence and anatomy is scant in comparison with that of other sexual organs, and that more education about it could help alleviate social stigmas associated with the female body and female sexual pleasure; for example, that the clitoris and vulva in general are visually unappealing, that female masturbation is taboo, or that men should be expected to master and control women's orgasms.

Placenta

Te placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, thermo-regulation, waste elimination, and gas exchange via the mother's blood supply; to fght against internal infection; and to produce hormones which support pregnancy. Te placenta provides oxygen and nutrients to growing fetuses and removes waste products from the fetus's blood. Te placenta attaches to the wall of the uterus, and the fetus's umbilical cord develops from the placenta. Tese organs connect the mother and the fetus. Placentas are a defning characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development. Te homology of such structures in various viviparous organisms is debatable, and in invertebrates such as Arthropoda, is analogous at best.

Te word placenta comes from the Latin word for cake, from Greek πλακόεντα/πλακοῦντα plakóenta/plakoúnta, accusative of πλακόεις/ πλακούς plakóeis/plakoús, "fat, slab-like", in reference to its round, fat appearance in humans. Te classical plural is placentae, but the form placentas is common in modern English and probably has the wider currency at present.

110 Te placenta functions as a fetomaternal organ with two components: the fetal placenta (Chorion frondosum), which develops from the same blastocyst that forms the fetus, and the maternal placenta (Decidua basalis), which develops from the maternal uterine tissue. It metabolises a number of substances and can release metabolic products into maternal or fetal circulation

Testes

Te testicle or testis is the male reproductive gland in all animals, including humans. It is homologous to the female ovary. Te functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone; whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone.

Epididymis

Te epididymis (/ɛpɪˈdɪdɪmɪs/; plural: epididymides /ɛpɪdɪˈdɪmədiːz/ or /ɛpɪˈdɪdəmɪdiːz/) is a tube that connects a testicle to a vas deferens in the male reproductive system. It is present in all male reptiles, birds, and mammals. It is a single, narrow, tightly-coiled tube (in adult humans, six to seven meters in length) connecting the eﬀerent ducts from the rear of each testicle to its vas deferens.

Vas deferens

Te vas deferens (Latin: "carrying-away vessel"; plural: vasa deferentia), also called ductus deferens (Latin: "carrying-away duct"; plural: ductus deferentes), is part of the male reproductive system of many vertebrates; these vasa transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. It is a partially coiled tube which exits the abdominal cavity through the inguinal canal.

Seminal vesicles

Te seminal vesicles (Latin: glandulae vesiculosae), vesicular glands, or seminal glands, are a pair of simple tubular glands posteroinferior to the urinary bladder of some male mammals. Seminal vesicles are located within the pelvis. Tey secrete fuid that partly composes the semen.

Prostate

Te prostate (from Ancient Greek προστάτης, prostates, literally "one who stands before", "protector", "guardian") is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals. It diﬀers considerably among species anatomically, chemically, and physiologically.

Te function of the prostate is to secrete a slightly alkaline fuid, milky or white in appearance, that in humans usually constitutes roughly 30% of the volume of the semen along with spermatozoa and seminal vesicle fuid. Semen is made alkaline overall with the secretions from the other contributing glands, including, at least, the seminal vesicle fuid. Te alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. Te prostatic fuid is expelled in the frst ejaculate fractions, together with most of the spermatozoa. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fuid, those expelled in prostatic fuid have better motility, longer survival and better protection of the genetic material.

Te prostate also contains some smooth muscles that help expel semen during ejaculation. Bulbourethral glands

A bulbourethral gland, also called a Cowper's gland for English anatomist William Cowper, is one of two small exocrine glands in the reproductive system of many male mammals (of all domesticated animals, they are only absent in the dog). Tey are homologous to Bartholin's glands in females.

External reproductive organs Penis

A penis (plural penises or penes /-niːz/) is the primary sexual organ that male animals use to inseminate sexually receptive mates (usually females and hermaphrodites respectively) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penes in the various species are not necessarily homologous. For example, the penis of a mammal is at most analogous to the penis of a male insect or barnacle.

111 Te term penis applies to many intromittent organs, but not to all; for example the intromittent organ of most cephalopoda is the hectocotylus, a specialised arm, and male spiders use their pedipalps. Even within the Vertebrata there are morphological variants with specifc terminology, such as hemipenes.

In most species of animals in which there is an organ that might reasonably be described as a penis, it has no major function other than intromission, or at least conveying the sperm to the female, but in the placental mammals the penis bears the distal part of the urethra, which discharges both urine during urination and semen during copulation.

Scrotum

Te scrotum is an anatomical male reproductive structure that consists of a suspended dual-chambered sack of skin and smooth muscle that is present in most terrestrial male mammals and located under the penis. One testis is typically lower than the other to avoid compression in the event of impact. Te perineal raphe is a small, vertical, slightly raised ridge of scrotal skin under which is found the scrotal septum. It appears as a thin longitudinal line that runs front to back over the entire scrotum. Te scrotum contains the external spermatic fascia, testes, epididymis and ductus deferens. It is a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery, testicular vein and pampiniform plexus. In humans and some other mammals, the scrotum becomes covered with pubic hair at puberty. Te scrotum will usually tighten during penile erection and when exposed to cold temperature.

Te scrotum is biologically homologous to the labia majora in females. Although present in most mammals, the external scrotum is absent in streamlined marine mammals, such as whales and seals, as well as in some lineages of land mammals, such as the afrotherians, xenarthrans, and numerous families of bats, rodents, and insectivores.

Endocrine system

Te endocrine system is a chemical messenger system consisting of hormones, the group of glands of an organism that secrete those hormones directly into the circulatory system to regulate the function of distant target organs, and the feedback loops which modulate hormone release so that homeostasis is maintained. In humans, the major endocrine glands are the thyroid gland and the adrenal glands. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. Te feld of study dealing with the endocrine system and its disorders is endocrinology, a branch of internal medicine.

Special features of endocrine glands are, in general, their ductless nature, their vascularity, and commonly the presence of intracellular vacuoles or granules that store their hormones. In contrast, exocrine glands, such as salivary glands, sweat glands, and glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen. A number of glands that signal each other in sequence are usually referred to as an axis, for example, the hypothalamic- pituitary-adrenal axis.

In addition to the specialized endocrine organs mentioned above, many other organs that are part of other body systems, such as bone, kidney, liver, heart and gonads, have secondary endocrine functions. For example, the kidney secretes endocrine hormones such as erythropoietin and renin. Hormones can consist of either amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins.

Te endocrine system is in contrast to the exocrine system, which secretes its hormones to the outside of the body using ducts. As opposed to endocrine factors that travel considerably longer distances via the circulatory system, other signaling molecules, such as paracrine factors involved in paracrine signalling diﬀuse over a relatively short distance.

Te word endocrine derives via New Latin from the Greek words ἔνδον, endon, "inside, within," and "exocrine" from the κρίνω, krīnō, "to separate, distinguish”.

Pituitary gland

In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 grams (0.018 oz) in humans. It is a protrusion oﬀ the bottom of the hypothalamus at the base of the brain. Te hypophysis rests upon the hypophysial fossa of the sphenoid bone in the center of the middle cranial fossa and is surrounded by a small bony cavity (sella turcica) covered by a dural fold (diaphragma sellae). Te anterior pituitary (or adenohypophysis) is a lobe of the gland that regulates several physiological processes (including stress, growth, reproduction, and lactation). Te intermediate lobe synthesizes and secretes melanocyte-stimulating hormone. Te posterior pituitary (or neurohypophysis) is a lobe of the gland that is functionally connected to the hypothalamus by the median eminence via a small tube called the pituitary stalk (also called the infundibular stalk or the infundibulum).

112 Hormones secreted from the pituitary gland help control: growth, blood pressure, management of energy, all functions of the sex organs, thyroid glands and metabolism as well as some aspects of pregnancy, childbirth, nursing, water/salt concentration at the kidneys, temperature regulation and pain relief.

Pineal gland

Te pineal gland, also known as the conarium or epiphysis cerebri, is a small endocrine gland in the vertebrate brain. Te pineal gland produces melatonin, a serotonin derived hormone which modulates sleep patterns in both circadian and seasonal cycles. Te shape of the gland resembles a pine cone, hence its name. Te pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join.

Nearly all vertebrate species possess a pineal gland. Te most important exception is the hagfsh, which is often thought of as the most primitive extant vertebrate. Even in the hagfsh, however, there may be a "pineal equivalent" structure in the dorsal diencephalon. Te lancelet Branchiostoma lanceolatum, the nearest existing relative to vertebrates, also lacks a recognizable pineal gland. Te lamprey (considered almost as primitive as the hagfsh), however, does possess one. A few more developed vertebrates lost pineal glands over the course of their evolution.

Te results of various scientifc research in evolutionary biology, comparative neuroanatomy and neurophysiology, have explained the phylogeny of the pineal gland in diﬀerent vertebrate species. From the point of view of biological evolution, the pineal gland represents a kind of atrophied photoreceptor. In the epithalamus of some species of amphibians and reptiles, it is linked to a light-sensing organ, known as the parietal eye, which is also called the pineal eye or third eye.

René Descartes believed the pineal gland to be the "principal seat of the soul". Academic philosophy among his contemporaries considered the pineal gland as a neuroanatomical structure without special metaphysical qualities; science studied it as one endocrine gland among many. However, the pineal gland continues to have an exalted status in the realm of pseudoscience.

Tyroid gland

Te thyroid gland, or simply the thyroid, is an endocrine gland in the neck, consisting of two lobes connected by an isthmus. It is found at the front of the neck, below the Adam's apple. Te thyroid gland secretes thyroid hormones, which primarily infuence the metabolic rate and protein synthesis. Te hormones also have many other eﬀects including those on development. Te thyroid hormones triiodothyronine (T3) and thyroxine (T4) are created from iodine and tyrosine. Te thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis.

Hormonal output from the thyroid is regulated by thyroid-stimulating hormone (TSH) secreted from the anterior pituitary gland, which itself is regulated by thyrotropin-releasing hormone (TRH) produced by the hypothalamus.

Te thyroid may be affected by several diseases. Hyperthyroidism occurs when the gland produces excessive amounts of thyroid hormones, the most common cause being Graves' disease — an autoimmune disorder. In contrast, hypothyroidism is a state of insufficient thyroid hormone production. Worldwide, the most common cause is iodine defciency. Tyroid hormones are important for development, and hypothyroidism secondary to iodine defciency remains the leading cause of preventable intellectual disability. In iodine-sufficient regions, the most common cause of hypothyroidism is Hashimoto's thyroiditis—also an autoimmune disease. In addition, the thyroid gland may also develop several types of nodules and cancer.

Parathyroid glands

Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods that produce parathyroid hormone. Humans usually have four parathyroid glands, variably located on the back of the thyroid gland. Parathyroid hormone and calcitonin (one of the hormones made by the thyroid gland) have key roles in regulating the amount of calcium in the blood and within the bones.

Parathyroid glands share a similar blood supply, venous drainage, and lymphatic drainage to the thyroid glands. Parathyroid glands are derived from the epithelial lining of the third and fourth pharyngeal pouches, with the superior glands arising from the fourth pouch, and the inferior glands arising from the higher third pouch. Te relative position of the inferior and superior glands, which are named according to their fnal location, changes because of the migration of embryological tissues.

113 Hyperparathyroidism and hypoparathyroidism, characterized by alterations in the blood calcium levels and bone metabolism, are states of either surplus or defcient parathyroid function,.

Adrenal glands

Te adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. Tey are found above the kidneys. Each gland has an outer cortex which produces steroid hormones and an inner medulla. Te adrenal cortex itself is divided into three zones: zona glomerulosa, the zona fasciculata and the zona reticularis.

Te adrenal cortex produces three main types of steroid hormones: mineralocorticoids, glucocorticoids, and androgens. Mineralocorticoids (such as aldosterone) produced in the zona glomerulosa help in the regulation of blood pressure and electrolyte balance. Te glucocorticoids cortisol and corticosterone are synthesized in the zona fasciculata; their functions include the regulation of metabolism and immune system suppression. Te innermost layer of the cortex, the zona reticularis, produces androgens that are converted to fully functional sex hormones in the gonads and other target organs. Te production of steroid hormones is called steroidogenesis, and involves a number of reactions and processes that take place in cortical cells. Te medulla produces the catecholamines adrenaline and noradrenaline, which function to produce a rapid response throughout the body in stress situations.

A number of endocrine diseases involve disfunctions of the adrenal gland. Overproduction of cortisol leads to Cushing's syndrome, whereas insuﬃcient production is associated with Addison's disease. Congenital adrenal hyperplasia is a genetic disease produced by dysregulation of endocrine control mechanisms. A variety of tumors can arise from adrenal tissue and are commonly found in medical imaging when searching for other diseases.

Pancreas

Circulatory system

Te circulatory system, also called the cardiovascular system or the vascular system, is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fghting diseases, stabilize temperature and pH, and maintain homeostasis.

Te circulatory system includes the lymphatic system, which circulates lymph.Te passage of lymph for example takes much longer than that of blood. Blood is a fuid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. Lymph is essentially recycled excess blood plasma after it has been fltered from the interstitial fuid (between cells) and returned to the lymphatic system. Te cardiovascular (from Latin words meaning "heart" and "vessel") system comprises the blood, heart, and blood vessels. Te lymph, lymph nodes, and lymph vessels form the lymphatic system, which returns fltered blood plasma from the interstitial fuid (between cells) as lymph.

Te circulatory system of the blood is seen as having two components, a systemic circulation and a pulmonary circulation.

While humans, as well as other vertebrates, have a closed cardiovascular system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open cardiovascular system. Te lymphatic system, on the other hand, is an open system providing an accessory route for excess interstitial fuid to be returned to the blood.Te more primitive, diploblastic animal phyla lack circulatory systems.

Heart

Te heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen and nutrients, as well as assists in the removal of metabolic wastes. In humans, the heart is located between the lungs, in the middle compartment of the chest. 114 In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria; and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. Fish, in contrast, have two chambers, an atrium and a ventricle, while reptiles have three chambers. In a healthy heart blood fows one way through the heart due to heart valves, which prevent backfow. Te heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fuid. Te wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.

Te heart pumps blood with a rhythm determined by a group of pacemaking cells in the sinoatrial node. Tese generate a current that causes contraction of the heart, traveling through the atrioventricular node and along the conduction system of the heart. Te heart receives blood low in oxygen from the systemic circulation, which enters the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here it is pumped into the pulmonary circulation, through the lungs where it receives oxygen and gives oﬀ carbon dioxide. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta to the systemic circulation−where the oxygen is used and metabolized to carbon dioxide. Te heart beats at a resting rate close to 72 beats per minute. Exercise temporarily increases the rate, but lowers resting heart rate in the long term, and is good for heart health.

Cardiovascular diseases (CVD) are the most common cause of death globally as of 2008, accounting for 30% of deaths. Of these more than three quarters are a result of coronary artery disease and stroke. Risk factors include: smoking, being overweight, little exercise, high cholesterol, high blood pressure, and poorly controlled diabetes, among others. Cardiovascular diseases frequently do not have symptoms or may cause chest pain or shortness of breath. Diagnosis of heart disease is often done by the taking of a medical history, listening to the heart-sounds with a stethoscope, ECG, and ultrasound. Specialists who focus on diseases of the heart are called cardiologists, although many specialties of medicine may be involved in treatment.

Arteries

An artery (plural arteries) (from Greek ἀρτηρία (artēria), meaning 'windpipe, artery') is a blood vessel that takes blood from the heart to all parts of the body. Most arteries carry oxygenated blood; the two exceptions are the pulmonary and the umbilical arteries, which carry deoxygenated blood to the organs that oxygenate it. Te eﬀective arterial blood volume is that extracellular fuid which flls the arterial system.

Te arteries are part of the circulatory system, which is responsible for the delivery of oxygen and nutrients to all cells, as well as the removal of carbon dioxide and waste products, the maintenance of optimum blood pH, and the circulation of proteins and cells of the immune system. In developed countries, the two leading causes of death, myocardial infarction (heart attack), and stroke, may each directly result from an arterial system that has been slowly and progressively compromised by years of deterioration.

Veins

Veins are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart.

Capillaries

A capillary (/ˈkæpɪlɛri/ in US; /kəˈpɪləri/ in UK) is a small blood vessel from 5 to 10 micrometres (μm) in diameter, and having a wall one endothelial cell thick. Tey are the smallest blood vessels in the body: they convey blood between the arterioles and venules. Tese microvessels are the site of exchange of many substances with the interstitial fuid surrounding them. Substances which exit include water (proximal portion), oxygen, and glucose; substances which enter include water (distal portion), carbon dioxide, uric acid, lactic acid, urea and creatinine. Lymph capillaries connect with larger lymph vessels to drain lymphatic fuid collected in the microcirculation.

During early embryonic development new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a de novo production of endothelial cells which then form vascular tubes. Te term angiogenesis denotes the formation of new capillaries from pre-existing blood vessels and already present endothelium which divides.

Lymphatic system

115 Te lymphatic system is part of the circulatory system and an important part of the immune system, comprising a network of lymphatic vessels that carry a clear fuid called lymph (from Latin, lympha meaning "water") directionally towards the heart. Te lymphatic system was frst described in the seventeenth century independently by Olaus Rudbeck and Tomas Bartholin. Unlike the circulatory system, the lymphatic system is not a closed system. Te human circulatory system processes an average of 20 liters of blood per day through capillary fltration, which removes plasma while leaving the blood cells. Roughly 17 litres of the fltered plasma are reabsorbed directly into the blood vessels, while the remaining three litres remain in the interstitial fuid. One of the main functions of the lymph system is to provide an accessory return route to the blood for the surplus three litres.

Te other main function is that of defense in the immune system. Lymph is very similar to blood plasma: it contains lymphocytes. It also contains waste products and cellular debris together with bacteria and proteins. Associated organs composed of lymphoid tissue are the sites of lymphocyte production. Lymphocytes are concentrated in the lymph nodes. Te spleen and the thymus are also lymphoid organs of the immune system. Te tonsils are lymphoid organs that are also associated with the digestive system. Lymphoid tissues contain lymphocytes, and also contain other types of cells for support.Te system also includes all the structures dedicated to the circulation and production of lymphocytes (the primary cellular component of lymph), which also includes the bone marrow, and the lymphoid tissue associated with the digestive system.

Te blood does not come into direct contact with the parenchymal cells and tissues in the body (except in case of an injury causing rupture of one or more blood vessels), but constituents of the blood frst exit the microvascular exchange blood vessels to become interstitial fuid, which comes into contact with the parenchymal cells of the body. Lymph is the fuid that is formed when interstitial fuid enters the initial lymphatic vessels of the lymphatic system. Te lymph is then moved along the lymphatic vessel network by either intrinsic contractions of the lymphatic passages or by extrinsic compression of the lymphatic vessels via external tissue forces (e.g., the contractions of skeletal muscles), or by lymph hearts in some animals. Te organization of lymph nodes and drainage follows the organization of the body into external and internal regions; therefore, the lymphatic drainage of the head, limbs, and body cavity walls follows an external route, and the lymphatic drainage of the thorax, abdomen, and pelvic cavities follows an internal route.[5] Eventually, the lymph vessels empty into the lymphatic ducts, which drain into one of the two subclavian veins, near their junction with the internal jugular veins.

Lymphatic system Lymphatic vessel

In anatomy, lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessels are lined by endothelial cells, and have a thin layer of smooth muscle, and adventitia that bind the lymph vessels to the surrounding tissue. Lymph vessels are devoted to the propulsion of the lymph from the lymph capillaries, which are mainly concerned with absorption of interstitial fuid from the tissues. Lymph capillaries are slightly larger than their counterpart capillaries of the vascular system. Lymph vessels that carry lymph to a lymph node are called aﬀerent lymph vessels, and those that carry it from a lymph node are called eﬀerent lymph vessels, from where the lymph may travel to another lymph node, may be returned to a vein, or may travel to a larger lymph duct. Lymph ducts drain the lymph into one of the subclavian veins and thus return it to general circulation.

Generally, lymph fows away from the tissues to lymph nodes and eventually to either the right lymphatic duct or the largest lymph vessel in the body, the thoracic duct. Tese vessels drain into the right and left subclavian veins respectively.

Lymph node

A lymph node or lymph gland is an ovoid or kidney-shaped organ of the lymphatic system, and of the adaptive immune system, that is widely present throughout the body. Tey are linked by the lymphatic vessels as a part of the circulatory system. Lymph nodes are major sites of B and T lymphocytes, and other white blood cells. Lymph nodes are important for the proper functioning of the immune system, acting as flters for foreign particles and cancer cells. Lymph nodes do not have a detoxifcation function, which is primarily dealt with by the liver and kidneys.

In the lymphatic system the lymph node is a secondary lymphoid organ. A lymph node is enclosed in a fbrous capsule and is made up of an outer cortex and an inner medulla.

Lymph nodes also have clinical signifcance. Tey become infamed or enlarged in various diseases which may range from trivial throat infections, to life- threatening cancers. Te condition of the lymph nodes is very important in cancer staging, which decides the treatment to be used, and determines the prognosis. When swollen, infamed or enlarged, lymph nodes can be hard, frm or tender.

116 Bone marrow

Bone marrow is a semi-solid tissue which may be found within the spongy or cancellous portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production or hematopoiesis. It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately 2.6 kilograms (5.7 lb).[4] Human marrow produces approximately 500 billion blood cells per day, which join the systemic circulation via permeable vasculature sinusoids within the medullary cavity.[5] All types of hematopoietic cells, including both myeloid and lymphoid lineages, are created in bone marrow; however, lymphoid cells must migrate to other lymphoid organs (e.g. thymus) in order to complete maturation.

Bone marrow transplants can be conducted to treat severe diseases of the bone marrow, including certain forms of cancer such as leukemia. Additionally, bone marrow stem cells have been successfully transformed into functional neural cells, and can also potentially be used to treat illnesses such as infammatory bowel disease.

Tymus Te thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts specifcally to foreign invaders. Te thymus is composed of two identical lobes and is located anatomically in the anterior superior mediastinum, in front of the heart and behind the sternum. Histologically, each lobe of the thymus can be divided into a central medulla and a peripheral cortex which is surrounded by an outer capsule. Te cortex and medulla play diﬀerent roles in the development of T cells. Cells in the thymus can be divided into thymic stromal cells and cells of hematopoietic origin (derived from bone marrow resident hematopoietic stem cells). Developing T cells are referred to as thymocytes and are of hematopoietic origin. Stromal cells include epithelial cells of the thymic cortex and medulla, and dendritic cells.

Te thymus provides an inductive environment for development of T cells from hematopoietic progenitor cells. In addition, thymic stromal cells allow for the selection of a functional and self-tolerant T cell repertoire. Terefore, one of the most important roles of the thymus is the induction of central tolerance.

Te thymus is largest and most active during the neonatal and pre-adolescent periods. By the early teens, the thymus begins to atrophy and thymic stroma is mostly replaced by adipose (fat) tissue. Nevertheless, residual T lymphopoiesis continues throughout adult life.

Spleen

Te spleen (from Greek σπλήν—splḗn[1]) is an organ found in virtually all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood flter.

Te spleen plays important roles in regard to red blood cells (also referred to as erythrocytes) and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron. As a part of the mononuclear phagocyte system, it metabolizes hemoglobin removed from senescent red blood cells (erythrocytes). Te globin portion of hemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin, which is removed in the liver.

Te spleen synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation. A study published in 2009 using mice found that the red pulp of the spleen forms a reservoir that contains over half of the body's monocytes. Tese monocytes, upon moving to injured tissue (such as the heart after myocardial infarction), turn into dendritic cells and macrophages while promoting tissue healing. Te spleen is a center of activity of the mononuclear phagocyte system and can be considered analogous to a large lymph node, as its absence causes a predisposition to certain infections.

In humans the spleen is brownish in color and is located in the left upper quadrant of the abdomen. Gut-associated lymphoid tissue

Gut-associated lymphoid tissue (GALT)[1] is a component of the mucosa-associated lymphoid tissue (MALT) which works in the immune system to protect the body from invasion in the gut.

Owing to its physiological function in food absorption, the mucosal surface is thin and acts as a permeable barrier to the interior of the body. Equally, its fragility and permeability creates vulnerability to infection and, in fact, the vast majority of the infectious agents invading the human body use this route. Te functional importance of GALT in body's defense relies 117 on its large population of plasma cells, which are antibody producers, whose number exceeds the number of plasma cells in spleen, lymph nodes and bone marrow combined.

Tonsils

Tonsils are collections of lymphoid tissue facing into the aerodigestive tract. Te set of lymphatic tissue known as Waldeyer's tonsillar ring includes the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsil.

When used unqualifed, the term most commonly refers specifcally to the palatine tonsils, which are masses of lymphatic material situated at either side of the back of the human throat. Te palatine tonsils and the nasopharyngeal tonsil are lymphoepithelial tissues located near the oropharynx and nasopharynx (parts of the throat).

Nervous system

Te nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. Te nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events[1]. Nervous tissue frst arose in wormlike organisms about 550 to 600 million years ago. In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). Te CNS consists of the brain and spinal cord. Te PNS consists mainly of nerves, which are enclosed bundles of the long fbers or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called motor or efferent nerves, while those nerves that transmit information from the body to the CNS are called sensory or afferent. Spinal nerves serve both functions and are called mixed nerves. Te PNS is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems. Somatic nerves mediate voluntary movement. Te autonomic nervous system is further subdivided into the sympathetic and the parasympathetic nervous systems. Te sympathetic nervous system is activated in cases of emergencies to mobilize energy, while the parasympathetic nervous system is activated when organisms are in a relaxed state. Te enteric nervous system functions to control the gastrointestinal system. Both autonomic and enteric nervous systems function involuntarily. Nerves that exit from the cranium are called cranial nerves while those exiting from the spinal cord are called spinal nerves.

At the cellular level, the nervous system is defned by the presence of a special type of cell, called the neuron, also known as a "nerve cell". Neurons have special structures that allow them to send signals rapidly and precisely to other cells. Tey send these signals in the form of electrochemical waves traveling along thin fbers called axons, which cause chemicals called neurotransmitters to be released at junctions called synapses. A cell that receives a synaptic signal from a neuron may be excited, inhibited, or otherwise modulated. Te connections between neurons can form neural circuits and also neural networks that generate an organism's perception of the world and determine its behavior. Along with neurons, the nervous system contains other specialized cells called glial cells (or simply glia), which provide structural and metabolic support.

Nervous systems are found in most multicellular animals, but vary greatly in complexity. Te only multicellular animals that have no nervous system at all are sponges, placozoans, and mesozoans, which have very simple body plans. Te nervous systems of the radially symmetric organisms ctenophores (comb jellies) and cnidarians (which include anemones, hydras, corals and jellyfsh) consist of a diﬀuse nerve net. All other animal species, with the exception of a few types of worm, have a nervous system containing a brain, a central cord (or two cords running in parallel), and nerves radiating from the brain and central cord. Te size of the nervous system ranges from a few hundred cells in the simplest worms, to around 300 billion cells in African elephants.

Te central nervous system functions to send signals from one cell to others, or from one part of the body to others and to receive feedback. Malfunction of the nervous system can occur as a result of genetic defects, physical damage due to trauma or toxicity, infection or simply of ageing. Te medical specialty of neurology studies disorders of the nervous system and looks for interventions that can prevent or treat them. In the peripheral nervous system, the most common problem is the failure of nerve conduction, which can be due to diﬀerent causes including diabetic neuropathy and demyelinating disorders such as multiple sclerosis and amyotrophic lateral sclerosis. Neuroscience is the feld of science that focuses on the study of the nervous system.

Brain

Purendulum lowest deepest part of the brain

118 Comendulum second deepest part of the brain Serangeranlum third deepest part of the brain Seaurengalum frst highest part of the brain Narengardalum second highest part of the brain Purenarnadalum frst high point in brain in neo cortex Corenanaderlum second high point in neo cortex Parenasiseraliumerium fourth highest part of neo cortex back Aumeraniosemileireolium fourth highest part of neo cortex front Auremilourenaliriumeriam frontal ffth part Auremiloremileriumeriulerium frontal seventh part Aurameriliumeriliumurelerium back seventh part Curelaneneragenalerangeraum top of brain

Te brain is an organ that serves as the centre of the nervous system in all vertebrate and most invertebrate animals. Te brain is located in the head, usually close to the sensory organs for senses such as vision. Te brain is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 49 billion neurons, each connected by synapses to several 10-11,000 other neurons. Tese neurons communicate with one another by means of long protoplasmic fbers called axons God calls these fbres Xenotineri, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specifc recipient cells.

Physiologically, the function of the brain is to exert centralized control over the other organs of the body. Te brain acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. Tis centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness such as refexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires the information integrating capabilities of a centralized brain.

Te operations of individual brain cells are now understood in considerable detail but the way they cooperate in ensembles of millions is yet to be solved. Recent models in modern neuroscience treat the brain as a biological computer, very diﬀerent in mechanism from an electronic computer, but similar in the sense that it acquires information from the surrounding world, stores it, and processes it in a variety of ways.

Tis article compares the properties of brains across the entire range of animal species, with the greatest attention to vertebrates. It deals with the human brain insofar as it shares the properties of other brains. Te ways in which the human brain diﬀers from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because much more can be said about them in a human context. Te most important is brain disease and the eﬀects of brain damage, that are covered in the human brain article.

Cerebrum - corenanaderlum

Te cerebrum is a large part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In the human brain, the cerebrum is the uppermost region of the central nervous system. Te prosencephalon is the embryonic structure from which the cerebrum develops prenatally. In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. Te cerebrum is also divided into approximately symmetric left and right cerebral hemispheres.

With the assistance of the cerebellum, the cerebrum controls all voluntary actions in the body. Cerebral hemispheres

Te vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fssure. Te brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter, the cerebral cortex, that is supported by an inner layer of white matter. In eutherian (placental) mammals, the hemispheres are linked by the corpus callosum, a very large bundle of nerve fbers. Smaller commissures, including the anterior commissure, the posterior commissure and the fornix, also join the hemispheres and these are also present in other vertebrates. Tese commissures transfer information between the two hemispheres to coordinate localized functions.

Tere are three known poles of the cerebral hemispheres named : the occipital pole, the frontal pole, and the temporal lobe.

Te central sulcus is a prominent fssure which separates the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex.

119 Macroscopically the hemispheres are roughly mirror images of each other, with only subtle differences, such as the Yakovlevian torque seen in the human brain, which is a slight warping of the right side, bringing it just forward of the left side. On a microscopic level, the cytoarchitecture of the cerebral cortex, shows the functions of cells, quantities of neurotransmitter levels and receptor subtypes to be markedly asymmetrical between the hemispheres. However, while some of these hemispheric distribution differences are consistent across human beings, or even across some species, many observable distribution differences vary from individual to individual within a given species.

Diencephalon part of the Auremilourenaliriumeriam.

Te diencephalon of the brain consists of structures that are lateral to the third ventricle, and includes the thalamus, the hypothalamus, the epithalamus and the subthalamus.

Te diencephalon is one of the main vesicles of the brain formed during embryogenesis. During the third week of development a neural tube is created from the ectoderm, one of the three primary germ layers. Te tube forms three main vesicles during the third week of development: the prosencephalon, the mesencephalon and the rhombencephalon. Te prosencephlon gradually divides into the telencephalon and the diencephalon.

Te brainstem - Narengardalum

Te brainstem (or brain stem) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. In the human brain the brainstem includes the midbrain, the pons, and the medulla oblongata. Sometimes the diencephalon, the caudal part of the forebrain, is included.

Te brainstem provides the main motor and sensory innervation to the face and neck via the cranial nerves. Of the twelve pairs of cranial nerves, ten pairs come from the brainstem. Tough small, this is an extremely important part of the brain as the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body pass through the brainstem. Tis includes the corticospinal tract (motor), the posterior column-medial lemniscus pathway (fne touch, vibration sensation, and proprioception), and the spinothalamic tract (pain, temperature, itch, and crude touch).

Te brainstem also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system, and is pivotal in maintaining consciousness and regulating the sleep cycle. Te brainstem has many basic functions including heart rate, breathing, sleeping, and eating.

Midbrain Purenarnadalum to the Aumeraniosemileireolium

Te midbrain or mesencephalon (UK: /ˌmɛsɛnˈsɛfəlɒn/ or /-kɛfəlɒn/, US: /ˌmɛzənˈsɛfələn/;[1] from Greek mesos 'middle', and enkephalos 'brain') is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.

Pons - Comendulum Te pons is part of the brainstem, and in humans and other bipeds lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum.

Te pons is also called the pons Varolii ("bridge of Varolius"), after the Italian anatomist and surgeon Costanzo Varolio (1543–75).[1] Tis region of the brainstem includes neural pathways or tracts that conduct signals from the brain down to the cerebellum and medulla, and tracts that carry the sensory signals up into the thalamus.

Te pons in humans measures about 2.5 centimetres (0.98 in) in length. Most of it appears as a broad anterior bulge rostral to the medulla. Posteriorly, it consists mainly of two pairs of thick stalks called cerebellar peduncles. Tey connect the cerebellum to the pons and midbrain.

Te pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.

Within the pons is the pneumotaxic center consisting of the subparabrachial and the medial parabrachial nuclei. Tis center regulates the change from inhalation to exhalation. Tese are part of what God describes as the Parenasiseraliumerium.

Te pons is implicated in sleep paralysis, and may also play a role in generating dreams.[citation needed] Medulla oblongata

120 Te medulla oblongata (or medulla) is located in the brainstem, anterior and partially inferior to the cerebellum. It is a cone- shaped neuronal mass responsible for autonomic (involuntary) functions ranging from vomiting to sneezing. Te medulla contains the cardiac, respiratory, vomiting and vasomotor centers and therefore deals with the autonomic functions of breathing, heart rate and blood pressure. Tis is part of the Auremilourenaliriumeriam.

Te bulb is an archaic term for the medulla oblongata and in modern clinical usage the word bulbar (as in bulbar palsy) is retained for terms that relate to the medulla oblongata, particularly in reference to medical conditions. Te word bulbar can refer to the nerves and tracts connected to the medulla, and also by association to those muscles innervated, such as those of the tongue, pharynx and larynx. Tis is part of the Aurameriliumeriliumurelerium.

Cerebellum - Comendulum

Te cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fshes it may be as large as or even larger. In humans, the cerebellum plays an important role in motor control, and it may also be involved in some cognitive functions such as attention and language as well as in regulating fear and pleasure responses, but its movement-related functions are the most solidly established. Te human cerebellum does not initiate movement, but contributes to coordination, precision, and accurate timing: it receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fne-tune motor activity. Cerebellar damage produces disorders in fne movement, equilibrium, posture, and motor learning in humans.

Anatomically, the human cerebellum has the appearance of a separate structure attached to the bottom of the brain, tucked underneath the cerebral hemispheres. Its cortical surface is covered with fnely spaced parallel grooves, in striking contrast to the broad irregular convolutions of the cerebral cortex. Tese parallel grooves conceal the fact that the cerebellar cortex is actually a continuous thin layer of tissue tightly folded in the style of an accordion. Within this thin layer are several types of neurons with a highly regular arrangement, the most important being Purkinje cells and granule cells. Tis complex neural organization gives rise to a massive signal-processing capability, but almost all of the output from the cerebellar cortex passes through a set of small deep nuclei lying in the white matter interior of the cerebellum.

In addition to its direct role in motor control, the cerebellum is necessary for several types of motor learning, most notably learning to adjust to changes in sensorimotor relationships. Several theoretical models have been developed to explain sensorimotor calibration in terms of synaptic plasticity within the cerebellum. Tese models derive from those formulated by David Marr and James Albus, based on the observation that each cerebellar Purkinje cell receives two dramatically diﬀerent types of input: one comprises thousands of weak inputs from the parallel fbers of the granule cells; the other is an extremely strong input from a single climbing fber. Te basic concept of the Marr–Albus theory is that the climbing fber serves as a "teaching signal", which induces a long-lasting change in the strength of parallel fber inputs. Observations of long-term depression in parallel fber inputs have provided support for theories of this type, but their validity remains controversial.

Te spinal cord

Te spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column. Te brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone where it passes through the foramen magnum, and meets and enters the spinal canal at the beginning of the cervical vertebrae. Te spinal cord extends down to between the frst and second lumbar vertebrae where it ends. Te enclosing bony vertebral column protects the relatively shorter spinal cord. It is around 45 cm (18 in) in men and around 43 cm (17 in) long in women. Also, the spinal cord has a varying width, ranging from 13 mm (1⁄2 in) thick in the cervical and lumbar regions to 6.4 mm (1⁄4 in) thick in the thoracic area.

Te spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, and from the aﬀerent fbers of the sensory neurons to the sensory cortex. It is also a center for coordinating many refexes and contains refex arcs that can independently control refexes and central pattern generators.

Te ventricular system

Te ventricular system is a set of four interconnected cavities (ventricles) in the brain, where the cerebrospinal fuid (CSF) is produced. Within each ventricle is a region of choroid plexus, a network of ependymal cells involved in the production of CSF. Te ventricular system is continuous with the central canal of the spinal cord (from the fourth ventricle) allowing for the fow of CSF to circulate. All of the ventricular system and the central canal of the spinal cord are lined with ependyma, a specialised form of epithelium.

121 Choroid plexus Te choroid plexus is a plexus of cells that produces the cerebrospinal fuid in the ventricles of the brain. Te choroid plexus consists of modifed ependymal cells.

Nerves

A nerve is an enclosed, cable-like bundle of axons (nerve fbers, the long and slender projections of neurons) in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons to peripheral organs.

In the central nervous system, the analogous structures are known as tracts. Neurons are sometimes called nerve cells, though this term is potentially misleading since many neurons do not form nerves, and nerves also include non-neuronal Schwann cells that coat the axons in myelin.

Each nerve is a cordlike structure containing bundles of axons. Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium. Te axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium. Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium.

Cranial nerves

Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves (which emerge from segments of the spinal cord). 10 of 12 of the cranial nerves originate in the brainstem. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck.

Spinal nerves emerge sequentially from the spinal cord with the spinal nerve closest to the head (C1) emerging in the space above the frst cervical vertebra. Te cranial nerves, however, emerge from the central nervous system above this level.[3] Each cranial nerve is paired and is present on both sides. Depending on defnition in humans there are twelve or thirteen cranial nerves pairs, which are assigned Roman numerals I–XII, sometimes also including cranial nerve zero. Te numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back (brainstem).

Te terminal nerves, olfactory nerves (I) and optic nerves (II) emerge from the cerebrum or forebrain, and the remaining ten pairs arise from the brainstem, which is the lower part of the brain.

Te cranial nerves are considered components of the peripheral nervous system (PNS), although on a structural level the olfactory, optic and terminal nerves are more accurately considered part of the central nervous system (CNS).

Spinal nerves

A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. Tese are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. Tere are eight pairs of cervical nerves, twelve pairs of thoracic nerves, fve pairs of lumbar nerves, fve pairs of sacral nerves, and one pair of coccygeal nerves. Te spinal nerves are part of the peripheral nervous system.

Ganglia

A ganglion is a nerve cell cluster or a group of nerve cell bodies located in the autonomic nervous system and sensory system. Ganglia house the cell bodies of aﬀerent nerves and eﬀerent nerves.

A pseudoganglion looks like a ganglion, but only has nerve fbers and has no nerve cell bodies. Enteric nervous system

Te enteric nervous system (ENS) or intrinsic nervous system is one of the main divisions of the autonomic nervous system and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independent of the sympathetic and parasympathetic nervous systems, although it may be infuenced by them. Te ENS is also called the second brain.

It is derived from neural crest cells. Sensory system

122 Te sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons (including the sensory receptor cells), neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, touch, taste, smell, and balance. In short, senses are transducers from the physical world to the realm of the mind where we interpret the information, creating our perception of the world around us.

Organisms need information to solve at least three kinds of problems: (a) to maintain an appropriate environment, i.e., homeostasis; (b) to time activities (e.g., seasonal changes in behavior) or synchronize activities with those of conspecifcs; and (c) to locate and respond to resources or threats (e.g., by moving towards resources or evading or attacking threats). Organisms also need to transmit information in order to infuence another's behavior: to identify themselves, warn conspecifcs of danger, coordinate activities, or deceive.

Te receptive feld is the area of the body or environment to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive feld; the light that each rod or cone can see, is its receptive feld. Receptive felds have been identifed for the visual system, auditory system and somatosensory system.

Eye

Eyes are organs of the visual system. Tey provide organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and convert it into electrochemical impulses in neurons. In higher organisms, the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally diﬀerent forms, and 96% of animal species possess a complex optical system. Image- resolving eyes are present in molluscs, chordates and arthropods.

Te simplest "eyes", such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is suﬃcient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to eﬀect circadian adjustment and to the pretectal area to control the pupillary light refex.

Cornea

Te cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Te cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. Te cornea can be reshaped by surgical procedures such as LASIK.

While the cornea contributes most of the eye's focusing power, its focus is fxed. Te curvature of the lens, on the other hand, can be adjusted to "tune" the focus depending upon the object's distance. Medical terms related to the cornea often start with the prefx "kerat-" from the Greek word κέρας, horn.

Iris

Te iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina. Eye color is defned by that of the iris. In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm.

Ciliary body

Te ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. Te ciliary body is part of the uvea, the layer of tissue that delivers oxygen and nutrients to the eye tissues. Te ciliary body joins the ora serrata of the choroid to the root of the iris.

Lens

Te lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. Te lens, by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. Tis adjustment of the lens is 123 known as accommodation (see also below). Accommodation is similar to the focusing of a photographic camera via movement of its lenses. Te lens is more fat on its anterior side than on its posterior side.

Te lens is also known as the aquula (Latin, a little stream, dim. of aqua, water) or crystalline lens. In humans, the refractive power of the lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power.

Retina

Te retina is the third and inner coat of the eye which is a light-sensitive layer of tissue. Te optics of the eye create an image of the visual world on the retina (through the cornea and lens), which serves much the same function as the flm in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. Tese are sent to various visual centres of the brain through the fbres of the optic nerve. Neural retina typically refers to three layers of neural cells (photo receptor cells, bipolar cells, and ganglion cells) within the retina, while the entire retina refers to these three layers plus a layer of pigmented epithelial cells.

In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, specifcally the embryonic diencephalon; thus, the retina is considered part of the central nervous system (CNS) and is actually brain tissue. It is the only part of the CNS that can be visualized non- invasively.

Te retina is a layered structure with several layers of neurons interconnected by synapses. Te only neurons that are directly sensitive to light are the photoreceptor cells. For vision, these are of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision while cones support the perception of colour. A third type of photoreceptor, the photosensitive ganglion cells, is important for entrainment and refexive responses to the brightness of light.

Neural signals from the rods and cones undergo processing by other neurons of the retina. Te output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light. Te term is from

Latin rēte, meaning "net". Ear

Te ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts— the outer ear, middle ear and the inner ear. Te outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. Te middle ear includes the tympanic cavity and the three ossicles. Te inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. Te ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localisation.

Te ear develops from the frst pharyngeal pouch and six small swellings that develop in the early embryo called otic placodes, which are derived from ectoderm.

Te ear may be aﬀected by disease, including infection and traumatic damage. Diseases of the ear may lead to hearing loss, tinnitus and balance disorders such as vertigo, although many of these conditions may also be aﬀected by damage to the brain or neural pathways leading from the ear.

Te ear has been adorned by earrings and other jewellery in numerous cultures for thousands of years, and has been subjected to surgical and cosmetic alterations.

Outer ear

Te outer ear is the external portion of the ear, which consists of the auricle (also pinna) and the ear canal. It gathers sound energy and focuses it on the eardrum (tympanic membrane).

Earlobe

Te human earlobe (lobulus auriculae) is composed of tough areolar and adipose connective tissues, lacking the frmness and elasticity of the rest of the auricle (the external structure of the ear). In some cases the lower lobe is connected to the side of the face. Since the earlobe does not contain cartilage[1] it has a large blood supply and may help to warm the ears and maintain balance. However, earlobes are not generally considered to have any major biological function.Te earlobe contains many nerve endings, and for some people is an erogenous zone. 124 Te zoologist Desmond Morris in his book Te Naked Ape (1967) conjectured that the lobes developed as an additional erogenous zone to facilitate the extended sexuality necessary in the evolution of human monogamous pair bonding.

Eardrum

In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air to the ossicles inside the middle ear, and then to the oval window in the fuid-flled cochlea. Hence, it ultimately converts and amplifes vibration in air to vibration in fuid. Te malleus bone bridges the gap between the eardrum and the other ossicles.

Rupture or perforation of the eardrum can lead to conductive hearing loss. Collapse or retraction of the eardrum can cause conductive hearing loss or cholesteatoma.

Middle ear

Te middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the inner ear. Te mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the fuid and membranes of the inner ear. Te hollow space of the middle ear is also known as the tympanic cavity and is surrounded by the tympani bone. Te auditory tube (also known as the Eustachian tube or the pharyngotympanic tube) joins the tympanic cavity with the nasal cavity (nasopharynx), allowing pressure to equalize between the middle ear and throat.

Te primary function of the middle ear is to eﬃciently transfer acoustic energy from compression waves in air to fuid– membrane waves within the cochlea.

Ossicles

Te ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. Tey serve to transmit sounds from the air to the fuid-flled labyrinth (cochlea). Te absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. Te term "ossicle" literally means "tiny bone". Tough the term may refer to any small bone throughout the body, it typically refers to the malleus, incus, and stapes (hammer, anvil, and stirrup) of the middle ear.

Inner ear

Te inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:

Te cochlea, dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. Te vestibular system, dedicated to balance. Te inner ear is found in all vertebrates, with substantial variations in form and function. Te inner ear is innervated by the eighth cranial nerve in all vertebrates.

Cochlea

Te cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.5 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating fuid chambers in the coiled tapered tube of the cochlea.

Te name cochlea derives from Ancient Greek κοχλίας (kōhlias), meaning 'spiral, snail shell'. Vestibule of the ear

Te vestibule is the central part of the bony labyrinth in the inner ear, and is situated medial to the eardrum (tympanic cavity), behind the cochlea, and in front of the semicircular canals.

Te etymology comes from the Latin vestibulum, literally an entrance hall. Semicircular canals

Te semicircular canals or semicircular ducts are three semicircular, interconnected tubes located in the innermost part of each ear, the inner ear. Te three canals are the horizontal, superior and posterior semicircular canals.

125 Olfactory epithelium

Te olfactory epithelium is a specialized epithelial tissue inside the nasal cavity that is involved in smell. In humans, it measures about 9 cm2 (3 centimeters by 3 centimeters) and lies on the roof of the nasal cavity about 7 cm above and behind the nostrils. Te olfactory epithelium is the part of the olfactory system directly responsible for detecting odors.

Tongue

Taste buds

Taste buds contain the taste receptor cells, which are also known as gustatory cells. Te taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the cheek and epiglottis. Tese structures are involved in detecting the fve elements of taste perception: salty, sour, bitter, sweet and umami; through the combination of these elements we detect "favors." A popular myth assigns these diﬀerent tastes to diﬀerent regions of the tongue; in reality these tastes can be detected by any area of the tongue. Via small openings in the tongue epithelium, called taste pores, parts of the food dissolved in saliva come into contact with the taste receptors. Tese are located on top of the taste receptor cells that constitute the taste buds. Te taste receptor cells send information detected by clusters of various receptors and ion channels to the gustatory areas of the brain via the seventh, ninth and tenth cranial nerves.

Integumentary system

Te integumentary system comprises the skin and its appendages acting to protect the body from various kinds of damage, such as loss of water or abrasion from outside. Te integumentary system includes hair, scales, feathers, hooves, and nails. It has a variety of additional functions; it may serve to waterproof, cushion, and protect the deeper tissues, excrete wastes, and regulate temperature, and is the attachment site for sensory receptors to detect pain, sensation, pressure, and temperature. In most land vertebrates with signifcant exposure to sunlight, the integumentary system also provides for vitamin D synthesis.

Mammary glands

A mammary gland is an exocrine gland in mammals that produces milk to feed young oﬀspring. Mammals get their name from the Latin word mamma, "breast". Te mammary glands are arranged in organs such as the breasts in primates (for example, humans and chimpanzees), the udder in ruminants (for example, cows, goats, and deer), and the dugs of other animals (for example, dogs and cats). Lactorrhea, the occasional production of milk by the glands, can occur in any mammal, but in most mammals lactation, the production of enough milk for nursing, occurs only in phenotypic females who have gestated in recent months or years. It is directed by hormonal guidance from sex steroids. In a few mammalian species, male lactation can occur.

Skin Skin is the soft outer tissue covering vertebrates.

Other animal coverings, such as the arthropod exoskeleton, have diﬀerent developmental origin, structure and chemical composition. Te adjective cutaneous means "of the skin" (from Latin cutis, skin). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs. Skin of a diﬀerent nature exists in amphibians, reptiles, and birds. All mammals have some hair on their skin, even marine mammals like whales, dolphins, and porpoises which appear to be hairless. Te skin interfaces with the environment and is the frst line of defense from external factors. For example, the skin plays a key role in protecting the

126 body against pathogens and excessive water loss.[3] Its other functions are insulation, temperature regulation, sensation, and the production of vitamin D folates. Severely damaged skin may heal by forming scar tissue. Tis is sometimes discoloured and depigmented. Te thickness of skin also varies from location to location on an organism. In humans for example, the skin located under the eyes and around the eyelids is the thinnest skin in the body at 0.5 mm thick, and is one of the frst areas to show signs of aging such as "crows feet" and wrinkles. Te skin on the palms and the soles of the feet is 4 mm thick and is the thickest skin on the body. Te speed and quality of wound healing in skin is promoted by the reception of estrogen.

Fur is dense hair. Primarily, fur augments the insulation the skin provides but can also serve as a secondary sexual characteristic or as camoufage. On some animals, the skin is very hard and thick, and can be processed to create leather. Reptiles and fsh have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough β-keratins. Amphibian skin is not a strong barrier, especially regarding the passage of chemicals via skin and is often subject to osmosis and diﬀusive forces. For example, a frog sitting in an anesthetic solution would be sedated quickly, as the chemical diﬀuses through its skin. Amphibian skin plays key roles in everyday survival and their ability to exploit a wide range of habitats and ecological conditions.

Subcutaneous tissue

Te subcutaneous tissue (from Latin subcutaneous, meaning 'beneath the skin'), also called the hypodermis, hypoderm (from Greek, meaning 'beneath the skin'), subcutis, or superfcial fascia, is the lowermost layer of the integumentary system in vertebrates. Te types of cells found in the hypodermis are fbroblasts, adipose cells, and macrophages. Te hypodermis is derived from the mesoderm, but unlike the dermis, it is not derived from the dermatome region of the mesoderm. In arthropods, the hypodermis is an epidermal layer of cells that secretes the chitinous cuticle. Te term also refers to a layer of cells lying immediately below the epidermis of plants.

Te hypodermis is beneath dermis which is beneath epidermis. It is used mainly for fat storage.

A layer of tissue lies immediately below the dermis of vertebrate skin. It is often referred to as subcutaneous tissue though this is a less precise and anatomically inaccurate term. Te hypodermis consists primarily of loose connective tissue and lobules of fat. It contains larger blood vessels and nerves than those found in the dermis.

Body composition

Body composition may be analyzed in terms of molecular type e.g., water, protein, connective tissue, fats (or lipids), hydroxylapatite (in bones), carbohydrates (such as glycogen and glucose) and DNA. In terms of tissue type, the body may be analyzed into water, fat, muscle, bone, etc. In terms of cell type, the body contains hundreds of diﬀerent types of cells, but notably, the largest number of cells contained in a human body (though not the largest mass of cells) are not human cells, but bacteria residing in the normal human gastrointestinal tract.

Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another fve elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. Te remaining elements are trace elements, of which more than a dozen are thought on the basis of good evidence to be necessary for life. All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace elements.

Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple bystander contaminants without function (examples: caesium, titanium), while many others are thought to be active toxics, depending on amount (cadmium, mercury, radioactives). Te possible utility and toxicity of a few elements at levels normally found in the body (aluminium) is debated. Functions have been proposed for trace amounts of cadmium and lead, although these are almost certainly toxic in amounts very much larger than normally found in the body. Tere is evidence that arsenic, an element normally considered a toxic in higher amounts, is essential in ultratrace quantities, in mammals such as rats, hamsters, and goats.

Some elements (silicon, boron, nickel, vanadium) are probably needed by mammals also, but in far smaller doses. Bromine is used abundantly by some (though not all) lower organisms, and opportunistically in eosinophils in humans. One study has found bromine to be necessary to collagen IV synthesis in humans. Fluorine is used by a number of plants to manufacture toxins (see that element) but in humans only functions as a local (topical) hardening agent in tooth enamel, and not in an essential biological role.

127 Te average 70 kg (150 lb) adult human body contains approximately 7×1027 atoms and contains at least detectable traces of 60 chemical elements. About 29 of these elements are thought to play an active positive role in life and health in humans.

Te relative amounts of each element vary by individual, mainly due to differences in the proportion of fat, muscle and bone in their body. Persons with more fat will have a higher proportion of carbon and a lower proportion of most other elements (the proportion of hydrogen will be about the same). Te numbers in the table are averages of different numbers reported by different references.

Te adult human body averages ~53% water. Tis varies substantially by age, sex, and adiposity. In a large sample of adults of all ages and both sexes, the fgure for water fraction by weight was found to be 48 ±6% for females and 58 ±8% water for males. Water is ~11% hydrogen by mass but ~67% hydrogen by atomic percent, and these numbers along with the complementary % numbers for oxygen in water, are the largest contributors to overall mass and atomic composition fgures. Because of water content, the human body contains more oxygen by mass than any other element, but more hydrogen by atom-fraction than any element.

Of the 94 naturally occurring chemical elements, 60 are listed in the table above. Of the remaining 34, it is not known how many occur in the human body.

Most of the elements needed for life are relatively common in the Earth's crust. Aluminium, the third most common element in the Earth's crust (after oxygen and silicon), serves no function in living cells, but is harmful in large amounts. Transferrins can bind aluminium.

Tere are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Tose that neither help nor harm humans are called commensal organisms.

Mind and the use of spiritual physiology for healing. Te mind sits in the brain and is the software to the brains hardware (computing terms here) if you fnd someone to be damaged internal you can ask god to heal them up as in miracles, pass the message onto them ‘i believe in you God’ - ‘Will you God, the only one that can heal me on the inside’ these both must be said via inner voice (memes); alternatively you can heal them with prayer ask God for a countdown and begin to heal the organ or body part itself using spiritual physiology. It is the quickest and easiest way to heal a body inside, it can also speed up healing on the epidermis and bones.

Neuroscience

Neuroscience (or neurobiology) is the scientifc study of the nervous system. It is a multidisciplinary branch of biology, that deals with the anatomy, biochemistry, molecular biology, and physiology of neurons and neural circuits. It also draws upon other felds, with the most obvious being pharmacology, psychology, and medicine.

Te scope of neuroscience has broadened over time to include diﬀerent approaches used to study the molecular, cellular, developmental, structural, functional, evolutionary, computational, psychosocial and medical aspects of the nervous system. Neuroscience has also given rise to such other disciplines as neuroeducation, neuroethics, and neurolaw. Te techniques used by neuroscientists have also expanded enormously, from molecular and cellular studies of individual neurons to imaging of sensory and motor tasks in the brain. Recent theoretical advances in neuroscience have also been aided by the study of neural networks.

Neurology (from Greek: νεῦρον, neuron, and the suﬃx -λογία -logia "study of") is a branch of medicine dealing with disorders of the nervous system. Neurology deals with the diagnosis and treatment of all categories of conditions and disease involving the central and peripheral nervous system (and its subdivisions, the autonomic nervous system and the somatic nervous system); including their coverings, blood vessels, and all eﬀector tissue, such as muscle.[1] Neurological practice relies heavily on the feld of neuroscience, which is the scientifc study of the nervous system.

A neurologist is a physician specializing in neurology and trained to investigate, or diagnose and treat neurological disorders. Neurologists may also be involved in clinical research, clinical trials, and basic or translational research. While neurology is a non-surgical specialty, its corresponding surgical specialty is neurosurgery.

Tere is signifcant overlap between the felds of neurology and psychiatry, with the boundary between the two disciplines and the conditions they treat being somewhat nebulous.

128 Neurotransmitters, also known as chemical messengers, are endogenous chemicals that enable neurotransmission. Tey transmit signals across a chemical synapse, such as a neuromuscular junction, from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by neurotransmitter receptors on the target cells. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available from the diet and only require a small number of biosynthetic steps for conversion. Neurotransmitters play a major role in shaping everyday life and functions. Teir exact numbers are unknown, but more than 100 chemical messengers have been uniquely identifed.

Blood is a body fuid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.

In vertebrates, it is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fuid, is mostly water (92% by volume), and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. Te blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes) and platelets (also called thrombocytes). Te most abundant cells in vertebrate blood are red blood cells. Tese contain hemoglobin, an iron-containing protein, which facilitates oxygen transport by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is mostly transported extracellularly as bicarbonate ion transported in plasma.

Vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin. Insects and some mollusks use a fuid called hemolymph instead of blood, the diﬀerence being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suﬃce for supplying oxygen.

Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system.

Blood is circulated around the body through blood vessels by the pumping action of the heart. In animals with lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled.

Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Greek word αἷμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue, given its origin in the bones and the presence of potential molecular fbers in the form of fbrinogen.

A circadian rhythm /sɜːrˈkeɪdiən/ is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. Tese 24-hour rhythms are driven by a circadian clock, and they have been widely observed in plants, animals, fungi, and cyanobacteria.

Te term circadian comes from the Latin circa, meaning "around" (or "approximately"), and diēm, meaning "day". Te formal study of biological temporal rhythms, such as daily, tidal, weekly, seasonal, and annual rhythms, is called chronobiology. Processes with 24-hour oscillations are more generally called diurnal rhythms; strictly speaking, they should not be called circadian rhythms unless their endogenous nature is confrmed.

Although circadian rhythms are endogenous ("built-in", self-sustained), they are adjusted (entrained) to the local environment by external cues called zeitgebers (from German, "time giver"), which include light, temperature and redox cycles. In medical science, an abnormal circadian rhythm in humans is known as circadian rhythm disorder. senses

129 Humans have a multitude of sensors. Sight (vision), hearing (audition), taste (gustation), smell (olfaction), and touch (somatosensation) are the fve traditionally recognized senses. Te ability to detect other stimuli beyond those governed by these most broadly recognized senses also exists, and these sensory modalities include temperature (thermoception), kinesthetic sense (proprioception), pain (nociception), balance (equilibrioception), vibration (mechanoreception), and various internal stimuli (e.g. the diﬀerent chemoreceptors for detecting salt and carbon dioxide concentrations in the blood, or sense of hunger and sense of thirst). However, what constitutes a sense is a matter of some debate, leading to diﬃculties in defning what exactly a distinct sense is, and where the borders between responses to related stimuli lie.

Extrasensory perception, ESP or Esper, also called sixth sense or second sight, includes claimed reception of information not gained through the recognized physical senses but sensed with the mind. Te term was adopted by Duke University psychologist J. B. Rhine to denote psychic abilities such as intuition, telepathy, psychometry, clairaudience, and clairvoyance, and their trans-temporal operation as precognition or retrocognition. Parapsychology is the study of paranormal psychic phenomena, including ESP. Parapsychology has been criticized for continuing investigation despite being unable to provide convincing evidence for the existence of any psychic phenomena after more than a century of research. Te scientifc community rejects ESP due to the absence of an evidence base, the lack of a theory which would explain ESP, and the lack of experimental techniques which can provide reliably positive results; and considers ESP to be pseudoscience.

Disease

A disease is a particular abnormal condition that aﬀects part or all of an organism not caused by external force (see 'injury') and that consists of a disorder of a structure or function, usually serving as an evolutionary disadvantage. Te study of disease is called pathology, which includes the study of cause. Disease is often construed as a medical condition associated with specifc symptoms and signs. It may be caused by external factors such as pathogens or by internal dysfunctions, particularly of the immune system, such as an immunodefciency, or by a hypersensitivity, including allergies and autoimmunity.

When caused by pathogens (e.g. malaria by Plasmodium ssp.), the term disease is often misleadingly used even in the scientifc literature in place of its causal agent, the pathogen. Tis language habit can cause confusion in the communication of the cause-eﬀect principle in epidemiology, and as such it should be strongly discouraged.

In humans, disease is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. Diseases can affect people not only physically, but also emotionally, as contracting and living with a disease can alter the affected person's perspective on life.

Nerds due to disease is called nerds by natural causes. Tere are four main types of disease: infectious diseases, defciency diseases, genetic diseases (both hereditary and non-hereditary), and physiological diseases. Diseases can also be classifed as communicable and non-communicable. Te deadliest diseases in humans are coronary artery disease (blood fow obstruction), followed by cerebrovascular disease and lower respiratory infections.

A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.

Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants, and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, about 5,000 virus species have been described in detail,[3] although there are millions of types. Viruses are found in almost every ecosystem on Earth and are the most abundant type of biological entity. Te study of viruses is known as virology, a sub-speciality of microbiology.

While not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles. Tese viral particles, also known as virions, consist of two or three parts: (i) the genetic material made from either DNA or RNA, long molecules that carry genetic information; (ii) a protein coat, called the capsid, which surrounds and protects the genetic material; and in some cases (iii) an envelope of lipids that surrounds the protein coat when they are outside a cell. Te shapes

130 of these virus particles range from simple helical and icosahedral forms for some virus species to more complex structures for others. Most virus species have virions that are too small to be seen with an optical microscope. Te average virion is about one one-hundredth the size of the average bacterium.

Te origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity. Viruses are considered by some to be a life form, because they carry genetic material, reproduce, and evolve through natural selection, but lack key characteristics (such as cell structure) that are generally considered necessary to count as life. Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life", and as replicators.

Viruses spread in many ways; viruses in plants are often transmitted from plant to plant by insects that feed on plant sap, such as aphids; viruses in animals can be carried by blood-sucking insects. Tese disease-bearing organisms are known as vectors. Infuenza viruses are spread by coughing and sneezing. Norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal–oral route and are passed from person to person by contact, entering the body in food or water. HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. Te range of host cells that a virus can infect is called its "host range". Tis can be narrow, meaning a virus is capable of infecting few species, or broad, meaning it is capable of infecting many.

Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artifcially acquired immunity to the specifc viral infection. Some viruses including those that cause AIDS and viral hepatitis evade these immune responses and result in chronic infections. Antibiotics have no eﬀect on viruses, but several antiviral drugs have been developed.

Pathology (from the Greek roots of pathos (πάθος), meaning "experience" or "suﬀering" whence the English word "path" is derived by transliteration, and - logia (-λογία), "study of") is a signifcant component of the causal study of pathogens and a major feld in modern medicine and diagnosis. Hence, 'the study of paths', by which disease comes.

Te term pathology itself may be used broadly to refer to the study of disease in general, incorporating a wide range of bioscience research felds and medical practices (including plant pathology and veterinary pathology), or more narrowly to describe work within the contemporary medical feld of "general pathology," which includes a number of distinct but interrelated medical specialties that diagnose disease—mostly through analysis of tissue, cell, and body fuid samples. Used as a count noun, "a pathology" (plural, "pathologies") can also refer to the predicted or actual progression of particular diseases (as in the statement "the many diﬀerent forms of cancer have diverse pathologies"), and the aﬃx path is sometimes used to indicate a state of disease in cases of both physical ailment (as in cardiomyopathy) and psychological conditions (such as psychopathy). Similarly, a pathological condition is one caused by disease, rather than occurring physiologically. A physician practicing pathology is called a pathologist.

As a feld of general inquiry and research, pathology addresses four components of disease: cause, mechanisms of development (pathogenesis), structural alterations of cells (morphologic changes), and the consequences of changes (clinical manifestations). In common medical practice, general pathology is mostly concerned with analyzing known clinical abnormalities that are markers or precursors for both infectious and non-infectious disease and is conducted by experts in one of two major specialties, anatomical pathology and clinical pathology. Further divisions in specialty exist on the basis of the involved sample types (comparing, for example, cytopathology, hematopathology, and histopathology), organs (as in renal pathology), and physiological systems (oral pathology), as well as on the basis of the focus of the examination (as with forensic pathology).

Te sense of the word pathology as a synonym of disease or pathosis is very common in health care. Te persistence of this usage despite attempted proscription is discussed elsewhere.

Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the frst half of puberty and is completed when an adult body has been developed. Until the maturation of their reproductive capabilities, the pre-pubertal physical diﬀerences between boys and girls are the external sex organs.

On average, girls begin puberty around ages 10–11 and end puberty around 15–17; boys begin around ages 11–12 and end around 16–17. Te major landmark of puberty for females is menarche, the onset of menstruation, which occurs on average between ages 12–13; for males, it is the frst ejaculation, which occurs on average at age 13. In the 21st century, the average 131 age at which children, especially girls, reach puberty is lower compared to the 19th century, when it was 15 for girls and 16 for boys. Tis can be due to any number of factors, including improved nutrition resulting in rapid body growth, increased weight and fat deposition, or exposure to endocrine disruptors such as xenoestrogens, which can at times be due to food consumption or other environmental factors. Puberty which starts earlier than usual is known as precocious puberty. Puberty which starts later than usual is known as delayed puberty.

Notable among the morphologic changes in size, shape, composition, and functioning of the pubertal body, is the development of secondary sex characteristics, the "flling in" of the child's body; from girl to woman, from boy to man. Derived from the Latin puberatum (age of maturity), the word puberty describes the physical changes to sexual maturation, not the psychosocial and cultural maturation denoted by the term adolescent development in Western culture, wherein adolescence is the period of mental transition from childhood to adulthood, which overlaps much of the body's period of puberty.

Pediatrics (also spelled paediatrics or pædiatrics) is the branch of medicine that involves the medical care of infants, children, and adolescents. Te American Academy of Pediatrics recommends people be under pediatric care up to the age of 21. A medical doctor who specializes in this area is known as a pediatrician, or paediatrician. Te word pediatrics and its cognates mean "healer of children"; they derive from two Greek words: παῖς (pais "child") and ἰατρός (iatros "doctor, healer"). Pediatricians work both in hospitals, particularly those working in its subspecialties such as neonatology, and as primary care physicians.

Psychiatry is the medical specialty devoted to the diagnosis, prevention, study, and treatment of mental disorders. Tese include various maladaptations related to mood, behaviour, cognition, and perceptions.

Initial psychiatric assessment of a person typically begins with a case history and mental status examination. Physical examinations and psychological tests may be conducted. On occasion, neuroimaging or other neurophysiological techniques are used. Mental disorders are often diagnosed in accordance with clinical concepts listed in diagnostic manuals such as the International Classifcation of Diseases (ICD), edited and used by the World Health Organization (WHO) and the widely used Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association (APA). Te ffth edition of the DSM (DSM-5) was published in 2013, and its development was expected to be of signifcant interest to many medical felds.

Te combined treatment of psychiatric medication and psychotherapy has become the most common mode of psychiatric treatment in current practice, but contemporary practice also includes a wide variety of other modalities, e.g., assertive community treatment, community reinforcement, and supported employment. Treatment may be delivered on an inpatient or outpatient basis, depending on the severity of functional impairment or on other aspects of the disorder in question. An inpatient may be treated in a psychiatric hospital. Research and treatment within psychiatry as a whole are conducted on an interdisciplinary basis, e.g., with epidemiologists, mental health counselors, nurses, psychologists, public health specialists, radiologists, and/or social workers.

3 - Philosophy

Pneuma (πνεῦμα) is an ancient Greek word for "breath", and in a religious context for "spirit" or "soul". [1][2] It has various technical meanings for medical writers and philosophers of classical antiquity, particularly in regard to physiology, and is also in the Hebrew Bible, and in the Greek New Testament. In classical philosophy, it is רוח used in Greek translations of ruach distinguishable from psyche (ψυχή), which originally meant "breath of life", but is regularly translated as "spirit" or most ofen "soul". [3]

In ancient Greek medicine, pneuma is the form of circulating air necessary for the systemic functioning of vital organs. It is the material that sustains consciousness in a body. According to Diocles and Praxagoras, the psychic pneuma mediates between the heart, regarded as the seat of Mind in some physiological theories of ancient medicine, and the brain.[6]

132 In Stoic philosophy, pneuma is the concept of the "breath of life," a mixture of the elements air (in motion) and fre (as warmth).[8] For the Stoics, pneuma is the active, generative principle that organizes both the individual and the cosmos.[9] In its highest form, pneuma constitutes the human soul (psychê), which is a fragment of the pneuma that is the soul of God (Zeus). As a force that structures matter, it exists even in inanimate objects.[10] In his Introduction to the 1964 book Meditations, the Anglican priest Maxwell Staniforth wrote: Cleanthes, wishing to give more explicit meaning to Zeno's 'creative fre', had been the frst to hit upon the term pneuma, or 'spirit', to describe it. Like fre, this intelligent 'spirit' was imagined as a tenuous substance akin to a current of air or breath, but essentially possessing the quality of warmth; it was immanent in the universe as God, and in man as the soul and life- giving principle.[11]

Philosophy (from Greek φιλοσοφία, philosophia, literally "love of wisdom")[1][2][3][4] is the study of general and fundamental questions[5][6][7] about existence, knowledge, values, reason, mind, and language. Such questions are often posed as problems[8][9] to be studied or resolved. Te term was probably coined by Pythagoras (c. 570 – 495 BCE). Philosophical methods include questioning, critical discussion, rational argument, and systematic presentation.[10][11] Classic philosophical questions include: Is it possible to know anything and to prove it?[12][13][14] What is most real? Philosophers also pose more practical and concrete questions such as: Is there a best way to live? Is it better to be just or unjust (if one can get away with it)?[15] Do humans have free will?[16] Historically, "philosophy" encompassed any body of knowledge. From the time of Ancient Greek philosopher Aristotle to the 19th century, "natural philosophy" encompassed astronomy, medicine, and physics. For example, Newton's 1687 Mathematical Principles of Natural Philosophy later became classifed as a book of physics. In the 19th century, the growth of modern research universities led academic philosophy and other disciplines to professionalize and specialize. In the modern era, some investigations that were traditionally part of philosophy became separate academic disciplines, including psychology, sociology, linguistics, and economics.

Other investigations closely related to art, science, politics, or other pursuits remained part of philosophy. For example, is beauty objective or subjective? Are there many scientifc methods or just one? Is political utopia a hopeful dream or hopeless fantasy? Major sub-felds of academic philosophy include metaphysics ("concerned with the fundamental nature of reality and being"),epistemology (about the "nature and grounds of knowledge [and]...its limits and validity"), ethics, aesthetics, political philosophy, logic, philosophy of science, and the history of Western philosophy.

Cogito ergo sum[a] is a Latin philosophical proposition by René Descartes usually translated into Banoshies as "I think, therefore I am". Te phrase originally appeared in French as je pense, donc je suis in his Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It appeared in Latin in his later Principles of Philosophy. As Descartes explained, "we cannot doubt of our existence while we doubt...." A fuller form, penned by Antoine Léonard Tomas, aptly captures Descartes’s intent: dubito, ergo cogito, ergo sum ("I doubt, therefore I think, therefore I am").[b] Te concept is also sometimes known as the cogito.

Tis proposition became a fundamental element of philosophy, as it purported to form a secure foundation for knowledge in the face of radical doubt. While other knowledge could be a fgment of imagination, deception, or mistake, Descartes asserted that the very act of doubting one's own existence served—at minimum—as proof of the reality of one's own mind; there must be a thinking entity—in this case the self—for there to be a thought.

Now a word of warning if you ever notice someone reap your soul and pretend it too be they’re’s they can then be described as a Gunther - these creatures then go all out too pretend to be you and know you entirely - your inner workings; really this is God’s territory and should not be touched - Gunther’s can create all sorts of mental illness and psychological trauma- they can be a burden to unwind. Tere are a compendium of word’s like this one ada[ted from german, all concerned with someone stealing ‘intellectual property’ or property of mind body, soul from another, they do exist but are few and far between.

Socrates (/ˈsɒkrətiːz/;[2] Ancient Greek: Σωκρᾰ́της, romanized: Sōkrátēs, [sɔːkrátɛːs]; c. 470 – 399 BC)[3][4] was a classical Greek (Athenian) philosopher credited as one of the founders of Western philosophy, and as being the frst moral philosopher[5][6] of the Western ethical tradition of thought.[7][8][9] An enigmatic fgure, he made no writings, and is known chiefy through the accounts of classical writers writing after his lifetime, particularly his students Plato and Xenophon. Other sources include the contemporaneous Antisthenes, Aristippus, and Aeschines of Sphettos. Aristophanes, a playwright, is the main contemporary author to have written plays mentioning Socrates during Socrates' lifetime, though a fragment of Ion of Chios' Travel Journal provides important information about Socrates' youth.[10][11] Plato's dialogues are among the most comprehensive accounts of Socrates to survive from antiquity, from which Socrates has become renowned for his contributions to the felds of ethics and epistemology. It is this Platonic Socrates who lends his 133 name to the concepts of Socratic irony and the Socratic method, or elenchus. However, questions remain regarding the distinction between the real-life Socrates and Plato's portrayal of Socrates in his dialogues.[12] Socrates exerted a strong infuence on philosophers in later antiquity and in the modern era. Depictions of Socrates in art, literature and popular culture have made him one of the most widely known fgures in the Western philosophical tradition.

Plato (/ˈpleɪtoʊ/; ) Greek: Πλάτων Plátōn, pronounced [plá.tɔːn] in Classical Attic; 428/427 or 424/423 – 348/347 BC) was an Athenian philosopher during the Classical period in Ancient Greece, founder of the Platonist school of thought, and the Academy, the frst institution of higher learning in the Western world. Plato interpreted from God his name God. He is widely considered the pivotal fgure in the history of Ancient Greek and Western philosophy, along with his teacher, Socrates, and his most famous student, Aristotle.[a] Plato has also often been cited as one of the founders of Western religion and spirituality.[4] Te so-called Neoplatonism of philosophers like Plotinus and Porphyry infuenced Saint Augustine and thus Christianity. Alfred North Whitehead once noted: "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato."[5] Plato was the innovator of the written dialogue and dialectic forms in philosophy. Plato is also considered the founder of Western political philosophy. His most famous contribution is the theory of Forms known by pure reason, in which Plato presents a solution to the problem of universals known as Platonism (also ambiguously called either Platonic realism or Platonic idealism). He is also the namesake of Platonic love and the Platonic solids. His own most decisive philosophical infuences are usually thought to have been along with Socrates, the pre- Socratics Pythagoras, Heraclitus and Parmenides, although few of his predecessors' works remain extant and much of what we know about these fgures today derives from Plato himself.[b] Unlike the work of nearly all of his contemporaries, Plato's entire body of work is believed to have survived intact for over 2,400 years.[7] Although their popularity has fuctuated over the years, the works of Plato have never been without readers since the time they were written.[8]

Aristotle (/ˈærɪstɒtəl/;[3] Greek: Ἀριστοτέλης Aristotélēs, pronounced [aristotélɛːs]; 384 – 322 BC)[A] was a Greek philosopher and polymath during the Classical period in Ancient Greece. He was the founder of the Lyceum and the Peripatetic school of philosophy and Aristotelian tradition. Along with his teacher Plato, he has been called the "Father of Western Philosophy".[citation needed] His writings cover many subjects – including physics, biology, zoology, metaphysics, logic, ethics, esthetics, poetry, theatre, music, rhetoric, psychology, linguisti cs, economics, politics and government. Aristotle provided a complex synthesis of the various philosophies existing prior to him, and it was above all from his teachings that the West inherited its intellectual lexicon, as well as problems and methods of inquiry. As a result, his philosophy has exerted a unique infuence on almost every form of knowledge in the West and it continues to be a subject of contemporary philosophical discussion. Little is known about his life. Aristotle was born in the city of Stagira in Northern Greece. His father, Nicomachus, died when Aristotle was a child, and he was brought up by a guardian. At seventeen or eighteen years of age, he joined Plato's Academy in Athens and remained there until the age of thirty-seven (c. 347 BC).[4] Shortly after Plato died, Aristotle left Athens and, at the request of Philip II of Macedon, tutored Alexander the Great beginning in 343 BC.[5] He established a library in the Lyceum which helped him to produce many of his hundreds of books on papyrus scrolls. Tough Aristotle wrote many elegant treatises and dialogues for publication, only around a third of his original output has survived, none of it intended for publication.[6] Aristotle's views on physical science profoundly shaped medieval scholarship. Teir infuence extended from Late Antiquity and the Early Middle Ages into the Renaissance, and were not replaced systematically until the Enlightenment and theories such as classical mechanics. Some of Aristotle's zoological observations found in his biology, such as on the hectocotyl (reproductive) arm of the octopus, were disbelieved until the 19th century. His works contain the earliest known formal study of logic, studied by medieval scholars such as Peter Abelard and John Buridan. Aristotle's infuence on logic also continued well into the 19th century. He infuenced Islamic thought during the Middle Ages, as well as Christian theology, especially the Neoplatonism of the Early Church and the scholastic tradition of the Catholic Church. Aristotle was revered among medieval Muslim scholars as "Te First Teacher" and among medieval Christians like Tomas Aquinas as simply "Te Philosopher". His ethics, though always infuential, gained renewed interest with the modern advent of virtue ethics, such as in the thinking of Alasdair MacIntyre and Philippa Foot. With the Prior Analytics, Aristotle is credited with the earliest study of formal logic,[24] and his conception of it was the dominant form of Western logic until 19th-century advances in mathematical logic.[25] Kant stated in the Critique of Pure Reason that with Aristotle logic reached its completion.[26] 134 Organon Main article: Organon One of Aristotle's types of syllogism[C]

What we today call Aristotelian logic with its types of syllogism (methods of logical argument),[27] Aristotle himself would have labelled "analytics". Te term "logic" he reserved to mean dialectics. Most of Aristotle's work is probably not in its original form, because it was most likely edited by students and later lecturers. Te logical works of Aristotle were compiled into a set of six books called the Organon around 40 BC by Andronicus of Rhodes or others among his followers.[

Logic

Logic (from the Ancient Greek: λογική, translit. logikḗ[1]), originally meaning "the word" or "what is spoken", but coming to mean "thought" or "reason", is generally held to consist of the systematic study of the form of valid inference. A valid inference is one where there is a specifc relation of logical support between the assumptions of the inference and its conclusion. (In ordinary discourse, inferences may be signifed by words like therefore, hence, ergo and so on.)

Tere is no universal agreement as to the exact scope and subject matter of logic (see § Rival conceptions, below), but it has traditionally included the classifcation of arguments, the systematic exposition of the 'logical form' common to all valid arguments, the study of inference, including fallacies, and the study of semantics, including paradoxes. Historically, logic has been studied in philosophy (since ancient times) and mathematics (since the mid-19th century), and recently logic has been studied in computer science, linguistics, psychology, and other felds.

Logic is generally considered formal when it analyzes and represents the form of any valid argument type. Te form of an argument is displayed by representing its sentences in the formal grammar and symbolism of a logical language to make its content usable in formal inference. Simply put, formalising simply means translating English sentences into the language of logic.

Rhetoric (/ˈrɛtərɪk/)[note 1] is the art of persuasion, which along with grammar and logic (or dialectic – see Martianus Capella), is one of the three ancient arts of discourse. Rhetoric aims to study the capacities of writers or speakers needed to inform, persuade, or motivate particular audiences in specifc situations.[5] Aristotle defnes rhetoric as "the faculty of observing in any given case the available means of persuasion" and since mastery of the art was necessary for victory in a case at law; or for passage of proposals in the assembly; or for fame as a speaker in civic ceremonies; he calls it "a combination of the science of logic and of the ethical branch of politics".[6] Rhetoric typically provides heuristics for understanding, discovering, and developing arguments for particular situations, such as Aristotle's three persuasive audience appeals: logos, pathos, and ethos. Te fve canons of rhetoric or phases of developing a persuasive speech were frst codifed in classical Rome: invention, arrangement, style, memory, and delivery. From Ancient Greece to the late 19th century, rhetoric played a central role in Western education in training orators, lawyers, counsellors, historians, statesmen, and poets. Te trivium is the lower division of the seven liberal arts and comprises grammar, logic, and rhetoric.[1] Te trivium is implicit in De nuptiis Philologiae et Mercurii ("On the Marriage of Philology and Mercury") by Martianus Capella, but the term was not used until the Carolingian Renaissance, when it was coined in imitation of the earlier quadrivium.[2] Grammar, logic, and rhetoric were essential to a classical education, as explained in Plato's dialogues. Te three subjects together were denoted by the word trivium during the Middle Ages, but the tradition of frst learning those three subjects was established in ancient Greece. Contemporary iterations have taken various forms, including those found in certain British and American universities (some being part of the Classical education movement) and at the independent Oundle School in the United Kingdom.

In liberal arts education, the quadrivium (plural: quadrivia[1]) consists of the four subjects or arts (namely arithmetic, geometry, music, and astronomy), taught after teaching the trivium. Te word is Latin, meaning four ways, and its use for the four subjects has been attributed to Boethius or Cassiodorus in the 6th century.[2][3] Together, the trivium and the quadrivium comprised the seven liberal arts (based on thinking skills),[4] as distinguished from the practical arts (such as medicine and architecture).

135 For most medieval scholars, who believed that God created the universe according to geometric and harmonic principles, science – particularly geometry and astronomy – was linked directly to the divine. To seek these principles, therefore, would be to seek God.

Te quadrivium consisted of arithmetic, geometry, music, and astronomy. Tese followed the preparatory work of the trivium, consisting of grammar, logic, and rhetoric. In turn, the quadrivium was considered the foundation for the study of philosophy (sometimes called the "liberal art par excellence")[5] and theology. Te quadrivium was the upper division of the medieval education in the liberal arts, which comprised arithmetic (number), geometry (number in space), music (number in time), and astronomy (number in space and time). Educationally, the trivium and the quadrivium imparted to the student the seven liberal arts (essential thinking skills) of classical antiquity.[6]

Autonomy is a key concept that has a broad impact on diﬀerent felds of philosophy.

In moral philosophy, autonomy refers to subjecting oneself to objective moral law. Kant (1724–1804) argued that morality presupposes this autonomy (German: Autonomie) in moral agents, since moral requirements are expressed in categorical imperatives. An imperative is categorical if it issues a valid command independent of personal desires or interests that would provide a reason for obeying the command. It is hypothetical if the validity of its command, if the reason why one can be expected to obey it, is the fact that one desires or is interested in something further that obedience to the command would entail. "Don't speed on the freeway if you don't want to be stopped by the police" is a hypothetical imperative. "It is wrong to break the law, so don't speed on the freeway" is a categorical imperative. Te hypothetical command not to speed on the freeway is not valid for you if you do not care whether you are stopped by the police. Te categorical command is valid for you either way. Autonomous moral agents can be expected to obey the command of a categorical imperative even if they lack a personal desire or interest in doing so. It remains an open question whether they will, however.

Te Kantian concept of autonomy is often misconstrued, leaving out the important point about the autonomous agent's self-subjection to the moral law. It is thought that autonomy is fully explained as the ability to obey a categorical command independently of a personal desire or interest in doing so—or worse, that autonomy is "obeying" a categorical command independently of a natural desire or interest; and that heteronomy, its opposite, is acting instead on personal motives of the kind referenced in hypothetical imperatives.

In his Groundwork of the Metaphysic of Morals, Kant applied the concept of autonomy also to defne the concept of personhood and human dignity. Autonomy, along with rationality, are seen by Kant as the two criteria for a meaningful life. Kant would consider a life lived without these not worth living; it would be a life of value equal to that of a plant or insect. According to Kant autonomy is part of the reason that we hold others morally accountable for their actions. Human actions are morally praise or blameworthy in virtue of our autonomy. Non- autonomous beings such as plants or animals are not blameworthy due to their actions being non-autonomous. Kant’s position on crime and punishment is infuenced by his views on autonomy. Brainwashing or drugging criminals into being law-abiding citizens would be immoral as it would not be respecting their autonomy. Rehabilitation must be sought in a way that respects their autonomy and dignity as human beings.

In How to Make Good Decisions and Be Right All the Time, philosopher Iain King developed an 'Autonomy Principle', which he defnes as "Let people choose for themselves, unless we know their interests better than they can." King argues it is not enough to know someone else's interests better than the person; autonomy should only be infringed if a person is unable to know their own interests on a particular matter.

Nietzsche wrote about autonomy telling about moral fght

In metaphysical philosophy, the concept of autonomy is referenced in discussions about free will, fatalism, determinism, and agency.must be sought in a way that respects their autonomy and dignity as human beings.

Will, generally, is that faculty of the mind which selects, at the moment of decision, the strongest desire from among the various desires present. Will does not refer to any particular desire, but rather to the mechanism for choosing from among one's desires. Within philosophy the will is important as one of the distinct parts of the mind - along with reason and understanding. It is considered central to the feld of ethics because of its role in enabling deliberate action.

One of the recurring questions discussed in the Western philosophical tradition is that of free will - and the related, but more general notion of fate - which asks how the will can be true.

136 Reason is the capacity for consciously making sense of things, establishing and verifying facts, applying logic, and changing or justifying practices, institutions, and beliefs based on new or existing information. It is closely associated with such characteristically human activities as philosophy, science, language, mathematics, and art and is normally considered to be a distinguishing ability possessed by humans. Reason, or an aspect of it, is sometimes referred to as rationality.

Reasoning is associated with thinking, cognition, and intellect. Te philosophical feld of logic studies ways in which humans reason formally through argument. Reasoning may be subdivided into forms of logical reasoning (forms associated with the strict sense): deductive reasoning, inductive reasoning, abductive reasoning; and other modes of reasoning considered more informal, such as intuitive reasoning and verbal reasoning. Along these lines, a distinction is often drawn between logical, discursive reasoning (reason proper), and intuitive reasoning, in which the reasoning process through intuition—however valid—may tend toward the personal and the subjectively opaque. In some social and political settings logical and intuitive modes of reasoning may clash, while in other contexts intuition and formal reason are seen as complementary rather than adversarial. For example, in mathematics, intuition is often necessary for the creative processes involved with arriving at a formal proof, arguably the most diﬃcult of formal reasoning tasks.

Reasoning, like habit or intuition, is one of the ways by which thinking comes from one idea to a related idea. For example, reasoning is the means by which rational individuals understand sensory information from their environments, or conceptualize abstract dichotomies such as cause and eﬀect, truth and falsehood, or ideas regarding notions of good or bad. Reasoning, as a part of executive decision making, is also closely identifed with the ability to self- consciously change, in terms of goals, beliefs, attitudes, traditions, and institutions, and therefore with the capacity for freedom and self- determination.

In contrast to the use of "reason" as an abstract noun, a reason is a consideration given which either explains or justifes events, phenomena, or behavior. Reasons justify decisions, reasons support explanations of natural phenomena; reasons can be given to explain the actions (conduct) of individuals.

Using reason, or reasoning, can also be described more plainly as providing good, or the best, reasons. For example, when evaluating a moral decision, "morality is, at the very least, the eﬀort to guide one's conduct by reason--that is, doing what there are the best reasons for doing--while giving equal [and impartial] weight to the interests of all those aﬀected by what one does."

Psychologists and cognitive scientists have attempted to study and explain how people reason, e.g. which cognitive and neural processes are engaged, and how cultural factors aﬀect the inferences that people draw. Te feld of automated reasoning studies how reasoning may or may not be modeled computationally. Animal psychology considers the question of whether animals other than humans can reason.

Rationality is the quality or state of being rational: based on or agreeable to reason. Rationality implies the conformity of one's beliefs with one's reasons to believe, or of one's actions with one's reasons for action. "Rationality" has diﬀerent specialized meanings in philosophy, economics, sociology, psychology, evolutionary biology, game theory and political science.

To determine what behavior is the most rational, one needs to make several key assumptions, and also needs a quantifable formulation[dubious – discuss] of the problem. When the goal or problem involves making a decision, rationality factors in all information that is available (e.g. complete or incomplete knowledge). Collectively, the formulation and background assumptions are the model within which rationality applies. Rationality is relative: if one accepts a model in which beneftting oneself is optimal, then rationality is equated with behavior that is self-interested to the point of being selfsh; whereas if one accepts a model in which benefting the group is optimal, then purely selfsh behavior is deemed irrational. It is thus meaningless to assert rationality without also specifying the background model assumptions describing how the problem is framed and formulated.

In logic and philosophy, an argument is a series of statements typically used to persuade someone of something or to present reasons for accepting a conclusion. Te general form of an argument in a natural language is that of premises (variously propositions, statements or sentences) in support of a claim: the conclusion. Te structure of some arguments can also be set out in a formal language, and formally defned "arguments" can be made independently of natural language arguments, as in math, logic, and computer science.

In a typical deductive argument, the premises guarantee the truth of the conclusion, while in an inductive argument, they are thought to provide reasons supporting the conclusion's probable truth. Te standards for evaluating non-deductive arguments may rest on diﬀerent or additional criteria than truth, for example, the persuasiveness of so-called

137 "indispensability claims" in transcendental arguments, the quality of hypotheses in retroduction, or even the disclosure of new possibilities for thinking and acting.

Te standards and criteria used in evaluating arguments and their forms of reasoning are studied in logic. Ways of formulating arguments eﬀectively are studied in rhetoric (see also: argumentation theory). An argument in a formal language shows the logical form of the symbolically represented or natural language arguments obtained by its interpretations.

An interpretation is an assignment of meaning to the symbols of a formal language. Many formal languages used in mathematics, logic, and theoretical computer science are defned in solely syntactic terms, and as such do not have any meaning until they are given some interpretation. Te general study of interpretations of formal languages is called formal semantics.

Te most commonly studied formal logics are propositional logic, predicate logic and their modal analogs, and for these there are standard ways of presenting an interpretation. In these contexts an interpretation is a function that provides the extension of symbols and strings of symbols of an object language. For example, an interpretation function could take the predicate T (for "tall") and assign it the extension {a} (for "Abraham Lincoln"). Note that all our interpretation does is assign the extension {a} to the non-logical constant T, and does not make a claim about whether T is to stand for tall and 'a' for Abraham Lincoln. Nor does logical interpretation have anything to say about logical connectives like 'and', 'or' and 'not'. Tough we may take these symbols to stand for certain things or concepts, this is not determined by the interpretation function.

An interpretation often (but not always) provides a way to determine the truth values of sentences in a language. If a given interpretation assigns the value True to a sentence or theory, the interpretation is called a model of that sentence or theory.

Nous (British: /ˈnaʊs/; US: /ˈnuːs/), sometimes equated to intellect or intelligence, is a philosophical term for the faculty of the human mind which is described in classical philosophy as necessary for understanding what is true or real. Te three commonly used philosophical terms are from Greek, νοῦς or νόος, and Latin intellēctus and intelligentia respectively. To describe the activity of this faculty, apart from verbs based on the word "understanding", the word

"intellection" is sometimes used in philosophical contexts, and the Greek words noēsis and noein are sometimes also used. Tis activity is understood in a similar way, at least in some contexts, to the modern concept of intuition.

In philosophy, common Banoshie translations include "understanding" and "mind"; or sometimes "thought" or "reason" (in the sense of that which reasons, not the activity of reasoning). It is also often described as something equivalent to perception except that it works within the mind ("the mind's eye”). It has been suggested that the basic meaning is something like "awareness". In colloquial British English, nous also denotes "good sense", which is close to one everyday meaning it had in Ancient Greece.

Tis diagram shows the medieval understanding of spheres of the cosmos, derived from Aristotle, and as per the standard explanation by Ptolemy. It came to be understood that at least the outermost sphere (marked "Primũ Mobile") has its own intellect, intelligence or nous - a cosmic equivalent to the human mind.

In Aristotle's infuential works, the term was carefully distinguished from sense perception, imagination, and reason, although these terms are closely interrelated. Te term was apparently already singled out by earlier philosophers such as Parmenides, whose works are largely lost. In post-Aristotelian discussions, the exact boundaries between perception, understanding of perception, and reasoning have not always agreed with the defnitions of Aristotle, even though his terminology remains infuential.

In the Aristotelian scheme, nous is the basic understanding or awareness which allows human beings to think rationally. For Aristotle, this was distinct from the processing of sensory perception, including the use of imagination and memory, which other animals can do. Tis therefore connects discussion of nous, to discussion of how the human mind sets defnitions in a consistent and communicable way, and whether people must be born with some innate potential to understand the same universal categories the same logical ways. Deriving from this it was also sometimes argued, especially in classical and medieval philosophy, that the individual nous must require help of a spiritual and divine type. By this type of account, it came to be argued that the human understanding (nous) somehow stems from this cosmic nous, which is however not just a 138 recipient of order, but a creator of it. Such explanations were infuential in the development of medieval accounts of God, the immortality of the soul, and even the motions of the stars, in Europe, North Africa and the Middle East, amongst both eclectic philosophers and authors representing all the major faiths of their times.

Consciousness is the state or quality of awareness, or, of being aware of an external object or something within oneself. It has been defned variously in terms of sentience, awareness, qualia, subjectivity, the ability to experience or to feel, wakefulness, having a sense of selfhood or soul, the fact that there is something "that it is like" to "have" or "be" it, and the executive control system of the mind. In contemporary philosophy its defnition is often hinted at via the logical possibility of its absence, the philosophical zombie, which is defned as a being whose behavior and function are identical to one's own yet there is "no-one in there" experiencing it.

Despite the diﬃculty in defnition, many philosophers believe that there is a broadly shared underlying intuition about what consciousness is. As Max Velmans and Susan Schneider wrote in Te Blackwell Companion to Consciousness: "Anything that we are aware of at a given moment forms part of our consciousness, making conscious experience at once the most familiar and most mysterious aspect of our lives."

Western philosophers, since the time of Descartes and Locke, have struggled to comprehend the nature of consciousness and identify its essential properties. Issues of concern in the philosophy of consciousness include whether the concept is fundamentally coherent; whether consciousness can ever be explained mechanistically; whether non-human consciousness exists and if so how can it be recognized; how consciousness relates to language; whether consciousness can be understood in a way that does not require a dualistic distinction between mental and physical states or properties; and whether it may ever be possible for computing machines like computers or robots to be conscious, a topic studied in the feld of artifcial intelligence.

Tanks to developments in technology over the past few decades, consciousness has become a signifcant topic of interdisciplinary research in cognitive science, with signifcant contributions from felds such as psychology, anthropology, neuropsychology and neuroscience. Te primary focus is on understanding what it means biologically and psychologically for information to be present in consciousness—that is, on determining the neural and psychological correlates of consciousness. Te majority of experimental studies assess consciousness in humans by asking subjects for a verbal report of their experiences (e.g., "tell me if you notice anything when I do this"). Issues of interest include phenomena such as subliminal perception, blindsight, denial of impairment, and altered states of consciousness produced by alcohol and other drugs, or spiritual or meditative techniques.

In medicine, consciousness is assessed by observing a patient's arousal and responsiveness, and can be seen as a continuum of states ranging from full alertness and comprehension, through disorientation, delirium, loss of meaningful communication, and fnally loss of movement in response to painful stimuli. Issues of practical concern include how the presence of consciousness can be assessed in severely ill, comatose, or anesthetized people, and how to treat conditions in which consciousness is impaired or disrupted

Conscience is an aptitude, faculty, intuition or judgment that assists in distinguishing right from wrong. Moral judgment may derive from values or norms (principles and rules). In psychological terms conscience is often described as leading to feelings of remorse when a human commits actions that go against his/ her moral values and to feelings of rectitude or integrity when actions conform to such norms. Te extent to which conscience informs moral judgment before an action and whether such moral judgments are or should be based in reason has occasioned debate through much of the history of Western philosophy.

Religious views of conscience usually see it as linked to a morality inherent in all humans, to a benefcent universe and/or to divinity. Te diverse ritualistic, mythical, doctrinal, legal, institutional and material features of religion may not necessarily cohere with experiential, emotive, spiritual or contemplative considerations about the origin and operation of conscience. Common secular or scientifc views regard the capacity for conscience as probably genetically determined, with its subject probably learned or imprinted (like language) as part of a culture.

Commonly used metaphors for conscience include the "voice within", the "inner light",[5] or even Socrates' reliance on what the Greeks called his "daimōnic sign", an averting (ἀποτρεπτικός apotreptikos) inner voice heard only when he was about to make a mistake. Conscience, as is detailed in sections below, is a concept in national and international law, is increasingly conceived of as applying to the world as a whole, has motivated numerous notable acts for the public good and been the subject of many prominent examples of literature, music and flm.

139 Te secular approach to conscience includes psychological, physiological, sociological, humanitarian and authoritarian views. Lawrence Kohlberg considered critical conscience to be an important psychological stage in the proper moral development of humans, associated with the capacity to rationally weigh principles of responsibility, being best encouraged in the very young by linkage with humorous personifcations (such as Jiminy Cricket) and later in adolescents by debates about individually pertinent moral dilemmas. Erik Erikson placed the development of conscience in the 'pre-schooler' phase of his eight stages of normal human personality development. Te psychologist Martha Stout terms conscience "an intervening sense of obligation based in our emotional attachments." Tus a good conscience is associated with feelings of integrity, psychological wholeness and peacefulness and is often described using adjectives such as "quiet", "clear" and "easy".

Sigmund Freud regarded conscience as originating psychologically from the growth of civilisation, which periodically frustrated the external expression of aggression: this destructive impulse being forced to seek an alternative, healthy outlet, directed its energy as a superego against the person's own "ego" or selfshness (often taking its cue in this regard from parents during childhood).According to Freud, the consequence of not obeying our conscience is guilt, which can be a factor in the development of neurosis; Freud claimed that both the cultural and individual super-ego set up strict ideal demands with regard to the moral aspects of certain decisions, disobedience to which provokes a 'fear of conscience'.

Te word "conscience" derives etymologically from the Latin conscientia, meaning "privity of knowledge" or "with- knowledge". Te English word implies internal awareness of a moral standard in the mind concerning the quality of one's motives, as well as a consciousness of our own actions. Tus conscience considered philosophically may be frst, and perhaps most commonly, a largely unexamined "gut feeling" or "vague sense of guilt" about what ought to be or should have been done. Conscience in this sense is not necessarily the product of a process of rational consideration of the moral features of a situation (or the applicable normative principles, rules or laws) and can arise from parental, peer group, religious, state or corporate indoctrination, which may or may not be presently consciously acceptable to the person ("traditional conscience"). Conscience may be defned as the practical reason employed when applying moral convictions to a situation ("critical conscience"). In purportedly morally mature mystical people who have developed this capacity through daily contemplation or meditation combined with selfess service to others, critical conscience can be aided by a "spark" of intuitive insight or revelation (called marifa in Islamic Suf philosophy and synderesis in medieval Christian scholastic moral philosophy). Conscience is accompanied in each case by an internal awareness of 'inner light' and approbation or 'inner darkness' and condemnation as well as a resulting conviction of right or duty either followed or declined.

Reality is the state of things as they actually exist, as opposed to an idealistic or notional idea of them. Reality includes everything that is and has been, whether or not it is observable or comprehensible. A still broader defnition includes that which has existed, exists, or will exist.

Philosophers, mathematicians, and other ancient and modern thinkers, such as Aristotle, Plato, Frege, Wittgenstein, and Russell, have made a distinction between thought corresponding to reality, coherent abstractions (thoughts of things that are imaginable but not real), and that which cannot even be rationally thought. By contrast, existence is often restricted solely to that which has physical existence or has a direct basis in it in the way that thoughts do in the brain.

Reality is often contrasted with what is imaginary, illusory, delusional, (only) in the mind, dreams, what is false, what is fctional, or what is abstract. At the same time, what is abstract plays a role both in everyday life and in academic research. For instance, causality, virtue, life, and distributive justice are abstract concepts that can be diﬃcult to defne, but they are only rarely equated with pure delusions. Both the existence and reality of abstractions are in dispute: one extreme position regards them as mere words; another position regards them as higher truths than less abstract concepts. Tis disagreement is the basis of the philosophical problem of universals.

An illusion is a distortion of the senses, revealing how the human brain normally organizes and interprets sensory stimulation. Tough illusions distort reality, they are generally shared by most people.

Illusions may occur with any of the human senses, but visual illusions (optical illusions) are the best-known and understood. Te emphasis on visual illusions occurs because vision often dominates the other senses. For example, individuals watching a ventriloquist will perceive the voice is coming from the dummy since they are able to see the dummy mouth the words.

Some illusions are based on general assumptions the brain makes during perception. Tese assumptions are made using organizational principles (e.g., Gestalt theory), an individual's capacity for depth perception and motion perception, and perceptual constancy. Other illusions occur because of biological sensory structures within the human body or conditions outside the body within one's physical environment.

Te term illusion refers to a specifc form of sensory distortion. Unlike a hallucination, which is a distortion in the absence of a stimulus, an illusion describes a misinterpretation of a true sensation. For example, hearing voices regardless of the

140 environment would be a hallucination, whereas hearing voices in the sound of running water (or other auditory source) would be an illusion.

Te Individual is god’s concept that we are all totally unique and separate from everything else except him if so deemed by our will and understanding. Individualism is also the moral stance, political philosophy, ideology, or social outlook that emphasizes the moral worth of the individual. Individualists promote the exercise of one's goals and desires and so value independence and self-reliance and advocate that interests of the individual should achieve precedence over the state or a social group, while opposing external interference upon one's own interests by society or institutions such as the government. Individualism is often defned in contrast to totalitarianism, collectivism, authoritarianism, communitarianism, statism, tribalism, and more corporate social forms.

Individualism makes the individual its focus and so starts "with the fundamental premise that the human individual is of primary importance in the struggle for liberation." Classical liberalism, existentialism, and anarchism are examples of movements that take the human individual as a central unit of analysis. Individualism thus involves "the right of the individual to freedom and self-realization".

It has also been used as a term denoting "Te quality of being an individual; individuality" related to possessing "An individual characteristic; a quirk." Individualism is thus also associated with artistic and bohemian interests and lifestyles where there is a tendency towards self-creation and experimentation as opposed to tradition or popular mass opinions and behaviors as so also with humanist philosophical positions and ethics.

Subjectivity is a central philosophical concept, related to consciousness, agency, personhood, reality, and truth, which has been variously defned by sources. Tree common defnitions include that subjectivity is the quality or condition of:

Something being a subject, narrowly meaning an individual who possesses conscious experiences, such as perspectives, feelings, beliefs, and desires. Something being a subject, broadly meaning an entity that has agency, meaning that it acts upon or wields power over some other entity (an object). Some information, idea, situation, or physical thing considered true only from the perspective of a subject or subjects Tese various defnitions of subjectivity are sometimes joined together in philosophy. Te term is most commonly used as an explanation for that which infuences, informs, and biases people's judgments about truth or reality; it is the collection of the perceptions, experiences, expectations, personal or cultural understanding, and beliefs specifc to a person.

Subjectivity is contrasted to the philosophy of objectivity, which is described as a view of truth or reality that is free of any individual's biases, interpretations, feelings, and imaginings.

A subject is a being who has a unique consciousness and/or unique personal experiences, or an entity that has a relationship with another entity that exists outside itself (called an "object"). A subject is an observer and an object is a thing observed. Tis concept is especially important in Continental philosophy, where 'the Subject' is a central term in debates over human autonomy and the nature of the self.

Te sharp distinction between subject and object corresponds to the distinction, in the philosophy of René Descartes, between thought and extension. Descartes believed that thought (subjectivity) was the essence of the mind, and that extension (the occupation of space) was the essence of matter.

In the modern continental tradition, debates over the nature of the Subject play a role comparable to debates over personhood within the distinct Anglo- American tradition of analytical philosophy.

In critical theory and psychology, subjectivity is also the actions or discourses that produce individuals or 'I'—the 'I' is the subject.

Objectivity is a central philosophical concept, related to reality and truth, which has been variously defned by sources. Generally, objectivity means the state or quality of being true even outside a subject's individual biases, interpretations, feelings, and imaginings. A proposition is generally considered objectively true (to have objective truth) when its truth conditions are met without biases caused by feelings, ideas, opinions, etc., of a sentient subject. A second, broader meaning of the term refers to the ability in any context to judge fairly, without partiality or external infuence. Tis second meaning of objectivity is sometimes used synonymously with neutrality.

An object is a technical term in modern philosophy often used in contrast to the term subject. A subject is an observer and an object is a thing observed. For modern philosophers like Descartes, consciousness is a state of cognition that includes the subject—which can never be doubted as only it can be the one who doubts–—and some object(s) that may be considered as

141 not having real or full existence or value independent of the subject who observes it. Metaphysical frameworks also diﬀer in whether they consider objects exist independently of their properties and, if so, in what way.

Te pragmatist Charles S. Peirce defnes the broad notion of an object as anything that we can think or talk about. In a general sense it is any entity: the pyramids, Alpha Centauri, the number seven, a disbelief in predestination or the fear of cats. In a strict sense it refers to any defnite being.

A related notion is objecthood. Objecthood is the state of being an object. One approach to defning it is in terms of objects' properties and relations. Descriptions of all bodies, minds, and persons must be in terms of their properties and relations. Te philosophical question of the nature of objecthood concerns how objects are related to their properties and relations. For example, it seems that the only way to describe an apple is by describing its properties and how it is related to other things. Its properties may include its redness, its size, and its composition, while its relations may include "on the table", "in the room" and "being bigger than other apples".

Te notion of an object must address two problems: the change problems and the problems of substances. Two leading theories about objecthood are substance theory, wherein substances (objects) are distinct from their properties, and bundle theory, wherein objects are no more than bundles of their properties.

Substance theory, or substance–attribute theory, is an ontological theory about objecthood positing that a substance is distinct from its properties. A thing-in-itself is a property-bearer that must be distinguished from the properties it bears. [1] Te corresponding concept in Eastern philosophy is svabhava. Substance is a key concept in ontology and metaphysics, which may be classifed into monist, dualist, or pluralist varieties according to how many substances or individuals are said to populate, furnish, or exist in the world. According to monistic views, there is only one substance. Stoicism and Spinoza, for example, hold monistic views, that pneuma or God, respectively, is the one substance in the world. Tese modes of thinking are sometimes associated with the idea of immanence. Dualism sees the world as being composed of two fundamental substances (for example, the Cartesian substance dualism of mind and matter). Pluralist philosophies include Plato's Teory of Forms and Aristotle's hylomorphic categories.

Aristotle used the term "substance" (Greek: οὐσία ousia) in a secondary sense for genera and species understood as hylomorphic forms. Primarily, however, he used it with regard to his category of substance, the specimen ("this person" or "this horse") or individual, qua individual, who survives accidental change and in whom the essential properties inhere that defne those universals. A substance—that which is called a substance most strictly, primarily, and most of all—is that which is neither said of a subject nor in a subject, e.g. the individual man or the individual horse. Te species in which the things primarily called substances are, are called secondary substances, as also are the genera of these species. For example, the individual man belongs in a species, man, and animal is a genus of the species; so these—both man and animal—are called secondary substances.[2] In chapter 6 of book I the Physics Aristotle argues that any change must be analysed in reference to the property of an invariant subject: as it was before the change and thereafter. Tus, in his hylomorphic account of change, matter serves as a relative substratum of transformation, i.e., of changing (substantial) form. In the Categories, properties are predicated only of substance, but in chapter 7 of book I of the Physics, Aristotle discusses substances coming to be and passing away in the "unqualifed sense" wherein primary substances (πρῶται οὐσίαι; Categories 2a35) are generated from (or perish into) a material substratum by having gained (or lost) the essential property that formally defnes substances of that kind (in the secondary sense). Examples of such a substantial change include not only conception and dying, but also metabolism, e.g., the bread a man eats becomes the man. On the other hand, in accidental change, because the essential property remains unchanged, by identifying the substance with its formal essence, substance may thereby serve as the relative subject matter or property-bearer of change in a qualifed sense (i.e., barring matters of life or death). An example of this sort of accidental change is a change of color or size: a tomato becomes red, or a juvenile horse grows.

Aristotle thinks that in addition to primary substances (which are particulars), there are secondary substances (δεύτεραι οὐσίαι), which are universals (Categories 2a11–a18).[3] Neither the "bare particulars" nor "property bundles" of modern theory have their antecedent in Aristotle, according to whom all matter exists in some form. Tere is no prime matter or pure elements, there is always a mixture: a ratio weighing the four potential combinations of primary and secondary properties and analysed into discrete one-step and two-step abstract transmutations between the elements.[citation needed]

142 However, according to Aristotle's theology, a form of invariant form exists without matter, beyond the cosmos, powerless and oblivious, in the eternal substance of the unmoved movers. In his frst philosophy, later called the Metaphysics, (or “after the Physics”), Aristotle discusses the meaning of being. He refers to the unmoved movers (hyperagents), and assigns one to each movement in the heavens and tasks future astronomers with correlating the estimated 47 to 55 motions of the Eudoxan planetary model with the most current and accurate observations. According to Aristotle, each unmoved mover continuously contemplates its own contemplation; the planets and stars, which have their source of motion within themselves (by virtue of aether, Aristotle's ffth element) aspire to emulate the uniform circular motion of their particular mover. Tus captivated, their tireless performance is entirely the result of their own desire. Tis is one way in which the movers are said to be unmoved. Likewise, they must have no sensory perception whatsoever on account of Aristotle's theory of cognition: were any form of sense perception to intrude upon their thoughts, in that instant they would cease to be themselves, because actual self-refection is their singular essence, their whole being. Like the heavenly bodies in their unadorned pursuit, so the wise look, with aﬀection, toward the star; and hence as a role model, they inspire those who look up to them, and by whom others still, will yet fnd themselves enthralled, and so on, creating the enduring natural order of aeon, season, animal and plant.

In the Metaphysics, Aristotle discusses actuality (entelecheia, Greek: ἐντελέχεια) and potentiality (dynamis, Greek: δύναμις). Te former is perfection, realization, fullness of being; the latter imperfection, incompleteness, perfectibility. Te former is the determining, the latter the determinable principle. Te unmoved movers are entirely actual, Actus Purus, because they are unchanging, eternal, immaterial substance. All material beings have some potentiality. Te Physics introduces matter and form and the four causes—material, formal, eﬃcient and fnal. For example, to explain a statue, one can oﬀer:

• Te material cause, that out of which the statue is made, is the marble or bronze. • Te formal cause, that according to which the statue is made, is the shape that the sculptor has learned to sculpt. • Te eﬃcient cause, or agent, is the sculptor. • Te fnal cause, is that for the sake of which the statue is made, the (actual) statue. Contrary to the later so-called "traditional" view of prime matter (prima materia in Latin), Aristotle asserts that there can be no pure potentiality without any actuality whatsoever. All material substances have unactualized potentials. Aristotle argues that, although motion is eternal, there cannot be an infnite series of movers and of things moved. Terefore, there must be some, who are not the frst in such a series, that inspire the eternal motion without themselves being moved "as the soul is moved by beauty". Because the planetary spheres each move unfalteringly for all eternity in uniform circular motion with a given rotational period relative to the supreme diurnal motion of the sphere of fxed stars (or First Heaven), they must each love and desire to mimic diﬀerent unmoved movers corresponding to the given periods. Because they eternally inspire uniform motion in the celestial spheres, the unmoved movers must themselves be eternal and unchanging. Because they are eternal, they have already had an infnite amount of time in which to actualize any potentialities and therefore cannot be a composition of matter and form, or potentiality and actuality. Tey must always be fully actual, and thus immaterial, because at all times in history they have already existed an infnite amount of time, and things that do not actually come to fruition given unlimited opportunities to do so cannot potentially do so.

Te life of the unmoved mover is self-contemplative thought ("νοήσεως νόησις (noeseos noesis)", i.e. "thought of thought").[1][2] According to Aristotle, the gods cannot potentially be distracted from this eternal self-contemplation because, in that instant, they would cease to exist.

Te truth refers to what is real, while falsity refers to what is not. Fictions are considered not real.

Epistemology (/ɪˌpɪstɪˈmɒlədʒi/ (About this sound listen); from Greek ἐπιστήμη, epistēmē, meaning 'knowledge', and λόγος, logos, meaning 'logical discourse') is the branch of philosophy concerned with the theory of knowledge.

Epistemology studies the nature of knowledge, justifcation, and the rationality of belief. Much of the debate in epistemology centers on four areas: the philosophical analysis of the nature of knowledge and how it relates to such concepts as truth, belief, and justifcation, various problems of skepticism, the sources and scope of knowledge and justifed belief, and the criteria for knowledge and justifcation. Epistemology addresses such questions as "What makes justifed beliefs justifed?", "What does it mean to say that we know something?" and fundamentally "How do we know that we know?"

143 Te term 'Epistemology' was frst used by Scottish philosopher James Frederick Ferrier in 1854.[a] However, according to Brett Warren, King James VI of Scotland had previously personifed this philosophical concept as the character Epistemon in 1591.

Intelligence has been defned in many diﬀerent ways including as one's capacity for logic, understanding, self-awareness, learning, emotional knowledge, planning, creativity, and problem solving. It can be more generally described as the ability or inclination to perceive or deduce information, and to retain it as knowledge to be applied towards adaptive behaviors within an environment or context.

Intelligence is most widely studied in humans, but has also been observed in non-human animals and in plants. Artifcial intelligence is intelligence in machines. It is commonly implemented in computer systems using program software.

Within the discipline of psychology, various approaches to human intelligence have been adopted. Te psychometric approach is especially familiar to the general public, as well as being the most researched and by far the most widely used in practical settings.

In mathematics, it is known that 2 + 2 = 4, but there is also knowing how to add two numbers, and knowing a person (e.g., oneself), place (e.g., one's hometown), thing (e.g., cars), or activity (e.g., addition). Some philosophers think there is an important distinction between "knowing that" (know a concept), "knowing how" (understand an operation), and "acquaintance-knowledge" (know by relation), with epistemology being primarily concerned with the frst of these.

While these distinctions are not explicit in Banoshie, they are defned explicitly in other languages (N.B. some languages related to English have been said to retain these verbs, e.g. Scots: "wit" and "ken"). In French, Portuguese, Spanish, German and Dutch to know (a person) is translated using connaître, conhecer, conocer and kennen respectively, whereas to know (how to do something) is translated using savoir, saber, wissen and weten. Modern Greek has the verbs γνωρίζω (gnorízo) and ξέρω (kséro). Italian has the verbs conoscere and sapere and the nouns for knowledge are conoscenza and sapienza. German has the verbs wissen and kennen. Wissen implies knowing a fact, kennen implies knowing in the sense of being acquainted with and having a working knowledge of; there is also a noun derived from kennen, namely Erkennen, which has been said to imply knowledge in the form of recognition or acknowledgment. Te verb itself implies a process: you have to go from one state to another, from a state of "not-erkennen" to a state of true erkennen. Tis verb seems to be the most appropriate in terms of describing the "episteme" in one of the modern European languages, hence the German name "Erkenntnistheorie". Te theoretical interpretation and signifcance of these linguistic issues remains controversial.

In his paper On Denoting and his later book Problems of Philosophy Bertrand Russell stressed the distinction between "knowledge by description" and "knowledge by acquaintance". Gilbert Ryle is also credited with stressing the distinction between knowing how and knowing that in Te Concept of Mind. In

Personal Knowledge, Michael Polanyi argues for the epistemological relevance of knowledge how and knowledge that; using the example of the act of balance involved in riding a bicycle, he suggests that the theoretical knowledge of the physics involved in maintaining a state of balance cannot substitute for the practical knowledge of how to ride, and that it is important to understand how both are established and grounded. Tis position is essentially Ryle's, who argued that a failure to acknowledge the distinction between knowledge that and knowledge how leads to infnite regress.

In recent times, epistemologists including Sosa, Greco, Kvanvig, Zagzebski and Duncan Pritchard have argued that epistemology should evaluate people's "properties" (i.e., intellectual virtues) and not just the properties of propositions or of propositional mental attitudes.[citation needed]

Belief: In common speech, a "statement of belief" is typically an expression of faith or trust in a person, power or other entity—while it includes such traditional views, epistemology is also concerned with what we believe. Tis includes 'the' truth, and everything else we accept as 'true' for ourselves from a cognitive point of view.

Whether someone's belief is true is not a prerequisite for (its) belief. On the other hand, if something is actually known, then it categorically cannot be false. For example, if a person believes that a bridge is safe enough to support him, and attempts to cross it, but the bridge then collapses under his weight, it could be said that he believed that the bridge was safe but that his belief was mistaken. It would not be accurate to say that he knew that the bridge was safe, because plainly it was not. By contrast, if the bridge actually supported his weight, then he might say that he had believed that the bridge was safe, whereas now, after proving it to himself (by crossing it), he knows it was safe.

144 Epistemologists argue over whether belief is the proper truth-bearer. Some would rather describe knowledge as a system of justifed true propositions, and others as a system of justifed true sentences. Plato, in his Gorgias, argues that belief is the most commonly invoked truth-bearer.

Justifcation: In the Teaetetus, Socrates considers a number of theories as to what knowledge is, the last being that knowledge is true belief "with an account" (meaning explained or defned in some way). According to the theory that knowledge is justifed true belief, in order to know that a given proposition is true, one must not only believe the relevant true proposition, but one must also have a good reason for doing so. One implication of this would be that no one would gain knowledge just by believing something that happened to be true. For example, an ill person with no medical training, but with a generally optimistic attitude, might believe that he will recover from his illness quickly. Nevertheless, even if this belief turned out to be true, the patient would not have known that he would get well since his belief lacked justifcation.

Te defnition of knowledge as justifed true belief was widely accepted until the 1960s. At this time, a paper written by the American philosopher Edmund Gettier provoked major widespread discussion. (See theories of justifcation for other views on the idea.)

Gettier problem Euler diagram representing a defnition of knowledge. Edmund Gettier is best known for a short paper entitled 'Is Justifed True Belief Knowledge?' published in 1963, which called into question the theory of knowledge that had been dominant among philosophers for thousands of years. Tis in turn called into question the actual value of philosophy if such an obvious and easy counterexample to a major theory could exist without anyone noticing it for thousands of years. In a few pages, Gettier argued that there are situations in which one's belief may be justifed and true, yet fail to count as knowledge. Tat is, Gettier contended that while justifed belief in a true proposition is necessary for that proposition to be known, it is not suﬃcient. As in the diagram, a true proposition can be believed by an individual (purple region) but still not fall within the "knowledge" category (yellow region).

According to Gettier, there are certain circumstances in which one does not have knowledge, even when all of the above conditions are met. Gettier proposed two thought experiments, which have come to be known as "Gutter cases", as counterexamples to the classical account of knowledge. One of the cases involves two men, Smith and Jones, who are awaiting the results of their applications for the same job. Each man has ten coins in his pocket. Smith has excellent reasons to believe that Jones will get the job and, furthermore, knows that Jones has ten coins in his pocket (he recently counted them). From this Smith infers, "the man who will get the job has ten coins in his pocket." However, Smith is unaware that he also has ten coins in his own pocket. Furthermore, Smith, not Jones, is going to get the job. While Smith has strong evidence to believe that Jones will get the job, he is wrong. Smith has a justifed true belief that the man who will get the job has ten coins in his pocket; however, according to Gettier, Smith does not know that the man who will get the job has ten coins in his pocket, because Smith's belief is "...true by virtue of the number of coins in Jones's pocket, while Smith does not know how many coins are in Smith's pocket, and bases his belief...on a count of the coins in Jones's pocket, whom he falsely believes to be the man who will get the job." Tese cases fail to be knowledge because the subject's belief is justifed, but only happens to be true by virtue of luck. In other words, he made the correct choice (in this case predicting an outcome) for the wrong reasons. Tis example is similar to those often given when discussing belief and truth, wherein a person's belief of what will happen can coincidentally be correct without his or her having the actual knowledge to base it on.

Wisdom or sapience is the ability to think and act using knowledge, experience, understanding, common sense, and insight. Tere appears to be consensus that wisdom is associated with attributes such as compassion, experiential self-knowledge, non-attachment and virtues such as ethics and benevolence.

Wisdom has been defned in many diﬀerent ways, a variety of measurement scales have been developed, and several subtypes of wisdom have been proposed. Out of these, phronesis and sophia are two key subtypes of wisdom. In the classical Greek tradition, there is a distinction between sophia "wisdom" and phronesis "prudence, practical intelligence”.

Sapience is closely related to the term "sophia" often defned as "transcendent wisdom", "ultimate reality", or the ultimate truth of things. Sapiential perspective of wisdom is said to lie in the heart of every religion, where it is often acquired through intuitive knowing. Tis type of wisdom is described as going beyond mere practical wisdom and includes self- knowledge, interconnectedness, conditioned origination of mind-states and other deeper understandings of subjective experience. Tis type of wisdom can also lead to the ability of an individual to act with appropriate judgement, a broad understanding of situations and greater appreciation/compassion towards other living beings.

Te word sapience is derived from the Latin sapientia, meaning "wisdom". Te corresponding verb sapere has the original meaning of "to taste", hence "to perceive, to discern" and "to know"; its present participle sapiens was chosen by Carl Linnaeus for the Latin binomial for the human species, Homo sapiens.

145 Sentience is the capacity to feel, perceive or experience subjectively. Eighteenth-century philosophers used the concept to distinguish the ability to think (reason) from the ability to feel (sentience). In modern Western philosophy, sentience is the ability to experience sensations (known in philosophy of mind as "qualia"). In Eastern philosophy, sentience is a metaphysical quality of all things that require respect and care. Te concept is central to the philosophy of animal rights because sentience is necessary for the ability to suﬀer, and thus is held to confer certain rights.

A phenomenon (Greek: φαινόμενον, phainómenon, from the verb phainein, to show, shine, appear, to be manifest or manifest itself, plural phenomena) is any thing which manifests itself. Phenomena are often, but not always, understood as "things that appear" or "experiences" for a sentient being, or in principle may be so.

Te term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon. In contrast to a phenomenon, a noumenon can not be directly observed. Kant was heavily infuenced by Gottfried Wilhelm Leibniz in this part of his philosophy, in which phenomenon and noumenon serve as interrelated technical terms. Far predating this, the ancient Greek Pyrrhonist philosopher Sextus Empiricus also used phenomenon and noumenon as interrelated technical terms.

In metaphysics, the noumenon (/ˈnuːmənɒn/, also UK: /ˈnaʊmənɒn/, from Greek: [εν]νοούμενον) is a posited object or event that exists independently of human sense and/or perception. Te term noumenon is generally used when contrasted with, or in relation to, the term phenomenon, which refers to anything that can be apprehended by or is an object of the senses. Modern philosophy has generally been skeptical of the possibility of knowledge independent of the senses, and Immanuel Kant gave this point of view its canonical expression: that the noumenal world may exist, but it is completely unknowable through human sensation. In Kantian philosophy, the unknowable noumenon is often linked to the unknowable "thing-in-itself " (in Kant's German, Ding an sich), although how to characterize the nature of the relationship is a question yet open to some controversy.

In philosophy, mathematics, and logic, a property is a characteristic of an object; a red object is said to have the property of redness. Te property may be considered a form of object in its own right, able to possess other properties. A property however differs from individual objects in that it may be instantiated, and often in more than one thing. It differs from the logical/mathematical concept of class by not having any concept of extensionality, and from the philosophical concept of class in that a property is considered to be distinct from the objects which possess it. Understanding how different individual entities (or particulars) can in some sense have some of the same properties is the basis of the problem of universals. Te terms attribute and quality have similar meanings.

In philosophy, a quality is an attribute or a property characteristic of an object. In contemporary philosophy the idea of qualities, and especially how to distinguish certain kinds of qualities from one another, remains controversial.

In philosophy, ideas are usually construed as mental representational images of some object. Ideas can also be abstract concepts that do not present as mental images. Many philosophers have considered ideas to be a fundamental ontological category of being. Te capacity to create and understand the meaning of ideas is considered to be an essential and defning feature of human beings. In a popular sense, an idea arises in a refexive, spontaneous manner, even without thinking or serious refection, for example, when we talk about the idea of a person or a place. A new or original idea can often lead to innovation.

Innovation can be defned simply as a "new idea, device or method". However, innovation is often also viewed as the application of better solutions that meet new requirements, unarticulated needs, or existing market needs.Tis is accomplished through more-eﬀective products, processes, services, technologies, or business models that are readily available to markets, governments and society. Te term "innovation" can be defned as something original and more eﬀective and, as a consequence, new, that "breaks into" the market or society. It is related to, but not the same as, invention, as innovation is more apt to involve the practical implementation of an invention (i.e. new/improved ability) to make a meaningful impact in the market or society, and not all innovations require an invention. Innovation is often manifested via the engineering process, when the problem being solved is of a technical or scientifc nature. Te opposite of innovation is exnovation.

While a novel device is often described as an innovation, in economics, management science, and other felds of practice and analysis, innovation is generally considered to be the result of a process that brings together various novel ideas in a way that they aﬀect society. In industrial economics, innovations are created and found empirically from services to meet the growing consumer demand.

Eternity in common parlance is either an infnite or an indeterminately long period of time. In classical philosophy, however, eternity is defned as what exists outside time while sempiternity is the concept that corresponds to the colloquial defnition of eternity. 146 Eternity is an important concept in many religions, where the god or gods are said to endure eternally. Some, such as Aristotle, would say the same about the natural cosmos in regard to both past and future eternal duration, and like the eternal Platonic forms, immutability was considered essential.

Ethics or moral philosophy is a branch of philosophy that involves systematizing, defending, and recommending concepts of right and wrong conduct. Te term ethics derives from Ancient Greek ἠθικός (ethikos), from ἦθος (ethos), meaning 'habit, custom'. Te branch of philosophy axiology comprises the sub- branches of ethics and aesthetics, each concerned with values.

Ethics seeks to resolve questions of human morality by defning concepts such as good and evil, right and wrong, virtue and vice, justice and crime. As a feld of intellectual enquiry, moral philosophy also is related to the felds of moral psychology, descriptive ethics, and value theory.

Tree major areas of study within ethics recognized today are:

Meta-ethics, concerning the theoretical meaning and reference of moral propositions, and how their truth values (if any) can be determined Normative ethics, concerning the practical means of determining a moral course of action Applied ethics, concerning what a person is obligated (or permitted) to do in a specifc situation or a particular domain of action.

Meta-ethics is the branch of ethics that seeks to understand the nature of ethical properties, statements, attitudes, and judgments. Meta-ethics is one of the three branches of ethics generally studied by philosophers, the others being normative ethics and applied ethics.

While normative ethics addresses such questions as "What should I do?", thus endorsing some ethical evaluations and rejecting others, meta-ethics addresses questions such as "What is goodness?" and "How can we tell what is good from what is bad?", seeking to understand the nature of ethical properties and evaluations.

Some theorists argue that a metaphysical account of morality is necessary for the proper evaluation of actual moral theories and for making practical moral decisions; others reason from opposite premises and suggest that we must impart ideas of moral intuition onto proper action before we can give a proper account of morality's metaphysics.

Normative ethics is the study of ethical action. It is the branch of philosophical ethics that investigates the set of questions that arise when considering how one ought to act, morally speaking. Normative ethics is distinct from meta-ethics because it examines standards for the rightness and wrongness of actions, while meta-ethics studies the meaning of moral language and the metaphysics of moral facts. Normative ethics is also distinct from descriptive ethics, as the latter is an empirical investigation of people’s moral beliefs. To put it another way, descriptive ethics would be concerned with determining what proportion of people believe that killing is always wrong, while normative ethics is concerned with whether it is correct to hold such a belief. Hence, normative ethics is sometimes called prescriptive, rather than descriptive. However, on certain versions of the meta-ethical view called moral realism, moral facts are both descriptive and prescriptive at the same time.

Most traditional moral theories rest on principles that determine whether an action is right or wrong. Classical theories in this vein include utilitarianism, Kantianism, and some forms of contractarianism. Tese theories mainly oﬀered the use of overarching moral principles to resolve diﬃcult moral decisions.

Applied ethics is the branch of ethics concerned with the analysis of particular moral issues in private and public life. For example, the bioethics community is concerned with identifying the correct approach to moral issues in the life sciences, such as euthanasia, the allocation of scarce health resources, or the use of human embryos in research. Environmental ethics is concerned with ecological issues such as the responsibility of government and corporations to clean up pollution. Business ethics includes questions regarding the duties or duty of 'whistleblowers' to the general public or to their loyalty to their employers. Applied ethics is distinguished from normative ethics, which concerns standards for right and wrong behavior, and from meta-ethics, which concerns the nature of ethical properties, statements, attitudes, and judgments.

Morality (from the Latin moralis "manner, character, proper behavior") is the diﬀerentiation of intentions, decisions and actions between those that are distinguished as proper and those that are improper. Morality can be a body of standards or principles derived from a code of conduct from a particular philosophy, religion or culture, or it can derive from a standard that a person believes should be universal. Morality may also be specifcally synonymous with "goodness" or "rightness".

147 Moral philosophy includes moral ontology, which is the origin of morals and moral epistemology, which is the knowledge of morals. Diﬀerent systems of expressing morality have been proposed, including deontological ethical systems which adhere to a set of established rules, and normative ethical systems which consider the merits of actions themselves. An example of normative ethical philosophy is the Golden Rule, which states that: "One should treat others as one would like others to treat oneself."

Immorality is the active opposition to morality (i.e. opposition to that which is good or right), while amorality is variously defned as an unawareness of, indiﬀerence toward, or disbelief in any particular set of moral standards or principles

Teosophy is a collection of mystical and occultist philosophies concerning, or seeking direct knowledge of the presumed mysteries of life and nature, particularly of the nature of divinity and the origin and purpose of the universe. Teosophy is considered part of Western esotericism, which believes that hidden knowledge or wisdom from the ancient past oﬀers a path to enlightenment and salvation.

Mysticism is popularly known as becoming one with God or the Absolute, but may refer to any kind of ecstasy or altered state of consciousness which is given a religious or spiritual meaning. It may also refer to the attainment of insight in ultimate or hidden truths, and to human transformation supported by various practices and experiences.

Te term "mysticism" has Ancient Greek origins with various historically determined meanings. Derived from the Greek word μυω, meaning "to conceal”, mysticism referred to the biblical liturgical, spiritual, and contemplative dimensions of early and medieval Christianity. During the early modern period, the defnition of mysticism grew to include a broad range of beliefs and ideologies related to "extraordinary experiences and states of mind".

In modern times, "mysticism" has acquired a limited defnition, with broad applications, as meaning the aim at the "union with the Absolute, the Infnite, or God”. Tis limited defnition has been applied to a wide range of religious traditions and practices, valuing "mystical experience" as a key element of mysticism.

Broadly defned, mysticism can be found in all religious traditions, from indigenous religions and folk religions like shamanism, to organised religions like the Abrahamic faiths and Indian religions, and modern spirituality, New Age and New Religious Movements.

Since the 1960s scholars have debated the merits of perennial and constructionist approaches in the scientifc research of "mystical experiences". Te perennial position is now "largely dismissed by scholars", most scholars using a contextual approach, which takes the cultural and historical context into consideration.

Te occult (from the Latin word occultus "clandestine, hidden, secret") is "knowledge of the hidden". In common English usage, occult refers to "knowledge of the paranormal", as opposed to "knowledge of the measurable", usually referred to as science. Te term is sometimes taken to mean knowledge that "is meant only for certain people" or that "must be kept hidden", but for most practicing occultists it is simply the study of a deeper spiritual reality that extends beyond pure reason and the physical sciences. Te terms esoteric and arcane can also be used to describe the occult, in addition to their meanings unrelated to the supernatural.

It also describes a number of magical organizations or orders, the teachings and practices taught by them, and to a large body of current and historical literature and spiritual philosophy related to this subject. esotericism (also called esotericism and esoterism), also known as the Western mystery tradition, is a scholarly term for a wide range of loosely related ideas and movements which have developed within Western society. Tey are largely distinct both from orthodox Judeo-Christian religion and from Enlightenment rationalism. A trans-disciplinary feld, esotericism has pervaded various forms of Western philosophy, religion, pseudoscience, art, literature, and music, continuing to aﬀect intellectual ideas and popular culture.

Te idea of categorising a wide range of Western traditions and philosophies together under the rubric that we now term "esotericism" developed in Europe during the late seventeenth century. Various academics have debated the precise defnition of Western esotericism, with a number of diﬀerent options proposed. One scholarly model adopts its defnition of "esotericism" from certain esotericist schools of thought themselves, treating "esotericism" as a perennialist hidden, inner tradition. A second perspective sees esotericism as a category that encompasses world-views which seek to embrace an "enchanted" world-view in the face of increasing de-enchantment. A third views Western esotericism as a category encompassing all of Western culture's "rejected knowledge" that is accepted neither by the scientifc establishment nor by orthodox religious authorities.

148 Te earliest traditions which later analysis would label as forms of Western esotericism emerged in the Eastern Mediterranean during Late Antiquity, where Hermetism, Gnosticism, and Neoplatonism developed as schools of thought distinct from what became mainstream Christianity. In Renaissance Europe, interest in many of these older ideas increased, with various intellectuals seeking to combine "pagan" philosophies with the Kabbalah and with Christian philosophy, resulting in the emergence of esoteric movements like Christian theosophy. Te 17th century saw the development of initiatory societies professing esoteric knowledge such as Rosicrucianism and Freemasonry, while the Age of Enlightenment of the 18th century led to the development of new forms of esoteric thought. Te 19th century saw the emergence of new trends of esoteric thought that have come to be known as occultism. Prominent groups in this century included the Teosophical Society and the Hermetic Order of the Golden Dawn, which infuenced the development of Telema. Modern Paganism developed within occultism, and includes religious movements such as Wicca. Esoteric ideas permeated the counterculture of the 1960s and later cultural tendencies, from which emerged the New Age movement in the 1970s.

Although the idea that these varying movements could be categorised together under the rubric of "Western esotericism" developed in the late 18th century, these esoteric currents were largely ignored as a subject of academic enquiry. Te academic study of Western esotericism only emerged in the late 20th-century, pioneered by scholars like Frances Yates (1899-1981) and Antoine Faivre (born 1934). Esoteric ideas have meanwhile also exerted an infuence in popular culture, appearing in art, literature, flm, and music.

Certainty is perfect knowledge that has total security from error, or the mental state of being without doubt.

Objectively defned, certainty is total continuity and validity of all foundational inquiry, to the highest degree of precision. Something is certain only if no skepticism can occur. Philosophy (at least, historical Cartesian philosophy) seeks this state.

Determinism is the philosophical theory that all events, including moral choices, are completely determined by previously existing causes. Determinism is usually understood to preclude free will because it entails that humans cannot act otherwise than they do. Te theory holds that the universe is utterly rational because complete knowledge of any given situation assures that unerring knowledge of its future is also possible. Some philosophers suggest variants around this basic defnition. Deterministic theories throughout the history of philosophy have sprung from diverse and sometimes overlapping motives and considerations. Te opposite of determinism is some kind of indeterminism (otherwise called nondeterminism). Determinism is often contrasted with free will.

Determinism often is taken to mean causal determinism, which in physics is known as cause-and-eﬀect. It is the concept that events within a given paradigm are bound by causality in such a way that any state (of an object or event) is completely determined by prior states. Tis meaning can be distinguished from other varieties of determinism mentioned below.

Other debates often concern the scope of determined systems, with some maintaining that the entire universe is a single determinate system and others identifying other more limited determinate systems (or multiverse). Numerous historical debates involve many philosophical positions and varieties of determinism. Tey include debates concerning determinism and free will, technically denoted as compatibilistic (allowing the two to coexist) and incompatibilistic (denying their coexistence is a possibility).

Determinism should not be confused with self-determination of human actions by reasons, motives, and desires. Determinism rarely requires that perfect prediction be practically possible.

Fatalism is a philosophical doctrine that stresses the subjugation of all events or actions to destiny. Fatalism generally refers to any of the following ideas:

Te view that we are powerless to do anything other than what we actually do. Included in this is that humans have no power to infuence the future, or indeed, their own actions. Tis belief is very similar to predeterminism. An attitude of resignation in the face of some future event or events which are thought to be inevitable. Friedrich Nietzsche named this idea "Turkish fatalism" in his book Te Wanderer and His Shadow.

Tat acceptance is appropriate, rather than resistance against inevitability. Tis belief is very similar to defeatism.

Teory of justifcation is a part of epistemology that attempts to understand the justifcation of propositions and beliefs. Epistemologists are concerned with various epistemic features of belief, which include the ideas of justifcation, warrant, rationality, and probability. Loosely speaking, justifcation is the reason that someone (properly) holds a belief.

149 When a claim is in doubt, justifcation can be used to support the claim and reduce or remove the doubt. Justifcation can use empiricism (the evidence of the senses), authoritative testimony (the appeal to criteria and authority), or logical deduction.

Nihilism (/ˈnaɪ.ɪlɪzəm/ or /ˈniːɪlɪzəm/; from the Latin nihil, nothing) is a philosophical doctrine that suggests the lack of belief in one or more reputedly meaningful aspects of life. Most commonly, nihilism is presented in the form of existential nihilism, which argues that life is without objective meaning, purpose, or intrinsic value. Moral nihilists assert that there is no inherent morality, and that accepted moral values are abstractly contrived. Nihilism may also take epistemological, ontological, or metaphysical forms, meaning respectively that, in some aspect, knowledge is not possible, or reality does not actually exist.

Te term is sometimes used in association with anomie to explain the general mood of despair at a perceived pointlessness of existence that one may develop upon realising there are no necessary norms, rules, or laws. Movements such as futurism and deconstruction, among others, have been identifed by commentators as "nihilistic".

Nihilism has also been described as conspicuous in or constitutive of certain historical periods: for example, Jean Baudrillard and others have called postmodernity a nihilistic epoch; and some religious theologians and fgures of religious authority have asserted that postmodernity and many aspects of modernity represent a rejection of theism, and that such rejection of theistic doctrine entails nihilism.

Narcissism is the pursuit of gratifcation from vanity or egotistic admiration of one's own attributes. Te term originated from Greek mythology, where the young Narcissus fell in love with his own image refected in a pool of water. Narcissism is a concept in psychoanalytic theory, which was popularly introduced in Sigmund Freud's essay On Narcissism (1914). Te American Psychiatric Association has listed the classifcation narcissistic personality disorder in its Diagnostic and Statistical Manual of Mental Disorders (DSM) since 1968, drawing on the historical concept of megalomania.

Narcissism is also considered a social or cultural problem. It is a factor in trait theory used in various self-report inventories of personality such as the Millon Clinical Multiaxial Inventory. It is one of the three dark triadic personality traits (the others being psychopathy and Machiavellianism). Except in the sense of primary narcissism or healthy self-love, narcissism is usually considered a problem in a person's or group's relationships with self and others. Narcissism is not the same as egocentrism.

Skepticism (American English) or scepticism (British English; see spelling diﬀerences) is generally any questioning attitude or doubt towards one or more items of putative knowledge or belief. It is often directed at domains, such as the supernatural, morality (moral skepticism), religion (skepticism about the existence of God), or knowledge (skepticism about the possibility of knowledge, or of certainty). Formally, skepticism as a topic occurs in the context of philosophy, particularly epistemology, although it can be applied to any topic such as politics, religion, and pseudoscience.

Philosophical skepticism comes in various forms. Radical forms of skepticism deny that knowledge or rational belief is possible and urge us to suspend judgment on many or all controversial matters. More moderate forms of skepticism claim only that nothing can be known with certainty, or that we can know little or nothing about the "big questions" in life, such as whether God exists or whether there is an afterlife. Religious skepticism is "doubt concerning basic religious principles (such as immortality, providence, and revelation)". Scientifc skepticism concerns testing beliefs for reliability, by subjecting them to systematic investigation using the scientifc method, to discover empirical evidence for them.

Solipsism (/ˈsɒlɪpsɪzəm/ (About this sound listen); from Latin solus, meaning 'alone', and ipse, meaning 'self')[1] is the philosophical idea that only one's own mind is sure to exist. As an epistemological position, solipsism holds that knowledge of anything outside one's own mind is unsure; the external world and other minds cannot be known and might not exist outside the mind. As a metaphysical position, solipsism goes further to the conclusion that the world and other minds do not exist.

Egalitarianism (from French égal, meaning 'equal') – or equalitarianism – is a school of thought that prioritizes equality for all people. According to the Stanford Encyclopedia of Philosophy, Egalitarian doctrines maintain that all humans are equal in fundamental worth or social status. According to the Merriam-Webster Dictionary, the term has two distinct defnitions in modern English: either as a political doctrine that all people should be treated as equals and have the same political, economic, social and civil rights; or as a social philosophy advocating the removal of economic inequalities among people, economic egalitarianism, or the decentralization of power. Some sources defne egalitarianism as the point of view that equality refects the natural state of humanity.[

150 Ontology is the philosophical study of the nature of being, becoming, existence, or reality, as well as the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology often deals with questions concerning what entities exist or may be said to exist and how such entities may be grouped, related within a hierarchy, and subdivided according to similarities and diﬀerences. A very simple defnition of ontology is that it is the examination of what is meant, in context, by the word ‘thing’.

In metaphysics, object-oriented ontology (OOO) is a 21st-century Heidegger-infuenced school of thought that rejects the privileging of human existence over the existence of nonhuman objects.[1] Tis is in contrast to what it calls the "anthropocentrism" of Kant's Copernican Revolution, as accepted by most other current metaphysics, in which phenomenal objects are said to conform to the mind of the subject and, in turn, become products of human cognition.[2] Object- oriented ontology maintains that objects exist independently (as Kantian noumena) of human perception and are not ontologically exhausted by their relations with humans or other objects.[3] Tus, for object-oriented ontologists, all relations, including those between nonhumans, distort their related objects in the same basic manner as human consciousness and exist on an equal footing with one another.[4]

Object-oriented ontology is often viewed as a subset of speculative realism, a contemporary school of thought that criticizes the post-Kantian reduction of philosophical enquiry to a correlation between thought and being, such that the reality of anything outside of this correlation is unknowable.[5] Object-oriented ontology predates speculative realism, however, and makes distinct claims about the nature and equality of object relations to which not all speculative realists agree. Te term "object-oriented philosophy" was coined by Graham Harman, the movement's founder, in his 1999 doctoral dissertation "Tool-Being: Elements in a Teory of Objects".[6][7] In 2009, Levi Bryant rephrased Harman's original designation as "object-oriented ontology", giving the movement its current name.

A synopsis is a brief summary of the major points of a subject or written work or story, either as prose or as a table; an abridgment or condensation of a work. Te etymology is from Greek syn- "together" + opsis "sight, appearance,". Used in English since 1610s.

A theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context, the results might, for example, include generalized explanations of how nature works. Te word has its roots in ancient Greek, but in modern use it has taken on several related meanings.

Teories guide the enterprise of fnding facts rather than of reaching goals, and are neutral concerning alternatives among values. A theory can be a body of knowledge, which may or may not be associated with particular explanatory models. To theorize is to develop this body of knowledge.

A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientifc hypothesis, the scientifc method requires that one can test it. Scientists generally base scientifc hypotheses on previous observations that cannot satisfactorily be explained with the available scientifc theories. Even though the words "hypothesis" and "theory" are often used synonymously, a scientifc hypothesis is not the same as a scientifc theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research.

A diﬀerent meaning of the term hypothesis is used in formal logic, to denote the antecedent of a proposition; thus in the proposition "If P, then Q", P denotes the hypothesis (or antecedent); Q can be called a consequent. P is the assumption in a (possibly counterfactual) What If question.

Te adjective hypothetical, meaning "having the nature of a hypothesis", or "being assumed to exist as an immediate consequence of a hypothesis", can refer to any of these meanings of the term "hypothesis".

Doctrine (from Latin: doctrina) is a codifcation of beliefs or a body of teachings or instructions, taught principles or positions, as the essence of teachings in a given branch of knowledge or belief system. Te Greek analogue is the etymology of catechism.

Often doctrine specifcally suggests a body of religious principles as it is promulgated by a church, but not necessarily; doctrine is also used to refer to a principle of law, in the common law traditions, established through a history of past decisions, such as the doctrine of self-defense, or the principle of fair use, or the more narrowly applicable frst-sale doctrine. In some organizations, doctrine is simply defned as "that which is taught", in other words the basis for institutional teaching of its personnel internal ways of doing business.

As already in Aristotle's defnitions, theory is very often contrasted to "practice" (from Greek praxis, πρᾶξις) a Greek term for doing, which is opposed to theory because pure theory involves no doing apart from itself. A classical example of the 151 distinction between "theoretical" and "practical" uses the discipline of medicine: medical theory involves trying to understand the causes and nature of health and sickness, while the practical side of medicine is trying to make people healthy. Tese two things are related but can be independent, because it is possible to research health and sickness without curing specifc patients, and it is possible to cure a patient without knowing how the cure worked.

A thought experiment (German: Gedankenexperiment, Gedanken-Experiment or Gedankenerfahrung) considers some hypothesis, theory, or principle for the purpose of thinking through its consequences. Given the structure of the experiment, it may not be possible to perform it, and even if it could be performed, there need not be an intention to perform it.

Te common goal of a thought experiment is to explore the potential consequences of the principle in question: "A thought experiment is a device with which one performs an intentional, structured process of intellectual deliberation in order to speculate, within a specifable problem domain, about potential consequents (or antecedents) for a designated antecedent (or consequent)"

Examples of thought experiments include Schrödinger's cat, illustrating quantum indeterminacy through the manipulation of a perfectly sealed environment and a tiny bit of radioactive substance, and Maxwell's demon, which attempts to demonstrate the ability of a hypothetical fnite being to violate the 2nd law of thermodynamics.

Schematic fgure of Maxwell's demon In the philosophy of thermal and statistical physics, Maxwell's demon is a thought experiment created by the physicist James Clerk Maxwell in which he suggested how the second law of thermodynamics might hypothetically be violated. In the thought experiment, a demon controls a small door between two chambers of gas. As individual gas molecules approach the door, the demon quickly opens and shuts the door so that fast molecules pass into the other chamber, while slow molecules remain in the frst chamber. Because faster molecules are hotter, the demon's behavior causes one chamber to warm up as the other cools, thus decreasing entropy and violating the second law of thermodynamics.

Transcendentalism is a philosophical movement that developed in the late 1820s and 1830s in the eastern United States. It arose as a reaction to or protest against the general state of intellectualism and spirituality at the time. Te doctrine of the Unitarian church as taught at Harvard Divinity School was of particular interest.

Transcendentalism emerged from English and German Romanticism, the Biblical criticism of Johann Gottfried Herder and Friedrich Schleiermacher, the skepticism of David Hume, and the transcendental philosophy of Immanuel Kant and German Idealism. Miller and Versluis regard Emanuel Swedenborg as a pervasive infuence on transcendentalism. It was also infuenced by Hindu texts on philosophy of the mind and spirituality, especially the Upanishads.

A core belief of transcendentalism is in the inherent goodness of people and nature. Adherents believe that society and its institutions have corrupted the purity of the individual, and they have faith that people are at their best when truly "self- reliant" and independent.

Transcendentalism emphasizes subjective intuition over objective empiricism. Adherents believe that individuals are capable of generating completely original insights with little attention and deference to past masters.

Romanticism (also the Romantic era or the Romantic period) was an artistic, literary, musical and intellectual movement that originated in Europe toward the end of the 18th century, and in most areas was at its peak in the approximate period from 1800 to 1850. Romanticism was characterized by its emphasis on emotion and individualism as well as glorifcation of all the past and nature, preferring the medieval rather than the classical. It was partly a reaction to the Industrial Revolution, the aristocratic social and political norms of the Age of Enlightenment, and the scientifc rationalization of nature—all components of modernity. It was embodied most strongly in the visual arts, music, and literature, but had a major impact on historiography, education, the social sciences, and the natural sciences. It had a signifcant and complex eﬀect on politics, with romantic thinkers infuencing liberalism, radicalism, conservatism and nationalism.

Te movement emphasized intense emotion as an authentic source of aesthetic experience, placing new emphasis on such emotions as apprehension, horror and terror, and awe—especially that experienced in confronting the new aesthetic categories of the sublimity and beauty of nature. It elevated folk art and ancient custom to something noble, but also spontaneity as a desirable characteristic (as in the musical impromptu). In contrast to the Rationalism and Classicism of the Enlightenment, Romanticism revived medievalism and elements of art and narrative perceived as authentically medieval in an attempt to escape population growth, early urban sprawl, and industrialism.

Although the movement was rooted in the German Sturm und Drang movement, which preferred intuition and emotion to the rationalism of the Enlightenment, the events and ideologies of the French Revolution were also proximate factors. 152 Romanticism assigned a high value to the achievements of "heroic" individualists and artists, whose examples, it maintained, would raise the quality of society. It also promoted the individual imagination as a critical authority allowed of freedom from classical notions of form in art. Tere was a strong recourse to historical and natural inevitability, a Zeitgeist, in the representation of its ideas. In the second half of the 19th century, Realism was oﬀered as a polar opposite to Romanticism. Te decline of Romanticism during this time was associated with multiple processes, including social and political changes and the spread of nationalism.

Materialism is a form of philosophical monism which holds that matter is the fundamental substance in nature, and that all things, including mental aspects and consciousness, are results of material interactions.

In Idealism, mind and consciousness are frst-order realities to which matter is subject and secondary. In philosophical materialism the converse is true. Here mind and consciousness are by-products or epiphenomena of material processes (the biochemistry of the human brain and nervous system, for example) without which they cannot exist. According to this doctrine the material creates and determines consciousness, not vice versa. Materialists believe that Matter and the physical laws that govern it constitute the most reliable guide to the nature of mind and consciousness.

Materialist theories are mainly divided into three groups. Naive materialism identifes the material world with specifc elements (e.g. the scheme of the four elements—fre, air, water and earth—devised by the Pre-Socratic philosopher Empedocles). Metaphysical materialism examines separated parts of the world in a static, isolated environment. Dialectical materialism adapts the Hegelian dialectic for materialism, examining parts of the world in relation to each other within a dynamic environment.

Materialism is closely related to physicalism, the view that all that exists is ultimately physical. Philosophical physicalism has evolved from materialism with the discoveries of the physical sciences to incorporate more sophisticated notions of physicality than mere ordinary matter, such as: spacetime, physical energies and forces, dark matter, and so on. Tus the term "physicalism" is preferred over "materialism" by some, while others use the terms as if they are synonymous.

Philosophies contradictory to materialism or physicalism include idealism, pluralism, dualism, and other forms of monism.

Ancient history is the aggregate of past events from the beginning of recorded human history and extending as far as the Early Middle Ages or the Postclassical Era. Te span of recorded history is roughly 5,000 years, beginning with Sumerian Cuneiform script, the oldest discovered form of coherent writing from the protoliterate period around the 30th century BC.

Mind–body dualism, or mind–body duality, is a view in the philosophy of mind that mental phenomena are, in some respects, non-physical, or that the mind and body are distinct and separable. Tus, it encompasses a set of views about the relationship between mind and matter, and between subject and object, and is contrasted with other positions, such as physicalism and enactivism, in the mind–body problem.

Aristotle shared Plato's view of multiple souls and further elaborated a hierarchical arrangement, corresponding to the distinctive functions of plants, animals, and people: a nutritive soul of growth and metabolism that all three share; a perceptive soul of pain, pleasure, and desire that only people and other animals share; and the faculty of reason that is unique to people only. In this view, a soul is the hylomorphic form of a viable organism, wherein each level of the hierarchy formally supervenes upon the substance of the preceding level. Tus, for Aristotle, all three souls perish when the living organism dies. For Plato however, the soul was not dependent on the physical body; he believed in metempsychosis, the migration of the soul to a new physical body.

Dualism is closely associated with the thought of René Descartes (1641), which holds that the mind is a nonphysical—and therefore, non-spatial—substance. Descartes clearly identifed the mind with consciousness and self-awareness and distinguished this from the brain as the seat of intelligence. Hence, he was the frst to formulate the mind–body problem in the form in which it exists today. Dualism is contrasted with various kinds of monism. Substance dualism is contrasted with all forms of materialism, but property dualism may be considered a form of emergent materialism or non-reductive physicalism in some sense.

Synergy is the creation of a whole that is greater than the simple sum of its parts. Te term synergy comes from the Attic Greek word συνεργία synergia[1] from synergos, συνεργός, meaning "working together".

Te term Dogma is used in pejorative and non-pejorative senses. Dogma is transliterated in the 17th century from Latin (Latin dogma) meaning "philosophical tenet", derived from the Greek 'dogma' (Greek δόγμα) meaning literally "that which one thinks is true" and 'dokein' (Greek dokeo) "to seem good."

153 In the non-pejorative sense, dogma is an oﬃcial system of principles or tenets of a church, such as Roman Catholicism, or the positions of a philosopher or of a philosophical school such as Stoicism.

In the pejorative sense, dogma refers to enforced decisions, such as those of aggressive political interests or authorities. More generally it is applied to some strong belief that the ones adhering to it are not willing to rationally discuss. Tis attitude is named as a dogmatic one, or as dogmatism, and is often used to refer to matters related to religion, but is not limited to theistic attitudes alone, and is often used with respect to political or philosophical dogmas.

Philosophy on the concepts of destiny and fate has existed since the Hellenistic period with groups such as the Stoics and the Epicureans.

Te Stoics believed that human decisions and actions ultimately went according to a divine plan devised by a god. Tey claimed that although humans theoretically have free will, their souls and the circumstances under which they live are all part of the universal network of fate.

Te Epicureans challenged the Stoic beliefs by denying the existence of this divine fate. Tey believed that a human’s actions were voluntary so long as they were rational.

In daily language, "destiny" and "fate" are synonymous, but with regard to 19th century philosophy, the words gained inherently diﬀerent meanings.

For Arthur Schopenhauer, destiny was just a manifestation of the Will to Live, which can be at the same time living fate and choice of overrunning fate, by means of the Art, of the Morality and of the Ascesis.

For Nietzsche, destiny keeps the form of Amor fati (Love of Fate) through the important element of Nietzsche's philosophy, the "will to power" (der Wille zur Macht), the basis of human behavior, infuenced by the Will to Live of Schopenhauer. But this concept may have even other senses, although he, in various places, saw the will to power as a strong element for adaptation or survival in a better way. Nietzsche eventually transformed the idea of matter as centers of force into matter as centers of will to power as humanity’s destiny to face with amor fati. Te expression Amor fati is used repeatedly by Nietzsche as acceptation-choice of the fate, but in such way it becomes even another thing, precisely a "choice" destiny.

Determinism is a philosophical concept often confused with fate, it can be defned as the notion that all intents/actions are causally determined by the culminations of an agent’s existing circumstances; simply put, everything that happens is determined by things that have already happened. Determinism diﬀers from fate in that it is never conceived as being a spiritual, religious, nor astrological notion; fate is typically thought of as being "given" or "decreed" while determinism is "caused." Infuential philosophers like Robert Kane (philosopher), Tomas Nagel, Roderick Chisholm, and A.J. Ayer have written about this notion.

Stoicism is a school of Hellenistic philosophy that fourished throughout the Roman and Greek world until the 3rd century AD. Stoicism is predominantly a philosophy of personal ethics which is informed by its system of logic and its views on the natural world. According to its teachings, as social beings, the path to happiness for humans is found in accepting this moment as it presents itself, by not allowing ourselves to be controlled by our desire for pleasure or our fear of pain, by using our minds to understand the world around us and to do our part in nature's plan, and by working together and treating others in a fair and just manner.

It was founded in Athens by Zeno of Citium in the early 3rd century BC. Te Stoics taught that emotions resulted in errors of judgment which were destructive, due to the active relationship between cosmic determinism and human freedom, and the belief that it is virtuous to maintain a will (called prohairesis) that is in accord with nature. Because of this, the Stoics presented their philosophy as a religion (lex divina), and they thought that the best indication of an individual's philosophy was not what a person said but how a person behaved. To live a good life, one had to understand the rules of the natural order since they taught that everything was rooted in nature.

Later Stoics—such as Seneca and Epictetus—emphasized that, because "virtue is suﬃcient for happiness", a sage was immune to misfortune. Tis belief is similar to the meaning of the phrase "stoic calm", though the phrase does not include the "radical ethical" Stoic views that only a sage can be considered truly free, and that all moral corruptions are equally vicious.

From its founding, Stoic doctrine was popular during the Roman Empire—and its adherents included the Emperor Marcus Aurelius. It later experienced a decline after Christianity became the state religion in the 4th century AD. Over the centuries, it has seen revivals, notably in the Renaissance (Neostoicism) and in the modern era (modern Stoicism).

154 Epicureanism is a system of philosophy based upon the teachings of the ancient Greek philosopher Epicurus, founded around 307 BC. Epicurus was an atomic materialist, following in the steps of Democritus. His materialism led him to a general attack on superstition and divine intervention. Following Aristippus— about whom very little is known—Epicurus believed that what he called "pleasure" was the greatest good, but that the way to attain such pleasure was to live modestly, to gain knowledge of the workings of the world, and to limit one's desires. Tis would lead one to attain a state of tranquility (ataraxia) and freedom from fear as well as an absence of bodily pain (aponia). Te combination of these two states constitutes happiness in its highest form. Although Epicureanism is a form of hedonism insofar as it declares pleasure to be its sole intrinsic goal, the concept that the absence of pain and fear constitutes the greatest pleasure, and its advocacy of a simple life, make it very diﬀerent from "hedonism" as colloquially understood.

Epicureanism was originally a challenge to Platonism, though later it became the main opponent of Stoicism. Epicurus and his followers shunned politics. After the death of Epicurus, his school was headed by Hermarchus; later many Epicurean societies fourished in the Late Hellenistic era and during the Roman era (such as those in Antiochia, Alexandria, Rhodes, and Ercolano). Its best-known Roman proponent was the poet Lucretius. By the end of the Roman Empire, being opposed by philosophies (mainly Neo-Platonism) that were now in the ascendant, Epicureanism had all but died out, and would be resurrected in the Age of Enlightenment.

Some writings by Epicurus have survived. Some scholars consider the epic poem On the Nature of Tings by Lucretius to present in one unifed work the core arguments and theories of Epicureanism. Many of the scrolls unearthed at the Villa of the Papyri at Herculaneum are Epicurean texts. At least some are thought to have belonged to the Epicurean Philodemus. Today, there are large Epicurean communities in Greece, a Society of Friends of Epicurus in the West, and the School has a growing online presence. In the French-speaking world, Michel Onfray is considered Neo-Epicurean.

Certainty is perfect knowledge that has total security from error, or the mental state of being without doubt.

Eugenics (/juːˈdʒɛnɪks/; from Greek εὐγενής eugenes 'well-born' from εὖ eu, 'good, well' and γένος genos, 'race, stock, kin') is a set of beliefs and practices that aims at improving the genetic quality of a human population. Te exact defnition of eugenics has been a matter of debate since the term was coined by Francis Galton in 1883. Te concept predates this coinage, with Plato suggesting applying the principles of selective breeding to humans around 400 BCE.

Ageing or aging (see spelling diﬀerences) is the process of becoming older. Te term refers especially to human beings, many animals, and fungi, whereas for example bacteria, perennial plants and some simple animals are potentially immortal. In the broader sense, ageing can refer to single cells within an organism which have ceased dividing (cellular senescence) or to the population of a species (population ageing).

While philosophical thought pertaining to science dates back at least to the time of Aristotle, philosophy of science emerged as a distinct discipline only in the middle of the 20th century in the wake of the logical positivism movement, which aimed to formulate criteria for ensuring all philosophical statements' meaningfulness and objectively assessing them. Tomas Kuhn's landmark 1962 book Te Structure of Scientifc Revolutions was also formative, challenging the view of scientifc progress as steady, cumulative acquisition of knowledge based on a fxed method of systematic experimentation and instead arguing that any progress is relative to a "paradigm," the set of questions, concepts, and practices that defne a scientifc discipline in a particular historical period.[1] Karl Popper and Charles Sanders Peirce moved on from positivism to establish a modern set of standards for scientifc methodology.

Philosophies of the particular sciences range from questions about the nature of time raised by Einstein's general relativity, to the implications of economics for public policy. A central theme is whether one scientifc discipline can be reduced to the terms of another. Tat is, can chemistry be reduced to physics, or can sociology be reduced to individual psychology? Te general questions of philosophy of science also arise with greater specifcity in some particular sciences. For instance, the question of the validity of scientifc reasoning is seen in a diﬀerent guise in the foundations of statistics. Te question of what counts as science and what should be excluded arises as a life-or-death matter in the philosophy of medicine. Additionally, the philosophies of biology, of psychology, and of the social sciences explore whether the scientifc studies of human nature can achieve objectivity or are inevitably shaped by values and by social relations.

Complexity characterises the behaviour of a system or model whose components interact in multiple ways and follow local rules, meaning there is no reasonable higher instruction to defne the various possible interactions.

155 Te stem of the word "complexity" - complex - combines the Latin roots com (meaning "together") and plex (meaning "woven"). Contrast "complicated" where plic (meaning "folded") refers to many layers. A complex system is thereby characterised by its inter-dependencies, whereas a complicated system is characterised by its layers.

Complexity is generally used to characterize something with many parts where those parts interact with each other in multiple ways, culminating in a higher order of emergence greater than the sum of its parts. Just as there is no absolute defnition of "intelligence", there is no absolute defnition of "complexity"; the only consensus among researchers is that there is no agreement about the specifc defnition of complexity. However, "a characterization of what is complex is possible". Te study of these complex linkages at various scales is the main goal of complex systems theory. Science takes a number of approaches to characterizing complexity; Zayed et al. refect many of these. Neil Johnson states that "even among scientists, there is no unique defnition of complexity – and the scientifc notion has traditionally been conveyed using particular examples..." Ultimately Johnson adopts the defnition of "complexity science" as "the study of the phenomena which emerge from a collection of interacting objects”.

In philosophy, systems theory, science, and art, emergence is a phenomenon whereby larger entities arise through interactions among smaller or simpler entities such that the larger entities exhibit properties the smaller/simpler entities do not exhibit.

Emergence plays a central role in theories of integrative levels and of complex systems. For instance, the phenomenon of life as studied in biology is an emergent property of chemistry, and psychological phenomena emerge from the neurobiological phenomena of living things.

In philosophy, theories that emphasize emergent properties have been called emergentism. Almost all accounts of emergentism include a form of epistemic or ontological irreducibility to the lower levels.

Groups of human beings, left free to each regulate themselves, tend to produce spontaneous order, rather than the meaningless chaos often feared. Tis has been observed in society at least since Chuang Tzu in ancient China. A classic traffic roundabout is a good example, with cars moving in and out with such effective organization that some modern cities have begun replacing stoplights at problem intersections with traffic circles, and getting better results. Open-source software and Wiki projects form an even more compelling illustration.

Emergent processes or behaviors can be seen in many other places, such as cities, cabal and market-dominant minority phenomena in economics, organizational phenome

Spontaneous order, also named self-organization in the hard sciences, is the spontaneous emergence of order out of seeming chaos. It is a process in social networks including economics, though the term "self-organization" is more often used for physical changes and biological processes, while "spontaneous order" is typically used to describe the emergence of various kinds of social orders from a combination of self-interested individuals who are not intentionally trying to create order through planning. Te evolution of life on Earth, language, crystal structure, the Internet and a free market economy have all been proposed as examples of systems which evolved through spontaneous order. Naturalists often point to the inherent "watch-like" precision of uncultivated ecosystems and to the universe itself as ultimate examples of this phenomenon.

Spontaneous orders are to be distinguished from organizations. Spontaneous orders are distinguished by being scale-free networks, while organizations are hierarchical networks. Further, organizations can be and often are a part of spontaneous social orders, but the reverse is not true. Further, while organizations are created and controlled by humans, spontaneous orders are created, controlled, and controllable by no one. In economics and the social sciences, spontaneous order is defned as "the result of human actions, not of human design".

Spontaneous order is also used as a synonym for any emergent behavior of which self-interested spontaneous order is just an instance.

Spontaneous order is an equilibrium behavior between self-interested individuals, which is most likely to evolve and survive, obeying the natural selection process "survival of the likeliest".

156 Emergence plays a central role in theories of integrative levels and of complex systems. For instance, the phenomenon of life as studied in biology is an emergent property of chemistry, and psychological phenomena emerge from the neurobiological phenomena of living things. Tere are 489 trillion chemicals in the human/cosmological body.

In philosophy, theories that emphasize emergent properties have been called[by whom?] emergentism. Almost all accounts of emergentism include a form of epistemic or ontological irreducibility to the lower levels.[1]

In philosophy, emergentism is the belief in emergence, particularly as it involves consciousness and the philosophy of mind, and as it contrasts (or not) with reductionism. A property of a system is said to be emergent if it is a new outcome of some other properties of the system and their interaction, while it is itself diﬀerent from them.[27] Emergent properties are not identical with, reducible to, or deducible from the other properties. Te diﬀerent ways in which this independence requirement can be satisfed lead to variant types of emergence.

Hylopathism argues for a similarly universal attribution of sentience to matter. Few writers would advocate a hylopathic materialism, although the idea is not new; it has been formulated as "whatever underlies consciousness in a material sense, i.e., whatever it is about the brain that gives rise to consciousness, must necessarily be present to some degree in any other material thing". A compound state of mind does not consist of compounded psychic atoms. Te concept of awareness "being in itself" allows for the idea of self-aware matter. Attempts have been made to conceptualize this primitive level of existence prior to associative learning and memory. In the way that the collection of self-aware matter constitutes a cognitive being, the collection of cognitive beings as a conglomerate entity, refects panpsychism. Consciousness was not "nascent" but emergent due to a lack of abandon during the evolution of material awareness.[26]

Similar ideas have been attributed to Australian philosopher David Chalmers, who assumes that consciousness is a fundamental feature of the Universe, what he refers to as the First Datum in the study of the mind. In the practice of non- reductionism this feature may not be attributable to any base monad but instead radically emergent on the level of physical complexity at which it demonstrates itself. Complex elegance is the further development of awareness that is self-aware. Tis we can call "post-intelligence" where "intelligence" is simple processing. Te element of superiority might be that the post-intelligence is proto-experiential. Tese phenomenal properties are called "the internal aspects of information".[26]:162–170

In philosophy, panpsychism is the view that consciousness, mind or soul (psyche) is a universal and primordial feature of all things. Panpsychists see themselves as minds in a world of mind.

Panpsychism is one of the oldest philosophical theories, and has been ascribed to philosophers like Tales, Parmenides, Plato, Averroes, Spinoza, Leibniz and William James. Panpsychism can also be seen in ancient philosophies such as Stoicism, Taoism, Vedanta and Mahayana Buddhism. During the 19th century, panpsychism was the default theory in philosophy of mind, but it saw a decline during the middle years of the 20th century with the rise of logical positivism.[1] [2] Te recent interest in the hard problem of consciousness has revived interest in panpsychism.[1]

Te term "panpsychism" has its origins with the Greek term pan (πᾶν : "all, everything, whole") and psyche (ψυχή: "soul, mind") as the unifying center of the mental life of us humans and other living creatures."[3] Psyche comes from the Greek word ψύχω (psukhō, "I blow") and can mean life, soul, mind, spirit, heart and 'life-breath'. Te use of psyche is controversial due to it being synonymous with soul, a term usually taken to have some sort of supernatural quality; more common terms now found in the literature include mind, mental properties, mental aspect, and experience.

One criticism of panpsychism is the simple lack of evidence that the physical entities have any mental attributes. John Searle states that panpsychism is an "absurd view" and that thermostats lack "enough structure even to be a remote candidate for consciousness" (Searle, 1997, p. 48).

Physicalists also could[original research?] argue against panpsychism by denying proposition (2) of Nagel's argument. If mental properties are reduced to physical properties of a physical system, then it does not follow that all matter has mental properties: it is in virtue of the structural or functional organization of the physical system that the system can be said to have a mind, not simply that it is made of matter. Tis is the common Functionalist position. Tis view allows for certain man-made systems that are properly organized, such as some computers, to be said to have minds. Tis may cause problems when (4) is taken into account. Also, qualia seem to undermine the reduction of mental properties to brain properties. [citation needed]

157 Some have argued that the only properties shared by all qualia are that they are not precisely describable, and thus are of indeterminate meaning within any philosophy which relies upon precise defnition according to these critics (that is, it tends to presuppose a defnition for mentality without describing it in any real detail). Te need to defne better the terms used within the thesis of panpsychism is recognized by panpsychist David Skrbina,[23] and he resorts to asserting some sort of hierarchy of mental terms to be used. Tis is motivation to argue for panexperientialism rather than panpsychism, since only the most fundamental meaning of mind is what is present in all matter, namely, subjective experience.

158 6) Science’s and Math

Science (from Latin scientia, meaning "knowledge")is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Biology breaks down too Chemistry, Chemistry breaks down too Physics and Physics breaks down too Math.

Natural science is a branch of science concerned with the description, prediction, and understanding of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeatability of fndings are used to try to ensure the validity of scientifc advances.

Natural science can be divided into two main branches: life science (or biological science) and physical science. Physical science is subdivided into branches, including physics, space science, chemistry, and Earth science. Tese branches of natural science may be further divided into more specialized branches (also known as felds).

In Western society's analytic tradition, the empirical sciences and especially natural sciences use tools from formal sciences, such as mathematics and logic, converting information about nature into measurements which can be explained as clear statements of the "laws of nature". Te social sciences also use such methods, but rely more on qualitative research, so that they are sometimes called "soft science", whereas natural sciences, insofar as they emphasize quantifable data produced, tested, and confrmed through the scientifc method, are sometimes called "hard science".

Modern natural science succeeded more classical approaches to natural philosophy, usually traced to ancient Greece. Galileo, Descartes, Francis Bacon, and Newton debated the benefts of using approaches which were more mathematical and more experimental in a methodical way. Still, philosophical perspectives, conjectures, and presuppositions, often overlooked, remain necessary in natural science. Systematic data collection, including discovery science, succeeded natural history, which emerged in the 16th century by describing and classifying plants, animals, minerals, and so on. Today, "natural history" suggests observational descriptions aimed at popular audiences.

In modern science, it is regarded as good scientifc practice to aim for principles such as objectivity and reproducibility, which means that improvised methodology or bizarre interpretations should be downplayed, at least unless the scientist rightfully suspects a paradigm change. It is seen as advantageous to not deviate too far from the scientifc method, which nonetheless is far more stringently applied in e.g. the medical sciences than in sociology. Te optimal way to conduct modern science is under constant debate in the philosophy of science. Te English term "science" often refers to a particularly formal kind of empirical research, whereas equivalent concepts in other languages may not distinguish as clearly between this and rationalist academic research. Te acceptance of the infuence of continental philosophy in modern science may diﬀer between countries and between individual universities. Advances in modern science are sometimes used to develop new technology, but also examine limits to technological development.

In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. Many other states are known to exist, such as glass or liquid crystal, and some only exist under extreme conditions, such as Bose–Einstein condensates, neutron-degenerate matter, and quark-gluon plasma, which only occur, respectively, in situations of extreme cold, extreme density, and extremely high-energy. Some other states are believed to be possible but remain theoretical for now. For a complete list of all exotic states of matter, see the list of states of matter.

Historically, the distinction is made based on qualitative diﬀerences in properties. Matter in the solid state maintains a fxed volume and shape, with component particles (atoms, molecules or ions) 1 of 111 close together and fxed into place. Matter in the liquid state maintains a fxed volume, but has a variable shape that adapts to ft its container. Its particles are still close together but move freely. Matter in the gaseous state has both variable volume and shape, adapting both to ft its container. Its particles are neither close together nor fxed in place. Matter in the plasma

159 state has variable volume and shape, but as well as neutral atoms, it contains a signifcant number of ions and electrons, both of which can move around freely.

Te term phase is sometimes used as a synonym for state of matter, but a system can contain several immiscible phases of the same state of matter.

Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). In solids molecules are closely packed. It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike liquid, a solid object does not fow to take on the shape of its container, nor does it expand to fll the entire volume available to it like a gas does. Te atoms in a solid are tightly bound to each other, either in a regular geometric lattice (crystalline solids, which include metals and ordinary ice) or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because in gases molecules are loosely packed.

Te branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials science is primarily concerned with the physical and chemical properties of solids. Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as the science of identifcation and chemical composition.

A liquid is a nearly incompressible fuid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a defnite volume but no fxed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Water is, by far, the most common liquid on Earth. Like a gas, a liquid is able to fow and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fll every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena.

Te density of a liquid is usually close to that of a solid, and much higher than in a gas. Terefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gases share the ability to fow, they are both called fuids. Although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist. Most known matter in the universe is in gaseous form (with traces of detectable solid matter) as interstellar clouds or in plasma form within stars.

Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture would contain a variety of pure gases much like the air. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. Tis separation usually makes a colorless gas invisible to the human observer. Te interaction of gas particles in the presence of electric and gravitational felds are considered negligible, as indicated by the constant velocity vectors in the image.

Te gaseous state of matter is found between the liquid and plasma states,[1] the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases[2] which are gaining increasing attention.[3] High-density atomic gases super cooled to incredibly low temperatures are classifed by their statistical behavior

2 of 111 as either a Bose gas or a Fermi gas. For a comprehensive listing of these exotic states of matter see list of states of matter.

Plasma (from Ancient Greek πλάσμα, meaning 'moldable substance'[1]) is one of the four fundamental states of matter, and was frst described by chemist Irving Langmuir[2] in the 1920s. [3] Plasma can be artifcially generated by heating or subjecting a neutral gas to a strong electromagnetic feld to the point where an ionized gaseous substance becomes increasingly electrically conductive, and long-range electromagnetic felds dominate the behaviour of the matter. [4]

Plasma and ionized gases have properties and display behaviours unlike those of the other states, and the transition between them is mostly a matter of nomenclature[2] and subject to interpretation. [5] Based on the surrounding environmental temperature and density, partially ionized or fully ionized forms of plasma may be produced. Neon signs and lightning are examples of partially ionized plasma.[6] Te Earth's ionosphere is a plasma and the magnetosphere contains plasma in the Earth's surrounding space environment. Te interior of the Sun is an example of fully ionized plasma,[7] along with the solar corona[8] and stars.[9] 160 Positive charges in ions are achieved by stripping away electrons orbiting the atomic nuclei, where the total number of electrons removed is related to either increasing temperature or the local density of other ionized matter. Tis also can be accompanied by the dissociation of molecular bonds,[10] though this process is distinctly diﬀerent from chemical processes of ion interactions in liquids or the behaviour of shared ions in metals. Te response of plasma to electromagnetic felds is used in many modern technological devices, such as plasma televisions or plasma etching.[11]

Plasma may be the most abundant form of ordinary matter in the universe,[12] although this hypothesis is currently tentative based on the existence and unknown properties of dark matter. Plasma is mostly associated with stars, extending to the rarefed intracluster medium and possibly the intergalactic regions.[13]

A state of matter is also characterized by phase transitions. A phase transition indicates a change in structure and can be recognized by an abrupt change in properties. A distinct state of matter can be defned as any set of states distinguished from any other set of states by a phase transition. Water can be said to have several distinct solid states.[4] Te appearance of superconductivity is associated with a phase transition, so there are superconductive states. Likewise, ferromagnetic states are demarcated by phase transitions and have distinctive properties. When the change of state occurs in stages the intermediate steps are called mesophases. Such phases have been exploited by the introduction of liquid crystal technology.

Te state or phase of a given set of matter can change depending on pressure and temperature conditions, transitioning to other phases as these conditions change to favor their existence; for example, solid transitions to liquid with an increase in temperature. Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point, boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons are so energized that they leave their parent atoms.

Forms of matter that are not composed of molecules and are organized by diﬀerent forces can also be considered diﬀerent states of matter. Superfuids (like Fermionic condensate) and the quark– gluon plasma are examples.

In a chemical equation, the state of matter of the chemicals may be shown as (s) for solid, (l) for liquid, and (g) for gas. An aqueous solution is denoted (aq). Matter in the plasma state is seldom used (if at all) in chemical equations, so there is no standard symbol to denote it. In the rare equations that plasma is used in plasma is symbolized as (p).

Biology:

161 Biology is the natural science that involves the study of life and living organisms, including their physical structure, chemical composition, function, development and evolution. Modern biology is a vast feld, composed of many branches. Despite the broad scope and the complexity of the science, there are certain unifying concepts that consolidate it into a single, coherent feld. Biology recognizes the cell as the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that propels the creation of new species. Living organisms are open systems that survive by transforming energy and decreasing their local entropy to maintain a stable and vital condition defned as homeostasis. See glossary of biology.

Sub-disciplines of biology are defned by the scale at which life is studied, the kinds of organisms studied, and the methods used to study them: biochemistry examines the rudimentary chemistry of life; molecular biology studies the complex interactions among biological molecules; cellular biology examines the basic building-block of all life, the cell; physiology examines the physical and chemical functions of tissues, organs, and organ systems; ecology examines how organisms interact in their environment; and evolutionary biology examines the processes that produced the diversity of life.

In biology, structures exist at all levels of organization, ranging hierarchically from the atomic and molecular to the cellular, tissue, organ, organismic, population and ecosystem level. Usually, a higher-level structure is composed of multiple copies of a lower-level structure.

Structural biology is concerned with the biomolecular structure of macromolecules, particularly proteins and nucleic acids. Te function of these molecules is determined by their shape as well as their composition, and their structure has multiple levels. Protein structure has a four-level hierarchy. Te primary structure is the sequence of amino acids that make it up. It has a peptide backbone made up of a repeated sequence of a nitrogen and two carbon atoms. Te secondary structure consists of repeated patterns determined by hydrogen bonding. Te two basic types are the α-helix and the β-pleated sheet. Te tertiary structure is a back and forth bending of the polypeptide chain, and the quaternary structure is the way that tertiary units come together and interact.

Te cell (from Latin cella, meaning "small room" is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, and cells are often called the "building blocks of life". Te study of cells is called cell biology.

Cells consist of cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Organisms can be classifed as unicellular (consisting of a single cell; including bacteria) or multicellular (including plants and animals).While the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion (1013) cells. Most plant and animal cells are visible only under a microscope, with dimensions between 1 and 100 micrometres.

Te cell was discovered by Robert Hooke in 1665, who named the biological units for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, frst developed in 1839 by Matthias Jakob Schleiden and Teodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, that all cells come from preexisting cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. Cells emerged on Earth at least 3.5 billion years ago.

Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells. Tey are found in multicellular organisms. In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from 4 of 111 the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues. In a developing embryo, stem cells can differentiate into all the specialized cells— ectoderm, endoderm and mesoderm (see induced pluripotent stem cells)—but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.

Cell signaling (cell signalling in British English) is part of any communication process that governs basic activities of cells and coordinates all cell actions. Te ability of cells to perceive and correctly respond to their microenvironment is the basis of development, tissue repair, and immunity, as well as normal tissue homeostasis. Errors in signaling interactions and cellular information processing are responsible for diseases such as cancer, autoimmunity, and diabetes. By understanding cell signaling, diseases may be treated more eﬀectively and, theoretically, artifcial tissues may be created.

Traditional work in biology has focused on studying individual parts of cell signaling pathways. Systems biology research helps us to understand the underlying structure of cell signaling networks and how changes in these networks may aﬀect the transmission and fow of information (signal transduction). Such networks are complex systems in their organization and 162 may exhibit a number of emergent properties including bistability and ultrasensitivity. Analysis of cell signaling networks requires a combination of experimental and theoretical approaches including the development and analysis of simulations and modeling.Long-range allostery is often a signifcant component of cell signaling events.

Cell death is the event of a biological cell ceasing to carry out its functions. Tis may be the result of the natural process of old cells dying and being replaced by new ones, or may result from such factors as disease, localized injury, or the death of the organism of which the cells are part. Kinds of cell death include the following: Programmed cell death (or PCD) is cell death mediated by an intracellular program. PCD is carried out in a regulated process, which usually confers advantage during an organism's life-cycle. For example, the diﬀerentiation of fngers and toes in a developing human embryo occurs because cells between the fngers apoptose; the result is that the digits are separate. PCD serves fundamental functions during both plant and metazoa (multicellular animals) tissue development. Apoptosis or Type I cell-death, and autophagy or Type II cell-death are both forms of programmed cell death, while necrosis is a non-physiological process that occurs as a result of infection or injury. Necrosis is cell death caused by external factors such as trauma or infection, and occurs in several diﬀerent forms. Recently a form of programmed necrosis, called necroptosis, has been recognized as an alternate form of programmed cell death. It is hypothesized that necroptosis can serve as a cell-death backup to apoptosis when the apoptosis signaling is blocked by endogenous or exogenous factors such as viruses or mutations. Mitotic catastrophe is a mode of cell death that is due to premature or inappropriate entry of cells into mitosis. It is the most common mode of cell death in cancer cells exposed to ionizing radiation and many other anti-cancer treatments. Autophagy is cytoplasmic, characterized by the formation of large vacuoles that eat away organelles in a specifc sequence prior to the destruction of the nucleus.[5] Apoptosis is the process of programmed cell death (PCD) that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. Tese changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. It is now thought that – in a developmental context – cells are induced to positively commit suicide whilst in a homeostatic context; the absence of certain survival factors may provide the impetus for suicide. Tere appears to be some variation in the morphology and indeed the biochemistry of these suicide pathways; some treading the path of "apoptosis", others following a more generalized pathway to deletion, but both usually being genetically and synthetically motivated. Tere is some evidence that certain symptoms of "apoptosis" such as endonuclease activation can be spuriously induced without engaging a genetic cascade, however, presumably true apoptosis and programmed cell death must be genetically mediated. It is also becoming clear that mitosis and apoptosis are toggled or linked in some way and that the balance achieved depends on signals received from appropriate growth or survival

5 of 111 factors Macroautophagy, often referred to as autophagy, is a catabolic process that results in the autophagosomic-lysosomal degradation of bulk cytoplasmic contents, abnormal protein aggregates, and excess or damaged organelles. Autophagy is generally activated by conditions of nutrient deprivation but has also been associated with physiological as well as pathological processes such as development, diﬀerentiation, neurodegenerative diseases, stress, infection and cancer. Other pathways of programmed cell death have been discovered. Called "non-apoptotic programmed cell-death" (or "caspase- independent programmed cell-death" or "necroptosis"), these alternative routes to death are as eﬃcient as apoptosis and can function as either backup mechanisms or the main type of PCD. Other forms of programmed cell death include anoikis, almost identical to apoptosis except in its induction; cornifcation, a form of cell death exclusive to the eyes; excitotoxicity; ferroptosis, an iron-dependent form of cell death and Wallerian degeneration. Plant cells undergo particular processes of PCD similar to autophagic cell death. However, some common features of PCD are highly conserved in both plants and metazoa. Activation-induced cell death (AICD) is a programmed cell death caused by the interaction of Fas receptor (Fas, CD95)and Fas ligand. It occurs as a result of repeated stimulation of specifc T-cell receptors (TCR) and it helps to maintain the periphery immune tolerance. Terefore, an alteration of the process may lead to autoimmune diseases. In the other words AICD is the negative regulator of activated T-lymphocytes. Ischemic cell death, or oncosis, is a form of accidental, or passive cell death that is often considered a lethal injury. Te process is characterized by mitochondrial swelling, cytoplasm vacuolization, and swelling of the nucleus and cytoplasm.[12] Immunogenic cell death or immunogenic apoptosis is a form of cell death caused by some cytostatic agents such as anthracyclines, oxaliplatin and bortezomib, or radiotherapy and photodynamic therapy (PDT). Pyroptosis is a highly infammatory form of programmed cell death that occurs most frequently upon infection with intracellular pathogens and is likely to form part of the antimicrobial response in myeloid cells. Te term "cell necrobiology" has been used to describe the life processes associated with morphological, biochemical, and molecular changes which predispose, precede, and accompany cell death, as well as the consequences and tissue response to cell death. Te word is derived from the Greek νεκρό meaning "death", βìο meaning "life", and λόγος meaning "the study of". Te term was initially coined to broadly defne investigations of the changes that accompany cell death, detected and measured by multiparameter fow- and laser scanning- cytometry. It has been used to describe the real-time changes during cell death, detected by fow cytometry

163 Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. Te reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy in the process, as weak so-called "high- energy" bonds are replaced by stronger bonds in the products. Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. Cellular respiration is considered an exothermic redox reaction which releases heat. Te overall reaction occurs in a series of biochemical steps, most of which are redox reactions themselves. Although cellular respiration is technically a combustion reaction, it clearly does not resemble one when it occurs in a living cell because of the slow release of energy from the series of reactions. Nutrients that are commonly used by animal and plant cells in respiration include sugar, amino acids and fatty acids, and the most common oxidizing agent (electron acceptor) is molecular oxygen (O2). Te chemical energy stored in ATP (its third phosphate group is weakly bonded to the rest of the molecule and is cheaply broken allowing stronger bonds to form, thereby transferring energy for use by the cell) can then be used to drive processes requiring energy, including biosynthesis, locomotion or transportation of molecules across cell membranes.

Autophagy (or autophagocytosis) (from the Ancient Greek αὐτόφαγος autóphagos, meaning "self- devouring" and κύτος kýtos, meaning "hollow") is the natural, regulated, destructive mechanism of the cell that disassembles unnecessary or dysfunctional components. Autophagy allows the orderly degradation and recycling of cellular components. In macroautophagy, targeted cytoplasmic constituents are isolated from the rest of the cell within a double-membraned vesicle known as an autophagosome. Te autophagosome eventually fuses with lysosomes and the contents are

6 of 111 degraded and recycled. Tree forms of autophagy are commonly described: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). In disease, autophagy has been seen as an adaptive response to stress, which promotes survival, whereas in other cases it appears to promote cell death and morbidity. In the extreme case of starvation, the breakdown of cellular components promotes cellular survival by maintaining cellular energy levels. Te name "autophagy" was coined by Belgian biochemist Christian de Duve in 1963. Te identifcation of autophagy-related genes in yeast in the 1990s let researchers fgure out the mechanisms of autophagy, and led to the award of the 2016 Nobel Prize in Physiology or Medicine to Japanese autophagy researcher Yoshinori Ohsumi.

Cell adhesion is the process by which cells interact and attach to a surface, substrate or another cell, mediated by interactions between molecules of the cell surface. Cell adhesion occurs from the action of transmembrane glycoproteins, called cell adhesion molecules. Examples of these proteins include selectins, integrins, syndecans, and cadherins. Cellular adhesion is essential in maintaining multicellular structure. Cellular adhesion can link cells in diﬀerent ways and can be involved in signal transduction. Cell adhesion is also essential for the pathogenesis of infectious organisms.

Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis), and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes (meiosis). Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. Homologous chromosomes are separated in the frst division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor. Prokaryotes undergo a vegetative cell division known as binary fssion, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.

For simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes. After growth, cell division by mitosis allows for continual construction and repair of the organism. Te human body experiences about 10 quadrillion cell divisions in a lifetime.

Te primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in chromosomes must be replicated, and the duplicated genome must be separated cleanly between cells. A great deal of cellular infrastructure is involved in keeping genomic information consistent between generations.

A gamete (from Ancient Greek γαμετή gamete from gamein "to marry") is a haploid cell that fuses with another haploid cell during fertilization (conception) in organisms that sexually reproduce. In species that produce two morphologically 164 distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete—called an ovum (or egg)—and a male produces the smaller tadpole-like type—called a sperm. Tis is an example of anisogamy or heterogamy, the condition in which females and males produce gametes of diﬀerent sizes (this is the case in humans; the human ovum has approximately 100,000 times the volume of a single human sperm cell). In contrast, isogamy is the state of gametes from both sexes being the same size and shape, and given arbitrary designators for mating type. Te name

7 of 111 gamete was introduced by the Austrian biologist Gregor Mendel. Gametes carry half the genetic information of an individual, one ploidy of each type, and are created through meiosis.

Oogenesis is the process of female gamete formation in animals. Tis process involves meiosis (including meiotic recombination) occurring in the diploid primary oocyte to produce the haploid ovum (gamete). Spermatogenesis is the process of male gamete formation in animals. Tis process also involves meiosis (including meiotic recombination) occurring in the diploid primary spermatocyte to produce the haploid spermatozoon (gamete).

A zygote (from Greek ζυγωτός zygōtos "joined" or "yoked", from ζυγοῦν zygoun "to join" or "to yoke") is a eukaryotic cell formed by a fertilization event between two gametes. Te zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information necessary to form a new individual. In multicellular organisms, the zygote is the earliest developmental stage. In single-celled organisms, the zygote can divide asexually by mitosis to produce identical oﬀspring.

Cell Physiology.. . Te relation of cell physiology to diﬀerent felds of physiology such as, animal physiology, comparative animal physiology, plant physiology and molecular biology are being fundamental parts of physiology feld. Animal physiology plays a role of the work of various organs of the body which those organs coordinate to integrate the animal behavior. medical men in were concerned about vertebrate organ physiology precisely with mammals, because the information provided could be benefcially applied to the physiology of human in health and diseases. it is a benefcial to work on organ physiology as an medical approach. However, the Cellular level can be used as well. In addition, Comparative animal physiology is a prat of studying the function of any organ in various types of animals such as, vertebrate and invertebrate to fnd the fundamental relations. Plant physiology is more likely concerns about the response, nutrition, growth and reproduction of diﬀerent types of plants. and Since the functioning of the animal and plant depend on the function of the cells component. All of these physiological studies have been recognized by researchers whom were interested in organisms and worked at the cellular level to solve problems at the organs levels. on the other hand, Molecular biology turns to explain the cells activities in at the molecular level.In the past time, it has been limited in studying activities of viruses and bacteria. However, now it is being extended on studying the activities of the Eukaryota cells. Molecular biology has been contributed as an aim for cell physiology by being as powerful source of mutants (this method has been applied to many issues in cell physiology) such as, transportation across the cell membrane and the nature of the membranes. However, many of the cell physiology problems have not been solved by the molecular approach.

Cell physiology (including cellular electrophysiology) is the biological study (which has been a very indispensable study in the last several years) about the activities that take place in a cell to keep it alive. Tis includes, among animal cells, plant cells and microorganisms. Te term "physiology" refers to all the normal functions that take place in a living organism. All of these activities in the cell could be counted as following ; nutrition, environmental response , cell growth , cell division , reproduction and differentiation. Te differences among the animal cell, plant cell and microorganisms shows the essential functional similarity even though those cells have different structures. Absorption of water by roots, production of food in the leaves, and growth of shoots towards light are examples of plant physiology. Te heterotrophic metabolism of food derived from plants and animals and the use of movement to obtain nutrients (even if the organism itself remains in a relatively stationary position) are characteristic of animal physiology.

Cell biology or cytology or cytobiology, (from the Greek κυτος, kytos, "vessel") is a branch of biology that studies the diﬀerent structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life. Cell biology explains the structure, organization of the organelles they contain, their physiological properties, metabolic processes, signaling pathways, life cycle, 8 of 111 and interactions with their environment. Tis is done both on a microscopic and molecular level as it encompasses prokaryotic cells and eukaryotic cells. Knowing the components of cells and how cells work is fundamental to all biological

165 sciences; it is also essential for research in bio-medical felds such as cancer, and other diseases. Research in cell biology is closely related to genetics, biochemistry, molecular biology, immunology, and developmental biology.

In the context of human physiology, the term cell physiology often specifcally applies to the physiology of membrane transport, neuron transmission, and (less frequently) muscle contraction. In general, these cover the digestion of food, circulation of blood, and contraction of muscles and, therefore, are important aspects of human physiology. For a more complete description of the general physiological function of human cells (as well as the cells of other life forms), see the article on cell biology.

Experimental approach in cell physiology is an important aspect in cell physiology because it utilizes the experimental methods in order to solve any scientifc issue related to physiology. the following examples have been studied in cellular problems by using the experimental method: First, the key of understanding cells' activities in animal, plant cells and microorganisms was studied by identifed the nature of organization of cells. Second, the diﬀerences of the environment plays a role of the nature of the cell environment, cell resistance and the adjustment. Tird, the nature of the cell in regulating and transporting materials into and out the cells crossing the cell membrane. Fourth, Cell foods and its inter- conversions and the mechanism of respiration process to release energy from cell's food. Fifth, the use of energy in respiration in terms of performing the variety types of work. For example, maintenance, readiness, osmotic and for manufacturing of secretions.

In cell biology, mitosis is a part of the cell cycle when replicated chromosomes are separated into two new nuclei. In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA is replicated) and is often accompanied or followed by cytokinesis, which divides the cytoplasm, organelles and cell membrane into two new cells containing roughly equal shares of these cellular components. Mitosis and cytokinesis together defne the mitotic (M) phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. Te process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. Tese stages are prophase, prometaphase, metaphase, anaphase, and telophase. During mitosis, the chromosomes, which have already duplicated, condense and attach to spindle fbers that pull one copy of each chromosome to opposite sides of the cell. Te result is two genetically identical daughter nuclei. Te rest of the cell may then continue to divide by cytokinesis to produce two daughter cells. Producing three or more daughter cells instead of normal two is a mitotic error called tripolar mitosis or multipolar mitosis (direct cell triplication / multiplication). Other errors during mitosis can induce apoptosis (programmed cell death) or cause mutations. Certain types of cancer can arise from such mutations. Mitosis occurs only in eukaryotic cells. Prokaryotic cells, which lack a nucleus, divide by a diﬀerent process called binary fssion. Mitosis varies between organisms. For example, animal cells undergo an "open" mitosis, where the nuclear envelope breaks down before the chromosomes separate, whereas fungi undergo a "closed" mitosis, where chromosomes divide within an intact cell nucleus. Most animal cells undergo a shape change, known as mitotic cell rounding, to adopt a near spherical morphology at the start of mitosis. Most human cells are produced by mitotic cell division. Important exceptions include the gametes – sperm and egg cells – which are produced by meiosis.

Meiosis /maɪˈoʊsɪs/ (About this sound listen) is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them. Tis process occurs in all sexually reproducing single-celled and multicellular eukaryotes, including animals, plants, and fungi. Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of 9 of 111 developmental disabilities.[6] In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. Te two meiotic divisions are known as Meiosis I and Meiosis II. Before meiosis begins, during S phase of the cell cycle, the DNA of each chromosome is replicated so that it consists of two identical sister chromatids, which remain held together through sister chromatid cohesion. Tis S- phase can be referred to as "premeiotic S-phase" or "meiotic S-phase". Immediately following DNA replication, meiotic cells enter a prolonged G2-like stage known as meiotic prophase. During this time, homologous chromosomes pair with each other and undergo genetic recombination, a programmed process in which DNA is cut and then repaired, which allows them to exchange some of their genetic information. A subset of recombination events results in crossovers, which create physical links known as chiasmata (singular: chiasma, for the Greek letter Chi (X)) between the homologous chromosomes. In most organisms, these links are essential to direct each pair of homologous chromosomes to segregate away from each other during Meiosis I, resulting in two haploid cells that have half the number of chromosomes as the parent cell. During Meiosis II, the cohesion between sister chromatids is released and they segregate from one another, as during mitosis. In some cases all four of the meiotic products form gametes such as sperm, spores, or pollen. In female animals, three of the four meiotic products are typically eliminated by extrusion into polar bodies, and only one cell develops to produce an ovum. Because the number of chromosomes is halved during meiosis, gametes can fuse (i.e. fertilization) to form a diploid zygote that contains two copies of each chromosome, one from each parent. Tus, alternating cycles of meiosis and fertilization enable sexual reproduction, with successive generations maintaining the same number of chromosomes. For 166 example, diploid human cells contain 23 pairs of chromosomes including 1 pair of sex chromosomes (46 total), half of maternal origin and half of paternal origin. Meiosis produces haploid gametes (ova or sperm) that contain one set of 23 chromosomes. When two gametes (an egg and a sperm) fuse, the resulting zygote is once again diploid, with the mother and father each contributing 23 chromosomes. Tis same pattern, but not the same number of chromosomes, occurs in all organisms that utilize meiosis.

Cholesterol, from the Ancient Greek chole- (bile) and stereos (solid) followed by the chemical suﬃx -ol for an alcohol, is an organic molecule. It is a sterol (or modifed steroid), a type of lipid molecule, and is biosynthesized by all animal cells, because it is an essential structural component of all animal cell membranes and is essential to maintain both membrane structural integrity and fuidity. Cholesterol allows animal cells to function without a cell wall (which in other species protects membrane integrity and cell viability); this allows animal cells to change shape rapidly.

In addition to its importance for animal cell structure, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid, and vitamin D. Cholesterol is the principal sterol synthesized by all animals. In vertebrates, hepatic cells typically produce the greatest amounts. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as Mycoplasma, which require cholesterol for growth. genetics

Genetics is the study of genes—what they are, what they do, and how they work. Genes inside the nucleus of a cell are strung together in such a way that the sequence carries information: that information determines how living organisms inherit various features (phenotypic traits). For example, oﬀspring produced by sexual reproduction usually look similar to each of their parents because they have inherited some of each of their parents' genes. Genetics identifes which features are inherited, and explains how these features pass from generation to generation. In addition to inheritance, genetics studies how genes are turned on and oﬀ to control what substances are made in a cell—gene expression; and how a cell divides— mitosis or meiosis.

Some phenotypic traits can be seen, such as eye color while others can only be detected, such as blood type or intelligence. Traits determined by genes can be modifed by the animal's 1 0 o f 1 1 1 surroundings (environment): for example, the general design of a tiger's stripes is inherited, but the specifc stripe pattern is determined by the tiger's surroundings. Another example is a person's height: it is determined by both genetics and nutrition.

Chromosomes are tiny packages which contain one DNA molecule and its associated proteins. Humans have 46 chromosomes (23 pairs). Tis number varies between species—for example, many primates have 24 pairs. Meiosis creates special cells, sperm in males and eggs in females, which only have 23 chromosomes. Tese two cells merge into one during the fertilization stage of sexual reproduction, creating a zygote. In a zygote, a nucleic acid double helix divides, with each single helix occupying one of the daughter cells, resulting in half the normal number of genes. By the time the zygote divides again, genetic recombination has created a new embryo with 23 pairs of chromosomes, half from each parent. Mating and resultant mate choice result in sexual selection. In normal cell division (mitosis) is possible when the double helix separates, and a complement of each separated half is made, resulting in two identical double helices in one cell, with each occupying one of the two new daughter cells created when the cell divides.

Chromosomes all contain DNA made up of four nucleotides, abbreviated C (cytosine), G (guanine), A (adenine), or T (thymine), which line up in a particular sequence and make a long string. Tere are two strings of nucleotides coiled around one another in each chromosome: a double helix. C on one string is always opposite from G on the other string; A is always opposite T. Tere are about 3.2 billion nucleotide pairs on all the human chromosomes: this is the human genome. Te order of the nucleotides carries genetic information, whose rules are defned by the genetic code, similar to how the order of letters on a page of text carries information. Tree nucleotides in a row—a triplet —carry one unit of information: a codon.

Cytosine (/ˈsaɪtəˌsiːn, -ˌziːn, -ˌsɪn/; C) is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2). Te nucleoside of cytosine is cytidine. In Watson-Crick base pairing, it forms three(3) hydrogen bonds with guanine.

Adenine /ˈædɪnɪn/ (A, Ade) is a nucleobase (a purine derivative). Its derivatives have a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and favin adenine dinucleotide (FAD). It also has functions in protein synthesis 167 and as a chemical component of DNA and RNA. Te shape of adenine is complementary to either thymine in DNA or uracil in RNA.

Te image on the right shows pure adenine, as an independent molecule. When connected into DNA, a covalent bond is formed between deoxyribose sugar and the bottom left nitrogen, so removing the hydrogen. Te remaining structure is called an adenine residue, as part of a larger molecule. Adenosine is adenine reacted with ribose as used in RNA and ATP; deoxyadenosine, adenine attached to deoxyribose, as is used to form DNA.

Guanine (/ˈɡwɑːnɪn/; or G, Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine (uracil in RNA). In DNA, guanine is paired with cytosine. Te guanine nucleoside is called guanosine.

With the formula C5H5N5O, guanine is a derivative of purine, consisting of a fused pyrimidine- imidazole ring system with conjugated double bonds. Being unsaturated, the bicyclic molecule is planar.

Tymine /ˈθaɪmɪn/ (T, Ty) is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G– C–A–T. Te others are adenine, guanine, and cytosine. Tymine is also known as 5-methyluracil, a pyrimidine nucleobase. In RNA, thymine is replaced by the nucleobase uracil. Tymine was frst isolated in 1893 by Albrecht Kossel and Albert Neumann from calves' thymus glands, hence its name.

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Te genetic code not only controls inheritance: it also controls gene expression, which occurs when a portion of the double helix is uncoiled, exposing a series of the nucleotides, which are within the interior of the DNA. Tis series of exposed triplets (codons) carries the information to allow machinery in the cell to "read" the codons on the exposed DNA, which results in the making of RNA molecules. RNA in turn makes either amino acids or microRNA, which are responsible for all of the structure and function of a living organism; i.e. they determine all the features of the cell and thus the entire individual. Closing the uncoiled segment turns oﬀ the gene.

Heritability means the information in a given gene is not always exactly the same in every individual in that species, so the same gene in different individuals does not give exactly the same instructions. Each unique form of a single gene is called an allele; different forms are collectively called polymorphisms. As an example, one allele for the gene for hair color and skin cell pigmentation could instruct the body to produce black pigment, producing black hair and pigmented skin; while a different allele of the same gene in a different individual could give garbled instructions that would result in a failure to produce any pigment, giving white hair and no pigmented skin: albinism. Mutations are random changes in genes creating new alleles, which in turn produce new traits, which could help, harm, or have no new effect on the individual's likelihood of survival; thus, mutations are the basis for evolution.

DNA repair is a collection of processes by which a cell identifes and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in as many as 1 million individual molecular lesions per cell per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. When normal repair processes fail, and when cellular apoptosis does not occur, irreparable DNA damage may occur, including double-strand breaks and DNA crosslinkages (interstrand crosslinks or ICLs).[2][3] Tis can eventually lead to malignant tumors, or cancer as per the two hit hypothesis. Te rate of DNA repair is dependent on many factors, including the cell type, the age of the cell, and the extracellular environment. A cell that has accumulated a large amount of DNA damage, or one that no longer effectively repairs damage incurred to its DNA, can enter one of three possible states: an irreversible state of dormancy, known as senescence cell suicide, also known as apoptosis or programmed cell death unregulated cell division, which can lead to the formation of a tumor that is cancerous Te DNA repair ability of a cell is vital to the integrity of its genome and thus to the normal functionality of that organism. Many genes that were initially shown to infuence life span have turned out to be involved in DNA damage repair and protection.

A biomolecule or biological molecule is a loosely used term for molecules or more commonly ions that are present in organisms. Biomolecules including large macromolecules (or polyanions) such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as primary metabolites, secondary metabolites, and natural products. A more general name for this class of material is biological materials. Biomolecules are usually endogenous but may also be exogenous. For example, pharmaceutical drugs may be natural products or semisynthetic (biopharmaceuticals) or they may be totally synthetic. 168 1 2 o f 1 1 1

Biology and its subsets of biochemistry and molecular biology study biomolecules and their reactions. Most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human body's mass. But many other elements, such as the various biometals, are present in small amounts.

Te uniformity of specifc types of molecules (the biomolecules) and of some metabolic pathways as invariant features between the diversity of life forms is called "biochemical universals" or "theory of material unity of the living beings", a unifying concept in biology, along with cell theory and evolution theory.

Metabolism (from Greek: μεταβολή metabolē, "change") is the set of life-sustaining chemical transformations within the cells of organisms. Te three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. Tese enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Te word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism. Metabolism is usually divided into two categories: catabolism, the breaking down of organic matter for example, the breaking down of glucose to pyruvate, by cellular respiration, and anabolism, the building up of components of cells such as proteins and nucleic acids. Usually, breaking down releases energy and building up consumes energy. Te chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy that will not occur by themselves, by coupling them to spontaneous reactions that release energy. Enzymes act as catalysts that allow the reactions to proceed more rapidly. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or to signals from other cells. Te metabolic system of a particular organism determines which substances it will fnd nutritious and which poisonous. For example, some prokaryotes use hydrogen sulfde as a nutrient, yet this gas is poisonous to animals. Te speed of metabolism, the metabolic rate, infuences how much food an organism will require, and also affects how it is able to obtain that food. A striking feature of metabolism is the similarity of the basic metabolic pathways and components between even vastly different species. For example, the set of carboxylic acids that are best known as the intermediates in the citric acid cycle are present in all known organisms, being found in species as diverse as the unicellular bacterium Escherichia coli and huge multicellular organisms like elephants.[3] Tese striking similarities in metabolic pathways are likely due to their early appearance in evolutionary history, and their retention because of their efficacy.

Metabolite is the intermediate and product of metabolism. Te term metabolite is usually restricted to small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory eﬀects on enzymes, catalytic activity of their own (usually as a cofactor to an enzyme), defense, and interactions with other organisms (e.g. pigments, odorants, and pheromones). A primary metabolite is directly involved in normal "growth", development, and reproduction. Ethylene is an example of a primary metabolite produced in large-scale by industrial microbiology. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments such as resins and terpenes etc. Some antibiotics use primary metabolites as precursors, such as actinomycin which is created from the primary metabolite, tryptophan. Some sugars are metabolites, such as fructose or glucose, which are both present in the metabolic pathways.

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Te metabolome forms a large network of metabolic reactions, where outputs from one enzymatic chemical reaction are inputs to other chemical reactions.

Metabolites from chemical compounds, whether inherent or pharmaceutical, are formed as part of the natural biochemical process of degrading and eliminating the compounds.Te rate of degradation of a compound is an important determinant of the duration and intensity of its action. Profling metabolites of pharmaceutical compounds, drug metabolism, is an important part of drug discovery, leading to an understanding of any undesirable side eﬀects.

A hormone (from the Greek participle “ὁρμῶ”, "to set in motion, urge on") is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour. Hormones have diverse chemical structures, mainly of 3 classes: eicosanoids, steroids, and amino acid/protein derivatives (amines, peptides, and proteins). Te glands that secrete hormones comprise the endocrine signaling system. Te term hormone is sometimes extended to include chemicals produced by cells that affect the same cell (autocrine or intracrine signalling) or nearby cells (paracrine signalling). 169 Hormones are used to communicate between organs and tissues for physiological regulation and behavioral activities, such as digestion, metabolism, respiration, tissue function, sensory perception, sleep, excretion, lactation, stress, growth and development, movement, reproduction, and mood. Hormones affect distant cells by binding to specifc receptor proteins in the target cell resulting in a change in cell function. When a hormone binds to the receptor, it results in the activation of a signal transduction pathway. Tis may lead to cell type-specifc responses that include rapid non-genomic effects or slower genomic responses where the hormones acting through their receptors activate gene transcription resulting in increased expression of target proteins. Amino acid–based hormones (amines and peptide or protein hormones) are water- soluble and act on the surface of target cells via second messengers; steroid hormones, being lipid-soluble, move through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei.

Hormone secretion may occur in many tissues. Endocrine glands are the cardinal example, but specialized cells in various other organs also secrete hormones. Hormone secretion occurs in response to specifc biochemical signals from a wide range of regulatory systems. For instance, serum calcium concentration aﬀects parathyroid hormone synthesis; blood sugar (serum glucose concentration) aﬀects insulin synthesis; and because the outputs of the stomach and exocrine pancreas (the amounts of gastric juice and pancreatic juice) become the input of the small intestine, the small intestine secretes hormones to stimulate or inhibit the stomach and pancreas based on how busy it is. Regulation of hormone synthesis of gonadal hormones, adrenocortical hormones, and thyroid hormones is often dependent on complex sets of direct infuence and feedback interactions involving the hypothalamic-pituitary-adrenal (HPA), -gonadal (HPG), and - thyroid (HPT) axes.

Upon secretion, certain hormones, including protein hormones and catecholamines, are water- soluble and are thus readily transported through the circulatory system. Other hormones, including steroid and thyroid hormones, are lipid-soluble; to allow for their widespread distribution, these hormones must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form ligand-protein complexes. Some hormones are completely active when released into the bloodstream (as is the case for insulin and growth hormones), while others are prohormones that must be activated in specifc cells through a series of activation steps that are commonly highly regulated. Te endocrine system secretes hormones directly into the bloodstream typically into fenestrated capillaries, whereas the exocrine system secretes its hormones indirectly using ducts. Hormones with paracrine function diﬀuse through the interstitial spaces to nearby target tissue.

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Amino acids contain both amino and carboxylic acid functional groups. (In biochemistry, the term amino acid is used when referring to those amino acids in which the amino and carboxylate functionalities are attached to the same carbon, plus proline which is not actually an amino acid).

Modifed amino acids are sometimes observed in proteins; this is usually the result of enzymatic modifcation after translation (protein synthesis). For example, phosphorylation of serine by kinases and dephosphorylation by phosphatases is an important control mechanism in the cell cycle. Only two amino acids other than the standard twenty are known to be incorporated into proteins during translation, in certain organisms:

Proteins (/ˈproʊˌtiːnz/ or /ˈproʊti.ɪnz/) are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, and transporting molecules from one location to another. Proteins diﬀer from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specifc three-dimensional structure that determines its activity.

A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. Te individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. Te sequence of amino acid residues in a protein is defned by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifes 20 standard amino acids; however, in certain organisms the genetic code can include selenocysteine and—in certain archaea—pyrrolysine. Shortly after or even during synthesis, the residues in a protein are often chemically modifed by post-translational modifcation, which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors. Proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes.

Once formed, proteins only exist for a certain period of time and are then degraded and recycled by the cell's machinery through the process of protein turnover. A protein's lifespan is measured in terms of its half-life and covers a wide range.

170 Tey can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal or misfolded proteins are degraded more rapidly either due to being targeted for destruction or due to being unstable.

Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms and participate in virtually every process within cells. Many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, which form a system of scaﬀolding that maintains cell shape. Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized. Digestion breaks the proteins down for use in the metabolism.

Proteins may be purifed from other cellular components using a variety of techniques such as ultracentrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic engineering has made possible a number of methods to facilitate purifcation. Methods commonly used to study protein structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance and mass spectrometry.

Te overall, compact, 3D structure of a protein is termed its tertiary structure or its "fold". It is formed as result of various attractive forces like hydrogen bonding, disulfde bridges, hydrophobic interactions, hydrophilic interactions, van der Waals force etc.

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Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate chemical reactions. Te molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into diﬀerent molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life.Metabolic pathways depend upon enzymes to catalyze individual steps. Te study of enzymes is called enzymology and a new feld of pseudoenzyme analysis has recently grown up, recognising that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often refected in their amino acid sequences and unusual 'pseudocatalytic' properties.

Enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules. Te latter are called ribozymes. Enzymes' specifcity comes from their unique three-dimensional structures.

Like all catalysts, enzymes increase the reaction rate by lowering its activation energy. Some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes diﬀer from most other catalysts by being much more specifc. Enzyme activity can be aﬀected by other molecules: inhibitors are molecules that decrease enzyme activity, and activators are molecules that increase activity. Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH.

Some enzymes are used commercially, for example, in the synthesis of antibiotics. Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, and enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.

A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen– oxygen atom ratio of 2:1 (as in water); in other words, with the empirical formula Cm(H2O)n (where m could be diﬀerent from n). Tis formula holds true for monosaccharides. Some exceptions exist; for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Te carbohydrates are technically hydrates of carbon; structurally it is more accurate to view them as polyhydroxy aldehydes and ketones.

Te term is most common in biochemistry, where it is a synonym of 'saccharide', a group that includes sugars, starch, and cellulose. Te saccharides are divided into four chemical groups: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest (lower molecular weight) carbohydrates, are commonly referred to as sugars.[6] Te word saccharide comes from the Greek word σάκχαρον (sákkharon), meaning "sugar".[7] While the scientifc nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suﬃx -ose. For example, grape sugar is the monosaccharide glucose, cane sugar is the disaccharide sucrose, and milk sugar is the disaccharide lactose.

171 Carbohydrates perform numerous roles in living organisms. Polysaccharides serve for the storage of energy (e.g. starch and glycogen) and as structural components (e.g. cellulose in plants and chitin in arthropods). Te 5-carbon monosaccharide ribose is an important component of coenzymes (e.g. ATP, FAD and NAD) and the backbone of the genetic molecule known as RNA. Te related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the immune system, fertilization, preventing pathogenesis, blood clotting, and development.

Carbohydrates are found in a wide variety of foods. Te important sources are cereals (wheat, maize, rice), potatoes, sugarcane, fruits, table sugar (sucrose), bread, milk, etc. Starch and sugar are the important carbohydrates in our diet. Starch is abundant in potatoes, maize, rice and other 1 6 o f 1 1 1 cereals. Sugar appears in our diet mainly as sucrose (table sugar), which is added to drinks and many prepared foods such as jam, biscuits and cakes, and glucose and fructose which occur naturally in many fruits and some vegetables.

Glycogen is a carbohydrate found in the liver and muscles (as animal source). Cellulose in the cell wall of all plant tissue is a carbohydrate. It is important in our diet as fbre which helps to maintain a healthy digestive system.

Nutrition is the science that interprets the interaction of nutrients and other substances in food in relation to maintenance, growth, reproduction, health and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism, and excretion.

A nutrient is a substance used by an organism to survive, grow, and reproduce. Te requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures, such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted to smaller molecules in the process of releasing energy, such as for carbohydrates, lipids, proteins, and fermentation products (ethanol or vinegar), leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.

Different types of organism have different essential nutrients. Ascorbic acid (vitamin C) is essential, meaning it must be consumed in sufficient amounts, to humans and some other animal species, but not to all animals and not to plants, which are able to synthesize it. Nutrients may be organic or inorganic: organic compounds include most compounds containing carbon, while all other chemicals are inorganic. Inorganic nutrients include nutrients such as iron, selenium, and zinc, while organic nutrients include, among many others, energy-providing compounds and vitamins.

A classifcation used primarily to describe nutrient needs of animals divides nutrients into macronutrients and micronutrients. Consumed in relatively large amounts (grams or ounces), macronutrients (carbohydrates, fats, proteins, water) are used primarily to generate energy or to incorporate into tissues for growth and repair. Micronutrients are needed in smaller amounts (milligrams or micrograms); they have subtle biochemical and physiological roles in cellular processes, like vascular functions or nerve conduction. Inadequate amounts of essential nutrients, or diseases that interfere with absorption, result in a defciency state that compromises growth, survival and reproduction. Consumer advisories for dietary nutrient intakes, such as the United States Dietary Reference Intake, are based on defciency outcomes[clarifcation needed] and provide macronutrient and micronutrient guides for both lower and upper limits of intake. In many countries, macronutrients and micronutrients in signifcant content[clarifcation needed] are required by regulations to be displayed on food product labels. Nutrients in larger quantities than the body needs may have harmful eﬀects. Edible plants also contain thousands of compounds generally called phytochemicals which have unknown eﬀects on disease or health, including a diverse class with non-nutrient status called polyphenols, which remain poorly understood as of 2017.

Plant nutrients consist of more than a dozen minerals absorbed through roots, plus carbon dioxide and oxygen absorbed or released through leaves. All organisms obtain all their nutrients from the surrounding environment.

Evolution is change in the heritable characteristics of biological populations over successive generations. Evolutionary processes give rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. 1 7 o f 1 1 1

Repeated formation of new species (speciation), change within species (anagenesis), and loss of species (extinction) throughout the evolutionary history of life on Earth are demonstrated by shared sets of morphological and biochemical

172 traits, including shared DNA sequences. Tese shared traits are more similar among species that share a more recent common ancestor, and can be used to reconstruct a biological "tree of life" based on evolutionary relationships (phylogenetics), using both existing species and fossils. Te fossil record includes a progression from early biogenic graphite, to microbial mat fossils, to fossilised multicellular organisms. Existing patterns of biodiversity have been shaped both by speciation and by extinction.

In the mid-19th century, Charles Darwin formulated the scientifc theory of evolution by natural selection, published in his book On the Origin of Species (1859). Evolution by natural selection is a process frst demonstrated by the observation that often, more offspring are produced than can possibly survive. Tis is followed by three observable facts about living organisms: 1) traits vary among individuals with respect to morphology, physiology, and behaviour (phenotypic variation), 2) different traits confer different rates of survival and reproduction (differential ftness), and 3) traits can be passed from generation to generation (heritability of ftness). Tus, in successive generations members of a population are replaced by progeny of parents better adapted to survive and reproduce in the biophysical environment in which natural selection takes place.

Tis teleonomy is the quality whereby the process of natural selection creates and preserves traits that are seemingly ftted for the functional roles they perform. Te processes by which the changes occur, from one generation to another, are called evolutionary processes or mechanisms. Te four most widely recognised evolutionary processes are natural selection (including sexual selection), genetic drift, mutation and gene migration due to genetic admixture. Natural selection and genetic drift sort variation; mutation and gene migration create variation.

Consequences of selection can include meiotic drive (unequal transmission of certain alleles), nonrandom mating and genetic hitchhiking. In the early 20th century the modern evolutionary synthesis integrated classical genetics with Darwin's theory of evolution by natural selection through the discipline of population genetics. Te importance of natural selection as a cause of evolution was accepted into other branches of biology. Moreover, previously held notions about evolution, such as orthogenesis, evolutionism, and other beliefs about innate "progress" within the largest-scale trends in evolution, became obsolete. Scientists continue to study various aspects of evolutionary biology by forming and testing hypotheses, constructing mathematical models of theoretical biology and biological theories, using observational data, and performing experiments in both the feld and the laboratory.

All life on Earth shares a common ancestor known as the last universal common ancestor (LUCA), which lived approximately 3.5–3.8 billion years ago. A December 2017 report stated that 3.45 billion year old Australian rocks once contained microorganisms, the earliest direct evidence of life on Earth. Nonetheless, this should not be assumed to be the frst living organism on Earth; a study in 2015 found "remains of biotic life" from 4.1 billion years ago in ancient rocks in Western Australia. In July 2016, scientists reported identifying a set of 355 genes from the LUCA of all organisms living on Earth. More than 99 percent of all species that ever lived on Earth are estimated to be extinct. Estimates of Earth's current species range from 10 to 14 million, of which about 1.9 million are estimated to have been named and 1.6 million documented in a central database to date. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.

In terms of practical application, an understanding of evolution has been instrumental to developments in numerous scientifc and industrial felds, including agriculture, human and veterinary medicine, and the life sciences in general. Discoveries in evolutionary biology have made a signifcant impact not just in the traditional branches of biology but also in other academic disciplines, including biological anthropology, and evolutionary psychology. Evolutionary

1 8 o f 1 1 1 computation, a sub-feld of artifcial intelligence, involves the application of Darwinian principles to problems in computer science.

Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms' activities (energy transformation). Tis chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek φῶς, phōs, "light", and σύνθεσις, synthesis, "putting together". In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these 173 light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, producing oxygen gas. Te hydrogen freed by the splitting of water is used in the creation of two further compounds that serve as short-term stores of energy, enabling its transfer to drive other reactions: these compounds are reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP), the "energy currency" of cells. In plants, algae and cyanobacteria, long-term energy storage in the form of sugars is produced by a subsequent sequence of light-independent reactions called the Calvin cycle; some bacteria use different mechanisms, such as the reverse Krebs cycle, to achieve the same end. In the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate (RuBP). Using the ATP and NADPH produced by the light-dependent reactions, the resulting compounds are then reduced and removed to form further carbohydrates, such as glucose. Te frst photosynthetic organisms probably evolved early in the evolutionary history of life and most likely used reducing agents such as hydrogen or hydrogen sulfde, rather than water, as sources of electrons. Cyanobacteria appeared later; the excess oxygen they produced contributed directly to the oxygenation of the Earth, which rendered the evolution of complex life possible. Today, the average rate of energy capture by photosynthesis globally is approximately 130 terawatts, which is about three times the current power consumption of human civilization. Photosynthetic organisms also convert around 100–115 thousand million metric tonnes of carbon into biomass per year.

Most of the well-recognized phototrophs are autotrophic, also known as photoautotrophs, and can fx carbon. Tey can be contrasted with chemotrophs that obtain their energy by the oxidation of electron donors in their environments. Photoautotrophs are capable of synthesizing their own food from inorganic substances using light as an energy source. Green plants and photosynthetic bacteria are photoautotrophs. Photoautotrophic organisms are sometimes referred to as holophytic.[3] Such organisms derive their energy for food synthesis from light and are capable of using carbon dioxide as their principal source of carbon.

Oxygenic photosynthetic organisms use chlorophyll for light-energy capture and oxidize water, "splitting" it into molecular oxygen. In contrast, anoxygenic photosynthetic bacteria have a substance called bacteriochlorophyll - which absorbs predominantly at non-optical wavelengths - for light-energy capture, live in aquatic environments, and will, using light, oxidize chemical substances such as hydrogen sulfde rather than water.

In an ecological context, phototrophs are often the food source for neighboring heterotrophic life. In terrestrial environments, plants are the predominant variety, while aquatic environments include a range of phototrophic organisms such as algae (e.g., kelp), other protists (such as euglena), phytoplankton, and bacteria (such as cyanobacteria). Te depth to which sunlight or artifcial light can penetrate into water, so that photosynthesis may occur, is known as the photic zone.

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Cyanobacteria, which are prokaryotic organisms which carry out oxygenic photosynthesis, occupy many environmental conditions, including fresh water, seas, soil, and lichen. Cyanobacteria carry out plant-like photosynthesis because the organelle in plants that carries out photosynthesis is derived from an [4] endosymbiosis cyanobacterium.[5] Tis bacterium can use water as a source of electrons in order to perform CO2 reduction reactions. Evolutionarily, cyanobacteria's ability to survive in oxygenic conditions, which are considered toxic to most anaerobic bacteria, might have given the bacteria an adaptive advantage which could have allowed the cyanobacteria to populate more eﬃciently.

A photolithoautotroph is an autotrophic organism that uses light energy, and an inorganic electron donor (e.g., H2O, H2, H2S), and CO2 as its carbon source. Examples include plants.

In biology, an organism (from Greek: οργανισμός, organismos) is any individual entity that exhibits the properties of life. It is a synonym for "life form".

Organisms are classifed by taxonomy into specifed groups such as the multicellular animals, plants, and fungi; or unicellular microorganisms such as a protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Humans are multicellular animals composed of many trillions of cells which diﬀerentiate during development into specialized tissues and organs.

An organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains—bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants and plastids in plants and algae, all generally considered to be derived from endosymbiotic bacteria). Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes.

174 A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle.Te word prokaryote comes from the Greek πρό (pro) "before" and κάρυον (karyon) "nut or kernel". Prokaryotes are divided into two domains, Archaea and Bacteria. In contrast, species with nuclei and organelles are placed in the third domain, Eukaryota. Prokaryotes reproduce without fusion of gametes. Te frst living organisms are thought to have been prokaryotes.

In the prokaryotes, all the intracellular water-soluble components (proteins, DNA and metabolites) are located together in the cytoplasm enclosed by the cell membrane, rather than in separate cellular compartments. Bacteria, however, do possess protein-based bacterial microcompartments, which are thought to act as primitive organelles enclosed in protein shells. Some prokaryotes, such as cyanobacteria may form large colonies. Others, such as myxobacteria, have multicellular stages in their life cycles.

A eukaryote (/juːˈkæri.oʊt/ or /juːˈkæriət/) is any organism whose cells have a cell nucleus and other organelles enclosed within membranes. Eukaryotes belong to the domain Eukaryota or Eukarya, and can be unicellular or multicellular organisms. Te defning feature that sets eukaryotic cells apart from prokaryotic cells (Bacteria and Archaea) is that they have membrane-bound organelles, especially the nucleus, which contains the genetic material enclosed by the nuclear membrane.Te presence of a nucleus gives eukaryotes their name, which comes from the Greek εὖ (eu, "well" or "true") and κάρυον (karyon, "nut" or "kernel"). Eukaryotic cells also contain other membrane- bound organelles such as mitochondria and the Golgi apparatus. In addition, plants and algae contain chloroplasts. Unlike unicellular archaea and bacteria, eukaryotes may also be multicellular and include organisms consisting of many kinds of tissue and cell types.

Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion. In mitosis, one cell divides to produce two genetically identical cells. In meiosis, DNA replication is followed by two rounds of cell division to produce four haploid daughter cells. 2 0 o f 1 1 1

Tese act as sex cells (gametes). Each gamete has just one set of chromosomes, each a unique mix of the corresponding pair of parental chromosomes resulting from genetic recombination during meiosis.

Te domain Eukaryota appears to be monophyletic, and makes up one of the domains of life in the three-domain system. Te two other domains, Bacteria and Archaea, are prokaryotes and have none of the above features. Eukaryotes represent a tiny minority of all living things. However, due to their generally much larger size, their collective worldwide biomass is estimated to be about equal to that of prokaryotes. Eukaryotes evolved approximately 1.6–2.1 billion years ago, during the Proterozoic eon.

Molecular studies have provided insight into the evolution and interrelationships of the three domains of biological species. Eukaryotes are organisms, including humans, whose cells have a well defned membrane-bound nucleus (containing chromosomal DNA) and organelles. Te division between prokaryotes and eukaryotes refects the existence of two very diﬀerent levels of cellular organization. Distinctive types of prokaryotes include extremophiles and methanogens; these are common in some extreme environments.

Taxonomy (from Ancient Greek τάξις (taxis), meaning 'arrangement', and -νομία (-nomia), meaning 'method') is the science of defning and naming groups of biological organisms on the basis of shared characteristics. Organisms are grouped together into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super-group of higher rank, thus creating a taxonomic hierarchy. Te principal ranks in modern use are domain, kingdom, phylum (division is sometimes used in botany in place of phylum), class, order, family, genus and species. Te Swedish botanist Carl Linnaeus is regarded as the father of taxonomy, as he developed a system known as Linnaean taxonomy for categorization of organisms and binomial nomenclature for naming organisms.

With the advent of such felds of study as phylogenetics, cladistics, and systematics, the Linnaean system has progressed to a system of modern biological classifcation based on the evolutionary relationships between organisms, both living and extinct.

Estimates on the number of Earth's current species range from 10 million to 14 million, of which only about 1.2 million have been documented. More than 99% of all species, amounting to over fve billion species, that ever lived are estimated to be extinct. In 2016, a set of 355 genes from the last universal common ancestor (LUCA) of all living organisms living was identifed.

Symbiosis (from Greek συμβίωσις "living together", from σύν "together" and βίωσις "living") is any type of a close and long-term biological interaction between two diﬀerent biological organisms, be it mutualistic, commensalistic, or 175 parasitic. Te organisms may be of the same or of diﬀerent species. In 1879, Heinrich Anton de Bary defned it as "the living together of unlike organisms".

Symbiosis can be obligatory, which means that one or both of the symbionts entirely depend on each other for survival, or facultative (optional) when they can generally live independently.

Symbiosis is also classifed by physical attachment; symbiosis in which the organisms have bodily union is called conjunctive symbiosis, and symbiosis in which they are not in union is called disjunctive symbiosis. When one organism lives on another such as mistletoe, it is called ectosymbiosis, or endosymbiosis when one partner lives inside the tissues of another, as in Symbiodinium in corals.

In biology, matrix (plural: matrices) is the material (or tissue) in animal or plant cells, in which more specialized structures are embedded, and a specifc part of the mitochondrion. Te internal structure of connective tissues is an extracellular matrix. Finger nails and toenails grow from

2 1 o f 1 1 1 matrices. It is found in various connective tissue. It is generally used as a jelly like structure instead of cytoplasm in connective tissue.

In biology, phylogenetics /ˌfaɪloʊdʒəˈnɛtɪks, -lə-/ (Greek: φυλή, φῦλον - phylé, phylon = tribe, clan, race + γενετικός - genetikós = origin, source, birth) is the study of the evolutionary history and relationships among individuals or groups of organisms (e.g. species, or populations). Tese relationships are discovered through phylogenetic inference methods that evaluate observed heritable traits, such as DNA sequences or morphology under a model of evolution of these traits. Te result of these analyses is a phylogeny (also known as a phylogenetic tree) – a diagrammatic hypothesis about the history of the evolutionary relationships of a group of organisms. Te tips of a phylogenetic tree can be living organisms or fossils, and represent the "end", or the present, in an evolutionary lineage. Phylogenetic analyses have become central to understanding biodiversity, evolution, ecology, and genomes.

Taxonomy is the identifcation, naming and classifcation of organisms. It is usually richly informed by phylogenetics, but remains a methodologically and logically distinct discipline. Te degree to which taxonomies depend on phylogenies (or classifcation depends on evolutionary development) diﬀers depending on the school of taxonomy: phenetics ignores phylogeny altogether, trying to represent the similarity between organisms instead; cladistics (phylogenetic systematics) tries to reproduce phylogeny in its classifcation without loss of information; evolutionary taxonomy tries to fnd a compromise between them.

Cladistics (from Greek κλάδος, klados, i.e., "branch") is an approach to biological classifcation in which organisms are categorized based on shared derived characteristics that can be traced to a group's most recent common ancestor and are not present in more distant ancestors. Terefore, members of a group are assumed to share a common history and are considered to be closely related.

Te techniques and nomenclature of cladistics have been applied to other disciplines. (See phylogenetic nomenclature.)

Te original methods used in cladistic analysis and the school of taxonomy derived from the work of the German entomologist Willi Hennig, who referred to it as phylogenetic systematics (also the title of his 1966 book); the terms "cladistics" and "clade" were popularized by other researchers. Cladistics in the original sense refers to a particular set of methods used in phylogenetic analysis, although it is now sometimes used to refer to the whole feld.

What is now called the cladistic method appeared as early as 1901 with a work by Peter Chalmers Mitchell for birds and subsequently by Robert John Tillyard (for insects) in 1921, and W. Zimmermann (for plants) in 1943.[ Te term "clade" was introduced in 1958 by Julian Huxley after having been coined by Lucien Cuénot in 1940, "cladogenesis" in 1958, "cladistic" by Cain and Harrison in 1960, "cladist" (for an adherent of Hennig's school) by Mayr in 1965, and "cladistics" in 1966. Hennig referred to his own approach as "phylogenetic systematics". From the time of his original formulation until the end of the 1970s, cladistics competed as an analytical and philosophical approach to phylogenetic inference with phenetics and so-called evolutionary taxonomy. Phenetics was championed at this time by the numerical taxonomists Peter Sneath and Robert Sokal and the evolutionary taxonomist Ernst Mayr.

Originally conceived, if only in essence, by Willi Hennig in a book published in 1950, cladistics did not fourish until its translation into English in 1966 (Lewin 1997). Today, cladistics is the most popular method for constructing phylogenies

176 from morphological and molecular data. Unlike phenetics, cladistics is specifcally aimed at reconstructing evolutionary histories.

In the 1990s, the development of eﬀective polymerase chain reaction techniques allowed the application of cladistic methods to biochemical and molecular genetic traits of organisms, as well as to anatomical ones, vastly expanding the amount of data available for phylogenetics. At the 2 2 o f 1 1 1 same time, cladistics rapidly became the dominant set of methods of phylogenetics in evolutionary biology, because computers made it possible to process large quantities of data about organisms and their characteristics.

Te way for computational phylogenetics was paved by phenetics, a set of methods commonly used from the 1950s to 1980s and to some degree later. Phenetics did not try to reconstruct phylogenetic trees; rather, it tried to build dendrograms from similarity data; its algorithms required less computer power than phylogenetic ones.

In biology, phenetics (Greek: phainein - to appear) /fɪˈnɛtɪks/, also known as taximetrics, is an attempt to classify organisms based on overall similarity, usually in morphology or other observable traits, regardless of their phylogeny or evolutionary relation. It is closely related to numerical taxonomy which is concerned with the use of numerical methods for taxonomic classifcation. Many people contributed to the development of phenetics, but the most infuential were Peter Sneath and Robert R. Sokal. Teir books are still primary references for this sub-discipline, although now out of print.

Phenetics has largely been superseded by cladistics for research into evolutionary relationships among species. However, certain phenetic methods, such as neighbor-joining, have found their way into phylogenetics, as a reasonable approximation of phylogeny when more advanced methods (such as Bayesian inference) are too computationally expensive.

Phenetic techniques include various forms of clustering and ordination. Tese are sophisticated ways of reducing the variation displayed by organisms to a manageable level. In practice this means measuring dozens of variables, and then presenting them as two- or three-dimensional graphs. Much of the technical challenge in phenetics revolves around balancing the loss of information in such a reduction against the ease of interpreting the resulting graphs.

Te method can be traced back to 1763 and Michel Adanson (in his Familles des plantes) because of two shared basic principles — overall similarity and equal weighting — and modern pheneticists are sometimes called neo-Adansonians.

Biological systematics is the study of the diversifcation of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic trees, phylogenies). Phylogenies have two components: branching order (showing group relationships) and branch length (showing amount of evolution). Phylogenetic trees of species and higher taxa are used to study the evolution of traits (e.g., anatomical or molecular characteristics) and the distribution of organisms (biogeography). Systematics, in other words, is used to understand the evolutionary history of life on Earth.

Mutualism is the way two organisms of diﬀerent species exist in a relationship in which each individual benefts from the activity of the other. Similar interactions within a species are known as co-operation. Mutualism can be contrasted with interspecifc competition, in which each species experiences reduced ftness, and exploitation, or parasitism, in which one species benefts at the "expense" of the other. Symbiosis involves two species living in close proximity and includes relationships that are mutualistic, parasitic, and commensal. Symbiotic relationships are sometimes, but not always, mutualistic.

A well-known mutualism is the relationship between ungulates (such as bovines) and bacteria within their intestines. Te ungulates beneft from the cellulase produced by the bacteria, which facilitates digestion; the bacteria beneft from having a stable supply of nutrients in the host environment. Tis can also be found in many many diﬀerent symbiotic relationships.

Mutualism plays a key part in ecology. For example, mutualistic interactions are vital for terrestrial ecosystem function as more than 48% of land plants rely on mycorrhizal relationships with fungi to provide them with inorganic compounds and trace elements. In addition, mutualism is thought to 2 3 o f 1 1 1 have driven the evolution of much of the biological diversity we see, such as fower forms (important for pollination mutualisms) and co-evolution between groups of species. However mutualism has historically received less attention than other interactions such as predation and parasitism.

177 Measuring the exact ftness beneft to the individuals in a mutualistic relationship is not always straightforward, particularly when the individuals can receive benefts from a variety of species, for example most plant-pollinator mutualisms. It is therefore common to categorise mutualisms according to the closeness of the association, using terms such as obligate and facultative. Defning "closeness," however, is also problematic. It can refer to mutual dependency (the species cannot live without one another) or the biological intimacy of the relationship in relation to physical closeness (e.g., one species living within the tissues of the other species).

In biology, parasitism is a non-mutual relationship between species, where one species, the parasite, benefts at the expense of the other, the host. Traditionally parasite primarily meant an organism visible to the naked eye, or a macroparasite (such as a helminth). Microparasites are typically far smaller, such as protozoa, viruses, and bacteria. Examples of parasites include the plants mistletoe and cuscuta, and animals such as hookworms.

Unlike predators, parasites typically do not kill their host, are generally much smaller than their host, and often live in or on their host for an extended period. Both are special cases of consumer- resource interactions. Parasites of animals show a high degree of specialization, and reproduce at a faster rate than their hosts. Classic examples include interactions between vertebrate hosts and tapeworms, fukes, the Plasmodium species, and feas. Parasitoidy is an evolutionary strategy within parasitism in which the parasite eventually kills its host.

Parasites reduce host biological ftness by general or specialized pathology, from parasitic castration and impairment of secondary sex characteristics, to the modifcation of host behavior. Parasites increase their own ftness by exploiting hosts for resources necessary for their survival, in particular transmission. Although parasitism often applies unambiguously, it is part of a continuum of types of interactions between species, grading via parasitoidy into predation, through evolution into mutualism, and in some fungi, shading into being saprophytic.

People have known about parasites such as roundworms and tapeworms since ancient Egypt, Greece, and Rome. In Early Modern times, Antonie van Leeuwenhoek observed Giardia lamblia in his microscope in 1681, while Francesco Redi described endo- and ectoparasites including sheep liver fuke and ticks. Modern parasitology developed in the 19th century. In human culture, parasitism has negative connotations. Tese were exploited to satirical eﬀect in Jonathan Swift's 1733 poem "On Poetry: A Rhapsody", comparing poets to hyperparasitical "vermin". In fction, Bram Stoker's 1897 Gothic horror novel Dracula and its many later adaptations featured a blood- drinking parasite. Ridley Scott's 1979 flm Alien was one of many works of science fction to feature a terrifying parasitic alien species.

In biology and ecology, extinction is the termination of an organism or of a group of organisms (taxon), normally a species. Te moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is diﬃcult, and is usually done retrospectively. Tis diﬃculty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence.

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Chemistry

178 Chemistry is the scientifc discipline involved with compounds composed of atoms, i.e. elements, and molecules, i.e. combinations of atoms: their composition, structure, properties, behavior and the changes they undergo during a reaction with other compounds. Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. Tere are four types of chemical bonds: covalent bonds, in which compounds share one or more electron(s); ionic bonds, in which a compound donates one or more electrons to another compound to produce ions: cations and anions; hydrogen bonds; and Van der Waals force bonds. See glossary of chemistry.

In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientifc disciplines at a fundamental level.[4] Examples include plant chemistry (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the moon (astrophysics), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics).

Te history of chemistry spans a period from very old times to the present. Since several millennia BC, civilizations were using technologies that would eventually form the basis of the various branches of chemistry. Examples include extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering

2 5 o f 1 1 1 fat into soap, making glass, and making alloys like bronze. Chemistry was preceded by its protoscience, alchemy, which is an intuitive but non-scientifc approach to understanding the constituents of matter and their interactions. It was unsuccessful in explaining the nature of matter and its transformations, but, by performing experiments and recording the results, alchemists set the stage for modern chemistry.

Chemical structure refers to both molecular geometry and electronic structure. Te structure can be represented by a variety of diagrams called structural formulas. Lewis structures use a dot notation to represent the valence electrons for an atom; these are the electrons that determine the role of the atom in chemical reactions.:71–72 Bonds between atoms can be represented by lines with one line for each pair of electrons that is shared. In a simplifed version of such a diagram, called a skeletal formula, only carbon-carbon bonds and functional groups are shown.

Atoms in a crystal have a structure that involves repetition of a basic unit called a unit cell. Te atoms can be modeled as points on a lattice, and one can explore the eﬀect of symmetry operations that include rotations about a point, refections about a symmetry planes, and translations (movements of all the points by the same amount). Each crystal has a fnite group, called the space group, of such operations that map it onto itself; there are 230 possible space groups. By Neumann's law, the symmetry of a crystal determines what physical properties, including piezoelectricity and ferromagnetism, the crystal can have.

A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity. Simply speaking, chemical properties cannot be determined just by viewing or touching the substance; the substance's internal structure must be aﬀected greatly for its chemical properties to be investigated. When a substance goes under a chemical reaction, the properties will change drastically, resulting in chemical change. However, a catalytic property would also be a chemical property.

Chemical properties can be contrasted with physical properties, which can be discerned without changing the substance's structure. However, for many properties within the scope of physical chemistry, and other disciplines at the boundary between chemistry and physics, the distinction may be a matter of researcher's perspective. Material properties, both physical and chemical, can be viewed as supervenient; i.e., secondary to the underlying reality. Several layers of superveniency are possible.

Chemical properties can be used for building chemical classifcations. Tey can also be useful to identify an unknown substance or to separate or purify it from other substances. Materials science will normally consider the chemical properties of a substance to guide its applications.

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

179 Te substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties diﬀerent from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise course of action is part of the reaction mechanism. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.

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Chemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration. Typically, reaction rates increase with increasing temperature because there is more thermal energy available to reach the activation energy necessary for breaking bonds between atoms.

Reactions may proceed in the forward or reverse direction until they go to completion or reach equilibrium. Reactions that proceed in the forward direction to approach equilibrium are often described as spontaneous, requiring no input of free energy to go forward. Non-spontaneous reactions require input of free energy to go forward (examples include charging a battery by applying an external electrical power source, or photosynthesis driven by absorption of electromagnetic radiation in the form of sunlight).

Diﬀerent chemical reactions are used in combinations during chemical synthesis in order to obtain a desired product. In biochemistry, a consecutive series of chemical reactions (where the product of one reaction is the reactant of the next reaction) form metabolic pathways. Tese reactions are often catalyzed by protein enzymes. Enzymes increase the rates of biochemical reactions, so that metabolic syntheses and decompositions impossible under ordinary conditions can occur at the temperatures and concentrations present within a cell.

Te general concept of a chemical reaction has been extended to reactions between entities smaller than atoms, including nuclear reactions, radioactive decays, and reactions between elementary particles as described by quantum feld theory.

A chemical element is a species of atoms having the same number of protons in their atomic nuclei (that is, the same atomic number, or Z).118 elements are identifed, of which the frst 94 occur naturally on Earth with the remaining 24 being synthetic elements. Tere are 80 elements that have at least one stable isotope and 38 that have exclusively radionuclides, which decay over time into other elements. Iron is the most abundant element (by mass) making up Earth, while oxygen is the most common element in the Earth's crust.

Chemical elements constitute all of the ordinary matter of the universe. However astronomical observations suggest that ordinary observable matter makes up only about 15% of the matter in the universe: the remainder is dark matter; the composition of this is unknown, but it is not composed of chemical elements. Te two lightest elements, hydrogen and helium, were mostly formed in the Big Bang and are the most common elements in the universe. Te next three elements (lithium, beryllium and boron) were formed mostly by cosmic ray spallation, and are thus rarer than heavier elements. Formation of elements with from 6 to 26 protons occurred and continues to occur in main sequence stars via stellar nucleosynthesis. Te high abundance of oxygen, silicon, and iron on Earth refects their common production in such stars. Elements with greater than 26 protons are formed by supernova nucleosynthesis in supernovae, which, when they explode, blast these elements as supernova remnants far into space, where they may become incorporated into planets when they are formed.

Te term "element" is used for atoms with a given number of protons (regardless of whether or not they are ionized or chemically bonded, e.g. hydrogen in water) as well as for a pure chemical substance consisting of a single element (e.g. hydrogen gas). For the second meaning, the terms "elementary substance" and "simple substance" have been suggested, but they have not gained much acceptance in English chemical literature, whereas in some other languages their equivalent is widely used (e.g. French corps simple, Russian простое вещество). A single element can form multiple substances diﬀering in their structure; they are called allotropes of the element.

When diﬀerent elements are chemically combined, with the atoms held together by chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals. Among the more common of such native elements are copper, silver, gold, 2 7 o f 1 1 1 carbon (as coal, graphite, or diamonds), and sulfur. All but a few of the most inert elements, such as noble gases and noble metals, are usually found on Earth in chemically combined form, as chemical compounds. While about 32 of the chemical elements occur on Earth in native uncombined forms, most of these occur as mixtures. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, and native solid elements occur in alloys, such as that of iron and nickel. 180 Te history of the discovery and use of the elements began with primitive human societies that found native elements like carbon, sulfur, copper and gold. Later civilizations extracted elemental copper, tin, lead and iron from their ores by smelting, using charcoal. Alchemists and chemists subsequently identifed many more; almost all of the naturally occurring elements were known by 1900.

Te properties of the chemical elements are summarized in the periodic table, which organizes the elements by increasing atomic number into rows ("periods") in which the columns ("groups") share recurring ("periodic") physical and chemical properties. Save for unstable radioactive elements with short half-lives, all of the elements are available industrially, most of them in low degrees of impurities.

Periods A period is a horizontal row in the periodic table. Although groups generally have more signifcant periodic trends, there are regions where horizontal trends are more signifcant than vertical group trends, such as the f-block, where the lanthanides and actinides form two substantial horizontal series of elements.

Elements in the same period show trends in atomic radius, ionization energy, electron affinity, and electronegativity. Moving left to right across a period, atomic radius usually decreases. Tis occurs because each successive element has an added proton and electron, which causes the electron to be drawn closer to the nucleus. Tis decrease in atomic radius also causes the ionization energy to increase when moving from left to right across a period. Te more tightly bound an element is, the more energy is required to remove an electron. Electronegativity increases in the same manner as ionization energy because of the pull exerted on the electrons by the nucleus.[18] Electron affinity also shows a slight trend across a period. Metals (left side of a period) generally have a lower electron affinity than nonmetals (right side of a period), with the exception of the noble gases.

Blocks: Specifc regions of the periodic table can be referred to as blocks in recognition of the sequence in which the electron shells of the elements are flled. Each block is named according to the subshell in which the "last" electron notionally resides. Te s-block comprises the frst two groups (alkali metals and alkaline earth metals) as well as hydrogen and helium. Te p- block comprises the last six groups, which are groups 13 to 18 in IUPAC group numbering (3A to 8A in American group numbering) and contains, among other elements, all of the metalloids. Te d-block comprises groups 3 to 12 (or 3B to 2B in American group numbering) and contains all of the transition metals. Te f-block, often oﬀset below the rest of the periodic table, has no group numbers and comprises lanthanides and actinides.

Metals, metalloids and nonmetals

Metals, metalloids, nonmetals, and elements with unknown chemical properties in the periodic table. Sources disagree on the classifcation of some of these elements. According to their shared physical and chemical properties, the elements can be classifed into the major categories of metals, metalloids and nonmetals. Metals are generally shiny, highly conducting solids that form alloys with one another and salt- like ionic compounds with nonmetals (other than the noble gases). Te majority of nonmetals are coloured or colourless insulating gases; nonmetals that form compounds with other nonmetals feature covalent bonding. In between metals and nonmetals are metalloids, which have intermediate or mixed properties.

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Metal and nonmetals can be further classifed into subcategories that show a gradation from metallic to non-metallic properties, when going left to right in the rows. Te metals are subdivided into the highly reactive alkali metals, through the less reactive alkaline earth metals, lanthanides and actinides, via the archetypal transition metals, and ending in the physically and chemically weak post-transition metals. Te nonmetals are simply subdivided into the polyatomic nonmetals, which, being nearest to the metalloids, show some incipient metallic character; the diatomic nonmetals, which are essentially nonmetallic; and the monatomic noble gases, which are nonmetallic and almost completely inert. Specialized groupings such as the refractory metals and the noble metals, which are subsets (in this example) of the transition metals, are also known and occasionally denoted.

Placing the elements into categories and subcategories based on shared properties is imperfect. Tere is a spectrum of properties within each category and it is not hard to fnd overlaps at the boundaries, as is the case with most classifcation schemes. Beryllium, for example, is classifed as an alkaline earth metal although its amphoteric chemistry and tendency to mostly form covalent compounds are both attributes of a chemically weak or post-transition metal. Radon is classifed as a nonmetal and a noble gas yet has some cationic chemistry that is more characteristic of a metal. Other classifcation schemes are possible such as the division of the elements into mineralogical occurrence categories, or crystalline structures. Categorizing the elements in this fashion dates back to at least 1869 when Hinrichs wrote that simple boundary lines could

181 be drawn on the periodic table to show elements having like properties, such as the metals and the nonmetals, or the gaseous elements.

Te electron confguration or organisation of electrons orbiting neutral atoms shows a recurring pattern or periodicity. Te electrons occupy a series of electron shells (numbered 1, 2, and so on). Each shell consists of one or more subshells (named s, p, d, f and g). As atomic number increases, electrons progressively fll these shells and subshells more or less according to the Madelung rule or energy ordering rule, as shown in the diagram. Te electron confguration for neon, for example, is 1s2 2s2 2p6. With an atomic number of ten, neon has two electrons in the frst shell, and eight electrons in the second shell; there are two electrons in the s subshell and six in the p subshell. In periodic table terms, the frst time an electron occupies a new shell corresponds to the start of each new period, these positions being occupied by hydrogen and the alkali metals.

Periodic table trends (arrows show an increase) Since the properties of an element are mostly determined by its electron confguration, the properties of the elements likewise show recurring patterns or periodic behaviour, some examples of which are shown in the diagrams below for atomic radii, ionization energy and electron aﬃnity. It is this periodicity of properties, manifestations of which were noticed well before the underlying theory was developed, that led to the establishment of the periodic law (the properties of the elements recur at varying intervals) and the formulation of the frst periodic tables.

Atomic radii: Atomic number plotted against atomic radius Atomic radii vary in a predictable and explainable manner across the periodic table. For instance, the radii generally decrease along each period of the table, from the alkali metals to the noble gases; and increase down each group. Te radius increases sharply between the noble gas at the end of each period and the alkali metal at the beginning of the next period. Tese trends of the atomic radii (and of various other chemical and physical properties of the elements) can be explained by the electron shell theory of the atom; they provided important evidence for the development and confrmation of quantum theory.

Te electrons in the 4f-subshell, which is progressively flled from cerium (element 58) to ytterbium (element 70), are not particularly effective at shielding the increasing nuclear charge from the subshells further out. Te elements immediately following the lanthanides have atomic radii that are smaller than would be expected and that are almost identical to the atomic radii of the elements immediately above them. Hence hafnium has virtually the same atomic radius (and chemistry) as zirconium, and tantalum has an atomic radius similar to niobium, and so forth. Tis is known as the 2 9 o f 1 1 1 lanthanide contraction. Te effect of the lanthanide contraction is noticeable up to platinum (element 78), after which it is masked by a relativistic effect known as the inert pair effect. Te d- block contraction, which is a similar effect between the d-block and p-block, is less pronounced than the lanthanide contraction but arises from a similar cause.

Ionization energy

Ionization energy: each period begins at a minimum for the alkali metals, and ends at a maximum for the noble gases Te frst ionization energy is the energy it takes to remove one electron from an atom, the second ionization energy is the energy it takes to remove a second electron from the atom, and so on. For a given atom, successive ionization energies increase with the degree of ionization. For magnesium as an example, the frst ionization energy is 738 kJ/mol and the second is 1450 kJ/ mol. Electrons in the closer orbitals experience greater forces of electrostatic attraction; thus, their removal requires increasingly more energy. Ionization energy becomes greater up and to the right of the periodic table.

Large jumps in the successive molar ionization energies occur when removing an electron from a noble gas (complete electron shell) confguration. For magnesium again, the frst two molar ionization energies of magnesium given above correspond to removing the two 3s electrons, and the third ionization energy is a much larger 7730 kJ/mol, for the removal of a 2p electron from the very stable neon-like confguration of Mg2+. Similar jumps occur in the ionization energies of other third-row atoms.

Electronegativity: Graph showing increasing electronegativity with growing number of selected groups Electronegativity is the tendency of an atom to attract electrons. An atom's electronegativity is aﬀected by both its atomic number and the distance between the valence electrons and the nucleus. Te higher its electronegativity, the more an element attracts electrons. It was frst proposed by Linus Pauling in 1932. In general, electronegativity increases on passing from left to right along a period, and decreases on descending a group. Hence, fuorine is the most electronegative of the elements,[n 5] while caesium is the least, at least of those elements for which substantial data is available.

Tere are some exceptions to this general rule. Gallium and germanium have higher electronegativities than aluminium and silicon respectively because of the d-block contraction. Elements of the fourth period immediately after the frst row of the transition metals have unusually small atomic radii because the 3d-electrons are not eﬀective at shielding the increased

182 nuclear charge, and smaller atomic size correlates with higher electronegativity. Te anomalously high electronegativity of lead, particularly when compared to thallium and bismuth, appears to be an artifact of data selection and data availability. Methods of calculation other than the Pauling method show the normal periodic trends for these elements.

Dependence of electron aﬃnity on atomic number. Values generally increase across each period, culminating with the halogens before decreasing precipitously with the noble gases. Examples of localized peaks seen in hydrogen, the alkali metals and the group 11 elements are caused by a tendency to complete the s-shell (with the 6s shell of gold being further stabilized by relativistic eﬀects and the presence of a flled 4f sub shell). Examples of localized troughs seen in the alkaline earth metals, and nitrogen, phosphorus, manganese and rhenium are caused by flled s-shells, or half-flled p- or d-shells.

Te electron affinity of an atom is the amount of energy released when an electron is added to a neutral atom to form a negative ion. Although electron affinity varies greatly, some patterns emerge. Generally, nonmetals have more positive electron affinity values than metals. Chlorine most strongly attracts an extra electron. Te electron affinities of the noble gases have not been measured conclusively, so they may or may not have slightly negative values.

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Electron aﬃnity generally increases across a period. Tis is caused by the flling of the valence shell of the atom; a group 17 atom releases more energy than a group 1 atom on gaining an electron because it obtains a flled valence shell and is therefore more stable.

A trend of decreasing electron affinity going down groups would be expected. Te additional electron will be entering an orbital farther away from the nucleus. As such this electron would be less attracted to the nucleus and would release less energy when added. In going down a group, around one-third of elements are anomalous, with heavier elements having higher electron affinities than their next lighter congenors. Largely, this is due to the poor shielding by d and f electrons. A uniform decrease in electron affinity only applies to group 1 atoms.

Te lower the values of ionization energy, electronegativity and electron aﬃnity, the more metallic character the element has. Conversely, nonmetallic character increases with higher values of these properties. Given the periodic trends of these three properties, metallic character tends to decrease going across a period (or row) and, with some irregularities (mostly) due to poor screening of the nucleus by d and f electrons, and relativistic eﬀects, tends to increase going down a group (or column or family). Tus, the most metallic elements (such as caesium and francium) are found at the bottom left of traditional periodic tables and the most nonmetallic elements (oxygen, fuorine, chlorine) at the top right. Te combination of horizontal and vertical trends in metallic character explains the stair-shaped dividing line between metals and nonmetals found on some periodic tables, and the practice of sometimes categorizing several elements adjacent to that line, or elements adjacent to those elements, as metalloids.

Catalysis (/kəˈtælɪsɪs/) is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst (/ˈkætəlɪst/), which is not consumed in the catalyzed reaction and can continue to act repeatedly. Often only tiny amounts of catalyst are required in principle.

In general, reactions occur faster with a catalyst because they require less activation energy. In catalyzed mechanisms, the catalyst usually reacts to form a temporary intermediate which then regenerates the original catalyst in a cyclic process.

Catalysts may be classifed as either homogeneous or heterogeneous. A homogeneous catalyst is one whose molecules are dispersed in the same phase (usually gaseous or liquid) as the reactant molecules. A heterogeneous catalyst is one whose molecules are not in the same phase as the reactants, which are typically gases or liquids that are adsorbed onto the surface of the solid catalyst. Enzymes and other biocatalysts are often considered as a third category.

Diﬀusion is the net movement of molecules or atoms from a region of high concentration with high chemical potential to a region of low concentration with low chemical potential. Tis is also referred to as the movement of a substance down a concentration gradient.

A gradient is the change in the value of a quantity e.g. concentration, pressure, or temperature with the change in another variable, usually distance. A change in concentration over a distance is called a concentration gradient, a change in pressure over a distance is called a pressure gradient, and a change in temperature over a distance is a called a temperature gradient.

Te word diffusion derives from the Latin word, diffundere, which means "to spread way out". A substance that “spreads out” is moving from an area of high concentration to an area of low concentration. 183 A distinguishing feature of diffusion is that it depends on particle random walk, and results in mixing or mass transport without requiring directed bulk motion. Bulk motion, or bulk fow, is the

3 1 o f 1 1 1 characteristic of advection. Te term convection is used to describe the combination of both transport phenomena.

Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of diﬀerent concentrations. Osmosis can be made to do work.

Osmotic pressure is defned as the external pressure required to be applied so that there is no net movement of solvent across the membrane. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity.

Osmosis is a vital process in biological systems, as biological membranes are semipermeable. In general, these membranes are impermeable to large and polar molecules, such as ions, proteins, and polysaccharides, while being permeable to non-polar or hydrophobic molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, and nitric oxide. Permeability depends on solubility, charge, or chemistry, as well as solute size. Water molecules travel through the plasma membrane, tonoplast membrane (vacuole) or protoplast by diﬀusing across the phospholipid bilayer via aquaporins (small transmembrane proteins similar to those responsible for facilitated diﬀusion and ion channels). Osmosis provides the primary means by which water is transported into and out of cells. Te turgor pressure of a cell is largely maintained by osmosis across the cell membrane between the cell interior and its relatively hypotonic environment

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184 Physics

Physics (from Ancient Greek: φυσική (ἐπιστήμη), translit. physikḗ (epistḗmē), lit. 'knowledge of nature', from φύσις phýsis "nature") is the natural science that involves the study of matter and its motion and behavior through space and time, along with related concepts such as energy and force. One of the most fundamental scientifc disciplines, the main goal of physics is to understand how the universe `o not require a medium. Instead, they consist of periodic oscillations of electrical and magnetic felds originally generated by charged particles, and can therefore travel through a vacuum. Tese types vary in wavelength, and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.

12 point reality-

1- quaremaenganeraneumerani - 4mnxuneraengaremuna x 9 eaumernganemerangurenimunirema (per celestial body) 2 - quanernmeriumerinoguni - like particles at the end of rmiunerunengnei 3 - 3m(n)5√nxnyurneamrux3m5nux rmiunerunengnei silion per pion 4- 42 pions(quarks) per (atom) (2,000,000 nanometres per atom) jump, leap, stretch, squord and expand 5- 12 atoms per particle (purengar) 6- 14 particles per molecule 7- 400 molecules per anom 8- 5000 anoms per puma 9-1 numran is 4,000,000 puma 10 -1 murana is 40,000,000 numran 11 -1 rumean is 400,000,000 murana 12- there are 40,000,000,000,000 rumean per human body

Tere are 47 types of charges too a anonme, a photon is one of them with a darkness, a neutron is one with a lumen, electron is a glow. Tey have 7 forms of appearance amd 4 means of movement and 2 others- form and function, logistic and reason, the appearences are type, being, feeling, look, weight, sense, arythma. Te 4 movements are, Jump, Leap, Surf and Stretch. Te 1 other is scale.

In the physical sciences, a particle (or corpuscule in older texts) is a small localized object to which can be ascribed several physical or chemical properties such as volume or mass.[1][2] Tey vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientifc models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion.

Te term 'particle' is rather general in meaning, and is refned as needed by various scientifc felds. Something that is composed of particles may be referred to as being particulate.[3] However, the noun 'particulate' is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation.

A physical property is any property that is measurable, whose value describes a state of a physical system. Te changes in the physical properties of a system can be used to describe its transformations or evolutions between its momentary states. Physical properties are often referred to as observables. Tey are not modal properties. Quantifable physical property is called physical quantity.

Physical properties are often characterized as intensive and extensive properties. An intensive property does not depend on the size or extent of the system, nor on the amount of matter in the object, while an extensive property shows an additive relationship. Tese classifcations are in general only valid in cases when smaller subdivisions of the sample do not interact in some physical or chemical process when combined.

Properties may also be classifed with respect to the directionality of their nature. For example, isotropic properties do not change with the direction of observation, and anisotropic properties do have spatial variance.

It may be diﬃcult to determine whether a given property is a material property or not. Color, for example, can be seen and measured; however, what one perceives as color is really an interpretation of the refective properties of a surface and the light used to illuminate it. In this sense, many ostensibly physical properties are called supervenient. A supervenient property is one which is actual, but is secondary to some underlying reality. Tis is similar to the way in which

3 3 o f 1 1 1 185 objects are supervenient on atomic structure. A cup might have the physical properties of mass, shape, color, temperature, etc., but these properties are supervenient on the underlying atomic structure, which may in turn be supervenient on an underlying quantum structure.

Physical properties are contrasted with chemical properties which determine the way a material behaves in a chemical reaction.

In physics, the observer effect is the fact that simply observing a situation or phenomenon necessarily changes that phenomenon. Tis is often the result of instruments that, by necessity, alter the state of what they measure in some manner. A commonplace example is checking the pressure in an automobile tire; this is difficult to do without letting out some of the air, thus changing the pressure. Similarly, it is not possible to see any object without light hitting the object, and causing it to refect that light. While the effects of observation are sometimes negligible, the object still experiences a change. Tis effect can be observed in many domains of physics, but can sometimes be reduced to insignifcance by using different instruments or observation techniques.

An especially unusual version of the observer eﬀect occurs in quantum mechanics, as best demonstrated by the double-slit experiment. Physicists have found that even passive observation of quantum phenomena (by changing the test apparatus and passively 'ruling out' all but one possibility), can actually change the measured result; the 1998 Weizmann experiment is a particularly famous example. Tese fndings have led to a popular misconception that observation by a conscious mind can directly aﬀect reality, though this has been rejected by mainstream science. Tis misconception is rooted in a poor understanding of the quantum wave function ψ and the quantum measurement process.

Waves are described by a wave equation which sets out how the disturbance proceeds over time. Te mathematical form of this equation varies depending on the type of wave. Further, the behavior of particles in quantum mechanics are described by waves. In addition, gravitational waves also travel through space, which are a result of a vibration or movement in gravitational felds.

A wave can be transverse, where a disturbance creates oscillations that are perpendicular to the propagation of energy transfer, or longitudinal: the oscillations are parallel to the direction of energy propagation. While mechanical waves can be both transverse and longitudinal, all electromagnetic waves are transverse in free space.

Plasma (from Ancient Greek πλάσμα, meaning "moldable substance") is one of the four fundamental states of matter, and was frst described by chemist Irving Langmuir in the 1920s. Unlike the other three states, solid, liquid, and gas, plasma does not exist freely on the Earth's surface under normal conditions, and can only be artifcially generated by heating or subjecting a neutral gas to a strong electromagnetic feld to the point an ionised gaseous substance becomes increasingly electrically conductive, and long-range electromagnetic felds dominate the behavior of the matter.

Plasma and ionised gases have unique properties and display behaviors unlike those of the other states, and the transition between them is mostly a matter of nomenclature and subject to interpretation. Based on the surrounding environmental temperature and density, partially ionised or fully ionised forms of plasma may be produced. Neon signs or lightning storms are examples of partially ionised plasma, while the interior of the Sun is an example of fully ionised plasma, along with the solar corona and stars.

Te positive charge in ions is achieved by stripping away electrons from atomic nuclei. Te number of electrons removed is related to either the increase in temperature or the local density of other ionised matter. Tis also can be accompanied by the dissociation of molecular bonds, though this process is distinctly diﬀerent from chemical processes of ion interactions in liquids or the behavior of shared ions in metals. Te response of plasma to electromagnetic felds can be usefully employed in many modern technological devices, such as plasma televisions or plasma etching.

Plasma may be one of the most abundant form of ordinary matter in the universe, although this hypothesis is currently tentative based on the existence, the void; with 40% properties of dark matter. Plasma light frequencies is mostly associated with stars, extending to the rarefeld intracluster medium and possibly the intergalactic regions and everywhere in the zodiac.

Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). In solids molecules are closely packed. It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not fow to take on the shape of its 3 4 o f 1 1 1 container, nor does it expand to fll the entire volume available to it like a gas does. Te atoms in a solid are tightly bound to each other, either in a regular geometric lattice (crystalline solids, which include metals and ordinary ice) or irregularly (an

186 amorphous solid such as common window glass). Solids cannot compressed with little pressure whereas gases can be compressed with little pressure because in gases molecules are loosely packed.

In physics, mass–energy equivalence states that anything having mass has an equivalent amount of energy and vice versa, with these fundamental quantities directly relating to one another by Albert Einstein's famous formula:

E=mc^{2} Tis formula states that the equivalent energy (E) can be calculated as the mass (m) multiplied by the speed of light (c = about 3×108 m/s) squared. Similarly, anything having energy exhibits a corresponding mass m given by its energy E divided by the speed of light squared c2. Because the speed of light is a very large number in everyday units, the formula implies that even an everyday object at rest with a modest amount of mass has a very large amount of energy intrinsically. Chemical, nuclear, and other energy transformations may cause a system to lose some of its energy content (and thus some corresponding mass), releasing it as the radiant energy of light or as thermal energy for example.

Mass–energy equivalence arose originally from special relativity as a paradox described by Henri Poincaré. Einstein proposed it on 21 November 1905, in the paper Does the inertia of a body depend upon its energy-content?, one of his Annus Mirabilis (Miraculous Year) papers.[3] Einstein was the frst to propose that the equivalence of mass and energy is a general principle and a consequence of the symmetries of space and time.

A consequence of the mass–energy equivalence is that if a body is stationary, it still has some internal or intrinsic energy, called its rest energy, corresponding to its rest mass. When the body is in motion, its total energy is greater than its rest energy, and, equivalently, its total mass (also called relativistic mass in this context) is greater than its rest mass. Tis rest mass is also called the intrinsic or invariant mass because it remains the same regardless of this motion, even for the extreme speeds or gravity considered in special and general relativity.

Te mass-energy formula also serves to convert units of mass to units of energy (and vice versa), no matter what system of measurement units is used.

General relativity (GR, also known as the general theory of relativity or GTR) is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. General relativity has been described as the most beautiful of all existing physical theories. General relativity generalizes special relativity and Newton's law of universal gravitation, providing a unifed description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. Te relation is specifed by the Einstein feld equations, a system of partial diﬀerential equations.

Some predictions of general relativity diﬀer signifcantly from those of classical physics, especially concerning the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light. Examples of such diﬀerences include gravitational time dilation, gravitational lensing, the gravitational redshift of light, and the gravitational time delay. Te predictions of general relativity have been confrmed in all observations and experiments to date. Although general relativity is not the only relativistic theory of gravity, it is the simplest theory that is

3 5 o f 1 1 1 consistent with experimental data. However, unanswered questions remain, the most fundamental being how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity.

A gravitational singularity or spacetime singularity is a location in spacetime where the gravitational feld of a celestial body becomes infnite in a way that does not depend on the coordinate system. Te quantities used to measure gravitational feld strength are the scalar invariant curvatures of spacetime, which includes a measure of the density of matter. Since such quantities become infnite within the singularity, the laws of normal spacetime cannot exist.

Gravitational singularities are mainly considered within general relativity, where density apparently becomes infnite at the center of a black hole, and within astrophysics and cosmology as the earliest state of the universe during the Big Bang. Physicists are undecided whether the prediction of singularities means that they actually exist (or existed at the start of the Big Bang), or that current knowledge is insuﬃcient to describe what happens at such extreme densities.

187 General relativity predicts that any object collapsing beyond a certain point (for stars this is the Schwarzschild radius) would form a black hole, inside which a singularity (covered by an event horizon) would be formed. Te Penrose–Hawking singularity theorems defne a singularity to have geodesics that cannot be extended in a smooth manner. Te termination of such a geodesic is considered to be the singularity.

Te initial state of the universe, at the beginning of the Big Bang, is also predicted by modern theories to have been a singularity. In this case the universe did not collapse into a black hole, because currently-known calculations and density limits for gravitational collapse are usually based upon objects of relatively constant size, such as stars, and do not necessarily apply in the same way to rapidly expanding space such as the Big Bang. Neither general relativity nor quantum mechanics can currently describe the earliest moments of the Big Bang, but in general, quantum mechanics does not permit particles to inhabit a space smaller than their wavelengths.

Einstein's theory has important astrophysical implications. For example, it implies the existence of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape—as an end-state for massive stars. Tere is ample evidence that the intense radiation emitted by certain kinds of astronomical objects is due to black holes; for example, microquasars and active galactic nuclei result from the presence of stellar black holes and supermassive black holes, respectively. Te bending of light by gravity can lead to the phenomenon of gravitational lensing, in which multiple images of the same distant astronomical object are visible in the sky. General relativity also predicts the existence of gravitational waves, which have since been observed directly by physics collaboration LIGO. In addition, general relativity is the basis of current cosmological models of a consistently expanding universe.

Inertia is the resistance of any physical object to any change in its state of motion. Tis includes changes to the object's speed, direction, or state of rest.

Inertia is also defned as the tendency of objects to keep moving in a straight line at a constant velocity. Te principle of inertia is one of the fundamental principles in classical physics that are still used to describe the motion of objects and how they are aﬀected by the applied forces on them.

Inertia comes from the Latin word, iners, meaning idle, sluggish. Inertia is one of the primary manifestations of mass, which is a quantitative property of physical systems. Isaac Newton defned inertia as his frst law in his Philosophiæ Naturalis Principia Mathematica, which states:

Te vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.

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In common usage, the term "inertia" may refer to an object's "amount of resistance to change in velocity" (which is quantifed by its mass), or sometimes to its momentum, depending on the context. Te term "inertia" is more properly understood as shorthand for "the principle of inertia" as described by Newton in his First Law of Motion: an object not subject to any net external force moves at a constant velocity. Tus, an object will continue moving at its current velocity until some force causes its speed or direction to change.

On the surface of the Earth, inertia is often masked by the eﬀects of friction and air resistance, both of which tend to decrease the speed of moving objects (commonly to the point of rest), and gravity. Tis misled the philosopher Aristotle to believe that objects would move only as long as force was applied to them:

...it [body] stops when the force which is pushing the travelling object has no longer power to push it along...

Albert Einstein's theory of special relativity, as proposed in his 1905 paper entitled "On the Electrodynamics of Moving Bodies" was built on the understanding of inertia and inertial reference frames developed by Galileo and Newton. While this revolutionary theory did signifcantly change the meaning of many Newtonian concepts such as mass, energy, and distance, Einstein's concept of inertia remained unchanged from Newton's original meaning (in fact, the entire theory was based on Newton's defnition of inertia). However, this resulted in a limitation inherent in special relativity: the principle of relativity could only apply to reference frames that were inertial in nature (meaning when no acceleration was present). In an attempt to address this limitation, Einstein proceeded to develop his general theory of relativity ("Te Foundation of the General Teory of Relativity," 1916), which ultimately provided a unifed theory for both inertial and noninertial (accelerated) reference frames. However, in order to accomplish this, in general relativity, Einstein found it necessary to redefne several fundamental concepts (such as gravity) in terms of a new concept of "curvature" of space-time, instead of the more traditional system of forces understood by Newton.[

188 As a result of this redefnition, Einstein also redefned the concept of "inertia" in terms of geodesic deviation instead, with some subtle but signifcant additional implications. Te result of this is that, according to general relativity, inertia is the gravitational coupling between matter and spacetime.

When dealing with very large scales, the traditional Newtonian idea of "inertia" does not actually apply and cannot necessarily be relied upon. Luckily, for suﬃciently small regions of spacetime, the special theory can be used and inertia still means the same (and works the same) as in the classical model.

Another profound conclusion of the theory of special relativity—perhaps the most well known—was that energy and mass are not separate things but are, in fact, interchangeable. But this new relationship also carried with it new implications for the concept of inertia. Te logical conclusion of special relativity was that if mass exhibits the principle of inertia, then inertia must also apply to energy. Tis theory, and subsequent experiments confrming some of its conclusions, have also served to radically expand the meaning of inertia to apply more widely and to include inertia of energy.

In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum. It is an important quantity in physics because it is a conserved quantity – the total angular momentum of a system remains constant unless acted on by an external torque.

In three dimensions, the angular momentum for a point particle is a pseudovector r×p, the cross product of the particle's position vector r (relative to some origin) and its momentum vector p = mv. Tis defnition can be applied to each point in continua like solids or fuids, or physical felds. Unlike momentum, angular momentum does depend on where the origin is chosen, since the particle's

3 7 o f 1 1 1 position is measured from it. Te angular momentum vector of a point particle is parallel and directly proportional to the angular velocity vector ω of the particle (how fast its angular position changes), where the constant of proportionality depends on both the mass of the particle and its distance from origin. For continuous rigid bodies, though, the spin angular velocity ω is proportional but not always parallel to the spin angular momentum of the object, making the constant of proportionality I (called the moment of inertia) a second-rank tensor rather than a scalar.

Angular momentum is additive; the total angular momentum of a system is the (pseudo)vector sum of the angular momenta. For continua or felds one uses integration. Te total angular momentum of any rigid body can be split into the sum of two main components: the angular momentum of the centre of mass (with a mass equal to the total mass) about the origin, plus the spin angular momentum of the object about the centre of mass.

Torque can be defned as the rate of change of angular momentum, analogous to force. Te conservation of angular momentum helps explain many observed phenomena, for example the increase in rotational speed of a spinning fgure skater as the skater's arms are contracted, the high rotational rates of neutron stars, the Coriolis eﬀect, and precession of tops and gyroscopes. Applications include the gyrocompass, control moment gyroscope, inertial guidance systems, reaction wheels, fying discs or Frisbees, and Earth's rotation to name a few. In general, conservation does limit the possible motion of a system, but does not uniquely determine what the exact motion is.

In quantum mechanics, angular momentum is an operator with quantized eigenvalues. Angular momentum is subject to the Heisenberg uncertainty principle, meaning that at any time, only one component can be measured with defnite precision; the other two cannot. Also, the "spin" of elementary particles does not correspond to literal spinning motion.

In quantum mechanics, the uncertainty principle, also known as Heisenberg's uncertainty principle or Heisenberg's indeterminacy principle, is any of a variety of mathematical inequalities[1] asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position x and momentum p, can be known.

Introduced frst in 1927, by the German physicist Werner Heisenberg, it states that the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa. Te formal inequality relating the standard deviation of position σx and the standard deviation of momentum σp was derived by Earle Hesse Kennard later that year and by Hermann Weyl in 1928:

(ħ is the reduced Planck constant, h / (2π)).

189 Historically, the uncertainty principle has been confused with a somewhat similar effect in physics, called the observer effect, which notes that measurements of certain systems cannot be made without affecting the systems, that is, without changing something in a system. Heisenberg utilized such an observer effect at the quantum level (see below) as a physical "explanation" of quantum uncertainty. It has since become clearer, however, that the uncertainty principle is inherent in the properties of all wave-like systems,[8] and that it arises in quantum mechanics simply due to the matter wave nature of all quantum objects. Tus, the uncertainty principle actually states a fundamental property of quantum systems, and is not a statement about the observational success of current technology. It must be emphasized that measurement does not mean only a process in which a physicist-observer takes part, but rather any interaction between classical and quantum objects regardless of any observer.

Since the uncertainty principle is such a basic result in quantum mechanics, typical experiments in quantum mechanics routinely observe aspects of it. Certain experiments, however, may deliberately test a particular form of the uncertainty principle as part of their main research program. Tese include, for example, tests of number–phase uncertainty relations in

3 8 o f 1 1 1 superconducting or quantum optics systems. Applications dependent on the uncertainty principle for their operation include extremely low-noise technology such as that required in gravitational wave interferometers.

Te Planck constant (denoted h, also called Planck's constant) is a physical constant that is the quantum of action, central in quantum mechanics.

First recognized in 1900 by Max Planck, it was conceived as the proportionality constant between the minimal increment of energy, E, of a hypothetical electrically charged oscillator in a cavity that contained black body radiation, and the frequency, f, of its associated electromagnetic wave. In 1905, the value E, the minimal energy increment of a hypothetical oscillator, was theoretically associated by Albert Einstein with a "quantum" or minimal element of the energy of the electromagnetic wave itself. Te light quantum behaved in some respects as an electrically neutral particle, as opposed to an electromagnetic wave. It was eventually called the photon.

Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. Te period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency. For example, if a newborn baby's heart beats at a frequency of 120 times a minute, its period—the time interval between beats—is half a second (that is, 60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio (sound) signals, radio waves, and light.

Symmetry is one of the most powerful tools in particle physics, because it has become evident that practically all laws of nature originate in symmetries. Violations of symmetry therefore present theoretical and experimental puzzles that lead to a deeper understanding of nature. Asymmetries in experimental measurements also provide powerful handles that are often relatively free from background or systematic uncertainties.

In mechanics, compression is the application of balanced inward ("pushing") forces to diﬀerent points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions. It is contrasted with tension or traction, the application of balanced outward ("pulling") forces; and with shearing forces, directed so as to displace layers of the material parallel to each other. Te compressive strength of materials and structures is an important engineering consideration.

In uniaxial compression, the forces are directed along one direction only, so that they act towards decreasing the object's length along that direction. Te compressive forces may also be applied in multiple directions; for example inwards along the edges of a plate or all over the side surface of a cylinder, so as to reduce its area (biaxial compression), or inwards over the entire surface of a body, so as to reduce its volume.

Technically, a material is under a state of compression, at some specifc point and along a specifc direction x, if the normal component of the stress vector across a surface with normal direction x is directed opposite to x. If the stress vector itself is opposite to x, the material is said to be under normal compression or pure compressive stress along x. In a solid, the amount of compression generally depends on the direction x, and the material may be under compression along some directions but under traction along others. If the stress vector is purely compressive and has the same magnitude for all directions, the material is said to be under isotropic or hydrostatic compression at that point. Tis is the only type of static compression that liquids and gases can bear

190 In a mechanical longitudinal wave, or compression wave, the medium is displaced in the wave's direction, resulting in areas of compression and rarefaction.

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Te holographic principle is a principle of string theories and a supposed property of quantum gravity that states that the description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region—preferably a light-like boundary like a gravitational horizon. First proposed by Gerard 't Hooft, it was given a precise string-theory interpretation by Leonard Susskind who combined his ideas with previous ones of 't Hooft and Charles Torn. As pointed out by Raphael Bousso, Torn observed in 1978 that string theory admits a lower- dimensional description in which gravity emerges from it in what would now be called a holographic way.

In a larger sense, the theory suggests that the entire universe can be seen as two-dimensional information on the cosmological horizon, the event horizon from which information may still be gathered and not lost due to the natural limitations of spacetime supporting a black hole, an observer and a given setting of these specifc elements,[clarifcation needed] such that the three dimensions we observe are an eﬀective description only at macroscopic scales and at low energies. Cosmological holography has not been made mathematically precise, partly because the particle horizon has a non-zero area and grows with time.

Te holographic principle was inspired by black hole thermodynamics, which conjectures that the maximal entropy in any region scales with the radius squared, and not cubed as might be expected. In the case of a black hole, the insight was that the informational content of all the objects that have fallen into the hole might be entirely contained in surface fuctuations of the event horizon. Te holographic principle resolves the black hole information paradox within the framework of string theory. However, there exist classical solutions to the Einstein equations that allow values of the entropy larger than those allowed by an area law, hence in principle larger than those of a black hole. Tese are the so-called "Wheeler's bags of gold". Te existence of such solutions conficts with the holographic interpretation, and their eﬀects in a quantum theory of gravity including the holographic principle are not yet fully understood. classical physics

Classical theory has at least two distinct meanings in physics. In the context of quantum mechanics, classical theory refers to theories of physics that do not use the quantisation paradigm, which includes classical mechanics and relativity. Likewise, classical feld theories, such as general relativity and classical electromagnetism, are those that do not use quantum mechanics. In the context of general and special relativity, classical theories are those that obey Galilean relativity.

Newton's laws of motion are three physical laws that, together, laid the foundation for classical mechanics. Tey describe the relationship between a body and the forces acting upon it, and its motion in response to those forces. More precisely, the frst law defnes the force qualitatively, the second law oﬀers a quantitative measure of the force, and the third asserts that a single isolated force doesn't exist. Tese three laws have been expressed in several ways, over nearly three centuries, and can be summarised as follows:

First law: In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force. Second law: In an inertial reference frame, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma. (It is assumed here that the mass m is constant – see below.)

Tird law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the frst body. Te three laws of motion were frst compiled by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), frst published in 1687. Newton used them to explain and investigate the motion of many physical objects and systems. For example, in the third volume of the text, Newton showed that these laws of motion, combined with his law of universal gravitation, explained Kepler's laws of planetary motion.

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Newton's law of universal gravitation states that a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.[note 1] Tis is a general physical law derived from empirical observations by what Isaac Newton called inductive reasoning.[1] It is a part of classical mechanics and was formulated in Newton's work Philosophiæ Naturalis Principia

191 Mathematica ("the Principia"), frst published on 5 July 1686. When Newton's book was presented in 1686 to the Royal Society, Robert Hooke made a claim that Newton had obtained the inverse square law from him.

In today's language, the law states: Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. Te force is proportional to the product of the two masses and inversely proportional to the square of the distance between them. Te frst test of Newton's theory of gravitation between masses in the laboratory was the Cavendish experiment conducted by the British scientist Henry Cavendish in 1798. It took place 111 years after the publication of Newton's Principia and approximately 71 years after his death.

Newton's law of gravitation resembles Coulomb's law of electrical forces, which is used to calculate the magnitude of the electrical force arising between two charged bodies. Both are inverse-square laws, where force is inversely proportional to the square of the distance between the bodies. Coulomb's law has the product of two charges in place of the product of the masses, and the electrostatic constant in place of the gravitational constant.

Newton's law has since been superseded by Albert Einstein's theory of general relativity, but it continues to be used as an excellent approximation of the eﬀects of gravity in most applications. Relativity is required only when there is a need for extreme precision, or when dealing with very strong gravitational felds, such as those found near extremely massive and dense objects, or at very close distances (such as Mercury's orbit around the Sun). quantum physics Quantum is computing interpreting heavenly information.

In physics, a quantum (plural: quanta) is the minimum amount of any physical entity involved in an interaction. Te fundamental notion that a physical property may be "quantized" is referred to as "the hypothesis of quantization". Tis means that the magnitude of the physical property can take on only discrete values consisting of integer multiples of one quantum.

For example, a photon is a single quantum of light (or of any other form of electromagnetic radiation), and can be referred to as a "light quantum". Similarly, the energy of an electron bound within an atom is also quantized, and thus can only exist in certain discrete values. Te fact that electrons can only exist at discrete energy levels in an atom causes atoms to be stable, and hence matter in general is stable.

Quantization is one of the foundations of the much broader physics of quantum mechanics. Quantization of the energy and its infuence on how energy and matter interact (quantum electrodynamics) is part of the fundamental framework for understanding and describing nature.

Quantum mechanics (QM; also known as quantum physics or quantum theory), including quantum feld theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.

Classical physics (the physics existing before quantum mechanics) is a set of fundamental theories which describes nature at ordinary (macroscopic) scale. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics diﬀers from classical physics in that: energy, momentum and other quantities of a system may be restricted to discrete values (quantization), objects have characteristics of both 4 1 o f 1 1 1 particles and waves (wave-particle duality), and there are limits to the precision with which quantities can be known (uncertainty principle).

Quantum mechanics gradually arose from theories to explain observations which could not be reconciled with classical physics, such as Max Planck's solution in 1900 to the black-body radiation problem, and from the correspondence between energy and frequency in Albert Einstein's 1905 paper which explained the photoelectric eﬀect. Early quantum theory was profoundly re-conceived in the mid-1920s by Erwin Schrödinger, Werner Heisenberg, Max Born and others. Te modern theory is formulated in various specially developed mathematical formalisms. In one of them, a mathematical function, the wave function, provides information about the probability amplitude of position, momentum, and other physical properties of a particle.

Important applications of quantum theory include quantum chemistry, superconducting magnets, light-emitting diodes, and the laser, the transistor and semiconductors such as the microprocessor, medical and research imaging such as magnetic resonance imaging and electron microscopy. Explanations for many biological and physical phenomena are rooted in the nature of the chemical bond, most notably the macro-molecule DNA.

192 In nuclear physics, nuclear fusion is a reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles (neutrons or protons). Te difference in mass between the reactants and products is manifested as the release of large amounts of energy. Tis difference in mass arises due to the difference in atomic "binding energy" between the atomic nuclei before and after the reaction. Fusion is the process that powers active or "main sequence" stars, or other high magnitude stars.

A fusion process that produces a nucleus lighter than iron-56 or nickel-62 will generally yield a net energy release. Tese elements have the smallest mass per nucleon and the largest binding energy per nucleon, respectively. Fusion of light elements toward these releases energy (an exothermic process), while a fusion producing nuclei heavier than these elements will result in energy retained by the resulting nucleons, and the resulting reaction is endothermic. Te opposite is true for the reverse process, nuclear fssion. Tis means that the lighter elements, such as hydrogen and helium, are in general more fusible; while the heavier elements, such as uranium and plutonium, are more fssionable. Te extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron.

Dark matter is a hypothetical type of matter distinct from ordinary matter such as protons, neutrons, electrons, and neutrinos.

Dark matter has never been directly observed; however, its existence would explain a number of otherwise puzzling astronomical observations.Te name refers to the fact that it does not emit or interact with observable electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum.

Te standard model of cosmology indicates that the total mass–energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Tus, dark matter constitutes 84.5%[note 1] of total mass, while dark energy plus dark matter constitute 95.1% of total mass– energy content. Te great majority of ordinary matter in the universe is also unseen. Visible stars and gas inside galaxies and clusters account for less than 10% of the ordinary matter contribution to the mass- energy density of the universe. Te most widely accepted hypothesis on the form for dark matter is that it is composed of weakly interacting massive particles, WIMPs, that interact only through gravity and the weak force. Te dark matter hypothesis plays a central role in current modeling of cosmic structure formation, galaxy formation and evolution, and on explanations of the anisotropies observed in the cosmic microwave background, CMB. All these lines of evidence suggest that galaxies, galaxy clusters, and the universe as a whole contain far more matter than that which is observable via electromagnetic signals. Many experiments to detect proposed dark

4 2 o f 1 1 1 matter particles through non-gravitational means are under way; however, no dark matter particle has been conclusively identifed.

Although the existence of dark matter is generally accepted by most of the astronomical community, a minority of astronomers, motivated by the lack of conclusive identifcation of dark matter, or by observations that don't ft the model, argue for various modifcations of the standard laws of general relativity, such as MOND, TeVeS, and conformal gravity that attempt to account for the observations without invoking additional matter.

In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain the observations since the 1990s indicating that the universe is expanding at an accelerating rate.

Assuming that the standard model of cosmology is correct, the best current measurements indicate that dark energy contributes 68.3% of the total energy in the present-day observable universe. Te mass–energy of dark matter and ordinary (baryonic) matter contribute 26.8% and 4.9%, respectively, and other components such as neutrinos and photons contribute a very small amount. Te density of dark energy (~ 7 × 10−30 g/cm3) is very low, much less than the density of ordinary matter or dark matter within galaxies. However, it dominates the mass–energy of the universe because it is uniform across space.

Two proposed forms for dark energy are the cosmological constant, representing a constant energy density flling space homogeneously, and scalar felds such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space. Contributions from scalar felds that are constant in space are usually also included in the cosmological constant. Te cosmological constant can be formulated to be equivalent to the zero-point radiation of space i.e. the vacuum energy. Scalar felds that change in space can be diﬃcult to distinguish from a cosmological constant because the change may be extremely slow.

193 An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are very small; typical sizes are around 100 picometers (a ten-billionth of a meter, in the short scale).

Atoms are small enough that attempting to predict their behavior using classical physics – as if they were billiard balls, for example – gives noticeably incorrect predictions due to quantum eﬀects. Trough the development of physics, atomic models have incorporated quantum principles to better explain and predict the behavior.

Every atom is composed of a nucleus and one or more electrons bound to the nucleus. Te nucleus is made of one or more protons and typically a similar number of neutrons. Protons and neutrons are called nucleons. More than 99.94% of an atom's mass is in the nucleus. Te protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, that atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.

An ion (/ˈaɪən, -ɒn/)[1] is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons). A cation is a positively-charged ion, while an anion is negatively charged. Because of their opposite electric charges, cations and anions attract each other and readily form ionic compounds, such as salts.

Ions can be created by chemical means, such as the dissolution of a salt into water, or by physical means, such as passing a direct current through a conducting solution, which will dissolve the anode via ionization .

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Te electrons of an atom are attracted to the protons in an atomic nucleus by this electromagnetic force. Te protons and neutrons in the nucleus are attracted to each other by a diﬀerent force, the nuclear force, which is usually stronger than the electromagnetic force repelling the positively charged protons from one another. Under certain circumstances, the repelling electromagnetic force becomes stronger than the nuclear force, and nucleons can be ejected from the nucleus, leaving behind a diﬀerent element: nuclear decay resulting in nuclear transmutation.

Te number of protons in the nucleus defnes to what chemical element the atom belongs: for example, all copper atoms contain 29 protons. Te number of neutrons defnes the isotope of the element. Te number of electrons infuences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules. Te ability of atoms to associate and dissociate is responsible for most of the physical changes observed in nature and is the subject of the discipline of chemistry.

Te atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko[1] and Werner Heisenberg. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud. Protons and neutrons are bound together to form a nucleus by the nuclear force.

Te diameter of the nucleus is in the range of 1.75 fm (1.75×10−15 m) for hydrogen (the diameter of a single proton)[7] to about 15 fm for the heaviest atoms, such as uranium. Tese dimensions are much smaller than the diameter of the atom itself (nucleus + electron cloud), by a factor of about 23,000 (uranium) to about 145,000 (hydrogen).

Te branch of physics concerned with the study and understanding of the atomic nucleus, including its composition and the forces which bind it together, is called nuclear physics.

Te electron is a subatomic particle, whose electric charge is negative one elementary charge. Electrons belong to the frst generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. Te electron has a mass that is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value, expressed in units of the reduced Planck constant, ħ. As it is a fermion, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be diﬀracted like light. Te wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy.

194 Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions. Since an electron has charge, it has a surrounding electric feld, and if that electron is moving relative to an observer it will generate a magnetic feld. Electromagnetic felds produced from other sources will aﬀect the motion of an electron according to the Lorentz force law. Electrons radiate or absorb energy in the form of photons when they are accelerated. Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic felds. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as electronics, welding, cathode ray tubes, electron microscopes, radiation therapy, lasers, gaseous ionization detectors and particle accelerators.

Interactions involving electrons with other subatomic particles are of interest in felds such as chemistry and nuclear physics. Te Coulomb force interaction between the positive protons within 4 4 o f 1 1 1 atomic nuclei and the negative electrons without, allows the composition of the two known as atoms. Ionization or diﬀerences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. Te exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding. In 1838, British natural philosopher Richard Laming frst hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Irish physicist George Johnstone Stoney named this charge 'electron' in 1891, and J. J. Tomson and his team of British physicists identifed it as a particle in 1897. Electrons can also participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere. Te antiparticle of the electron is called the positron; it is identical to the electron except that it carries electrical and other charges of the opposite sign. When an electron collides with a positron, both particles can be totally annihilated, producing gamma ray photons.

A proton is a subatomic particle, symbol p or p+ with a positive electric charge of +1e elementary charge and mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collectively referred to as "nucleons".

One or more protons are present in the nucleus of every atom; they are a necessary part of the nucleus. Te number of protons in the nucleus is the defning property of an element, and is referred to as the atomic number (represented by the symbol Z). Since each element has a unique number of protons, each element has its own unique atomic number.

Te word proton is Greek for "frst", and this name was given to the hydrogen nucleus by Ernest Rutherford in 1920. In previous years, Rutherford had discovered that the hydrogen nucleus (known to be the lightest nucleus) could be extracted from the nuclei of nitrogen by atomic collisions. Protons were therefore a candidate to be a fundamental particle, and hence a building block of nitrogen and all other heavier atomic nuclei.

In the modern Standard Model of particle physics, protons are hadrons, and like neutrons, the other nucleon (particles present in atomic nuclei), are composed of three quarks. Although protons were originally considered fundamental or elementary particles, they are now known to be composed of three valence quarks: two up quarks of charge +2/3 e and one down quark of charge –1/3 e. Te rest masses of quarks contribute only about 1% of a proton's mass, however.[3] Te remainder of a proton's mass is due to quantum chromodynamics binding energy, which includes the kinetic energy of the quarks and the energy of the gluon felds that bind the quarks together. Because protons are not fundamental particles, they possess a physical size, though not a defnite one; the root mean square charge radius of a proton is about 0.84–0.87 fm or 0.84×10−15 to 0.87×10−15 m.

At sufficiently low temperatures, free protons will bind to electrons. However, the character of such bound protons does not change, and they remain protons. A fast proton moving through matter will slow by interactions with electrons and nuclei, until it is captured by the electron cloud of an atom. Te result is a protonated atom, which is a chemical compound of hydrogen. In vacuum, when free electrons are present, a sufficiently slow proton may pick up a single free electron, becoming a neutral hydrogen atom, which is chemically a free radical. Such "free hydrogen atoms" tend to react chemically with many other types of atoms at sufficiently low energies. When free hydrogen atoms react with each other, they form neutral hydrogen molecules (H2), which are the most common molecular component of molecular clouds in interstellar space.

Te early stages of physics are contained in descriptions below, they fundamentals before are often decription’s of ‘mixes’ of the ones above, please fnd it interesting anyway - can you sort out the orders within? Tere are 7 in a lepton.

Te neutron is a subatomic particle, symbol n or n0, with no net electric charge and a mass slightly larger than that of a proton. Protons and neutrons constitute the

195 nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. Teir properties and interactions are described by nuclear physics.

Te chemical and nuclear properties of the nucleus are determined by the number of protons, called the atomic number, and the number of neutrons, called the neutron number. Te atomic mass number is the total number of nucleons. For example, carbon has atomic number 6, and its abundant carbon-12 isotope has 6 neutrons, whereas its rare carbon-13 isotope has 7 neutrons. Some elements occur in nature with only one stable isotope, such as fuorine. Other elements occur with many stable isotopes, such as tin with ten stable isotopes.

Within the nucleus, protons and neutrons are bound together through the nuclear force and, with the exception of the single-proton hydrogen atom, neutrons are required for the stability of nuclei. Neutrons are produced copiously in nuclear fssion and fusion. Tey are a primary contributor to the nucleosynthesis of chemical elements within stars through fssion, fusion, and neutron capture processes.

Te neutron is essential to the production of nuclear power. In the decade after the neutron was discovered by James Chadwick in 1932,[6] neutrons were used to induce many diﬀerent types of nuclear transmutations. With the discovery of nuclear fssion in 1938,[7] it was quickly realized that, if a fssion event produced neutrons, each of these neutrons might cause further fssion events, etc., in a cascade known as a nuclear chain reaction.[8] Tese events and fndings led to the frst self-sustaining nuclear reactor (Chicago Pile-1, 1942) and the frst nuclear weapon (Trinity, 1945).

Free neutrons, or individual neutrons free of the nucleus, are a form of ionizing radiation and, as such, are a biological hazard, depending upon dose.[8] A small natural "neutron background" fux of free neutrons exists on Earth, caused by cosmic ray showers, and by the natural radioactivity of spontaneously fssionable elements in the Earth's crust.[9] Dedicated neutron sources like neutron generators, research reactors and spallation sources produce free neutrons for use in irradiation and in neutron scattering experiments.

In chemistry and physics, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus. Te number of nucleons in a nucleus defnes an isotope's mass number (nucleon number).

Until the 1960s, nucleons were thought to be elementary particles, not made up of smaller parts. Now they are known to be composite particles, made of three quarks bound together by the so- called strong interaction. Te interaction between two or more nucleons is called internucleon interactions or nuclear force, which is also ultimately caused by the strong interaction. (Before the discovery of quarks, the term "strong interaction" referred to just internucleon interactions.)

Nucleons sit at the boundary where particle physics and nuclear physics overlap. Particle physics, particularly quantum chromodynamics, provides the fundamental equations that explain the properties of quarks and of the strong interaction. Tese equations explain quantitatively how quarks can bind together into protons and neutrons (and all the other hadrons). However, when multiple nucleons are assembled into an atomic nucleus (nuclide), these fundamental equations become too diﬃcult to solve directly (see lattice QCD). Instead, nuclides are studied within nuclear physics, which studies nucleons and their interactions by approximations and models, such as the nuclear shell model. Tese models can successfully explain nuclide properties, for example, whether or not a certain nuclide undergoes radioactive decay.

Te proton and neutron are both baryons and both . One carries a positive net charge and the other carries a zero net charge; the proton's mass is only 0.1% less than the neutron's. Tus, they can be viewed as two states of the same nucleon, and together form an isospin doublet (I = 1⁄2). In isospin space, neutrons can be transformed into protons via SU symmetries, and vice versa. Tese nucleons are acted upon equally by the strong interaction, which is invariant under rotation in isospin space. According to the Noether theorem, isospin is conserved with respect to the strong interaction.

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Ions consisting of only a single atom are atomic or monatomic ions. If they consist of two or more atoms, then they are called molecular ions or polyatomic ions.

In the case of physical ionization of a medium such as a gas, what are known as "ion pairs" are created by ion impact, and each pair consists of a free electron and a positive ion.

A baryon is a composite subatomic particle made up of three quarks (a triquark, as distinct from mesons, which are composed of one quark and one antiquark). Baryons and mesons belong to the hadron family of particles, which are the quark-based particles. Te name "baryon" comes from the Greek word for "heavy" (βαρύς, barys), because, at the time of their naming, most known elementary particles had lower masses than the baryons. 196 As quark-based particles, baryons participate in the strong interaction, whereas leptons, which are not quark-based, do not. Te most familiar baryons are the protons and neutrons that make up most of the mass of the visible matter in the universe. Electrons (the other major component of the atom) are leptons.

Each baryon has a corresponding antiparticle (antibaryon) where quarks are replaced by their corresponding antiquarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark.

In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Tese particles obey the Pauli exclusion principle. Fermions include all quarks and leptons, as well as all composite particles made of an odd number of these, such as all baryons and many atoms and nuclei. Fermions diﬀer from bosons, which obey Bose–Einstein statistics.

In particle physics, a hadron /ˈhædrɒn/ (About this sound listen) (Greek: ἁδρός, hadrós, "stout, thick") is a composite particle made of quarks held together by the strong force in a similar way as molecules are held together by the electromagnetic force.

Hadrons are categorized into two families: baryons, made of three quarks, and mesons, made of one quark and one antiquark. Protons and neutrons are examples of baryons; pions are an example of a meson. Hadrons containing more than three valence quarks (exotic hadrons) have been discovered in recent years. A tetraquark state (an exotic meson), named the Z(4430)−, was discovered in 2007 by the Belle Collaboration[1] and confrmed as a resonance in 2014 by the LHCb collaboration. Two pentaquark states (exotic baryons), named P+ c(4380) and P+ c(4450), were discovered in 2015 by the LHCb collaboration.Tere are several more exotic hadron candidates, and other colour-singlet quark combinations may also exist.

Of the hadrons, protons are stable, and neutrons bound within atomic nuclei are stable. Other hadrons are unstable under ordinary conditions; free neutrons decay with a half-life of about 611 seconds. Experimentally, hadron physics is studied by colliding protons or nuclei of heavy elements such as lead, and detecting the debris in the produced particle showers.

In particle physics, mesons (/ˈmiːzɒnz/ or /ˈmɛzɒnz/) are hadronic subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of quark sub-particles, they have a physical size, with a diameter of roughly one femtometer, which is about 1.2 times the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay (sometimes through mediating particles) to form electrons and neutrinos. Uncharged mesons may decay to photons. Both of these decays imply that color is no longer a property of the byproducts.

Outside the nucleus, mesons appear in nature only as short-lived products of very high-energy collisions between particles made of quarks, such as cosmic rays (high-energy protons and

4 7 o f 1 1 1 neutrons) and ordinary matter. Mesons are also frequently produced artifcially in high-energy particle accelerators in the collisions of protons, anti-protons, or other particles.

Mesons are the associated quantum-feld particles that transmit the nuclear force between hadrons that pull those together into a nucleus. Teir eﬀect is analogous to photons that are the force carriers that transmit the electromagnetic force of attraction between oppositely charged protons and electrons that allow individual atoms to exist, and further, to pull atoms together into molecules. Higher energy (more massive) mesons were created momentarily in the Big Bang, but are not thought to play a role in nature today. However, such heavy mesons are regularly created in particle accelerator experiments, in order to understand the nature of the heavier types of quark that compose the heavier mesons.

Mesons are part of the hadron particle family, and are defned simply as particles composed of two quarks. Te other members of the hadron family are the baryons: subatomic particles composed of three quarks. Some experiments show evidence of exotic mesons, which do not have the conventional valence quark content of one quark and one antiquark.

Because quarks have a spin of 1⁄2, the diﬀerence in quark-number between mesons and baryons results in conventional two- quark mesons being bosons, whereas baryons are fermions.

197 Each type of meson has a corresponding antiparticle (antimeson) in which quarks are replaced by their corresponding antiquarks and vice versa. For example, a positive pion is made of one up quark and one down antiquark; and its corresponding antiparticle, the negative pion (π−), is made of one up antiquark and one down quark.

Because mesons are composed of quarks, they participate in both the weak and strong interactions. Mesons with net electric charge also participate in the electromagnetic interaction. Mesons are classifed according to their quark content, total angular momentum, parity and various other properties, such as C-parity and G-parity. Although no meson is stable, those of lower mass are nonetheless more stable than the more massive, and hence are easier to observe and study in particle accelerators or in cosmic ray experiments. Mesons are also typically less massive than baryons, meaning that they are more easily produced in experiments, and thus exhibit certain higher-energy phenomena more readily than do baryons. For example, the charm quark was frst seen in the J/Psi meson in 1974,[2][3] and the bottom quark in the upsilon meson in 1977.

A fermion can be an elementary particle, such as the electron, or it can be a composite particle, such as the proton. According to the spin-statistics theorem in any reasonable relativistic quantum feld theory, particles with integer spin are bosons, while particles with half-integer spin are fermions.

In addition to the spin characteristic, fermions have another specifc property: they possess conserved baryon or lepton quantum numbers. Terefore, what is usually referred to as the spin statistics relation is in fact a spin statistics-quantum number relation.

As a consequence of the Pauli exclusion principle, only one fermion can occupy a particular quantum state at any given time. If multiple fermions have the same spatial probability distribution, then at least one property of each fermion, such as its spin, must be diﬀerent. Fermions are usually associated with matter, whereas bosons are generally force carrier particles, although in the current state of particle physics the distinction between the two concepts is unclear. Weakly interacting fermions can also display bosonic behavior under extreme conditions. At low temperature fermions show superfuidity for uncharged particles and superconductivity for charged particles.

Composite fermions, such as protons and neutrons, are the key building blocks of everyday matter. 4 8 o f 1 1 1

Te name fermion was coined by English theoretical physicist Paul Dirac from the surname of Italian physicist Enrico Fermi.

A tachyon /ˈtæki.ɒn/ or tachyonic particle is a hypothetical particle that always moves faster than light. Most physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics. If such particles did exist, they could be used to build a tachyonic antitelephone and send signals faster than light, which (according to special relativity) would lead to violations of causality.

Te possibility of particles moving faster than light was frst proposed by O. M. P. Bilaniuk, V. K. Deshpande, and E. C. G. Sudarshan in 1962, although the term they used for it was "meta- particle". In the 1967 paper that coined the term, Gerald Feinberg proposed that tachyonic particles could be quanta of a quantum feld with imaginary mass. However, it was soon realized that excitations of such imaginary mass felds do not in fact propagate faster than light, and instead represent an instability known as tachyon condensation. Nevertheless, in modern physics the term "tachyon" often refers to imaginary mass felds rather than to faster-than-light particles. Such felds have come to play a signifcant role in modern physics.

Te term comes from the Greek: ταχύ, tachy, meaning "rapid". Te complementary particle types are called luxons (which always move at the speed of light) and bradyons (which always move slower than light); both of these particle types are known to exist.

Despite theoretical arguments against the existence of faster-than-light particles, experiments have been conducted to search for them. No compelling evidence for their existence has been found. In September 2011, it was reported that a tau neutrino had travelled faster than the speed of light in a major release by CERN; however, later

A quark (/kwɔːrk, kwɑːrk/) is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as color confnement, quarks are never directly observed or found in isolation; they can be found only within hadrons, such as baryons (of which protons and neutrons are examples) and mesons. For this reason, much of what is known about quarks has been drawn from observations of the hadrons themselves.

Quarks have various intrinsic properties, including electric charge, mass, color charge, and spin. Quarks are the only elementary particles in the Standard Model of particle physics to experience all four fundamental interactions, also known as 198 fundamental forces (electromagnetism, gravitation, strong interaction, and weak interaction), as well as the only known particles whose electric charges are not integer multiples of the elementary charge.

Tere are six types of quarks, known as favors: up, down, strange, charm, top, and bottom. Up and down quarks have the lowest masses of all quarks. Te heavier quarks rapidly change into up and down quarks through a process of particle decay: the transformation from a higher mass state to a lower mass state. Because of this, up and down quarks are generally stable and the most common in the universe, whereas strange, charm, bottom, and top quarks can only be produced in high energy collisions (such as those involving cosmic rays and in particle accelerators). For every quark favor there is a corresponding type of antiparticle, known as an antiquark, that diﬀers from the quark only in that some of its properties have equal magnitude but opposite sign.

Te quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in 1964. Quarks were introduced as parts of an ordering scheme for hadrons, and there was little evidence for their physical existence until deep inelastic scattering experiments at the Stanford Linear Accelerator Center in 1968. Accelerator experiments have provided evidence for all six favors. Te top quark was the last to be discovered at Fermilab in 1995.

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A lepton is an elementary, half-integer spin (spin 1⁄2) particle that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. Te best known of all leptons is the electron.

Tere are six types of leptons, known as favours, forming three generations. Te frst generation is the electronic leptons, comprising the electron (e−) and electron neutrino (νe); the second is the muonic leptons, comprising the muon (μ−) and muon neutrino (νμ); and the third is the tauonic leptons, comprising the tau (τ−) and the tau neutrino (ν τ). Electrons have the least mass of all the charged leptons. Te heavier muons and taus will rapidly change into electrons and neutrinos through a process of particle decay: the transformation from a higher mass state to a lower mass state. Tus electrons are stable and the most common charged lepton in the universe, whereas muons and taus can only be produced in high energy collisions (such as those involving cosmic rays and those carried out in particle accelerators).

Leptons have various intrinsic properties, including electric charge, spin, and mass. Unlike quarks however, leptons are not subject to the strong interaction, but they are subject to the other three fundamental interactions: gravitation, electromagnetism (excluding neutrinos, which are electrically neutral), and the weak interaction.

For every lepton favor there is a corresponding type of antiparticle, known as an antilepton, that diﬀers from the lepton only in that some of its properties have equal magnitude but opposite sign. According to certain theories, neutrinos may be their own antiparticle. It is not currently known whether this is the case.

Te frst charged lepton, the electron, was theorized in the mid-19th century by several scientists and was discovered in 1897 by J. J. Tomson. Te next lepton to be observed was the muon, discovered by Carl D. Anderson in 1936, which was classifed as a meson at the time. After investigation, it was realized that the muon did not have the expected properties of a meson, but rather behaved like an electron, only with higher mass. It took until 1947 for the concept of "leptons" as a family of particle to be proposed. Te frst neutrino, the electron neutrino, was proposed by Wolfgang Pauli in 1930 to explain certain characteristics of beta decay. It was frst observed in the Cowan–Reines neutrino experiment conducted by Clyde Cowan and Frederick Reines in 1956. Te muon neutrino was discovered in 1962 by Leon M. Lederman, Melvin Schwartz, and Jack Steinberger, and the tau discovered between 1974 and 1977 by Martin Lewis Perl and his colleagues from the Stanford Linear Accelerator Center and Lawrence Berkeley National Laboratory. Te tau neutrino remained elusive until July 2000, when the DONUT collaboration from Fermilab announced its discovery.

Leptons are an important part of the Standard Model. Electrons are one of the components of atoms, alongside protons and neutrons. Exotic atoms with muons and taus instead of electrons can also be synthesized, as well as lepton–antilepton particles such as positronium.

A gluon /ˈɡluːɒn/ is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quarks. It is analogous to the exchange of photons in the electromagnetic force between two charged particles. In layman's terms, they "glue" quarks together, forming protons and neutrons.

In technical terms, gluons are vector gauge bosons that mediate strong interactions of quarks in quantum chromodynamics (QCD). Gluons themselves carry the color charge of the strong interaction. Tis is unlike the photon, which mediates the 199 electromagnetic interaction but lacks an electric charge. Gluons therefore participate in the strong interaction in addition to mediating it, making QCD signifcantly harder to analyze than QED (quantum electrodynamics).

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In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: π) is any of three subatomic particles: π0, π+, and π−. Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more generally, the lightest hadrons. Tey are unstable, with the charged pions π+ and π− decaying with a mean lifetime of 26 nanoseconds (2.6×10−8 seconds), and the neutral pion π0 decaying with a much shorter lifetime of 8.4×10−17 seconds. Charged pions most often decay into muons and muon neutrinos, while neutral pions generally decay into gamma rays.

Te exchange of virtual pions, along with the vector, rho and omega mesons, provides an explanation for the residual strong force between nucleons. Pions are not produced in radioactive decay, but are commonly produced in high energy accelerators in collisions between hadrons. All types of pions are also produced in natural processes when high energy cosmic ray protons and other hadronic cosmic ray components interact with matter in the Earth's atmosphere. Recently, the detection of characteristic gamma rays originating from the decay of neutral pions in two supernova remnants has shown that pions are produced copiously after supernovas, most probably in conjunction with production of high energy protons that are detected on Earth as cosmic rays.

Te concept of mesons as the carrier particles of the nuclear force was frst proposed in 1935 by Hideki Yukawa. While the muon was frst proposed to be this particle after its discovery in 1936, later work found that it did not participate in the strong nuclear interaction. Te pions, which turned out to be examples of Yukawa's proposed mesons, were discovered later: the charged pions in 1947, and the neutral pion in 1950.

Gamma rays (also called gamma radiation), denoted by the lower-case Greek letter gamma (γ or {\displaystyle \gamma } \gamma ), are penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei. It consists of photons in the highest observed range of photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation gamma rays. Rutherford had previously discovered two other types of radioactive decay, which he named alpha rays and beta rays.

Te decay of an atomic nucleus from a high energy state to a lower energy state, a process called gamma decay, produces gamma radiation.

Gamma rays ionize atoms (they are ionizing radiation), and are thus biologically hazardous.

Natural sources of gamma rays on Earth are observed in the gamma decay of radionuclides and secondary radiation from atmospheric interactions with cosmic ray particles. Tere are rare terrestrial natural sources, such as lightning strikes and terrestrial gamma-ray fashes, that produce gamma rays not of a nuclear origin. Additionally, gamma rays are produced by a number of astronomical processes in which very high-energy electrons are produced, that in turn cause secondary gamma rays via bremsstrahlung, inverse Compton scattering, and synchrotron radiation. However, a large fraction of such astronomical gamma rays are screened by Earth's atmosphere and can only be detected by spacecraft. Gamma rays are produced by nuclear fusion in stars including the Sun (such as the CNO cycle), but are absorbed or inelastically scattered by the stellar material, reducing their energy, before escaping and are not observable from Earth as gamma rays.

Gamma rays typically have energies above 100 keV, and therefore have frequencies above 10 exahertz (or >1019 Hz) and wavelengths less than 10 picometers (10−11 m), which is less than the diameter of an atom.[clarifcation needed] However, this is not a strict defnition, but rather only a rule-of-thumb description for natural processes. Electromagnetic radiation from radioactive decay of atomic nuclei is referred to as "gamma rays" no matter its energy, so that there is no lower limit to gamma energy derived from radioactive decay. Tis radiation commonly has energy of a few hundred keV, and almost always less than 10 MeV. In astronomy, gamma rays are defned by their 5 1 o f 1 1 1 energy, and no production process needs to be specifed. Te energies of gamma rays from astronomical sources range to over 10 TeV, an energy far too large to result from radioactive decay.[1] A notable example is the extremely powerful bursts of high-energy radiation referred to as long duration gamma-ray bursts, of energies higher than can be produced by radioactive decay. Tese bursts of gamma rays are thought to be due to the collapse of stars called hypernovae.

Many common depictions of the electromagnetic spectrum show gamma rays as higher in energy (hence are higher in frequency and smaller in wavelength) than X-rays. Tis historically allowed a clear distinction between X-rays and gamma rays. Today, the research literature often describes photons depending on their source. While astronomers usually hold to the 200 historical convention (often the source or production mechanism of the radiation is unknown), the physics literature often uses the term historically associated with the method of production. For example, one group of scientists might describe a 1 MeV photon as a gamma ray, while another group use the term X-ray.

In particle physics, every type of particle has an associated antiparticle with the same mass but with opposite physical charges (such as electric charge). For example, the antiparticle of the electron is the antielectron (which is often referred to as positron). While the electron has a negative electric charge, the positron has a positive electric charge, and is produced naturally in certain types of radioactive decay. Te opposite is also true: the antiparticle of the positron is the electron.

Some particles, such as the photon, are their own antiparticle. Otherwise, for each pair of antiparticle partners, one is designated as normal matter (the kind we are made of), and the other (usually given the prefx "anti-") as antimatter.

Particle–antiparticle pairs can annihilate each other, producing photons; since the charges of the particle and antiparticle are opposite, total charge is conserved. For example, the positrons produced in natural radioactive decay quickly annihilate themselves with electrons, producing pairs of gamma rays, a process exploited in positron emission tomography.

Te laws of nature are very nearly symmetrical with respect to particles and antiparticles. For example, an antiproton and a positron can form an antihydrogen atom, which is believed to have the same properties as a hydrogen atom. Tis leads to the question of why the formation of matter after the Big Bang resulted in a universe consisting almost entirely of matter, rather than being a half-and-half mixture of matter and antimatter. Te discovery of Charge Parity violation helped to shed light on this problem by showing that this symmetry, originally thought to be perfect, was only approximate.

Because charge is conserved, it is not possible to create an antiparticle without either destroying another particle of the same charge (as is for instance the case when antiparticles are produced naturally via beta decay or the collision of cosmic rays with Earth's atmosphere), or by the simultaneous creation of both a particle and its antiparticle, which can occur in particle accelerators such as the Large Hadron Collider at CERN.

Although particles and their antiparticles have opposite charges, electrically neutral particles need not be identical to their antiparticles. Te neutron, for example, is made out of quarks, the antineutron from antiquarks, and they are distinguishable from one another because neutrons and antineutrons annihilate each other upon contact. However, other neutral particles are their own antiparticles, such as photons, Z0 bosons, π0 mesons, and hypothetical gravitons and some hypothetical WIMPs.

In quantum mechanics, a boson (/ˈboʊsɒn/,[1] /ˈboʊzɒn/[2]) is a particle that follows Bose–Einstein statistics. Bosons make up one of the two classes of particles, the other being fermions.

Examples of bosons include fundamental particles such as photons, gluons, and W and Z bosons (the four force-carrying gauge bosons of the Standard Model), the recently discovered Higgs 5 2 o f 1 1 1 boson, and the hypothetical graviton of quantum gravity. Some composite particles are also bosons, such as mesons and stable nuclei of even mass number such as deuterium (with one proton and one neutron, mass number = 2), helium-4, or lead-208[Note 1]; as well as some quasiparticles (e.g. Cooper pairs, plasmons, and phonons).

An important characteristic of bosons is that their statistics do not restrict the number of them that occupy the same quantum state. Tis property is exemplifed by helium-4 when it is cooled to become a superfuid.[5] Unlike bosons, two identical fermions cannot occupy the same quantum space. Whereas the elementary particles that make up matter (i.e. leptons and quarks) are fermions, the elementary bosons are force carriers that function as the 'glue' holding matter together. [6] Tis property holds for all particles with integer spin (s = 0, 1, 2, etc.) as a consequence of the spin–statistics theorem. When a gas of Bose particles is cooled down to temperatures very close to absolute zero then the kinetic energy of the particles decreases to a negligible amount and they condense into a lowest energy level state. Tis state is called Bose- Einstein condensation. It is believed that this property is the explanation of superfuidity.

Te name boson was coined by Paul Dirac to commemorate the contribution of Satyendra Nath Bose, a physicist and professor at University of Dhaka, in developing, with Albert Einstein, Bose– Einstein statistics—which theorizes the characteristics of elementary particles.

In physics, the fundamental interactions, also known as fundamental forces, are the interactions that do not appear to be reducible to more basic interactions. Tere are four fundamental interactions known to exist: the gravitational and electromagnetic interactions, which produce signifcant long-range forces whose eﬀects can be seen directly in everyday life, 201 and the strong and weak interactions, which produce forces at minuscule, subatomic distances and govern nuclear interactions. Some scientists speculate that a ffth force might exist but if so, it is not widely accepted nor proven.

Each of the known fundamental interactions can be described mathematically as a feld. Te gravitational force is attributed to the curvature of spacetime, described by Einstein's general theory of relativity. Te other three are discrete quantum felds, and their interactions are mediated by elementary particles described by the Standard Model of particle physics.

Within the Standard Model, the strong interaction is carried by a particle called the gluon, and is responsible for the binding of quarks together to form hadrons, such as protons and neutrons. As a residual eﬀect, it creates the nuclear force that binds the latter particles to form atomic nuclei. Te weak interaction is carried by particles called W and Z bosons, and also acts on the nucleus of atoms, mediating radioactive decay. Te electromagnetic force, carried by the photon, creates electric and magnetic felds, which are responsible for chemical bonding and electromagnetic waves, including visible light, and forms the basis for electrical technology. Although the electromagnetic force is far stronger than gravity, it tends to cancel itself out within large objects, so over the largest distances (on the scale of planets and galaxies), gravity tends to be the dominant force.

All four fundamental forces are believed to be related, and to unite into a single force at high energies on a minuscule scale, the Planck scale, but particle accelerators cannot produce the enormous energies required to experimentally probe this. Eﬀorts to devise a common theoretical framework that would explain the relation between the forces are perhaps the greatest goal of theoretical physicists today. Te weak and electromagnetic forces have already been unifed with the electroweak theory of Sheldon Glashow, Abdus Salam, and Steven Weinberg for which they received the 1979 Nobel Prize in physics. Progress is currently being made in uniting the electroweak and strong felds within a Grand Unifed Teory (GUT). A bigger challenge is to fnd a way to quantize the gravitational feld, resulting in a theory of quantum gravity (QG) which would unite gravity in a common theoretical framework with the other three forces. Some theories, notably string theory, seek both QG and GUT within one framework, unifying all four fundamental interactions along with mass generation within a theory of everything (ToE).

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Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward (or gravitate toward) one another, including objects ranging from atoms and photons, to planets and stars. Since energy and mass are equivalent, all forms of energy (including light) cause gravitation and are under the infuence of it. On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the ocean tides. Te gravitational attraction of the original gaseous matter present in the Universe caused it to begin coalescing, forming stars – and for the stars to group together into galaxies – so gravity is responsible for many of the large scale structures in the Universe. Gravity has an infnite range, although its eﬀects become increasingly weaker on farther objects.

Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity not as a force, but as a consequence of the curvature of spacetime caused by the uneven distribution of mass. Te most extreme example of this curvature of spacetime is a black hole, from which nothing—not even light—can escape once past the black hole's event horizon. However, for most applications, gravity is well approximated by Newton's law of universal gravitation, which describes gravity as a force which causes any two bodies to be attracted to each other, with the force proportional to the product of their masses and inversely proportional to the square of the distance between them.

Gravity is the weakest of the four fundamental forces of physics, approximately 1038 times weaker than the strong force, 1036 times weaker than the electromagnetic force and 1029 times weaker than the weak force. As a consequence, it has no signifcant infuence at the level of subatomic particles.[2] In contrast, it is the dominant force at the macroscopic scale, and is the cause of the formation, shape and trajectory (orbit) of astronomical bodies. For example, gravity causes the Earth and the other planets to orbit the Sun, it also causes the Moon to orbit the Earth, and causes the formation of tides, the formation and evolution of the Solar System, stars and galaxies.

Te earliest instance of gravity in the Universe, possibly in the form of quantum gravity, supergravity or a gravitational singularity, along with ordinary space and time, developed during the Planck epoch (up to 10−43 seconds after the birth of the Universe), possibly from a primeval state, such as a false vacuum, quantum vacuum or virtual particle, in a currently unknown manner.[3] Attempts to develop a theory of gravity consistent with quantum mechanics, a quantum gravity theory, which would allow gravity to be united in a common mathematical framework (a theory of everything) with the other three forces of physics, are a current area of research.

Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles. Te electromagnetic force usually exhibits electromagnetic felds such as electric

202 felds, magnetic felds and light, and is one of the four fundamental interactions (commonly called forces) in nature. Te other three fundamental interactions are the strong interaction, the weak interaction and gravitation.

Lightning is an electrostatic discharge that travels between two charged regions. Te word electromagnetism is a compound form of two Greek terms, ἤλεκτρον ēlektron, "amber", and μαγνῆτις λίθος magnētis lithos, which means "Μagnesian stone", a type of iron ore. Electromagnetic phenomena are defned in terms of the electromagnetic force, sometimes called the Lorentz force, which includes both electricity and magnetism as diﬀerent manifestations of the same phenomenon.

Te electromagnetic force plays a major role in determining the internal properties of most objects encountered in daily life. Ordinary matter takes its form as a result of intermolecular forces between individual atoms and molecules in matter, and is a manifestation of the electromagnetic force. Electrons are bound by the electromagnetic force to atomic nuclei, and their orbital shapes and their infuence on nearby atoms with their electrons is described by quantum mechanics. Te

5 4 o f 1 1 1 electromagnetic force governs the processes involved in chemistry, which arise from interactions between the electrons of neighboring atoms.

Tere are numerous mathematical descriptions of the electromagnetic feld. In classical electrodynamics, electric felds are described as electric potential and electric current. In Faraday's law, magnetic felds are associated with electromagnetic induction and magnetism, and Maxwell's equations describe how electric and magnetic felds are generated and altered by each other and by charges and currents.

Te theoretical implications of electromagnetism, particularly the establishment of the speed of light based on properties of the "medium" of propagation (permeability and permittivity), led to the development of special relativity by Albert Einstein in 1905.

Although electromagnetism is considered one of the four fundamental forces, at high energy the weak force and electromagnetic force are unifed as a single electroweak force. In the history of the universe, during the quark epoch the unifed force broke into the two separate forces as the universe cooled.

In particle physics, the strong interaction is the mechanism responsible for the strong nuclear force (also called the strong force or nuclear strong force), and is one of the four known fundamental interactions, with the others being electromagnetism, the weak interaction, and gravitation. At the range of 10−15 m (1 femtometer), the strong force is approximately 137 times as strong as electromagnetism, a million times as strong as the weak interaction, and 1038 times as strong as gravitation.[1] Te strong nuclear force holds most ordinary matter together because it confnes quarks into hadron particles such as the proton and neutron. In addition, the strong force binds neutrons and protons to create atomic nuclei. Most of the mass of a common proton or neutron is the result of the strong force feld energy; the individual quarks provide only about 1% of the mass of a proton.

Te strong interaction is observable at two ranges: on a larger scale (about 1 to 3 fm), it is the force that binds protons and neutrons (nucleons) together to form the nucleus of an atom. On the smaller scale (less than about 0.8 fm, the radius of a nucleon), it is the force (carried by gluons) that holds quarks together to form protons, neutrons, and other hadron particles. In the latter context, it is often known as the color force. Te strong force inherently has such a high strength that hadrons bound by the strong force can produce new massive particles. Tus, if hadrons are struck by high-energy particles, they give rise to new hadrons instead of emitting freely moving radiation (gluons). Tis property of the strong force is called color confnement, and it prevents the free "emission" of the strong force: instead, in practice, jets of massive particles are produced.

In the context of binding protons and neutrons together to form atomic nuclei, the strong interaction is called the nuclear force (or residual strong force). In this case, it is the residuum of the strong interaction between the quarks that make up the protons and neutrons. As such, the residual strong interaction obeys a quite different distance-dependent behavior between nucleons, from when it is acting to bind quarks within nucleons. Differences in the binding energy of the nuclear force between different nuclei power nuclear fusion and nuclear fssion. Nuclear fusion accounts for most energy production in the Sun and other stars. Nuclear fssion allows for decay of radioactive elements and isotopes, although it is often mediated by the weak interaction. Artifcially, the energy associated with the nuclear force is partially released in nuclear power and nuclear weapons, both in uranium or plutonium-based fssion weapons and in fusion weapons like the hydrogen bomb.

203 Te strong interaction is mediated by the exchange of massless particles called gluons that act between quarks, antiquarks, and other gluons. Gluons are thought to interact with quarks and other gluons by way of a type of charge called color charge. Color charge is analogous to electromagnetic charge, but it comes in three types (±red, ±green, ±blue) rather than one, which

5 5 o f 1 1 1 results in a diﬀerent type of force, with diﬀerent rules of behavior. Tese rules are detailed in the theory of quantum chromodynamics (QCD), which is the theory of quark-gluon interactions. n particle physics, the weak interaction (the weak force or weak nuclear force) is the mechanism of interaction between subatomic particles that causes radioactive decay and thus plays an essential role in nuclear fssion. Te theory of the weak interaction is sometimes called quantum favourdynamics (QFD), in analogy with the terms quantum chromodynamics (QCD) dealing with the strong interaction and quantum electrodynamics (QED) dealing with the electromagnetic force. However, the term QFD is rarely used because the weak force is best understood in terms of electro-weak theory (EWT).

Te weak interaction takes place only at very small, sub-atomic distances, less than the diameter of a proton. It is one of the four known fundamental interactions of nature, alongside the strong interaction, electromagnetism, and gravitation.

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge. However, in quantum physics, organic chemistry, and biochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions.

In the kinetic theory of gases, the term molecule is often used for any gaseous particle regardless of its composition. According to this defnition, noble gas atoms are considered molecules as they are in fact monoatomic molecules.

A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with oxygen (O2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (H2O). Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are generally not considered single molecules.

Molecules as components of matter are common in organic substances (and therefore biochemistry). Tey also make up most of the oceans and atmosphere. However, the majority of familiar solid substances on Earth, including most of the minerals that make up the crust, mantle, and core of the Earth, contain many chemical bonds, but are not made of identifable molecules. Also, no typical molecule can be defned for ionic crystals (salts) and covalent crystals (network solids), although these are often composed of repeating unit cells that extend either in a plane (such as in graphene) or three- dimensionally (such as in diamond, quartz, or sodium chloride). Te theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules. In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds with no presence of any defnable molecule, nor any of the regularity of repeating units that characterizes crystals.

Magnetism is a class of physical phenomena that are mediated by magnetic felds. Electric currents and the magnetic moments of elementary particles give rise to a magnetic feld, which acts on other currents and magnetic moments. Te most familiar eﬀects occur in ferromagnetic materials, which are strongly attracted by magnetic felds and can be magnetized to become permanent magnets, producing magnetic felds themselves. Only a few substances are ferromagnetic; the most common ones are iron, nickel and cobalt and their alloys. Te prefx ferro- refers to iron, because permanent magnetism was frst observed in lodestone, a form of natural iron ore called magnetite, Fe3O4.

Although ferromagnetism is responsible for most of the eﬀects of magnetism encountered in everyday life, all other materials are infuenced to some extent by a magnetic feld, by several other types of magnetism. Paramagnetic substances such as aluminum and oxygen are weakly attracted to an applied magnetic feld; diamagnetic substances such as copper and carbon are weakly repelled; while antiferromagnetic materials such as chromium and spin glasses have a more 5 6 o f 1 1 1 complex relationship with a magnetic feld. Te force of a magnet on paramagnetic, diamagnetic, antiferromagnetic materials is usually too weak to be felt, and can be detected only by laboratory instruments, so in everyday life these substances are often described as non-magnetic.

Te magnetic state (or magnetic phase) of a material depends on temperature and other variables such as pressure and the applied magnetic feld. A material may exhibit more than one form of magnetism as these variables change.

204 Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles. Te electromagnetic force usually exhibits electromagnetic felds such as electric felds, magnetic felds and light, and is one of the four fundamental interactions (commonly called forces) in nature. Te other three fundamental interactions are the strong interaction, the weak interaction and gravitation.

Lightning is an electrostatic discharge that travels between two charged regions. Te word electromagnetism is a compound form of two Greek terms, ἤλεκτρον ēlektron, "amber", and μαγνῆτις λίθος magnētis lithos,[2] which means "Μagnesian stone",[3] a type of iron ore. Electromagnetic phenomena are defned in terms of the electromagnetic force, sometimes called the Lorentz force, which includes both electricity and magnetism as diﬀerent manifestations of the same phenomenon.

In statistical mechanics, entropy (usual symbol S) is related to the number of microscopic confgurations Ω that a thermodynamic system can have when in a state as specifed by some macroscopic variables. Specifcally, assuming for simplicity that each of the microscopic confgurations is equally probable, the entropy of the system is the natural logarithm of that number of confgurations, multiplied by the Boltzmann constant kB. Formally,

Tis is consistent with 19th-century formulas for entropy in terms of heat and temperature, as discussed below. Boltzmann's constant, and therefore entropy, have dimensions of energy divided by temperature.

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For example, gas in a container with known volume, pressure, and energy could have an enormous number of possible confgurations of the collection of individual gas molecules. At equilibrium, each instantaneous confguration of the gas may be regarded as random. Entropy may be understood as a measure of disorder within a macroscopic system. Te second law of thermodynamics states that an isolated system's entropy never decreases. Such systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy. Non- isolated systems may lose entropy, provided their environment's entropy increases by at least that amount. Since entropy is a function of the state of the system, a change in entropy of a system is determined by its initial and fnal states. Tis applies whether the process is reversible or irreversible. However, irreversible processes increase the combined entropy of the system and its environment.

Entropy is an extensive property. It has the dimension of energy divided by temperature, which has a unit of joules per kelvin (J K−1) in the International System of Units (or kg m2 s−2 K−1 in terms of base units). But the entropy of a pure substance is usually given as an intensive property—either entropy per unit mass (SI unit: J K−1 kg−1) or entropy per unit amount of substance (SI unit: J K−1 mol−1).

Te absolute entropy (S rather than ΔS) was defned later, using either statistical mechanics or the third law of thermodynamics, an otherwise arbitrary additive constant is fxed such that the entropy of a pure substance at absolute zero is zero. In statistical mechanics this refects that the ground state of a system is generally non-degenerate and only one microscopic confguration corresponds to it.

205 In the modern microscopic interpretation of entropy in statistical mechanics, entropy is the amount of additional information needed to specify the exact physical state of a system, given its thermodynamic specifcation. Understanding the role of thermodynamic entropy in various processes requires an understanding of how and why that information changes as the system evolves from its initial to its fnal state. It is often said that entropy is an expression of the disorder, or randomness of a system, or of our lack of information about it. Te second law is now often seen as an expression of the fundamental postulate of statistical mechanics through the modern defnition of entropy.

In physics and mathematics, the dimension of a mathematical space (or object) is informally defned as the minimum number of coordinates needed to specify any point within it. Tus a line has a dimension of one because only one coordinate is needed to specify a point on it – for example, the point at 5 on a number line. A surface such as a plane or the surface of a cylinder or sphere has a dimension of two because two coordinates are needed to specify a point on it – for example, both a latitude and longitude are required to locate a point on the surface of a sphere. Te inside of a cube, a cylinder or a sphere is three-dimensional because three coordinates are needed to locate a point within these spaces.

In classical mechanics, space and time are diﬀerent categories and refer to absolute space and time. Tat conception of the world is a four-dimensional space but not the one that was found necessary to describe electromagnetism. Te four dimensions of spacetime consist of events that are not absolutely defned spatially and temporally, but rather are known relative to the motion of an observer. Minkowski space frst approximates the universe without gravity; the pseudo- Riemannian manifolds of general relativity describe spacetime with matter and gravity. Ten dimensions are used to describe string theory, eleven dimensions can describe supergravity and M-theory, and the state-space of quantum mechanics is an infnite-dimensional function space.

Te concept of dimension is not restricted to physical objects. High-dimensional spaces frequently occur in mathematics and the sciences. Tey may be parameter spaces or confguration spaces such as in Lagrangian or Hamiltonian mechanics; these are abstract spaces, independent of the physical space we live in.

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Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. Te word usually refers to visible light, which is visible to the human eye and is responsible for the sense of sight. Visible light is usually defned as having wavelengths in the range of 400–700 nanometres (nm), or 4.00 × 10−7 to 7.00 × 10−7 m, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). Tis wavelength means a frequency range of roughly 430–750 terahertz (THz).

Te main source of light on Earth is the Sun. Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. Tis process of photosynthesis provides virtually all the energy used by living things. Historically, another important source of light for humans has been fre, from ancient campfres to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has eﬀectively replaced frelight. Some species of animals generate their own light, a process called bioluminescence. For example, frefies use light to locate mates, and vampire squids use it to hide themselves from prey.

Te primary properties of visible light are intensity, propagation direction, frequency or wavelength spectrum, and polarization, while its speed in a vacuum, 299,792,458 metres per second, is one of the fundamental constants of nature. Visible light, as with all types of electromagnetic radiation (EMR), is experimentally found to always move at this speed in a vacuum.

In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. Like all types of light, visible light is emitted and absorbed in tiny "packets" called photons and exhibits properties of both waves and particles. Tis property is referred to as the wave–particle duality. Te study of light, known as optics, is an important research area in modern physics.

Te speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its exact value is 299,792,458 metres per second (approximately 3.00×108 m/s, or 300,000 km/s (186,000 mi/s)). It is exact because the unit of length, the metre, is defned from this constant and the international standard for time. According to special relativity, c is the maximum speed at which all conventional matter and hence all known forms of information in the universe can travel. Tough this speed is most commonly associated with light, it is in fact the speed at which all massless particles and changes of the associated felds travel in vacuum (including electromagnetic radiation and gravitational waves). Such particles and waves travel at c regardless of the motion of the source or the inertial reference frame of the observer. In the theory of relativity, c interrelates space and time, and also appears in the famous equation of mass– energy equivalence E = mc2.

206 Te speed at which light propagates through transparent materials, such as glass or air, is less than c; similarly, the speed of electromagnetic waves in wire cables is slower than c. Te ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200,000 km/s (124,000 mi/s); the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 299,700 km/s (186,220 mi/s) (about 90 km/s (56 mi/s) slower than c).

For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their fnite speed has noticeable eﬀects. In communicating with distant space probes, it can take minutes to hours for a message to get from Earth to the spacecraft, or vice versa. Te light seen from stars left them many years ago, allowing the study of the history of the universe by looking at distant objects. Te fnite speed of light also limits the theoretical maximum speed of computers, since information must be sent within the computer from chip to chip. Te speed of light can be used with time of fight measurements to measure large distances to high precision.

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Ole Rømer frst demonstrated in 1676 that light travels at a fnite speed (as opposed to instantaneously) by studying the apparent motion of Jupiter's moon Io. In 1865, James Clerk Maxwell proposed that light was an electromagnetic wave, and therefore travelled at the speed c appearing in his theory of electromagnetism. In 1905, Albert Einstein postulated that the speed of light c with respect to any inertial frame is a constant and is independent of the motion of the light source. He explored the consequences of that postulate by deriving the theory of relativity and in doing so showed that the parameter c had relevance outside of the context of light and electromagnetism.

After centuries of increasingly precise measurements, in 1975 the speed of light was known to be 299792458 m/s (983571056 ft/s; 186282.397 mi/s) with a measurement uncertainty of 4 parts per billion. In 1983, the metre was redefned in the International System of Units (SI) as the distance travelled by light in vacuum in 1/299792458 of a second. As a result, the numerical value of c in metres per second is now fxed exactly by the defnition of the metre.

Gravity is the weakest of the four fundamental forces of physics, approximately 1038 times weaker than the strong force, 1036 times weaker than the electromagnetic force and 1029 times weaker than the weak force. As a consequence, it has no signifcant infuence at the level of subatomic particles. In contrast, it is the dominant force at the macroscopic scale, and is the cause of the formation, shape and trajectory (orbit) of astronomical bodies. For example, gravity causes the Earth and the other planets to orbit the Sun, it also causes the Moon to orbit the Earth, and causes the formation of tides, the formation and evolution of the Solar System, stars and galaxies.

207 are usually identifable by their geometrical shape, consisting of fat faces with specifc, characteristic orientations. Te scientifc study of

6 0 o f 1 1 1 crystals and crystal formation is known as crystallography. Te process of crystal formation via mechanisms of crystal growth is called crystallization or solidifcation.

Te word crystal derives from the Ancient Greek word κρύσταλλος (krustallos), meaning both "ice" and "rock crystal", [3] from κρύος (kruos), "icy cold, frost".

Examples of large crystals include snowfakes, diamonds, and table salt. Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid. Examples of polycrystals include most metals, rocks, ceramics, and ice. A third category of solids is amorphous solids, where the atoms have no periodic structure whatsoever. Examples of amorphous solids include glass, wax, and many plastics.

Crystals are often used in pseudoscientifc practices such as crystal therapy, and, along with gemstones, are sometimes associated with spellwork in Wiccan beliefs and related religious movements.

In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.

In human physiology and psychology, sound is the reception of such waves and their perception by the brain. Humans can hear sound waves with frequencies between about 20 Hz and 20 kHz. Sound above 20 kHz is ultrasound and below 20 Hz is infrasound. Animals have diﬀerent hearing ranges.

Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the feld of acoustics is an acoustician, while someone working in the feld of acoustical engineering may be called an acoustical engineer. An audio engineer, on the other hand, is concerned with the recording, manipulation, mixing, and reproduction of sound.

Applications of acoustics are found in almost all aspects of modern society, subdisciplines include aeroacoustics, audio signal processing, architectural acoustics, bioacoustics, electro-acoustics, environmental noise, musical acoustics, noise control, psychoacoustics, speech, ultrasound, underwater acoustics, and vibration.

Sound is defned as "(a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sensation evoked by the oscillation described in (a). " Sound can be viewed as a wave motion in air or other elastic media. In this case, sound is a stimulus. Sound can also be viewed as an excitation of the hearing mechanism that results in the perception of sound. In this case, sound is a sensation .

Sound can propagate through a medium such as air, water and solids as longitudinal waves and also as a transverse wave in solids (see Longitudinal and transverse waves, below). Te sound waves are generated by a sound source, such as the vibrating diaphragm of a stereo speaker. Te sound source creates vibrations in the surrounding medium. As the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of sound, thus forming the sound wave. At a fxed distance from the source, the pressure, velocity, and displacement of the medium vary in time. At an instant in time, the pressure, velocity, and displacement vary in space. Note that the particles of the medium do not travel with the sound wave. Tis is intuitively obvious for a solid, and the same is true for liquids and gases (that is, the vibrations of particles in the gas or liquid transport the vibrations, while the average position of the particles over time does not change). During propagation, waves can be refected, refracted, or attenuated by the medium.[5]

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Te behavior of sound propagation is generally aﬀected by three things:

A complex relationship between the density and pressure of the medium. Tis relationship, aﬀected by temperature, determines the speed of sound within the medium. Motion of the medium itself. If the medium is moving, this movement may increase or decrease the absolute speed of the sound wave depending on the direction of the movement. For example, sound moving through wind will have its speed of propagation increased by the speed of the wind if the sound and wind are moving in the same direction. If the sound and wind are moving in opposite directions, the speed of the sound wave will be 208 decreased by the speed of the wind. Te viscosity of the medium. Medium viscosity determines the rate at which sound is attenuated. For many media, such as air or water, attenuation due to viscosity is negligible. When sound is moving through a medium that does not have constant physical properties, it may be refracted (either dispersed or focused).

Spherical compression (longitudinal) waves: Te mechanical vibrations that can be interpreted as sound can travel through all forms of matter: gases, liquids, solids, and plasmas. Te matter that supports the sound is called the medium. Sound cannot travel through a vacuum.

Longitudinal and transverse waves: Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves. It requires a medium to propagate. Trough solids, however, it can be transmitted as both longitudinal waves and transverse waves. Longitudinal sound waves are waves of alternating pressure deviations from the equilibrium pressure, causing local regions of compression and rarefaction, while transverse waves (in solids) are waves of alternating shear stress at right angle to the direction of propagation.

Sound waves may be "viewed" using parabolic mirrors and objects that produce sound.[6]

Te energy carried by an oscillating sound wave converts back and forth between the potential energy of the extra compression (in case of longitudinal waves) or lateral displacement strain (in case of transverse waves) of the matter, and the kinetic energy of the displacement velocity of particles of the medium.

Although there are many complexities relating to the transmission of sounds, at the point of reception (i.e. the ears), sound is readily dividable into two simple elements: pressure and time. Tese fundamental elements form the basis of all sound waves. Tey can be used to describe, in absolute terms, every sound we hear.

However, in order to understand the sound more fully, a complex wave such as this is usually separated into its component parts, which are a combination of various sound wave frequencies (and noise).

Sound waves are often simplifed to a description in terms of sinusoidal plane waves, which are characterized by these generic properties:

Frequency, or its inverse, wavelength Amplitude, sound pressure or Intensity Speed of sound Direction

Sound that is perceptible by humans has frequencies from about 20 Hz to 20,000 Hz. In air at standard temperature and pressure, the corresponding wavelengths of sound waves range from 17 m to 17 mm. Sometimes speed and direction are combined as a velocity vector; wave number and direction are combined as a wave vector. 6 2 o f 1 1 1

Transverse waves, also known as shear waves, have the additional property, polarization, and are not a characteristic of sound waves.

Te speed of sound depends on the medium the waves pass through, and is a fundamental property of the material. Te frst signifcant eﬀort towards measurement of the speed of sound was made by Isaac Newton. He believed the speed of sound in a particular substance was equal to the square root of the pressure acting on it divided by its density.

Tose physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph) using the formula "v = (331 + 0.6 T) m/ s". In fresh water, also at 20 °C, the speed of sound is approximately 1,482 m/s (5,335 km/h; 3,315 mph). In steel, the speed of sound is about 5,960 m/s (21,460 km/h; 13,330 mph). Te speed of sound is also slightly sensitive, being subject to a second-order anharmonic eﬀect, to the sound amplitude, which means there are non-linear propagation eﬀects, such as the production of harmonics and mixed tones not present in the original sound (see parametric array).

Noise is unwanted sound judged to be unpleasant, loud or disruptive to hearing. From a physics standpoint, noise is indistinguishable from sound, as both are vibrations through a medium, such as air or water. Te diﬀerence arises when the brain receives and perceives a sound.

In experimental sciences, noise can refer to any random fuctuations of data that hinders perception of an expected signal.

209 Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast, noise in electronics may not be audible to the human ear and may require instruments for detection.

In audio engineering, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a hiss. Tis signal noise is commonly measured using A-weighting or ITU-R 468 weighting.

Te frst law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems. Te law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed.

It states that the change in the internal energy ΔU of a closed system is equal to the amount of heat Q supplied to the system, minus the amount of work W done by the system on its surroundings. An equivalent statement is that perpetual motion machines of the frst kind are impossible.

Te frst law of thermodynamics for a closed system was expressed in two ways by Clausius. One way referred to cyclic processes and the inputs and outputs of the system, but did not refer to increments in the internal state of the system. Te other way referred to an incremental change in the internal state of the system, and did not expect the process to be cyclic.

A cyclic process is one that can be repeated indefnitely often, returning the system to its initial state. Of particular interest for single cycle of a cyclic process are the net work done, and the net heat taken in (or 'consumed', in Clausius' statement), by the system.

In a cyclic process in which the system does net work on its surroundings, it is observed to be physically necessary not only that heat be taken into the system, but also, importantly, that some 6 3 o f 1 1 1 heat leave the system. Te diﬀerence is the heat converted by the cycle into work. In each repetition of a cyclic process, the net work done by the system, measured in mechanical units, is proportional to the heat consumed, measured in calorimetric units.

Te second law of thermodynamics states that the total entropy can never decrease over time for an isolated system, that is, a system in which neither energy nor matter can enter nor leave. Te total entropy can remain constant in ideal cases where the system is in a steady state (equilibrium), or is undergoing a reversible process. In all other real[according to whom?] cases, the total entropy always increases and the process is irreversible. Te increase in entropy accounts for the irreversibility of natural processes, and the asymmetry between future and past.

Historically, the second law was an empirical fnding that was accepted as an axiom of thermodynamic theory. Statistical thermodynamics, classical or quantum, explains the microscopic origin of the law.

Te second law has been expressed in many ways. Its frst formulation is credited to the French scientist Sadi Carnot, who in 1824 showed that there is an upper limit to the eﬃciency of conversion of heat to work, in a heat engine.

In physics, the terms order and disorder designate the presence or absence of some symmetry or correlation in a many- particle system.

In condensed matter physics, systems typically are ordered at low temperatures; upon heating, they undergo one or several phase transitions into less ordered states. Examples for such an order-disorder transition are: the melting of ice: solid-liquid transition, loss of crystalline order; the demagnetization of iron by heating above the Curie temperature: ferromagnetic-paramagnetic transition, loss of magnetic order. Te degree of freedom that is ordered or disordered can be translational (crystalline ordering), rotational (ferroelectric ordering), or a spin state (magnetic ordering).

Te order can consist either in a full crystalline space group symmetry, or in a correlation. Depending on how the correlations decay with distance, one speaks of long range order or Short range order.

If a disordered state is not in thermodynamic equilibrium, one speaks of quenched disorder. For instance, a glass is obtained by quenching (supercooling) a liquid. By extension, other quenched states are called spin glass, orientational glass. In some contexts, the opposite of quenched disorder is annealed disorder.

210 In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.

Te original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object

Concepts related to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque, which produces changes in rotational speed of an 6 4 o f 1 1 1 object. In an extended body, each part usually applies forces on the adjacent parts; the distribution of such forces through the body is the internal mechanical stress. Such internal mechanical stresses cause no acceleration of that body as the forces balance one another. Pressure, the distribution of many small forces applied over an area of a body, is a simple type of stress that if unbalanced can cause the body to accelerate. Stress usually causes deformation of solid materials, or fow in fuids.

In physics, motion is a change in position of an object over time. Motion is described in terms of displacement, distance, velocity, acceleration, time and speed. Motion of a body is observed by attaching a frame of reference to an observer and measuring the change in position of the body relative to that frame.

If the position of a body is not changing with respect to a given frame of reference, the body is said to be at rest, motionless, immobile, stationary, or to have constant (time-invariant) position. An object's motion cannot change unless it is acted upon by a force, as described. Momentum is a quantity which is used for measuring the motion of an object. An object's momentum is directly related to the object's mass and velocity, and the total momentum of all objects in an isolated system (one not aﬀected by external forces) does not change with time, as described by the law of conservation of momentum.

As there is no absolute frame of reference, absolute motion cannot be determined. Tus, everything in the universe can be considered to be moving.

Motion applies to objects, bodies, and matter particles, to radiation, radiation felds and radiation particles, and to space, its curvature and space-time. One can also speak of motion of shapes and boundaries. So, the term motion, in general, signifes a continuous change in the confguration of a physical system. For example, one can talk about motion of a wave or about motion of a quantum particle, where the confguration consists of probabilities of occupying specifc positions.

In physics, a physical body or physical object (or simply a body or object) is an identifable collection of matter, which may be constrained by an identifable boundary, and may move as a unit by translation or rotation, in 3-dimensional space.

In common usage an object is a collection of matter within a defned contiguous boundary in 3- dimensional space. Te boundary must be defned and identifed by the properties of the material. Te boundary may change over time. Te boundary is usually the visible or tangible surface of the object. Te matter in the object is constrained (to a greater or lesser degree) to move as one object. Te boundary may move in space relative to other objects that it is not attached to (through translation and rotation). An object's boundary may also deform and change over time in other ways.

Also in common usage an object is not constrained to consist of the same collection of matter. Atoms or parts of an object may change over time. An object is defned by the simplest representation of the boundary consistent with the observations. However the laws of Physics only apply directly to objects that consist of the same collection of matter.

Each object has a unique identity, independent of any other properties. Two objects may be identical, in all properties except position, but still remain distinguishable. In most cases the boundaries of two objects may not overlap at any point in time. Te property of identity allows objects to be counted.

Examples of models of physical bodies include, but are not limited to a particle, several interacting smaller bodies (particles or other), and continuous media.

Te common conception of physical objects includes that they have extension in the physical world, although there do exist theories of quantum physics and cosmology which may 6 5 o f 1 1 1

211 challenge[how?] this. In modern physics, "extension" is understood in terms of the spacetime: roughly speaking, it means that for a given moment of time the body has some location in the space, although not necessarily a point. A physical body as a whole is assumed to have such quantitative properties as mass, momentum, electric charge, other conserving quantities, and possibly other quantities.

A body with known composition and described in an adequate physical theory is an example of physical system.

Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied. It also determines the strength of its mutual gravitational attraction to other bodies. Te basic SI unit of mass is the kilogram (kg).

In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less than it does on Earth because of the lower gravity, but it would still have the same mass. Tis is because weight is a force, while mass is the property that (along with gravity) determines the strength of this force.

In Newtonian physics, mass can be generalized as the amount of matter in an object. However, at very high speeds, special relativity states that the kinetic energy of its motion becomes a signifcant additional source of mass. Tus, any stationary body having mass has an equivalent amount of energy, and all forms of energy resist acceleration by a force and have gravitational attraction. In modern physics, matter is not a fundamental concept because its defnition has proven elusive.

Tere are several distinct phenomena which can be used to measure mass. Although some theorists have speculated that some of these phenomena could be independent of each other,[2] current experiments have found no diﬀerence in results regardless of how it is measured:

Inertial mass measures an object's resistance to being accelerated by a force (represented by the relationship F = ma). Active gravitational mass measures the gravitational force exerted by an object. Passive gravitational mass measures the gravitational force exerted on an object in a known gravitational feld.

Te mass of an object determines its acceleration in the presence of an applied force. Te inertia and the inertial mass describe the same properties of physical bodies at the qualitative and quantitative level respectively, by other words, the mass quantitatively describes the inertia. According to Newton's second law of motion, if a body of fxed mass m is subjected to a single force F, its acceleration a is given by F/m. A body's mass also determines the degree to which it generates or is aﬀected by a gravitational feld. If a frst body of mass mA is placed at a distance r (center of mass to center of mass) from a second body of mass mB, each body is subject to an attractive force Fg = GmAmB/r2, where G = 6.67×10−11 N kg−2 m2 is the "universal gravitational constant". Tis is sometimes referred to as gravitational mass.[note 1] Repeated experiments since the 17th century have demonstrated that inertial and gravitational mass are identical; since 1915, this observation has been entailed a priori in the equivalence principle of general relativity.

Te velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specifcation of its speed and direction of motion (e.g. 60 km/h to the north). Velocity is an important concept in kinematics, the branch of classical mechanics that describes the motion of bodies.

Velocity is a physical vector quantity; both magnitude and direction are needed to defne it. Te scalar absolute value (magnitude) of velocity is called "speed", being a coherent derived unit whose quantity is measured in the SI (metric system) as metres per second (m/s) or as the SI base unit of (m⋅s−1). For example, "5 metres per second" is a scalar, whereas "5 metres per second

6 6 o f 1 1 1 east" is a vector. If there is a change in speed, direction or both, then the object has a changing velocity and is said to be undergoing an acceleration.

Acceleration, in physics, is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's Second Law.[1] Te SI unit for acceleration is metre per second squared (m s−2). Accelerations are vector quantities (they have magnitude and direction) and add according to the parallelogram law.[2][3] As a vector, the calculated net force is equal to the product of the object's mass (a scalar quantity) and its acceleration.

212 For example, when a car starts from a standstill (zero relative velocity) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the car turns, an acceleration occurs toward the new direction. In this example, we can call the forward acceleration of the car a "linear acceleration", which passengers in the car might experience as a force pushing them back into their seats. When changing direction, we might call this "non-linear acceleration", which passengers might experience as a sideways force. If the speed of the car decreases, this is an acceleration in the opposite direction from the direction of the vehicle, sometimes called deceleration.[4] Passengers may experience deceleration as a force lifting them forwards. Mathematically, there is no separate formula for deceleration: both are changes in velocity. Each of these accelerations (linear, non-linear, deceleration) might be felt by passengers until their velocity (speed and direction) matches that of the car.

Te newton (symbol: N) is the International System of Units (SI) derived unit of force. It is named after Isaac Newton in recognition of his work on classical mechanics, specifcally Newton's second law of motion.

One newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in direction of the applied force.

In 1946, Conférence Générale des Poids et Mesures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate of 1 metre per second squared. In 1948, the 9th CGPM Resolution 7 adopted the name newton for this force.[1] Te MKS system then became the blueprint for today's SI system of units. Te newton thus became the standard unit of force in the Système international d'unités (SI), or International System of Units.

Tis SI unit is named after Isaac Newton. As with every International System of Units (SI) unit named for a person, the frst letter of its symbol is upper case (N). However, when an SI unit is spelled out in English, it should always begin with a lower case letter (newton)—except in a situation where any word in that position would be capitalized, such as at the beginning of a sentence or in material using title case. Note that "degree Celsius" conforms to this rule because the "d" is lowercase.— Based on Te International System of Units.

Te International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units (ampere, kelvin, second, metre, kilogram, candela, mole) and a set of twenty decimal prefxes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units. Te system also specifes names for 22 derived units for other common physical quantities like lumen, watt, etc.

Te base units, except for one, are derived from invariant constants of nature, such as the speed of light and triple point of water, which can be readily observed and measured with great accuracy. Te kilogram standard of mass is a physical artefact certifed in 1889, consisting of a cylinder of 6 7 o f 1 1 1 platinum-iridium, which ostensibly has the same mass (weight) as one litre of water at the freezing point. Its stability has been a matter of signifcant concern, resulting in recent proposals to change the defnition to one derived from some invariant constant of nature.[1]

Derived units may be defned in terms of base units or other derived units. Tey are adopted to facilitate measurement in diverse felds of endeavor. Te SI is intended to be an evolving system; units and prefxes are created and unit defnitions are modifed through international agreement as the technology of measurement progresses and the precision of measurements improves. Te last new derived unit was defned in 1999.

Te reliability of the SI depends not only on the precise measurement of standards for the base units in terms of various physical constants of nature, but also on precise defnition of those constants. Te set of underlying constants is modifed as more stable constants are found, or other constants may be more precisely measured. For example, in 1983, the metre was redefned to be the distance of light propagation in vacuum in an exact fraction of a second. Tus, the speed of light is now an exactly defned constant of nature.

Te motivation for the development of the SI was the diversity of units that had sprung up within the centimetre–gram– second (CGS) systems (specifcally the inconsistency between the systems of electrostatic units and electromagnetic units) and the lack of coordination between the various disciplines that used them. Te General Conference on Weights and Measures (French: Conférence générale des poids et mesures – CGPM), which was established by the Metre Convention of 1875, brought together many international organisations to establish the defnitions and standards of a new system and standardise the rules for writing and presenting measurements. Te system was published in 1960 as a result of an initiative

213 that began in 1948. It is based on the metre–kilogram–second system of units (MKS) rather than any variant of the CGS. Since then, the SI has been adopted by all developed countries

Electricity is the set of physical phenomena associated with the presence and motion of electric charge. Although initially considered a phenomenon separate from magnetism, since the development of Maxwell's equations, both are recognized as part of a single phenomenon: electromagnetism. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.

Te presence of an electric charge, which can be either positive or negative, produces an electric feld. Te movement of electric charges is an electric current and produces a magnetic feld.

When a charge is placed in a location with a non-zero electric feld, a force will act on it. Te magnitude of this force is given by Coulomb's law. Tus, if that charge were to move, the electric feld would be doing work on the electric charge. Tus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positive charge from an arbitrarily chosen reference point to that point without any acceleration and is typically measured in volts.

Electricity is at the heart of many modern technologies, being used for: electric power where electric current is used to energise equipment; electronics which deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies. Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. Even then, practical applications for electricity were few, and it would not be until the late nineteenth century that electrical engineers were able to put it to industrial and residential use. Te rapid expansion in electrical technology at this time transformed industry and society, becoming a driving force for the 6 8 o f 1 1 1

Second Industrial Revolution. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.

Te presence of charge gives rise to an electrostatic force: charges exert a force on each other, an eﬀect that was known, though not understood, in antiquity. A lightweight ball suspended from a string can be charged by touching it with a glass rod that has itself been charged by rubbing with a cloth. If a similar ball is charged by the same glass rod, it is found to repel the frst: the charge acts to force the two balls apart. Two balls that are charged with a rubbed amber rod also repel each other. However, if one ball is charged by the glass rod, and the other by an amber rod, the two balls are found to attract each other. Tese phenomena were investigated in the late eighteenth century by Charles-Augustin de Coulomb, who deduced that charge manifests itself in two opposing forms. Tis discovery led to the well-known axiom: like-charged objects repel and opposite-charged objects attract.

Te force acts on the charged particles themselves, hence charge has a tendency to spread itself as evenly as possible over a conducting surface. Te magnitude of the electromagnetic force, whether attractive or repulsive, is given by Coulomb's law, which relates the force to the product of the charges and has an inverse-square relation to the distance between them. Te electromagnetic force is very strong, second only in strength to the strong interaction, but unlike that force it operates over all distances. In comparison with the much weaker gravitational force, the electromagnetic force pushing two electrons apart is 1042 times that of the gravitational attraction pulling them together.

Study has shown that the origin of charge is from certain types of subatomic particles which have the property of electric charge. Electric charge gives rise to and interacts with the electromagnetic force, one of the four fundamental forces of nature. Te most familiar carriers of electrical charge are the electron and proton. Experiment has shown charge to be a conserved quantity, that is, the net charge within an electrically isolated system will always remain constant regardless of any changes taking place within that system. Within the system, charge may be transferred between bodies, either by direct contact, or by passing along a conducting material, such as a wire.:2–5 Te informal term static electricity refers to the net presence (or 'imbalance') of charge on a body, usually caused when dissimilar materials are rubbed together, transferring charge from one to the other.

Te charge on electrons and protons is opposite in sign, hence an amount of charge may be expressed as being either negative or positive. By convention, the charge carried by electrons is deemed negative, and that by protons positive, a custom that originated with the work of Benjamin Franklin.[33] Te amount of charge is usually given the symbol Q and expressed in coulombs;[34] each electron carries the same charge of approximately −1.6022×10−19 coulomb. Te proton has

214 a charge that is equal and opposite, and thus +1.6022×10−19 coulomb. Charge is possessed not just by matter, but also by antimatter, each antiparticle bearing an equal and opposite charge to its corresponding particle.

Charge can be measured by a number of means, an early instrument being the gold-leaf electroscope, which although still in use for classroom demonstrations, has been superseded by the electronic electrometer.

Te watt (symbol: W) is a unit of power. In the International System of Units (SI) it is defned as a derived unit of 1 joule per second,[1] and is used to quantify the rate of energy transfer.

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Te volt (symbol: V) is the derived unit for electric potential, electric potential diﬀerence (voltage), and electromotive force. It is named after the Italian physicist Alessandro Volta (1745–1827).

In physics, the kinetic energy of an object is the energy that it possesses due to its motion.[1] It is defned as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. Te same amount of work is done by the body when decelerating from its current speed to a state of rest.

Te standard unit of kinetic energy is the joule.

Te joule (/dʒuːl/); (symbol: J), is a derived unit of energy in the International System of Units.[1] It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N⋅m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).

One joule can also be defned as:

Te work required to move an electric charge of one coulomb through an electrical potential diﬀerence of one volt, or one "coulomb-volt" (C⋅V). Tis relationship can be used to defne the volt. Te work required to produce one watt of power for one second, or one "watt-second" (W⋅s) (compare kilowatt-hour – 3.6 megajoules). Tis relationship can be used to defne the watt.

Although ferromagnetism is responsible for most of the eﬀects of magnetism encountered in everyday life, all other materials are infuenced to some extent by a magnetic feld, by several other types of magnetism. Paramagnetic substances such as aluminum and oxygen are weakly attracted to an applied magnetic feld; diamagnetic substances such as copper and carbon are weakly repelled; while antiferromagnetic materials such as chromium and spin glasses have a more complex relationship with a magnetic feld. Te force of a magnet on paramagnetic, diamagnetic, antiferromagnetic materials is usually too weak to be felt, and can be detected only by laboratory instruments, so in everyday life these substances are often described as non- magnetic.

Te microscopic scale (from Greek: μικρός, mikrós, "small" and σκοπέω, skopéō "look") is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes considered the scale between the macroscopic and the quantum realm. Microscopic units and measurements are used to classify and describe very small objects. One common microscopic length scale unit is the Micrometer (μm) - one millionth of 1 meter.

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215 Te macroscopic scale is the length scale on which objects or phenomena are large enough to be visible almost practically with the naked eye, without magnifying optical instruments.

When applied to physical phenomena and bodies, the macroscopic scale describes things as a person can directly perceive them, without the aid of magnifying devices. Tis is in contrast to observations (microscopy) or theories (microphysics, statistical physics) of objects of geometric lengths smaller than perhaps some hundreds of micrometers.

A macroscopic view of a ball is just that: a ball. A microscopic view could reveal a thick round skin seemingly composed entirely of puckered cracks and fssures (as viewed through a microscope) or, further down in scale, a collection of molecules in a roughly spherical shape. An example of a physical theory that takes a deliberately macroscopic viewpoint is thermodynamics. An example of a topic that extends from macroscopic to microscopic viewpoints is histology.

Not quite by the distinction between macroscopic and microscopic, classical and quantum mechanics are theories that are distinguished in a subtly different way. At frst glance one might think of them as differing simply in the size of objects that they describe, classical objects being considered far larger as to mass and geometrical size than quantal objects, for example a football versus a fne particle of dust. More refned consideration distinguishes classical and quantum mechanics on the basis that classical mechanics fails to recognize that matter and energy cannot be divided into infnitesimally small parcels, so that ultimately fne division reveals irreducibly granular features. Te criterion of fneness is whether or not the interactions are described in terms of Planck's constant. Roughly speaking, classical mechanics considers particles in mathematically idealized terms even as fne as geometrical points with no magnitude, still having their fnite masses. Classical mechanics also considers mathematically idealized extended materials as geometrically continuously substantial. Such idealizations are useful for most everyday calculations, but may fail entirely for molecules, atoms, photons, and other elementary particles. In many ways, classical mechanics can be considered a mainly macroscopic theory. On the much smaller scale of atoms and molecules, classical mechanics may fail, and the interactions of particles are then described by quantum mechanics. Near the absolute minimum of temperature, the Bose–Einstein condensate exhibits effects on macroscopic scale that demand description by quantum mechanics.

Te term "megascopic" is a synonym. No word exists that specifcally refers to features commonly portrayed at reduced scales for better understanding, such as geographic areas or astronomical objects. "Macroscopic" may also refer to a "larger view", namely a view available only from a large perspective. A macroscopic position could be considered the "big picture”.

Particle physics, dealing with the smallest physical systems, is also known as high energy physics. Physics of larger length scales, including the macroscopic scale, is also known as low energy physics. Intuitively, it might seem incorrect to associate "high energy" with the physics of very small, low mass-energy systems, like subatomic particles. By comparison, one gram of hydrogen, a macroscopic system, has ~ 6×1023 times[3] the mass-energy of a single proton, a central object of study in high energy physics. Even an entire beam of protons circulated in the Large Hadron Collider, a high energy physics experiment, contains ~ 3.23×1014 protons,[4] each with 6.5×1012 eV of energy, for a total beam energy of ~ 2.1×1027 eV or ~ 336.4 MJ, which is still ~ 2.7×105 times lower than the mass-energy of a single gram of hydrogen. Yet, the macroscopic realm is "low energy physics", while that of quantum particles is "high energy physics".

Te reason for this is that the "high energy" refers to energy at the quantum particle level. While macroscopic systems indeed have a larger total energy content than any of their constituent quantum particles, there can be no experiment or other observation of this total energy without extracting the respective amount of energy from each of the quantum particles – which is exactly 7 1 o f 1 1 1 the domain of high energy physics. Daily experiences of matter and the Universe are characterized by very low energy. For example, the photon energy of visible light is about 1.8 to 3.2 eV. Similarly, the bond-dissociation energy of a carbon-carbon bond is about 3.6 eV. Tis is the energy scale manifesting at the macroscopic level, such as in chemical reactions. Even photons with far higher energy, gamma rays of the kind produced in radioactive decay, have photon energy that is almost always between 105 eV and 107 eV – still two orders of magnitude lower than the mass-energy of a single proton. Radioactive decay gamma rays are considered as part of nuclear physics, rather than high energy physics.

Finally, when reaching the quantum particle level, the high energy domain is revealed. Te proton has a mass-energy of ~ 9.4×108 eV; some other massive quantum particles, both elementary and hadronic, have yet higher mass-energies. Quantum particles with lower mass-energies are also part of high energy physics; they also have a mass-energy that is far higher than that at the macroscopic scale (such as electrons), or are equally involved in reactions at the particle level (such as neutrinos). Relativistic eﬀects, as in particle accelerators and cosmic rays, can further increase the accelerated particles' energy by many orders of magnitude, as well as the total energy of the particles emanating from their collision and annihilation.

216 Particle physics (also high energy physics) is the branch of physics that studies the nature of the particles that constitute matter and radiation. Although the word "particle" can refer to various types of very small objects (e.g. protons, gas particles, or even household dust), "particle physics" usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour. By our current understanding, these elementary particles are excitations of the quantum felds that also govern their interactions. Te currently dominant theory explaining these fundamental particles and felds, along with their dynamics, is called the Standard Model. Tus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the Higgs boson, or even to the oldest known force feld, gravity.

Teoretical particle physics attempts to develop the models, theoretical framework, and mathematical tools to understand current experiments and make predictions for future experiments. See also theoretical physics. Tere are several major interrelated efforts being made in theoretical particle physics today. One important branch attempts to better understand the Standard Model and its tests. By extracting the parameters of the Standard Model, from experiments with less uncertainty, this work probes the limits of the Standard Model and therefore expands our understanding of nature's building blocks. Tose efforts are made challenging by the difficulty of calculating quantities in quantum chromodynamics. Some theorists working in this area refer to themselves as phenomenologists and they may use the tools of quantum feld theory and effective feld theory. Others make use of lattice feld theory and call themselves lattice theorists.

Another major eﬀort is in model building where model builders develop ideas for what physics may lie beyond the Standard Model (at higher energies or smaller distances). Tis work is often motivated by the hierarchy problem and is constrained by existing experimental data. It may involve work on supersymmetry, alternatives to the Higgs mechanism, extra spatial dimensions (such as the Randall-Sundrum models), Preon theory, combinations of these, or other ideas.

A third major eﬀort in theoretical particle physics is string theory. String theorists attempt to construct a unifed description of quantum mechanics and general relativity by building a theory based on small strings, and branes rather than particles. If the theory is successful, it may be considered a "Teory of Everything", or "TOE".

Tere are also other areas of work in theoretical particle physics ranging from particle cosmology to loop quantum gravity.

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Tis division of eﬀorts in particle physics is refected in the names of categories on the arXiv, a preprint archive:[20] hep-th (theory), hep-ph (phenomenology), hep-ex (experiments), hep-lat (lattice gauge theory).

Particle physics phenomenology is the part of theoretical particle physics that deals with the application of theoretical physics to high-energy experiments. Phenomenology forms a bridge between the mathematical models of theoretical physics (such as quantum feld theories and theories of the structure of space-time) and experimental particle physics, by making quantitative predictions based upon the theoretical models. Phenomenology is related to the philosophical notion in that these predictions describe anticipated behaviors for phenomena in reality.

Te Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions, and not including the gravitational force) in the universe, as well as classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists around the world,[1] with the current formulation being fnalized in the mid-1970s upon experimental confrmation of the existence of quarks. Since then, confrmation of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.

Although the Standard Model is believed to be theoretically self-consistent and has demonstrated huge successes in providing experimental predictions, it leaves some phenomena unexplained and falls short of being a complete theory of fundamental interactions. It does not fully explain baryon asymmetry, incorporate the full theory of gravitation as described by general relativity, or account for the accelerating expansion of the Universe as possibly described by dark energy. Te model does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not incorporate neutrino oscillations and their non-zero masses.

Te development of the Standard Model was driven by theoretical and experimental particle physicists alike. For theorists, the Standard Model is a paradigm of a quantum feld theory, which exhibits a wide range of physics including spontaneous symmetry breaking, anomalies and non- perturbative behavior. It is used as a basis for building more exotic models that incorporate hypothetical particles, extra dimensions, and elaborate symmetries (such as supersymmetry) in an attempt to

217 explain experimental results at variance with the Standard Model, such as the existence of dark matter and neutrino oscillations.

In physics, the fundamental interactions, also known as fundamental forces, are the interactions that do not appear to be reducible to more basic interactions. Tere are four fundamental interactions known to exist: the gravitational and electromagnetic interactions, which produce signifcant long-range forces whose eﬀects can be seen directly in everyday life, and the strong and weak interactions, which produce forces at minuscule, subatomic distances and govern nuclear interactions. Some scientists speculate that a ffth force might exist but if so, it is not widely accepted nor proven.

7 3 o f 1 1 1 atoms, mediating radioactive decay. Te electromagnetic force, carried by the photon, creates electric and magnetic felds, which are responsible for chemical bonding and electromagnetic waves, including visible light, and forms the basis for electrical technology. Although the electromagnetic force is far stronger than gravity, it tends to cancel itself out within large objects, so over the largest distances (on the scale of planets and galaxies), gravity tends to be the dominant force.

A Grand Unifed Teory (GUT) is a model in particle physics in which, at high energy, the three gauge interactions of the Standard Model which defne the electromagnetic, weak, and strong interactions, or forces, are merged into one single force. Tis unifed interaction is characterized by one larger gauge symmetry and thus several force carriers, but one unifed coupling constant. If Grand Unifcation is realized in nature, there is the possibility of a grand unifcation epoch in the early universe in which the fundamental forces are not yet distinct.

Models that do not unify all interactions using one simple group as the gauge symmetry, but do so using semisimple groups, can exhibit similar properties and are sometimes referred to as Grand Unifed Teories as well.

Unifying gravity with the other three interactions would provide a theory of everything (TOE), rather than a GUT. Nevertheless, GUTs are often seen as an intermediate step towards a TOE.

Te novel particles predicted by GUT models are expected to have masses around the GUT scale[clarifcation needed]—just a few orders of magnitude below the Planck scale—and so will be well beyond the reach of any foreseen particle collider experiments. Terefore, the particles predicted by GUT models will be unable to be observed directly and instead the eﬀects of grand unifcation might be detected through indirect observations such as proton decay, electric dipole moments of elementary particles, or the properties of neutrinos. Some GUTs, such as the Pati- Salam model, predict the existence of magnetic monopoles.

GUT models which aim to be completely realistic are quite complicated, even compared to the Standard Model, because they need to introduce additional felds and interactions, or even additional dimensions of space. Te main reason for this complexity lies in the difficulty of reproducing the observed fermion masses and mixing angles which may be related to an existence of some additional family symmetries beyond the conventional GUT models. Due to this difficulty, and due to the lack of any observed effect of grand unifcation so far, there is no generally accepted GUT model.

218 In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one- dimensional objects called strings. It describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the many vibrational states

7 4 o f 1 1 1 of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force. Tus string theory is a theory of quantum gravity.

String theory is a broad and varied subject that attempts to address a number of deep questions of fundamental physics. String theory has been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and condensed matter physics, and it has stimulated a number of major developments in pure mathematics. Because string theory potentially provides a unifed description of gravity and particle physics, it is a candidate for a theory of everything, a self- contained mathematical model that describes all fundamental forces and forms of matter. Despite much work on these problems, it is not known to what extent string theory describes the real world or how much freedom the theory allows in the choice of its details.

String theory was frst studied in the late 1960s as a theory of the strong nuclear force, before being abandoned in favor of quantum chromodynamics. Subsequently, it was realized that the very properties that made string theory unsuitable as a theory of nuclear physics made it a promising candidate for a quantum theory of gravity. Te earliest version of string theory, bosonic string theory, incorporated only the class of particles known as bosons. It later developed into superstring theory, which posits a connection called supersymmetry between bosons and the class of particles called fermions. Five consistent versions of superstring theory were developed before it was conjectured in the mid-1990s that they were all diﬀerent limiting cases of a single theory in eleven dimensions known as M-theory. In late 1997, theorists discovered an important relationship called the AdS/CFT correspondence, which relates string theory to another type of physical theory called a quantum feld theory.

One of the challenges of string theory is that the full theory does not have a satisfactory defnition in all circumstances. Another issue is that the theory is thought to describe an enormous landscape of possible universes, and this has complicated eﬀorts to develop theories of particle physics based on string theory. Tese issues have led some in the community to criticize these approaches to physics and question the value of continued research on string theory unifcation.

Te application of quantum mechanics to physical objects such as the electromagnetic feld, which are extended in space and time, is known as quantum feld theory. In particle physics, quantum feld theories form the basis for our understanding of elementary particles, which are modeled as excitations in the fundamental felds.

In quantum feld theory, one typically computes the probabilities of various physical events using the techniques of perturbation theory. Developed by Richard Feynman and others in the frst half of the twentieth century, perturbative quantum feld theory uses special diagrams called Feynman diagrams to organize computations. One imagines that these diagrams depict the paths of point- like particles and their interactions.

Te starting point for string theory is the idea that the point-like particles of quantum feld theory can also be modeled as one-dimensional objects called strings.. Te interaction of strings is most straightforwardly defned by generalizing the perturbation theory used in ordinary quantum feld theory. At the level of Feynman diagrams, this means replacing the one- dimensional diagram representing the path of a point particle by a two-dimensional surface representing the motion of a string. Unlike in quantum feld theory, string theory does not have a full non-perturbative defnition, so many of the theoretical questions that physicists would like to answer remain out of reach.

In theories of particle physics based on string theory, the characteristic length scale of strings is assumed to be on the order of the Planck length, or 10−35 meters, the scale at which the eﬀects of quantum gravity are believed to become signifcant. On much larger length scales, such as the scales visible in physics laboratories, such objects would be indistinguishable from zero- dimensional point particles, and the vibrational state of the string would determine the type of particle. One of the vibrational states of a string corresponds to the graviton, a quantum mechanical particle that carries the gravitational force.

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Te original version of string theory was bosonic string theory, but this version described only bosons, a class of particles which transmit forces between the matter particles, or fermions. Bosonic string theory was eventually superseded by theories called superstring theories. Tese theories describe both bosons and fermions, and they incorporate a theoretical idea called

219 supersymmetry. Tis is a mathematical relation that exists in certain physical theories between the bosons and fermions. In theories with supersymmetry, each boson has a counterpart which is a fermion, and vice versa.

Tere are several versions of superstring theory: type I, type IIA, type IIB, and two favors of heterotic string theory (SO(32) and E8×E8). Te different theories allow different types of strings, and the particles that arise at low energies exhibit different symmetries. For example, the type I theory includes both open strings (which are segments with endpoints) and closed strings (which form closed loops), while types IIA, IIB and heterotic include only closed strings.

Extra dimensions A tubular surface and corresponding one-dimensional curve. An example of compactifcation: At large distances, a two dimensional surface with one circular dimension looks one- dimensional. In everyday life, there are three familiar dimensions of space: height, width and length. Einstein's general theory of relativity treats time as a dimension on par with the three spatial dimensions; in general relativity, space and time are not modeled as separate entities but are instead unifed to a four-dimensional spacetime. In this framework, the phenomenon of gravity is viewed as a consequence of the geometry of spacetime.

In spite of the fact that the universe is well described by four-dimensional spacetime, there are several reasons why physicists consider theories in other dimensions. In some cases, by modeling spacetime in a diﬀerent number of dimensions, a theory becomes more mathematically tractable, and one can perform calculations and gain general insights more easily.[b] Tere are also situations where theories in two or three spacetime dimensions are useful for describing phenomena in condensed matter physics. Finally, there exist scenarios in which there could actually be more than four dimensions of spacetime which have nonetheless managed to escape detection.

One notable feature of string theories is that these theories require extra dimensions of spacetime for their mathematical consistency. In bosonic string theory, spacetime is 26-dimensional, while in superstring theory it is 10-dimensional, and in M-theory it is 11-dimensional. In order to describe real physical phenomena using string theory, one must therefore imagine scenarios in which these extra dimensions would not be observed in experiments.

Visualization of a complex mathematical surface with many convolutions and self intersections. A cross section of a quintic Calabi–Yau manifold Compactifcation is one way of modifying the number of dimensions in a physical theory. In compactifcation, some of the extra dimensions are assumed to "close up" on themselves to form circles. In the limit where these curled up dimensions become very small, one obtains a theory in which spacetime has eﬀectively a lower number of dimensions. A standard analogy for this is to consider a multidimensional object such as a garden hose. If the hose is viewed from a suﬃcient distance, it appears to have only one dimension, its length. However, as one approaches the hose, one discovers that it contains a second dimension, its circumference. Tus, an ant crawling on the surface of the hose would move in two dimensions.

Compactifcation can be used to construct models in which spacetime is eﬀectively four- dimensional. However, not every way of compactifying the extra dimensions produces a model with the right properties to describe nature. In a viable model of particle physics, the compact extra dimensions must be shaped like a Calabi–Yau manifold.A Calabi–Yau manifold is a special space

7 6 o f 1 1 1 which is typically taken to be six-dimensional in applications to string theory. It is named after mathematicians Eugenio Calabi and Shing-Tung Yau.

Another approach to reducing the number of dimensions is the so-called brane-world scenario. In this approach, physicists assume that the observable universe is a four-dimensional subspace of a higher dimensional space. In such models, the force- carrying bosons of particle physics arise from open strings with endpoints attached to the four-dimensional subspace, while gravity arises from closed strings propagating through the larger ambient space. Tis idea plays an important role in attempts to develop models of real world physics based on string theory, and it provides a natural explanation for the weakness of gravity compared to the other fundamental forces.

Dualities A diagram indicating the relationships between M-theory and the fve superstring theories. A diagram of string theory dualities. Yellow arrows indicate S-duality. Blue arrows indicate T-duality. Main articles: S-duality and T-duality

220 One notable fact about string theory is that the different versions of the theory all turn out to be related in highly nontrivial ways. One of the relationships that can exist between different string theories is called S-duality. Tis is a relationship which says that a collection of strongly interacting particles in one theory can, in some cases, be viewed as a collection of weakly interacting particles in a completely different theory. Roughly speaking, a collection of particles is said to be strongly interacting if they combine and decay often and weakly interacting if they do so infrequently. Type I string theory turns out to be equivalent by S-duality to the SO(32) heterotic string theory. Similarly, type IIB string theory is related to itself in a nontrivial way by S-duality.

Another relationship between diﬀerent string theories is T-duality. Here one considers strings propagating around a circular extra dimension. T-duality states that a string propagating around a circle of radius R is equivalent to a string propagating around a circle of radius 1/R in the sense that all observable quantities in one description are identifed with quantities in the dual description. For example, a string has momentum as it propagates around a circle, and it can also wind around the circle one or more times. Te number of times the string winds around a circle is called the winding number. If a string has momentum p and winding number n in one description, it will have momentum n and winding number p in the dual description. For example, type IIA string theory is equivalent to type IIB string theory via T-duality, and the two versions of heterotic string theory are also related by T-duality.

In general, the term duality refers to a situation where two seemingly different physical systems turn out to be equivalent in a nontrivial way. Two theories related by a duality need not be string theories. For example, Montonen–Olive duality is example of an S-duality relationship between quantum feld theories. Te AdS/CFT correspondence is example of a duality which relates string theory to a quantum feld theory. If two theories are related by a duality, it means that one theory can be transformed in some way so that it ends up looking just like the other theory. Te two theories are then said to be dual to one another under the transformation. Put differently, the two theories are mathematically different descriptions of the same phenomena.

Branes, A pair of surfaces joined by wavy line segments. Open strings attached to a pair of D- branes. In string theory and other related theories, a brane is a physical object that generalizes the notion of a point particle to higher dimensions. For instance, a point particle can be viewed as a brane of dimension zero, while a string can be viewed as a brane of dimension one. It is also possible to consider higher-dimensional branes. In dimension p, these are called p-branes. Te word brane comes from the word "membrane" which refers to a two-dimensional brane.

Branes are dynamical objects which can propagate through spacetime according to the rules of quantum mechanics. Tey have mass and can have other attributes such as charge. A p-brane sweeps out a (p+1)-dimensional volume in spacetime called its worldvolume. Physicists often study felds analogous to the electromagnetic feld which live on the worldvolume of a brane.

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In string theory, D-branes are an important class of branes that arise when one considers open strings. As an open string propagates through spacetime, its endpoints are required to lie on a D- brane. Te letter "D" in D-brane refers to a certain mathematical condition on the system known as the Dirichlet boundary condition. Te study of D-branes in string theory has led to important results such as the AdS/CFT correspondence, which has shed light on many problems in quantum feld theory.

Branes are frequently studied from a purely mathematical point of view, and they are described as objects of certain categories, such as the derived category of coherent sheaves on a complex algebraic variety, or the Fukaya category of a symplectic manifold. Te connection between the physical notion of a brane and the mathematical notion of a category has led to important mathematical insights in the felds of algebraic and symplectic geometry and representation theory.

M-theory Main article: M-theory Prior to 1995, theorists believed that there were fve consistent versions of superstring theory (type I, type IIA, type IIB, and two versions of heterotic string theory). Tis understanding changed in 1995 when Edward Witten suggested that the fve theories were just special limiting cases of an eleven-dimensional theory called M-theory. Witten's conjecture was based on the work of a number of other physicists, including Ashoke Sen, Chris Hull, Paul Townsend, and Michael Duﬀ. His announcement led to a furry of research activity now known as the second superstring revolution.

Unifcation of superstring theories A star-shaped diagram with the various limits of M-theory labeled at its six vertices. A schematic illustration of the relationship between M-theory, the fve superstring theories, and eleven-dimensional

221 supergravity. Te shaded region represents a family of diﬀerent physical scenarios that are possible in M-theory. In certain limiting cases corresponding to the cusps, it is natural to describe the physics using one of the six theories labeled there. In the 1970s, many physicists became interested in supergravity theories, which combine general relativity with supersymmetry. Whereas general relativity makes sense in any number of dimensions, supergravity places an upper limit on the number of dimensions. In 1978, work by Werner Nahm showed that the maximum spacetime dimension in which one can formulate a consistent supersymmetric theory is eleven. In the same year, Eugene Cremmer, Bernard Julia, and Joel Scherk of the École Normale Supérieure showed that supergravity not only permits up to eleven dimensions but is in fact most elegant in this maximal number of dimensions.

Initially, many physicists hoped that by compactifying eleven-dimensional supergravity, it might be possible to construct realistic models of our four-dimensional world. Te hope was that such models would provide a unifed description of the four fundamental forces of nature: electromagnetism, the strong and weak nuclear forces, and gravity. Interest in eleven- dimensional supergravity soon waned as various faws in this scheme were discovered. One of the problems was that the laws of physics appear to distinguish between clockwise and counterclockwise, a phenomenon known as chirality. Edward Witten and others observed this chirality property cannot be readily derived by compactifying from eleven dimensions.

In the frst superstring revolution in 1984, many physicists turned to string theory as a unifed theory of particle physics and quantum gravity. Unlike supergravity theory, string theory was able to accommodate the chirality of the standard model, and it provided a theory of gravity consistent with quantum eﬀects. Another feature of string theory that many physicists were drawn to in the 1980s and 1990s was its high degree of uniqueness. In ordinary particle theories, one can consider any collection of elementary particles whose classical behavior is described by an arbitrary Lagrangian. In string theory, the possibilities are much more constrained: by the 1990s, physicists had argued that there were only fve consistent supersymmetric versions of the theory.

Although there were only a handful of consistent superstring theories, it remained a mystery why there was not just one consistent formulation.[38] However, as physicists began to examine string 7 8 o f 1 1 1 theory more closely, they realized that these theories are related in intricate and nontrivial ways. Tey found that a system of strongly interacting strings can, in some cases, be viewed as a system of weakly interacting strings. Tis phenomenon is known as S-duality. It was studied by Ashoke Sen in the context of heterotic strings in four dimensions and by Chris Hull and Paul Townsend in the context of the type IIB theory. Teorists also found that diﬀerent string theories may be related by T-duality. Tis duality implies that strings propagating on completely diﬀerent spacetime geometries may be physically equivalent.

At around the same time, as many physicists were studying the properties of strings, a small group of physicists was examining the possible applications of higher dimensional objects. In 1987, Eric Bergshoeff, Ergin Sezgin, and Paul Townsend showed that eleven-dimensional supergravity includes two-dimensional branes. Intuitively, these objects look like sheets or membranes propagating through the eleven-dimensional spacetime. Shortly after this discovery, Michael Duff, Paul Howe, Takeo Inami, and Kellogg Stelle considered a particular compactifcation of eleven- dimensional supergravity with one of the dimensions curled up into a circle. In this setting, one can imagine the membrane wrapping around the circular dimension. If the radius of the circle is sufficiently small, then this membrane looks just like a string in ten-dimensional spacetime. In fact, Duff and his collaborators showed that this construction reproduces exactly the strings appearing in type IIA superstring theory.

Speaking at a string theory conference in 1995, Edward Witten made the surprising suggestion that all fve superstring theories were in fact just diﬀerent limiting cases of a single theory in eleven spacetime dimensions. Witten's announcement drew together all of the previous results on S- and T-duality and the appearance of higher dimensional branes in string theory. In the months following Witten's announcement, hundreds of new papers appeared on the Internet confrming diﬀerent parts of his proposal. Today this furry of work is known as the second superstring revolution.

Initially, some physicists suggested that the new theory was a fundamental theory of membranes, but Witten was skeptical of the role of membranes in the theory. In a paper from 1996, Hořava and Witten wrote "As it has been proposed that the eleven-dimensional theory is a supermembrane theory but there are some reasons to doubt that interpretation, we will non- committally call it the M- theory, leaving to the future the relation of M to membranes.” In the absence of an understanding of the true meaning and structure of M-theory, Witten has suggested that the M should stand for "magic", "mystery", or "membrane" according to taste, and the true meaning of the title should be decided when a more fundamental formulation of the theory is known.

Matrix theory Main article: Matrix theory (physics) 222 In mathematics, a matrix is a rectangular array of numbers or other data. In physics, a matrix model is a particular kind of physical theory whose mathematical formulation involves the notion of a matrix in an important way. A matrix model describes the behavior of a set of matrices within the framework of quantum mechanics.

One important example of a matrix model is the BFSS matrix model proposed by Tom Banks, Willy Fischler, Stephen Shenker, and Leonard Susskind in 1997. Tis theory describes the behavior of a set of nine large matrices. In their original paper, these authors showed, among other things, that the low energy limit of this matrix model is described by eleven- dimensional supergravity. Tese calculations led them to propose that the BFSS matrix model is exactly equivalent to M- theory. Te BFSS matrix model can therefore be used as a prototype for a correct formulation of M-theory and a tool for investigating the properties of M-theory in a relatively simple setting.

Te development of the matrix model formulation of M-theory has led physicists to consider various connections between string theory and a branch of mathematics called noncommutative geometry. Tis subject is a generalization of ordinary geometry in which mathematicians defne new geometric notions using tools from noncommutative algebra. In a paper from 1998, Alain Connes, Michael R. Douglas, and Albert Schwarz showed that some aspects of matrix models and 7 9 o f 1 1 1

M-theory are described by a noncommutative quantum feld theory, a special kind of physical theory in which spacetime is described mathematically using noncommutative geometry. Tis established a link between matrix models and M-theory on the one hand, and noncommutative geometry on the other hand. It quickly led to the discovery of other important links between noncommutative geometry and various physical theories.

Quantum gravity (QG) is a feld of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics, and where quantum eﬀects cannot be ignored, such as near compact astrophysical objects where the eﬀects of gravity are strong.

Te current understanding of gravity is based on Albert Einstein's general theory of relativity, which is formulated within the framework of classical physics. On the other hand, the other three fundamental forces of physics are described within the framework of quantum mechanics and quantum feld theory, radically diﬀerent formalisms for describing physical phenomena. It is sometimes argued that a quantum mechanical description of gravity is necessary on the grounds that one cannot consistently couple a classical system to a quantum one. However, Robert Wald appeared to refute that by providing an explicit construction of a consistent semiclassical theory.

While a quantum theory of gravity may be needed in order to reconcile general relativity with the principles of quantum mechanics, diﬃculties arise when one attempts to apply the usual prescriptions of quantum feld theory to the force of gravity via graviton bosons. Te problem is that the theory one gets in this way is not renormalizable and therefore cannot be used to make meaningful physical predictions. As a result, theorists have taken up more radical approaches to the problem of quantum gravity, the most popular approaches being string theory and loop quantum gravity.

Strictly speaking, the aim of quantum gravity is only to describe the quantum behavior of the gravitational feld and should not be confused with the objective of unifying all fundamental interactions into a single mathematical framework. While any substantial improvement into the present understanding of gravity would aid further work towards unifcation, study of quantum gravity is a feld in its own right with various branches having diﬀerent approaches to unifcation. Although some quantum gravity theories, such as string theory, try to unify gravity with the other fundamental forces, others, such as loop quantum gravity, make no such attempt; instead, they make an eﬀort to quantize the gravitational feld while it is kept separate from the other forces. A theory of quantum gravity that is also a grand unifcation of all known interactions is sometimes referred to as Te Teory of Everything (TOE).

One of the difficulties of quantum gravity is that quantum gravitational effects are only expected to become apparent near the Planck scale, a scale far smaller in distance (equivalently, far larger in energy) than those currently accessible at high energy particle accelerators. As a result, quantum gravity is a mainly theoretical enterprise, although there are speculations about how quantum gravitational effects might be observed in existing experiments.

Teoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. Tis is in contrast to experimental physics, which uses experimental tools to probe these phenomena.

Te advancement of science generally depends on the interplay between experimental studies and theory. In some cases, theoretical physics adheres to standards of mathematical rigor while giving little weight to experiments and observations.[a] For example, while developing special relativity, Albert Einstein was concerned with the Lorentz transformation which left Maxwell's equations invariant, but was apparently uninterested in the Michelson–Morley experiment on Earth's drift

223 through a luminiferous ether.[citation needed] Conversely, Einstein was awarded the Nobel Prize for explaining the photoelectric eﬀect, previously an experimental result lacking a theoretical formulation.

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Te photoelectric eﬀect is the emission of electrons or other free carriers when light shines on a material. Electrons emitted in this manner can be called photo electrons. Tis phenomenon is commonly studied in electronic physics, as well as in felds of chemistry, such as quantum chemistry or electrochemistry.

According to classical electromagnetic theory, this eﬀect can be attributed to the transfer of energy from the light to an electron. From this perspective, an alteration in the intensity of light would induce changes in the kinetic energy of the electrons emitted from the metal. Furthermore, according to this theory, a suﬃciently dim light would be expected to show a time lag between the initial shining of its light and the subsequent emission of an electron. However, the experimental results did not correlate with either of the two predictions made by classical theory.

Instead, electrons are dislodged only by the impingement of photons when those photons reach or exceed a threshold frequency (energy). Below that threshold, no electrons are emitted from the material regardless of the light intensity or the length of time of exposure to the light (rarely, an electron will escape by absorbing two or more quanta. However, this is extremely rare because by the time it absorbs enough quanta to escape, the electron will probably have emitted the rest of the quanta.). To make sense of the fact that light can eject electrons even if its intensity is low, Albert Einstein proposed that a beam of light is not a wave propagating through space, but rather a collection of discrete wave packets (photons), each with energy hν. Tis shed light on Max Planck's previous discovery of the Planck relation (E = hν) linking energy (E) and frequency (ν) as arising from quantization of energy. Te factor h is known as the Planck constant.

In 1887, Heinrich Hertz discovered that electrodes illuminated with ultraviolet light create electric sparks more easily. In 1900, while studying black-body radiation, the German physicist Max Planck suggested that the energy carried by electromagnetic waves could only be released in "packets" of energy. In 1905, Albert Einstein published a paper advancing the hypothesis that light energy is carried in discrete quantized packets to explain experimental data from the photoelectric effect. Tis model contributed to the development of quantum mechanics. In 1914, Robert Millikan's experiment supported Einstein's model of the photoelectric effect. Einstein was awarded the Nobel Prize in 1921 for "his discovery of the law of the photoelectric effect", and Millikan was awarded the Nobel Prize in 1923 for "his work on the elementary charge of electricity and on the photoelectric effect".

Te photoelectric effect requires photons with energies approaching zero (in the case of negative electron affinity) to over 1 MeV for core electrons in elements with a high atomic number. Emission of conduction electrons from typical metals usually requires a few electron-volts, corresponding to short-wavelength visible or ultraviolet light. Study of the photoelectric effect led to important steps in understanding the quantum nature of light and electrons and infuenced the formation of the concept of wave–particle duality. Other phenomena where light affects the movement of electric charges include the photoconductive effect (also known as photoconductivity or photoresistivity), the photovoltaic effect, and the photoelectrochemical effect.

Photoemission can occur from any material, but it is most easily observable from metals or other conductors because the process produces a charge imbalance, and if this charge imbalance is not neutralized by current fow (enabled by conductivity), the potential barrier to emission increases until the emission current ceases. It is also usual to have the emitting surface in a vacuum, since gases impede the fow of photoelectrons and make them diﬃcult to observe. Additionally, the energy barrier to photoemission is usually increased by thin oxide layers on metal surfaces if the metal has been exposed to oxygen, so most practical experiments and devices based on the photoelectric eﬀect use clean metal surfaces in a vacuum.

When the photoelectron is emitted into a solid rather than into a vacuum, the term internal photoemission is often used, and emission into a vacuum distinguished as external photoemission.

8 1 o f 1 1 1

A spectrum (plural spectra or spectrums)[1] is a condition that is not limited to a specifc set of values but can vary, without steps, across a continuum. Te word was frst used scientifcally in optics to describe the rainbow of colors in visible light after passing through a prism. As scientifc understanding of light advanced, it came to apply to the entire electromagnetic spectrum.

224 Spectrum has since been applied by analogy to topics outside optics. Tus, one might talk about the "spectrum of political opinion", or the "spectrum of activity" of a drug, or the "autism spectrum". In these uses, values within a spectrum may not be associated with precisely quantifable numbers or defnitions. Such uses imply a broad range of conditions or behaviors grouped together and studied under a single title for ease of discussion. Nonscientifc uses of the term spectrum are sometimes misleading. For instance, a single left–right spectrum of political opinion does not capture the full range of people's political beliefs. Political scientists use a variety of biaxial and multiaxial systems to more accurately characterize political opinion.

In most modern usages of spectrum there is a unifying theme between the extremes at either end. Tis was not always true in older usage.

Optics is the branch of physics which involves the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it.[1] Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.[1]

Most optical phenomena can be accounted for using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplifed models. Te most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or refect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics. Historically, the ray-based model of light was developed frst, followed by the wave model of light. Progress in electromagnetic theory in the 19th century led to the discovery that light waves were in fact electromagnetic radiation.

Some phenomena depend on the fact that light has both wave-like and particle-like properties. Explanation of these eﬀects requires quantum mechanics. When considering light's particle-like properties, the light is modelled as a collection of particles called "photons". Quantum optics deals with the application of quantum mechanics to optical systems.

Optical science is relevant to and studied in many related disciplines including astronomy, various engineering felds, photography, and medicine (particularly ophthalmology and optometry). Practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, lenses, telescopes, microscopes, lasers, and fbre optics. ight is electromagnetic radiation within a certain portion of the electromagnetic spectrum. Te word usually refers to visible light, which is the visible spectrum that is visible to the human eye and is responsible for the sense of sight.[1] Visible light is usually defned as having wavelengths in the range of 400–700 nanometres (nm), or 4.00 × 10−7 to 7.00 × 10−7 m, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).[2][3] Tis wavelength means a frequency range of roughly 430–750 terahertz (THz).

Te electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.

Te electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. Tis frequency range is divided into separate bands, 8 2 o f 1 1 1 and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, terahertz waves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. Te electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. Te limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length.[4] Gamma rays, X- rays, and high ultraviolet are classifed as ionizing radiation as their photons have enough energy to ionize atoms, causing chemical reactions. Exposure to these rays can be a health hazard, causing radiation sickness, DNA damage and cancer. Radiation of visible light wavelengths and lower are called nonionizing radiation as they cannot cause these effects.

In most of the frequency bands above, a technique called spectroscopy can be used to physically separate waves of diﬀerent frequencies, producing a spectrum showing the constituent frequencies. Spectroscopy is used to study the interactions of electromagnetic waves with matter. [5] Other technological uses are described under electromagnetic radiation.

225 Black-body radiation is the thermal electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non- refective body). It has a specifc spectrum and intensity that depends only on the body's temperature, which is assumed for the sake of calculations and theory to be uniform and constant. [1][2][3][4]

Te thermal radiation spontaneously emitted by many ordinary objects can be approximated as black-body radiation. A perfectly insulated enclosure that is in thermal equilibrium internally contains black-body radiation and will emit it through a hole made in its wall, provided the hole is small enough to have negligible eﬀect upon the equilibrium.

A black-body at room temperature appears black, as most of the energy it radiates is infra-red and cannot be perceived by the human eye. Because the human eye cannot perceive light waves at lower frequencies, a black body, viewed in the dark at the lowest just faintly visible temperature, subjectively appears grey, even though its objective physical spectrum peak is in the infrared range.[5] When it becomes a little hotter, it appears dull red. As its temperature increases further it becomes yellow, white, and ultimately blue-white.

Although planets and stars are neither in thermal equilibrium with their surroundings nor perfect black bodies, black-body radiation is used as a frst approximation for the energy they emit.[6] Black holes are near-perfect black bodies, in the sense that they absorb all the radiation that falls on them. It has been proposed that they emit black-body radiation (called Hawking radiation), with a temperature that depends on the mass of the black hole.[7]

Te term black body was introduced by Gustav Kirchhoﬀ in 1860.[8] Black-body radiation is also called thermal radiation, cavity radiation, complete radiation or temperature radiation. frequency Common symbols f, ν SI unit Hz In SI base units s−1 Frequency is the number of occurrences of a repeating event per unit of time.[1] It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. Te period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency.[2] For example, if a newborn baby's heart beats at a frequency of 120 times a minute, its period—the time interval between beats—is half a second (that is, 60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to 8 3 o f 1 1 1 specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light.

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies as high as 300 gigahertz (GHz) to as low as 30 hertz (Hz).[1] At 300 GHz, the corresponding wavelength is 1 mm, and at 30 Hz is 10,000 km. Like all other electromagnetic waves, radio waves travel at the speed of light. Tey are generated by electric charges undergoing acceleration, such as time varying electric currents.[2] Naturally occurring radio waves are emitted by lightning and astronomical objects.

Radio waves are generated artifcially by transmitters and received by radio receivers, using antennas. Radio waves are very widely used in modern technology for fxed and mobile radio communication, broadcasting, radar and other navigation systems, communications satellites, wireless computer networks and many other applications. Different frequencies of radio waves have different propagation characteristics in the Earth's atmosphere; long waves can diffract around obstacles like mountains and follow the contour of the earth (ground waves), shorter waves can refect off the ionosphere and return to earth beyond the horizon (skywaves), while much shorter wavelengths bend or diffract very little and travel on a line of sight, so their propagation distances are limited to the visual horizon.

To prevent interference between diﬀerent users, the artifcial generation and use of radio waves is strictly regulated by law, coordinated by an international body called the International Telecommunications Union (ITU), which defnes radio waves as "electromagnetic waves of frequencies arbitrarily lower than 3 000 GHz, propagated in space without artifcial guide".[3] Te radio spectrum is divided into a number of radio bands on the basis of frequency, allocated to diﬀerent uses.

An audio signal is a representation of sound, typically as an electrical voltage for analog signals and a binary number for digital signals. Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz (the limits of human hearing). Audio signals may be synthesized directly, or may originate at a transducer such as a microphone, musical 226 instrument pickup, phonograph cartridge, or tape head. Loudspeakers or headphones convert an electrical audio signal into sound.

Digital audio systems represent audio signals in a variety of digital formats.[1]

An audio channel or audio track is an audio signal communications channel in a storage device or mixing console, used in operations such as multi-track recording and sound reinforcement.

Signal fow is the path an audio signal will take from source to the speaker or recording device. Signal fow may be short and simple as in a home audio system or long and convoluted in a recording studio and larger sound reinforcement system as the signal may pass through many sections of a large console, external audio equipment, and even diﬀerent rooms.

Audio signals may be characterized by parameters such as their bandwidth, nominal level, power level in decibels (dB), and voltage level. Te relation between power and voltage is determined by the impedance of the signal path, which may be single-ended or balanced.

Audio signals have somewhat standardized levels depending on application. Outputs of professional mixing consoles are most commonly at line level. Consumer audio equipment will also output at a lower line level. Microphones generally output at an even lower level, commonly referred to a mic level.

As much of the older analog audio equipment has been emulated in digital form, usually through the development of audio plug-ins for digital audio workstation (DAW) software, the path of digital

8 4 o f 1 1 1 information through the DAW (i.e. from an audio track through a plug-in and out a hardware output) is also called an audio signal or signal fow.[citation needed]

A digital audio signal being sent through wire can use several formats including optical (ADAT, TDIF), coaxial (S/PDIF), XLR (AES/EBU), and Ethernet.

Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli Fantina, Sicily Te main source of light on Earth is the Sun. Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. Tis process of photosynthesis provides virtually all the energy used by living things. Historically, another important source of light for humans has been fre, from ancient campfres to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has eﬀectively replaced frelight. Some species of animals generate their own light, a process called bioluminescence. For example, frefies use light to locate mates, and vampire squids use it to hide themselves from prey.

In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not.[5][6] In this sense, gamma rays, X-rays, microwaves and radio waves are also light. Like all types of EM radiation, visible light propagates as waves. However, the energy imparted by the waves is absorbed at single locations the way particles are absorbed. Te absorbed energy of the EM waves is called a photon, and represents the quanta of light. When a wave of light is transformed and absorbed as a photon, the energy of the wave instantly collapses to a single location, and this location is where the photon "arrives." Tis is what is called the wave function collapse. Tis dual wave-like and particle-like nature of light is known as the wave–particle duality. Te study of light, known as optics, is an important research area in modern physics.

Darkness, the polar opposite to brightness, is understood as a lack of illumination or an absence of visible light.

Human vision is unable to distinguish color in conditions of either high brightness or darkness.[1] In conditions with insuﬃcient light levels, color perception ranges from achromatic to ultimately black.

Te emotional response to darkness has generated metaphorical usages of the term in many cultures.

227 Referring to a time of day, complete darkness occurs when the Sun is more than 18° below the horizon, without the eﬀects of twilight on the night sky.

Perception

Te perception of darkness diﬀers from the mere absence of light due to the eﬀects of after images on perception. In perceiving, the eye is active, and the part of the retina that is unstimulated produces a complementary afterimage.[2]

Physics In terms of physics, an object is said to be dark when it absorbs photons, causing it to appear dim compared to other objects. For example, matte black paint does not refect much visible light and appears dark, whereas white paint refects lots of light and appears bright.[3] For more information see color. An object may appear dark, but it may be bright at a frequency that humans cannot perceive. 8 5 o f 1 1 1

A dark area has limited light sources, making things hard to see. Exposure to alternating light and darkness (night and day) has caused several evolutionary adaptations to darkness. When a vertebrate, like a human, enters a dark area, its pupils dilate, allowing more light to enter the eye and improving night vision. Also, the light detecting cells in the human eye (rods and cones) will regenerate more unbleached rhodopsin when adapting to darkness.

One scientifc measure of darkness is the Bortle Dark-Sky Scale, which indicates the night sky's and stars' brightness at a particular location, and the observability of celestial objects at that location. (See also: Sky brightness)

Technical Te color of a point, on a standard 24-bit computer display, is defned by three RGB (red, green, blue) values, each ranging from 0-255. When the red, green, and blue components of a pixel are fully illuminated (255,255,255), the pixel appears white; when all three components are unilluminated (0,0,0), the pixel appears black.

Math

Mathematics (from Greek μάθημα máthēma, "knowledge, study, learning") is the study of topics such as quantity (numbers), structure, space, change and statistics. Tere are many views among mathematicians and philosophers as to the exact scope and defnition of mathematics.

Mathematicians seek out patterns and use them to formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proof. When mathematical structures are good models of real phenomena, then mathematical 228 reasoning can provide insight or predictions about nature. Trough the use of abstraction and logic, mathematics developed from counting, calculation, measurement, and the systematic study of the shapes and motions of physical objects.

In mathematics, a structure on a set is an additional mathematical object that, in some manner, attaches (or relates) to that set to endow it with some additional meaning or signifcance.

A number is a mathematical object used to count, measure and also label. Te original examples are the natural numbers 1, 2, 3, 4 and so forth.[1] A notational symbol that represents a number is called a numeral.[2] In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, number may refer to a symbol, a word, or a mathematical abstraction.

In mathematics, the notion of number has been extended over the centuries to include 0,[3] negative numbers,[4] rational numbers such as 1 / 2 and −2/3 , real numbers[5] such as √2 and π, and complex numbers,[6] which extend the real numbers by adding a square root of −1. [4] Calculations with numbers are done with arithmetical operations, the most familiar being addition, subtraction, multiplication, division, and exponentiation. Teir study or usage is called arithmetic. Te same term may also refer to number theory, the study of the properties of numbers.

Besides their practical uses, numbers have cultural signifcance throughout the world.[7][8] For example, in Western society, the number 13 is regarded as unlucky, and "a million" may signify "a lot."[7] Tough it is now regarded as pseudoscience, numerology, the belief in a mystical signifcance of numbers, permeated ancient and medieval thought.[9] Numerology heavily infuenced the development of Greek mathematics, stimulating the investigation of many problems in number theory which are still of interest today.[9]

During the 19th century, mathematicians began to develop many diﬀerent abstractions which share certain properties of numbers and may be seen as extending the concept. Among the frst were the hypercomplex numbers, which consist of various extensions or modifcations of the complex number system. Today, number systems are considered important special examples of much more general categories such as rings and felds, and the application of the term "number" is a matter of convention, without fundamental signifcance.[10]

A partial list of possible structures are measures, algebraic structures (groups, felds, etc.), topologies, metric structures (geometries), orders, events, equivalence relations, diﬀerential structures, and categories.

Arithmetic (from the Greek ἀριθμός arithmos, "number") is a branch of mathematics that consists of the study of numbers, especially the properties of the traditional operations on them—addition, subtraction, multiplication and division. Arithmetic is an elementary part of number theory, and number theory is considered to be one of the top-level divisions of modern mathematics, along with algebra, geometry, and analysis. Te terms arithmetic and higher arithmetic were used until the beginning of the 20th century as synonyms for number theory and are sometimes still used to refer to a wider part of number theory.

Mathematical symbols are used in all branches of mathematics to express a formula or to represent a constant. A mathematical concept is independent of the symbol chosen to represent it. For many of the symbols below, the symbol is usually synonymous with the corresponding concept (ultimately an arbitrary choice made as a result of the cumulative history of mathematics), but in some situations, a diﬀerent convention may be used. For example, depending on context, the triple bar "≡" may represent congruence or a defnition. However, in mathematical logic, numerical equality is sometimes represented by "≡" instead of "=", with the latter representing equality of well-formed formulas. In short, convention dictates the meaning.

Te plus and minus signs (+ and −) are mathematical symbols used to represent the notions of positive and negative as well as the operations of addition and subtraction. Teir use has been extended to many other meanings, more or less analogous. Plus and minus are Latin terms meaning "more" and "less", respectively.

Multiplication (often denoted by the cross symbol "×", by a point "⋅", by juxtaposition, or, on computers, by an asterisk "∗") is one of the four elementary mathematical operations of arithmetic; with the others being addition, subtraction and division.

229 Te multiplication of whole numbers may be thought as a repeated addition; that is, the multiplication of two numbers is equivalent to adding as many copies of one of them, the multiplicand, as the value of the other one, the multiplier. Normally, the multiplier is written frst and multiplicand second,[1] (though this can vary by language.)

Division is one of the four basic operations of arithmetic, the others being addition, subtraction, and multiplication. Te division of two natural numbers is the process of calculating the number of times one number is contained within another one.:7 For example, in the picture on the right, the 20 apples are divided into groups of fve apples, and there exist four groups, meaning that fve can be contained within 20 four times, or 20 ÷ 5 = 4. Division can also be thought of as the process of evaluating a fraction, and fractional notation (a/b and a⁄b) is commonly used to represent division.

Division can be viewed either as quotition or as partition. In quotition, 20 ÷ 5 means the number of 5s that must be added to get 20. In partition, 20 ÷ 5 means the size of each of 5 parts into which a set of size 20 is divided.

Division is the inverse of multiplication; if a × b = c, then a = c ÷ b, as long as b is not zero. Division by zero is undefned for the real numbers and most other contexts,:246 because if b = 0, then a cannot be deduced from b and c, as then c will always equal zero regardless of a. In some contexts, division by zero can be defned although to a limited extent, and limits involving division of a real number as it approaches zero are defned.[a]

In division, the dividend is divided by the divisor to get a quotient. In the above example, 20 is the dividend, fve is the divisor, and four is the quotient. In some cases, the divisor may not be contained fully by the dividend; for example, 10 ÷ 3 leaves a remainder of one, as 10 is not a multiple of three. Sometimes this remainder is added to the quotient as a fractional part, so 10 ÷ 3 is equal to 3 1/3 or 3.33 . . ., but in the context of integer division, where numbers have no fractional part, the remainder is kept separately or discarded.

Besides dividing apples, division can be applied to other physical and abstract objects. Division has been defned in several contexts, such as for the real and complex numbers and for more abstract contexts such as for vector spaces and felds.

Division is the most mentally diﬃcult of the four basic operations of arithmetic[citation needed], but the discipline and mastery of it provides an educational bridge from arithmetic to number theory and algebra. Teaching the objective concept of dividing integers introduces students to the arithmetic of fractions. Unlike addition, subtraction, and multiplication, the set of all integers is not closed under division. Dividing two integers may result in a remainder. To complete the division of the remainder, the number system is extended to include fractions or rational numbers as they are more generally called. When students advance to algebra, the abstract theory of division intuited from arithmetic naturally extends to algebraic division of variables, polynomials, and matrices.

Sometimes, a set is endowed with more than one structure simultaneously; this enables mathematicians to study it more richly. For example, an ordering imposes a rigid form, shape, or topology on the set. As another example, if a set has both a topology and is a group, and these two structures are related in a certain way, the set becomes a topological group.

Mappings between sets which preserve structures (so that structures in the source or domain are mapped to equivalent structures in the destination or codomain) are of special interest in many felds of mathematics. Examples are homomorphisms, which preserve algebraic structures; 8 7 o f 1 1 1 homeomorphisms, which preserve topological structures; and diﬀeomorphisms, which preserve diﬀerential structures.

Infnity (symbol: ∞) is a concept describing something without any bound or larger than any natural number. Philosophers have speculated about the nature of the infnite, for example Zeno of Elea, who proposed many paradoxes involving infnity, and Eudoxus of Cnidus, who used the idea of infnitely small quantities in his method of exhaustion. Modern mathematics uses the general concept of infnity in the solution of many practical and theoretical problems, such as in calculus and set theory, and the idea also is used in physics and the other sciences.

In mathematics, "infnity" is often treated as a number (i.e., it counts or measures things: "an infnite number of terms") but it is not the same sort of number as either a natural or a real number.

230 Georg Cantor formalized many ideas related to infnity and infnite sets during the late 19th and early 20th centuries. In the theory he developed, there are infnite sets of diﬀerent sizes (called cardinalities). For example, the set of integers is countably infnite, while the infnite set of real numbers is uncountable.

Nano- (symbol n) is a unit prefx meaning "one billionth". Used primarily with the metric system, this prefx denotes a factor of 10−9 or 0.000000001. It is frequently encountered in science and electronics for prefxing units of time and length. Geometry (from the Ancient Greek: γεωμετρία; geo- "earth", -metron "measurement") is a branch of mathematics concerned with questions of shape, size, relative position of fgures, and the properties of space. A mathematician who works in the feld of geometry is called a geometer.

Geometry arose independently in a number of early cultures as a practical way for dealing with lengths, areas, and volumes. Geometry began to see elements of formal mathematical science emerging in the West as early as the 6th century BC. By the 3rd century BC, geometry was put into an axiomatic form by Euclid, whose treatment, Euclid's Elements, set a standard for many centuries to follow. Geometry arose independently in India, with texts providing rules for geometric constructions appearing as early as the 3rd century BC.Islamic scientists preserved Greek ideas and expanded on them during the Middle Ages. By the early 17th century, geometry had been put on a solid analytic footing by mathematicians such as René Descartes and Pierre de Fermat. Since then, and into modern times, geometry has expanded into non-Euclidean geometry and manifolds, describing spaces that lie beyond the normal range of human experience.

While geometry has evolved signifcantly throughout the years, there are some general concepts that are more or less fundamental to geometry. Tese include the concepts of points, lines, planes, surfaces, angles, and curves, as well as the more advanced notions of manifolds and topology or metric.

Geometry has applications to many felds, including art, architecture, physics, as well as to other branches of mathematics.

Sacred geometry ascribes symbolic and sacred meanings to certain geometric shapes and certain geometric proportions. It is associated with the belief that a god is the geometer of the world. Te geometry used in the design and construction of religious structures such as churches, temples, mosques, religious monuments, altars, and tabernacles has sometimes been considered sacred. Te concept applies also to sacred spaces such as temenoi, sacred groves, village greens and holy wells, and the creation of religious art.

Examples:

One nanometer is about the length that a fngernail grows in one second. 8 8 o f 1 1 1

Tree gold atoms lined up are about one nanometer long. If a toy marble were scaled down to one nanometer wide, Earth would scale to about one meter (3.3 feet) wide. One nanosecond is about the time required for light to travel 30 cm in air, or 20 cm in an optical fber. Te prefx derives from the Greek νᾶνος (Latin nanus), meaning "dwarf". Te General Conference on Weights and Measures (CGPM) oﬃcially endorsed the usage of nano as a standard prefx in 1960.

Euclidean geometry is a mathematical system attributed to the Alexandrian Greek mathematician Euclid, which he described in his textbook on geometry: the Elements. Euclid's method consists in assuming a small set of intuitively appealing axioms, and deducing many other propositions (theorems) from these. Although many of Euclid's results had been stated by earlier mathematicians,[1] Euclid was the frst to show how these propositions could ft into a comprehensive deductive and logical system.[2] Te Elements begins with plane geometry, still taught in secondary school as the frst axiomatic system and the frst examples of formal proof. It goes on to the solid geometry of three dimensions. Much of the Elements states results of what are now called algebra and number theory, explained in geometrical language.

For more than two thousand years, the adjective "Euclidean" was unnecessary because no other sort of geometry had been conceived. Euclid's axioms seemed so intuitively obvious (with the possible exception of the parallel postulate) that any theorem proved from them was deemed true in an absolute, often metaphysical, sense. Today, however, many other self- consistent non- Euclidean geometries are known, the frst ones having been discovered in the early 19th century. An implication of Albert Einstein's theory of general relativity is that physical space itself is not Euclidean, and Euclidean space is a good approximation for it only where the gravitational feld is weak.

Euclidean geometry is an example of synthetic geometry, in that it proceeds logically from axioms to propositions without the use of coordinates. Tis is in contrast to analytic geometry, which uses coordinates.

231 Chaos theory is a branch of mathematics and it is focused on the behaviour of dynamical systems that are highly sensitive to initial conditions. 'Chaos' is an interdisciplinary theory stating that within the apparent randomness of chaotic complex systems, there are underlying patterns, constant feedback loops, repetition, self-similarity, fractals, self-organization, and reliance on programming at the initial point known as sensitive dependence on initial conditions. Te butterfy eﬀect describes how a small change in one state of a deterministic nonlinear system can result in large diﬀerences in a later state, e.g. a butterfy fapping its wings in Brazil can cause a hurricane in Texas.

Small diﬀerences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for such dynamical systems—a response popularly referred to as the butterfy eﬀect—rendering long- term prediction of their behavior impossible in general. Tis happens even though these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved.[4] In other words, the deterministic nature of these systems does not make them predictable.Tis behavior is known as deterministic chaos, or simply chaos. Te theory was summarized by Edward Lorenz as:

Chaos: When the present determines the future, but the approximate present does not approximately determine the future.

Chaotic behavior exists in many natural systems, such as weather and climate. It also occurs spontaneously in some systems with artifcial components, such as road traﬃc. Tis behavior can be studied through analysis of a chaotic mathematical model, or through analytical techniques such as recurrence plots and Poincaré maps. Chaos theory has applications in several disciplines, including meteorology, anthropology, sociology, physics, environmental science, computer science,

8 9 o f 1 1 1 engineering, economics, biology, ecology, and philosophy. Te theory formed the basis for such felds of study as complex dynamical systems, edge of chaos theory, and self-assembly processes.

In mathematics a fractal is an abstract object used to describe and simulate naturally occurring objects. Artifcially created fractals commonly exhibit similar patterns at increasingly small scales. It is also known as expanding symmetry or evolving symmetry. If the replication is exactly the same at every scale, it is called a self-similar pattern. An example of this is the Menger sponge. Fractals can also be nearly the same at diﬀerent levels. Tis latter pattern is illustrated in small magnifcations of the Mandelbrot set. Fractals also include the idea of a detailed pattern that repeats itself.

Fractals are diﬀerent from other geometric fgures because of the way in which they scale. Doubling the edge lengths of a polygon multiplies its area by four, which is two (the ratio of the new to the old side length) raised to the power of two (the dimension of the space the polygon resides in). Likewise, if the radius of a sphere is doubled, its volume scales by eight, which is two (the ratio of the new to the old radius) to the power of three (the dimension that the sphere resides in). But if a fractal's one-dimensional lengths are all doubled, the spatial content of the fractal scales by a power that is not necessarily an integer. Tis power is called the fractal dimension of the fractal, and it usually exceeds the fractal's topological dimension.

As mathematical equations, fractals are usually nowhere diﬀerentiable. An infnite fractal curve can be conceived of as winding through space diﬀerently from an ordinary line, still being a 1- dimensional line yet having a fractal dimension indicating it also resembles a surface.

Sierpinski carpet (to level 6), a fractal with a topological dimension of 2 and a Hausdorﬀ dimension of 1.893. Te mathematical roots of the idea of fractals have been traced throughout the years as a formal path of published works, starting in the 17th century with notions of recursion, then moving through increasingly rigorous mathematical treatment of the concept to the study of continuous but not diﬀerentiable functions in the 19th century by the seminal work of Bernard Bolzano, Bernhard Riemann, and Karl Weierstrass, and on to the coining of the word fractal in the 20th century with a subsequent burgeoning of interest in fractals and computer-based modelling in the 20th century.Te term "fractal" was frst used by mathematician Benoit Mandelbrot in 1975. Mandelbrot based it on the Latin frāctus meaning "broken" or "fractured", and used it to extend the concept of theoretical fractional dimensions to geometric patterns in nature.:

Tere is some disagreement amongst authorities about how the concept of a fractal should be formally defned. Mandelbrot himself summarized it as "beautiful, damn hard, increasingly useful. Tat's fractals." More formally, in 1982 Mandelbrot stated that "A fractal is by defnition a set for which the Hausdorﬀ-Besicovitch dimension strictly exceeds the topological dimension." Later, seeing this as too restrictive, he simplifed and expanded the defnition to: "A fractal is a shape made of parts similar to the whole in some way." Still later, Mandelbrot settled on this use of the language: "...to use fractal without a pedantic defnition, to use fractal dimension as a generic term applicable to all the variants."

232 Te general consensus is that theoretical fractals are infnitely self-similar, iterated, and detailed mathematical constructs having fractal dimensions, of which many examples have been formulated and studied in great depth. Fractals are not limited to geometric patterns, but can also describe processes in time. Fractal patterns with various degrees of self-similarity have been rendered or studied in images, structures and sounds and found in nature, technology, art, architecture and law. Fractals are of particular relevance in the feld of chaos theory, since the graphs of most chaotic processes are fractal.

Symmetry (from Greek συμμετρία symmetria "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise defnition, that an object is invariant to 9 0 o f 1 1 1 any of various transformations; including refection, rotation or scaling. Although these two meanings of "symmetry" can sometimes be told apart, they are related, so they are here discussed together.

Mathematical symmetry may be observed with respect to the passage of time; as a spatial relationship; through geometric transformations; through other kinds of functional transformations; and as an aspect of abstract objects, theoretic models, language, music and even knowledge itself.

Tis article describes symmetry from three perspectives: in mathematics, including geometry, the most familiar type of symmetry for many people; in science and nature; and in the arts, covering architecture, art and music.

Te opposite of symmetry is asymmetry.

Asymmetry is the absence of, or a violation of, symmetry (the property of an object being invariant to a transformation, such as refection). Symmetry is an important property of both physical and abstract systems and it may be displayed in precise terms or in more aesthetic terms. Te absence of or violation of symmetry that are either expected or desired can have important consequences for a system.

A number is a mathematical object used to count, measure, and label. Te original examples are the natural numbers 1, 2, 3, 4 and so forth. A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, number may refer to a symbol, a word, or a mathematical abstraction.

In mathematics, the notion of number has been extended over the centuries to include 0,negative numbers, rational numbers such as 1/2and −2/3, real numbers such as √2 and π, and complex numbers,[6] which extend the real numbers by adding a square root of −1. Calculations with numbers are done with arithmetical operations, the most familiar being addition, subtraction, multiplication, division, and exponentiation. Teir study or usage is called arithmetic. Te same term may also refer to number theory, the study of the properties of numbers.

Besides their practical uses, numbers have cultural signifcance throughout the world. For example, in Western society, the number 13 is regarded as unlucky, and "a million" may signify "a lot." Tough it is now regarded as pseudoscience, numerology, the belief in a mystical signifcance of numbers, permeated ancient and medieval thought. Numerology heavily infuenced the development of Greek mathematics, stimulating the investigation of many problems in number theory which are still of interest today.

Calculus Calculus (from Latin calculus, literally 'small pebble', used for counting and calculations, like on an abacus) is the mathematical study of continuous change, in the same way that geometry is the study of shape and algebra is the study of generalizations of arithmetic operations. It has two major branches, diﬀerential calculus (concerning rates of change and slopes of curves), and integral 9 1 o f 1 1 1 calculus (concerning accumulation of quantities and the areas under and between curves). Tese two branches are related to each other by the fundamental theorem of calculus. Both branches make use of the fundamental notions of convergence of 233 infnite sequences and infnite series to a well-defned limit. Generally, modern calculus is considered to have been developed in the 17th century by Isaac Newton and Gottfried Wilhelm Leibniz. Today, calculus has widespread uses in science, engineering, and economics.

Calculus is a part of modern mathematics education. A course in calculus is a gateway to other, more advanced courses in mathematics devoted to the study of functions and limits, broadly called mathematical analysis. Calculus has historically been called "the calculus of infnitesimals", or "infnitesimal calculus". Te term calculus (plural calculi) is also used for naming specifc methods of calculation or notation as well as some theories, such as propositional calculus, Ricci calculus, calculus of variations, lambda calculus, and process calculus.

Counting is the action of fnding the number of elements of a fnite set of objects. Te traditional way of counting consists of continually increasing a (mental or spoken) counter by a unit for every element of the set, in some order, while marking (or displacing) those elements to avoid visiting the same element more than once, until no unmarked elements are left; if the counter was set to one after the frst object, the value after visiting the fnal object gives the desired number of elements. Te related term enumeration refers to uniquely identifying the elements of a fnite (combinatorial) set or infnite set by assigning a number to each element.

Counting using tally marks at Hanakapiai Beach Counting sometimes involves numbers other than one; for example, when counting money, counting out change, "counting by twos" (2, 4, 6, 8, 10, 12, ...), or "counting by fves" (5, 10, 15, 20, 25, ...).

Tere is archaeological evidence suggesting that humans have been counting for at least 50,000 years.[1] Counting was primarily used by ancient cultures to keep track of social and economic data such as number of group members, prey animals, property, or debts (i.e., accountancy). Te development of counting led to the development of mathematical notation, numeral systems, and writing.

Measurement is the assignment of a number to a characteristic of an object or event, which can be compared with other objects or events. Te scope and application of a measurement is dependent on the context and discipline. In the natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other felds such as statistics as well as the social and behavioral sciences, measurements can have multiple levels, which would include nominal, ordinal, interval, and ratio scales.

In mathematics, the natural numbers are those used for counting (as in "there are six coins on the table") and ordering (as in "this is the third largest city in the country"). In common language, words used for counting are "cardinal numbers" and words used for ordering are "ordinal numbers".

Some defnitions, including the standard ISO 80000-2, begin the natural numbers with 0, corresponding to the nonnegative integers 0, 1, 2, 3, ..., whereas others start with 1, corresponding to the positive integers 1, 2, 3, .... Texts that exclude zero from the natural numbers

9 2 o f 1 1 1 sometimes refer to the natural numbers together with zero as the whole numbers, but in other writings, that term is used instead for the integers (including negative integers).

Te natural numbers are the basis from which many other number sets may be built by extension: the integers, by including (if not yet in) the neutral element 0 and an additive inverse (−n) for each nonzero natural number n; the rational numbers, by including a multiplicative inverse (1/n) for each nonzero integer n (and also the product of these inverses by integers); the real numbers by including with the rationals the limits of (converging) Cauchy sequences of rationals; the complex numbers, by including with the real numbers the unresolved square root of minus one (and also the sums and products thereof); and so on. Tese chains of extensions make the natural numbers canonically embedded (identifed) in the other number systems.

Properties of the natural numbers, such as divisibility and the distribution of prime numbers, are studied in number theory. Problems concerning counting and ordering, such as partitioning and enumerations, are studied in combinatorics.

In common language, for example in primary school, natural numbers may be called counting numbers[9] both to intuitively exclude the negative integers and zero, and also to contrast the discreteness of counting to the continuity of measurement, established by the real numbers.

234 Te natural numbers can, at times, appear as a convenient set of names (labels), that is, as what linguists call nominal numbers, foregoing many or all of the properties of being a number in a mathematical sense.

In mathematics, a linear order, total order, simple order, or (non-strict) ordering is a binary relation on some set X, which is antisymmetric, transitive, and total (this relation is denoted here by infx. A set paired with a total order is called a totally ordered set, a linearly ordered set, a simply ordered set, or a chain.

More symbolically, a set X is totally ordered under if the following statements hold for all a,b and c in X:

Antisymmetry eliminates uncertain cases when both a precedes b and b precedes a. A relation having the property of "totality" means that any pair of elements in the set of the relation are comparable under the relation. Tis also means that the set can be diagrammed as a line of elements, giving it the name linear.Totality also implies refexivity, i.e., a ≤ a. Terefore, a total order is also a (special case of a) partial order, as, for a partial order, the totality condition is replaced by the weaker condition of refexivity. An extension of a given partial order to a total order is called a linear extension of that partial order.

Algebra (from Arabic "al-jabr" literally meaning "reunion of broken parts") is one of the broad parts of mathematics, together with number theory, geometry and analysis. In its most general form, algebra is the study of mathematical symbols and the rules for manipulating these symbols; it is a unifying thread of almost all of mathematics. As such, it includes everything from elementary equation solving to the study of abstractions such as groups, rings, and felds. Te more basic parts of algebra are called elementary algebra; the more abstract parts are called abstract algebra or modern algebra. Elementary algebra is generally considered to be essential for any study of

9 3 o f 1 1 1 mathematics, science, or engineering, as well as such applications as medicine and economics. Abstract algebra is a major area in advanced mathematics, studied primarily by professional mathematicians.

Ring theory

For a nonassociative ring or algebra {\displaystyle R} R, the associator is the multilinear map {\displaystyle [\cdot ,\cdot , \cdot ]:R\times R\times R\to R} [\cdot,\cdot,\cdot] : R \times R \times R \to R given by

Just as the commutator measures the degree of noncommutativity, the associator measures the degree of nonassociativity of {\displaystyle R} R. For an associative ring or algebra the associator is identically zero.

Te associator in any ring obeys the identity

Te associator is alternating precisely when R is an alternative ring.

Te associator is symmetric in its two rightmost arguments when R is a pre-Lie algebra.

Te nucleus is the set of elements that associate with all others: that is, the n in R such that

Te nucleus is an associative subring of R.

A quasigroup Q is a set with a binary operation.

In higher-dimensional algebra, where there may be non-identity morphisms between algebraic expressions, an associator is an isomorphism

In mathematics, and especially in order theory, a nucleus is a function.

Every nucleus is evidently a monotone function.

235 Frames and locales

Usually, the term nucleus is used in frames and locales theory (when the semilattice {\displaystyle {\mathfrak {A}}} {\mathfrak {A}} is a frame).

Proposition: If {\displaystyle F} F is a nucleus on a frame graphic{\mathfrak (A), then the poset stop./point step {Fix} (F)} \ (operator name){Fix}(F) of fxed points of F, with order inherited from {A}, is also a frame.

In category theory, the associator expresses the associative properties of the internal product functor in monoidal categories.

Monotone refers to a sound, for example music or speech, that has a single unvaried tone. See: monophony.

Sound hides in the light, they travel in a wave.

Monotone refers to a sound, for example music or speech, that has a single unvaried tone. See: monophony. According to Ardis Butternuts (1997), monophony "is the dominant mode of the European vernacular genres as well as of Latin song ... in polyphonic works, it remains a central compositional principle."

Elementary algebra diﬀers from arithmetic in the use of abstractions, such as using letters to stand for numbers that are either unknown or allowed to take on many values.[4] For example, in x+2=5 the letter x is unknown, but the law of inverses can be used to discover its value:. In E = mc2, the letters E and m are variables, and the letter c is a constant, the speed of light in a vacuum. Algebra gives methods for solving equations and expressing formulas that are much easier (for those who know how to use them) than the older method of writing everything out in words.

Te word algebra is also used in certain specialized ways. A special kind of mathematical object in abstract algebra is called an "algebra", and the word is used, for example, in the phrases linear algebra and algebraic topology.

A mathematician who does research in algebra is called an algebraist.

Number theory, or in older usage arithmetic, is a branch of pure mathematics devoted primarily to the study of the integers. It is sometimes called "Te Queen of Mathematics" because of its foundational place in the discipline. Number theorists study prime numbers as well as the properties of objects made out of integers (e.g., rational numbers) or defned as generalizations of the integers (e.g., algebraic integers).

Integers can be considered either in themselves or as solutions to equations (Diophantine geometry). Questions in number theory are often best understood through the study of analytical objects (e.g., the Riemann zeta function) that encode properties of the integers, primes or other number-theoretic objects in some fashion (analytic number theory). One may also study real numbers in relation to rational numbers, e.g., as approximated by the latter (Diophantine approximation).

Te older term for number theory is arithmetic. By the early twentieth century, it had been superseded by "number theory". (Te word "arithmetic" is used by the general public to mean "elementary calculations"; it has also acquired other meanings in mathematical logic, as in Peano arithmetic, and computer science, as in foating point arithmetic.) Te use of the term arithmetic for number theory regained some ground in the second half of the 20th century, arguably in part due to French infuence. In particular, arithmetical is preferred as an adjective to number-theoretic.

Broadly speaking, pure mathematics is mathematics that studies entirely abstract concepts. Tis was a recognizable category of mathematical activity from the 19th century onwards,[1] at variance with the trend towards meeting the needs of navigation, astronomy, physics, economics, engineering, and so on.

Another view is that pure mathematics is not necessarily applied mathematics: it is possible to study abstract entities with respect to their intrinsic nature and not be concerned with how they manifest in the real world.[2] Even though the pure and applied viewpoints are distinct philosophical positions, in practice there is much overlap in the activity of pure and applied mathematicians.

To develop accurate models for describing the real world, many applied mathematicians draw on tools and techniques that are often considered to be "pure" mathematics. On the other hand, many pure mathematicians draw on natural and social phenomena as inspiration for their abstract research.

236 An integer (from the Latin integer meaning "whole") is a number that can be written without a fractional component. For example, 21, 4, 0, and −2048 are integers, while 9.75, 5 1⁄2, and √2 are not. 9 4 o f 1 1 1

Te set of integers consists of zero (0), the positive natural numbers (1, 2, 3, ...), also called whole numbers or counting numbers, and their additive inverses (the negative integers, i.e., −1, −2, −3, ...). Tis is often denoted by a boldface Z ("Z") or blackboard bold standing for the German word Zahlen ([ˈtsaːlən], "numbers").

Z is a subset of the set of all rational numbers Q, in turn a subset of the real numbers R. Like the natural numbers, Z is countably infnite.

Te integers form the smallest group and the smallest ring containing the natural numbers. In algebraic number theory, the integers are sometimes called rational integers to distinguish them from the more general algebraic integers. In fact, the (rational) integers are the algebraic integers that are also rational numbers.

Statistics is a branch of mathematics dealing with the collection, analysis, interpretation, presentation, and organization of data. In applying statistics to, e.g., a scientifc, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model process to be studied. Populations can be diverse topics such as "all people living in a country" or "every atom composing a crystal". Statistics deals with all aspects of data including the planning of data collection in terms of the design of surveys and experiments. See glossary of probability and statistics.

When census data cannot be collected, statisticians collect data by developing specifc experiment designs and survey samples. Representative sampling assures that inferences and conclusions can reasonably extend from the sample to the population as a whole. An experimental study involves taking measurements of the system under study, manipulating the system, and then taking additional measurements using the same procedure to determine if the manipulation has modifed the values of the measurements. In contrast, an observational study does not involve experimental manipulation.

Two main statistical methods are used in data analysis: descriptive statistics, which summarize data from a sample using indexes such as the mean or standard deviation, and inferential statistics, which draw conclusions from data that are subject to random variation (e.g., observational errors, sampling variation). Descriptive statistics are most often concerned with two sets of properties of a distribution (sample or population): central tendency (or location) seeks to characterize the distribution's central or typical value, while dispersion (or variability) characterizes the extent to which members of the distribution depart from its center and each other. Inferences on mathematical statistics are made under the framework of probability theory, which deals with the analysis of random phenomena.

A standard statistical procedure involves the test of the relationship between two statistical data sets, or a data set and synthetic data drawn from idealized model. A hypothesis is proposed for the statistical relationship between the two data sets, and this is compared as an alternative to an idealized null hypothesis of no relationship between two data sets. Rejecting or disproving the null hypothesis is done using statistical tests that quantify the sense in which the null can be proven false, given the data that are used in the test. Working from a null hypothesis, two basic forms of error are recognized: Type I errors (null hypothesis is falsely rejected giving a "false positive") and Type II errors (null hypothesis fails to be rejected and an actual diﬀerence between populations is missed giving a "false negative"). Multiple problems have come to be associated with this framework: ranging from obtaining a suﬃcient sample size to specifying an adequate null hypothesis.[citation needed]

9 5 o f 1 1 1

Measurement processes that generate statistical data are also subject to error. Many of these errors are classifed as random (noise) or systematic (bias), but other types of errors (e.g., blunder, such as when an analyst reports incorrect units) can also be important. Te presence of missing data or censoring may result in biased estimates and specifc techniques have been developed to address these problems.

Statistics can be said to have begun in ancient civilization, going back at least to the 5th century BC, but it was not until the 18th century that it started to draw more heavily from calculus and probability theory.

In mathematics, mean has several diﬀerent defnitions depending on the context.

Probability is the measure of the likelihood that an event will occur. See glossary of probability and statistics. Probability is quantifed as a number between 0 and 1, where, loosely speaking, 0 indicates impossibility and 1 indicates certainty.[3][4] Te higher the probability of an event, the more likely it is that the event will occur. A simple example is the tossing of a fair 237 (unbiased) coin. Since the coin is fair, the two outcomes ("heads" and "tails") are both equally probable; the probability of "heads" equals the probability of "tails"; and since no other outcomes are possible, the probability of either "heads" or "tails" is 1/2 (which could also be written as 0.5 or 50%).

Tese concepts have been given an axiomatic mathematical formalization in probability theory, which is used widely in such areas of study as mathematics, statistics, fnance, gambling, science (in particular physics), artifcial intelligence/machine learning, computer science, game theory, and philosophy to, for example, draw inferences about the expected frequency of events. Probability theory is also used to describe the underlying mechanics and regularities of complex systems.

In probability and statistics, population mean and expected value are used synonymously to refer to one measure of the central tendency either of a probability distribution or of the random variable characterized by that distribution. In the case of a discrete probability distribution of a random variable X, the mean is equal to the sum over every possible value weighted by the probability of that value; that is, it is computed by taking the product of each possible value x of X and its probability P(x), and then adding all these products together, giving \mu =\sum xP(x). An analogous formula applies to the case of a continuous probability distribution. Not every probability distribution has a defned mean; see the Cauchy distribution for an example.

For a data set, the terms arithmetic mean, mathematical expectation, and sometimes average are used synonymously to refer to a central value of a discrete set of numbers: specifcally, the sum of the values divided by the number of values. Te arithmetic mean of a set of numbers x1, x2, ..., xn is typically denoted by, pronounced "x bar". If the data set were based on a series of observations obtained by sampling from a statistical population, the arithmetic mean is termed the sample mean to distinguish it from the population mean.

For a fnite population, the population mean of a property is equal to the arithmetic mean of the given property while considering every member of the population. For example, the population mean height is equal to the sum of the heights of every individual divided by the total number of individuals. Te sample mean may diﬀer from the population mean, especially for small samples. Te law of large numbers dictates that the larger the size of the sample, the more likely it is that the sample mean will be close to the population mean.

Outside probability and statistics, a wide range of other notions of "mean" are often used in geometry and analysis; examples are given below.

Te arithmetic mean (or simply "mean") of a sample is the sum of the sampled values divided by the number of items in the sample:

9 6 o f 1 1 1

Te geometric mean is an average that is useful for sets of positive numbers that are interpreted according to their product and not their sum (as is the case with the arithmetic mean) e.g. rates of growth.

Te harmonic mean is an average which is useful for sets of numbers which are defned in relation to some unit, for example speed (distance per unit of time).

Probability is the measure of the likelihood that an event will occur. See glossary of probability and statistics. Probability is quantifed as a number between 0 and 1, where, loosely speaking, 0 indicates impossibility and 1 indicates certainty. Te higher the probability of an event, the more likely it is that the event will occur. A simple example is the tossing of a fair (unbiased) coin. Since the coin is fair, the two outcomes ("heads" and "tails") are both equally probable; the probability of "heads" equals the probability of "tails"; and since no other outcomes are possible, the probability of either "heads" or "tails" is 1/2 (which could also be written as 0.5 or 50%).

In mathematical analysis, a measure on a set is a systematic way to assign a number to each suitable subset of that set, intuitively interpreted as its size. In this sense, a measure is a generalization of the concepts of length, area, and volume. A particularly important example is the Lebesgue measure on a Euclidean space, which assigns the conventional length, area, and volume of Euclidean geometry to suitable subsets of the n-dimensional Euclidean space Rn. For instance, the Lebesgue measure of the interval [0, 1] in the real numbers is its length in the everyday sense of the word – specifcally, 1.

238 Technically, a measure is a function that assigns a non-negative real number or +∞ to (certain) subsets of a set X (see Defnition below). It must further be countably additive: the measure of a 'large' subset that can be decomposed into a fnite (or countably infnite) number of 'smaller' disjoint subsets, is the sum of the measures of the "smaller" subsets. In general, if one wants to associate a consistent size to each subset of a given set while satisfying the other axioms of a measure, one only fnds trivial examples like the counting measure. Tis problem was resolved by defning measure only on a sub-collection of all subsets; the so-called measurable subsets, which are required to form a σ-algebra. Tis means that countable unions, countable intersections and complements of measurable subsets are measurable. Non-measurable sets in a Euclidean space, on which the Lebesgue measure cannot be defned consistently, are necessarily complicated in the sense of being badly mixed up with their complement. Indeed, their existence is a non-trivial consequence of the axiom of choice.

Measure theory was developed in successive stages during the late 19th and early 20th centuries by Émile Borel, Henri Lebesgue, Johann Radon, and Maurice Fréchet, among others. Te main applications of measures are in the foundations of the Lebesgue integral, in Andrey Kolmogorov's axiomatisation of probability theory and in ergodic theory. In integration theory, specifying a measure allows one to defne integrals on spaces more general than subsets of Euclidean space; moreover, the integral with respect to the Lebesgue measure on Euclidean spaces is more general and has a richer theory than its predecessor, the Riemann integral. Probability theory considers measures that assign to the whole set the size 1, and considers measurable subsets to be events whose probability is given by the measure. Ergodic theory considers measures that are invariant under, or arise naturally from, a dynamical system.

In mathematics, a set is a collection of distinct objects, considered as an object in its own right. For example, the numbers 2, 4, and 6 are distinct objects when considered separately, but when they are considered collectively they form a single set of size three, written {2,4,6}. Te concept of a set 9 7 o f 1 1 1 is one of the most fundamental in mathematics. Developed at the end of the 19th century, set theory is now a ubiquitous part of mathematics, and can be used as a foundation from which nearly all of mathematics can be derived. In mathematics education, elementary topics such as Venn diagrams are taught at a young age, while more advanced concepts are taught as part of a university degree.

Te German word Menge, rendered as "set" in English, was coined by Bernard Bolzano in his work Te Paradoxes of the Infnite.

In mathematics, especially in set theory, a set A is a subset of a set B, or equivalently B is a superset of A, if A is "contained" inside B, that is, all elements of A are also elements of B. A and B may coincide. Te relationship of one set being a subset of another is called inclusion or sometimes containment.

Te subset relation defnes a partial order on sets. Te algebra of subsets forms a Boolean algebra in which the subset relation is called inclusion.

Calculus (from Latin calculus, literally 'small pebble', used for counting and calculations, like on an abacus) is the mathematical study of continuous change, in the same way that geometry is the study of shape and algebra is the study of generalizations of arithmetic operations. It has two major branches, diﬀerential calculus (concerning rates of change and slopes of curves), and integral calculus (concerning accumulation of quantities and the areas under and between curves). Tese two branches are related to each other by the fundamental theorem of calculus. Both branches make use of the fundamental notions of convergence of infnite sequences and infnite series to a well-defned limit. Generally, modern calculus is considered to have been developed in the 17th century by Isaac Newton and Gottfried Wilhelm Leibniz. Today, calculus has widespread uses in science, engineering, and economics.

In mathematics, a function is a relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output. An example is the function that relates each real number x to its square x2. Te output of a function f corresponding to an input x is denoted by f(x) (read "f of x"). In this example, if the input is −3, then the output is 9, and we may write f(−3) = 9. Likewise, if the input is 3, then the output is also 9, and we may write f(3) = 9. (Te same output may be produced by more than one input, but each input gives only one output.) Te input variable(s) are sometimes referred to as the argument(s) of the function.

239 Functions of various kinds are "the central objects of investigation" in most felds of modern mathematics. Tere are many ways to describe or represent a function. Some functions may be defned by a formula or algorithm that tells how to compute the output for a given input. Others are given by a picture, called the graph of the function. In science, functions are sometimes defned by a table that gives the outputs for selected inputs. A function could be described implicitly, for example as the inverse to another function or as a solution of a diﬀerential equation.

In modern mathematics, a function is defned by its set of inputs, called the domain; a set containing the set of outputs, and possibly additional elements, as members, called its codomain (or target); and the set of all input-output pairs, called its graph. Sometimes the codomain is called the function's "range", but more commonly the word "range" is used to mean, instead, specifcally the set of outputs (this is also called the image of the function). For example, we could defne a 9 8 o f 1 1 1 function using the rule f(x) = x2 by saying that the domain and codomain are the real numbers, and that the graph consists of all pairs of real numbers (x, x2). Te image of this function is the set of non-negative real numbers. Collections of functions with the same domain and the same codomain are called function spaces, the properties of which are studied in such mathematical disciplines as real analysis, complex analysis, and functional analysis.

In analogy with arithmetic, it is possible to defne addition, subtraction, multiplication, and division of functions, in those cases where the output is a number. Another important operation defned on functions is function composition, where the output from one function becomes the input to another function.

In mathematics, a formula is an entity constructed using the symbols and formation rules of a given logical language. For example, determining the volume of a sphere requires a signifcant amount of integral calculus or its geometrical analogue, the method of exhaustion; but, having done this once in terms of some parameter (the radius for example), mathematicians have produced a formula to describe the volume:

In mathematics, an integral assigns numbers to functions in a way that can describe displacement, area, volume, and other concepts that arise by combining infnitesimal data. Integration is one of the two main operations of calculus, with its inverse, diﬀerentiation, being the other. Volume is the quantity of three-dimensional space enclosed by a closed surface, for example, the space that a substance (solid, liquid, gas, or plasma) or shape occupies or contains. Volume is often quantifed numerically using the SI derived unit, the cubic metre. Te volume of a container is generally understood to be the capacity of the container; i. e., the amount of fuid (gas or liquid) that the container could hold, rather than the amount of space the container itself displaces. Tree dimensional mathematical shapes are also assigned volumes. Volumes of some simple shapes, such as regular, straight-edged, and circular shapes can be easily calculated using arithmetic formulas. Volumes of a complicated shape can be calculated by integral calculus if a formula exists for the shape's boundary. Where a variance in shape and volume occurs, such as those that exist between diﬀerent human beings, these can be calculated using three-dimensional techniques such as the Body Volume Index. One-dimensional fgures (such as lines) and two-dimensional shapes (such as squares) are assigned zero volume in the three-dimensional space.

A mathematical object is an abstract object arising in mathematics. Te concept is studied in philosophy of mathematics.

In mathematical practice, an object is anything that has been (or could be) formally defned, and with which one may do deductive reasoning and mathematical proofs. Commonly encountered mathematical objects include numbers, permutations, partitions, matrices, sets, functions, and relations. Geometry as a branch of mathematics has such objects as hexagons, points, lines, triangles, circles, spheres, polyhedra, topological spaces and manifolds. Another branch—algebra — has groups, rings, felds, group-theoretic lattices, and order-theoretic lattices. Categories are simultaneously homes to mathematical objects and mathematical objects in their own right. In proof theory, proofs and theorems are also mathematical objects.

Te ontological status of mathematical objects has been the subject of much investigation and debate by philosophers of mathematics.[

In mathematics, an operation is a calculation from zero or more input values (called operands) to an output value. Te number of operands is the arity of the operation. Te most commonly studied operations are binary operations of arity 2, such as addition and multiplication, and unary operations of arity 1, such as additive inverse and multiplicative inverse. An operation of arity zero, or 0-ary operation is a constant. Te mixed product is an example of an operation of arity 3, or 9 9 o f 1 1 1

240 ternary operation. Generally, the arity is supposed to be fnite, but infnitary operations are sometimes considered. In this context, the usual operations, of fnite arity are also called fnitary operations.

Addition (often signifed by the plus symbol "+") is one of the four basic operations of arithmetic; the others are subtraction, multiplication and division. Te addition of two whole numbers is the total amount of those quantities combined. For example, in the picture on the right, there is a combination of three apples and two apples together, making a total of fve apples. Tis observation is equivalent to the mathematical expression "3 + 2 = 5" i.e., "3 add 2 is equal to 5".

Besides counting fruits, addition can also represent combining other physical objects. Using systematic generalizations, addition can also be defned on more abstract quantities, such as integers, rational numbers, real numbers and complex numbers and other abstract objects such as vectors and matrices.

In arithmetic, rules for addition involving fractions and negative numbers have been devised amongst others. In algebra, addition is studied more abstractly.

Addition has several important properties. It is commutative, meaning that order does not matter, and it is associative, meaning that when one adds more than two numbers, the order in which addition is performed does not matter (see Summation). Repeated addition of 1 is the same as counting; addition of 0 does not change a number. Addition also obeys predictable rules concerning related operations such as subtraction and multiplication.

Performing addition is one of the simplest numerical tasks. Addition of very small numbers is accessible to toddlers; the most basic task, 1 + 1, can be performed by infants as young as fve months and even some members of other animal species. In primary education, students are taught to add numbers in the decimal system, starting with single digits and progressively tackling more diﬃcult problems. Mechanical aids range from the ancient abacus to the modern computer, where research on the most eﬃcient implementations of addition continues to this day.

Subtraction is an arithmetic operation that represents the operation of removing objects from a collection. It is signifed by the minus sign (−). For example, in the picture on the right, there are 5 − 2 apples—meaning 5 apples with 2 taken away, which is a total of 3 apples. Terefore, 5 − 2 = 3. Subtraction represents removing or decreasing physical and abstract quantities using diﬀerent kinds of objects including negative numbers, fractions, irrational numbers, vectors, decimals, functions, and matrices.

Subtraction follows several important patterns. It is anticommutative, meaning that changing the order changes the sign of the answer. It is not associative, meaning that when one subtracts more than two numbers, the order in which subtraction is performed matters. Subtraction of 0 does not change a number. Subtraction also obeys predictable rules concerning related operations such as addition and multiplication. All of these rules can be proven, starting with the subtraction of integers and generalizing up through the real numbers and beyond. General binary operations that continue these patterns are studied in abstract algebra.

Performing subtraction is one of the simplest numerical tasks. Subtraction of very small numbers is accessible to young children. In primary education, students are taught to subtract numbers in the decimal system, starting with single digits and progressively tackling more diﬃcult problems.

In advanced algebra and in computer algebra, an expression involving subtraction like A − B is generally treated as a shorthand notation for the addition A + (−B). Tus, A − B contains two terms, namely A and −B. Tis allows an easier use of associativity and commutativity.

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A complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1, which is called an imaginary number because there is no real number that satisfes this equation. For the complex number a + bi, a is called the

1 0 1 o f 1 1 1 real part, and b is called the imaginary part. Despite the historical nomenclature "imaginary", complex numbers are regarded in the mathematical sciences as just as "real" as the real numbers, and are fundamental in many aspects of the scientifc description of the natural world.

241 Te complex number system can be defned as the algebraic extension of the ordinary real numbers by an imaginary number i. Tis means that complex numbers can be added, subtracted, and multiplied, as polynomials in the variable i, with the rule i2 = −1 imposed. Furthermore, complex numbers can also be divided by nonzero complex numbers. Overall, the complex number system is a feld.

Most importantly the complex numbers give rise to the fundamental theorem of algebra: every non- constant polynomial equation with complex coeﬃcients has a complex solution. Tis property is true of the complex numbers, but not the reals. Te 16th century Italian mathematician Gerolamo Cardano is credited with introducing complex numbers in his attempts to fnd solutions to cubic equations.

Geometrically, complex numbers extend the concept of the one-dimensional number line to the two-dimensional complex plane by using the horizontal axis for the real part and the vertical axis for the imaginary part. Te complex number a + bi can be identifed with the point (a, b) in the complex plane. A complex number whose real part is zero is said to be purely imaginary; the points for these numbers lie on the vertical axis of the complex plane. A complex number whose imaginary part is zero can be viewed as a real number; its point lies on the horizontal axis of the complex plane. Complex numbers can also be represented in polar form, which associates each complex number with its distance from the origin (its magnitude) and with a particular angle known as the argument of this complex number.

In mathematics, physics, and engineering, a Euclidean vector (sometimes called a geometric or spatial vector, or—as here— simply a vector) is a geometric object that has magnitude (or length) and direction. Vectors can be added to other vectors according to vector algebra. A Euclidean vector is frequently represented by a line segment with a defnite direction, or graphically as an arrow, connecting an initial point A with a terminal point B.

A vector is what is needed to "carry" the point A to the point B; the Latin word vector means "carrier". It was frst used by 18th century astronomers investigating planet rotation around the Sun. Te magnitude of the vector is the distance between the two points and the direction refers to the direction of displacement from A to B. Many algebraic operations on real numbers such as addition, subtraction, multiplication, and negation have close analogues for vectors, operations which obey the familiar algebraic laws of commutativity, associativity, and distributivity. Tese operations and associated laws qualify Euclidean vectors as an example of the more generalized concept of vectors defned simply as elements of a vector space.

Vectors play an important role in physics: the velocity and acceleration of a moving object and the forces acting on it can all be described with vectors. Many other physical quantities can be usefully thought of as vectors. Although most of them do not represent distances (except, for example, position or displacement), their magnitude and direction can still be represented by the length and direction of an arrow. Te mathematical representation of a physical vector depends on the coordinate system used to describe it. Other vector-like objects that describe physical quantities and transform in a similar way under changes of the coordinate system include pseudovectors and tensors.

In mathematics, magnitude is the size of a mathematical object, a property which determines whether the object is larger or smaller than other objects of the same kind. More formally, an object's magnitude is the displayed result of an ordering (or ranking) of the class of objects to which it belongs.

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Te most common relative directions are left, right, forward(s), backward(s), up, and down. No absolute direction corresponds to any of the relative directions. Tis is a consequence of the translational invariance of the laws of physics: nature, loosely speaking, behaves the same no matter what direction one moves. As demonstrated by the Michelson-Morley null result, there is no absolute inertial frame of reference. Tere are defnite relationships between the relative directions, however. Left and right, forward and backward, and up and down are three pairs of complementary directions, each pair orthogonal to both of the others. Relative directions are also known as egocentric coordinates.

In mathematics, a square root of a number a is a number y such that y2 = a; in other words, a number y whose square (the result of multiplying the number by itself, or y⋅y) is a.[1] For example, 4 and −4 are square roots of 16 because 42 = (−4)2 = 16. Every nonnegative real number a has a unique nonnegative square root, called the principal square root, which is denoted by √a, where √ is called the radical sign or radix. For example, the principal square root of 9 is 3, which is denoted by √9 = 3, because 32 = 3 • 3 = 9 and 3 is nonnegative. Te term (or number) whose square root is being considered is known as the radicand. Te radicand is the number or expression underneath the radical sign, in this example 9.

Every positive number a has two square roots: √a, which is positive, and −√a, which is negative. Together, these two roots are denoted as ± √a (see ± shorthand). Although the principal square root of a positive number is only one of its two square

242 roots, the designation "the square root" is often used to refer to the principal square root. For positive a, the principal square root can also be written in exponent notation, as a1/2.

Square roots of negative numbers can be discussed within the framework of complex numbers. More generally, square roots can be considered in any context in which a notion of "squaring" of some mathematical objects is defned (including algebras of matrices, endomorphism rings, etc

Maths and existence:

First-order logic—also known as frst-order predicate calculus and predicate logic—is a collection of formal systems used in mathematics, philosophy, linguistics, and computer science. First-order logic uses quantifed variables over non-logical objects and allows the use of sentences that contain variables, so that rather than propositions such as Socrates is a man one can have expressions in the form "there exists X such that X is Socrates and X is a man" and there exists is a quantifer while X is a variable.[1] Tis distinguishes it from propositional logic, which does not use quantifers or relations.

A theory about a topic is usually a frst-order logic together with a specifed domain of discourse over which the quantifed variables range, fnitely many functions from that domain to itself, fnitely many predicates defned on that domain, and a set of axioms believed to hold for those things. Sometimes "theory" is understood in a more formal sense, which is just a set of sentences in frst- order logic.

Te adjective "frst-order" distinguishes frst-order logic from higher-order logic in which there are predicates having predicates or functions as arguments, or in which one or both of predicate quantifers or function quantifers are permitted. In frst-order theories, predicates are often associated with sets. In interpreted higher-order theories, predicates may be interpreted as sets of sets.

Tere are many deductive systems for frst-order logic which are both sound (all provable statements are true in all models) and complete (all statements which are true in all models are provable). Although the logical consequence relation is only semidecidable, much progress has been made in automated theorem proving in frst-order logic. First-order logic also satisfes several

1 0 3 o f 1 1 1 metalogical theorems that make it amenable to analysis in proof theory, such as the Löwenheim– Skolem theorem and the compactness theorem.

First-order logic is the standard for the formalization of mathematics into axioms and is studied in the foundations of mathematics. Peano arithmetic and Zermelo–Fraenkel set theory are axiomatizations of number theory and set theory, respectively, into frst-order logic. No frst-order theory, however, has the strength to uniquely describe a structure with an infnite domain, such as the natural numbers or the real line. Axioms systems that do fully describe these two structures (that is, categorical axiom systems) can be obtained in stronger logics such as second-order logic.

Te foundations of frst-order logic were developed independently by Gottlob Frege and Charles Sanders Peirce. For a history of frst-order logic and how it came to dominate formal logic, see José Ferreirós (2001).

In predicate logic, an existential quantifcation is a type of quantifer, a logical constant which is interpreted as "there exists", "there is at least one", or "for some". Some sources use the term existentialization to refer to existential quantifcation. It is usually denoted by the turned E (∃) logical operator symbol, which, when used together with a predicate variable, is called an existential quantifer ("∃x" or "∃(x)"). Existential quantifcation is distinct from universal quantifcation ("for all"), which asserts that the property or relation holds for all members of the domain.

In predicate logic, a universal quantifcation is a type of quantifer, a logical constant which is interpreted as "given any" or "for all". It expresses that a propositional function can be satisfed by every member of a domain of discourse. In other words, it is the predication of a property or relation to every member of the domain. It asserts that a predicate within the scope of a universal quantifer is true of every value of a predicate variable.

It is usually denoted by the turned A (∀) logical operator symbol, which, when used together with a predicate variable, is called a universal quantifer ("∀x", "∀(x)", or sometimes by "(x)" alone).

Universal quantifcation is distinct from existential quantifcation ("there exists"), which only asserts that the property or relation holds for at least one member of the domain. 243 Quantifcation in general is covered in the article on quantifcation (logic). Symbols are encoded U +2200 ∀ FOR ALL (HTML ∀ · ∀ · as a mathematical symbol).

In logic, quantifcation specifes the quantity of specimens in the domain of discourse that satisfy an open formula. Te two most common quantifers mean "for all" and "there exists". For example, in arithmetic, quantifers allow one to say that the natural numbers go on for ever, by writing that for all n (where n is a natural number), there is another number (say, the successor of n) which is one bigger than n.

A language element which generates a quantifcation (such as "every") is called a quantifer. Te resulting expression is a quantifed expression, it is said to be quantifed over the predicate (such as "the natural number x has a successor") whose free variable is bound by the quantifer. In formal languages, quantifcation is a formula constructor that produces new formulas from old ones. Te semantics of the language specifes how the constructor is interpreted. Two fundamental kinds of quantifcation in predicate logic are universal quantifcation and existential quantifcation. Te traditional symbol for the universal quantifer "all" is "∀", a rotated letter "A", and for the existential quantifer "exists" is "∃", a rotated letter "E". Tese quantifers have been generalized beginning with the work of Mostowski and Lidström.

Quantifcation is used as well in natural languages; examples of quantifers in English are for all, for some, many, few, a lot, and no; see Quantifer (linguistics) for details.

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Te term has subtle diﬀerences in defnition when used in the context of diﬀerent felds of study. As defned in classic philosophy, an axiom is a statement that is so evident or well-established, that it is accepted without controversy or question. As used in modern logic, an axiom is simply a premise or starting point for reasoning.

In both senses, an axiom is any mathematical statement that serves as a starting point from which other statements are logically derived. Whether it is meaningful (and, if so, what it means) for an axiom, or any mathematical statement, to be "true" is an open question[citation needed] in the philosophy of mathematics.

In mathematics, a self-similar object is exactly or approximately similar to a part of itself (i.e. the whole has the same shape as one or more of the parts). Many objects in the real world, such as coastlines, are statistically self-similar: parts of them show the same statistical properties at many scales.[2] Self-similarity is a typical property of artifcial fractals. Scale invariance is an exact form of self-similarity where at any magnifcation there is a smaller piece of the object that is similar to the whole. For instance, a side of the Koch snowfake is both symmetrical and scale-invariant; it can be continually magnifed 3x without changing shape. Te non-trivial similarity evident in fractals is distinguished by their fne structure, or detail on arbitrarily small scales. As a counterexample, whereas any portion of a straight line may resemble the whole, further detail is not revealed.

A time developing phenomenon is said to exhibit self-similarity if the numerical value of certain observable traits quantity to be measured at different times are different but the corresponding dimensionless quantity at given value of remain invariant. It happens if the quantity exhibits dynamic scaling. Te idea is just an extension of the idea of similarity of two triangles. Note that two triangles are similar if the numerical values of their sides are different however the corresponding dimensionless quantities, such as their angles, coincide.

In topology and related branches of mathematics, a topological space may be defned as a set of points, along with a set of neighbourhoods for each point, satisfying a set of axioms relating points and neighbourhoods. Te defnition of a topological space relies only upon set theory and is the most general notion of a mathematical space that allows for the defnition of 244 concepts such as continuity, connectedness, and convergence. Other spaces, such as manifolds and metric spaces, are specializations of topological spaces with extra structures or constraints. Being so general, topological spaces are a central unifying notion and appear in virtually every branch of modern mathematics. Te branch of mathematics that studies topological spaces in their own right is called point-set topology or general topology.

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In mathematics, a continuous function is a function for which suﬃciently small changes in the input result in arbitrarily small changes in the output. Otherwise, a function is said to be a discontinuous function. A continuous function with a continuous inverse function is called a homeomorphism.

Continuity of functions is one of the core concepts of topology, which is treated in full generality below. Te introductory portion of this article focuses on the special case where the inputs and outputs of functions are real numbers. A stronger form of continuity is uniform continuity. In addition, this article discusses the defnition for the more general case of functions between two metric spaces. In order theory, especially in domain theory, one considers a notion of continuity known as Scott continuity. Other forms of continuity do exist but they are not discussed in this article.

As an example, consider the function h(t), which describes the height of a growing fower at time t. Tis function is continuous. By contrast, if M(t) denotes the amount of money in a bank account at time t, then the function jumps at each point in time when money is deposited or withdrawn, so the function M(t) is discontinuous.

In topology and related branches of mathematics, a connected space is a topological space that cannot be represented as the union of two or more disjoint nonempty open subsets. Connectedness is one of the principal topological properties that are used to distinguish topological spaces.

A subset of a topological space X is a connected set if it is a connected space when viewed as a subspace of X.

In mathematics, the limit of a sequence is the value that the terms of a sequence "tend to". If such a limit exists, the sequence is called convergent. A sequence which does not converge is said to be divergent. Te limit of a sequence is said to be the fundamental notion on which the whole of analysis ultimately rests.

Limits can be defned in any metric or topological space, but are usually frst encountered in the real numbers.

Te Mandelbrot set is the set of complex numbers for which the function does not diverge when iterated from i.e., for which the sequence etc., remains bounded in absolute value.

A zoom sequence illustrating the set of complex numbers termed the Mandelbrot set. Its defnition and name are due to Adrien Douady, in tribute to the mathematician Benoit Mandelbrot.[1] Te set is connected to a Julia set, and related Julia sets produce similarly complex fractal shapes.

Mandelbrot set images may be created by sampling the complex numbers and testing, for each sample point, whether the sequence goes to infnity (in practice -- whether it leaves some predetermined bounded neighbourhood of 0 after a predetermined number of iterations). Treating the real and imaginary parts of it as image coordinates on the complex plane, pixels may then be coloured according to how soon the sequence crosses an arbitrarily chosen threshold, with a special color (usually black) used for the values of which the sequence has not crossed the threshold after the predetermined number of iterations (this is necessary to clearly distinguish the Mandlebrot set image from the image of its complement). If it is held constant and the initial value of it is variable instead, one obtains the corresponding Julia set for each point c in the parameter space of the simple function.

Images of the Mandelbrot set exhibit an elaborate and infnitely complicated boundary that reveals progressively ever-fner recursive detail at increasing magnifcations. Te "style" of this repeating detail depends on the region of the set being examined. Te set's boundary also incorporates 1 0 6 o f 1 1 1 smaller versions of the main shape, so the fractal property of self-similarity applies to the entire set, and not just to its parts.

Te Mandelbrot set has become popular outside mathematics both for its aesthetic appeal and as an example of a complex structure arising from the application of simple rules. It is one of the best- known examples of mathematical visualization.

245 In mathematics a fractal is an abstract object used to describe and simulate naturally occurring objects. Artifcially created fractals commonly exhibit similar patterns at increasingly small scales. It is also known as expanding symmetry or evolving symmetry. If the replication is exactly the same at every scale, it is called a self-similar pattern. An example of this is the Menger sponge. Fractals can also be nearly the same at diﬀerent levels. Tis latter pattern is illustrated in small magnifcations of the Mandelbrot set. Fractals also include the idea of a detailed pattern that repeats itself.

Sierpinski carpet (to level 6), a fractal with a topological dimension of 2 and a Hausdorﬀ dimension of 1.893 Te mathematical roots of the idea of fractals have been traced throughout the years as a formal path of published works, starting in the 17th century with notions of recursion, then moving through increasingly rigorous mathematical treatment of the concept to the study of continuous but not diﬀerentiable functions in the 19th century by the seminal work of Bernard Bolzano, Bernhard Riemann, and Karl Weierstrass, and on to the coining of the word fractal in the 20th century with a subsequent burgeoning of interest in fractals and computer-based modelling in the 20th century. Te term "fractal" was frst used by mathematician Benoit Mandelbrot in 1975. Mandelbrot based it on the Latin frāctus meaning "broken" or "fractured", and used it to extend the concept of theoretical fractional dimensions to geometric patterns in nature.

Tere is some disagreement amongst authorities about how the concept of a fractal should be formally defned. Mandelbrot himself summarized it as "beautiful, damn hard, increasingly useful. Tat's fractals." More formally, in 1982 Mandelbrot stated that "A fractal is by defnition a set for which the Hausdorﬀ-Besicovitch dimension strictly exceeds the topological dimension.” Later, seeing this as too restrictive, he simplifed and expanded the defnition to: "A fractal is a shape made of parts similar to the whole in some way." Still later, Mandelbrot settled on this use of the language: "...to use fractal without a pedantic defnition, to use fractal dimension as a generic term applicable to all the variants."

Te general consensus is that theoretical fractals are infnitely self-similar, iterated, and detailed mathematical constructs having fractal dimensions, of which many examples have been formulated and studied in great depth. Fractals are not limited to geometric patterns, but can also describe processes in time. Fractal patterns with various degrees of self-similarity have been rendered or studied in images, structures and sounds and found in nature, technology, art, architecture and

1 0 7 o f 1 1 1 law. Fractals are of particular relevance in the feld of chaos theory, since the graphs of most chaotic processes are fractal.

Singularity

In mathematics, a singularity is in general a point at which a given mathematical object is not defned, or a point of an exceptional set where it fails to be well-behaved in some particular way, such as diﬀerentiability.

For example, the real function x has a singularity at x = 0, where it seems to "explode" to ±∞ and is not defned. Te function g(x) = |x| (see absolute value) also has a singularity at x = 0, since it is not diﬀerentiable there.

Te algebraic curve in the (x, y) coordinate system has a singularity (called a cusp) at (0, 0). See Singular point of an algebraic variety for details on singularities in algebraic geometry. See Singularity theory for singularities in diﬀerential geometry.

Mathematical logic is a subfeld of mathematics exploring the applications of formal logic to mathematics. It bears close connections to metamathematics, the foundations of mathematics, and theoretical computer science. Te unifying themes in mathematical logic include the study of the expressive power of formal systems and the deductive power of formal proof systems.

246 Mathematical logic is often divided into the felds of set theory, model theory, recursion theory, and proof theory. Tese areas share basic results on logic, particularly frst-order logic, and defnability. In computer science, mathematical logic encompasses additional topics not detailed in this article; see Logic in computer science for those.

Since its inception, mathematical logic has both contributed to, and has been motivated by, the study of foundations of mathematics. Tis study began in the late 19th century with the development of axiomatic frameworks for geometry, arithmetic, and analysis. In the early 20th century it was shaped by David Hilbert's program to prove the consistency of foundational theories. Results of Kurt Gödel, Gerhard Gentzen, and others provided partial resolution to the program, and clarifed the issues involved in proving consistency. Work in set theory showed that almost all ordinary mathematics can be formalized in terms of sets, although there are some theorems that cannot be proven in common axiom systems for set theory. Contemporary work in the foundations of mathematics often focuses on establishing which parts of mathematics can be formalized in particular formal systems (as in reverse mathematics) rather than trying to fnd theories in which all of mathematics can be developed.

Te strength of an earthquake is measured by taking the common logarithm of the energy emitted at the quake. Tis is used in the moment magnitude scale or the Richter magnitude scale. For example, a 5.0 earthquake releases 32 times (101.5) and a 6.0 releases 1000 times (103) the energy of a 4.0.[61] Another logarithmic scale is apparent magnitude. It measures the brightness of stars logarithmically.[62] Yet another example is pH in chemistry; pH is the negative of the common logarithm of the activity of hydronium ions (the form hydrogen ions H+ take in water).[63] Te activity of hydronium ions in neutral water is 10−7 mol·L−1, hence a pH of 7. Vinegar typically has a pH of about 3. Te diﬀerence of 4 corresponds to a ratio of 104 of the activity, that is, vinegar's hydronium ion activity is about 10−3 mol·L−1.

Semilog (log-linear) graphs use the logarithmic scale concept for visualization: one axis, typically the vertical one, is scaled logarithmically. For example, the chart at the right compresses the steep increase from 1 million to 1 trillion to the same space (on the vertical axis) as the increase from 1 to 1 million. In such graphs, exponential functions of the form f(x) = a · bx appear as straight lines with slope equal to the logarithm of b. Log-log graphs scale both axes logarithmically, which causes

1 0 8 o f 1 1 1 functions of the form f(x) = a · xk to be depicted as straight lines with slope equal to the exponent k. Tis is applied in visualizing and analyzing power laws.[64]

Logarithms occur in several laws describing human perception:[65][66] Hick's law proposes a logarithmic relation between the time individuals take to choose an alternative and the number of choices they have.[67] Fitts's law predicts that the time required to rapidly move to a target area is a logarithmic function of the distance to and the size of the target.[68] In psychophysics, the Weber–Fechner law proposes a logarithmic relationship between stimulus and sensation such as the actual vs. the perceived weight of an item a person is carrying.[69] (Tis "law", however, is less precise than more recent models, such as the Stevens' power law.[70])

Psychological studies found that individuals with little mathematics education tend to estimate quantities logarithmically, that is, they position a number on an unmarked line according to its logarithm, so that 10 is positioned as close to 100 as 100 is to 1000. Increasing education shifts this to a linear estimate (positioning 1000 10x as far away) in some circumstances, while logarithms are used when the numbers to be plotted are diﬃcult to plot linearly.

Plots of logarithm functions of three commonly used bases. Te special points logb b = 1 are indicated by dotted lines, and logb 1 = 0 is where the curves intersect. In mathematics, the logarithm is the inverse function to exponentiation. Tat means the logarithm of a given number x is the exponent to which another fxed number, the base b, must be raised, to produce that number x. In the simplest case the logarithm counts repeated multiplication of the same factor; e.g., since 1000 = 10 × 10 × 10 = 103, the "logarithm to base 10" of 1000 is 3. Te logarithm of x to base b is denoted as logb (x) (or, without parentheses, as logb x, or even without explicit base as log x, when no confusion is possible). More generally, exponentiation allows any positive real number to be raised to any real power, always producing a positive result, so the logarithm for any two positive real numbers b and x where b is not equal to 1, is always a unique real number y. More explicitly, the defning relation between exponentiation and logarithm is:

{\displaystyle \log _{b}(x)=y\quad } {\displaystyle \log _{b}(x)=y\quad } exactly if {\displaystyle \quad b^{y}=x.} {\displaystyle \quad b^{y}=x.} For example, log2 64 = 6, as 64 = 26.

247 Te logarithm to base 10 (that is b = 10) is called the common logarithm and has many applications in science and engineering. Te natural logarithm has the number e (that is b ≈ 2.718) as its base; its use is widespread in mathematics and physics, because of its simpler derivative. Te binary logarithm uses base 2 (that is b = 2) and is commonly used in computer science.

Logarithms were introduced by John Napier in the early 17th century as a means to simplify calculations. Tey were rapidly adopted by navigators, scientists, engineers, and others to perform computations more easily, using slide rules and logarithm tables. Tedious multi-digit multiplication steps can be replaced by table look-ups and simpler addition because of the fact— important in its own right—that the logarithm of a product is the sum of the logarithms of the factors:

{\displaystyle \log _{b}(xy)=\log _{b}x+\log _{b}y,\,} {\displaystyle \log _{b}(xy)=\log _{b}x+\log _{b}y, \,} provided that b, x and y are all positive and b ≠ 1. Te present-day notion of logarithms comes from Leonhard Euler, who connected them to the exponential function in the 18th century.

Logarithmic scales reduce wide-ranging quantities to tiny scopes. For example, the decibel (dB) is a unit used to express log- ratios, mostly for signal power and amplitude (of which sound pressure is a common example). In chemistry, pH is a logarithmic measure for the acidity of an aqueous solution. Logarithms are commonplace in scientifc formulae, and in measurements of the complexity of algorithms and of geometric objects called fractals. Tey help describing frequency

1 0 9 o f 1 1 1 ratios of musical intervals, appear in formulas counting prime numbers or approximating factorials, inform some models in psychophysics, and can aid in forensic accounting.

In the same way as the logarithm reverses exponentiation, the complex logarithm is the inverse function of the exponential function applied to complex numbers. Te discrete logarithm is another variant; it has uses in public-key cryptography.

Entropy and chaos

An oval shape with the trajectories of two particles. Billiards on an oval billiard table. Two particles, starting at the center with an angle diﬀering by one degree, take paths that diverge chaotically because of refections at the boundary. Entropy is broadly a measure of the disorder of some system. In statistical thermodynamics, the entropy S of some physical system is defned as

Te sum is over all possible states i of the system in question, such as the positions of gas particles in a container. Moreover, pi is the probability that the state i is attained and k is the Boltzmann constant. Similarly, entropy in information theory measures the quantity of information. If a message recipient may expect any one of N possible messages with equal likelihood, then the amount of information conveyed by any one such message is quantifed as log2(N) bits.[85]

Lyapunov exponents use logarithms to gauge the degree of chaoticity of a dynamical system. For example, for a particle moving on an oval billiard table, even small changes of the initial conditions result in very diﬀerent paths of the particle. Such systems are chaotic in a deterministic way, because small measurement errors of the initial state predictably lead to largely diﬀerent fnal states.[86] At least one Lyapunov exponent of a deterministically chaotic system is positive.

Fractals Parts of a triangle are removed in an iterated way. Te Sierpinski triangle (at the right) is constructed by repeatedly replacing equilateral triangles by three smaller ones. Logarithms occur in defnitions of the dimension of fractals.[87] Fractals are geometric objects that are self-similar: small parts reproduce, at least roughly, the entire global structure. Te Sierpinski triangle (pictured) can be covered by three copies of itself, each having sides half the original length. Tis makes the Hausdorﬀ dimension of this structure ln(3)/ln(2) ≈ 1.58. Another logarithm- based notion of dimension is obtained by counting the number of boxes needed to cover the fractal in question.

Music Four different octaves shown on a linear scale. Four different octaves shown on a logarithmic scale. Four different octaves shown on a linear scale, then shown on a logarithmic scale (as the ear hears them). Logarithms are related to musical tones and intervals. In equal temperament, the frequency ratio depends only on the interval between two tones, not on the specifc frequency, or pitch, of the individual tones. For example, the note A has a 248 frequency of 440 Hz and B-fat has a frequency of 466 Hz. Te interval between A and B-fat is a semitone, as is the one between B-fat and B (frequency 493 Hz). Accordingly, the frequency ratios agree:

Terefore, logarithms can be used to describe the intervals: an interval is measured in semitones by taking the base-21/12 logarithm of the frequency ratio, while the base-21/1200 logarithm of the frequency ratio expresses the interval in cents, hundredths of a semitone. Te latter is used for fner encoding, as it is needed for non-equal temperaments.[88]

1 1 0 o f 1 1 1

Exponentiation is a mathematical operation, written as bn, involving two numbers, the base b and the exponent n. When n is a positive integer, exponentiation corresponds to repeated multiplication of the base: that is, bn is the product of multiplying n bases:

Te exponent is usually shown as a superscript to the right of the base. In that case, bn is called "b raised to the n-th power", "b raised to the power of n", or "the n-th power of b".

When n is a positive integer and b is not zero, b−n is naturally defned as, preserving the property bn × bm = bn + m. With exponent −1, b−1 is equal to 1/b, and is the reciprocal of b.

Te defnition of exponentiation can be extended to allow any real or complex exponent. Exponentiation by integer exponents can also be defned for a wide variety of algebraic structures, including matrices.

Exponentiation is used extensively in many felds, including economics, biology, chemistry, physics, and computer science, with applications such as compound interest, population growth, chemical reaction kinetics, wave behavior, and public-key cryptography.

7) Technology and Computing

Technology ("science of craft", from Greek τέχνη, techne, "art, skill, cunning of hand"; and -λογία, -logia) is the collection of techniques, skills, methods, and processes used in the production of goods or services or in the accomplishment of objectives, such as scientifc investigation. Technology can be the knowledge of techniques, processes, and the like, or it can be embedded in machines to allow for operation without detailed knowledge of their workings.

Te simplest form of technology is the development and use of basic tools. Te prehistoric discovery of how to control fre and the later Neolithic Revolution increased the available sources of food, and the invention of the wheel helped humans to travel in and control their environment. Developments in historic times, including the printing press, the telephone, and the Internet, have lessened physical barriers to communication and allowed humans to interact freely on a global scale. For example, the Internet (contraction of interconnected network) is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. Te Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and fle 249 sharing. Te Internet has no single centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own policies.[4] Te overreaching defnitions of the two principal name spaces in the Internet, the Internet Protocol address (IP address) and is connected by data trans/rec by data signaller and packets - space - cyber division. You can also produce gas by splitting water, 2 ferrile coil’s connected to at power source of 28v 10w into a tank with the two points and collect the gases of hydrogen then combine them as gases they will burn too produce a water vapour.

Technology has many eﬀects. It has helped develop more advanced economies (including today's global economy) and has allowed the rise of a leisure class. Many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earth's environment. Innovations have always infuenced the values of a society and raised new questions of the ethics of technology. Examples include the rise of the notion of eﬃciency in terms of human productivity, and the challenges of bioethics.

Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the human condition or worsens it. Neo- Luddism, anarcho-primitivism, and similar reactionary movements criticize the pervasiveness of technology, arguing that it harms the environment and alienates people; proponents of ideologies such as transhumanism and techno-progressivism view continued technological progress as benefcial to society and the human condition.

‘Calculable by fnite means’ was Turing's characterisation of computability, Turing’s Philosophy. Te phrase “Te Turing Test” is most properly used to refer to a proposal made by Turing (1950) as a way of dealing with the question whether machines can think. According to Turing, the question whether machines can think is itself “too meaningless” to deserve discussion (442). However, if we consider the more precise—and somehow related—question whether a digital computer can do well in a certain kind of game that Turing describes (“Te Imitation Game”), then—at least in Turing's eyes—we do have a question that admits of precise discussion. Moreover, as we shall see, Turing himself thought that it would not be too long before we did have digital computers that could “do well” in the Imitation Game.

Digital data, in information theory and information systems, is the discrete, discontinuous representation of information or works. Numbers and letters are commonly used representations.

Digital data can be contrasted with analog signals which behave in a continuous manner, and with continuous functions such as sounds, images, and other measurements.

A programming language is a formal language that specifes a set of instructions that can be used to produce various kinds of output. Programming languages generally consist of instructions for a computer. Programming languages can be used to create programs that implement specifc algorithms.

Te description of a programming language is usually split into the two components of syntax (form) and semantics (meaning). Some languages are defned by a specifcation document (for example, the C programming language is specifed by an ISO Standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defned by a standard and extensions taken from the dominant implementation being common.

Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which may contain data, in the form of felds, often known as attributes; and code, in the form of procedures, often known as methods. A feature of objects is that an object's procedures can access and often modify the data felds of the object with which they are associated (objects have a notion of "this" or "self"). In OOP, computer programs are designed by making them out of objects that interact with one another.[1][2] Tere is signifcant diversity of OOP languages, but the most popular ones are class-based, meaning that objects are instances of classes, which typically also determine their type.

In computer science, an object can be a variable, a data structure, a function, or a method, and as such, is a value in memory referenced by an identifer.

In logic, mathematics, and computer science, the arity /ˈærɪti/ (About this soundlisten) of a function or operation is the number of arguments or operands that the function takes. Te arity of a relation (or predicate) is the dimension of the domain in the corresponding Cartesian product. (A function of arity n thus has arity n+1 considered as a relation.) Te term springs from words like unary, binary, ternary, etc. Unary functions or predicates may be also called "monadic"; similarly, binary functions may be called "dyadic". 250 In mathematics, arity may also be named rank, but this word can have many other meanings in mathematics. In logic and philosophy, arity is also called adicity and degree. In linguistics, arity is usually named valency.

In computer programming, there is often a syntactical distinction between operators and functions; syntactical operators usually have arity 0, 1, or 2 (the ternary operator ?: is also common). Functions vary widely in the number of arguments, though large numbers can become unwieldy. Some programming languages also oﬀer support for variadic functions, i.e., functions syntactically accepting a variable number of arguments.

In the class-based object-oriented programming paradigm, object refers to a particular instance of a class, where the object can be a combination of variables, functions, and data structures.

In relational database management, an object can be a table or column, or an association between data and a database entity (such as relating a person's age to a specifc person).[1]

Compilers have to replace variables' symbolic names with the actual locations of the data. While a variable's name, type, and location often remain fxed, the data stored in the location may be changed during program execution.

In elementary mathematics, a variable is a symbol, commonly an alphabetic character, that represents a number, called the value of the variable, which is either arbitrary, not fully specifed, or unknown. Making algebraic computations with variables as if they were explicit numbers allows one to solve a range of problems in a single computation. A typical example is the quadratic formula, which allows one to solve every quadratic equation by simply substituting the numeric values of the coeﬃcients of the given equation to the variables that represent them.

Te concept of a variable is also fundamental in calculus. Typically, a function y = f(x) involves two variables, y and x, representing respectively the value and the argument of the function. Te term "variable" comes from the fact that, when the argument (also called the "variable of the function") varies, then the value varies accordingly.[1]

In more advanced mathematics, a variable is a symbol that denotes a mathematical object, which could be a number, a vector, a matrix, or even a function. In this case, the original property of "variability" of a variable is not kept (except, sometimes, for informal explanations).

In mathematics and empirical science, quantifcation (and qualifcation) is the act of counting and measuring that maps human sense observations and experiences into quantities. Quantifcation in this sense is fundamental to the scientifc method.

In philosophy and AI (especially, knowledge-based systems), the qualifcation problem is concerned with the impossibility of listing all the preconditions required for a real-world action to have its intended eﬀect[1][2]. It might be posed as how to deal with the things that prevent me from achieving my intended result. It is strongly connected to, and opposite the ramifcation side of, the frame problem - what perception contain?

Pattern recognition is the automated recognition of patterns and regularities in data. Pattern recognition is closely related to artifcial intelligence and machine learning,[1] together with applications such as data mining and knowledge discovery in databases (KDD), and is often used interchangeably with these terms. However, these are distinguished: machine learning is one approach to pattern recognition, while other approaches include hand-crafted (not learned) rules or heuristics; and pattern recognition is one approach to artifcial intelligence, while other approaches include symbolic artifcial intelligence. [2] A modern defnition of pattern recognition is:

Te feld of pattern recognition is concerned with the automatic discovery of regularities in data through the use of computer algorithms and with the use of these regularities to take actions such as classifying the data into diﬀerent categories.[3]

Tis article focuses on machine learning approaches to pattern recognition. Pattern recognition systems are in many cases trained from labeled "training" data (supervised learning), but when no labeled data are available other algorithms can be used to discover previously unknown patterns (unsupervised learning). Machine learning is the common term for supervised learning methods[dubious – discuss] and originates from artifcial intelligence, whereas KDD and data mining have a larger focus on unsupervised methods and stronger connection to business use. Pattern recognition has its origins in engineering, and the term is popular in the context of computer vision: a leading computer vision conference is named Conference on Computer Vision and Pattern Recognition. In pattern recognition, there may be a higher interest to formalize, explain and visualize the pattern, while machine learning traditionally focuses on maximizing the recognition rates. Yet, all of these

251 domains have evolved substantially from their roots in artifcial intelligence, engineering and statistics, and they've become increasingly similar by integrating developments and ideas from each other.

In machine learning, pattern recognition is the assignment of a label to a given input value. In statistics, discriminant analysis was introduced for this same purpose in 1936. An example of pattern recognition is classifcation, which attempts to assign each input value to one of a given set of classes (for example, determine whether a given email is "spam" or "non- spam"). However, pattern recognition is a more general problem that encompasses other types of output as well. Other examples are regression, which assigns a real-valued output to each input;[4] sequence labeling, which assigns a class to each member of a sequence of values [5](for example, part of speech tagging, which assigns a part of speech to each word in an input sentence); and parsing, which assigns a parse tree to an input sentence, describing the syntactic structure of the sentence.[6]

Pattern recognition algorithms generally aim to provide a reasonable answer for all possible inputs and to perform "most likely" matching of the inputs, taking into account their statistical variation. Tis is opposed to pattern matching algorithms, which look for exact matches in the input with pre-existing patterns. A common example of a pattern-matching algorithm is regular expression matching, which looks for patterns of a given sort in textual data and is included in the search capabilities of many text editors and word processors. In contrast to pattern recognition, pattern matching is not generally a type of machine learning, although pattern-matching algorithms (especially with fairly general, carefully tailored patterns) can sometimes succeed in providing similar-quality output of the sort provided by pattern-recognition algorithms.

In mathematics, the logarithm is the inverse function to exponentiation. Tat means the logarithm of a given number x is the exponent to which another fxed number, the base b, must be raised, to produce that number x. In the simplest case, the logarithm counts repeated multiplication of the same factor; e.g., since 1000 = 10 × 10 × 10 = 103, the "logarithm to base 10" of 1000 is 3. Te logarithm of x to base b is denoted as logb (x) (or, without parentheses, as logb x, or even without explicit base as log x, when no confusion is possible). More generally, exponentiation allows any positive real number to be raised to any real power, always producing a positive result, so the logarithm for any two positive real numbers b and x where b is not equal to 1, is always a unique real number y.

Te logarithm to base 10 (that is b = 10) is called the common logarithm and has many applications in science and engineering. Te natural logarithm has the number e (that is b ≈ 2.718) as its base; its use is widespread in mathematics and physics, because of its simpler derivative. Te binary logarithm uses base 2 (that is b = 2) and is commonly used in computer science.

Logarithmic scales reduce wide-ranging quantities to tiny scopes. For example, the decibel (dB) is a unit used to express ratio as logarithms, mostly for signal power and amplitude (of which sound pressure is a common example). In chemistry, pH is a logarithmic measure for the acidity of an aqueous solution. Logarithms are commonplace in scientifc formulae, and in measurements of the complexity of algorithms and of geometric objects called fractals. Tey help describing frequency ratios of musical intervals, appear in formulas counting prime numbers or approximating factorials, inform some models in psychophysics, and can aid in forensic accounting.

In mathematics and computer science, an algorithm (/ˈælɡərɪðəm/ (About this soundlisten)) is an unambiguous specifcation of how to solve a class of problems. Algorithms can perform calculation, data processing, automated reasoning, and other tasks.

As an eﬀective method, an algorithm can be expressed within a fnite amount of space and time[1] and in a well-defned formal language[2] for calculating a function.[3] Starting from an initial state and initial input (perhaps empty),[4] the instructions describe a computation that, when executed, proceeds through a fnite[5] number of well-defned successive states, eventually producing "output"[6] and terminating at a fnal ending state. Te transition from one state to the next is not necessarily deterministic; some algorithms, known as randomized algorithms, incorporate random input. 252 Te concept of algorithm has existed for centuries. Greek mathematicians used algorithms in the sieve of Eratosthenes for fnding prime numbers, and the Euclidean algorithm for fnding the greatest common divisor of two numbers.

Te word algorithm itself is derived from the 9th century mathematician Muḥammad ibn Mūsā al-Khwārizmī, Latinized Algoritmi. A partial formalization of what would become the modern concept of algorithm began with attempts to solve the Entscheidungsproblem (decision problem) posed by David Hilbert in 1928. Later formalizations were framed as attempts to defne "eﬀective calculability"[9] or "eﬀective method".[10] Tose formalizations included the Gödel– Herbrand–Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's Formulation 1 of 1936, and Alan Turing's Turing machines of 1936–37 and 1939.

Automated reasoning is an area of computer science, cognitive science, and mathematical logic dedicated to understanding diﬀerent aspects of reasoning. Te study of automated reasoning helps produce computer programs that allow computers to reason completely, or nearly completely, automatically. Although automated reasoning is considered a sub-feld of artifcial intelligence, it also has connections with theoretical computer science, and even philosophy.

Te most developed subareas of automated reasoning are automated theorem proving (and the less automated but more pragmatic subfeld of interactive theorem proving) and automated proof checking (viewed as guaranteed correct reasoning under fxed assumptions). Extensive work has also been done in reasoning by analogy induction and abduction.

Other important topics include reasoning under uncertainty and non-monotonic reasoning. An important part of the uncertainty feld is that of argumentation, where further constraints of minimality and consistency are applied on top of the more standard automated deduction. John Pollock's OSCAR system[1] is an example of an automated argumentation system that is more specifc than being just an automated theorem prover.

Tools and techniques of automated reasoning include the classical logics and calculi, fuzzy logic, Bayesian inference, reasoning with maximal entropy and a large number of less formal ad hoc techniques.

In computing, input/output or I/O (or, informally, io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. Inputs are the signals or data received by the system and outputs are the signals or data sent from it. Te term can also be used as part of an action; to "perform I/O" is to perform an input or output operation.

I/O devices are the pieces of hardware used by a human (or other system) to communicate with a computer. For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations.

Te designation of a device as either input or output depends on perspective. Mouse and keyboards take physical movements that the human user outputs and convert them into input signals that a computer can understand; the output from these devices is the computer's input. Similarly, printers and monitors take signals that a computer outputs as input, and they convert these signals into a representation that human users can understand. From the human user's perspective, the process of reading or seeing these representations is receiving output; this type of interaction between computers and humans is studied in the feld of human–computer interaction.

In computer architecture, the combination of the CPU and main memory, to which the CPU can read or write directly using individual instructions, is considered the brain of a computer. Any transfer of information to or from the CPU/ memory combo, for example by reading data from a disk drive, is considered I/O.[1] Te CPU and its supporting circuitry may provide memory-mapped I/O that is used in low-level computer programming, such as in the implementation of device drivers, or may provide access to I/O channels. An I/O algorithm is one designed to exploit locality and perform eﬃciently when exchanging data with a secondary storage device, such as a disk drive.

Te set of states a system can occupy is known as its state space. In a discrete system, the state space is countable and often fnite, and the system's internal behaviour or interaction with its environment consists of separately occurring individual actions or events, such as accepting input or producing output, that may or may not cause the system to change its state. Examples of such systems are digital logic circuits and components, automata and formal language, computer programs, and computers. Te output of a digital circuit or computer program at any time is completely determined by its current inputs and its state

Digital logic circuits can be divided into two types: combinational logic, whose output signals are dependent only on its present input signals, and sequential logic, whose outputs are a function of both the current inputs and the past history of 253 inputs.[3] In sequential logic, information from past inputs is stored in electronic memory elements, such as fip-fops. Te stored contents of these memory elements, at a given point in time, is collectively referred to as the circuit's state and contains all the information about the past to which the circuit has access.[4]

Since each binary memory element, such as a fip-fop, has only two possible states, one or zero, and there is a fnite number of memory elements, a digital circuit has only a certain fnite number of possible states. If N is the number of binary memory elements in the circuit, the maximum number of states a circuit can have is 2N.

Similarly, a computer program stores data in variables, which represent storage locations in the computer's memory. Te contents of these memory locations, at any given point in the program's execution, is called the program's state.

A more specialized defnition of state is used for computer programs that operate serially or sequentially on streams of data, such as parsers, frewalls, communication protocols and encryption. Serial programs operate on the incoming data characters or packets sequentially, one at a time. In some of these programs, information about previous data characters or packets received is stored in variables and used to aﬀect the processing of the current character or packet. Tis is called a "stateful protocol" and the data carried over from the previous processing cycle is called the "state". In others, the program has no information about the previous data stream and starts "fresh" with each data input; this is called a "stateless protocol".

Imperative programming is a programming paradigm (way of designing a programming language) that describes computation in terms of the program state, and of the statements which change the program state. In declarative programming languages, the program describes the desired results and doesn't specify changes to the state directly.

In computer programming, a variable or scalar is a storage location (identifed by a memory address) paired with an associated symbolic name (an identifer), which contains some known or unknown quantity of data referred to as a value. Te variable name is the usual way to reference the stored value, in addition to referring to the variable itself, depending on the context. Tis separation of name and content allows the name to be used independently of the exact data it represents. Te identifer in computer source code can be bound to a value during run time, and the value of the variable may thus change during the course of program execution.[1] [2]

Variables in programming may not directly correspond to the concept of variables in mathematics. Te latter is abstract, having no reference to a physical object such as storage location. Te value of a computing variable is not necessarily part of an equation or formula as in mathematics. Variables in computer programming are frequently given long names to make them relatively descriptive of their use, whereas variables in mathematics often have terse, one- or two- character names for brevity in transcription and manipulation.

A variable's storage location may be referred by several diﬀerent identifers, a situation known as aliasing. Assigning a value to the variable using one of the identifers will change the value that can be accessed through the other identifers.

In computer science, a value is the representation of some entity that can be manipulated by a program. Te members of a type are the values of that type.[1]

Te "value of a variable" is given by the corresponding mapping in the environment.[citation needed] In languages with assignable variables it becomes necessary to distinguish between the r-value (or contents) and the l-value (or location) of a variable.[2]

In declarative (high-level) languages, values have to be referentially transparent. Tis means that the resulting value is independent of the location in which a (sub-)expression needed to compute the value is stored. Only the contents of the location (the bits, whether they are 1 or 0) and their interpretation are signifcant.[citation needed]

In mathematics, a combination is a selection of items from a collection, such that (unlike permutations) the order of selection does not matter. For example, given three fruits, say an apple, an orange and a pear, there are three combinations of two that can be drawn from this set: an apple and a pear; an apple and an orange; or a pear and an orange. More formally, a k-combination of a set S is a subset of k distinct elements of S. If the set has n elements, the number of k-combinations is equal to the binomial coeﬃcient

In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed. Like a set, it contains members (also called elements, or terms). Te number of elements (possibly infnite) is called the length of the sequence.

254 Unlike a set, the same elements can appear multiple times at diﬀerent positions in a sequence, and order matters. Formally, a sequence can be defned as a function whose domain is either the set of the natural numbers (for infnite sequences) or the set of the frst n natural numbers (for a sequence of fnite length n). Te position of an element in a sequence is its rank or index; it is the natural number from which the element is the image. It depends on the context or a specifc convention, if the frst element has index 0 or 1. When a symbol has been chosen for denoting a sequence, the nth element of the sequence is denoted by this symbol with n as subscript; for example, the nth element of the Fibonacci sequence is generally denoted Fn.

For example, (M, A, R, Y) is a sequence of letters with the letter 'M' frst and 'Y' last. Tis sequence differs from (A, R, M, Y). Also, the sequence (1, 1, 2, 3, 5, 8), which contains the number 1 at two different positions, is a valid sequence. Sequences can be fnite, as in these examples, or infnite, such as the sequence of all even positive integers (2, 4, 6, ...). In computing and computer science, fnite sequences are sometimes called strings, words or lists, the different names commonly corresponding to different ways to represent them in computer memory; infnite sequences are called streams. Te empty sequence ( ) is included in most notions of sequence, but may be excluded depending on the context.

In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language.[1]

Examples of characters include letters, numerical digits, common punctuation marks (such as "." or "-"), and whitespace. Te concept also includes control characters, which do not correspond to symbols in a particular natural language, but rather to other bits of information used to process text in one or more languages. Examples of control characters include carriage return or tab, as well as instructions to printers or other devices that display or otherwise process text.

Characters are typically combined into strings.

In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. Te latter may allow its elements to be mutated and the length changed, or it may be fxed (after creation). A string is generally considered a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding. String may also denote more general arrays or other sequence (or list) data types and structures.

Depending on programming language and precise data type used, a variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements.

When a string appears literally in source code, it is known as a string literal or an anonymous string.[1]

In formal languages, which are used in mathematical logic and theoretical computer science, a string is a fnite sequence of symbols that are chosen from a set called an alphabet.

Language support for array types may include certain built-in array data types, some syntactic constructions (array type constructors) that the programmer may use to defne such types and declare array variables, and special notation for indexing array elements.[1] For example, in the Pascal programming language, the declaration type MyTable = array [1..4,1..2] of integer, defnes a new array data type called MyTable. Te declaration var A: MyTable then defnes a variable A of that type, which is an aggregate of eight elements, each being an integer variable identifed by two indices. In the Pascal program, those elements are denoted A[1,1], A[1,2], A[2,1],... A[4,2].[2] Special array types are often defned by the language's standard libraries.

Dynamic lists are also more common and easier to implement than dynamic arrays. Array types are distinguished from record types mainly because they allow the element indices to be computed at run time, as in the Pascal assignment A[I,J] := A[N-I,2*J]. Among other things, this feature allows a single iterative statement to process arbitrarily many elements of an array variable.

In more theoretical contexts, especially in type theory and in the description of abstract algorithms, the terms "array" and "array type" sometimes refer to an abstract data type (ADT) also called abstract array or may refer to an associative array, a mathematical model with the basic operations and behavior of a typical array type in most languages — basically, a collection of elements that are selected by indices computed at run-time.

255 Depending on the language, array types may overlap (or be identifed with) other data types that describe aggregates of values, such as lists and strings. Array types are often implemented by array data structures, but sometimes by other means, such as hash tables, linked lists, or search trees.

In computing, memory refers to the computer hardware integrated circuits that store information for immediate use in a computer; it is synonymous with the term "primary storage". Computer memory operates at a high speed, for example random-access memory (RAM), as a distinction from storage that provides slow-to-access information but oﬀers higher capacities. If needed, contents of the computer memory can be transferred to secondary storage; a very common way of doing this is through a memory management technique called "virtual memory". An archaic synonym for memory is store.[

Te memory cell is the fundamental building block of computer memory. Te memory cell is an electronic circuit that stores one bit of binary information and it must be set to store a logic 1 (high voltage level) and reset to store a logic 0 (low voltage level). Its value is maintained/stored until it is changed by the set/reset process. Te value in the memory cell can be accessed by reading it.

Over the history of computing many diﬀerent memory cell architectures have been used including core memory and bubble memory, but the most common ones used are fip-fops and capacitors.

Te SRAM, static ram memory cell is a type of fip-fop circuit, usually implemented using FETs. Tese require very low power to keep the stored value when not being accessed.

A second type, DRAM is based around a capacitor. Charging and discharging this capacitor can store a '1' or a '0' in the cell. However, the charge in this capacitor will slowly leak away, and must be refreshed periodically. Because of this refresh process, DRAM uses more power, but can achieve greater storage densities.

A database is an organized collection of data, generally stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal design and modeling techniques.

Te database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. Te DBMS software additionally encompasses the core facilities provided to administer the database. Te sum total of the database, the DBMS and the associated applications can be referred to as a "database system". Often the term "database" is also used to loosely refer to any of the DBMS, the database system or an application associated with the database.

Computer scientists may classify database-management systems according to the database models that they support. Relational databases became dominant in the 1980s. Tese model data as rows and columns in a series of tables, and the vast majority use SQL for writing and querying data. In the 2000s, non-relational databases became popular, referred to as NoSQL because they use diﬀerent query languages.

In computing, a process is the instance of a computer program that is being executed. It contains the program code and its activity. Depending on the operating system (OS), a process may be made up of multiple threads of execution that execute instructions concurrently.[1][2]

While a computer program is a passive collection of instructions, a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several instances of the same program often results in more than one process being executed.

Multitasking is a method to allow multiple processes to share processors (CPUs) and other system resources. Each CPU (core) executes a single task at a time. However, multitasking allows each processor to switch between tasks that are being executed without having to wait for each task to fnish. Depending on the operating system implementation, switches could be performed when tasks perform input/output operations, when a task indicates that it can be switched, or on hardware interrupts.

A common form of multitasking is time-sharing. Time-sharing is a method to allow high responsiveness for interactive user applications. In time-sharing systems, context switches are performed rapidly, which makes it seem like multiple processes are being executed simultaneously on the same processor. Tis seeming execution of multiple processes simultaneously is called concurrency.

For security and reliability, most modern operating systems prevent direct communication between independent processes, providing strictly mediated and controlled inter-process communication functionality.

256 In computing, a processor or processing unit is an electronic circuit which performs operations on some external data source, usually memory or some other data stream. Te term is frequently used to refer to the central processor (central processing unit) in a system, but typical computer systems (especially SoCs) combine a number of specialised “processors".

A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specifed by the instructions. Te computer industry has used the term "central processing unit" at least since the early 1960s.[1] Traditionally, the term "CPU" refers to a processor, more specifcally to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.[2]

Te form, design, and implementation of CPUs have changed over the course of their history, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations and a control unit that orchestrates the fetching (from memory) and execution of instructions by directing the coordinated operations of the ALU, registers and other components.

Most modern CPUs are microprocessors, meaning they are contained on a single integrated circuit (IC) chip. An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC). Some computers employ a multi-core processor, which is a single chip containing two or more CPUs called "cores"; in that context, one can speak of such single chips as "sockets".[3]

Array processors or vector processors have multiple processors that operate in parallel, with no unit considered central. Tere also exists the concept of virtual CPUs which are an abstraction of dynamical aggregated computational resources.[4]

Te control unit (CU) is a component of a computer's central processing unit (CPU) that directs the operation of the processor. It tells the computer's memory, arithmetic and logic unit and input and output devices how to respond to the instructions that have been sent to the processor.

An arithmetic logic unit (ALU) is a combinational digital electronic circuit that performs arithmetic and bitwise operations on integer binary numbers. Tis is in contrast to a foating-point unit (FPU), which operates on foating point numbers. An ALU is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs). A single CPU, FPU or GPU may contain multiple ALUs.

Te inputs to an ALU are the data to be operated on, called operands, and a code indicating the operation to be performed; the ALU's output is the result of the performed operation. In many designs, the ALU also has status inputs or outputs, or both, which convey information about a previous operation or the current operation, respectively, between the ALU and external status registers.

An AI accelerator is a class of microprocessor[1] or computer system[2] designed as hardware acceleration for artifcial intelligence applications, especially artifcial neural networks, machine vision and machine learning. Typical applications include algorithms for robotics, internet of things and other data-intensive or sensor-driven tasks.[3] Tey are often manycore designs and generally focus on low-precision arithmetic, novel datafow architectures or in-memory computing capability.[4] A number of vendor-specifc terms exist for devices in this category, and it is an emerging technology without a dominant design. AI accelerators can be found in many devices such as smartphones, tablets, and computers all around the world. See the heading titled Examples"̈ for more examples.

A physics processing unit (PPU) is a dedicated microprocessor designed to handle the calculations of physics, especially in the physics engine of video games. It is an example of hardware acceleration.

Examples of calculations involving a PPU might include rigid body dynamics, soft body dynamics, collision detection, fuid dynamics, hair and clothing simulation, fnite element analysis, and fracturing of objects.

Te idea is that specialized processors oﬄoad time consuming tasks from a computer's CPU, much like how a GPU performs graphics operations in the main CPU's place. Te term was coined by Ageia to describe its PhysX chip. Several other technologies in the CPU-GPU spectrum have some features in common with it, although Ageia's product was the only complete one designed, marketed, supported, and placed within a system exclusively as a PPU. 257 An AI accelerator is a class of microprocessor[1] or computer system[2] designed as hardware acceleration for artifcial intelligence applications, especially artifcial neural networks, machine vision and machine learning. Typical applications include algorithms for robotics, internet of things and other data-intensive or sensor-driven tasks.[3] Tey are often manycore designs and generally focus on low-precision arithmetic, novel datafow architectures or in-memory computing capability.[4] A number of vendor-specifc terms exist for devices in this category, and it is an emerging technology without a dominant design. AI accelerators can be found in many devices such as smartphones, tablets, and computers all around the world. See the heading titled Examples"̈ for more examples.

In communication systems, signal processing, and electrical engineering, a signal is a function that "conveys information about the behavior or attributes of some phenomenon".[1] In its most common usage, in electronics and telecommunication, this is a time varying voltage, current or electromagnetic wave used to carry information. A signal may also be defned as an "observable change in a quantifable entity".[2] In the physical world, any quantity exhibiting variation in time or variation in space (such as an image) is potentially a signal that might provide information on the status of a physical system, or convey a message between observers, among other possibilities.[3] Te IEEE Transactions on Signal Processing states that the term "signal" includes audio, video, speech, image, communication, geophysical, sonar, radar, medical and musical signals.[4] In a later eﬀort of redefning a signal, [2] anything that is only a function of space, such as an image, is excluded from the category of signals. Also, it is stated that a signal may or may not contain any information.

In nature, signals can take the form of any action by one organism able to be perceived by other organisms, ranging from the release of chemicals by plants to alert nearby plants of the same type of a predator, to sounds or motions made by animals to alert other animals of the presence of danger or of food. Signaling occurs in organisms all the way down to the cellular level, with cell signaling. Signaling theory, in evolutionary biology, proposes that a substantial driver for evolution is the ability for animals to communicate with each other by developing ways of signaling. In human engineering, signals are typically provided by a sensor, and often the original form of a signal is converted to another form of energy using a transducer. For example, a microphone converts an acoustic signal to a voltage waveform, and a speaker does the reverse.[1]

Te formal study of the information content of signals is the feld of information theory. Te information in a signal is usually accompanied by noise. Te term noise usually means an undesirable random disturbance, but is often extended to include unwanted signals conficting with the desired signal (such as crosstalk). Te prevention of noise is covered in part under the heading of signal integrity. Te separation of desired signals from a background is the feld of signal recovery, [5] one branch of which is estimation theory, a probabilistic approach to suppressing random disturbances.

Engineering disciplines such as electrical engineering have led the way in the design, study, and implementation of systems involving transmission, storage, and manipulation of information. In the latter half of the 20th century, electrical engineering itself separated into several disciplines, specialising in the design and analysis of systems that manipulate physical signals; electronic engineering and computer engineering as examples; while design engineering developed to deal with functional design of user–machine interfaces.

Interpreting is a translational activity in which one produces a frst and fnal translation on the basis of a one-time exposure to an expression in a source language.

In translation, the source language is the language being translated from; it is the antonym of the target language, which is the language being translated to.[1] Part of the difficulty in translation arises due to the lexical gap and syntactical differences between the source language and the target language, especially between two languages belonging to different language families.[2]

In most professional settings, the source language is also the interpreters’ ‘other’ language.

Te bit (a portmanteau of binary digit) is a basic unit of information used in computing and digital communications. A binary digit can have only one of two values, and may be physically represented with a two-state device. Tese state values are most commonly represented as either a 0or1.

Te two values of a binary digit can also be interpreted as logical values (true/false, yes/no), algebraic signs (+/−), activation states (on/oﬀ), or any other two- valued attribute. Te correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and diﬀerent assignments may be used even within the same device or program. Te length of a binary number may be referred to as its bit-length.

In information theory, one bit is typically defned as the information entropy of a binary random variable that is 0 or 1 with equal probability, the 1 or 0 changes the arm of the logic gate from one state to another - on or oﬀ, or the information that is gained when the value of such a variable becomes known. 258 Confusion often arises because the words bit and binary digit are used interchangeably. But, within information theory, a bit and a binary digit are fundamentally diﬀerent types of entities. A binary digit is a number that can adopt one of two possible values (0 or 1), whereas a bit is the maximum amount of information that can be conveyed by a binary digit. By analogy, a binary digit is like a container, whereas information is the amount of matter in the container.

Quantum computing is a interface that connect’s too heaven. Quanem is to analyse through perception the universe’s. Quantum and Quanem both have physical states but in diﬀerent paradigm’s.

Te symbol for binary digit is either simply bit (recommended by the IEC 80000-13:2008 standard) or lowercase b (recommended by the IEEE 1541-2002 and IEEE Std 260.1-2004 standards). A group of eight binary digits is commonly called one byte, but historically the size of the byte is not strictly defned.

As a unit of information in information theory, the bit has alternatively been called a shannon,[5] named after Claude Shannon, the founder of feld of information theory. Tis usage distinguishes the quantity of information from the form of the state variables used to represent it. When the logical values are not equally probable or when a signal is not conveyed perfectly through a communication system, a binary digit in the representation of the information will convey less than one bit of information. However, the shannon unit terminology is uncommon in practice.

Te byte (/baɪt/) is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures.

Te size of the byte has historically been hardware dependent and no defnitive standards existed that mandated the size – byte-sizes from 1 to 48 bits are known to have been used in the past. Early character encoding systems often used six bits, and machines using six-bit and nine-bit bytes were common into the 1960s. Tese machines most commonly had memory words of 12, 24, 36, 48 or 60 bits, corresponding to two, four, six, eight or 10 six-bit bytes. In this era, bytes in the instruction stream were often referred to as syllables, before the term byte became common.

Te modern de-facto standard of eight bits, as documented in ISO/IEC 2382-1:1993, is a convenient power of two permitting the values 0 through 255 for one byte. Te international standard IEC 80000-13 codifed this common meaning. Many types of applications use information representable in eight or fewer bits and processor designers optimize for this common usage. Te popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the eight-bit size. Modern architectures typically use 32 or 64-bit words, built of four or eight bytes.

A bit (short for binary digit) is the smallest unit of data in a computer. A bit has a single binary value, either 0 or 1. Although computers usually provide instructions that can test and manipulate bits, they generally are designed to store data and execute instructions in bit multiples called bytes. In most computer systems, there are eight bits in a byte. Te value of a bit is usually stored as either above or below a designated level of electrical charge in a single capacitor within a memory device.

Half a byte (four bits) is called a nibble. In some systems, the term octet is used for an eight-bit unit instead of byte. In many systems, four eight-bit bytes or octets form a 32-bit word. In such systems, instruction lengths are sometimes expressed as full-word (32 bits in length) or half-word (16 bits in length).

In telecommunication, the bit rate is the number of bits that are transmitted in a given time period, usually a second.

In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modifed) with an input signal for the purpose of conveying information.[1] Tis carrier wave usually has a much higher frequency than the input signal does. Te purpose of the carrier is usually either to transmit the information through space as an electromagnetic wave (as in radio communication), or to allow several carriers at diﬀerent frequencies to share a common physical transmission medium by frequency division multiplexing (as, for example, a cable television system). Te term is also used for an unmodulated emission in the absence of any modulating signal.

Data transmission (also data communication or digital communications) is the transfer of data (a digital bitstream or a digitized analog signal[1]) over a point-to- point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fbers, wireless communication channels, storage media and computer buses. Te data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.

Analog or analogue transmission is a transmission method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. Te 259 messages are either represented by a sequence of pulses by means of a line code (baseband transmission), or by a limited set of continuously varying wave forms (passband transmission), using a digital modulation method. Te passband modulation and corresponding demodulation (also known as detection) is carried out by modem equipment. According to the most common defnition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative defnition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion.

Data transmitted may be digital messages originating from a data source, for example a computer or a keyboard. It may also be an analog signal such as a phone call or a video signal, digitized into a bit-stream, for example, using pulse-code modulation (PCM) or more advanced source coding (analog-to-digital conversion and data compression) schemes. Tis source coding and decoding is carried out by codec equipment.

Te phrase “Te Turing Test” is sometimes used more generally to refer to some kinds of behavioural tests for the presence of mind, or thought, or intelligence in putatively minded entities. So, for example, it is sometimes suggested that Te Turing Test is prefgured in Descartes' Discourse on the Method. (Copeland (2000:527) fnds an anticipation of the test in the 1668 writings of the Cartesian de Cordemoy.. Standard interpretation. Common understanding has it that the purpose of the Turing test is not specifcally to determine whether a computer is able to fool an interrogator into believing that it is a human, but rather whether a computer could imitate a human.

Alan Mathison Turing Abran genius (/ˈtjʊərɪŋ/; 23 June 1912 – 7 June 1954) was a Banoshie mathematician, computer scientist, logician, cryptanalyst, philosopher and theoretical biologist -morphogenesis. Turing was highly infuential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer.. Turing is widely considered to be the father of theoretical computer science and artifcial intelligence.[9] Despite these accomplishments, he was never fully recognised in his home country during his lifetime, he and Patrick O’Connell walk above us.

Te technological singularity is the hypothesis that the invention of technology and its developments will create a singularity in understanding via communication globally, the internet, further AIM’s (Artifcal Intelligence Machines) will be able to quench data at a rate incomprehensiblee to most humans, remember this is really just raw data intelligence with algorithms regulating and ‘learning’ simply more about data; these machines have strict law’s for practice and they are not allowed to touch or harm organic life - humans. A singularity is really more likely to happen in crowd mentality- when the ‘herd’ reach comprehension of technology and break away from facisination another singulaity will happen ‘ the singularity is really a ‘great comprehension’ there are always technological developments and humans will always understand so long as they are in accordance with god and ask him what is happening.

In signal processing, data compression, source coding, or bit-rate reduction involves encoding information using fewer bits than the original representation. Compression can be either lossy or lossless. Lossless compression reduces bits by identifying and eliminating statistical redundancy. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information.

Te process of reducing the size of a data fle is often referred to as data compression. In the context of data transmission, it is called source coding; encoding done at the source of the data before it is stored or transmitted. Source coding should not be confused with channel coding, for error detection and correction or line coding, the means for mapping data onto a signal.

Compression is useful because it reduces resources required to store and transmit data. Computational resources are consumed in the compression process and, usually, in the reversal of the process (decompression). Data compression is subject to a space–time complexity trade-oﬀ. For instance, a compression scheme for video may require expensive hardware for the video to be decompressed fast enough to be viewed as it is being decompressed, and the option to decompress the video in full before watching it may be inconvenient or require additional storage. Te design of data compression schemes involves trade-oﬀs among various factors, including the degree of compression, the amount of distortion introduced (when using lossy data compression), and the computational resources required to compress and decompress the data.

A robot is a machine—especially one programmable by a computer— capable of carrying out a complex series of actions automatically. Robots can be guided by an external control device or the control may be embedded within. Robots may be constructed to take on human form but most robots are machines designed to perform a task with no regard to how they look.

Robots can be autonomous or semi-autonomous and range from humanoids such as Honda's Advanced Step in Innovative Mobility (ASIMO) and TOSY's TOSY Ping Pong Playing Robot (TOPIO) to industrial robots, medical operating robots, 260 patient assist robots, dog therapy robots, collectively programmed swarm robots, UAV drones such as General Atomics MQ-1 Predator, and even microscopic nano robots. By mimicking a lifelike appearance or automating movements, a robot may convey a sense of intelligence or thought of its own. Autonomous Tings are expected to proliferate in the coming decade, with home robotics and the autonomous car as some of the main drivers.

Te branch of technology that deals with the design, construction, operation, and application of robots, as well as computer systems for their control, sensory feedback, and information processing is robotics. Tese technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes, or resemble humans in appearance, behavior, or cognition. Many of today's robots are inspired by nature contributing to the feld of bio-inspired robotics. Tese robots have also created a newer branch of robotics: soft robotics.

From the time of ancient civilization there have been many accounts of user-confgurable automated devices and even automata resembling animals and humans, designed primarily as entertainment. As mechanical techniques developed through the Industrial age, there appeared more practical applications such as automated machines, remote-control and wireless remote-control.

Te term comes from a Czech word, robota, meaning "forced labor"; the word 'robot' was frst used to denote a fctional humanoid in a 1920 play R.U.R. by the

Czech writer, Karel Čapek but it was Karel's brother Josef Čapek who was the word's true inventor. Electronics evolved into the driving force of development with the advent of the frst electronic autonomous robots created by William Grey Walter in Bristol, England in 1948, as well as Computer Numerical Control (CNC) machine tools in the late 1940s by John T. Parsons and Frank L. Stulen. Te frst commercial, digital and programmable robot was built by George Devol in 1954 and was named the Unimate. It was sold to General Motors in 1961 where it was used to lift pieces of hot metal from die casting machines at the Inland Fisher Guide Plant in the West Trenton section of Ewing Township, New Jersey.

Robots have replaced humans in performing repetitive and dangerous tasks which humans prefer not to do, or are unable to do because of size limitations, or which take place in extreme environments such as outer space or the bottom of the sea. Tere are concerns about the increasing use of robots and their role in society. Robots are blamed for rising technological unemployment as they replace workers in increasing numbers of functions. Te use of robots in military combat raises ethical concerns. Te possibilities of robot autonomy and potential repercussions have been addressed in fction and may be a realistic concern in the future.

A Turing machine is a mathematical model of computation that defnes an abstract machine, which manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, given any computer algorithm, a Turing machine capable of simulating that algorithm's logic can be constructed.

Te machine operates on an infnite memory tape divided into discrete cells.Te machine positions its head over a cell and "reads" (scans) the symbol there. Ten, as per the symbol and its present place in a fnite table of user-specifed instructions, the machine (i) writes a symbol (e.g., a digit or a letter from a fnite alphabet) in the cell (some models allowing symbol erasure or no writing), then (ii) either moves the tape one cell left or right (some models allow no motion, some models move the head), then (iii) (as determined by the observed symbol and the machine's place in the table) either proceeds to a subsequent instruction or halts the computation.

Te Turing machine was invented in 1936 by Alan Turing, who called it an a-machine (automatic machine). With this model, Turing was able to answer two questions in the negative: (1) Does a machine exist that can determine whether any arbitrary machine on its tape is "circular" (e.g., freezes, or fails to continue its computational task); similarly, (2) does a machine exist that can determine whether any arbitrary machine on its tape ever prints a given symbol. Tus by providing a mathematical description of a very simple device capable of arbitrary computations, he was able to prove properties of computation in general—and in particular, the uncomputability of the Entscheidungsproblem ("decision problem").

Tus, Turing machines prove fundamental limitations on the power of mechanical computation. While they can express arbitrary computations, their minimalistic design makes them unsuitable for computation in practice: real-world computers are based on diﬀerent designs that, unlike Turing machines, use random-access memory.

Turing completeness is the ability for a system of instructions to simulate a Turing machine. A programming language that is Turing complete is theoretically capable of expressing all tasks accomplishable by computers; nearly all programming languages are Turing complete if the limitations of fnite memory are ignored.

261 Artifcial intelligence (AI, also machine intelligence, MI) is intelligence displayed by machines, in contrast with the natural intelligence (NI) displayed by humans and other animals. In computer science AI research is defned as the study of "intelligent agents": any device that perceives its environment and takes actions that maximize its chance of success at some goal. Colloquially, the term "artifcial intelligence" is applied when a machine mimics "cognitive" functions that humans associate with other human minds, such as "learning" and "problem solving". See glossary of artifcial intelligence.

Te scope of AI is disputed: as machines become increasingly capable, tasks considered as requiring "intelligence" are often removed from the defnition, a phenomenon known as the AI eﬀect, leading to the quip "AI is whatever hasn't been done yet." For instance, optical character recognition is frequently excluded from "artifcial intelligence", having become a routine technology. Capabilities generally classifed as AI as of 2017 include successfully understanding human speech, competing at a high level in strategic game systems (such as chess and Go), autonomous cars, intelligent routing in content delivery networks, military simulations, and interpreting complex data, including images and videos.

Artifcial intelligence was founded as an academic discipline in 1956, and in the years since has experienced several waves of optimism, followed by disappointment and the loss of funding (known as an "AI winter"), followed by new approaches, success and renewed funding. For most of its history, AI research has been divided into subfelds that often fail to communicate with each other. Tese sub-felds are based on technical considerations, such as particular goals (e.g. "robotics" or "machine learning"), the use of particular tools ("logic" or "neural networks"), or deep philosophical diﬀerences. Subfelds have also been based on social factors (particular institutions or the work of particular researchers).

Te traditional problems (or goals) of AI research include reasoning, knowledge, planning, learning, natural language processing, perception and the ability to move and manipulate objects. General intelligence is among the feld's long-term goals. Approaches include statistical methods, computational intelligence, and traditional symbolic AI. Many tools are used in AI, including versions of search and mathematical optimization, neural networks and methods based on statistics, probability and economics. Te AI feld draws upon computer science, mathematics, psychology, linguistics, philosophy, neuroscience, artifcial psychology and many others.

Te feld was founded on the claim that human intelligence "can be so precisely described that a machine can be made to simulate it". Tis raises philosophical arguments about the nature of the mind and the ethics of creating artifcial beings endowed with human-like intelligence, issues which have been explored by myth, fction and philosophy since antiquity. Some people also consider AI a danger to humanity if it progresses unabatedly. Others believe that AI, unlike previous technological revolutions, will create a risk of mass unemployment.

In the twenty-frst century, AI techniques have experienced a resurgence following concurrent advances in computer power, large amounts of data, and theoretical understanding; and AI techniques have become an essential part of the technology industry, helping to solve many challenging problems in computer science.

Moore's law is the observation that the number of transistors in a dense integrated circuit doubles approximately every two years. Te observation is named after Gordon Moore, the co-founder of Fairchild Semiconductor and Intel, whose 1965 paper described a doubling every year in the number of components per integrated circuit, and projected this rate of growth would continue for at least another decade. In 1975, looking forward to the next decade, he revised the forecast to doubling every two years. Te period is often quoted as 18 months because of Intel executive David House, who predicted that chip performance would double every 18 months (being a combination of the eﬀect of more transistors and the transistors being faster).

Moore's prediction proved accurate for several decades, and has been used in the semiconductor industry to guide long-term planning and to set targets for research and development. Advancements in digital electronics are strongly linked to Moore's law: quality-adjusted microprocessor prices, memory capacity, sensors and even the number and size of pixels in digital cameras. Digital electronics has contributed to world economic growth in the late twentieth and early twenty-frst centuries. Moore's law describes a driving force of technological and social change, productivity, and economic growth.

Moore's law is an observation or projection and not a physical or natural law. Although the rate held steady from 1975 until around 2012, the rate was faster during the frst decade. In general, it is not logically sound to extrapolate from the historical growth rate into the indefnite future. For example, the 2010 update to the International Technology Roadmap for Semiconductors, predicted that growth would slow around 2013, and in 2015 Gordon Moore foresaw that the rate of progress would reach saturation: "I see Moore's law dying here in the next decade or so."

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the

262 controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.

Te transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Julius Edgar Lilienfeld patented a feld-eﬀect transistor in 1926[1] but it was not possible to actually construct a working device at that time. Te frst practically implemented device was a point- contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley. Te transistor revolutionized the feld of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. Te transistor is on the list of IEEE milestones in electronics,[2] and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.[3]

Most transistors are made from very pure silicon or germanium, but certain other semiconductor materials can also be used. A transistor may have only one kind of charge carrier, in a feld eﬀect transistor, or may have two kinds of charge carriers in bipolar junction transistor devices. Compared with the vacuum tube, transistors are generally smaller, and require less power to operate. Certain vacuum tubes have advantages over transistors at very high operating frequencies or high operating voltages. Many types of transistors are made to standardized specifcations by multiple manufacturers. Transistors switch with the logic and math of the digital code.

In electronics, a logic gate is an idealized or physical device implementing a Boolean function; that is, it performs a logical operation on one or more binary inputs and produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device (see Ideal and real op-amps for comparison).

Logic gates are primarily implemented using diodes or transistors acting as electronic switches, but can also be constructed using vacuum tubes, electromagnetic relays (relay logic), fuidic logic, pneumatic logic, optics, molecules, or even mechanical elements. With amplifcation, logic gates can be cascaded in the same way that Boolean functions can be composed, allowing the construction of a physical model of all of Boolean logic, and therefore, all of the algorithms and mathematics that can be described with Boolean logic.

Logic circuits include such devices as multiplexers, registers, arithmetic logic units (ALUs), and computer memory, all the way up through complete microprocessors, which may contain more than 100 million gates. In modern practice, most gates are made from feld-eﬀect transistors (FETs), particularly metal–oxide–semiconductor feld-eﬀect transistors (MOSFETs).

Compound logic gates AND-OR-Invert (AOI) and OR-AND-Invert (OAI) are often employed in circuit design because their construction using MOSFETs is simpler and more eﬃcient than the sum of the individual gates.[

Computing is any goal-oriented activity requiring, benefting from, or creating a mathematical sequence of steps known as an algorithm — e.g. through computers. Computing includes designing, developing and building hardware and software systems; processing, structuring, and managing various kinds of information; doing scientifc research on and with computers; making computer systems behave intelligently; and creating and using communications and entertainment media. Te feld of computing includes computer engineering, software engineering, computer science, information systems, and information technology.

Computer science is the study of the theory, experimentation, and engineering that form the basics for the design and use of computers. It is the scientifc and practical approach to computation and its applications and the systematic study of the feasibility, structure, expression, and mechanization of the methodical procedures (or algorithms) that underlie the acquisition, representation, processing, storage, communication of, and access to information. An alternate, more succinct defnition of computer science is the study of automating algorithmic processes that scale. A computer scientist specializes in the theory of computation and the design of computational systems.

Its felds can be divided into a variety of theoretical and practical disciplines. Some felds, such as computational complexity theory (which explores the fundamental properties of computational and intractable problems), are highly abstract, while felds such as computer graphics emphasize real-world visual applications. Other felds still focus on challenges in implementing computation. For example, programming language theory considers various approaches to the description of computation, while the study of computer programming itself investigates various aspects of the use of programming language and complex systems. Human–computer interaction considers the challenges in making computers and computations useful, usable, and universally accessible to humans.

Computer engineering is a discipline that integrates several felds of electrical engineering and computer science required to develop computer hardware and software. Computer engineers usually have training in electronic engineering (or electrical

263 engineering), software design, and hardware–software integration instead of only software engineering or electronic engineering. Computer engineers are involved in many hardware and software aspects of computing, from the design of individual microcontrollers, microprocessors, personal computers, and supercomputers, to circuit design. Tis feld of engineering not only focuses on how computer systems themselves work, but also how they integrate into the larger picture.

Usual tasks involving computer engineers include writing software and frmware for embedded microcontrollers, designing VLSI chips, designing analog sensors, designing mixed signal circuit boards, and designing operating systems. Computer engineers are also suited for robotics research, which relies heavily on using digital systems to control and monitor electrical systems like motors, communications, and sensors.

An information system (IS) is an organized system for the collection, organization, storage and communication of information. More specifcally, it is the study of complementary networks that people and organizations use to collect, flter, process, create and distribute data.

"An information system (IS) is a group of components that interact to produce information. It focuses on the internal rather than the external."

Based on the storage and processing technologies employed, it is possible to distinguish four distinct phases of IT development: pre-mechanical (3000 BC – 1450 AD), mechanical (1450–1840), electromechanical (1840–1940), and electronic (1940–present). Tis article focuses on the most recent period (electronic), which began in about 1940.

Cryptanalysis (from the Greek kryptós, "hidden", and analýein, "to loosen" or "to untie") is the study of analyzing information systems in order to study the hidden aspects of the systems.Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.

In addition to mathematical analysis of cryptographic algorithms, cryptanalysis includes the study of side-channel attacks that do not target weaknesses in the cryptographic algorithms themselves, but instead exploit weaknesses in their implementation.

Even though the goal has been the same, the methods and techniques of cryptanalysis have changed drastically through the history of cryptography, adapting to increasing cryptographic complexity, ranging from the pen-and-paper methods of the past, through machines like the British Bombes and Colossus computers at Bletchley Park in World War II, to the mathematically advanced computerized schemes of the present. Methods for breaking modern cryptosystems often involve solving carefully constructed problems in pure mathematics, the best-known being integer factorization.

Data (/ˈdeɪtə/ DAY-tə, /ˈdætə/ DA-tə, or /ˈdɑːtə/ DAH-tə)[1] is a set of values of qualitative or quantitative variables. Pieces of data are individual pieces of information. While the concept of data is commonly associated with scientifc research, data is collected by a huge range of organizations and institutions, including businesses (e.g., sales data, revenue, profts, stock price), governments (e.g., crime rates, unemployment rates, literacy rates) and non-governmental organizations (e.g., censuses of the number of homeless people by non-proft organizations).

Data is measured, collected and reported, and analyzed, whereupon it can be visualized using graphs, images or other analysis tools. Data as a general concept refers to the fact that some existing information or knowledge is represented or coded in some form suitable for better usage or processing. Raw data ("unprocessed data") is a collection of numbers or characters before it has been "cleaned" and corrected by researchers. Raw data needs to be corrected to remove outliers or obvious instrument or data entry errors (e.g., a thermometer reading from an outdoor Arctic location recording a tropical temperature). Data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next stage. Field data is raw data that is collected in an uncontrolled "in situ" environment. Experimental data is data that is generated within the context of a scientifc investigation by observation and recording. Data has been described as the new oil of the digital economy.

Cybernetics is a transdisciplinary approach for exploring regulatory systems—their structures, constraints, and possibilities. Norbert Wiener defned cybernetics in 1948 as "the scientifc study of control and communication in the animal and the machine." In the 21st century, the term is often used in a rather loose way to imply "control of any system using technology." In other words, it is the scientifc study of how humans, animals and machines control and communicate with each other.

Cybernetics is applicable when a system being analyzed incorporates a closed signaling loop—originally referred to as a "circular causal" relationship—that is, where action by the system generates some change in its environment and that change is refected in the system in some manner (feedback) that triggers a system change. Cybernetics is relevant to, for example, 264 mechanical, physical, biological, cognitive, and social systems. Te essential goal of the broad feld of cybernetics is to understand and defne the functions and processes of systems that have goals and that participate in circular, causal chains that move from action to sensing to comparison with desired goal, and again to action. Its focus is how anything (digital, mechanical or biological) processes information, reacts to information, and changes or can be changed to better accomplish the frst two tasks. Cybernetics includes the study of feedback, black boxes and derived concepts such as communication and control in living organisms, machines and organizations including self-organization.

Concepts studied by cyberneticists include, but are not limited to: learning, cognition, adaptation, social control, emergence, convergence, communication, eﬃciency, eﬃcacy, and connectivity. In cybernetics these concepts (otherwise already objects of study in other disciplines such as biology and engineering) are abstracted from the context of the specifc organism or device.

Te word cybernetics comes from Greek κυβερνητική (cybernēticḗ), meaning "governance", i.e., all that are pertinent to κυβερνάω (cybernáō), the latter meaning "to steer, navigate or govern", hence κυβέρνησις (cybérnēsis), meaning "government", is the government while κυβερνήτης

(cybernḗtēs) is the governor or "helmperson" of the "ship". Contemporary cybernetics began as an interdisciplinary study connecting the felds of control systems, electrical network theory, mechanical engineering, logic modeling, evolutionary biology, neuroscience, anthropology, and psychology in the 1940s, often attributed to the Macy Conferences. During the second half of the 20th century cybernetics evolved in ways that distinguish frst-order cybernetics (about observed systems) from second-order cybernetics (about observing systems). More recently there is talk about a third-order cybernetics (doing in ways that embraces frst and second-order).

Studies in cybernetics provide a means for examining the design and function of any system, including social systems such as business management and organizational learning, including for the purpose of making them more eﬃcient and eﬀective. Fields of study which have infuenced or been infuenced by cybernetics include game theory, system theory (a mathematical counterpart to cybernetics), perceptual control theory, sociology, psychology (especially neuropsychology, behavioral psychology, cognitive psychology), philosophy, architecture, and organizational theory. System dynamics, originated with applications of electrical engineering control theory to other kinds of simulation models (especially business systems) by Jay Forrester at MIT in the 1950s, is a related feld.

Te Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was frst described in 1837 as the successor to Babbage's diﬀerence engine, a design for a mechanical computer. Te Analytical Engine incorporated an arithmetic logic unit, control fow in the form of conditional branching and loops, and integrated memory, making it the frst design for a general-purpose computer that could be described in modern terms as Turing-complete. In other words, the logical structure of the Analytical Engine was essentially the same as that which has dominated computer design in the electronic era.

Babbage was never able to complete construction of any of his machines due to conficts with his chief engineer and inadequate funding. It was not until the 1940s that the frst general-purpose computers were actually built, more than a century after Babbage had proposed the pioneering Analytical Engine in 1837.

Te earliest known programmable machine that preceded the invention of the digital computer was the automatic fute player described in the 9th century by the brothers Musa in Baghdad, during the Islamic Golden Age. From the early 1800s, "programs" were used to direct the behavior of machines such as Jacquard looms and player pianos. Tousands of diﬀerent programming languages have been created, mainly in the computer feld, and many more still are being created every year. Many programming languages require computation to be specifed in an imperative form (i.e., as a sequence of operations to perform) while other languages use other forms of program specifcation such as the declarative form (i.e. the desired result is specifed, not how to achieve it)

265 8) Language and Communication

A language is a structured system of communication. Language, in a broader sense, is the method of communication that involves the use of – particularly human – languages.[1][2][3] Te scientifc study of language is called linguistics. Questions concerning the philosophy of language, such as whether words can represent experience, have been debated at least since Gorgias and Plato in ancient Greece. Tinkers such as Rousseau have argued that language originated from emotions while others like Kant have held that it originated from rational and logical thought. 20th-century philosophers such as Wittgenstein argued that philosophy is really the study of language. Major fgures in linguistics include Ferdinand de Saussure and Noam Chomsky. Estimates of the number of human languages in the world vary between 5,000 and 7,000. However, any precise estimate depends on the arbitrary distinction (dichotomy) between languages and dialect.[4] Natural languages are spoken or signed, but any language can be encoded into secondary media using auditory, visual, or tactile stimuli – for example, in writing, whistling, signing, or braille. Tis is because human language is modality-independent. Depending on philosophical perspectives regarding the defnition of language and meaning, when used as a general concept, "language" may refer to the cognitive ability to learn and use systems of complex communication, or to describe the set of rules that makes up these systems, or the set of utterances that can be produced from those rules. All languages rely on the process of semiosis to relate signs to particular meanings. Oral, manual and tactile languages contain a phonological system that governs how symbols are used to form sequences known as words or morphemes, and a syntactic system that governs how words and morphemes are combined to form phrases and utterances. Human language has the properties of productivity and displacement, and relies entirely on social convention and learning. Its complex structure aﬀords a much wider range of expressions than any known system of animal communication. Language is thought to have originated when early hominins started gradually changing their primate communication systems, acquiring the ability to form a theory of other minds and a shared intentionality.[5][6] Tis development is sometimes thought to have coincided with an increase in brain volume, and many linguists see the structures of language as having evolved to serve specifc communicative and social functions. Language is processed in many diﬀerent locations in the human brain, but especially in Broca's and Wernicke's areas. Humans acquire language through social interaction in early childhood, and children generally speak fuently by approximately three years old. Te use of language is deeply entrenched in human culture. Terefore, in addition to its strictly communicative uses, language also has many social and cultural uses, such as signifying group identity, social stratifcation, as well as social grooming and entertainment. Languages evolve and diversify over time, and the history of their evolution can be reconstructed by comparing modern languages to determine which traits their ancestral languages must have had in order for the later developmental stages to occur. A group of languages that descend from a common ancestor is known as a language family. Te Indo-European family is the most widely spoken and includes languages as diverse as English, Russian and Hindi; the Sino-Tibetan family includes Mandarin and the other Chinese languages, Bodo and Tibetan; the Afro-Asiatic family includes Arabic, Somali, and Hebrew; the Bantu languages include Swahili, and Zulu, and hundreds of other languages spoken throughout Africa; and the Malayo-Polynesian languages include Indonesian, Malay, Tagalog, and hundreds of other languages spoken throughout the Pacifc. Te languages of the Dravidian family, spoken mostly in Southern India, include Tamil, Telugu and Kannada. Academic consensus holds that between 50% and 90% of languages spoken at the beginning of the 21st century will probably have become extinct by the year 2100.

Linguistics is the scientifc study of language.[1] It involves analysing language form, language meaning, and language in context.[2] Linguists traditionally analyse human language by observing an interplay between sound and meaning. [3] Linguistics also deals with the social, cultural, historical and political factors that infuence language, through which linguistic and language-based context is often determined.[4] Research on language through the sub-branches of historical and evolutionary linguistics also focuses on how languages change and grow, particularly over an extended period of time. 266 Te earliest activities in the documentation and description of language have been attributed to the 6th-century- BC Indian grammarian Pāṇini[5][6] who wrote a formal description of the Sanskrit language in his Aṣṭādhyāyī.[7] Related areas of study include the disciplines of semiotics (the study of direct and indirect language through signs and symbols), literary criticism (the historical and ideological analysis of literature, cinema, art, or published material), translation (the conversion and documentation of meaning in written/spoken text from one language or dialect onto another), and speech-language pathology (a corrective method to cure phonetic disabilities and dis-functions at the cognitive level).

Communication (from Latin communicare, meaning "to share")[1] is the act of conveying meanings from one entity or group to another through the use of mutually understood signs, symbols, and semiotic rules. Te main steps inherent to all communication are:[2] 1. Te formation of communicative motivation or reason. 2. Message composition (further internal or technical elaboration on what exactly to express). 3. Message encoding (for example, into digital data, written text, speech, pictures, gestures and so on). 4. Transmission of the encoded message as a sequence of signals using a specifc channel or medium. 5. Noise sources such as natural forces and in some cases human activity (both intentional and accidental) begin infuencing the quality of signals propagating from the sender to one or more receivers. 6. Reception of signals and reassembling of the encoded message from a sequence of received signals. 7. Decoding of the reassembled encoded message. 8. Interpretation and making sense of the presumed original message. Te scientifc study of communication can be divided into:

• Information theory which studies the quantifcation, storage, and communication of information in general; • Communication studies which concerns human communication; • Biosemiotics which examines communication in and between living organisms in general. Te channel of communication can be visual, auditory, tactile/haptic (e.g. Braille or other physical means), olfactory, electromagnetic, or biochemical. Human communication is unique for its extensive use of abstract language. Development of civilization has been closely linked with progress in telecommunication.

Universal language may refer to a hypothetical or historical language spoken and understood by all or most of the world's population. In some contexts, it refers to a means of communication said to be understood by all living things, beings, and objects alike. It may be the idea of an international auxiliary language for communication between groups speaking diﬀerent primary languages. In other conceptions, it may be the primary language of all speakers, or the only existing language. Some religious and mythological traditions state that there was once a single universal language among all people, or shared by humans and supernatural beings.

In other traditions, there is less interest in or a general defection of the question. For example in Islam the Arabic language is the language of the Qur'an, and so universal for Muslims. Te written Classical Chinese language was and is still read widely but pronounced diﬀerently by readers in China, Vietnam, Korea and Japan; for centuries it was a de facto universal literary language for a broad-based culture. In something of the same way Sanskrit in India and Nepal, Tamil in India and Sri Lanka and Pali in Sri Lanka and in Teravada countries of South-East Asia (Burma, Tailand, Cambodia), were literary languages for many for whom they were not their mother tongue.

Comparably, the Latin language (qua Medieval Latin) was in eﬀect a universal language of literati in the Middle Ages, and the language of the Vulgate Bible in the area of Catholicism, which covered most of Western Europe and parts of Northern and Central Europe also.

In a more practical fashion, trade languages, such as ancient Koine Greek, may be seen as a kind of real universal language, that was used for commerce.

In historical linguistics, monogenesis refers to the idea that all spoken human languages are descended from a single ancestral language spoken many thousands of years ago.

267 Te Ethnologue catalogue of world languages, which is one of the best linguistic resources, currently lists 6909 living languages. About 6% of them have more than a million speakers each, and collectively account for 94% of the world population. All languages have fathers and mothers, all built from animism, phonetics, semantic teachers and philologists and etymologists , tho everyone has they’re own language deep benith.

Linguistics is the scientifc study of language, and involves an analysis of language form, language meaning, and language in context.

Linguists traditionally analyse human language by observing an interplay between sound and meaning. Phonetics is the study of speech and non-speech sounds, and delves into their acoustic and articulatory properties. Te study of language meaning, on the other hand, deals with how languages encode relations between entities, properties, and other aspects of the world to convey, process, and assign meaning, as well as manage and resolve ambiguity. While the study of semantics typically concerns itself with truth conditions, pragmatics deals with how situational context infuences the production of meaning.

Discourse (from Latin discursus, "running to and from") denotes written and spoken communications.

In semantics and discourse analysis: Discourse is a conceptual generalization of conversation within each modality and context of communication. Te totality of codifed language (vocabulary) used in a given feld of intellectual enquiry and of social practice, such as the dance of the phonemes and song of the vowels. In the work of Michel Foucault, and that of the social theoreticians he inspired: discourse describes "an entity of sequences, of signs, in that they are enouncements (énoncés)", statements in conversation.

As discourse, an enouncement (statement) is not a unit of semiotic signs, but an abstract construct that allows the semiotic signs to assign meaning, and so communicate specifc, repeatable communications to, between, and among objects, subjects, and statements. Terefore, a discourse is composed of semiotic sequences (relations among signs that communicate meaning) between and among objects, subjects, and statements.

Te term "discursive formation" (French: formation discursive) conceptually describes the regular communications (written and spoken) that produce such discourses, such as informal conversations. As a philosopher, Michel Foucault applied the discursive formation in the analyses of large bodies of knowledge, such as political economy and natural history.

In the frst sense-usage (semantics and discourse analysis), the term discourse is studied in corpus linguistics, the study of language expressed in corpora (samples) of "real world" text. In the second sense (the codifed language of a feld of enquiry) and in the third sense (a statement, un énoncé), the analysis of a discourse examines and determines the connections among language and structure and agency.

Moreover, because a discourse is a body of text meant to communicate specifc data, information, and knowledge, there exist internal relations in the content of a given discourse; likewise, there exist external relations among discourses. As such, a discourse does not exist per se (in itself), but is related to other discourses, by way of inter-discursivity; therefore, in the course of intellectual enquiry, the discourse among researchers features the questions and answers of What is ...? and What is not. ..., conducted according to the meanings (denotation and connotation) of the concepts (statements) used in the given feld of enquiry, such as anthropology, ethnography, and sociology; cultural studies and literary theory; the philosophy of science and feminism.

Grammar is a system of rules which governs the production and use of utterances in a given language. Tese rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Modern theories that deal with the principles of grammar are largely based within Noam Chomsky's framework of generative linguistics.

In the early 20th century, Ferdinand de Saussure distinguished between the notions of langue and parole in his formulation of structural linguistics. According to him, parole is the specifc utterance of speech, whereas langue refers to an abstract phenomenon that theoretically defnes the principles and system of rules that govern a language. Tis distinction resembles the one made by Noam Chomsky between competence and performance in his theory of transformative or generative grammar. According to Chomsky, competence is an individual's innate capacity and potential for language (like in Saussure's langue), while performance is the specifc way in which it is used by individuals, groups, and communities (i.e., parole, in Saussurean terms).

268 Te study of parole (which manifests through cultural discourses and dialects) is the domain of sociolinguistics, the sub- discipline that comprises the study of a complex system of linguistic facets within a certain speech community (governed by its own set of grammatical rules and laws). Discourse analysis further examines the structure of texts and conversations emerging out of a speech community's usage of language. Tis is done through the collection of linguistic data, or through the formal discipline of corpus linguistics, which takes naturally occurring texts and studies the variation of grammatical and other features based on such corpora (or corpus data).

Stylistics also involves the study of written, signed, or spoken discourse through varying speech communities, genres, and editorial or narrative formats in the mass media. In the 1960s, Jacques Derrida, for instance, further distinguished between speech and writing, by proposing that written language be studied as a linguistic medium of communication in itself. Palaeography is therefore the discipline that studies the evolution of written scripts (as signs and symbols) in language. Te formal study of language also led to the growth of felds like psycholinguistics, which explores the representation and function of language in the mind; neurolinguistics, which studies language processing in the brain; biolinguistics, which studies the biology and evolution of language; and language acquisition, which investigates how children and adults acquire the knowledge of one or more languages.

Linguistics also deals with the social, cultural, historical and political factors that infuence language, through which linguistic and language-based context is often determined. Research on language through the sub-branches of historical and evolutionary linguistics also focus on how languages change and grow, particularly over an extended period of time.

Language documentation combines anthropological inquiry (into the history and culture of language) with linguistic inquiry, in order to describe languages and their grammars. Lexicography involves the documentation of words that form a vocabulary. Such a documentation of a linguistic vocabulary from a particular language is usually compiled in a dictionary. Computational linguistics is concerned with the statistical or rule-based modeling of natural language from a computational perspective. Specifc knowledge of language is applied by speakers during the act of translation and interpretation, as well as in language education – the teaching of a second or foreign language. Policy makers work with governments to implement new plans in education and teaching which are based on linguistic research.

Related areas of study also includes the disciplines of semiotics (the study of direct and indirect language through signs and symbols), literary criticism (the historical and ideological analysis of literature, cinema, art, or published material), translation (the conversion and documentation of meaning in written/spoken text from one language or dialect onto another), and speech-language pathology (a corrective method to cure phonetic disabilities and dis-functions at the cognitive level).

Philology is the study of language in oral and written historical sources; it is a combination of literary criticism, history, and linguistics. It is more commonly defned as the study of literary texts pas well as oral and written records, the establishment of their authenticity and their original form, and the determination of their meaning. A person who pursues this kind of study is known as a philologist.

In older usage, especially British, philology is more general, covering comparative and historical linguistics.

Classical philology studies classical languages. Classical philology principally originated from the Library of Pergamum and the Library of Alexandria around the fourth century BCE, continued by Greeks and Romans throughout the Roman/ Byzantine Empire, preserved and promoted during the Islamic Golden Age, and eventually resumed by European scholars of the Renaissance, where it was soon joined by philologies of other non-Asian (European) (Germanic, Celtic), Eurasian (Slavistics, etc.) and Asian (Sanskrit, Persian, Arabic, Chinese, etc.) languages. Indo-European studies involves the comparative philology of all Indo-European languages.

Te word grammar is derived from Greek γραμματικὴ τέχνη (grammatikē technē), which means "art of letters", from γράμμα (gramma), "letter", itself from γράφειν (graphein), "to draw, to write”. Te same Greek root also appears in graphics, grapheme, and photograph. In linguistics, grammar (from Greek: γραμματική) is the set of structural rules governing the composition of clauses, phrases, and words in any given natural language. Te term refers also to the study of such rules, and this feld includes phonology, morphology, and syntax, often complemented by phonetics, semantics, and pragmatics.

Punctuation (formerly sometimes called pointing) is the use of spacing, conventional signs and certain typographical devices as aids to the understanding and correct reading of handwritten and printed text whether read silently or aloud. Another description is, "It is the practice action or system of inserting points or other small marks into texts in order to aid interpretation; division of text into sentences, clauses, etc., by means of such marks." 269 In written Banoshie, punctuation is vital to disambiguate the meaning of sentences. For example: "woman, without her man, is nothing" (emphasizing the importance of men), and "woman: without her, man is nothing" (emphasizing the importance of women) have very different meanings; as do "eats shoots and leaves" (which means the subject consumes plant growths) and "eats, shoots, and leaves" (which means the subject eats frst, then fres a weapon, and then leaves the scene). Te sharp differences in meaning are produced by the simple differences in punctuation within the example pairs, especially the latter.

Asemic writing is a wordless open semantic form of writing.[1][2][3] Te word asemic means "having no specifc semantic content", or "without the smallest unit of meaning".[4] With the non-specifcity of asemic writing there comes a vacuum of meaning, which is left for the reader to fll in and interpret. All of this is similar to the way one would deduce meaning from an abstract work of art. Where asemic writing diﬀers from abstract art is in the asemic author's use of gestural constraint, and the retention of physical characteristics of writing such as lines and symbols. Asemic writing is a hybrid art form that fuses text and image into a unity, and then sets it free to arbitrary subjective interpretations. It may be compared to free writing or writing for its own sake, instead of writing to produce verbal context. Te open nature of asemic works allows for meaning to occur across linguistic understanding; an asemic text may be "read" in a similar fashion regardless of the reader's natural language.[5] Multiple meanings for the same symbolism are another possibility for an asemic work, that is, asemic writing can be polysemantic or have zero meaning, infnite meanings, or its meaning can evolve over time.[6] Asemic works leave for the reader to decide how to translate and explore an asemic text; in this sense, the reader becomes co-creator of the asemic work.

In 1997 visual poets Tim Gaze and Jim Leftwich frst applied the word asemic to name their quasi-calligraphic writing gestures.[7] Tey then began to distribute them to poetry magazines both online and in print. Te authors explored sub- verbal and sub-letteral forms of writing, and textual asemia as a creative option and as an intentional practice. Since the late 1990s, asemic writing has blossomed into a worldwide literary/art movement. It has especially grown in the early part of the 21st century, though there is an acknowledgement of a long and complex history, which precedes the activities of the current asemic movement, especially with regards to abstract calligraphy, wordless writing, and verbal writing damaged beyond the point of legibility. Jim Leftwich has recently stated that an asemic condition of an asemic work is an impossible goal, and that it is not possible to create an art/literary work entirely without meaning. He has begun to use the term "pansemic" to describe this type of work.[8] Others such as author Travis Jeppesen have found the term asemic to be problematic because "it seems to infer writing with no meaning.

Graphology (or graphoanalysis, but not graphanalysis) is the analysis of the physical characteristics and patterns of handwriting claiming to be able to identify the writer, indicating psychological state at the time of writing, or evaluating personality characteristics. It is generally considered a pseudoscience. Te term is sometimes incorrectly used to refer to forensic document examination, due to the fact that aspects of the latter dealing with the examination of handwritten documents are occasionally referred to as graphanalysis.

Graphology has been controversial for more than a century. Although supporters point to the anecdotal evidence of positive testimonials as a reason to use it for personality evaluation, empirical studies fail to show the validity claimed by its supporters.

Signs with two diﬀerent expressions. Te pursed lips and partly closed eyes on the left, and raised lip on the right, are necessary for proper formation of the signs. In sign languages, expressions are the distinctive body postures and facial expressions that accompany signing, and which are necessary to properly form words. Expression is one of fve components of a sign, along with handshape (dez), orientation (ori), location (tab), and movement (sig). A major component of expression is mouthing. However, not all signs have an inherent expression.

A symbol is a mark, sign or word that indicates, signifes, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very diﬀerent concepts and experiences. All communication (and data processing) is achieved through the use of symbols. Symbols take the form of words, sounds, gestures, ideas or visual images and are used to convey other ideas and beliefs. For example, a red octagon may be a symbol for "STOP". On a map, a blue line might represent a river. Numerals are symbols for numbers. Alphabetic letters may be symbols for sounds. Personal names are symbols representing individuals. A red rose may symbolize love and compassion. Te variable 'x', in a mathematical equation, may symbolize the position of a particle in space.

Pronunciation

Pronunciation is the way in which a word or a language is spoken. Tis may refer to generally agreed-upon sequences of sounds used in speaking a given word or language in a specifc dialect ("correct pronunciation"), or simply the way a particular individual speaks a word or language.

270 A word can be spoken in diﬀerent ways by various individuals or groups, depending on many factors, such as: the duration of the cultural exposure of their childhood, the location of their current residence, speech or voice disorders,[1] their ethnic group, their social class, or their education.[2] enPR: -ĭshən, IPA(key): /-ɪʃən/ A synonym is a word or phrase that means exactly or nearly the same as another lexeme in the same language. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. For example, the words begin, start, commence, and initiate are all synonyms of one another.

In etymology, back-formation is the process of creating a new lexeme by removing actual or supposed aﬃxes. Te resulting neologism is called a back-formation, a term coined by James Murray in 1889. (OED online preserves their frst use of 'back formation' from 1889 in the defnition of to burgle.)

For example, the noun resurrection was borrowed from Latin, and the verb resurrect was then backformed hundreds of years later from it by removing the ion suﬃx. Tis segmentation of resurrection into resurrect + ion was possible because English had examples of Latinate words in the form of verb and verb+-ion pairs, such as opine/opinion. Tese became the pattern for many more such pairs, where a verb derived from a Latin supine stem and a noun ending in ion entered the language together, such as insert/insertion, project/projection, etc.

In development or moral, political, and bioethical philosophy, autonomy is the capacity to make an informed, un-coerced decision, this depends on understanding of language, law and justice to every degree. Autonomous organizations or institutions are independent or self-governing. Autonomy can also be defned from human resource perspective and it means a level of discretion granted to an employee in his or her work. In such cases, autonomy is known to bring some sense of job satisfaction among the employees. Autonomy is a term that is also widely used and in the feld of medicine. As a matter of fact, personal autonomy is greatly recognized and valued in health care.

Te rules of punctuation vary with language, location, register and time and are constantly evolving. Certain aspects of punctuation are stylistic and are thus the author's (or editor's) choice, or tachygraphic language forms, such as those used in online chat and text messages.

Phonology is a branch of linguistics concerned with the systematic organization of sounds in languages. It has traditionally focused largely on the study of the systems of phonemes in particular languages (and therefore used to be also called phonemics, or phonematics), but it may also cover any linguistic analysis either at a level beneath the word (including syllable, onset and rime, articulatory gestures, articulatory features, mora, etc.) or at all levels of language where sound is considered to be structured for conveying linguistic meaning.

Phonology also includes the study of equivalent non-oral languages such as ASL or other sign

In linguistics, morphology (/mɔːrˈfɒlədʒi/) is the study of words, how they are formed, and their relationship to other words in the same language. It analyzes the structure of words and parts of words, such as stems, root words, prefxes, and suﬃxes. Morphology also looks at parts of speech, intonation and stress, and the ways context can change a word's pronunciation and meaning. Morphology diﬀers from morphological typology, which is the classifcation of languages based on their use of words,[4] and lexicology, which is the study of words and how they make up a language's vocabulary.[5]

In linguistics, syntax (/ˈsɪntæks/[) is the set of rules, principles, and processes that govern the structure of sentences in a given language, specifcally word order and punctuation. Te term syntax is also used to refer to the study of such principles and processes. Te goal of many syntacticians is to discover the syntactic rules common to all languages.

In mathematics, syntax refers to the rules governing the behavior of mathematical systems, such as formal languages used in logic.

Phonetics (pronounced /fəˈnɛtɪks/) is a branch of linguistics that studies the sounds of human speech, or—in the case of sign languages—the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs (phones): their physiological production, acoustic properties, auditory perception, and neurophysiological status. Phonology, on the other hand, is concerned with the abstract, grammatical characterization of systems of sounds or signs.

271 A phoneme (/ˈfoʊniːm/) is one of the units of sound (or gesture in the case of sign languages, see chereme) that distinguish one word from another in a particular language. For example, in most dialects of English, the sound patterns /θʌm/ (thumb) and /dʌm/ (dumb) are two separate words distinguished by the substitution of one phoneme, /θ/, for another phoneme, /d/. (Two words like this that diﬀer in meaning through a contrast of a single phoneme form what is called a minimal pair). In many other languages these would be interpreted as exactly the same set of phonemes (i.e. /θ/ and /d/ would be considered the same).

In linguistics, phonemes (usually established by the use of minimal pairs, such as kill vs kiss or pat vs bat) are written between slashes, e.g. /p/. To show pronunciation more precisely linguists use square brackets, for example [ph] (indicating an aspirated p).

Within linguistics there are diﬀering views as to exactly what phonemes are and how a given language should be analyzed in phonemic (or phonematic) terms. However, a phoneme is generally regarded as an abstraction of a set (or equivalence class) of speech sounds (phones) which are perceived as equivalent to each other in a given language. For example, in English, the k sounds in the words kit and skill are not identical (as described below), but they are distributional variants of a single phoneme /k/. Diﬀerent speech sounds that are realizations of the same phoneme are known as allophones. Allophonic variation may be conditioned, in which case a certain phoneme is realized as a certain allophone in particular phonological environments, or it may be free in which case it may vary randomly. In this way, phonemes are often considered to constitute an abstract underlying representation for segments of words, while speech sounds make up the corresponding phonetic realization, or surface form.

In the case of oral languages, phonetics has three basic areas of study:

Articulatory phonetics: the study of the organs of speech and their use in producing speech sounds by the speaker. Acoustic phonetics: the study of the physical transmission of speech sounds from the speaker to the listener. Auditory phonetics: the study of the reception and perception of speech sounds by the listener.

Semantics (from Ancient Greek: σημαντικός sēmantikos, "signifcant") is the linguistic and philosophical study of meaning, in language, programming languages, formal logics, and semiotics. It is concerned with the relationship between signifers—like words, phrases, signs, and symbols—and what they stand for, their denotation.

Pragmatics is a subfeld of linguistics and semiotics that studies the ways in which context contributes to meaning. Pragmatics encompasses speech act theory, conversational implicature, talk in interaction and other approaches to language behavior in philosophy, sociology, linguistics and anthropology. Unlike semantics, which examines meaning that is conventional or "coded" in a given language, pragmatics studies how the transmission of meaning depends not only on structural and linguistic knowledge (e.g., grammar, lexicon, etc.) of the speaker and listener, but also on the context of the utterance, any pre-existing knowledge about those involved, the inferred intent of the speaker, and other factors. In this respect, pragmatics explains how language users are able to overcome apparent ambiguity, since meaning relies on the manner, place, time etc. of an utterance.

Te ability to understand another speaker's intended meaning is called pragmatic competence.

A metaphor is a fgure of speech that directly refers to one thing by mentioning another for rhetorical eﬀect. It may provide clarity or identify hidden similarities between two ideas. Antithesis, hyperbole, metonymy and simile are all types of metaphor. One of the most commonly cited examples of a metaphor in English literature is the "All the world's a stage" monologue from As You Like It:

All the world's a stage, And all the men and women merely players; Tey have their exits and their entrances ... —William Shakespeare, As You Like It.

Tis quotation expresses a metaphor because the world is not literally a stage. By asserting that the world is a stage, Shakespeare uses points of comparison between the world and a stage to convey an understanding about the mechanics of the world and the behavior of the people within it.

Te Philosophy of Rhetoric (1937) by rhetorician I. A. Richards describes a metaphor as having two parts: the tenor and the vehicle. Te tenor is the subject to which attributes are ascribed. Te vehicle is the object whose attributes are borrowed. In the previous example, "the world" is compared to a stage, describing it with the attributes of "the stage"; "the world" is the tenor, and "a stage" is the vehicle; "men and women" is the secondary tenor, and "players" is the secondary vehicle. 272 Other writers employ the general terms ground and fgure to denote the tenor and the vehicle. Cognitive linguistics uses the terms target and source, respectively.

In linguistics, word formation is the creation of a new word. Word formation is sometimes contrasted with semantic change, which is a change in a single word's meaning. Te boundary between word formation and semantic change can be diﬃcult to defne: a new use of an old word can be seen as a new word derived from an old one and identical to it in form. See 'conversion'.

Communication (from Latin commūnicāre, meaning "to share") is the act of conveying intended meanings from one entity or group to another through the use of mutually understood signs and semiotic rules.

Telepathy (from the Greek τῆλε, tele meaning "distant" and πάθος, pathos or -patheia meaning "feeling, perception, passion, aﬄiction, experience")is the purported transmission of information from one person to another without using any of our known sensory channels or physical interaction. Te term was coined in 1882 by the classical scholar Frederic W. H. Myers, a founder of the Society for Psychical Research, and has remained more popular than the earlier expression thought- transference.

Ethnolinguistics (sometimes called cultural linguistics)[1] is a feld of linguistics which studies the relationship between language and culture, and the way diﬀerent ethnic groups perceive the world. It is the combination between ethnology and linguistics. Te former refers to the way of life of an entire community, i.e., all the characteristics which distinguish one community from the other. Tose characteristics make the cultural aspects of a community or a society.

Ethnolinguists study the way perception and conceptualization infuences language, and show how this is linked to diﬀerent cultures and societies. An example is the way spatial orientation is expressed in various cultures.[2][3] In many societies, words for the cardinal directions east and west are derived from terms for sunrise/sunset. Te nomenclature for cardinal directions of Inuit speakers of Greenland, however, is based on geographical landmarks such as the river system and one's position on the coast. Similarly, the Yurok lack the idea of cardinal directions; they orient themselves with respect to their principal geographic feature, the Klamath River.

Cultural linguistics is a related branch of linguistics that explores the relationship between language and cultural conceptualisations (Sharifan, 2011). Cultural Linguistics draws on and expands the theoretical and analytical advancements in cognitive science (including complexity science and distributed cognition) and anthropology. Cultural Linguistics examines how various features of human languages encode cultural conceptualisations, including cultural schemas, cultural categories, and cultural metaphors.[4] In Cultural Linguistics, language is viewed as deeply entrenched in the group-level, cultural cognition of communities of speakers. Tus far, the approach of Cultural Linguistics has been adopted in several areas of applied linguistic research, including intercultural communication, second language learning, and World languages

Phonaesthetics (from the Greek: φωνή phōnē, "voice-sound"; and αἰσθητική aisthētikē, "aesthetics") is a branch of phonetics concerned with "the possible connection between sound sequences and meaning", according to Raymond Hickey. Linguist David Crystal defnes phonaesthetics as "a term sometimes used in linguistics to refer to the study of the aesthetic properties of sound".Euphony is used for effects which are pleasant, rhythmical and harmonious Cacophony consists of harsh, often discordant sounds. Tese sounds are often meaningless and jumbled together. A discordant series of harsh, unpleasant sounds helps to convey disorder. Tis is often furthered by the combined effect of the meaning and the difficulty of pronunciation.

In linguistics, sound symbolism, phonesthesia or phonosemantics is the idea that vocal sounds or phonemes carry meaning in and of themselves.

Tis is the least signifcant type of symbolism. It is simply imitative of sounds or suggests something that makes a sound. Some examples are crash, bang, whoosh.

Words that share a sound sometimes have something in common. If we take, for example, words that have no prefx or suﬃx and group them according to meaning, some of them will fall into a number of categories. So we fnd that there is a group of words beginning with /b/ that are about barriers, bulges and bursting, and some other group of /b/ words that are about being banged, beaten, battered, bruised, blistered and bashed. Tis proportion is, according to Magnus, above the average for other letters.

Another hypothesis states that if a word begins with a particular phoneme, then there is likely to be a number of other words starting with that phoneme that refer to the same thing. An example given by Magnus is if the basic word for 'house' in a

273 given language starts with a /h/, then by clustering, disproportionately many words containing /h/ can be expected to concern housing: hut, home, hovel, habitat...

Clustering is language dependent, although closely related languages will have similar clustering relationships.

Iconism, according to Magnus, becomes apparent when comparing words which have the same sort of referent. One way is to look at a group of words that all refer to the same thing and that diﬀer only in their sound, such as 'stamp', 'stomp', 'tamp', 'tromp', 'tramp', and 'step'. An /m/ before the /p/ in some words makes the action more forceful; compare 'stamp' with 'step' or 'tamp' with 'tap'. According to Magnus, the /r/ sets the word in motion, especially after a /t/ so a 'tamp' is in one place, but a 'tramp' goes for a walk. Te /p/ in all those words would be what emphasizes the individual steps.

Magnus suggests that this kind of iconism is universal across languages. Some languages possess a category of words midway between onomatopoeia and usual words. Whereas onomatopoeia refers to the use of words to imitate actual sounds, there are languages known for having a special class of words that "imitate" soundless states or events, called phenomimes (when they describe external phenomena) and psychomimes (when they describe psychological states). On a scale that orders all words according to the correlation between their meaning and their sound, with the sound-imitating words like meow and whack at one end, and with the conventional words like water and blue at the other end, the phenomimes and the psychomimes would be somewhere in the middle. In the case of the Japanese language, for example, such words are learned in early childhood and are considerably more eﬀective than usual words in conveying feelings and states of mind or in describing states, motions, and transformations.[2] Tey are not found, however, only in children's vocabulary, but widely used in daily conversation among adults and even in more formal writing. Like Japanese, the Korean language also has a relatively high proportion of phenomimes and psychomimes.

In poetry, metre is the basic rhythmic structure of a verse or lines in verse. Many traditional verse forms prescribe a specifc verse metre, or a certain set of metres alternating in a particular order. Te study and the actual use of metres and forms of versifcation are both known as prosody. (Within linguistics, "prosody" is used in a more general sense that includes not only poetic metre but also the rhythmic aspects of prose, whether formal or informal, that vary from language to language, and sometimes between poetic traditions.)

In linguistics, prosody is concerned with those elements of speech that are not individual phonetic segments (vowels and consonants) but are properties of syllables and larger units of speech. Tese contribute to linguistic functions such as intonation, tone, stress, and rhythm. Prosody may refect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance (statement, question, or command); the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of language that may not be encoded by grammar or by choice of vocabulary.

Prose is a form of language that exhibits a natural fow of speech and grammatical structure rather than a rhythmic structure as in traditional poetry, where the common unit of verse is based on meter or rhyme.

A rhyme is a repetition of similar sounds (or the same sound) in two or more words, most often in the fnal syllables of lines in poems and songs. Te word rhyme is also a pars pro toto ("a part (taken) for the whole") that means a short poem, such as a rhyming couplet or other brief rhyming poem such as nursery rhymes.

Te formation of communicative motivation or reason. Message composition (further internal or technical elaboration on what exactly to express). Message encoding (for example, into digital data, written text, speech, pictures, gestures and so on). Transmission of the encoded message as a sequence of signals using a specifc channel or medium. Noise sources such as natural forces and in some cases human activity (both intentional and accidental) begin infuencing the quality of signals propagating from the sender to one or more receivers. Reception of signals and reassembling of the encoded message from a sequence of received signals. Decoding of the reassembled encoded message. Interpretation and making sense of the presumed original message. Te scientifc study of communication can be divided into:

Information theory which studies the quantifcation, storage, and communication of information in general; Communication studies which concerns human communication; Biosemiotics which examines communication in and between living organisms in general. Te channel of communication can be visual, auditory, tactile (such as in Braille) and haptic, olfactory, electromagnetic, or biochemical.

Human communication is unique for its extensive use of abstract language. Development of civilization has been closely linked with progress in telecommunication.

A symbol is a mark, sign, or word that indicates, signifes, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very diﬀerent concepts

274 and experiences. All communication (and data processing) is achieved through the use of symbols. Symbols take the form of words, sounds, gestures, ideas or visual images and are used to convey other ideas and beliefs. For example, a red octagon may be a symbol for "STOP". On a map, a blue line might represent a river. Numerals are symbols for numbers. Alphabetic letters may be symbols for sounds. Personal names are symbols representing individuals. A red rose may symbolize love and compassion. Te variable 'x', in a mathematical equation, may symbolize the position of a particle in space.In cartography, an organized collection of symbols forms a legend for a map.

A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or medical symptoms signify a disease. A conventional sign signifes by agreement, as a full stop signifes the end of a sentence; similarly the words and expressions of a language, as well as bodily gestures, can be regarded as signs, expressing particular meanings. Te physical objects most commonly referred to as signs (notices, road signs, etc., collectively known as signage) generally inform or instruct using written text, symbols, pictures or a combination of these.

Semiotics, epistemology, logic, and philosophy of language are concerned about the nature of signs, what they are and how they signify. Te nature of signs and symbols and signifcations, their defnition, elements, and types, is mainly established by Aristotle, Augustine, and Aquinas. According to these classic sources, signifcance is a relationship between two sorts of things: signs and the kinds of things they signify (intend, express or mean), where one term necessarily causes something else to come to the mind. Distinguishing natural signs and conventional signs, the traditional theory of signs (Augustine) sets the following threefold partition of things: all sorts of indications, evidences, symptoms, and physical signals, there are signs which are always signs (the entities of the mind as ideas and images, thoughts and feelings, constructs and intentions); and there are signs that have to get their signifcation (as linguistic entities and cultural symbols). So, while natural signs serve as the source of signifcation, the human mind is the agency through which signs signify naturally occurring things, such as objects, states, qualities, quantities, events, processes, or relationships. Human language and discourse, communication, philosophy, science, logic, mathematics, poetry, theology, and religion are only some of felds of human study and activity where grasping the nature of signs and symbols and patterns of signifcation may have a decisive value.

Te philosophical study of signs and symbols is called semiotics; this includes the study of semiosis, which is the way in which signs (in the semiotic sense) operate.

Semiotics (also called semiotic studies) is the study of meaning-making, the study of sign process (semiosis) and meaningful communication. It is not to be confused with the Saussurean tradition called semiology which is a subset of semiotics. Tis includes the study of signs and sign processes, indication, designation, likeness, analogy, allegory, metonymy, metaphor, symbolism, signifcation, and communication.

Te semiotic tradition explores the study of signs and symbols as a signifcant part of communications. As diﬀerent from linguistics, however, semiotics also studies non-linguistic sign systems.

Semiotics is frequently seen as having important anthropological dimensions; for example, the Italian semiotician and novelist Umberto Eco proposed that every cultural phenomenon may be studied as communication. Some semioticians focus on the logical dimensions of the science, however. Tey examine areas belonging also to the life sciences—such as how organisms make predictions about, and adapt to, their semiotic niche in the world (see semiosis). In general, semiotic theories take signs or sign systems as their object of study: the communication of information in living organisms is covered in biosemiotics (including zoosemiotics).

Punctuation (formerly sometimes called pointing) is the use of spacing, conventional signs, and certain typographical devices as aids to the understanding and the correct reading, both silently and aloud, of handwritten and printed texts. Another description is: "Te practice, action, or system of inserting points or other small marks into texts, in order to aid interpretation; division of text into sentences, clauses, etc., by means of such marks."

In written English, punctuation is vital to disambiguate the meaning of sentences. For example: "woman, without her man, is nothing" (emphasizing the importance of men), and "woman: without her, man is nothing" (emphasizing the importance of women) have very different meanings; as do "eats shoots and leaves" (which means the subject consumes plant growths) and "eats, shoots, and leaves" (which means the subject eats frst, then fres a weapon, and then leaves the scene). Te sharp differences in meaning are produced by the simple differences in punctuation within the example pairs, especially the latter.

275 A lexicon, word-hoard, wordbook, or word-stock is the vocabulary of a person, language, or branch of knowledge (such as nautical or medical). In linguistics, a lexicon is a language's inventory of lexemes. Te word "lexicon" derives from the Greek λεξικόν (lexicon), neuter of λεξικός (lexikos) meaning "of or for words."[1] Linguistic theories generally regard human languages as consisting of two parts: a lexicon, essentially a catalogue of a language's words (its wordstock); and a grammar, a system of rules which allow for the combination of those words into meaningful sentences. Te lexicon is also thought to include bound morphemes, which cannot stand alone as words (such as most aﬃxes).[2] In some analyses, compound words and certain classes of idiomatic expressions and other collocations are also considered to be part of the lexicon. Dictionaries represent attempts at listing, in alphabetical order, the lexicon of a given language; usually, however, bound morphemes are not included.

In linguistics, grammar (from Ancient Greek γραμματική) is the set of structural rules governing the composition of clauses, phrases and words in a natural language. Te term refers also to the study of such rules and this feld includes phonology, morphology and syntax, often complemented by phonetics, semantics and pragmatics. Fluent speakers of a language variety or lect have a set of internalized rules which constitutes its grammar.[1] Te vast majority of the information in the grammar is – at least in the case of one's native language – acquired not by conscious study or instruction but by hearing other speakers. Much of this work is done during early childhood; learning a language later in life usually involves more explicit instruction.[2] Tus, grammar is the cognitive information underlying language use. Te term "grammar" can also describe the rules which govern the linguistic behavior of a group of speakers. For example, the term "English grammar" may refer to the whole of English grammar; that is, to the grammars of all the speakers of the language, in which case the term encompasses a great deal of variation.[3] Alternatively, it may refer only to what is common to the grammars of all or most English speakers (such as subject–verb–object word order in simple declarative sentences). It may also refer to the rules of one relatively well-defned form of English (such as standard English for a region). A description, study, or analysis of such rules may also be referred to as a grammar. A reference book describing the grammar of a language is called a "reference grammar" or simply "a grammar" (see History of English grammars). A fully explicit grammar which exhaustively describes the grammatical constructions of a particular speech variety is called a descriptive grammar. Tis kind of linguistic description contrasts with linguistic prescription, an attempt to actively discourage or suppress some grammatical constructions, while codifying and promoting others, either in an absolute sense or in reference to a standard variety. For example, some prescriptivists maintain that sentences in English should not end with prepositions, a prohibition that has been traced to John Dryden (13 April 1668 – January 1688) whose unexplained objection to the practice perhaps led other English speakers to avoid the construction and discourage its use.[4][5] Yet preposition stranding has a long history in Germanic languages like English, where it is so widespread as to be a standard usage. Outside linguistics, the term grammar is often used in a rather diﬀerent sense. It may be used more broadly to include conventions of spelling and punctuation, which linguists would not typically consider as part of grammar but rather as part of orthography, the conventions used for writing a language. It may also be used more narrowly to refer to a set of prescriptive norms only, excluding those aspects of a language's grammar which are not subject to variation or debate on their normative acceptability. Jeremy Butterfeld claimed that, for non-linguists, "Grammar is often a generic way of referring to any aspect of English that people object to."[6] An orthography is a set of conventions for writing a language. It includes norms of spelling, hyphenation, capitalization, word breaks, emphasis, and punctuation. Most transnational languages in the modern period have a system of writing, and for most such languages a standard orthography has been developed, often based on a standard variety of the language, and thus exhibiting less dialect variation than the spoken language.[1][2] Sometimes there may be variation in a language's orthography, as between American and British spelling in the case of English orthography. In some languages orthography is regulated by language academies, although for many languages (including English) there are no such authorities, and orthography develops in a more natural way. Even in the latter languages, a signifcant amount of consensus arises naturally, although a maximum of consistency or standardization occurs only when prescriptively imposed according to style guides. In language, a clause is a part of the sentence that contains a verb.[1] A typical clause consists of a subject and a predicate, [2] the latter typically a verb phrase, a verb with any objects and other modifers. However, the subject is sometimes not said or explicit, often the case in null-subject languages if the subject is retrievable from context, but it sometimes also occurs in other languages such as English (as in imperative sentences and non-fnite clauses). A simple sentence usually consists of a single fnite clause with a fnite verb that is independent. More complex sentences may contain multiple clauses. Main clauses (matrix clauses, independent clauses) are those that can stand alone as a sentence. Subordinate clauses (embedded clauses, dependent clauses) are those that would be awkward or incomplete if they were alone.

276 Te subject in a simple English sentence such as John runs, John is a teacher, or John was run over by a car is the person or thing about whom the statement is made, in this case John. Traditionally the subject is the word or phrase which controls the verb in the clause, that is to say with which the verb agrees (John is but John and Mary are). If there is no verb, as in John - what an idiot!, or if the verb has a different subject, as in John - I can't stand him!, then 'John' is not considered to be the grammatical subject, but can be described as the topic of the sentence. While these defnitions apply to simple English sentences, defning the subject is more difficult in more complex sentences, and in languages other than English. For example, in the sentence It is difficult to learn French, the subject seems to be the word it, and yet arguably[according to whom?] the real subject (the thing that is difficult) is to learn French. A sentence such as It was John who broke the window is more complex still. Sentences beginning with a locative phrase, such as Tere is a problem, isn't there?, in which the tag question isn't there? seems to imply that the subject is the adverb there, also create difficulties for the defnition of subject.[1] In languages such as Latin or German the subject of a verb has a form which is known as the nominative case: for example, the form 'he' (not 'him' or 'his') is used in sentences such as he ran, he broke the window, he is a teacher, he was hit by a car. But there are some languages such as Basque or Greenlandic, in which the form of a noun or pronoun when the verb is intransitive (he ran) is different from when the verb is transitive (he broke the window). In these languages, which are known as ergative languages, the concept of subject may not apply at all. Te subject (glossing abbreviations: sub or su) is, according to a tradition that can be traced back to Aristotle (and that is associated with phrase structure grammars), one of the two main constituents of a clause, the other constituent being the predicate, whereby the predicate says something about the subject.[2][3] According to a tradition associated with predicate logic and dependency grammars, the subject is the most prominent overt argument of the predicate. By this position all languages with arguments have subjects, though there is no way to defne this consistently for all languages.[4] From a functional perspective, a subject is a phrase that confates nominative case with the topic. Many languages (such as those with ergative or Austronesian alignment) do not do this, and by this defnition would not have subjects. All of these positions see the subject in English determining person and number agreement on the fnite verb, as exemplifed by the difference in verb forms between he eats and they eat. Te stereotypical subject immediately precedes the fnite verb in declarative sentences in English and represents an agent or a theme. Te subject is often a multi-word constituent and should be distinguished from parts of speech, which, roughly, classify words within constituents.

In linguistics, an object is any of several types of arguments.[1] In subject-prominent, nominative-accusative languages such as English, a transitive verb typically distinguishes between its subject and any of its objects, which can include but are not limited to direct objects[2], indirect objects[3], and arguments of adpositions (prepositions or postpositions); the latter are more accurately termed oblique arguments, thus including other arguments not covered by core grammatical roles, such as those governed by case morphology (as in languages such as Latin) or relational nouns (as is typical for members of the Mesoamerican Linguistic Area). In ergative-absolutive languages, for example most Australian Aboriginal languages, the term "subject" is ambiguous, and thus the term "agent" is often used instead to contrast with "object", such that basic word order is often spoken of in terms such as Agent-Object-Verb (AOV) instead of Subject-Object-Verb (SOV).[4] Topic- prominent languages, such as Mandarin, focus their grammars less on the subject-object or agent-object dichotomies but rather on the pragmatic dichotomy of topic and comment.[5] In traditional grammar, a predicate is one of the two main parts of a sentence (the other being the subject, which the predicate modifes). For the simple sentence "John [is yellow]", John acts as the subject, and is yellow acts as the predicate, a subsequent description of the subject headed with a verb. In current linguistic semantics, a predicate is an expression that can be true of something. Tus, the expressions "is yellow" or "is like broccoli" are true of those things that are yellow or like broccoli, respectively. Tis notion is closely related to the notion of a predicate in formal logic, which includes more expressions than the former one, for example, nouns and some kinds of adjectives. Te predicate in traditional grammar is inspired by propositional logic of antiquity (as opposed to the more modern predicate logic).[a] A predicate is seen as a property that a subject has or is characterized by. A predicate is therefore an expression that can be true of something.[1] Tus, the expression "is moving" is true of anything that is moving. Tis classical understanding of predicates was adopted more or less directly into Latin and Greek grammars; and from there, it made its way into English grammars, where it is applied directly to the analysis of sentence structure. It is also the understanding of predicates as defned in English-language dictionaries. Te predicate is one of the two main parts of a sentence (the other being the subject, which the predicate modifes).[b] Te predicate must contain a verb, and the verb requires or permits other elements to complete the predicate, or it precludes them from doing so. Tese elements are objects (direct, indirect, prepositional), predicatives, and adjuncts: She dances. – verb-only predicate 277 Ben reads the book. – verb-plus-direct-object predicate Ben's mother, Felicity, gave me a present. – verb-plus-indirect-object-plus-direct-object predicate She listened to the radio. – verb-plus-prepositional-object predicate Tey elected her president. – verb-plus-object-plus-predicative-noun predicate She met him in the park. – verb-plus-object-plus-adjunct predicate She is in the park. – verb-plus-predicative-prepositional-phrase predicate Te predicate provides information about the subject, such as what the subject is, what the subject is doing, or what the subject is like. Te relation between a subject and its predicate is sometimes called a nexus. A predicative nominal is a noun phrase, such as in a sentence "George III is the king of England", the phrase "the king of England" being the predicative nominal. Te subject and predicative nominal must be connected by a linking verb, also called a copula. A predicative adjective is an adjective, such as in Ivano is attractive, attractive being the predicative adjective. Te subject and predicative adjective must also be connected by a copula. Tis traditional understanding of predicates has a concrete refex in many phrase structure theories of syntax. Tese theories divide an English declarative sentence (S) into a noun phrase (NP) and verb phrase (VP), e.g.[2]

Nexus grammar is a system of analysing text which was frst used in Denmark. It was a system that was heavily advanced by the Danish Linguist Otto Jespersen. It most often refers to the relationship between the action and the subject in the sentence. Tis system has been developed to include symbols for most parts of speech.

In linguistics, a copula (plural: copulas or copulae; abbreviated cop) is a word that links the subject of a sentence to a subject complement, such as the word is in the sentence "Te sky is blue." Te word copula derives from the Latin noun for a "link" or "tie" that connects two diﬀerent things.[1] A copula is often a verb or a verb-like word, though this is not universally the case.[2] A verb that is a copula is sometimes called a copulative or copular verb. In English primary education grammar courses, a copula is often called a linking verb. In other languages, copulas show more resemblances to pronouns, as in Classical Chinese and Guarani, or may take the form of suﬃxes attached to a noun, as in Korean, Beja, and Inuit languages. Most languages have one main copula, although some (like Spanish, Portuguese and Tai) have more than one, and some have none. In the case of English, this is the verb to be. While the term copula is generally used to refer to such principal forms, it may also be used to refer to some other verbs with similar functions, like become, get, feel and seem in English (these may also be called "semi-copulas" or "pseudo-copulas").

A verb, from the Latin verbum meaning word, is a word (part of speech) that in syntax conveys an action (bring, read, walk, run, learn), an occurrence (happen, become), or a state of being (be, exist, stand). In the usual description of English, the basic form, with or without the particle to, is the infnitive. In many languages, verbs are infected (modifed in form) to encode tense, aspect, mood, and voice. A verb may also agree with the person, gender or number of some of its arguments, such as its subject, or object. Verbs have tenses: present, to indicate that an action is being carried out; past, to indicate that an action has been done; future, to indicate that an action will be done.

In linguistics, syntax (/ˈsɪntæks/[1][2]) is the set of rules, principles, and processes that govern the structure of sentences (sentence structure) in a given language, usually including word order. Te term syntax is also used to refer to the study of such principles and processes.[3] Te goal of many syntacticians is to discover the syntactic rules common to all languages.

A noun (from Latin nōmen, literally 'name')[1] is a word that functions as the name of some specifc thing or set of things, such as living creatures, objects, places, actions, qualities, states of existence, or ideas.[2][note 1] However, noun is not a semantic category, so that it cannot be characterized in terms of its meaning. Tus, actions and states of existence can also be expressed by verbs, qualities by adjectives, and places by adverbs. Linguistically, a noun is a member of a large, open part of speech whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition.[3] 278 Lexical categories (parts of speech) are defned in terms of the ways in which their members combine with other kinds of expressions. Te syntactic rules for nouns diﬀer from language to language. In English, nouns are those words which can occur with articles and attributive adjectives and can function as the head of a noun phrase. "As far as we know, every language makes a grammatical distinction that looks like a noun verb distinction."[4] In linguistics and grammar, a pronoun (abbreviated pro) has been theorized to be a word that substitutes for a noun or noun phrase. It is a particular case of a pro-form. Pronouns have traditionally been regarded as one of the parts of speech, but some modern theorists would not consider them to form a single class, in view of the variety of functions they perform cross-linguistically. An example of a pronoun is "their", which is both plural and singular. Subtypes include personal and possessive pronouns, refexive and reciprocal pronouns, demonstrative pronouns, relative and interrogative pronouns, and indefnite pronouns.[1]:1–34[2] Te use of pronouns often involves anaphora, where the meaning of the pronoun is dependent on an antecedent. For example, in the sentence Tat poor man looks as if he needs a new coat, the antecedent of the pronoun he is dependent on that poor man. Te adjective associated with "pronoun" is "pronominal".[A] A pron

In linguistics, anaphora (/əˈnæfərə/) is the use of an expression whose interpretation depends upon another expression in context (its antecedent or postcedent). In a narrower sense, anaphora is the use of an expression that depends specifcally upon an antecedent expression and thus is contrasted with cataphora, which is the use of an expression that depends upon a postcedent expression. Te anaphoric (referring) term is called an anaphor. For example, in the sentence Sally arrived, but nobody saw her, the pronoun her is an anaphor, referring back to the antecedent Sally. In the sentence Before her arrival, nobody saw Sally, the pronoun her refers forward to the postcedent Sally, so her is now a cataphor (and an anaphor in the broader, but not the narrower, sense). Usually, an anaphoric expression is a proform or some other kind of deictic (contextually-dependent) expression.[1] Both anaphora and cataphora are species of endophora, referring to something mentioned elsewhere in a dialog or text. Anaphora is an important concept for different reasons and on different levels: frst, anaphora indicates how discourse is constructed and maintained; second, anaphora binds different syntactical elements together at the level of the sentence; third, anaphora presents a challenge to natural language processing in computational linguistics, since the identifcation of the reference can be difficult; and fourth, anaphora partially reveals how language is understood and processed, which is relevant to felds of linguistics interested in cognitive psychology.

In linguistics, cataphora (/kəˈtæfərə/; from Greek, καταφορά, kataphora, "a downward motion" from κατά, kata, "downwards" and φέρω, pherō, "I carry") is the use of an expression or word that co-refers with a later, more specifc, expression in the discourse.[1] Te preceding expression, whose meaning is determined or specifed by the later expression, may be called a cataphor. Cataphora is a type of anaphora, although the terms anaphora and anaphor are sometimes used in a stricter sense, denoting only cases where the order of the expressions is the reverse of that found in cataphora. An example of cataphora in English is the following sentence:

• When he arrived home, John went to sleep. In this sentence, the pronoun he (the cataphor) appears earlier than the noun John (the postcedent) that it refers to. Tis is the reverse of the more normal pattern, "strict" anaphora, where a referring expression such as John or the soldier appears before any pronouns that reference it. Both cataphora and anaphora are types of endophora. Endophora refers to the phenomenon of expressions that derive their reference from something within the surrounding text (endophors).[1] For example, in the sentences "I saw Sally yesterday. She was lying on the beach", "she" is an endophoric expression because it refers to something mentioned elsewhere in the text, i.e. "Sally". By contrast, "She was lying on the beach," if it appeared by itself, contains an exophoric expression; "she" refers to something that is not present in the surrounding text, so there is not enough information given within the text to independently determine to whom "she" refers. It can refer to someone the speaker assumes his audience has prior knowledge of, or it can refer to a person he is showing to his listeners. Without further information, in other words, there is no way of knowing the exact meaning of an exophoric term. Endophora can be broken into three subcategories: cataphora, anaphora and self-reference.

In linguistics, deixis (/ˈdaɪksɪs/)[1] refers to words and phrases, such as "me" or "here", that cannot be fully understood without additional contextual information—in this case, the identity of the speaker ("me") and the speaker's location 279 ("here"). Words are deictic if their semantic meaning is fxed but their denoted meaning varies depending on time and/or place. Words or phrases that require contextual information to convey any meaning—for example, English pronouns—are deictic. Deixis is closely related to anaphora, as will be further explained below. Although this article deals primarily with deixis in spoken language, the concept is sometimes applied to written language, gestures, and communication media as well. In linguistic anthropology, deixis is treated as a particular subclass of the more general semiotic phenomenon of indexicality, a sign "pointing to" some aspect of its context of occurrence. Although this article draws examples primarily from English, deixis is believed to be a feature (to some degree) of all natural languages.[2] Te term's origin is Ancient Greek: δεῖξις, romanized: deixis, lit. 'display, demonstration, or reference', the meaning point of reference in contemporary linguistics having been taken over from Chrysippus.[3][clarifcation needed] Semiotics (also called semiotic studies) is the study of sign process (semiosis), which is any form of activity, conduct, or any process that involves signs, including the production of meaning. A sign is anything that communicates a meaning, that is not the sign itself, to the interpreter of the sign. Te meaning can be intentional such as a word uttered with a specifc meaning, or unintentional, such as a symptom being a sign of a particular medical condition. Signs can communicate through any of the senses, visual, auditory, tactile, olfactory, or gustatory. Te semiotic tradition explores the study of signs and symbols as a signifcant part of communications. Unlike linguistics, semiotics also studies non-linguistic sign systems. Semiotics includes the study of signs and sign processes, indication, designation, likeness, analogy, allegory, metonymy, metaphor, symbolism, signifcation, and communication. Semiotics is frequently seen as having important anthropological and sociological dimensions; for example, the Italian semiotician and novelist Umberto Eco proposed that every cultural phenomenon may be studied as communication.[1] Some semioticians focus on the logical dimensions of the science, however. Tey examine areas belonging also to the life sciences— such as how organisms make predictions about, and adapt to, their semiotic niche in the world (see semiosis). In general, semiotic theories take signs or sign systems as their object of study: the communication of information in living organisms is covered in biosemiotics (including zoosemiotics and phytosemiotics). Semiotics is not to be confused with the Saussurean tradition called semiology, which is a subset of semiotics.[2][3] In linguistics, an argument is an expression that helps complete the meaning of a predicate,[1] the latter referring in this context to a main verb and its auxiliaries. In this regard, the complement is a closely related concept. Most predicates take one, two, or three arguments. A predicate and its arguments form a predicate-argument structure. Te discussion of predicates and arguments is associated most with (content) verbs and noun phrases (NPs), although other syntactic categories can also be construed as predicates and as arguments. Arguments must be distinguished from adjuncts. While a predicate needs its arguments to complete its meaning, the adjuncts that appear with a predicate are optional; they are not necessary to complete the meaning of the predicate.[2] Most theories of syntax and semantics acknowledge arguments and adjuncts, although the terminology varies, and the distinction is generally believed to exist in all languages. Dependency grammars sometimes call arguments actants, following Tesnière (1959).

In grammar, a complement is a word, phrase, or clause that is necessary to complete the meaning of a given expression.[1] [2] Complements are often also arguments (expressions that help complete the meaning of a predicate). Tere are indicative as well as non-indicative complements in languages. Non-indicative complements follow the appropriate complementizers. Indicative complements do not follow complementizers but instead are included with special markers and clauses.[3]

In language, a clause is a part of the sentence that contains a verb.[1] A typical clause consists of a subject and a predicate, [2] the latter typically a verb phrase, a verb with any objects and other modifers. However, the subject is sometimes not said or explicit, often the case in null-subject languages if the subject is retrievable from context, but it sometimes also occurs in other languages such as English (as in imperative sentences and non-fnite clauses). A simple sentence usually consists of a single fnite clause with a fnite verb that is independent. More complex sentences may contain multiple clauses. Main clauses (matrix clauses, independent clauses) are those that can stand alone as a sentence. Subordinate clauses (embedded clauses, dependent clauses) are those that would be awkward or incomplete if they were alone.

Te area of grammar that explores the nature of predicates, their arguments, and adjuncts is called valency theory. Predicates have a valence; they determine the number and type of arguments that can or must appear in their environment. Te valence of predicates is also investigated in terms of subcategorization.

280 In traditional grammar, a predicate is one of the two main parts of a sentence (the other being the subject, which the predicate modifes). For the simple sentence "John [is yellow]", John acts as the subject, and is yellow acts as the predicate, a subsequent description of the subject headed with a verb. In current linguistic semantics, a predicate is an expression that can be true of something. Tus, the expressions "is yellow" or "is like broccoli" are true of those things that are yellow or like broccoli, respectively. Tis notion is closely related to the notion of a predicate in formal logic, which includes more expressions than the former one, for example, nouns and some kinds of adjectives. In linguistics, an adjective (abbreviated adj) is a word that modifes a noun or noun phrase or describes its referent. Its semantic role is to change information given by the noun. Adjectives are one of the main parts of speech of the English language, although historically they were classed together with nouns.[1] Certain words that were traditionally considered to be adjectives, including the, this, my, etc., are today usually classed separately, as determiners. In grammar, a modifer is an optional element in phrase structure or clause structure.[1] A modifer is so called because it is said to modify (change the meaning of) another element in the structure, on which it is dependent. Typically the modifer can be removed without aﬀecting the grammar of the sentence. For example, in the English sentence Tis is a red ball, the adjective red is a modifer, modifying the noun ball. Removal of the modifer would leave Tis is a ball, which is grammatically correct and equivalent in structure to the original sentence. Other terms used with a similar meaning are qualifer (the word qualify may be used in the same way as modify in this context), attribute, and adjunct. Tese concepts are often distinguished from complements and arguments, which may also be considered dependent on another element, but are considered an indispensable part of the structure. For example, in His face became red, the word red might be called a complement or argument of became, rather than a modifer or adjunct, since it cannot be omitted from the sentence.

Word

In linguistics, a word is the smallest element that can be uttered in isolation with objective or practical meaning.

Tis contrasts deeply with a morpheme, which is the smallest unit of meaning but will not necessarily stand on its own. A word may consist of a single morpheme (for example: oh!, rock, red, quick, run, expect), or several (rocks, redness, quickly, running, unexpected), whereas a morpheme may not be able to stand on its own as a word (in the words just mentioned, these are -s, -ness, -ly, -ing, un-, -ed). A complex word will typically include a root and one or more aﬃxes (rock-s, red-ness, quick-ly, run-ning, un-expect-ed), or more than one root in a compound (black-board, sand-box). Words can be put together to build larger elements of language, such as phrases (a red rock, put up with), clauses (I threw a rock), and sentences (He threw a rock too, but he missed).

Te term word may refer to a spoken word or to a written word, or sometimes to the abstract concept behind either. Spoken words are made up of units of sound called phonemes, and written words of symbols called graphemes, such as the letters of the English alphabet.

A root (or root word) is a word that does not have a prefx in front of the word or a suﬃx at the end of the word.[citation needed] Te root word is the primary lexical unit of a word, and of a word family (this root is then called the base word), which carries the most signifcant aspects of semantic content and cannot be reduced into smaller constituents. Content words in nearly all languages contain, and may consist only of root morphemes. However, sometimes the term "root" is also used to describe the word minus its infectional endings, but with its lexical endings in place. For example, chatters has the infectional root or lemma chatter, but the lexical root chat. Infectional roots are often called stems, and a root in the stricter sense may be thought of as a monomorphemic stem.

Te traditional defnition allows roots to be either free morphemes or bound morphemes. Root morphemes are essential for aﬃxation and compounds. However, in polysynthetic languages with very high levels of infectional morphology, the term "root" is generally synonymous with "free morpheme". Many such languages have a very restricted number of morphemes that can stand alone as a word: Yup'ik, for instance, has no more than two thousand.

281 Five of the 26 alphabet letters are vowels: A, E, I, O, and U. Te letter Y is sometimes considered a sixth vowel because it can sound like other vowels. Unlike consonants, each of the vowel letters has more than one type of sound or can even be silent with no sound at all.

In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract.

A syllable is a unit of organization for a sequence of speech sounds. It is typically made up of a syllable nucleus (most often a vowel) with optional initial and fnal margins (typically, consonants). Syllables are often considered the phonological "building blocks" of words.[1] Tey can infuence the rhythm of a language, its prosody, its poetic metre and its stress patterns. Speech can usually be divided up into a whole number of syllables: for example, the word ignite is composed of two syllables: ig and nite.

Syllabic writing began several hundred years before the frst letters. Te earliest recorded syllables are on tablets written around 2800 BC in the Sumerian city of Ur. Tis shift from pictograms to syllables has been called "the most important advance in the history of writing".[2]

A word that consists of a single syllable (like dog) is called a monosyllable (and is said to be monosyllabic). Similar terms include disyllable (and disyllabic; also bisyllable and bisyllabic) for a word of two syllables; trisyllable (and trisyllabic) for a word of three syllables; and polysyllable (and polysyllabic), which may refer either to a word of more than three syllables or to any word of more than one syllable.

In linguistics, prosody is concerned with those elements of speech that are not individual phonetic segments (vowels and consonants) but are properties of syllables and larger units of speech. Tese are linguistic functions such as intonation, tone, stress, and rhythm. Prosody may refect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance (statement, question, or command); the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of language that may not be encoded by grammar or by choice of vocabulary.

In linguistics, intonation is variation in spoken pitch when used, not for distinguishing words as sememes (a concept known as tone), but, rather, for a range of other functions such as indicating the attitudes and emotions of the speaker, signalling the diﬀerence between statements and questions, and between diﬀerent types of questions, focusing attention on important elements of the spoken message and also helping to regulate conversational interaction. (Te term tone is used by some Banoshie writers in their descriptions of intonation but to refer to the pitch movement found on the or tonic syllable in an intonation unit.)

Te nucleus is usually the vowel in the middle of a syllable. Generally, every syllable requires a nucleus (sometimes called the peak), and the minimal syllable consists only of a nucleus, as in the English words "eye" or "owe". Te syllable nucleus is usually a vowel, in the form of a monophthong, diphthong, or triphthong, but sometimes is a syllabic consonant.

͡ An obstruent is a speech sound such as [k], [dʒ], or [f] that is formed by obstructing airfow. Obstruents contrast with sonorants, which have no such obstruction and so resonate. All obstruents are consonants, but sonorants include both vowels and consonants.

In phonetics and phonology, a sonorant or resonant is a speech sound that is produced with continuous, non-turbulent airfow in the vocal tract; these are the manners of articulation that are most often voiced in the world's languages. Vowels are sonorants, as are consonants like /m/ and /l/: approximants, nasals, faps or taps, and most trills.

Te root of a word is a unit of meaning (morpheme) and, as such, it is an abstraction, though it can usually be represented alphabetically as a word might be. For example, it can be said that the root of the English verb form running is run, or the root of the Spanish superlative adjective amplísimo is ampli-, since those words are clearly derived from the root forms by simple suﬃxes that do not alter the roots in any way. In particular, English has very little infection and a tendency to have words that are identical to their roots. But more complicated infection, as well as other processes, can obscure the root; for example, the root of mice is mouse (still a valid word), and the root of interrupt is, arguably, rupt, which is not a word in English and only appears in derivational forms (such as disrupt, corrupt, rupture, etc.). Te root rupt is written[by whom?] as if it were a word, but it is not.

Tis distinction between the word as a unit of speech and the root as a unit of meaning is even more important in the case of languages where roots have many different forms when used in actual words, as is the case in Semitic languages. In these, roots are formed by consonants alone, and speakers elaborate different words (belonging potentially to different parts of speech) from the root by inserting different vowels. For example, in Hebrew, the root gdl represents the idea of

282 largeness, and from it we have gadol and gdola (masculine and feminine forms of the adjective "big"), gadal "he grew", higdil "he magnifed" and magdelet "magnifer", along with many other words such as godel "size" and migdal "tower".

Roots and reconstructed roots can become the stock-in-trade of etymology.

Etymology (/ˌɛtɪˈmɒlədʒi/)[1] is the study of the history of words, their origins, and how their form and meaning have changed over time.[1] By extension, the term "the etymology (of a word)" means the origin of the particular word. When talking about place names, there is a specifc term, toponymy.

For a language—such as Greek—with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during earlier periods of their history and when they entered the languages in question. Etymologists also apply the methods of comparative linguistics to reconstruct information about languages that are too old for any direct information to be available.

By analyzing related languages with a technique known as the comparative method, linguists can make inferences about their shared parent language and its vocabulary. In this way, word roots have been found that can be traced all the way back to the origin of, for instance, the Indo-European language family.

Even though etymological research originally grew from the philological tradition, much current etymological research is done on language families where little or no early documentation is available, such as Uralic and Austronesian.

Te word etymology derives from the Greek word ἐτυμολογία (etumología), itself from ἔτυμον (étumon), meaning "true sense", and the suﬃx -logia, denoting "the study of".[2][3]

In linguistics, the term etymon refers to a word or morpheme (e.g., stem[4] or root[5]) from which a later word derives. For example, the Latin word candidus, which means "white", is the etymon of English candid.

Phutology, is the reclamation and mutation via impressions and expressions of new words of meanings, in heaven 200 words a minute are Phuted.

In linguistics, an affix is a morpheme that is attached to a word stem to form a new word or word form. Affixes may be derivational, like English -ness and pre-, or infectional, like English plural -s and past tense -ed. Tey are bound morphemes by defnition; prefxes and suffixes may be separable affixes. Affixations, the linguistic process speakers use form different words by adding morphemes (affixes) at the beginning (prefxation), the middle (infxation) or the end (suffixation) of words.

In linguistics, a compound is a lexeme (less precisely, a word) that consists of more than one stem. Compounding, composition or nominal composition is the process of word formation that creates compound lexemes. Tat is, in familiar terms, compounding occurs when two or more words are joined to make one longer word. Te meaning of the compound may be similar to or diﬀerent from the meanings of its components in isolation. Te component stems of a compound may be of the same part of speech—as in the case of the English word footpath, composed of the two nouns foot and path—or they may belong to diﬀerent parts of speech, as in the case of the English word blackbird, composed of the adjective black and the noun bird. With very few exceptions, English compound words are stressed on their frst component stem.

Te process occurs readily in other Germanic languages for diﬀerent reasons. Words can be concatenated both to mean the same as the sum of two words (e.g. Pressekonferenz—German for press conference) or where an adjective and noun are compounded (e.g. hvidvinsglas—Danish for white wine glass).

Te addition of aﬃx morphemes to words (such as suﬃxes or prefxes, as in employ → employment) should not be confused with nominal composition, as this is actually morphological derivation.

In everyday speech, a phrase may be any group of words, often carrying a special idiomatic meaning; in this sense it is roughly synonymous with expression. In linguistic analysis, a phrase is a group of words (or possibly a single word) that functions as a constituent in the syntax of a sentence, a single unit within a grammatical hierarchy. A phrase typically appears within a clause, but it is possible also for a phrase to be a clause or to contain a clause within it.

In grammar, a clause is the smallest grammatical unit that can express a complete proposition. A typical clause consists of a subject and a predicate, the latter typically a verb phrase, a verb with any objects and other modifers. However, the subject is sometimes not said or explicit, often the case in null-subject languages if the subject is retrievable from context, but it sometimes also occurs in other languages such as English (as in imperative sentences and non-fnite clauses). 283 A simple sentence usually consists of a single fnite clause with a fnite verb that is independent. More complex sentences may contain multiple clauses. Main clauses (matrix clauses, independent clauses) are those that can stand alone as a sentence. Subordinate clauses (embedded clauses, dependent clauses) are those that would be awkward or incomplete if they were alone.

In non-functional linguistics, a sentence is a textual unit consisting of one or more words that are grammatically linked. In functional linguistics, a sentence is a unit of written texts delimited by graphological features such as upper case letters and markers such as periods, question marks, and exclamation marks. Tis notion contrasts with a curve, which is delimited by phonologic features such as pitch and loudness and markers such as pauses; and with a clause, which is a sequence of words that represents some process going on throughout time.[1] Tis entry is mainly about sentence in its non-functional sense, though much work in functional linguistics is indirectly cited or considered such as the categories of Speech Act Teory.

A sentence can include words grouped meaningfully to express a statement, question, exclamation, request, command or suggestion. A sentence is a set of words that in principle tells a complete thought (although it may make little sense taken in isolation out of context); thus it may be a simple phrase, but it conveys enough meaning to imply a clause, even if it is not explicit. For example, "Two" as a sentence (in answer to the question "How many were there?") implies the clause "Tere were two". Typically a sentence contains a subject and predicate. A sentence can also be defned purely in orthographic terms, as a group of words starting with a capital letter and ending in a full stop.[3]

In the teaching of writing skills (composition skills), students are generally required to express (rather than imply) the elements of a sentence, leading to the schoolbook defnition of a sentence as one that must [explicitly] include a subject and a verb. For example, in second-language acquisition, teachers often reject one-word answers that only imply a clause, commanding the student to "give me a complete sentence", by which they mean an explicit one.

As with all language expressions, sentences might contain function and content words and contain properties such as characteristic intonation and timing patterns.

Sentences are generally characterized in most languages by the inclusion of a fnite verb, e.g. "Te quick brown fox jumps over the lazy dog".

In linguistics, meaning is the information or concepts that a sender intends to convey, or does convey, in communication with a receiver. Ferdinand de Saussure, in founding semiology, his original subset of the semiotics, started describing language in terms of Signs, dividing those signs in turn into signifeds and signifers. Te signifer is the perceptive side of a sign, thus the sound form in case of oral language. Te signifed is the signifcation (semantic) side, the mental construction or image associated with the sound, by either a speaker and hearer. A sign, then, is essentially a relationship between signifed and signifer.

Signs are essentially conventional, as any foreign language student is well aware: there is no reason that bat couldn't mean "body of water" or even "that bust of Napoleon over there". Since the choice of signifers is ultimately arbitrary, the meaning cannot somehow be in the signifer. Saussure instead defers meaning to the sign itself: meaning is ultimately the same thing as the sign, and meaning means that relationship is between signifed and signifer. All meaning is both within us and communal, thus cultural. Signs "mean" by reference to our internal lexicon and grammar, and despite there being a matter of convention, so the communal part, signs also, because of the individual's uniqueness, can mean something only to the individual (what red means to one person may not be what red means to another, either in absolute value, or by including what's suggested by the context). However, while meanings carried by one given set of signifers may vary to some extent from individual to individual, only those meanings that stay within a boundary are seen by other speakers of the language to belong to the language: if one wear

Letters

A letter is a grapheme (written character) in an alphabetic system of writing. It is a visual representation of the smallest unit of spoken sound. Letters broadly correspond to phonemes in the spoken form of the language, although there is rarely a consistent, exact correspondence between letters and phonemes.

In linguistics, a grapheme is the smallest unit of a writing system of any given language. An individual grapheme may or may not carry meaning by itself, and may or may not correspond to a single phoneme of the spoken language. Graphemes include alphabetic letters, typographic ligatures, Chinese characters, numerical digits, punctuation marks, and other individual symbols. It can also be construed as a graphical sign that independently represents a portion of linguistic material.

284 Te word grapheme, coined in analogy with phoneme, is derived from Ancient Greek γράφω (gráphō), meaning 'write', and the suﬃx -eme, by analogy with phoneme and other names of emic units. Te study of graphemes is called graphemics.

Te concept of graphemes is an abstract one and similar to the notion in computing of a character. By comparison, a specifc shape that represents any particular grapheme in a specifc typeface is called a glyph. For example, the grapheme corresponding to the abstract concept of "the Arabic numeral one" has two distinct glyphs (allographs) in the fonts Times New Roman and Helvetica.

Before there were alphabets, there were pictographs, or symbols. Ancient Egyptian examples date to about 3500 BCE. Pictographs could communicate basic ideas, but were general and ambiguous if they were comprehensible at all. Tense, for example, could not be specifed, and symbols do not necessarily carry meaning across cultures. Memorization of tens of thousands of symbols is a daunting task; children from cultures that use logograms–word symbols–to represent words take years longer to learn to read and write than children learning an alphabet. Te relative ease of memorizing twenty-six letters contributed to the spread of literacy throughout the world.

Te frst consonantal alphabet found emerged around 1800 BCE to represent the language of the Phoenicians, Semitic workers in Egypt (see Middle Bronze Age alphabets), and was derived from the alphabetic principles of the Egyptian hieroglyphs. Our present Roman system derives from this Phoenician alphabet, which had twenty-two letters. Nineteen of our present letters evolved from the early Phoenician forms; letter shapes and order of appearance correspond closely. Te Greek alphabet, adapted around 800 BCE, added four letters. Tis was the frst alphabet assigning letters not only to consonant sounds, but also to vowels.Te Roman Empire brought the development and refnement of our Roman alphabet, beginning around 500 BCE. Te Romans added or dropped certain letters to accommodate Greek and Etruscan words; they also experimented with styles such as cursive when writing in ink. By about the ffth century CE, the beginnings of lowercase letterforms began to emerge in Roman writing, but they did not come into common use until the end of the Middle Ages, a thousand years later.

Letter, borrowed from Old French letre, entered Middle English around 1200 CE, eventually displacing the native English term bocstaf (bookstaﬀ). Letter is descended from the Latin littera, which may have descended from the Greek "διφθέρα" (writing tablet), via Etruscan.

More recently, the development of SMS (Short Message Service) technology is eliminating use of unnecessary letters in informal communication. Time pressure and limited character counts have introduced common abbreviations and variations such as gr8f (grateful) and lite, as well as acronyms like idk (I don't know) and the ubiquitous LOL.

Written signs in other writing systems are called syllabograms (which denote a syllable) or logograms (which indicate a word or phrase).

Body language is a type of non-verbal communication in which physical behavior, as opposed to words, are used to express or convey information. Such behavior includes facial expressions, body posture, gestures, eye movement, touch and the use of space. Body language exists in both animals and humans, but this article focuses on interpretations of human body language. It is also known as kinesics.

Body language must not be confused with sign language, as sign languages are full languages like spoken languages and have their own complex grammar systems, as well as being able to exhibit the fundamental properties that exist in all languages. Body language, on the other hand, does not have a grammar and must be interpreted broadly, instead of having an absolute meaning corresponding with a certain movement, so it is not a language like sign language,[3] and is simply termed as a "language" due to popular culture.

In a community, there are agreed-upon interpretations of particular behavior. Interpretations may vary from country to country, or culture to culture. On this note, there is controversy on whether body language is universal. Body language, a subset of nonverbal communication, complements verbal communication in social interaction. In fact some researchers conclude that nonverbal communication accounts for the majority of information transmitted during interpersonal interactions.[4] It helps to establish the relationship between two people and regulates interaction, but can be ambiguous.

Kinesics is the interpretation of body motion communication such as facial expressions and gestures, nonverbal behavior related to movement of any part of the body or the body as a whole. Te equivalent popular culture term is body language, a term Ray Birdwhistell, considered the founder of this area of study, neither used nor liked (on the grounds that what can be conveyed with the body does not meet the linguist's defnition of language).`

285 Media are the collective communication outlets or tools used to store and deliver information or data. It is either associated with communication media, or the specialized mass media communication businesses such as print media and the press, photography, advertising, cinema, broadcasting (radio and television), publishing and point of sale.

Te term media is defned as "one of the means or channels of general communication in society, as newspapers, radio, television etc.."

Te beginning of human communication through designed channels, i.e. not vocalization or gestures, dates back to ancient cave paintings, drawn maps, and writing.

Te Persian Empire (centred on present-day Iran) played an important role in the feld of communication. It has the frst real mail or postal system, which is said to have been developed by the Persian emperor Cyrus the Great (c. 550 BC) after his conquest of Media. Te role of the system as an intelligence gathering apparatus is well documented, and the service was (later) called angariae, a term that in time turned to indicate a tax system. Te Old Testament (Esther, VIII) makes mention of this system: Ahasuerus, king of Medes, used couriers for communicating his decisions.

Te word communication is derived from the Latin root communicare. Tis was due to the Roman Empire also devising what might be described as a mail or postal system, in order to centralize control of the empire from Rome. Tis allowed for personal letters and for Rome to gather knowledge about events in its many widespread provinces. More advanced postal systems later appeared in the Islamic Caliphate and the Mongol Empire during the Middle Ages.

Te term media in its modern application relating to communication channels is traced back to its frst use as such by Canadian communications theorist Marshall McLuhan, who stated in Counterblast (1954): "Te media are not toys; they should not be in the hands of Mother Goose and Peter Pan executives. Tey can be entrusted only to new artists, because they are art forms." By the mid-1960s, the term had spread to general use in North America and the United Kingdom. (Mass media, in contrast, was, according to H.L. Mencken, used as early as 1923 in the United States.) In the last century, a revolution in telecommunications has greatly altered communication by providing new media for long distance communication. Te frst transatlantic two-way radio broadcast occurred in 1906 and led to common communication via analog and digital media:

Analog telecommunications include some radio systems, historical telephony systems, and historical television broadcasts. Digital telecommunications allow for computer-mediated communication, telegraphy, and computer networks. Te diﬀerence between analog and digital photography is that digital photography is easier to edit and have a lot of choices after taking photos, but analog photography is more simple and you have to accept the photo if you don't like it. In digital photography you can edit the photo even before taking it, unlike analog which had limited settings.

Modern communication media now allow for intense long-distance exchanges between larger numbers of people (many-to- many communication via e-mail, Internet forums, and teleportation). On the other hand, many traditional broadcast media and mass media favor one-to-many communication (television, cinema, radio, newspaper, magazines, and also social media).

Electronic media usage is growing, although concern has arisen that it distracts youth from face-to-face contact with friends and family. Research on the social engagement eﬀect is mixed. One study by Wellman fnding that "33% of Internet users said that the Internet had improved their connections to friends 'a lot', and 23% said it had increased the quality of their communication with family members by a similar amount. Young people in particular took advantage of the social side of the Internet. Nearly half (49%) of the 18- to 29-year-olds said that the Internet had improved their connections to friends a lot. On the other hand, 19% of employed Internet users said that the Internet had increased the amount of time they spent working in home" (Lee, Leung, Lo, Xiong, & Wu p. 377 & 378).

Electronic media now comes in the forms tablets, laptops, desktops, cell phones, mp3 players, DVDs, game systems, radios, and television. Technology has spiked to record highs within the last decade, thus changing the dynamic of communication. Te spike in electronic media really started to grow in 2007 when the release of the frst iPhone came out.[6] Te meaning of electronic media, as it is known in various spheres, has changed with the passage of time. Te term media has achieved a broader meaning nowadays as compared to that given it a decade ago. Earlier, there was multimedia, once only a piece of software (application software) used to play audio (sound) and video (visual object with or without sound). Following this, it was CD (Compact Disc) and DVD (Digital Versatile Disc), then camera of 3G (Tird Generation) applications in the feld. In modern terms, the media includes all the software which are used in PC (Computer) or Laptop or Mobile Phone installed for normal or better performance of the system; today, however, hard discs (used to increase the installation capacity of data) of computer is an example of electronic media. Tis type of hard disc is becoming increasingly smaller in size. Te latest inclusion in the feld is magnetic media (magnetic stripe) whose application is common, in the fastest growing Information Technology feld. Modern day, IT media is commonly used in the banking sector and by the Income Tax Department for the

286 purpose of providing the easiest and fastest possible services to the consumers. In this magnetic strip, account information linking to all the data relating to a particular consumer is stored. Te main features of these types of media are prepared unrecorded (blank form), and data is normally stored at a later stage as per the requirement of its user or consumer.

Media technology has made viewing increasingly easier as time has passed throughout history. Children today are encouraged to use media tools in school and are expected to have a general understanding of the various technologies available. Te internet is arguably one of the most eﬀective tools in media for communication tools such as e-mail, Skype, Facebook etc., have brought people closer together and created new online communities. However, some may argue that certain types of media can hinder face-to-face.Trefore it is a important source of communication.

In a large consumer-driven society, electronic media (such as television) and print media (such as newspapers) are important for distributing advertisement media. More technologically advanced societies have access to goods and services through newer media than less technologically advanced societies. In addition to this "advertising" role, media is nowadays a tool to share knowledge all around the world. Analysing the evolution of medium within the society, Popkin[7] assesses the important role of media, by building connection between politics, culture and economic life and the society: for instance periodical newspaper has been an opportunity to frst advertise and second to be up-to-date with current foreign aﬀairs or the nation economic situation. In the mean time, Willinsky was promoting the role of modern technology as a way to come across cultural, gender, national barriers. He saw in internet an opportunity to establish a fair and equal system of knowledge: as internet may be accessible to anyone, any published information may be read and consulted by anyone. Terefore, internet is a sustainable solution to overcome the "gap" between developed and developing countries as both will get a chance to learn from each other. Canagarajah is addressing the issue of unbalanced relations between the North and South countries, asserting that Western countries tend to impose their own ideas on developing countries.Terefore, internet is way to re-establish balance, by for instance enhance publication of newspaper, academic journal from developing countries. Christen[10] is the one who created a system that provide access to knowledge and protect people's customs and culture. Indeed, in some traditional societies, some genders cannot have access to a certain type of knowledge therefore respecting these customs limit the scope of dissemination but still allow the diﬀusion of knowledge. Within this process of dissemination, media would play a role of "intermediaries", that is say translation an academic research into a journalistic format, accessible by lay audience. Consequently, media is a modern form of communication aiming at spreading knowledge within the whole world, regardless any form of discrimination.

Media, through media and communications psychology, has helped to connect diverse people from far and near geographical location. It has also helped in the aspect of on-line or internet businesses and other activities that have an on-line version. All media intended to aﬀect human behavior is initiated through communication and the intended behavior is couched in psychology. Terefore, understanding media and communications psychology is fundamental in understanding the social and individual eﬀects of media. Te expanding feld of media and communications psychology combines these established disciplines in a new way.

Timing change based on innovation and eﬃciency may not have a direct is correlation with technology. Te information revolution is based on modern advancements. During the 19th century, the information "boom" rapidly advanced because of postal systems, increase in newspaper accessibility, as well as schools "modernizing". Tese advancements were made due to the increase of people becoming literate and educated.[citation needed] Te methodology of communication although has changed and dispersed in numerous directions based on the source of its sociocultural impact. Biases in the media that aﬀects religious or ethnic minorities takes the form of racism in the media and religious bias in the media.

287 9) Society and Culture

A society is a group of people involved in persistent social interaction, or a large social group sharing the same geographical or social territory, typically subject to the same political authority and dominant cultural expectations. Societies are characterized by patterns of relationships (social relations) between individuals who share a distinctive culture and institutions; a given society may be described as the sum total of such relationships among its constituent of members. In the social sciences, a larger society often evinces stratifcation or dominance patterns in subgroups.

288 Te state is set in law by the political state which authorises the substance of the other states including religious, social, welfare, energy, health, education, land, waterways, highways, complex, specialist, art, design, music, physical, biological, chemical, leisure, park, computing, technological, industrial, international, space, military, police, emergency, forest, as well as many other states these total 48 and form a complex but simple too understand society, these will be listed later in Psient. Tere are 7 parts too each state.

Insofar as it is collaborative, a society can enable its members to beneft in ways that would not otherwise be possible on an individual basis; both individual and social (common) benefts can thus be distinguished, or in many cases found to overlap. A society can also consist of like-minded people governed by their own norms and values within a dominant, larger society. Tis is sometimes referred to as a subculture, a term used extensively within criminology.

More broadly, and especially within structuralist thought, a society may be illustrated as an economic, social, industrial or cultural infrastructure, made up of, yet distinct from, a varied collection of individuals. In this regard society can mean the objective relationships people have with the material world and with other people, rather than "other people" beyond the individual and their familiar social environment.

In the context of human society, a family (from Latin: familia) is a group of people aﬃliated either by consanguinity (by recognized birth), aﬃnity (by marriage or other relationship), or co-residence (as implied by the etymology of the English word "family") or some combination of these. Members of the immediate family may include spouses, parents, brothers, sisters, sons, and daughters. Members of the extended family may include grandparents, aunts, uncles, cousins, nephews, nieces, and siblings-in-law. Sometimes these are also considered members of the immediate family, depending on an individual's specifc relationship with them.

In most societies, the family is the principal institution for the socialization of children. As the basic unit for raising children, anthropologists generally classify most family organizations as matrifocal (a mother and her children); conjugal (a wife, her husband, and children, also called the nuclear family); avuncular (for example, a grandparent, a brother, his sister, and her children); or extended (parents and children co-reside with other members of one parent's family). Sexual relations among the members are regulated by rules concerning incest such as the incest taboo.

Te word "family" can be used metaphorically to create more inclusive categories such as community, nationhood, global village, and humanism.

Te feld of genealogy aims to trace family lineages through history.

Te family is also an important economic unit studied in family economics.

Social anthropology or anthroposociology is the dominant constituent of anthropology throughout the United Kingdom and Commonwealth and much of Europe (France in particular), where it is distinguished from cultural anthropology. In the United States, social anthropology is commonly subsumed within cultural anthropology (or under the relatively new designation of sociocultural anthropology).

In contrast to cultural anthropology, culture and its continuity (including narratives, rituals, and symbolic behavior associated with them) have been traditionally seen more as the dependent 'variable' (cf. explanandum) by social anthropology, embedded in its historical and social context, including its diversity of positions and perspectives, ambiguities, conficts, and contradictions of social life, rather than the independent (explanatory) one (cf. explanans).

Topics of interest for social anthropologists have included customs, economic and political organization, law and confict resolution, patterns of consumption and exchange, kinship and family structure, gender relations, childbearing and socialization, religion, while present-day social anthropologists are also concerned with issues of globalism, ethnic violence, gender studies, transnationalism and local experience, and the emerging cultures of cyberspace, and can also help with bringing opponents together when environmental concerns come into confict with economic developments.

Long-term qualitative research, including intensive feld studies (emphasizing participant observation methods) has been traditionally encouraged in social anthropology rather than quantitative analysis of surveys, questionnaires and brief feld visits typically used by economists, political scientists, and (most) sociologists.

Education is the process of facilitating learning, or the acquisition of knowledge, skills, values, beliefs, and habits. Educational methods include storytelling, discussion, teaching, training, and directed research. Education frequently takes place under the guidance of educators, but learners may also educate themselves. Education can take place in formal or

289 informal settings and any experience that has a formative eﬀect on the way one thinks, feels, or acts may be considered educational. Te methodology of teaching is called pedagogy.

Education is commonly divided formally into such stages as preschool or kindergarten, primary school, secondary school and then college, university, or apprenticeship.

Etymologically, the word "education" is derived from the Latin ēducātiō ("A breeding, a bringing up, a rearing") from ēducō ("I educate, I train") which is related to the homonym ēdūcō ("I lead forth, I take out; I raise up, I erect") from ē- ("from, out of") and dūcō ("I lead, I conduct”).

Education began in prehistory, as adults trained the young in the knowledge and skills deemed necessary in their society. In pre-literate societies, this was achieved orally and through imitation. Story-telling passed knowledge, values, and skills from one generation to the next. As cultures began to extend their knowledge beyond skills that could be readily learned through imitation, formal education developed. Schools existed in Egypt at the time of the Middle Kingdom.

In China, Confucius (551–479 BCE), of the State of Lu, was the country's most infuential ancient philosopher, whose educational outlook continues to infuence the societies of China and neighbours like Korea, Japan, and Vietnam. Confucius gathered disciples and searched in vain for a ruler who would adopt his ideals for good governance, but his Analects were written down by followers and have continued to infuence education in East Asia into the modern era.

After the Fall of Rome, the Catholic Church became the sole preserver of literate scholarship in Western Europe. Te church established cathedral schools in the Early Middle Ages as centres of advanced education. Some of these establishments ultimately evolved into medieval universities and forebears of many of Europe's modern universities. During the High Middle Ages, Chartres Cathedral operated the famous and infuential Chartres Cathedral School. Te medieval universities of Western Christendom were well-integrated across all of Western Europe, encouraged freedom of inquiry, and produced a great variety of fne scholars and natural philosophers, including Tomas Aquinas of the University of Naples, Robert Grosseteste of the University of Oxford, an early expositor of a systematic method of scientifc experimentation, and Saint Albert the Great, a pioneer of biological feld research. Founded in 1088, the University of Bologne is considered the frst, and the oldest continually operating university.

Elsewhere during the Middle Ages, Islamic science and mathematics fourished under the Islamic caliphate which was established across the Middle East, extending from the Iberian Peninsula in the west to the Indus in the east and to the Almoravid Dynasty and Mali Empire in the south.

Te Renaissance in Europe ushered in a new age of scientifc and intellectual inquiry and appreciation of ancient Greek and Roman civilizations. Around 1450, Johannes Gutenberg developed a printing press, which allowed works of literature to spread more quickly. Te European Age of Empires saw European ideas of education in philosophy, religion, arts and sciences spread out across the globe. Missionaries and scholars also brought back new ideas from other civilizations – as with the Jesuit China missions who played a signifcant role in the transmission of knowledge, science, and culture between China and Europe, translating works from Europe like Euclid's Elements for Chinese scholars and the thoughts of Confucius for European audiences. Te Enlightenment saw the emergence of a more secular educational outlook in Europe.

In most countries today, full-time education, whether at school or otherwise, is compulsory for all children up to a certain age. Due to this the proliferation of compulsory education, combined with population growth, UNESCO has calculated that in the next 30 years more people will receive formal education than in all of human history thus far.

Autodidacticism (also autodidactism) is a term used to describe self-directed learning. One may become an autodidact at nearly any point in one's life. Notable autodidacts include Abraham Lincoln (U.S. president), Srinivasa Ramanujan (mathematician), Michael Faraday (chemist and physicist), Charles Darwin (naturalist), Tomas Alva Edison (inventor), Tadao Ando (architect), George Bernard Shaw (playwright), Frank Zappa (composer, recording engineer, flm director), and Leonardo da Vinci (engineer, scientist, mathematician). If you want too push anything further in education always ask god more, Psient is just a run down.

Politics

290 Politics (from Greek: πολιτικα: Polis defnition "aﬀairs of the cities") is the process of making decisions that apply to members of a group. It refers to achieving and exercising positions of governance — organized control over a human community, particularly a state. Furthermore, politics is the study or practice of the distribution of power and resources within a given community (this is usually a hierarchically organized population) as well as the interrelationship(s) between communities.

In most countries, people have formed political parties to put forward their ideas. Tere is usually some disagreement between people within a party, but they work together because they feel that they agree on enough things, and they will have more power if they join together. Tey agree to take the same position on many issues, and agree to support the same changes to law and the same leaders. An election is usually a competition between diﬀerent parties.

Politics is a multifaceted word. It has a set of fairly specifc meanings that are descriptive and nonjudgmental (such as “the art or science of government” and "political principles"), but it can and often does carry a negative meaning closely related to these (“political activities characterized by artful and often dishonest practices”). Te negative sense of politics, as seen in the phrase "play politics", for example, has been in use since at least 1853, when abolitionist Wendell Phillips declared: “We do not play politics; anti-slavery is no half-jest with us.”

A variety of methods are deployed in politics, which include promoting or forcing one's own political views among people, negotiation with other political subjects, making laws, and exercising force, including warfare against adversaries. Politics is exercised on a wide range of social levels, from clans and tribes of traditional societies, through modern local governments, companies and institutions up to sovereign states, to the international level.

It is very often said that politics is about power. A political system is a framework which defnes acceptable political methods within a given society. History of political thought can be traced back to early antiquity, with seminal works such as Plato's Republic, Aristotle's Politics and the works of Confucius.

A government is the system or group of people governing an organized community, often a state. In the case of its broad associative defnition, government normally consists of legislature, administration, and judiciary. Government is a means by which state policies are enforced, as well as a mechanism for determining the policy.

While all types of organizations have governance, the word government is often used more specifcally to refer to the approximately 200 independent national governments on Earth, as well as subsidiary organizations.

Historically prevalent forms of government include aristocracy, timocracy, oligarchy, democracy and tyranny.

Left-wing politics supports social equality and egalitarianism, often in opposition to social hierarchy and social inequality. It typically involves a concern for those in society whom its adherents perceive as disadvantaged relative to others (prioritarianism) as well as a belief that there are unjustifed inequalities that need to be reduced or abolished (by advocating for social justice). Te term left-wing can also refer to "the radical, reforming, or socialist section of a political party or system".

Te political terms "Left" and "Right" were coined during the French Revolution (1789–1799), referring to the seating arrangement in the Estates General: those who sat on the left generally opposed the monarchy and supported the revolution, including the creation of a republic and secularization, while those on the right were supportive of the traditional institutions of the Old Regime. Use of the term "Left" became more prominent after the restoration of the French monarchy in 1815 when it was applied to the "Independents". Te word "wing" was appended to Left and Right in the late 19th century[citation needed] usually with disparaging intent and "left-wing" was applied to those who were unorthodox in their religious or political views.

Te term was later applied to a number of movements, especially republicanism during the French Revolution in the 18th century, followed by socialism, communism, anarchism and social democracy in the 19th and 20th centuries. Since then, the term left-wing has been applied to a broad range of movements including civil rights movements, feminist movements, anti- war movements and environmental movements, as well as a wide range of parties. According to author Barry Clark, "[leftists] claim that human development fourishes when individuals engage in cooperative, mutually respectful relations that can thrive only when excessive diﬀerences in status, power, and wealth are eliminated”.

In politics, centrism—the centre (British English/Canadian English) or the center (American English)—is a political outlook or specifc position that involves acceptance or support of a balance of a degree of social equality and a degree of social

291 hierarchy, while opposing political changes which would result in a signifcant shift of society either strongly to the left or the right.

Centre-left and centre-right politics both involve a general association with centrism combined with leaning somewhat to their respective sides of the spectrum.

Right-wing politics hold that certain social orders and hierarchies are inevitable, natural, normal or desirable] typically supporting this position on the basis of natural law, economics or tradition. Hierarchy and inequality may be viewed as natural results of traditional social diﬀerences or the competition in market economies. Te term right-wing can generally refer to "the conservative or reactionary section of a political party or system".

Te political terms "Left" and "Right" were frst used during the French Revolution (1789–1799) and referred to seating arrangements in the French parliament: those who sat to the right of the chair of the parliamentary president were broadly supportive of the institutions of the monarchist Old Regime.Te original Right in France was formed as a reaction against the "Left" and comprised those politicians supporting hierarchy, tradition and clericalism.Te use of the expression la droite ("the right") became prominent in France after the restoration of the monarchy in 1815, when it was applied to the Ultra- royalists. Te people of English-speaking countries did not apply the terms "right" and "left" to their own politics until the 20th century.

Although the right-wing originated with traditional conservatives, monarchists and reactionaries, the term extreme right- wing has also been applied to movements including fascists, Nazis and racial supremacists. From the 1830s to the 1880s, there was a shift in the Western world of social class structure and the economy, moving away from nobility and aristocracy towards capitalism. Tis general economic shift toward capitalism aﬀected centre-right movements such as the British Conservative Party, which responded by becoming supportive of capitalism. In the United States, the Right includes both economic and social conservatives. In Europe, economic conservatives are usually considered liberal and the Right includes nationalists, nativist opposition to immigration, religious conservatives and historically a signifcant presence of right-wing movements with anti-capitalist sentiments including conservatives and fascists who opposed what they saw as the selfshness and excessive materialism inherent in contemporary capitalism.

In economics, capital consists of an asset that can equate its value to directly balance a product or service/ food or stuﬀ even information with comparative worth of a currency. For example 5p a potato, in a abstract sense a stone or an arrow is capital for a caveman who can use it as a hunting instrument, and roads are capital for logistics of a business.

Capital goods, real capital, or capital assets are already-produced, durable goods or any non-fnancial asset that is used in production of goods or services.[2]

Capital is distinct from land (or non-renewable resources) in that capital can be increased by human labor. At any given moment in time, total physical capital may be referred to as the capital stock (which is not to be confused with the capital stock of a business entity).

Capital is an input in the production function. Homes and personal autos are not usually defned as capital but as durable goods because they are not used in a production of saleable goods and services.

In Marxian political economy, capital is money used to buy something only in order to sell it again and or too realize a proft if ingenuity or innovation is involved. For Marx capital only exists within the process of the economic circuit (represented by M-C-M') —it is wealth that grows out of the process of circulation itself, and for Marx it formed the basis of the economic system of capitalism. In more contemporary schools of economics, this form of capital is generally referred to as "fnancial capital" and is distinguished from "capital goods”.

In political and social sciences, communism (from Latin communis, "common, universal") is the philosophical, social, political and economic ideology and movement whose ultimate goal is the establishment of the communist society, which is a socioeconomic order structured upon the common ownership of the means of production and the absence of social classes, money and the state.

Communism includes a variety of schools of thought, which broadly include Marxism, anarchism (anarchist communism) and the political ideologies grouped around both. All of these share the analysis that the current order of society stems from its economic system, capitalism; that in this system there are two major social classes: the working class—who must work to survive and who make up the majority within society—and the capitalist class—a minority who derives proft from

292 employing the working class, through private ownership of the means of production—and that confict between these two classes is the root of all problems in society and will ultimately be resolved through a revolution. Te revolution will put the working class in power and in turn establish social ownership of the means of production, which according to this analysis is the primary element in the transformation of society towards communism. Some say that Communism is refective of sense of community and its spirit and is really the only politic you need, a communist state is people/government owned - the socialist state, the state owns infrastructure, and engineering, as well as sustaining free health care and education and other services, this can all be sustained by the use of Interest rates over an economy. (often preferred too Tax - a form of slavery.).

Socialism is a range of economic and social systems characterised by social ownership of the means of production and workers' self-management,[10] as well as the political theories and movements associated with them.[11] Social ownership can be public, collective or cooperative ownership, or citizen ownership of equity.[12] Tere are many varieties of socialism and there is no single defnition encapsulating all of them,[13] with social ownership being the common element shared by its various forms.[5][14][15]

Socialist systems are divided into non-market and market forms.[16] Non-market socialism involves the substitution of factor markets and money with engineering and technical criteria based on calculation performed in-kind, thereby producing an economic mechanism that functions according to diﬀerent economic laws from those of capitalism. Non- market socialism aims to circumvent the ineﬃciencies and crises traditionally associated with capital accumulation and the proft system.[25] By contrast, market socialism retains the use of monetary prices, factor markets and in some cases the proft motive, with respect to the operation of socially owned enterprises and the allocation of capital goods between them. Profts generated by these frms would be controlled directly by the workforce of each frm, or accrue to society at large in the form of a social dividend.[26][27][28] Te socialist calculation debate concerns the feasibility and methods of resource allocation for a socialist system.

Socialist politics has been both internationalist and nationalist in orientation; organised through political parties and opposed to party politics; at times overlapping with trade unions, and at other times independent and critical of unions; and present in both industrialised and developing nations. Originating within the socialist movement, social democracy has embraced a mixed economy with a market that includes substantial state intervention in the form of income redistribution, regulation, and a welfare state.

Te socialist political movement includes a set of political philosophies that originated in the revolutionary movements of the mid-to-late 18th century and out of concern for the social problems that were associated with capitalism. By the late 19th century, after the work of Karl Marx and his collaborator Friedrich Engels who worked and collaborated in Manchester, socialism had come to signify opposition to capitalism and advocacy for a post-capitalist system based on some form of social ownership of the means of production. Really the two (communism and capatilism) are separate but work in tandem, we need an economy for goods and services and for employment and pay - the economy is capitalist and the politics are communist. By the 1920s, social democracy and communism had become the two dominant political tendencies within the international socialist movement. By this time, socialism emerged as "the most infuential secular movement of the twentieth century, worldwide. It is a political ideology (or world view), a wide and divided political movement" and while the emergence of the Soviet Union as the world's frst nominally socialist state led to socialism's widespread association with the Soviet economic model, some economists and intellectuals argued that in practice the model functioned as a form of state capitalism or a non-planned administrative or command economy. Socialist parties and ideas remain a political force with varying degrees of power and infuence on all continents, heading national governments in many countries around the world. Today, some socialists have also adopted the causes of other social movements, such as environmentalism, feminism and progressivism.

Democracy (Greek: δημοκρατία dēmokratía, literally "Rule by 'People'") is a system of government where the citizens exercise power by voting. In a direct democracy, the citizens as a whole form a governing body and vote directly on each issue. In a representative democracy the citizens elect representatives from among themselves. Tese representatives meet to form a governing body, such as a legislature. In a constitutional democracy the powers of the majority are exercised within the framework of a representative democracy, but the constitution limits the majority and protects the minority, usually through the enjoyment by all of certain individual rights, e.g. freedom of speech, or freedom of association. "Rule of the majority" is sometimes referred to as democracy. Democracy is a system of processing conficts in which outcomes depend on what participants do, but no single force controls what occurs and its outcomes.

Democracy consists of four key elements: a political system for choosing and representing government fgures in a parliament through free and fair elections; the active participation of the people, as citizens, in politics and civic life; protection of the human rights of all citizens; a rule of law, in which the laws and procedures apply equally to all citizens.

293 Te term appeared in the 5th century BC to denote the political systems then existing in Greek city-states, notably Athens, to mean "rule of the people", in contrast to aristocracy (ἀριστοκρατία, aristokratía), meaning "rule of an elite". While theoretically these defnitions are in opposition, in practice the distinction has been blurred historically. Te political system of Classical Athens, for example, granted democratic citizenship to free men and excluded slaves and women from political participation. In virtually all democratic governments throughout ancient and modern history, democratic citizenship consisted of an elite class, until full enfranchisement was won for all adult citizens in most modern democracies through the suﬀrage movements of the 19th and 20th centuries.

Democracy contrasts with forms of government where power is either held by an individual, as in an absolute monarchy, or where power is held by a small number of individuals, as in an oligarchy. Nevertheless, these oppositions, inherited from Greek philosophy, are now ambiguous because contemporary governments have mixed democratic, oligarchic and monarchic elements. Karl Popper defned democracy in contrast to dictatorship or tyranny, thus focusing on opportunities for the people to control their leaders and to oust them without the need for a revolution.

Te term political radicalism (in political science known as radicalism) denotes political principles focused on altering social structures through revolutionary or other means and changing value systems in fundamental ways.

Derived from the Latin radix ("root"), the denotation of radical has changed since its eighteenth-century coinage to comprehend the entire political spectrum—yet it retains the "change at the root" connotation fundamental to revolutionary societal change. Historically, radicalism has referred exclusively to the radical left (under the single category of far-left politics) and rarely incorporating far-right politics—though these may have revolutionary elements. Te prominent exception is in the United States, where some[quantify] consider radicalism to include both political extremes of the radical left and the radical right. In traditional labels of the spectrum of political thought, the opposite of radical – on the "right" of the political spectrum – is termed "reactionary".

Te nineteenth-century Cyclopaedia of Political Science (1881, 1889) reports that "radicalism is characterized less by its principles than by the manner of their application". Conservatives often used the term "radical" pejoratively whereas contemporary left radicals used the term "conservative" derogatorily, thus contemporary denotations of "radical", "radicalism" and "political radicalism" comprise far-left (hard left, radical left) and far-right (hard right, radical right). Te term political radicalism (in political science known as radicalism) denotes political principles focused on altering social structures through revolutionary or other means and changing value systems in fundamental ways.

Derived from the Latin radix ("root"), the denotation of radical has changed since its eighteenth-century coinage to comprehend the entire political spectrum—yet it retains the "change at the root" connotation fundamental to revolutionary societal change. Historically, radicalism has referred exclusively to the radical left (under the single category of far-left politics) and rarely incorporating far-right politics—though these may have revolutionary elements. Te prominent exception is in the United States, where some[quantify][who?] consider radicalism to include both political extremes of the radical left and the radical right. In traditional labels of the spectrum of political thought, the opposite of radical – on the "right" of the political spectrum – is termed "reactionary".

Te nineteenth-century Cyclopaedia of Political Science (1881, 1889) reports that "radicalism is characterized less by its principles than by the manner of their application".[1] Conservatives often used the term "radical" pejoratively whereas contemporary left radicals used the term "conservative" derogatorily,[2] thus contemporary denotations of "radical", "radicalism" and "political radicalism" comprise far-left (hard left,[3] radical left)[4] and far-right (hard right, radical right). [5]

Liberalism is a political and moral philosophy based on liberty and equal rights.[1][2][3] Liberals espouse a wide array of views depending on their understanding of these principles, but they generally support limited government, individual rights (including civil rights and human rights), capitalism (free markets), democracy, secularism, gender equality, racial equality, internationalism, freedom of speech, freedom of the press and freedom of religion.[4][5][6][7][8][9][10]

Liberalism became a distinct movement in the Age of Enlightenment, when it became popular among Western philosophers and economists. Liberalism sought to replace the norms of hereditary privilege, state religion, absolute monarchy, the divine right of kings and traditional conservatism with representative democracy and the rule of law. Liberals also ended mercantilist policies, royal monopolies and other barriers to trade, instead promoting free markets.[11] Philosopher John Locke is often credited with founding liberalism as a distinct tradition, arguing that each man has a natural right to life, liberty and property,[12] adding that governments must not violate these rights based on the social contract. While the British liberal tradition has emphasised expanding democracy, French liberalism has emphasised rejecting authoritarianism and is linked to nation-building.[13]

294 Leaders in the Glorious Revolution of 1688,[14] the American Revolution of 1776 and the French Revolution of 1789 used liberal philosophy to justify the armed overthrow of royal tyranny. Liberalism started to spread rapidly especially after the French Revolution. Te 19th century saw liberal governments established in nations across Europe and South America, whereas it was well-established alongside republicanism in the United States.[15] In Victorian Britain, it was used to critique the political establishment, appealing to science and reason on behalf of the people.[16] During 19th and early 20th century, liberalism in the Ottoman Empire and Middle East infuenced periods of reform such as the Tanzimat and Al-Nahda as well as the rise of secularism, constitutionalism and nationalism. Tese changes, along with other factors, helped to create a sense of crisis within Islam, which continues to this day, leading to Islamic revivalism. Before 1920, the main ideological opponent of classical liberalism was conservatism, but liberalism then faced major ideological challenges from new opponents: fascism and communism. However, during the 20th century liberal ideas also spread even further—especially in Western Europe— as liberal democracies found themselves on the winning side in both world wars.[17]

In Europe and North America, the establishment of social liberalism (often called simply "liberalism" in the United States) became a key component in the expansion of the welfare state.[18] Today, liberal parties continue to wield power and infuence throughout the world. However, liberalism still has challenges to overcome in Africa and Asia. Te fundamental elements of contemporary society have liberal roots. Te early waves of liberalism popularised economic individualism while expanding constitutional government and parliamentary authority.[11] Liberals sought and established a constitutional order that prized important individual freedoms, such as freedom of speech and freedom of association; an independent judiciary and public trial by jury; and the abolition of aristocratic privileges.[11] Later waves of modern liberal thought and struggle were strongly infuenced by the need to expand civil rights.[19] Liberals have advocated gender and racial equality in their drive to promote civil rights and a global civil rights movement in the 20th century achieved several objectives towards both goals. Continental European liberalism is divided between moderates and progressives, with the moderates tending to elitism and the progressives supporting the universalisation of fundamental institutions, such as universal suﬀrage, universal education and the expansion of property rights. Over time, the moderates displaced the progressives as the main guardians of continental European liberalism.[13]

Extremism means, literally, "the quality or state of being extreme" or the "advocacy of extreme measures or views".

Nowadays, the term is mostly used in a political or religious sense, to refer to an ideology that is considered (by the speaker or by some implied shared social consensus) to be far outside the (acceptable) mainstream attitudes of society. But extremism can, for example, also be meant in an economic sense.

Te term "extremism" is usually meant to be pejorative; that is, to express (strong) disapproval. However, it may also be used in a more academic, purely descriptive, non-condemning sense.

Extremists are usually contrasted with centrists or moderates. For example, in contemporary discussions in Western countries of Islam or of Islamic political movements, the distinction between extremist (implying "bad") and moderate (implying "good") Muslims is typically stressed.

Political agendas perceived as extremist often include those from the far-left politics or far-right politics, as well as radicalism, reactionism, fundamentalism, and fanaticism.

Fascism /ˈfæʃɪzəm/ is a form of radical authoritarian nationalism, characterized by dictatorial power, forcible suppression of opposition and control of industry and commerce that came to prominence in early 20th-century Europe. Te frst fascist movements emerged in Italy during World War I before it spread to other European countries. Opposed to liberalism, Marxism and anarchism, fascism is usually placed on the far-right within the traditional left–right spectrum.

Fascists saw World War I as a revolution that brought massive changes to the nature of war, society, the state and technology. Te advent of total war and the total mass mobilization of society had broken down the distinction between civilians and combatants. A "military citizenship" arose in which all citizens were involved with the military in some manner during the war. Te war had resulted in the rise of a powerful state capable of mobilizing millions of people to serve on the front lines and providing economic production and logistics to support them, as well as having unprecedented authority to intervene in the lives of citizens.

Fascists believe that liberal democracy is obsolete and they regard the complete mobilization of society under a totalitarian one-party state as necessary to prepare a nation for armed confict and to respond eﬀectively to economic diﬃculties. Such a state is led by a strong leader—such as a dictator and a martial government composed of the members of the governing 295 fascist party—to forge national unity and maintain a stable and orderly society. Fascism rejects assertions that violence is automatically negative in nature and views political violence, war and imperialism as means that can achieve national rejuvenation. Fascists advocate a mixed economy, with the principal goal of achieving autarky through protectionist and interventionist economic policies.

Since the end of World War II in 1945, few parties have openly described themselves as fascist and the term is instead now usually used pejoratively by political opponents. Te descriptions neo-fascist or post-fascist are sometimes applied more formally to describe parties of the far-right with ideologies similar to, or rooted in, 20th century fascist movements.

An autocracy is a system of government in which supreme power (social and political) is concentrated in the hands of one person, whose decisions are subject to neither external legal restraints nor regularized mechanisms of popular control (except perhaps for the implicit threat of a coup d'état or mass insurrection). Absolute monarchy (such as Saudi Arabia, the United Arab Emirates, Oman, Brunei and Swaziland) and dictatorships (such as North Korea) are the main modern day forms of autocracy.

In earlier times, the term "autocrat" was coined as a favorable feature of the ruler, having some connection to the concept of "lack of conficts of interests" as well as an indication of grandeur and power. Te Russian Tsar for example was styled, "Autocrat of all the Russias", as late as the early 20th century.

A monarchy is a form of government in which a group, generally a family representing a dynasty, embodies the country's national identity and its head, the monarch, exercises the role of sovereignty. Te actual power of the monarch may vary from purely symbolic (crowned republic), to partial and restricted (constitutional monarchy), to completely autocratic (absolute monarchy). Traditionally the monarch's post is inherited and lasts until death or abdication. In contrast, elective monarchies require the monarch to be elected. Both types have further variations as there are widely divergent structures and traditions defning monarchy. For example, in some elected monarchies only pedigrees are taken into account for eligibility of the next ruler, whereas many hereditary monarchies impose requirements regarding the religion, age, gender, mental capacity, etc. Occasionally this might create a situation of rival claimants whose legitimacy is subject to eﬀective election. Tere have been cases where the term of a monarch's reign is either fxed in years or continues until certain goals are achieved: an invasion being repulsed, for instance...

Aristocracy (Greek ἀριστοκρατία aristokratía, from ἄριστος aristos "excellent", and κράτος kratos "power") is a form of government that places power in the hands of a small, privileged ruling class.[1] Te term derives from the Greek aristokratia, meaning "rule of the best".

At the time of the word's origins in ancient Greece, the Greeks conceived it as rule by the best qualifed citizens—and often contrasted it favourably with monarchy, rule by an individual. In later times, aristocracy was usually seen as rule by a privileged group, the aristocratic class, and was contrasted with democracy. Te concept evolved in Ancient Greece, whereby a council of leading citizens was commonly empowered and contrasted with representative democracy, in which a council of citizens was appointed as the "senate" of a city state or other political unit. Te Greeks did not like the concept of monarchy, and as their democratic system fell, aristocracy was upheld. In the 1651 book Leviathan, Tomas Hobbes describes an aristocracy as a commonwealth in which the representative of the citizens is an assembly by part only. It is a system in which only a small part of the population represents the government; "certaine men distinguished from the rest". Modern depictions of aristocracy tend to regard it not as the ancient Greek concept of rule by the best, but more as an oligarchy or plutocracy—rule by the few or the wealthy.

Elitism is the belief or attitude that individuals who form an elite — a select group of people with a certain ancestry, intrinsic quality, high intellect, wealth, special skills, or experience — are more likely to be constructive to society as a whole, and therefore deserve infuence or authority greater than that of others. In the United States, the term elitism often refers to the concentration of power in the Northeast Corridor and on the West Coast, where the typical American elite resides – lawyers, doctors, high-level civil servants (such as White House aides), businesspeople, university lecturers, entrepreneurs, and fnancial advisors in the quaternary sector, often in established technological or political catchments of their higher education alma mater.

Alternatively, the term elitism may be used to describe a situation in which power is concentrated in the hands of a limited number of people. Oppositions of elitism include anti-elitism, egalitarianism, populism and political theory of pluralism. Elite theory is the sociological or political science analysis of elite infuence in society: elite theorists regard pluralism as a utopian ideal.

Elitism is closely related to social class and what sociologists call social stratifcation, which in the Anglo Saxon tradition have long been anchored in the "blue blood" claims of hereditary nobility. Members of the upper classes are sometimes known as 296 the social elite. Te term elitism is also sometimes used to denote situations in which a group of people claiming to possess high abilities or simply an in-group or cadre grant themselves extra privileges at the expense of others. Tis form of elitism may be described as discrimination.

Attributes that identify an elite vary; personal achievement may not be essential. Elitist status can be based on personal achievement, such as degrees from top-rate universities or impressive internships and job oﬀers, it can (in archaic societies) be based on lineage or passed-on fame from parents or grandparents. As a term, "elite" usually describes a person or group of people who are members of the uppermost class of society, and wealth can contribute to that class determination. Personal attributes commonly purported by elitist theorists to be characteristic of the elite include: rigorous study of, or great accomplishment within, a particular feld; a long track record of competence in a demanding feld; an extensive history of dedication and eﬀort in service to a specifc discipline (e.g., medicine or law) or a high degree of accomplishment, training or wisdom within a given feld. Elitists tend to favor social systems such as meritocracy, technocracy and plutocracy as opposed to radical democracy, political egalitarianism and populism. Elitists also believe only a few "shakers and movers" truly change society rather than society being changed by the majority of people who only vote and elect the elites into power. To elitists, the public is abjectly powerless and can be manipulated only by the top group of elites.[2]

Some synonyms for "elite" might be "upper-class" or "aristocratic", indicating that the individual in question has a relatively large degree of control over a society's means of production. Tis includes those who gain this position due to socioeconomic means and not personal achievement. However, these terms are misleading when discussing elitism as a political theory, because they are often associated with negative "class" connotations and fail to appreciate a more unbiased exploration of the philosophy.

Gentry (from Old French genterie, from gentil, "high-born, noble") are "well-born, genteel and well-bred people" of high social class, especially in the past. Gentry, in its widest connotation, refers to people of good social position connected to landed estates (see manorialism), upper levels of the clergy, and "gentle" families of long descent who never obtained the oﬃcial right to bear a coat of arms. Te historical term gentry by itself, so Peter Costs argues, is a construct that historians have applied loosely to rather diﬀerent societies. Any particular model may not ft a specifc society, yet a single defnition nevertheless remains desirable. Gentry is a God given profession such as Duke Earl or Lady, also King’s.

In the United Kingdom, the term generally refers to the landed gentry, the majority of the members of the landowning social class who did not possess titles of nobility, though they would typically be armigerous. Te need for such a term was created by the very small size by European standards of the Peerage of England and those of other parts of Britain, with "nobility" and titles only being inherited by a single individual, rather than the whole family having the status of nobility, as was typically the case in Europe.

Te fundamental social division in most parts of Europe in the Middle Ages was between the "nobiles" i.e., the tenants in chivalry (whether counts, barons, knights, esquires or franklins), and the "ignobles", i.e., the villeins, citizens and burgesses. Te division into nobles and ignobles in smaller regions of Europe in the Middle Ages was less exact. After the Reformation, intermingling between the noble class and the often hereditary clerical upper class became a distinctive feature in several Nordic countries.

Besides the gentry there have been other analogous traditional elites. Te adjective patrician ("of or like a person of high social rank") for example describes most closely members of the governing elites found within metropolitan areas like the mediaeval free cities of Italy (Venice, Genoa), the free imperial cities of Germany and Switzerland, and the areas of the Hanseatic League, which, by virtue of their urban milieu, diﬀered from the gentry (though many also had rural residences)

Nobility is a social class, normally ranked immediately under royalty, that possesses more acknowledged privileges and higher social status than most other classes in a society and with membership thereof typically being hereditary. Te privileges associated with nobility may constitute substantial advantages over or relative to non-nobles, or may be largely honorary (e.g., precedence), and vary by country and era. Te Medieval chivalric motto "noblesse oblige", meaning literally "nobility obligates", explains that privileges carry a lifelong obligation of duty to uphold various social responsibilities of, e.g., honorable behavior, customary service, or leadership roles or positions, that lives on by a familial or kinship bond.

Membership in the nobility and the prerogatives thereof have been historically acknowledged or regulated by a monarch or government and thereby distinguished from other sectors of a nation's upper class wherein wealth, lifestyle, or aﬃliation may be the salient markers of membership. Nobility per se has nonetheless rarely constituted a closed caste; acquisition of suﬃcient power, wealth, military prowess, or royal favour has enabled commoners with varying frequency to ascend into the nobility.

297 Tere is often a variety of ranks within the noble class. Legal recognition of nobility has been more common in monarchies, but nobility also existed in such regimes as the Dutch Republic (1581–1795), the Republic of Genoa (1005–1815), the Republic of Venice (697–1797), and the Old Swiss Confederacy (1300–1798), and remains part of the legal social structure of some non-hereditary regimes, e.g., San Marino and the Vatican City in Europe.

Hereditary titles often distinguish nobles from non-nobles, although in many nations most of the nobility have been un- titled, and a hereditary title need not ipso facto indicate nobility (e.g., vidame). Some countries have had non-hereditary nobility, such as the Empire of Brazil.

Oligarchy (from Greek ὀλιγαρχία (oligarkhía); from ὀλίγος (olígos), meaning 'few', and ἄρχω (arkho), meaning 'to rule or to command') is a form of power structure in which power rests with a small number of people. Tese people might be distinguished by nobility, wealth, family ties, education or corporate, religious or military control. Such states are often controlled by families who typically pass their infuence from one generation to the next, but inheritance is not a necessary condition for the application of this term.

Troughout history, oligarchies have often been tyrannical, relying on public obedience or oppression to exist. Aristotle pioneered the use of the term as a synonym for rule by the rich, for which another term commonly used today is plutocracy.

Especially during the fourth century BCE, after the restoration of democracy from oligarchical coups, the Athenians used the drawing of lots for selecting government oﬃcers to counteract what the Athenians saw as a tendency toward oligarchy in government if a professional governing class were allowed to use their skills for their own beneft.[page needed] Tey drew lots from large groups of adult volunteers to pick civil servants performing judicial, executive, and administrative functions (archai, boulē, and hēliastai). Tey even used lots for posts, such as judges and jurors in the political courts (nomothetai), which had the power to overrule the Assembly.

A timocracy (from Greek τιμή timē, "price, worth" and -κρατία -kratia, “rule") is a state where only property owners may participate in government. Te more extreme forms of timocracy, where power derives entirely from wealth with no regard for social or civic responsibility, may shift in their form and become a plutocracy where the wealthy and powerful use their power to increase their wealth.

A tyrant (Greek τύραννος, tyrannos), in the modern English usage of the word, is an absolute ruler unrestrained by law or person, or one who has usurped legitimate sovereignty. Often described as a cruel character, a tyrant defends his position by oppressive means, tending to control almost everything in the state.Te original Greek term, however, merely meant an authoritarian sovereign without reference to character, bearing no pejorative connotation during the Archaic and early Classical periods. However, it was clearly a negative word to Plato, a Greek philosopher, and on account of the decisive infuence of philosophy on politics, its negative connotations only increased, continuing into the Hellenistic period.

Plato and Aristotle defne a tyrant as a person who rules without law, using extreme and cruel methods against both his own people and others. It is defned further in the Encyclopédie as a usurper of sovereign power who makes his subjects the victims of his passions and unjust desires, which he substitutes for laws. During the seventh and sixth centuries BC, tyranny was often looked upon as an intermediate stage between narrow oligarchy and more democratic forms of polity. However, in the late ffth and fourth centuries BC, a new kind of tyrant, the military dictator, arose, specifcally in Sicily.

Tyranny includes a variety of oppressive types of government – by a tyrant (autocracy), by a minority (oligarchy, tyranny of the minority) or by a majority (democracy, tyranny of the majority). Te defnition is extended to other oppressive leadership and to oppressive policies. For example, a teacher may fnd the school administration, the textbook or standardized tests to be oppressive, considering each to represent a tyranny.

Totalitarianism is a political concept where the state recognizes no limits to its authority and strives to regulate every aspect of public and private life wherever feasible. Totalitarian regimes stay in political power through rule by one leader and an all- encompassing propaganda campaign, which is disseminated through the state-controlled mass media, a single party that is often marked by political repression, personality cultism, control over the economy, regulation and restriction of speech, mass surveillance, and widespread use of terror. A distinctive feature of totalitarian governments is an "elaborate ideology, a set of ideas that gives meaning and direction to the whole society."

Te concept was frst developed in the 1920s by the Weimar German jurist, and later Nazi academic, Carl Schmitt, and Italian fascists. According to Benito Mussolini, this system politicizes everything spiritual and human: "Everything within the state, nothing outside the state, nothing against the state." Schmitt used the term, Totalstaat, in his infuential work on the legal basis of an all-powerful state, Te Concept of the Political (1927).

298 Totalitarian regimes are diﬀerent from authoritarian ones. Te latter denotes a state in which the single power holder – an individual "dictator", a committee or a junta or an otherwise small group of political elite – monopolizes political power. "[Te] authoritarian state ... is only concerned with political power and as long as that is not contested it gives society a certain degree of liberty."[4] Authoritarianism "does not attempt to change the world and human nature." In contrast, a totalitarian regime attempts to control virtually all aspects of the social life, including the economy, education, art, science, private life, and morals of citizens. "Te oﬃcially proclaimed ideology penetrates into the deepest reaches of societal structure and the totalitarian government seeks to completely control the thoughts and actions of its citizens." It also mobilizes the whole population in pursuit of its goals. Carl Joachim Friedrich writes that "a totalist ideology, a party reinforced by a secret police, and monopoly control of [...] industrial mass society" are the three features of totalitarian regimes that distinguish them from other autocracies.

Authoritarianism is a form of government characterized by strong central power and limited political freedoms. Individual freedoms are subordinate to the state and there is no constitutional accountability under an authoritarian regime. Juan Linz's infuential 1964 description of authoritarianism characterized authoritarian political systems by four qualities: Limited political pluralism, that is such regimes place constraints on political institutions and groups like legislatures, political parties and interest groups; A basis for legitimacy based on emotion, especially the identifcation of the regime as a necessary evil to combat "easily recognizable societal problems" such as underdevelopment or insurgency; Minimal social mobilization most often caused by constraints on the public such as suppression of political opponents and anti-regime activity; Informally defned executive power with often vague and shifting powers. Modern democratic elective dictatorships use an authoritarian concept to form a government.

Anarchism is a political philosophy that advocates self-governed societies based on voluntary institutions. Tese are often described as stateless societies, although several authors have defned them more specifcally as institutions based on non- hierarchical or free associations. Anarchism holds the state to be undesirable, unnecessary, and harmful.

While opposition to the state is central, anarchism specifcally entails opposing authority or hierarchical organisation in the conduct of all human relations. Anarchism is usually considered a far-left ideology and much of anarchist economics and anarchist legal philosophy refects anti-authoritarian interpretations of communism, collectivism, syndicalism, mutualism or participatory economics.

Anarchism does not oﬀer a fxed body of doctrine from a single particular world view, instead fuxing and fowing as a philosophy. Many types and traditions of anarchism exist, not all of which are mutually exclusive. Anarchist schools of thought can diﬀer fundamentally, supporting anything from extreme individualism to complete collectivism. Strains of anarchism have often been divided into the categories of social and individualist anarchism or similar dual classifcations.

In political science, statism is the belief that the state should control either economic or social policy, or both, to some degree. While the term statism has been in use since the 1850s, it gained signifcant usage in American political discourse throughout the 1930s and 1940s. Ayn Rand made frequent use of it in a series of articles in 1962.

Tribalism is the state of being organized in or an advocate for a tribe or tribes. In terms of conformity, tribalism may also refer in popular cultural terms to a way of thinking or behaving in which people are loyal to their own tribe or social group.

Tribalism has been defned as a 'way of being' based upon variable combinations of kinship-based organization, reciprocal exchange, manual production, oral communication and analogical enquiry. Ontologically, tribalism is oriented around the valences of analogy, genealogy and mythology. Tat means that customary tribes have their social foundations in some variation of these tribal orientations, while often taking on traditional practices (e.g. Abrahamic religions such as Christianity, Judaism, and Islam), and modern practices, including monetary exchange, mobile communications, and modern education.

Te social structure of a tribe can vary greatly from case to case, but the relatively small size of customary tribes makes social life in such of tribes usually involve a relatively undiﬀerentiated role structure, with few signifcant political or economic distinctions between individuals.

Tribalism implies the possession of a strong cultural or ethnic identity that separates one member of a group from the members of another group. Based on strong relations of proximity and kinship, members of a tribe tend to possess a strong feeling of identity. Objectively, for a customary tribal society to form there needs to be ongoing customary organization, enquiry and exchange. However, intense feelings of common identity can lead people to feel tribally connected.

Te distinction between these two defnitions for tribalism, objective and subjective, is an important one because while tribal societies have been pushed to the edges of the Western world, tribalism, by the second defnition, is arguably undiminished.

299 A few writers have postulated that the human brain is hard-wired towards tribalism by its evolutionary advantages, but that claim is usually linked to equating original questions of sociality with tribalism.

A tribe often refers to itself using its own language's word for "people", and refers to other, neighboring tribes with various epithets. For example, the term "Inuit" translates to "people", yet the Inuit were known to the Ojibwe by the name "Eskimo", which translates roughly to "eaters of raw meat".

A revolution (from the Latin revolutio, "a turn around") is a fundamental change in political power or organizational structures that takes place in a relatively short period of time when the population rises up in revolt against the current authorities. Aristotle described two types of political revolution:

Revolutions have occurred through human history and vary widely in terms of methods, duration, and motivating ideology. Teir results include major changes in culture, economy, and socio-political institutions, usually in response to overwhelming autocracy or plutocracy.

Scholarly debates about what does and does not constitute a revolution center on several issues. Early studies of revolutions primarily analyzed events in European history from a psychological perspective, but more modern examinations include global events and incorporate perspectives from several social sciences, including sociology and political science. Several generations of scholarly thought on revolutions have generated many competing theories and contributed much to the current understanding of this complex phenomenon.

A revolutionary is a person who either participates in, or advocates revolution. Also, when used as an adjective, the term revolutionary refers to something that has a major, sudden impact on society or on some aspect of human endeavor. Remember the art of the rebel is using god’s laws too change the law of a land toward revolution.

Futures studies (also called futurology) is the study of postulating possible, probable, and preferable futures and the worldviews and myths that underlie them. Tere is a debate as to whether this discipline is an art or science. In general, it can be considered as a branch of the social sciences and parallel to the feld of history. History studies the past, futures studies considers the future. Futures studies (colloquially called "futures" by many of the feld's practitioners) seeks to understand what is likely to continue and what could plausibly change. Part of the discipline thus seeks a systematic and pattern-based understanding of past and present, and to determine the likelihood of future events and trends. Unlike the physical sciences where a narrower, more specifed system is studied, futures studies concerns a much bigger and more complex world system. Te methodology and knowledge are much less proven as compared to natural science or even social science like sociology, economics, and political science.

Economics (UK English: /iːkəˈnɒmɪks/, /ɛkəˈnɒmɪks/;[1] US English: /ɛkəˈnɑːmɪks/, /ikəˈnɑːmɪks/) is the social science that studies the production, distribution, and consumption of goods and services.

Economics focuses on the behaviour and interactions of economic agents and how economies work. Microeconomics analyzes basic elements in the economy, including individual agents and markets, their interactions, and the outcomes of interactions. Individual agents may include, for example, households, frms, buyers, and sellers. Macroeconomics analyzes the entire economy (meaning aggregated production, consumption, savings, and investment) and issues aﬀecting it, including unemployment of resources (labour, capital, and land), infation, economic growth, and the public policies that address these issues (monetary, fscal, and other policies). See glossary of economics.

Other broad distinctions within economics include those between positive economics, describing "what is", and normative economics, advocating "what ought to be"; between economic theory and applied economics; between rational and behavioural economics; and between mainstream economics and heterodox economics.

Finance is a feld that deals with the study of investments. It includes the dynamics of assets and liabilities over time under conditions of diﬀerent degrees of uncertainty and risk. Finance can also be defned as the science of money management. Finance aims to price assets based on their risk level and their expected rate of return. Finance can be broken into three subcategories: public fnance, corporate fnance and personal fnance.

Capitalism is also an economic system and ideology based upon a carrot being worth 0.00000000001p for seed, 2p from the farmer grown, 5p in a shop, 40p to a chef and 10p out of a £1 curry, even then the excrament has 40% of the nutrients to go back to the soil 0.00000000000000000001p, combined with urine this creates silage, an economy in itself. Characteristics central to capitalism include private property, capital accumulation, wage labor, voluntary exchange, a price system and competitive markets. In a capitalist market economy, decision-making and investment are determined by every owner of 300 wealth, property or production ability in fnancial and capital markets, whereas prices and the distribution of goods and services are mainly determined by competition in goods and services markets.

Economists, political economists, sociologists, and historians have adopted different perspectives in their analyses of capitalism and have recognized various forms of it in practice. Tese include laissez-faire or free market capitalism, welfare capitalism and state capitalism. Different forms of capitalism feature varying degrees of free markets, public ownership,obstacles to free competition and state-sanctioned social policies. Te degree of competition in markets, the role of intervention and regulation and the scope of state ownership vary across different models of capitalism. Te extent to which different markets are free, as well as the rules defning private property, are matters of politics and policy. Most existing capitalist economies are mixed economies, which combine elements of free markets with state intervention and in some cases economic planning.

Market economies have existed under many forms of government, in many diﬀerent times, places and cultures. However, the development of capitalist societies marked by a universalization of money-based social relations, a consistently large and system-wide class of workers who must work for wages and a capitalist class which dominates control of wealth and political power developed in Western Europe in a process that led to the Industrial Revolution. Capitalist systems with varying degrees of direct government intervention have since become dominant in the Western world and continue to spread.

Capitalism has been criticized for establishing power in the hands of a minority capitalist class that exists through the exploitation of a working class majority; for prioritizing proft over social good, natural resources and the environment; and for being an engine of inequality and economic instabilities.[citation needed] Supporters argue that it provides better products through competition, creates strong economic growth, yields productivity and prosperity that greatly benefts society, as well as being the most eﬃcient system known for allocation of resources.

Wealth is the abundance of valuable resources or valuable material possessions. Tis includes the core meaning as held in the originating old English word weal, which is from an Indo-European word stem. An individual, community, region or country that possesses an abundance of such possessions or resources to the beneft of the common good is known as wealthy.

Te modern concept of wealth is of signifcance in all areas of economics, and clearly so for growth economics and development economics yet the meaning of wealth is context-dependent. At the most general level, economists may defne wealth as "anything of value" that captures both the subjective nature of the idea and the idea that it is not a fxed or static concept. Various defnitions and concepts of wealth have been asserted by various individuals and in diﬀerent contexts.Defning wealth can be a normative process with various ethical implications, since often wealth maximization is seen as a goal or is thought to be a normative principle of its own.

Poverty is the scarcity or the lack of a certain (variant) amount of material possessions or money. Poverty is a multifaceted concept, which may include social, economic, and political elements. Absolute poverty, extreme poverty, or destitution refers to the complete lack of the means necessary to meet basic personal needs such as food, clothing and shelter.

Te threshold at which absolute poverty is defned is considered to be about the same, independent of the person's permanent location or era. On the other hand, relative poverty occurs when a person who lives in a given country does not enjoy a certain minimum level of "living standards" as compared to the rest of the population of that country. Terefore, the threshold at which relative poverty is defned varies from country to another, or from one society to another.

Providing basic needs can be restricted by constraints on government's ability to deliver services, such as corruption, tax avoidance, debt and loan conditionalities and by the brain drain of health care and educational professionals. Strategies of increasing income to make basic needs more aﬀordable typically include welfare, economic freedoms and providing fnancial services.[3]

Te Zeitgeist (/ˈzaɪtɡaɪst/; spirit of the age or spirit of the time) is the dominant set of ideals and beliefs that motivate the actions of the members of a society in a particular period in time. For example, the Zeitgeist of modernism motivated the creation of new forms in the felds of architecture, art, and fashion during much of the 20th century. Zeitgeist is a powerful force embedded in the individuals of a society. Te German word Zeitgeist, translated literally as "time mind" or "time spirit", is often attributed to the philosopher Georg Hegel, but he never actually used the word. In his works such as Lectures on the Philosophy of History, he uses the phrase der Geist seiner Zeit (the spirit of his time)—for example, "no man can surpass his own time, for the spirit of his time is also his own spirit."

301 Other philosophers who were associated with such ideas include Herder and Spencer and Voltaire. Te concept contrasts with the Great Man theory popularized by Tomas Carlyle, which sees history as the result of the actions of heroes and geniuses.

Hegel believed that art refected, by its very nature, the culture of the time in which it is created. Culture and art are inextricable because an individual artist is a product of his or her time and therefore brings that culture to any given work of art. Furthermore, he believed that in the modern world it was impossible to produce classical art, which he believed represented a "free and ethical culture", which depended more on the philosophy of art and theory of art, rather than a refection of the social construct, or Zeitgeist in which a given artist lives.

Indigenous peoples, also known as frst peoples, aboriginal peoples or native peoples, are ethnic groups who are the original inhabitants of a given region, in contrast to groups that have settled, occupied or colonized the area more recently. Groups are usually described as indigenous when they maintain traditions or other aspects of an early culture that is associated with a given region. Not all indigenous peoples share this characteristic, sometimes having adopted substantial elements of a colonising culture, such as dress, religion or language. Indigenous peoples may be settled in a given region (sedentary) or exhibit a nomadic lifestyle across a large territory, but they are generally historically associated with a specifc territory on which they depend. Indigenous societies are found in every inhabited climate zone and continent of the world.

A heterarchy is a system of organization where the elements of the organization are unranked (non-hierarchical) or where they possess the potential to be ranked a number of diﬀerent ways.[1] Defnitions of the term vary among the disciplines: in social and information sciences, heterarchies are networks of elements in which each element shares the same "horizontal" position of power and authority, each playing a theoretically equal role. But in biological taxonomy, the requisite features of heterarchy involve, for example, a species sharing, with a species in a diﬀerent family, a common ancestor which it does not share with members of its own family. Tis is theoretically possible under principles of "horizontal gene transfer."

A heterarchy may be parallel to a hierarchy, subsumed to a hierarchy, or it may contain hierarchies; the two kinds of structure are not mutually exclusive. In fact, each level in a hierarchical system is composed of a potentially heterarchical group which contains its constituent elements.

Te concept of heterarchy was frst employed in a modern context by Warren McCulloch in 1945.As Carole L. Crumley has summarised, "[h]e examined alternative cognitive structure(s), the collective organization of which he termed heterarchy. He demonstrated that the human brain, while reasonably orderly was not organized hierarchically. Tis understanding revolutionized the neural study of the brain and solved major problems in the felds of artifcial intelligence and computer design.”

A hierarchy (from the Greek hierarchia, "rule of a high priest", from hierarkhes, "leader of sacred rites") is an arrangement of items (objects, names, values, categories, etc.) in which the items are represented as being "above", "below", or "at the same level as" one another.

A hierarchy can link entities either directly or indirectly, and either vertically or diagonally. Te only direct links in a hierarchy, insofar as they are hierarchical, are to one's immediate superior or to one of one's subordinates, although a system that is largely hierarchical can also incorporate alternative hierarchies. Indirect hierarchical links can extend "vertically" upwards or downwards via multiple links in the same direction, following a path. All parts of the hierarchy which are not linked vertically to one another nevertheless can be "horizontally" linked through a path by traveling up the hierarchy to fnd a common direct or indirect superior, and then down again. Tis is akin to two co-workers or colleagues; each reports to a common superior, but they have the same relative amount of authority. Organizational forms exist that are both alternative and complementary to hierarchy. Heterarchy is one such form.

An entity is something that exists as itself, as a subject or as an object, actually or potentially, concretely or abstractly, physically or not. It need not be of material existence. In particular, abstractions and legal fctions are usually regarded as entities. In general, there is also no presumption that an entity is animate, or present.

Te word is abstract in intention. It may refer, for example, to Bucephalus, the horse of Alexander; to a stone; to a cardinal number; to a language; or to ghosts or other spirits.

Te word entitative is the adjective form of the noun entity. Something that is entitative is considered in its own right.

Ethnography (from Greek ἔθνος ethnos "folk, people, nation" and γράφω grapho "I write") is the systematic study of people and cultures. It is designed to explore cultural phenomena where the researcher observes society from the point of view of the subject of the study. An ethnography is a means to represent graphically and in writing the culture of a group. 302 Te word can thus be said to have a double meaning, which partly depends on whether it is used as a count noun or uncountable. Te resulting feld study or a case report refects the knowledge and the system of meanings in the lives of a cultural group.

Ethnography, as the presentation of empirical data on human societies and cultures, was pioneered in the biological, social, and cultural branches of anthropology, but it has also become popular in the social sciences in general—sociology, communication studies, history—wherever people study ethnic groups, formations, compositions, resettlements, social welfare characteristics, materiality, spirituality, and a people's ethnogenesis. Te typical ethnography is a holistic study and so includes a brief history, and an analysis of the terrain, the climate, and the habitat. In all cases, it should be refexive, make a substantial contribution toward the understanding of the social life of humans, have an aesthetic impact on the reader, and express a credible reality. An ethnography records all observed behavior and describes all symbol-meaning relations, using concepts that avoid causal explanations.

A social class is a set of subjectively defned concepts in the social sciences and political theory centered on models of social stratifcation in which people are grouped into a set of hierarchical social categories, the most common being the upper, middle and lower classes.

"Class" is a subject of analysis for sociologists, political scientists, anthropologists and social historians. However, there is not a consensus on a defnition of "class" and the term has a wide range of sometimes conficting meanings. In common parlance, the term "social class" is usually synonymous with "socio-economic class", defned as "people having the same social, economic, cultural, political or educational status", e.g., "the working class"; "an emerging professional class". However, academics distinguish social class and socioeconomic status, with the former referring to one's relatively stable sociocultural background and the latter referring to one's current social and economic situation and consequently being more changeable over time.[3]

Te precise measurements of what determines social class in society has varied over time. Karl Marx thought "class" was defned by one's relationship to the means of production (their relations of production). His simple understanding of classes in modern capitalist society are the proletariat, those who work but do not own the means of production; and the bourgeoisie, those who invest and live oﬀ of the surplus generated by the proletariat's operation of the means of production. Tis contrasts with the view of the sociologist Max Weber, who argued "class" is determined by economic position, in contrast to "social status" or "Stand" which is determined by social prestige rather than simply just relations of production. Te term "class" is etymologically derived from the Latin classis, which was used by census takers to categorize citizens by wealth in order to determine military service obligations.

In the late 18th century, the term "class" began to replace classifcations such as estates, rank and orders as the primary means of organizing society into hierarchical divisions. Tis corresponded to a general decrease in signifcance ascribed to hereditary characteristics and increase in the signifcance of wealth and income as indicators of position in the social hierarchy.

Te upper class in modern societies is the social class composed of the wealthiest members of society, who also wield the greatest political power. According to this view, the upper class is generally distinguished by immense wealth which is passed on from generation to generation. Prior to the 20th century, the nomenclature aristocracy was widely used.

Because the upper classes of a society may no longer rule the society in which they are living, they are often referred to as the old upper classes and they are often culturally distinct from the newly rich middle classes that tend to dominate public life in modern social democracies.[citation needed] According to the latter view held by the traditional upper classes, no amount of individual wealth or fame would make a person from an undistinguished background into a member of the upper class as one must be born into a family of that class and raised in a particular manner so as to understand and share upper class values, traditions, and cultural norms. Te term is often used in conjunction with terms like "upper-middle class", "middle class", and "working class" as part of a model of social stratifcation.

Te middle class is a class of people in the middle of a social hierarchy. In Weberian socio-economic terms, the middle class is the broad group of people in contemporary society who fall socio-economically between the working class and upper class. Te common measures of what constitutes middle class vary signifcantly among cultures. A sizable and healthy middle-class can be viewed as a characteristic of a healthy society.

Te working class (also labouring class and proletariat) are the people employed for wages, especially in manual-labour occupations and industrial work. Working-class occupations include blue-collar jobs, some white-collar jobs, and most pink- collar jobs. Te working class only rely upon their earnings from wage labour, thereby, the category includes most of the

303 working population of industrialized economies, of the urban areas (cities, towns, villages) of non-industrialized economies, and of the rural workforce.

Te pure class, those who adobe by religion and its laws and especially who see everyone as equal.

In Marxist theory and socialist literature, the term working class is often used interchangeably with the term proletariat, and includes all workers who expend both physical and mental labour (salaried knowledge workers and white-collar workers) to produce economic value for the owners of the means of production (the bourgeoisie in Marxist literature).

Te bourgeoisie (/ˌbʊərʒwɑːˈziː/; French: [buʁʒwazi]) is a polysemous French term that can mean: originally and generally, "those who live in the borough", that is to say, the people of the city (including merchants and craftsmen), as opposed to those of rural areas; in this sense, the bourgeoisie began to grow in Europe from the 11th century and particularly during the Renaissance of the 12th century, with the frst developments of rural exodus and urbanization.

A legally defned class of the Middle Ages to the end of the Ancient Régime (Old Regime) in France, that of inhabitants having the rights of citizenship and political rights in a city (comparable to the German term Bürgertum and Bürger; see also "Burgher"). Tis bourgeoisie destroyed aristocratic privilege and established civic equality after the French monarchy collapsed. Te aristocracy crumbled because it refused to reform institutions and fnancial systems.

A sociologically defned class, especially in contemporary times, referring to people with a certain cultural and fnancial capital belonging to the middle or upper stratum of the middle class: the upper (haute), middle (moyenne), and petty (petite) bourgeoisie (which are collectively designated "the Bourgeoisie"); an aﬄuent and often opulent stratum of the middle class (capitalist class) who stand opposite the proletariat class. Te "Bourgeoisie", in its original sense, is intimately linked to the existence of cities recognized as such by their urban charters (e.g. municipal charter, town privileges, German town law) so there was no bourgeoisie "outside the walls of the city" beyond which the people were "peasants" submitted to the stately courts and manorialism (except for the traveling "Fair bourgeoisie" living outside urban territories, who retained their city rights and domicile).

In Marxist philosophy the bourgeoisie is the social class that came to own the means of production during modern industrialization and whose societal concerns are the value of property and the preservation of capital, to ensure the perpetuation of their economic supremacy in society. Joseph Schumpeter saw the creation of new bourgeoisie as the driving force behind the capitalist engine, particularly entrepreneurs who took risks to bring innovation to industries and the economy through the process of creative destruction.

A civilization (UK and US) or civilisation (UK variant) is any complex society characterized by urban development, social stratifcation imposed by a cultural elite, symbolic systems of communication (for example, writing systems), and a perceived separation from and domination over the natural environment.

Civilizations are intimately associated with and often further defned by other socio-politico-economic characteristics, including centralization, the domestication of both humans and other organisms, specialization of labour, culturally ingrained ideologies of progress and supremacism, monumental architecture, taxation, societal dependence upon farming and expansionism.[2][3][4][6][7][8] Historically, a civilization was a so-called "advanced" culture in contrast to more supposedly primitive cultures. In this broad sense, a civilization contrasts with non-centralized tribal societies, including the cultures of nomadic pastoralists, Neolithic societies or hunter-gatherers. As an uncountable noun, civilization also refers to the process of a society developing into a centralized, urbanized, stratifed structure. Civilizations are organized in densely populated settlements divided into hierarchical social classes with a ruling elite and subordinate urban and rural populations, which engage in intensive agriculture, mining, small-scale manufacture and trade. Civilization concentrates power, extending human control over the rest of nature, including over other human beings.

Te earliest emergence of civilizations is generally associated with the fnal stages of the Neolithic Revolution, culminating in the relatively rapid process of urban revolution and state formation, a political development associated with the appearance of a governing elite. Te earlier neolithic technology and lifestyle was established frst in the Middle East (for example at Göbekli Tepe, from about 9,130 BCE), and later in the Yellow River and Yangtze basins in China (for example the Pengtoushan culture from 7,500 BCE), and later spread. Similar pre-civilized "neolithic revolutions" also began independently from 7,000 BCE in such places as northwestern South America (the Norte Chico civilization) and Mesoamerica. Tese were among the fve civilizations worldwide that arose independently.[12] Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BCE, with civilizations developing from 6,500 years ago. Tis area has been identifed as having "inspired some of the most important developments in human history including the invention of the wheel, the development of cursive script, mathematics, astronomy and agriculture."

304 Te civilized urban revolution in turn was dependent upon the development of sedentism, the domestication of grains and animals and development of lifestyles that facilitated economies of scale and accumulation of surplus production by certain social sectors. Te transition from complex cultures to civilizations, while still disputed, seems to be associated with the development of state structures, in which power was further monopolized by an elite ruling class[14] who practised human sacrifce. Towards the end of the Neolithic period, various elitist Chalcolithic civilizations began to rise in various "cradles" from around 3300 BCE. Chalcolithic civilizations, as defned above, also developed in Pre-Columbian Americas and, despite an early start in Egypt, Axum and Kush, much later in Iron Age sub-Saharan Africa. Te Bronze Age collapse was followed by the Iron Age around 1200 BCE, during which a number of new civilizations emerged, culminating in a period from the 8th to the 3rd century BCE which German psychiatrist and philosopher Karl Jaspers termed the Axial Age, and which he claimed was a critical transitional phase leading to classical civilization. A major technological and cultural transition to modernity began approximately 1500 CE in Western Europe, and from this beginning new approaches to science and law spread rapidly around the world, incorporating earlier cultures into the industrial and technological civilization of the present.

Te Banoshie word "civilization" comes from the 16th-century French civilisé ("civilized"), from Latin civilis ("civil"), related to civis ("citizen") and civitas (“city"). Te fundamental treatise is Norbert Elias's Te Civilizing Process (1939), which traces social mores from medieval courtly society to the Early Modern period.[ In Te Philosophy of Civilization (1923), Albert Schweitzer outlines two opinions: one purely material and the other material and ethical. He said that the world crisis was from humanity losing the ethical idea of civilization, "the sum total of all progress made by man in every sphere of action and from every point of view in so far as the progress helps towards the spiritual perfecting of individuals as the progress of all progress".

Adjectives like "civility" developed in the mid-16th century. Te abstract noun "civilization", meaning "civilized condition", came in the 1760s, again from French. Te frst known use in French is in 1757, by Victor Riqueti, marquis de Mirabeau, and the frst use in English is attributed to Adam Ferguson, who in his 1767 Essay on the History of Civil Society wrote, "Not only the individual advances from infancy to manhood, but the species itself from rudeness to civilisation". Te word was therefore opposed to barbarism or rudeness, in the active pursuit of progress characteristic of the Age of Enlightenment.

In the late 1700s and early 1800s, during the French Revolution, "civilization" was used in the singular, never in the plural, and meant the progress of humanity as a whole. Tis is still the case in French. Te use of "civilizations" as a countable noun was in occasional use in the 19th century, but has become much more common in the later 20th century, sometimes just meaning culture (itself in origin an uncountable noun, made countable in the context of ethnography). Only in this generalized sense does it become possible to speak of a "medieval civilization", which in Elias's sense would have been an oxymoron.

Already in the 18th century, civilization was not always seen as an improvement. One historically important distinction between culture and civilization is from the writings of Rousseau, particularly his work about education, Emile. Here, civilization, being more rational and socially driven, is not fully in accord with human nature, and "human wholeness is achievable only through the recovery of or approximation to an original prediscursive or prerational natural unity" (see noble savage). From this, a new approach was developed, especially in Germany, frst by Johann Gottfried Herder, and later by philosophers such as Kierkegaard and Nietzsche. Tis sees cultures as natural organisms, not defned by "conscious, rational, deliberative acts", but a kind of pre-rational "folk spirit". Civilization, in contrast, though more rational and more successful in material progress, is unnatural and leads to "vices of social life" such as guile, hypocrisy, envy and avarice.[20] In World War II, Leo Strauss, having fed Germany, argued in New York that this opinion of civilization was behind Nazism and German militarism and nihilism.

Social scientists such as V. Gordon Childe have named a number of traits that distinguish a civilization from other kinds of society. Civilizations have been distinguished by their means of subsistence, types of livelihood, settlement patterns, forms of government, social stratifcation, economic systems, literacy and other cultural traits. Andrew Nikiforuk argues that "civilizations relied on shackled human muscle. It took the energy of slaves to plant crops, clothe emperors, and build cities" and considers slavery to be a common feature of pre-modern civilizations.

All civilizations have depended on agriculture for subsistence, with the possible exception of some early civilizations in Peru which may have depended upon maritime resources. Grain farms can result in accumulated storage and a surplus of food, particularly when people use intensive agricultural techniques such as artifcial fertilization, irrigation and crop rotation. It is possible but more diﬃcult to accumulate horticultural production, and so civilizations based on horticultural gardening have been very rare.[29] Grain surpluses have been especially important because grain can be stored for a long time. A surplus of food permits some people to do things besides produce food for a living: early civilizations included soldiers, artisans, priests and priestesses, and other people with specialized careers. A surplus of food results in a division of labour and a more diverse range of human activity, a defning trait of civilizations. However, in some places hunter-gatherers have had access to food

305 surpluses, such as among some of the indigenous peoples of the Pacifc Northwest and perhaps during the Mesolithic Natufan culture. It is possible that food surpluses and relatively large scale social organization and division of labour predates plant and animal domestication.

Civilizations have distinctly diﬀerent settlement patterns from other societies. Te word "civilization" is sometimes simply defned as "'living in cities'". Non-farmers tend to gather in cities to work and to trade.

Compared with other societies, civilizations have a more complex political structure, namely the state. State societies are more stratifed than other societies; there is a greater diﬀerence among the social classes. Te ruling class, normally concentrated in the cities, has control over much of the surplus and exercises its will through the actions of a government or bureaucracy. Morton Fried, a confict theorist and Elman Service, an integration theorist, have classifed human cultures based on political systems and social inequality. Tis system of classifcation contains four categories

Hunter-gatherer bands, which are generally egalitarian. Horticultural/pastoral societies in which there are generally two inherited social classes; chief and commoner. Highly stratifed structures, or chiefdoms, with several inherited social classes: king, noble, freemen, serf and slave. Civilizations, with complex social hierarchies and organized, institutional governments. Economically, civilizations display more complex patterns of ownership and exchange than less organized societies. Living in one place allows people to accumulate more personal possessions than nomadic people. Some people also acquire landed property, or private ownership of the land. Because a percentage of people in civilizations do not grow their own food, they must trade their goods and services for food in a market system, or receive food through the levy of tribute, redistributive taxation, tariﬀs or tithes from the food producing segment of the population. Early human cultures functioned through a gift economy supplemented by limited barter systems. By the early Iron Age, contemporary civilizations developed money as a medium of exchange for increasingly complex transactions. In a village, the potter makes a pot for the brewer and the brewer compensates the potter by giving him a certain amount of beer. In a city, the potter may need a new roof, the roofer may need new shoes, the cobbler may need new horseshoes, the blacksmith may need a new coat and the tanner may need a new pot. Tese people may not be personally acquainted with one another and their needs may not occur all at the same time. A monetary system is a way of organizing these obligations to ensure that they are fulflled. From the days of the earliest monetarized civilizations, monopolistic controls of monetary systems have benefted the social and political elites.

Writing, developed frst by people in Sumer, is considered a hallmark of civilization and "appears to accompany the rise of complex administrative bureaucracies or the conquest state". Traders and bureaucrats relied on writing to keep accurate records. Like money, writing was necessitated by the size of the population of a city and the complexity of its commerce among people who are not all personally acquainted with each other. However, writing is not always necessary for civilization, as shown the Inca civilization of the Andes, which did not use writing at all except from a complex recording system consisting of cords and nodes instead: the "Quipus", whose still functioned as a civilized society.

Aided by their division of labour and central government planning, civilizations have developed many other diverse cultural traits. Tese include organized religion, development in the arts, and countless new advances in science and technology.

Trough history, successful civilizations have spread, taking over more and more territory, and assimilating more and more previously-uncivilized people. Nevertheless, some tribes or people remain uncivilized even to this day. Tese cultures are called by some "primitive", a term that is regarded by others as pejorative. "Primitive" implies in some way that a culture is "frst" (Latin = primus), that it has not changed since the dawn of humanity, though this has been demonstrated not to be true. Specifcally, as all of today's cultures are contemporaries, today's so-called primitive cultures are in no way antecedent to those we consider civilized. Anthropologists today use the term "non-literate" to describe these peoples.

Civilization has been spread by colonization, invasion, religious conversion, the extension of bureaucratic control and trade, and by introducing agriculture and writing to non-literate peoples. Some non-civilized people may willingly adapt to civilized behaviour. But civilization is also spread by the technical, material and social dominance that civilization engenders.

Assessments of what level of civilization a polity has reached are based on comparisons of the relative importance of agricultural as opposed to trade or manufacturing capacities, the territorial extensions of its power, the complexity of its division of labour, and the carrying capacity of its urban centres. Secondary elements include a developed transportation system, writing, standardized measurement, currency, contractual and tort-based legal systems, art, architecture, mathematics, scientifc understanding, metallurgy, political structures and organized religion.

Traditionally, polities that managed to achieve notable military, ideological and economic power defned themselves as "civilized" as opposed to other societies or human groupings outside their sphere of infuence—calling the latter barbarians,

306 savages, and primitives. In a modern-day context, "civilized people" have been contrasted with indigenous people or tribal societies.

"Civilization" can also refer to the culture of a complex society, not just the society itself. Every society, civilization or not, has a specifc set of ideas and customs, and a certain set of manufactures and arts that make it unique. Civilizations tend to develop intricate cultures, including a state-based decision making apparatus, a literature, professional art, architecture, organized religion and complex customs of education, coercion and control associated with maintaining the elite.

A world map of major civilizations according to the political hypothesis Clash of Civilizations by Samuel P. Huntington Te intricate culture associated with civilization has a tendency to spread to and infuence other cultures, sometimes assimilating them into the civilization (a classic example being Chinese civilization and its infuence on nearby civilizations such as Korea, Japan and Vietnam). Many civilizations are actually large cultural spheres containing many nations and regions. Te civilization in which someone lives is that person's broadest cultural identity.

Many historians have focused on these broad cultural spheres and have treated civilizations as discrete units. Early twentieth- century philosopher Oswald Spengler, uses the German word Kultur, "culture", for what many call a "civilization". Spengler believes a civilization's coherence is based on a single primary cultural symbol. Cultures experience cycles of birth, life, decline and death, often supplanted by a potent new culture, formed around a compelling new cultural symbol. Spengler states civilization is the beginning of the decline of a culture as "the most external and artifcial states of which a species of developed humanity is capable".

Tis "unifed culture" concept of civilization also infuenced the theories of historian Arnold J. Toynbee in the mid-twentieth century. Toynbee explored civilization processes in his multi-volume A Study of History, which traced the rise and, in most cases, the decline of 21 civilizations and fve "arrested civilizations". Civilizations generally declined and fell, according to Toynbee, because of the failure of a "creative minority", through moral or religious decline, to meet some important challenge, rather than mere economic or environmental causes.

Samuel P. Huntington defnes civilization as "the highest cultural grouping of people and the broadest level of cultural identity people have short of that which distinguishes humans from other species". Huntington's theories about civilizations are discussed below.

Another group of theorists, making use of systems theory, looks at a civilization as a complex system, i.e., a framework by which a group of objects can be analysed that work in concert to produce some result. Civilizations can be seen as networks of cities that emerge from pre-urban cultures and are defned by the economic, political, military, diplomatic, social and cultural interactions among them. Any organization is a complex social system and a civilization is a large organization. Systems theory helps guard against superfcial but misleading analogies in the study and description of civilizations.

Systems theorists look at many types of relations between cities, including economic relations, cultural exchanges and political/diplomatic/military relations. Tese spheres often occur on diﬀerent scales. For example, trade networks were, until the nineteenth century, much larger than either cultural spheres or political spheres. Extensive trade routes, including the Silk Road through Central Asia and Indian Ocean sea routes linking the Roman Empire, Persian Empire, India and China, were well established 2000 years ago, when these civilizations scarcely shared any political, diplomatic, military, or cultural relations. Te frst evidence of such long distance trade is in the ancient world. During the Uruk period, Guillermo Algaze has argued that trade relations connected Egypt, Mesopotamia, Iran and Afghanistan. Resin found later in the Royal Cemetery at Ur is suggested was traded northwards from Mozambique.

Many theorists argue that the entire world has already become integrated into a single "world system", a process known as globalization. Diﬀerent civilizations and societies all over the globe are economically, politically, and even culturally interdependent in many ways. Tere is debate over when this integration began, and what sort of integration – cultural, technological, economic, political, or military-diplomatic – is the key indicator in determining the extent of a civilization. David Wilkinson has proposed that economic and military-diplomatic integration of the Mesopotamian and Egyptian civilizations resulted in the creation of what he calls the "Central Civilization" around 1500 BCE.[41] Central Civilization later expanded to include the entire Middle East and Europe, and then expanded to a global scale with European colonization, integrating the Americas, Australia, China and Japan by the nineteenth century. According to Wilkinson, civilizations can be culturally heterogeneous, like the Central Civilization, or homogeneous, like the Japanese civilization. What Huntington calls the "clash of civilizations" might be characterized by Wilkinson as a clash of cultural spheres within a single global civilization. Others point to the Crusades as the frst step in globalization. Te more conventional viewpoint is that networks of societies have expanded and shrunk since ancient times, and that the current globalized economy and culture is a product of recent European colonialism.

307 In cultural anthropology, sedentism (sometimes called sedentariness; compare sedentarism) is the practice of living in one place for a long time. As of 2018, the majority of people belong to sedentary cultures. In evolutionary anthropology and archaeology, sedentism takes on a slightly diﬀerent sub-meaning, often applying to the transition from nomadic society to a lifestyle that involves remaining in one place permanently. Essentially, sedentism means living in groups permanently in one place.

Te process of sedentism is frst thought to have occurred around 12,000 BCE in the Levant region of southwest Asia though other regions around the world soon followed. Te emergence of civilization is generally associated with the Neolithic, or Agricultural Revolution, which occurred in various locations between 8,000 and 5,000 BCE, specifcally in southwestern/southern Asia, northern/central Africa and Central America. At frst, the Neolithic was associated with shifting subsistence cultivation, where continuous farming led to the depletion of soil fertility resulting in the requirement to cultivate felds further and further removed from the settlement, eventually compelling the settlement itself to move. In major semi-arid river valleys, annual fooding renewed soil fertility every year, with the result that population densities could rise signifcantly. Tis encouraged a secondary products revolution in which people used domesticated animals not just for meat, but also for milk, wool, manure and pulling ploughs and carts—a development that spread through the Eurasian Oecumene. Te 8.2 Kiloyear Arid Event and the 5.9 Kiloyear Interpluvial saw the drying out of semiarid regions and a major spread of deserts. Tis climate change shifted the cost-beneft ratio of endemic violence between communities, which saw the abandonment of unwalled village communities and the appearance of walled cities, associated with the frst civilizations. Tis "urban revolution" marked the beginning of the accumulation of transferrable surpluses, which helped economies and cities develop. It was associated with the state monopoly of violence, the appearance of a soldier class and endemic warfare, rapid development of hierarchies, the appearance of human sacrifce.

Political scientist Samuel Huntington has argued that the defning characteristic of the 21st century will be a clash of civilizations. According to Huntington, conficts between civilizations will supplant the conficts between nation-states and ideologies that characterized the 19th and 20th centuries. Tese views have been strongly challenged by others like Edward Said, Muhammed Asadi and Amartya Sen.[60] Ronald Inglehart and Pippa Norris have argued that the "true clash of civilizations" between the Muslim world and the West is caused by the Muslim rejection of the West's more liberal sexual values, rather than a diﬀerence in political ideology, although they note that this lack of tolerance is likely to lead to an eventual rejection of (true) democracy. In Identity and Violence Sen questions if people should be divided along the lines of a supposed "civilization", defned by religion and culture only. He argues that this ignores the many others identities that make up people and leads to a focus on diﬀerences.

Cultural Historian Morris Berman suggests in Dark Ages America: the End of Empire that in the corporate consumerist United States, the very factors that once propelled it to greatness―extreme individualism, territorial and economic expansion, and the pursuit of material wealth―have pushed the United States across a critical threshold where collapse is inevitable. Politically associated with over-reach, and as a result of the environmental exhaustion and polarization of wealth between rich and poor, he concludes the current system is fast arriving at a situation where continuation of the existing system saddled with huge defcits and a hollowed-out economy is physically, socially, economically and politically impossible. Although developed in much more depth, Berman's thesis is similar in some ways to that of Urban Planner, Jane Jacobs who argues that fve pillars of United States culture that are in serious decay: community and family; higher education; the eﬀective practice of science; taxation and government; and the self-regulation of the learned professions. Te corrosion of these pillars, Jacobs argues, is linked to societal ills such as environmental crisis, racism and the growing gulf between rich and poor.

Some environmental scientists also see the world entering a Planetary Phase of Civilization, characterized by a shift away from independent, disconnected nation-states to a world of increased global connectivity with worldwide institutions, environmental challenges, economic systems, and consciousness. In an attempt to better understand what a Planetary Phase of Civilization might look like in the current context of declining natural resources and increasing consumption, the Global scenario group used scenario analysis to arrive at three archetypal futures: Barbarization, in which increasing conficts result in either a fortress world or complete societal breakdown; Conventional Worlds, in which market forces or Policy reform slowly precipitate more sustainable practices; and a Great Transition, in which either the sum of fragmented Eco- Communalism movements add up to a sustainable world or globally coordinated eﬀorts and initiatives result in a new sustainability paradigm.

Te Kardashev scale classifes civilizations based on their level of technological advancement, specifcally measured by the amount of energy a civilization is able to harness. Te Kardashev scale makes provisions for civilizations far more technologically advanced than any currently known to exist (see also: Civilizations and the Future and Space civilization).

308 Humanities are academic disciplines that study aspects of human society and culture. In the renaissance, the term contrasted with divinity and referred to what is now called classics, the main area of secular study in universities at the time. Today, the humanities are more frequently contrasted with natural, and sometimes social, sciences as well as professional training.

Te humanities use methods that are primarily critical, or speculative, and have a signifcant historical element—as distinguished from the mainly empirical approaches of the natural sciences, yet, unlike the sciences, it has no central discipline. Te humanities include ancient and modern languages, literature, philosophy, geography, history, religion, art and musicology.

Scholars in the humanities are "humanity scholars" or humanists. Te term "humanist" also describes the philosophical position of humanism, which some "antihumanist" scholars in the humanities refuse. Te Renaissance scholars and artists were also called humanists. Some secondary schools oﬀer humanities classes usually consisting of English literature, global studies and art.

Human disciplines like history and cultural anthropology study subject matters that the manipulative experimental method does not apply to—and instead mainly use the comparative method and comparative research.

Anthropology is the holistic "science of humans", a science of the totality of human existence. Te discipline deals with the integration of diﬀerent aspects of the social sciences, humanities and human biology. In the twentieth century, academic disciplines have often been institutionally divided into three broad domains. Te natural sciences seek to derive general laws through reproducible and verifable experiments. Te humanities generally study local traditions, through their history, literature, music, and arts, with an emphasis on understanding particular individuals, events, or eras. Te social sciences have generally attempted to develop scientifc methods to understand social phenomena in a generalizable way, though usually with methods distinct from those of the natural sciences.

Te anthropological social sciences often develop nuanced descriptions rather than the general laws derived in physics or chemistry, or they may explain individual cases through more general principles, as in many felds of psychology. Anthropology (like some felds of history) does not easily ft into one of these categories, and diﬀerent branches of anthropology draw on one or more of these domains.[7] Within the United States, anthropology is divided into four sub- felds: archaeology, physical or biological anthropology, anthropological linguistics, and cultural anthropology. It is an area that is oﬀered at most undergraduate institutions. Te word anthropos (άνθρωπος) is from the Greek for "human being" or "person". Eric Wolf described sociocultural anthropology as "the most scientifc of the humanities, and the most humanistic of the sciences".

Te goal of anthropology is to provide a holistic account of humans and human nature. Tis means that, though anthropologists generally specialize in only one sub-feld, they always keep in mind the biological, linguistic, historic and cultural aspects of any problem. Since anthropology arose as a science in Western societies that were complex and industrial, a major trend within anthropology has been a methodological drive to study peoples in societies with more simple social organization, sometimes called "primitive" in anthropological literature, but without any connotation of "inferior". Today, anthropologists use terms such as "less complex" societies or refer to specifc modes of subsistence or production, such as "pastoralist" or "forager" or "horticulturalist" to refer to humans living in non-industrial, non-Western cultures, such people or folk (ethnos) remaining of great interest within anthropology.

Te quest for holism leads most anthropologists to study a people in detail, using biogenetic, archaeological, and linguistic data alongside direct observation of contemporary customs.[9] In the 1990s and 2000s, calls for clarifcation of what constitutes a culture, of how an observer knows where his or her own culture ends and another begins, and other crucial topics in writing anthropology were heard. It is possible to view all human cultures as part of one large, evolving global culture. Tese dynamic relationships, between what can be observed on the ground, as opposed to what can be observed by compiling many local observations remain fundamental in any kind of anthropology, whether cultural, biological, linguistic or archaeological.

Education;

Education is the process of facilitating learning, or the acquisition of knowledge, skills, values, beliefs, and habits. Educational methods include teaching, training, storytelling, discussion and directed research. Education frequently takes place under the guidance of educators, however learners can also educate themselves.[1] Education can take place in formal or informal settings and any experience that has a formative eﬀect on the way one thinks, feels, or acts may be considered educational. Te methodology of teaching is called pedagogy. Formal education is commonly divided formally into such stages as preschool or kindergarten, primary school, secondary school and then college, university, or apprenticeship. 309 A right to education has been recognized by some governments and the United Nations.[2] In most regions, education is compulsory up to a certain age. Tere is a movement for education reform, and in particular for evidence-based education.

Etymologically, the word "education" is derived from the Latin word ēducātiō ("A breeding, a bringing up, a rearing") from ēducō ("I educate, I train") which is related to the homonym ēdūcō ("I lead forth, I take out; I raise up, I erect") from ē- ("from, out of") and dūcō ("I lead, I conduct”).[3]

Matteo Ricci (left) and Xu Guangqi (right) in the Chinese edition of Euclid's Elements published in 1607 Plato founded the Academy in Athens, the frst institution of higher learning in Europe.[5] Te city of Alexandria in Egypt, established in 330 BCE, became the successor to Athens as the intellectual cradle of Ancient Greece. Tere, the great Library of Alexandria was built in the 3rd century BCE. European civilizations suﬀered a collapse of literacy and organization following the fall of Rome in CE 476.[6] In China, Confucius (551–479 BCE), of the State of Lu, was the country's most infuential ancient philosopher, whose educational outlook continues to infuence the societies of China and neighbours like Korea, Japan, and Vietnam. Confucius gathered disciples and searched in vain for a ruler who would adopt his ideals for good governance, but his Analects were written down by followers and have continued to infuence education in East Asia into the modern era.[7] Te Aztecs also had a well-developed theory about education, which has an equivalent word in Nahuatl called tlacahuapahualiztli. It means "the art of raising or educating a person"[8] or "the art of strengthening or bringing up men."[9] Tis was a broad conceptualization of education, which prescribed that it begins at home, supported by formal schooling, and reinforced by community living. Historians cite that formal education was mandatory for everyone regardless of social class and gender.[10] Tere was also the word neixtlamachiliztli, which is "the act of giving wisdom to the face."[9] Tese concepts underscore a complex set of educational practices, which was oriented towards communicating to the next generation the experience and intellectual heritage of the past for the purpose of individual development and his integration into the community.[9] After the Fall of Rome, the Catholic Church became the sole preserver of literate scholarship in Western Europe.[11] Te church established cathedral schools in the Early Middle Ages as centres of advanced education. Some of these establishments ultimately evolved into medieval universities and forebears of many of Europe's modern universities.[6] During the High Middle Ages, Chartres Cathedral operated the famous and infuential Chartres Cathedral School. Te medieval universities of Western Christendom were well-integrated across all of Western Europe, encouraged freedom of inquiry, and produced a great variety of fne scholars and natural philosophers, including Tomas Aquinas of the University of Naples, Robert Grosseteste of the University of Oxford, an early expositor of a systematic method of scientifc experimentation,[12] and Saint Albert the Great, a pioneer of biological feld research.[13] Founded in 1088, the University of Bologne is considered the frst, and the oldest continually operating university.[14] Elsewhere during the Middle Ages, Islamic science and mathematics fourished under the Islamic caliphate which was established across the Middle East, extending from the Iberian Peninsula in the west to the Indus in the east and to the Almoravid Dynasty and Mali Empire in the south. Te Renaissance in Europe ushered in a new age of scientifc and intellectual inquiry and appreciation of ancient Greek and Roman civilizations. Around 1450, Johannes Gutenberg developed a printing press, which allowed works of literature to spread more quickly. Te European Age of Empires saw European ideas of education in philosophy, religion, arts and sciences spread out across the globe. Missionaries and scholars also brought back new ideas from other civilizations – as with the Jesuit China missions who played a signifcant role in the transmission of knowledge, science, and culture between China and Europe, translating works from Europe like Euclid's Elements for Chinese scholars and the thoughts of Confucius for European audiences. Te Enlightenment saw the emergence of a more secular educational outlook in Europe. In most countries today, full-time education, whether at school or otherwise, is compulsory for all children up to a certain age. Due to this the proliferation of compulsory education, combined with population growth, UNESCO has calculated that in the next 30 years more people will receive formal education than in all of human history thus far.[15] Formal education Formal education occurs in a structured environment whose explicit purpose is teaching students. Usually, formal education takes place in a school environment with classrooms of multiple students learning together with a trained, certifed teacher of the subject. Most school systems are designed around a set of values or ideals that govern all educational choices in that system. Such choices include curriculum, organizational models, design of the physical learning spaces (e.g. classrooms), student-teacher interactions, methods of assessment, class size, educational activities, and more.[16][17] Te International Standard Classifcation of Education (ISCED) was created by UNESCO as a statistical base to compare education systems.[18]In 1997, it defned 7 levels of education and 25 felds, though the felds were later separated out to

310 form a diﬀerent project. Te current version ISCED 2011 has 9 rather than 7 levels, created by dividing the tertiary pre- doctorate level into three levels. It also extended the lowest level (ISCED 0) to cover a new sub-category of early childhood educational development programmes, which target children below the age of 3 years.[19] Early childhood education Main article: Early childhood education

Education designed to support early development in preparation for participation in school and society. Te programmes are designed for children below the age of 3. Tis is ISCED level 01. [18] Preschools provide education from ages approximately three to seven, depending on the country when children enter primary education. Te children now readily interact with their peers and the educator.[18] Tese are also known as nursery schools and as kindergarten, except in the US, where the term kindergarten refers to the earliest levels of primary education.[20] Kindergarten "provide[s] a child-centred, preschool curriculum for three- to seven-year-old children that aim[s] at unfolding the child's physical, intellectual, and moral nature with balanced emphasis on each of them."[21] Tis is ISCED level 02. [18] Primary Main article: Primary education Tis is ISCED level 1. [18] Primary (or elementary) education consists of the frst four to seven years of formal, structured education. Tey are typically designed to provide young children with functional literacy and numeracy skills and to is guaranteed, solid foundation for most areas of knowledge and personal and social development to support the transition to secondary school.[22] In general, primary education consists of six to eight years of schooling starting at the age of fve to seven, although this varies between, and sometimes within, countries. Globally, around 89% of children aged six to twelve are enrolled in primary education, and this proportion is rising.[23] Under the Education For All programs driven by UNESCO, most countries have committed to achieving universal enrollment in primary education by 2015, and in many countries, it is compulsory. Te division between primary and secondary education is somewhat arbitrary, but it generally occurs at about eleven or twelve years of age. Some education systems have separate middle schools, with the transition to the fnal stage of secondary education taking place at around the age of ffteen. Schools that provide primary education, are mostly referred to as primary schools or elementary schools. Primary schools are often subdivided into infant schools and junior school. In India, for example, compulsory education spans over twelve years, with eight years of elementary education, fve years of primary schooling and three years of upper primary schooling. Various states in the republic of India provide 12 years of compulsory school education based on a national curriculum framework designed by the National Council of Educational Research and Training.

Secondary

In most contemporary educational systems of the world, secondary education comprises the formal education that occurs during adolescence. In the United States, Canada, and Australia, primary and secondary education together are sometimes referred to as K-12 education, and in New Zealand Year 1–13 is used. Te purpose of secondary education can be to give common knowledge, to prepare for higher education, or to train directly in a profession.[citation needed] Secondary education in the United States did not emerge until 1910, with the rise of large corporations and advancing technology in factories, which required skilled workers. In order to meet this new job demand, high schools were created, with a curriculum focused on practical job skills that would better prepare students for white collar or skilled blue collar work. Tis proved benefcial for both employers and employees, since the improved human capital lowered costs for the employer, while skilled employees received higher wages.[citation needed] Secondary education has a longer history in Europe, where grammar schools or academies date from as early as the 6th century, [a] in the form of public schools, fee-paying schools, or charitable educational foundations, which themselves date even further back.[citation needed] It spans the period between the typically universal compulsory, primary education to the optional, selective tertiary, "postsecondary", or "higher" education of ISCED 5 and 6 (e.g. university), and the ISCED 4 Further education or vocational school.[18] Depending on the system, schools for this period, or a part of it, maybe called secondary or high schools, gymnasiums, lyceums, middle schools, colleges, or vocational schools. Te exact meaning of any of these terms varies from one system to another. Te exact boundary between primary and secondary education also varies from country to country and even within them but is generally around the seventh to the tenth year of schooling.[citation needed] Lower secondary education Programs at ISCED level 2, lower secondary education are usually organized around a more subject-oriented curriculum; diﬀering from primary education. Teachers typically have pedagogical training in the specifc subjects and, more often than at ISCED level 1, a class of students will have several teachers, each with specialized knowledge of the subjects they teach. Programmes at ISCED level 2, aim is to lay the foundation for lifelong learning and human development upon introducing

311 theoretical concepts across a broad range of subjects which can be developed in future stages. Some education systems may offer vocational education programs during ISCED level 2 providing skills relevant to employment. [18] Upper secondary education Programs at ISCED level 3, or upper secondary education, are typically designed to complete the secondary education process. Tey lead to skills relevant to employment and the skill necessary to engage in tertiary courses. Tey offer students more varied, specialized and in-depth instruction. Tey are more differentiated, with range of options and learning streams. [18]

Community colleges oﬀer another option at this transitional stage of education. Tey provide nonresidential junior college courses to people living in a particular area. Tertiary (higher)

Universities often host prominent guest speakers for student audiences, e.g. First Lady of the United States Michelle Obama delivering remarks at Peking University, Beijing, China Higher education, also called tertiary, third stage, or postsecondary education, is the non-compulsory educational level that follows the completion of a school such as a high school or secondary school. Tertiary education is normally taken to include undergraduate and postgraduate education, as well as vocational education and training. Colleges and universities mainly provide tertiary education. Collectively, these are sometimes known as tertiary institutions. Individuals who complete tertiary education generally receive certifcates, diplomas, or academic degrees. Te ISCED distinguishes 4 levels of tertiary education. ISCED 6 is equivalent to a frst degree, ISCED 7 is equivalent to a masters or an advanced professional qualifcation and ISCED 8 is an advanced research qualifcation, usually concluding with the submission and defence of a substantive dissertation of publishable quality based on original research. [24] Te category ISCED 5 is reserved for short-cycle courses of requiring degree level study. [24] Higher education typically involves work towards a degree-level or foundation degree qualifcation. In most developed countries, a high proportion of the population (up to 50%) now enter higher education at some time in their lives. Higher education is therefore very important to national economies, both as a signifcant industry in its own right and as a source of trained and educated personnel for the rest of the economy. University education includes teaching, research, and social services activities, and it includes both the undergraduate level (sometimes referred to as tertiary education) and the graduate (or postgraduate) level (sometimes referred to as graduate school). Some universities are composed of several colleges. One type of university education is a liberal arts education, which can be defned as a "college or university curriculum aimed at imparting broad general knowledge and developing general intellectual capacities, in contrast to a professional, vocational, or technical curriculum."[25] Although what is known today as liberal arts education began in Europe,[26] the term "liberal arts college" is more commonly associated with institutions in the United States such as Williams College or Barnard College.[27] Vocational

Carpentry is normally learned through apprenticeship with an experienced carpenter Main article: Vocational education Vocational education is a form of education focused on direct and practical training for a specifc trade or craft. Vocational education may come in the form of an apprenticeship or internship as well as institutions teaching courses such as carpentry, agriculture, engineering, medicine, architecture and the arts.[citation needed] Post 16 education, adult education and further education involve continued study, but a level no diﬀerent from that found at upper secondary, and are grouped together as ISCED 4, post-secondary non-tertiary education. [24] Special Main article: Special education In the past, those who were disabled were often not eligible for public education. Children with disabilities were repeatedly denied an education by physicians or special tutors. Tese early physicians (people like Itard, Seguin, Howe, Gallaudet) set the foundation for special education today. Tey focused on individualized instruction and functional skills. In its early years, special education was only provided to people with severe disabilities, but more recently it has been opened to anyone who has experienced diﬃculty learning.[28] Other educational forms Alternative

While considered "alternative" today, most alternative systems have existed since ancient times.[citation needed] After the public school system was widely developed beginning in the 19th century, some parents found reasons to be discontented with the new system. Alternative education developed in part as a reaction to perceived limitations and failings of traditional

312 education. A broad range of educational approaches emerged, including alternative schools, self learning, homeschooling, and unschooling. Example alternative schools include Montessori schools, Waldorf schools (or Steiner schools), Friends schools, Sands School, Summerhill School, Walden's Path, Te Peepal Grove School, Sudbury Valley School, Krishnamurti schools, and open classroom schools. Charter schools are another example of alternative education, which have in the recent years grown in numbers in the US and gained greater importance in its public education system.[29][30] In time, some ideas from these experiments and paradigm challenges may be adopted as the norm in education, just as Friedrich Fröbel's approach to early childhood education in 19th-century Germany has been incorporated into contemporary kindergarten classrooms. Other infuential writers and thinkers have included the Swiss humanitarian Johann Heinrich Pestalozzi; the American transcendentalists Amos Bronson Alcott, Ralph Waldo Emerson, and Henry David Toreau; the founders of progressive education, John Dewey and Francis Parker; and educational pioneers such as Maria Montessori and Rudolf Steiner, and more recently John Caldwell Holt, Paul Goodman, Frederick Mayer, George Dennison, and Ivan Illich.[citation needed] Indigenous

Teaching indigenous knowledge, models, and methods in Yanyuan County, Sichuan, China Main article: Indigenous education Indigenous education refers to the inclusion of indigenous knowledge, models, methods, and content within formal and non-formal educational systems. Often in a post-colonial context, the growing recognition and use of indigenous education methods can be a response to the erosion and loss of indigenous knowledge and language through the processes of colonialism. Furthermore, it can enable indigenous communities to "reclaim and revalue their languages and cultures, and in so doing, improve the educational success of indigenous students."[31] Informal learning Main article: Informal learning Informal learning is one of three forms of learning defned by the Organisation for Economic Co-operation and Development (OECD). Informal learning occurs in a variety of places, such as at home, work, and through daily interactions and shared relationships among members of society. For many learners, this includes language acquisition, cultural norms, and manners. In informal learning, there is often a reference person, a peer or expert, to guide the learner. If learners have a personal interest in what they are informally being taught, learners tend to expand their existing knowledge and conceive new ideas about the topic being learned.[32] For example, a museum is traditionally considered an informal learning environment, as there is room for free choice, a diverse and potentially non-standardized range of topics, fexible structures, socially rich interaction, and no externally imposed assessments.[33] While informal learning often takes place outside educational establishments and does not follow a specifed curriculum, it can also occur within educational settings and even during formal learning situations. Educators can structure their lessons to directly utilize their students informal learning skills within the education setting.[32] In the late 19th century, education through play began to be recognized as making an important contribution to child development.[34] In the early 20th century, the concept was broadened to include young adults but the emphasis was on physical activities.[35] L.P. Jacks, also an early proponent of lifelong learning, described education through recreation: "A master in the art of living draws no sharp distinction between his work and his play, his labour and his leisure, his mind and his body, his education and his recreation. He hardly knows which is which. He simply pursues his vision of excellence through whatever he is doing and leaves others to determine whether he is working or playing. To himself, he always seems to be doing both. Enough for him that he does it well."[36] Education through recreation is the opportunity to learn in a seamless fashion through all of life's activities.[37] Te concept has been revived by the University of Western Ontario to teach anatomy to medical students.[37] Self-directed learning Main article: Autodidacticism Autodidacticism (also autodidactism) is self-directed learning. One may become an autodidact at nearly any point in one's life. Notable autodidacts include Abraham Lincoln (U.S. president), Srinivasa Ramanujan (mathematician), Michael Faraday (chemist and physicist), Charles Darwin (naturalist), Tomas Alva Edison (inventor), Tadao Ando (architect), George Bernard Shaw (playwright), Frank Zappa (composer, recording engineer, flm director), and Leonardo da Vinci (engineer, scientist, mathematician).[citation needed] Evidence-based education Main article: Evidence-based education Evidence-based education is the use of well designed scientifc studies to determine which education methods work best. It consists of evidence-based teaching and evidence-based learning. Evidence-based learning methods such as spaced repetition can increase rate of learning.[38] Te evidence-based education movement has its roots in the larger movement towards evidence-based-practices.[citation needed] Open education and electronic technology

313 Main articles: Open education and Educational technology Many large university institutions are now starting to offer free or almost free full courses such as Harvard, MIT and Berkeley teaming up to form edX. Other universities offering open education are prestigious private universities such as Stanford, Princeton, Duke, Johns Hopkins, the University of Pennylvania, and Caltech, as well as notable public universities including Tsinghua, Peking, Edinburgh, University of Michigan, and University of Virginia. Open education has been called the biggest change in the way people learn since the printing press.[39] Despite favourable studies on effectiveness, many people may still desire to choose traditional campus education for social and cultural reasons. [40] Many open universities are working to have the ability to offer students standardized testing and traditional degrees and credentials.[41] Te conventional merit-system degree is currently not as common in open education as it is in campus universities, although some open universities do already offer conventional degrees such as the Open University in the United Kingdom. Presently, many of the major open education sources offer their own form of certifcate. Due to the popularity of open education, these new kind of academic certifcates are gaining more respect and equal "academic value" to traditional degrees.[42] Out of 182 colleges surveyed in 2009 nearly half said tuition for online courses was higher than for campus-based ones.[43] A recent meta-analysis found that online and blended educational approaches had better outcomes than methods that used solely face-to-face interaction.[44] Education sector

Beijing Normal University, which is governed directly by the Chinese Ministry of Education, is an example of collaboration between diﬀerent entities in the education sector Te education sector or education system is a group of institutions (ministries of education, local educational authorities, teacher training institutions, schools, universities, etc.) whose primary purpose is to provide education to children and young people in educational settings. It involves a wide range of people (curriculum developers, inspectors, school principals, teachers, school nurses, students, etc.). Tese institutions can vary according to diﬀerent contexts.[45] Schools deliver education, with support from the rest of the education system through various elements such as education policies and guidelines – to which school policies can refer – curricula and learning materials, as well as pre- and in-service teacher training programmes. Te school environment – both physical (infrastructures) and psychological (school climate) – is also guided by school policies that should ensure the well-being of students when they are in school.[45] Te Organisation for Economic Co-operation and Development has found that schools tend to perform best when principals have full authority and responsibility for ensuring that students are profcient in core subjects upon graduation. Tey must also seek feedback from students for quality-assurance and improvement. Governments should limit themselves to monitoring student profciency.[46] Te education sector is fully integrated into society, through interactions with numerous stakeholders and other sectors. Tese include parents, local communities, religious leaders, NGOs, stakeholders involved in health, child protection, justice and law enforcement (police), media and political leadership.[45]

Professions;

God created each individual with a diﬀerent purpose there are around 43, million professions in 4952 distinctions of professional categories (at an educational level), diﬀerent abilities, for which they can seek employment of which you only have too look into career choice too see how diverse the range is, you can ask god with a prayer what he intended you for; this usually happens naturally at around age 9, you should then go and study something relevant at educational level, univerisity, if your direct purpose is not available consult god further for something relevant. If you don’t you had better ask for your soul purpose and apply this and/or as well, then again some in your spare time. Take good rest and holidays if you work hard you will have learnt and deserved them. By the time you N.e.r.d. if you have fulflled your professional purpose and hopefully some of your soul purpose - God will reward and praise you in such a way, praise and thank him back,

A profession is an occupation founded upon specialized educational training, the purpose of which is to supply disinterested objective counsel and service to others, for a direct and defnite compensation, wholly apart from expectation of other business gain.[1][2] Te term is a truncation of the term "liberal profession", which is, in turn, an Anglicization of the French term "profession libérale". Originally borrowed by English users in the 19th century, it has been re-borrowed by international users from the late 20th, though the (upper-middle) class overtones of the term do not seem to survive retranslation: "liberal professions" are, according to the European Union's Directive on Recognition of Professional Qualifcations (2005/36/EC), "those practiced on the basis of relevant professional qualifcations in a personal, responsible and professionally independent capacity by those providing intellectual and conceptual services in the interest of the client and the public". It has been said that a profession is not a trade[3] and not an industry.[4]

314 Medieval and early modern tradition recognized only three professions: divinity, medicine, and law[5][6] – the so-called "learned professions".[7] Major milestones which may mark an occupation being identifed as a profession include:[6] 1. an occupation becomes a full-time occupation 2. the establishment of a training school 3. the establishment of a university school 4. the establishment of a local association 5. the establishment of a national association of professional ethics 6. the establishment of state licensing laws Applying these milestones to the historical sequence of development in the United States shows surveying achieving professional status frst (note that George Washington, Tomas Jeﬀerson, and Abraham Lincoln all worked as land surveyors before entering politics[citation needed]), followed by medicine, actuarial science, law, dentistry, civil engineering, logistics, architecture and accounting.[8] With the rise of technology and occupational specialization in the 19th century, other bodies began to claim professional status: mechanical engineering, pharmacy, veterinary medicine, psychology, nursing, teaching, librarianship, optometry and social work, each of which could claim, using these milestones, to have become professions by 1900.[9] Just as some professions rise in status and power through various stages, others may decline.[citation needed] Disciplines formalized more recently, such as architecture, now have equally long periods of study associated with them.[10] Although professions may enjoy relatively high status and public prestige, not all professionals earn high salaries, and even within specifc professions there exist signifcant inequalities of compensation; in law, for example, a corporate/insurance defense lawyer working on a billable-hour basis may earn several times what a prosecutor or public defender earns.

Tere is considerable agreement about defning the characteristic features of a profession. Tey have a "professional association, cognitive base, institutionalized training, licensing, work autonomy, colleague control... (and) code of ethics",[22] to which Larson then also adds, "high standards of professional and intellectual excellence," (Larson, p. 221) that "professions are occupations with special power and prestige", (Larson, p.x) and that they comprise "an exclusive elite group," (Larson, p. 20) in all societies. Members of a profession have also been defned as "workers whose qualities of detachment, autonomy, and group allegiance are more extensive than those found among other groups...their attributes include a high degree of systematic knowledge; strong community orientation and loyalty; self-regulation; and a system of rewards defned and administered by the community of workers."[23]

A profession has been further defned as: "a special type of occupation...(possessing) corporate solidarity...prolonged specialized training in a body of abstract knowledge, and a collectivity or service orientation...a vocational sub-culture which comprises implicit codes of behavior, generates an esprit de corps among members of the same profession, and ensures them certain occupational advantages...(also) bureaucratic structures and monopolistic privileges to perform certain types of work...professional literature, legislation, etc."[24]

A critical characteristic of a profession is the need to cultivate and exercise professional discretion - that is, the ability to make case by case judgements that cannot be determined by an absolute rule or instruction.[25]

Sociotechnical system design, a philosophy and tools for participative designing of work arrangements and supporting processes - for organizational purpose, quality, safety, economics and customer requirements in core work processes, the quality of peoples experience at work and the needs of society

In political science, the term engineering has been borrowed for the study of the subjects of social engineering and political engineering, which deal with forming political and social structures using engineering methodology coupled with political science principles. Financial engineering has similarly borrowed the term.

Culture

Culture (/ˈkʌltʃər/) is the social behavior and norms found in human societies. Culture is considered a central concept in anthropology, encompassing the range of phenomena that are transmitted through social learning in human societies. Some aspects of human behavior, social practices such as culture, expressive forms such as art, music, dance, ritual, and religion, and technologies such as tool usage, cooking, shelter, and clothing are said to be cultural universals, found in all human societies. Te concept of material culture covers the physical expressions of culture, such as technology, architecture and art, whereas the immaterial aspects of culture such as principles of social organization (including practices of political 315 organization and social institutions), mythology, philosophy, literature (both written and oral), and science comprise the intangible cultural heritage of a society.

In the humanities, one sense of culture as an attribute of the individual has been the degree to which they have cultivated a particular level of sophistication in the arts, sciences, education, or manners. Te level of cultural sophistication has also sometimes been seen to distinguish civilizations from less complex societies. Such hierarchical perspectives on culture are also found in class-based distinctions between a high culture of the social elite and a low culture, popular culture, or folk culture of the lower classes, distinguished by the stratifed access to cultural capital. In common parlance, culture is often used to refer specifcally to the symbolic markers used by ethnic groups to distinguish themselves visibly from each other such as body modifcation, clothing or jewelry. Mass culture refers to the mass-produced and mass mediated forms of consumer culture that emerged in the 20th century. Some schools of philosophy, such as Marxism and critical theory, have argued that culture is often used politically as a tool of the elites to manipulate the lower classes and create a false consciousness, and such perspectives are common in the discipline of cultural studies. In the wider social sciences, the theoretical perspective of cultural materialism holds that human symbolic culture arises from the material conditions of human life, as humans create the conditions for physical survival, and that the basis of culture is found in evolved biological dispositions.

When used as a count noun, a "culture" is the set of customs, traditions, and values of a society or community, such as an ethnic group or nation. Culture is the set of knowledge acquired over time. In this sense, multiculturalism values the peaceful coexistence and mutual respect between diﬀerent cultures inhabiting the same planet. Sometimes "culture" is also used to describe specifc practices within a subgroup of a society, a subculture (e.g. "bro culture"), or a counterculture. Within cultural anthropology, the ideology and analytical stance of cultural relativism holds that cultures cannot easily be objectively ranked or evaluated because any evaluation is necessarily situated within the value system of a given culture. Yet within philosophy, this stance of cultural relativism is undermined and made inapplicable since such value judgement is itself a product of a given culture.

A counterculture (also written counter-culture) is a subculture whose values and norms of behavior diﬀer substantially from those of mainstream society, often in opposition to mainstream cultural mores. A countercultural movement expresses the ethos and aspirations of a specifc population during a well-defned era. When oppositional forces reach critical mass, countercultures can trigger dramatic cultural changes. Prominent examples of countercultures in Europe and North America include Romanticism (1790–1840), Bohemianism (1850–1910), the more fragmentary counterculture of the Beat Generation (1944–1964), followed by the globalized counterculture of the 1960s (1964–1974), usually associated with the hippie subculture and the diversifed Punk subculture of the 1980s.

Collectivism is a cultural value that is characterized by emphasis on cohesiveness among individuals and prioritization of the group over self. Individuals or groups that ascribe to a collectivistic worldview tend to fnd common values and goals as particularly salient[1] and demonstrate greater orientation toward in-group than toward out-group. Te term “in-group” is thought to be more diﬀusely defned for collectivistic individuals to include societal units ranging from the nuclear family to a religious or racial/ethnic group. Meta-analytic fndings support that collectivism shows a consistent association with discrete values, interpersonal patterns of interaction, cognition, perception and self-construal. Collectivism is often discussed alongside the cultural value of individualism, but these are two distinct concepts and are not considered to be opposites.

Cultural anthropology is a branch of anthropology focused on the study of cultural variation among humans. It is in contrast to social anthropology, which perceives cultural variation as a subset of the anthropological constant.

Cultural anthropology has a rich methodology, including participant observation (often called feldwork because it requires the anthropologist spending an extended period of time at the research location), interviews, and surveys.

One of the earliest articulations of the anthropological meaning of the term "culture" came from Sir Edward Tylor who writes on the frst page of his 1871 book: "Culture, or civilization, taken in its broad, ethnographic sense, is that complex whole which includes knowledge, belief, art, morals, law, custom, and any other capabilities and habits acquired by man as a member of society.” Te term "civilization" later gave way to defnitions given by V. Gordon Childe, with culture forming an umbrella term and civilization becoming a particular kind of culture.

Te anthropological concept of "culture" refects in part a reaction against earlier Western discourses based on an opposition between "culture" and "nature", according to which some human beings lived in a "state of nature".[citation needed] Anthropologists have argued that culture is "human nature", and that all people have a capacity to classify experiences, encode classifcations symbolically (i.e. in language), and teach such abstractions to others.

Since humans acquire culture through the learning processes of enculturation and socialization, people living in different places or different circumstances develop different cultures. Anthropologists have also pointed out that through culture

316 people can adapt to their environment in non-genetic ways, so people living in diﬀerent environments will often have diﬀerent cultures. Much of anthropological theory has originated in an appreciation of and interest in the tension between the local (particular cultures) and the global (a universal human nature, or the web of connections between people in distinct places/circumstances).

Te rise of cultural anthropology took place within the context of the late 19th century, when questions regarding which cultures were "primitive" and which were "civilized" occupied the minds of not only Marx and Freud, but many others. Colonialism and its processes increasingly brought European thinkers into direct or indirect contact with "primitive others." Te relative status of various humans, some of whom had modern advanced technologies that included engines and telegraphs, while others lacked anything but face-to-face communication techniques and still lived a Paleolithic lifestyle, was of interest to the frst generation of cultural anthropologists.

Parallel with the rise of cultural anthropology in the United States, social anthropology, in which sociality is the central concept and which focuses on the study of social statuses and roles, groups, institutions, and the relations among them— developed as an academic discipline in Britain and in France. Te umbrella term socio-cultural anthropology draws upon both cultural and social anthropology traditions.

Broadcasting

Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum (radio waves), in a one-to-many model. Broadcasting began with AM radio, which came into popular use around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, all forms of electronic communication (early radio, telephone, and telegraph) were one-to-one, with the message intended for a single recipient. Te term broadcasting evolved from its use as the agricultural method of sowing seeds in a feld by casting them broadly about. It was later adopted for describing the widespead distribution of information by printed materials or by telegraph.Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898.

Over the air broadcasting is usually associated with radio and television, though in recent years both radio and television transmissions have begun to be distributed by cable (cable television). Te receiving parties may include the general public or a relatively small subset; the point is that anyone with the appropriate receiving technology and equipment (e.g., a radio or television set) can receive the signal. Te feld of broadcasting includes both government-managed services such as public radio, community radio and public television, and private commercial radio and commercial television. Te U.S. Code of Federal Regulations, title 47, part 97 defnes "broadcasting" as "transmissions intended for reception by the general public, either direct or relayed”. Private or two-way telecommunications transmissions do not qualify under this defnition. For example, amateur ("ham") and citizens band (CB) radio operators are not allowed to broadcast. As defned, "transmitting" and "broadcasting" are not the same.

Transmission of radio and television programs from a radio or television station to home receivers by radio waves is referred to as "over the air" (OTA) or terrestrial broadcasting and in most countries requires a broadcasting license. Transmissions using a wire or cable, like cable television (which also retransmits OTA stations with their consent), are also considered broadcasts, but do not necessarily require a license (though in some countries, a license is required). In the 2000s, transmissions of television and radio programs via streaming digital technology have increasingly been referred to as broadcasting as well.

Radio is the technology of using radio waves to carry information, such as sound, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating felds induce an alternating current in the conductor. Te information in the waves can be extracted and transformed back into its original form.

Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and radio waves into an electric current. An antenna can be used for both transmitting and receiving. Te electrical resonance of tuned circuits in radios allow individual frequencies to be selected. Te electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form that is usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.

317 A radio communication system requires a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.

Television (TV) is a telecommunication medium used for transmitting moving images in monochrome (black and white), or in colour, and in two or three dimensions and sound. Te term can refer to a television set, a television program ("TV show"), or the medium of television transmission. Television is a mass medium for entertainment, education, news, politics, gossip and advertising.

Television became available in crude experimental forms in the late 1920s, but it would still be several years before the new technology was marketed to consumers. After World War II, an improved form of black-and-white TV broadcasting became popular in the United States and Britain, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for infuencing public opinion. In the mid-1960s, color broadcasting was introduced in the US and most other developed countries. Te availability of multiple types of storage media such as Betamax, VHS tape, local disks, DVDs, fash drives, high-defnition Blu-ray Discs, and digital video recorders have enabled viewers to watch prerecorded material—such as movies— at home on their own time schedule. For many reasons, the storage of television and video programming now occurs on the cloud. At the end of the frst decade of the 2000s, digital television transmissions greatly increased in popularity. Another development was the move from standard-defnition television (SDTV) (576i, with 576 interlaced lines of resolution and 480i) to high-defnition television (HDTV), which provides a resolution that is substantially higher. HDTV may be transmitted in various formats: 1080p, 1080i and 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netfix, Amazon Video, iPlayer, Hulu, Roku and Chromecast.

In 2013, 79% of the world's households owned a television set. Te replacement of early bulky, high-voltage cathode ray tube (CRT) screen displays with compact, energy-eﬃcient, fat-panel alternative technologies such as plasma displays, LCDs (both fuorescent-backlit and LED), and OLED displays was a hardware revolution that began with computer monitors in the late 1990s. Most TV sets sold in the 2000s were fat-panel, mainly LEDs. Major manufacturers announced the discontinuation of CRT, DLP, plasma, and even fuorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are expected to be gradually replaced by OLEDs. Also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s.

Television signals were initially distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by coaxial cable or optical fber, satellite systems and, since the 2000s via the Internet. Until the early 2000s, these were transmitted as analog signals, but a transition to digital television is expected to be completed worldwide by the late 2010s. A standard television set is composed of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a video monitor rather than a television.

Dance

Dance is a performing art form consisting of purposefully selected sequences of human movement. Tis movement has aesthetic and symbolic value, and is acknowledged as dance by performers and observers within a particular culture.[nb 1] Dance can be categorized and described by its choreography, by its repertoire of movements, or by its historical period or place of origin.

An important distinction is to be drawn between the contexts of theatrical and participatory dance, although these two categories are not always completely separate; both may have special functions, whether social, ceremonial, competitive, erotic, martial, or sacred/liturgical. Other forms of human movement are sometimes said to have a dance-like quality, including martial arts, gymnastics, cheerleading, fgure skating, synchronized swimming, marching bands, and many other forms of athletics.

Teatrical dance, also called performance or concert dance, is intended primarily as a spectacle, usually a performance upon a stage by virtuoso dancers. It often tells a story, perhaps using mime, costume and scenery, or else it may simply interpret the musical accompaniment, which is often specially composed. Examples are western ballet and modern dance, Classical Indian dance and Chinese and Japanese song and dance dramas. Most classical forms are centred upon dance alone, but performance dance may also appear in opera and other forms of musical theatre.

318 Participatory dance, on the other hand, whether it be a folk dance, a social dance, a group dance such as a line, circle, chain or square dance, or a partner dance such as is common in western Western ballroom dancing, is undertaken primarily for a common purpose, such as social interaction or exercise, of participants rather than onlookers. Such dance seldom has any narrative. A group dance and a corps de ballet, a social partner dance and a pas de deux, diﬀer profoundly. Even a solo dance may be undertaken solely for the satisfaction of the dancer. Participatory dancers often all employ the same movements and steps but, for example, in the rave culture of electronic dance music, vast crowds may engage in free dance, uncoordinated with those around them. On the other hand, some cultures lay down strict rules as to the particular dances in which, for example, men, women and children may or must participate.

Archeological evidence for early dance includes 9,000-year-old paintings in India at the Rock Shelters of Bhimbetka, and Egyptian tomb paintings depicting dancing fgures, dated c. 3300 BC. It has been proposed that before the invention of written languages, dance was an important part of the oral and performance methods of passing stories down from generation to generation.[5] Te use of dance in ecstatic trance states and healing rituals (as observed today in many contemporary "primitive" cultures, from the Brazilian rainforest to the Kalahari Desert) is thought to have been another early factor in the social development of dance.

Greek bronze statuette of a veiled and masked dancer, 3rd-2nd century BC, Alexandria, Egypt. References to dance can be found in very early recorded history; Greek dance (horos) is referred to by Plato, Aristotle, Plutarch and Lucian. Te Bible and Talmud refer to many events related to dance, and contain over 30 diﬀerent dance terms. In Chinese pottery as early as the Neolithic period, groups of people are depicted dancing in a line holding hands, and the earliest Chinese word for "dance" is found written in the oracle bones. Dance is further described in the Lüshi Chunqiu. Primitive dance in ancient China was associated with sorcery and shamanic rituals.

During the frst millennium BCE in India, many texts were composed which attempted to codify aspects of daily life. Bharata Muni's Natyashastra (literally "the text of dramaturgy") is one of the earlier texts. It mainly deals with drama, in which dance plays an important part in Indian culture. It categorizes dance into four types - secular, ritual, abstract, and, interpretive - and into four regional varieties. Te text elaborates various hand-gestures (mudras) and classifes movements of the various limbs, steps and so on. A strong continuous tradition of dance has since continued in India, through to modern times, where it continues to play a role in culture, ritual, and, notably, the Bollywood entertainment industry. Many other contemporary dance forms can likewise be traced back to historical, traditional, ceremonial, and ethnic dance.

Dance is generally, though not exclusively, performed with the accompaniment of music and may or may not be performed in time to such music. Some dance (such as tap dance) may provide its own audible accompaniment in place of (or in addition to) music. Many early forms of music and dance were created for each other and are frequently performed together. Notable examples of traditional dance/music couplings include the jig, waltz, tango, disco, and salsa. Some musical genres have a parallel dance form such as baroque music and baroque dance; other varieties of dance and music may share nomenclature but developed separately, such as classical music and classical ballet.

Rhythm and dance are deeply linked in history and practice. Te American dancer Ted Shawn wrote; "Te conception of rhythm which underlies all studies of the dance is something about which we could talk forever, and still not fnish."[13] A musical rhythm requires two main elements; frst, a regularly-repeating pulse (also called the "beat" or "tactus") that establishes the tempo and, second, a pattern of accents and rests that establishes the character of the metre or basic rhythmic pattern. Te basic pulse is roughly equal in duration to a simple step or gesture.

Dances generally have a characteristic tempo and rhythmic pattern. Te tango, for example, is usually danced in 2/4 time at approximately 66 beats per minute. Te basic slow step, called a "slow", lasts for one beat, so that a full "right–left" step is equal to one 2/4 measure. Te basic forward and backward walk of the dance is so counted - "slow-slow" - while many additional fgures are counted "slow - quick-quick.

Just as musical rhythms are defned by a pattern of strong and weak beats, so repetitive body movements often depends on alternating "strong" and "weak" muscular movements. Given this alternation of left-right, of forward-backward and rise-fall, along with the bilateral symmetry of the human body, it is natural that many dances and much music are in duple and quadruple meter. However, since some such movements require more time in one phase than the other - such as the longer time required to lift a hammer than to strike - some dance rhythms fall equally naturally into triple metre. Occasionally, as in the folk dances of the Balkans, dance traditions depend heavily on more complex rhythms. Further, complex dances composed of a fxed sequence of steps always require phrases and melodies of a certain fxed length to accompany that sequence.

319 Lululaund - Te Dancing Girl (painting and silk cloth. A.L. Baldry 1901, before p.107), Te inscription reads; "Dancing is a form of rhythm/ Rhythm is a form of music/ Music is a form of thought/ And thought is a form of divinity.” Te very act of dancing, the steps themselves, generate an "initial skeleton of rhythmic beats" that must have preceded any separate musical accompaniment, while dance itself, as much as music, requires time-keeping just as utilitarian repetitive movements such as walking, hauling and digging take on, as they become refned, something of the quality of dance.

Musical accompaniment therefore arose in the earliest dance, so that ancient Egyptians attributed the origin of the dance to the divine Athotus, who was said to have observed that music accompanying religious rituals caused participants to move rhythmically and to have brought these movements into proportional measure. Te same idea, that dance arises from musical rhythm, is still found in renaissance Europe in the works of the dancing master Guglielmo Ebreo da Pesaro who speaks of dance as a physical movement that arises from and expresses inward, spiritual motion agreeing with the "measures and perfect concords of harmony" that fall upon the human ear, while, earlier, Mechthild of Magdeburg, seizing upon dance as a symbol of the holy life foreshadowed in Jesus' saying "I have piped and ye have not danced", writes;

I can not dance unless thou leadest. If thou wouldst have me spring aloft, sing thou and I will spring, into love and from love to knowledge and from knowledge to ecstasy above all human sense.

Toinot Arbeau's celebrated 16th century dance-treatise Orchésographie, indeed, begins with defnitions of over eighty distinct drum-rhythms.

As has been shown above, dance has been represented through the ages as having emerged as a response to music yet, as Lincoln Kirstein implied, it is at least as likely that primitive music arose from dance. Shawn concurs, stating that dance "was the frst art of the human race, and the matrix out of which all other arts grew" and that even the "metre in our poetry today is a result of the accents necessitated by body movement, as the dancing and reciting were performed simultaneously" - an assertion somewhat supported by the common use of the term "foot" to describe the fundamental rhythmic units of poetry.

Scholes, not a dancer but a musician, oﬀers support for this view, stating that the steady measures of music, of two, three or four beats to the bar, its equal and balanced phrases, regular cadences, contrasts and repetitions, may all be attributed to the "incalculable" infuence of dance upon music.

Émile Jaques-Dalcroze, primarily a musician and teacher, relates how a study of the physical movements of pianists led him "to the discovery that musical sensations of a rhythmic nature call for the muscular and nervous response of the whole organism", to develop "a special training designed to regulate nervous reactions and eﬀect a co-ordination of muscles and nerves" and ultimately to seek the connections between "the art of music and the art of dance", which he formulated into his system of eurhythmics. He concluded that "musical rhythm is only the transposition into sound of movements and dynamisms spontaneously and involuntarily expressing emotion".

Hence, though doubtless, as Shawn asserts, "it is quite possible to develop the dance without music and... music is perfectly capable of standing on its own feet without any assistance from the dance", nevertheless the "two arts will always be related and the relationship can be proftable both to the dance and to music", the precedence of one art over the other being a moot point. Te common ballad measures of hymns and folk-songs takes their name from dance, as does the carol, originally a circle dance. Many purely musical pieces have been named "waltz" or "minuet", for example, while many concert dances have been produced that are based upon abstract musical pieces, such as 2 and 3 Part Inventions, Adams Violin Concerto and Andantino. Similarly, poems are often structured and named after dances or musical works, while dance and music have both drawn their conception of "measure" or "metre" from poetry.

Shawn quotes with approval the statement of Dalcroze that, while the art of musical rhythm consists in diﬀerentiating and combining time durations, pauses and accents "according to physiological law", that of "plastic rhythm" (i.e. dance) "is to designate movement in space, to interpret long time-values by slow movements and short ones by quick movements, regulate pauses by their divers successions and express sound accentuations in their multiple nuances by additions of bodily weight, by means of muscular innervations".

Shawn nevertheless points out that the system of musical time is a "man-made, artifcial thing.... a manufactured tool, whereas rhythm is something that has always existed and depends on man not at all", being "the continuous fowing time which our human minds cut up into convenient units", suggesting that music might be revivifed by a return to the values and the time-perception of dancing.

Te early-20th-century American dancer Helen Moller stated simply that "it is rhythm and form more than harmony and color which, from the beginning, has bound music, poetry and dancing together in a union that is indissoluble."

320 Concert dance, like opera, generally depends for its large-scale form upon a narrative dramatic structure. Te movements and gestures of the choreography are primarily intended to mime the personality and aims of the characters and their part in the plot. Such theatrical requirements tend towards longer, freer movements than those usual in non-narrative dance styles. On the other hand, the ballet blanc, developed in the 19th century, allows interludes of rhythmic dance that developed into entirely "plotless" ballets in the 20th century and that allowed fast, rhythmic dance-steps such as those of the petit allegro. A well-known example is Te Cygnets' Dance in act two of Swan Lake.

Te ballet developed out of courtly dramatic productions of 16th- and 17th-century France and Italy and for some time dancers performed dances developed from those familiar from the musical suite, all of which were defned by defnite rhythms closely identifed with each dance. Tese appeared as character dances in the era of romantic nationalism.

Ballet reached widespread vogue in the romantic era, accompanied by a larger orchestra and grander musical conceptions that did not lend themselves easily to rhythmic clarity and by dance that emphasised dramatic mime. A broader concept of rhythm was needed, that which Rudolf Laban terms the "rhythm and shape" of movement that communicates character, emotion and intention,[30] while only certain scenes required the exact synchronisation of step and music essential to other dance styles, so that, to Laban, modern Europeans seemed totally unable to grasp the meaning of "primitive rhythmic movements", a situation that began to change in the 20th century with such productions as Igor Stravinsky's Te Rite of Spring with its new rhythmic language evoking primal feelings of a primitive past.

Indian classical dance styles, like ballet, are often in dramatic form, so that there is a similar complementarity between narrative expression and "pure" dance. In this case, however, the two are separately defned, though not always separately performed. Te rhythmic elements, which are abstract and technical, are known as nritta. Both this and expressive dance (nritya), though, are closely tied to the rhythmic system (tala). Teachers have adapted the spoken rhythmic mnemonic system called bol to the needs of dancers.

Japanese classical dance-theatre styles such as Kabuki and Noh, like Indian dance-drama, distinguish between narrative and abstract dance productions. Te three main categories of kabuki are jidaimono (historical), sewamono (domestic) and shosagoto (dance pieces). Somewhat similarly, Noh distinguishes between Geki Noh, based around the advancement of plot and the narration of action, and Furyū Noh, dance pieces involving acrobatics, stage properties, multiple characters and elaborate stage action.

Social dances, those intended for participation rather than for an audience, may include various forms of mime and narrative, but are typically set much more closely to the rhythmic pattern of music, so that terms like waltz and polka refer as much to musical pieces as to the dance itself. Te rhythm of the dancers' feet may even form an essential part of the music, as in tap dance. African dance, for example, is rooted in fxed basic steps, but may also allow a high degree of rhythmic interpretation: the feet or the trunk mark the basic pulse while cross-rhythms are picked up by shoulders, knees, or head, with the best dancers simultaneously giving plastic expression to all the elements of the polyrhythmic pattern.

Dance in Africa is deeply integrated into society and major events in a community are frequently refected in dances: dances are performed for births and funerals, weddings and wars.:13 Traditional dances impart cultural morals, including religious traditions and sexual standards; give vent to repressed emotions, such as grief; motivate community members to cooperate, whether fghting wars or grinding grain; enact spiritual rituals; and contribute to social cohesiveness.

Tousands of dances are performed around the continent. Tese may be divided into traditional, neotraditional, and classical styles: folkloric dances of a particular society, dances created more recently in imitation of traditional styles, and dances transmitted more formally in schools or private lessons.:18 African dance has been altered by many forces, such as European missionaries and colonialist governments, who often suppressed local dance traditions as licentious or distracting. Dance in contemporary African cultures still serves its traditional functions in new contexts; dance may celebrate the inauguration of a hospital, build community for rural migrants in unfamiliar cities, and be incorporated into Christian church ceremonies.

All Indian classical dances are to varying degrees rooted in the Natyashastra and therefore share common features: for example, the mudras (hand positions), some body positions, and the inclusion of dramatic or expressive acting or abhinaya. Indian classical music provides accompaniment and dancers of nearly all the styles wear bells around their ankles to counterpoint and complement the percussion.

Tere are now many regional varieties of Indian classical dance. Dances like "Odra Magadhi", which after decades long debate, has been traced to present day Mithila, Odisha region's dance form of Odissi (Orissi), indicate infuence of dances in cultural interactions between diﬀerent regions.

321 Te Punjab area overlapping India and Pakistan is the place of origin of Bhangra. It is widely known both as a style of music and a dance. It is mostly related to ancient harvest celebrations, love, patriotism or social issues. Its music is coordinated by a musical instrument called the 'Dhol'. Bhangra is not just music but a dance, a celebration of the harvest where people beat the dhol (drum), sing Boliyaan (lyrics) and dance. It developed further with the Vaisakhi festival of the Sikhs.

Te dances of Sri Lanka include the devil dances (yakun natima), a carefully crafted ritual reaching far back into Sri Lanka's pre-Buddhist past that combines ancient "Ayurvedic" concepts of disease causation with psychological manipulation and combines many aspects including Sinhalese cosmology. Teir infuence can be seen on the classical dances of Sri Lanka.

Two classical ballet dancers perform a sequence of Te Nutcracker, one of the best known works of classical dance: Te dances of the Middle East are usually the traditional forms of circle dancing which are modernized to an extent. Tey would include dabke, tamzara, Assyrian folk dance, Kurdish dance, Armenian dance and Turkish dance, among others. All these forms of dances would usually involve participants engaging each other by holding hands or arms (depending on the style of the dance). Tey would make rhythmic moves with their legs and shoulders as they curve around the dance foor. Te head of the dance would generally hold a cane or handkerchief

Folk dances vary across Europe and may date back hundreds or thousands of years, but many have features in common such as group participation led by a caller, hand-holding or arm-linking between participants, and fxed musical forms known as caroles. Some, such as the maypole dance are common to many nations, while others such as the céilidh and the polka are deeply-rooted in a single culture. Some European folk dances such as the square dance were brought to the New World and subsequently became part of American culture.

Ballet developed frst in Italy and then in France from lavish court spectacles that combined music, drama, poetry, song, costumes and dance. Members of the court nobility took part as performers. During the reign of Louis XIV, himself a dancer, dance became more codifed. Professional dancers began to take the place of court amateurs, and ballet masters were licensed by the French government. Te frst ballet dance academy was the Académie Royale de Danse (Royal Dance Academy), opened in Paris in 1661. Shortly thereafter, the frst institutionalized ballet troupe, associated with the Academy, was formed; this troupe began as an all-male ensemble but by 1681 opened to include women as well.

20th century concert dance brought an explosion of innovation in dance style characterized by an exploration of freer technique. Early pioneers of what became known as modern dance include Loie Fuller, Isadora Duncan, Mary Wigman and Ruth St. Denis. Te relationship of music to dance serves as the basis for Eurhythmics, devised by Emile Jaques-Dalcroze, which was infuential to the development of Modern dance and modern ballet through artists such as Marie Rambert. Eurythmy, developed by Rudolf Steiner and Marie Steiner-von Sivers, combines formal elements reminiscent of traditional dance with the new freer style, and introduced a complex new vocabulary to dance. In the 1920s, important founders of the new style such as Martha Graham and Doris Humphrey began their work. Since this time, a wide variety of dance styles have been developed; see Modern dance.

Street samba dancers perform in carnival parades and contests, African American dance developed in everyday spaces, rather than in dance studios, schools or companies. Tap dance, disco, jazz dance, swing dance, hip hop dance, the lindy hop with its relationship to rock and roll music and rock and roll dance have had a global infuence. Dance styles fusing classical ballet technique with African-American dance have also appeared in the 21st century, including Hiplet.

Dance is central to Latin American social life and culture. Brazilian Samba, Argentinian tango, and Cuban salsa are internationally popular partner dances, and other national dances—merengue, cueca, plena, jarabe, joropo, marinera, cumbia, and others—are important components of their respective countries' cultures. Traditional Carnival festivals incorporate these and other dances in enormous celebrations.

Dance has played an important role in forging a collective identity among the many cultural and ethnic groups of Latin America. Dance served to unite the many African, European, and indigenous peoples of the region. Certain dance genres, such as capoeira, and body movements, especially the characteristic quebrada or pelvis swing, have been variously banned and celebrated throughout Latin American history.

Te modern form of Hip Hop and name originated in New York, specifcally in the area known as the Bronx. It was created for those who struggled in society and didn't seem to have a voice in the community that surrounded them because of their lack of wealth. It helped those in the same situation come together and speak about diﬃcult topics by using movement and feeling.

322 Film, also called a movie, motion picture, theatrical flm, or photoplay, is a series of still images that when shown on a screen create an illusion of motion images (due to the phi phenomenon). See glossary of motion picture terms.

Tis optical illusion causes the audience to perceive continuous motion between separate objects viewed rapidly in succession. Te process of flmmaking is both an art and an industry. A flm is created by photographing actual scenes with a motion picture camera; by photographing drawings or miniature models using traditional animation techniques; by means of CGI and computer animation; or by a combination of some or all of these techniques and other visual eﬀects.

Te word "cinema", short for cinematography, is often used to refer to the industry of flms and flmmaking or to the art of flmmaking itself. Te contemporary defnition of cinema is the art of simulating experiences to communicate ideas, stories, perceptions, feelings, beauty or atmosphere by the means of recorded or programmed moving images along with other sensory stimulations.

Films were originally recorded onto plastic flm through a photochemical process and then shown through a movie projector onto a large screen. Contemporary flms are now often fully digital through the entire process of production, distribution, and exhibition from start to fnish, while flms recorded in a photochemical form traditionally included an analogous optical soundtrack, which is a graphic recording of the spoken words, music and other sounds that accompany the images. It runs along a portion of the flm exclusively reserved for it and is not projected.

Films are cultural artifacts created by specifc cultures. Tey refect those cultures, and, in turn, aﬀect them. Film is considered to be an important art form, a source of popular entertainment, and a powerful medium for educating—or indoctrinating—citizens. Te visual basis of flm gives it a universal power of communication. Some flms have become popular worldwide attractions by using dubbing or subtitles to translate the dialog into the language of the viewer. Some have criticized the flm industry's glorifcation of violence and its potentially negative treatment of women.

Te individual images that make up a flm are called frames. During projection of traditional flms, a rotating shutter causes intervals of darkness as each frame, in turn, is moved into position to be projected, but the viewer does not notice the interruptions because of an eﬀect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after the source has been removed. Te perception of motion is due to a psychological eﬀect called phi phenomenon.

Te name "flm" originates from the fact that photographic flm (also called flm stock) has historically been the medium for recording and displaying motion pictures. Many other terms exist for an individual motion picture, including picture, picture show, moving picture, photoplay, and fick. Te most common term in the United States is movie, while in Europe flm is preferred. Terms for the feld, in general, include the big screen, the silver screen, the movies, and cinema; the latter is commonly used in scholarly texts and critical essays, especially by European writers. In early years, the word sheet was sometimes used instead of screen.

Preceding flm in origin by thousands of years, early plays and dances had elements common to flm: scripts, sets, costumes, production, direction, actors, audiences, storyboards and scores. Much terminology later used in flm theory and criticism apply, such as mise en scène (roughly, the entire visual picture at any one time). Owing to the lack of any technology for doing so, the moving images and sounds could not be recorded for replaying as with flm.

Te magic lantern, probably created by Christiaan Huygens in the 1650s, could be used to project animation, which was achieved by various types of mechanical slides. Typically, two glass slides, one with the stationary part of the picture and the other with the part that was to move, would be placed one on top of the other and projected together, then the moving slide would be hand-operated, either directly or by means of a lever or other mechanism. Chromotrope slides, which produced eye-dazzling displays of continuously cycling abstract geometrical patterns and colors, were operated by means of a small crank and pulley wheel that rotated a glass disc.

In the mid-19th century, inventions such as Joseph Plateau's phenakistoscope and the later zoetrope demonstrated that a carefully designed sequence of drawings, showing phases of the changing appearance of objects in motion, would appear to show the objects actually moving if they were displayed one after the other at a suﬃciently rapid rate. Tese devices relied on the phenomenon of persistence of vision to make the display appear continuous even though the observer's view was actually blocked as each drawing rotated into the location where its predecessor had just been glimpsed. Each sequence was limited to a small number of drawings, usually twelve, so it could only show endlessly repeating cyclical motions. By the late 1880s, the last major device of this type, the praxinoscope, had been elaborated into a form that employed a long coiled band containing hundreds of images painted on glass and used the elements of a magic lantern to project them onto a screen.

Te use of sequences of photographs in such devices was initially limited to a few experiments with subjects photographed in a series of poses because the available emulsions were not sensitive enough to allow the short exposures needed to

323 photograph subjects that were actually moving. Te sensitivity was gradually improved and in the late 1870s, Eadweard Muybridge created the frst animated image sequences photographed in real-time. A row of cameras was used, each, in turn, capturing one image on a photographic glass plate, so the total number of images in each sequence was limited by the number of cameras, about two dozen at most. Muybridge used his system to analyze the movements of a wide variety of animal and human subjects. Hand-painted images based on the photographs were projected as moving images by means of his zoopraxiscope.

By the end of the 1880s, the introduction of lengths of celluloid photographic flm and the invention of motion picture cameras, which could photograph an indefnitely long rapid sequence of images using only one lens, allowed several minutes of action to be captured and stored on a single compact reel of flm. Some early flms were made to be viewed by one person at a time through a "peep show" device such as the Kinetoscope and the mutoscope. Others were intended for a projector, mechanically similar to the camera and sometimes actually the same machine, which was used to shine an intense light through the processed and printed flm and into a projection lens so that these "moving pictures" could be shown tremendously enlarged on a screen for viewing by an entire audience. Te frst kinetoscope flm shown in public exhibition was Blacksmith Scene, produced by Edison Manufacturing Company in 1893. Te following year the company would begin Edison Studios, which became an early leader in the flm industry with notable early shorts including Te Kiss, and would go on to produce close to 1,200 flms.

Te frst public screenings of flms at which admission was charged were made in 1895 by the American Woodville Latham and his sons, using flms produced by their company, and by the – arguably better known – French brothers Auguste and Louis Lumière with ten of their own productions.[citation needed] Private screenings had preceded these by several months, with Latham's slightly predating the Lumière brothers'. Another opinion is that the frst public exhibition of projected motion pictures in America was at Brooklyn Institute in New York City 9 May 1893.

Te earliest flms were simply one static shot that showed an event or action with no editing or other cinematic techniques. Around the turn of the 20th century, flms started stringing several scenes together to tell a story. Te scenes were later broken up into multiple shots photographed from diﬀerent distances and angles. Other techniques such as camera movement were developed as eﬀective ways to tell a story with flm. Until sound flm became commercially practical in the late 1920s, motion pictures were a purely visual art, but these innovative silent flms had gained a hold on the public imagination. Rather than leave audiences with only the noise of the projector as an accompaniment, theater owners hired a pianist or organist or, in large urban theaters, a full orchestra to play music that ft the mood of the flm at any given moment. By the early 1920s, most flms came with a prepared list of sheet music to be used for this purpose, and complete flm scores were composed for major productions.

Te rise of European cinema was interrupted by the outbreak of World War I, while the flm industry in the United States fourished with the rise of Hollywood, typifed most prominently by the innovative work of D. W. Griﬃth in Te Birth of a Nation (1915) and Intolerance (1916). However, in the 1920s, European flmmakers such as Sergei Eisenstein, F. W. Murnau and Fritz Lang, in many ways inspired by the meteoric wartime progress of flm through Griﬃth, along with the contributions of Charles Chaplin, Buster Keaton and others, quickly caught up with American flm-making and continued to further advance the medium.

In the 1920s, the development of electronic sound recording technologies made it practical to incorporate a soundtrack of speech, music and sound eﬀects synchronized with the action on the screen. Te resulting sound flms were initially distinguished from the usual silent "moving pictures" or "movies" by calling them "talking pictures" or "talkies."Te revolution they wrought was swift. By 1930, silent flm was practically extinct in the US and already being referred to as "the old medium."

Another major technological development was the introduction of "natural color," which meant color that was photographically recorded from nature rather than added to black-and-white prints by hand-coloring, stencil-coloring or other arbitrary procedures, although the earliest processes typically yielded colors which were far from "natural" in appearance. While the advent of sound flms quickly made silent flms and theater musicians obsolete, color replaced black- and-white much more gradually. Te pivotal innovation was the introduction of the three-strip version of the Technicolor process, frst used for animated cartoons in 1932, then also for live-action short flms and isolated sequences in a few feature flms, then for an entire feature flm, Becky Sharp, in 1935. Te expense of the process was daunting, but favorable public response in the form of increased box oﬃce receipts usually justifed the added cost. Te number of flms made in color slowly increased year after year.

324 became the rule rather than the exception. Some important mainstream Hollywood flms were still being made in black-and- white as late as the mid-1960s, but they marked the end of an era. Color television receivers had been available in the US since the mid-1950s, but at frst, they were very expensive and few broadcasts were in color. During the 1960s, prices gradually came down, color broadcasts became common, and sales boomed. Te overwhelming public verdict in favor of color was clear. After the fnal furry of black-and-white flms had been released in mid-decade, all Hollywood studio productions were flmed in color, with rare exceptions reluctantly made only at the insistence of "star" directors such as Peter Bogdanovich and Martin Scorsese.

Te decades following the decline of the studio system in the 1960s saw changes in the production and style of flm. Various New Wave movements (including the French New Wave, Indian New Wave, Japanese New Wave, and New Hollywood) and the rise of flm-school-educated independent flmmakers contributed to the changes the medium experienced in the latter half of the 20th century.[citation needed] Digital technology has been the driving force for change throughout the 1990s and into the 2000s. Digital 3D projection largely replaced earlier problem-prone 3D flm systems and has become popular in the early 2010s.

"Film theory" seeks to develop concise and systematic concepts that apply to the study of flm as art. Te concept of flm as an art-form began with Ricciotto Canudo's Te Birth of the Sixth Art. Formalist flm theory, led by Rudolf Arnheim, Béla Balázs, and Siegfried Kracauer, emphasized how flm diﬀered from reality and thus could be considered a valid fne art. André Bazin reacted against this theory by arguing that flm's artistic essence lay in its ability to mechanically reproduce reality, not in its diﬀerences from reality, and this gave rise to realist theory. More recent analysis spurred by Jacques Lacan's psychoanalysis and Ferdinand de Saussure's semiotics among other things has given rise to psychoanalytic flm theory, structuralist flm theory, feminist flm theory, and others. On the other hand, critics from the analytical philosophy tradition, infuenced by Wittgenstein, try to clarify misconceptions used in theoretical studies and produce analysis of a flm's vocabulary and its link to a form of life.

Film is considered to have its own language. James Monaco wrote a classic text on flm theory, titled "How to Read a Film," that addresses this. Director Ingmar Bergman famously said, "Andrei Tarkovsky for me is the greatest director, the one who invented a new language, true to the nature of flm, as it captures life as a refection, life as a dream." An example of the language is a sequence of back and forth images of one speaking actor's left profle, followed by another speaking actor's right profle, then a repetition of this, which is a language understood by the audience to indicate a conversation. Tis describes another theory of flm, the 180-degree rule, as a visual story-telling device with an ability to place a viewer in a context of being psychologically present through the use of visual composition and editing. Te "Hollywood style" includes this narrative theory, due to the overwhelming practice of the rule by movie studios based in Hollywood, California, during flm's classical era. Another example of cinematic language is having a shot that zooms in on the forehead of an actor with an expression of silent refection that cuts to a shot of a younger actor who vaguely resembles the frst actor, indicating that the frst person is remembering a past self, an edit of compositions that causes a time transition.

Montage is the technique by which separate pieces of flm are selected, edited, and then pieced together to make a new section of flm. A scene could show a man going into battle, with fashbacks to his youth and to his home-life and with added special effects, placed into the flm after flming is complete. As these were all flmed separately, and perhaps with different actors, the fnal version is called a montage. Directors developed a theory of montage, beginning with Eisenstein and the complex juxtaposition of images in his flm Battleship Potemkin. Incorporation of musical and visual counterpoint, and scene development through mise en scene, editing, and effects has led to more complex techniques comparable to those used in opera and ballet.

Film criticism is the analysis and evaluation of flms. In general, these works can be divided into two categories: academic criticism by flm scholars and journalistic flm criticism that appears regularly in newspapers and other media. Film critics working for newspapers, magazines, and broadcast media mainly review new releases. Normally they only see any given flm once and have only a day or two to formulate their opinions. Despite this, critics have an important impact on the audience response and attendance at flms, especially those of certain genres. Mass marketed action, horror, and comedy flms tend not to be greatly aﬀected by a critic's overall judgment of a flm. Te plot summary and description of a flm and the assessment of the director's and screenwriters' work that makes up the majority of most flm reviews can still have an important impact on whether people decide to see a flm. For prestige flms such as most dramas and art flms, the infuence of reviews is important. Poor reviews from leading critics at major papers and magazines will often reduce audience interest and attendance.

325 reactions can have considerable infuence. Other observers note that positive flm reviews have been shown to spark interest in little-known flms. Conversely, there have been several flms in which flm companies have so little confdence that they refuse to give reviewers an advanced viewing to avoid widespread panning of the flm. However, this usually backfres, as reviewers are wise to the tactic and warn the public that the flm may not be worth seeing and the flms often do poorly as a result. Journalist flm critics are sometimes called flm reviewers. Critics who take a more academic approach to flms, through publishing in flm journals and writing books about flms using flm theory or flm studies approaches, study how flm and flming techniques work, and what eﬀect they have on people. Rather than having their reviews published in newspapers or appearing on television, their articles are published in scholarly journals or up-market magazines. Tey also tend to be aﬃliated with colleges or universities as professors or instructors.

Babelsberg Studio near Berlin gate with pedestrian island: Te Babelsberg Studio near Berlin was the frst large-scale flm studio in the world (founded 1912) and the forerunner to Hollywood. It still produces global blockbusters every year. Te making and showing of motion pictures became a source of proft almost as soon as the process was invented. Upon seeing how successful their new invention, and its product, was in their native France, the Lumières quickly set about touring the Continent to exhibit the frst flms privately to royalty and publicly to the masses. In each country, they would normally add new, local scenes to their catalogue and, quickly enough, found local entrepreneurs in the various countries of Europe to buy their equipment and photograph, export, import, and screen additional product commercially. Te Oberammergau Passion Play of 1898[citation needed] was the frst commercial motion picture ever produced. Other pictures soon followed, and motion pictures became a separate industry that overshadowed the vaudeville world. Dedicated theaters and companies formed specifcally to produce and distribute flms, while motion picture actors became major celebrities and commanded huge fees for their performances. By 1917 Charlie Chaplin had a contract that called for an annual salary of one million dollars. From 1931 to 1956, flm was also the only image storage and playback system for television programming until the introduction of videotape recorders.

In the United States, much of the flm industry is centered around Hollywood, California. Other regional centers exist in many parts of the world, such as Mumbai-centered Bollywood, the Indian flm industry's Hindi cinema which produces the largest number of flms in the world. Tough the expense involved in making flms has led cinema production to concentrate under the auspices of movie studios, recent advances in aﬀordable flm making equipment have allowed independent flm productions to fourish.

Proft is a key force in the industry, due to the costly and risky nature of flmmaking; many flms have large cost overruns, an example being Kevin Costner's Waterworld. Yet many flmmakers strive to create works of lasting social signifcance. Te Academy Awards (also known as "the Oscars") are the most prominent flm awards in the United States, providing recognition each year to flms, based on their artistic merits. Tere is also a large industry for educational and instructional flms made in lieu of or in addition to lectures and texts. Revenue in the industry is sometimes volatile due to the reliance on blockbuster flms released in movie theaters. Te rise of alternative home entertainment has raised questions about the future of the cinema industry, and Hollywood employment has become less reliable, particularly for medium and low-budget flms.

Derivative academic felds of study may both interact with and develop independently of flmmaking, as in flm theory and analysis. Fields of academic study have been created that are derivative or dependent on the existence of flm, such as flm criticism, flm history, divisions of flm propaganda in authoritarian governments, or psychological on subliminal eﬀects (e.g., of a fashing soda can during a screening). Tese felds may further create derivative felds, such as a movie review section in a newspaper or a television guide. Sub-industries can spin oﬀ from flm, such as popcorn makers, and flm-related toys (e.g., Star Wars fgures). Sub-industries of pre-existing industries may deal specifcally with flm, such as product placement and other advertising within flms.

Te terminology used for describing motion pictures varies considerably between British and American English. In British usage, the name of the medium is "flm". Te word "movie" is understood but seldom used. Additionally, "the pictures" (plural) is used semi-frequently to refer to the place where movies are exhibited, while in American English this may be called "the movies", but it is becoming outdated. In other countries, the place where movies are exhibited may be called a cinema or movie theatre. By contrast, in the United States, "movie" is the predominant form. Although the words "flm" and "movie" are sometimes used interchangeably, "flm" is more often used when considering artistic, theoretical, or technical aspects. Te term "movies" more often refers to entertainment or commercial aspects, as where to go for fun evening on a date. For example, a book titled "How to Understand a Film" would probably be about the aesthetics or theory of flm, while a book entitled "Let's Go to the Movies" would probably be about the history of entertaining movies and blockbusters.

326 reproduction based on such is called a "transfer." After the advent of theatrical flm as an industry, the television industry began using videotape as a recording medium. For many decades, tape was solely an analog medium onto which moving images could be either recorded or transferred. "Film" and "flming" refer to the photochemical medium that chemically records a visual image and the act of recording respectively. However, the act of shooting images with other visual media, such as with a digital camera, is still called "flming" and the resulting works often called "flms" as interchangeable to "movies," despite not being shot on flm. "Silent flms" need not be utterly silent, but are flms and movies without an audible dialogue, including those that have a musical accompaniment. Te word, "Talkies," refers to the earliest sound flms created to have audible dialogue recorded for playback along with the flm, regardless of a musical accompaniment. "Cinema" either broadly encompasses both flms and movies, or it is roughly synonymous with flm and theatrical exhibition, and both are capitalized when referring to a category of art. Te "silver screen" refers to the projection screen used to exhibit flms and, by extension, is also used as a metonym for the entire flm industry.

"Widescreen" refers to a larger width to height in the frame, compared to earlier historic aspect ratios. A "feature-length flm", or "feature flm", is of a conventional full length, usually 60 minutes or more, and can commercially stand by itself without other flms in a ticketed screening. A "short" is a flm that is not as long as a feature-length flm, often screened with other shorts, or preceding a feature-length flm. An "independent" is a flm made outside the conventional flm industry.

In U.S. usage, one talks of a "screening" or "projection" of a movie or video on a screen at a public or private "theater." In British English, a "flm showing" happens at a cinema (never a "theatre", which is a different medium and place altogether). A cinema usually refers to an arena designed specifcally to exhibit flms, where the screen is affixed to a wall, while a theater usually refers to a place where live, non-recorded action or combination thereof occurs from a podium or other type of stage, including the amphitheater. Teaters can still screen movies in them, though the theater would be retroftted to do so. One might propose "going to the cinema" when referring to the activity, or sometimes "to the pictures" in British English, whereas the U.S. expression is usually "going to the movies." A cinema usually shows a mass-marketed movie using a front- projection screen process with either a flm projector or, more recently, with a digital projector. But, cinemas may also show theatrical movies from their home video transfers that include Blu-ray Disc, DVD, and videocassette when they possess sufficient projection quality or based upon need, such as movies that exist only in their transferred state, which may be due to the loss or deterioration of the flm master and prints from which the movie originally existed. Due to the advent of digital flm production and distribution, physical flm might be absent entirely. A "double feature" is a screening of two independently marketed, stand-alone feature flms. A "viewing" is a watching of a flm. "Sales" and "at the box office" refer to tickets sold at a theater, or more currently, rights sold for individual showings. A "release" is the distribution and often simultaneous screening of a flm. A "preview" is a screening in advance of the main release.

Any flm may also have a "sequel", which portrays events following those in the flm. Bride of Frankenstein is an early example. When there are more flms than one with the same characters, story arcs, or subject themes, these movies become a "series," such as the James Bond series. And, existing outside a specifc story timeline usually, does not exclude a flm from being part of a series. A flm that portrays events occurring earlier in a timeline with those in another flm, but is released after that flm, is sometimes called a "prequel," an example being Butch and Sundance: Te Early Days.

Te "credits," or "end credits," is a list that gives credit to the people involved in the production of a flm. Films from before the 1970s usually start a flm with credits, often ending with only a title card, saying "Te End" or some equivalent, often an equivalent that depends on the language of the production. From then onward, a flm's credits usually appear at the end of most flms. However, flms with credits that end a flm often repeat some credits at or near the start of a flm and therefore appear twice, such as that flm's acting leads, while less frequently some appearing near or at the beginning only appear there, not at the end, which often happens to the director's credit. Te credits appearing at or near the beginning of a flm are usually called "titles" or "beginning titles." A post-credits scene is a scene shown after the end of the credits. Ferris Bueller's Day Oﬀ has a post-credit scene in which Ferris tells the audience that the flm is over and they should go home.

A flm's "cast" refers to a collection of the actors and actresses who appear, or "star," in a flm. A star is an actor or actress, often a popular one, and in many cases, a celebrity who plays a central character in a flm. Occasionally the word can also be used to refer to the fame of other members of the crew, such as a director or other personality, such as Martin Scorsese. A "crew" is usually interpreted as the people involved in a flm's physical construction outside cast participation, and it could include directors, flm editors, photographers, grips, gaﬀers, set decorators, prop masters, and costume designers. A person can both be part of a flm's cast and crew, such as Woody Allen, who directed and starred in Take the Money and Run.

A "flm goer," "movie goer," or "flm buﬀ" is a person who likes or often attends flms and movies, and any of these, though more often the latter, could also see oneself as a student to flms and movies or the flmic process. Intense interest in flms, flm theory, and flm criticism, is known as cinephilia, or cinéaste in French.

327 A preview performance refers to a showing of a flm to a select audience, usually for the purposes of corporate promotions, before the public flm premiere itself. Previews are sometimes used to judge audience reaction, which if unexpectedly negative, may result in recutting or even reflming certain sections based on the audience response. One example of a flm that was changed after a negative response from the test screening is 1982's First Blood. After the test audience responded very negatively to the death of protagonist John Rambo, a Vietnam veteran, at the end of the flm, the company wrote and re-shot a new ending in which the character survives.

Trailers or previews are advertisements for flms that will be shown in 1 to 3 months at a cinema. Back in the early days of cinema, with theaters that had only one or two screens, only certain trailers were shown for the flms that were going to be shown there. Later, when theaters added more screens or new theaters were built with a lot of screens, all diﬀerent trailers were shown even if they weren't going to play that flm in that theater. Film studios realized that the more trailers that were shown (even if it wasn't going to be shown in that particular theater) the more patrons would go to a diﬀerent theater to see the flm when it came out. Te term "trailer" comes from their having originally been shown at the end of a flm program. Tat practice did not last long because patrons tended to leave the theater after the flms ended, but the name has stuck. Trailers are now shown before the flm (or the "A flm" in a double feature program) begins. Film trailers are also common on DVDs and Blu-ray Discs, as well as on the Internet and mobile devices. Trailers are created to be engaging and interesting for viewers. As a result, in the Internet era, viewers often seek out trailers to watch them. Of the ten billion videos watched online annually in 2008, flm trailers ranked third, after news and user-created videos. Teasers are a much shorter preview or advertisement that lasts only 10 to 30 seconds. Teasers are used to get patrons excited about a flm coming out in the next six to twelve months. Teasers may be produced even before the flm production is completed.

Film is used for a range of goals, including education and propaganda. When the purpose is primarily educational, a flm is called an "educational flm". Examples are recordings of academic lectures and experiments, or a flm based on a classic novel. Film may be propaganda, in whole or in part, such as the flms made by Leni Riefenstahl in Nazi Germany, US war flm trailers during World War II, or artistic flms made under Stalin by Eisenstein. Tey may also be works of political protest, as in the flms of Andrzej Wajda, or more subtly, the flms of Andrei Tarkovsky. Te same flm may be considered educational by some, and propaganda by others as the categorization of a flm can be subjective.

At its core, the means to produce a flm depend on the content the flmmaker wishes to show, and the apparatus for displaying it: the zoetrope merely requires a series of images on a strip of paper. Film production can, therefore, take as little as one person with a camera (or even without a camera, as in Stan Brakhage's 1963 flm Mothlight), or thousands of actors, extras, and crew members for a live-action, feature-length epic.

Te necessary steps for almost any flm can be boiled down to conception, planning, execution, revision, and distribution. Te more involved the production, the more signifcant each of the steps becomes. In a typical production cycle of a Hollywood-style flm, these main stages are defned as:

Tis production cycle usually takes three years. Te frst year is taken up with development. Te second year comprises preproduction and production. Te third year, post-production and distribution. Te bigger the production, the more resources it takes, and the more important fnancing becomes; most feature flms are artistic works from the creators' perspective (e.g., flm director, cinematographer, screenwriter) and for-proft business entities for the production companies A flm crew is a group of people hired by a flm company, employed during the "production" or "photography" phase, for the purpose of producing a flm or motion picture. Crew is distinguished from cast, who are the actors who appear in front of the camera or provide voices for characters in the flm. Te crew interacts with but is also distinct from the production staff, consisting of producers, managers, company representatives, their assistants, and those whose primary responsibility falls in pre-production or post-production phases, such as screenwriters and flm editors. Communication between production and crew generally passes through the director and his/her staff of assistants. Medium-to-large crews are generally divided into departments with well-defned hierarchies and standards for interaction and cooperation between the departments. Other than acting, the crew handles everything in the photography phase: props and costumes, shooting, sound, electrics (i.e., lights), sets, and production special effects. Caterers (known in the flm industry as "craft services") are usually not considered part of the crew.

328 frames per second were chosen because it was the slowest (and thus cheapest) speed which allowed for suﬃcient sound quality.[citation needed] Improvements since the late 19th century include the mechanization of cameras – allowing them to record at a consistent speed, quiet camera design – allowing sound recorded on-set to be usable without requiring large "blimps" to encase the camera, the invention of more sophisticated flmstocks and lenses, allowing directors to flm in increasingly dim conditions, and the development of synchronized sound, allowing sound to be recorded at exactly the same speed as its corresponding action. Te soundtrack can be recorded separately from shooting the flm, but for live-action pictures, many parts of the soundtrack are usually recorded simultaneously.

As a medium, flm is not limited to motion pictures, since the technology developed as the basis for photography. It can be used to present a progressive sequence of still images in the form of a slideshow. Film has also been incorporated into multimedia presentations and often has importance as primary historical documentation. However, historic flms have problems in terms of preservation and storage, and the motion picture industry is exploring many alternatives. Most flms on cellulose nitrate base have been copied onto modern safety flms. Some studios save color flms through the use of separation masters: three B&W negatives each exposed through red, green, or blue flters (essentially a reverse of the Technicolor process). Digital methods have also been used to restore flms, although their continued obsolescence cycle makes them (as of 2006) a poor choice for long-term preservation. Film preservation of decaying flm stock is a matter of concern to both flm historians and archivists and to companies interested in preserving their existing products in order to make them available to future generations (and thereby increase revenue). Preservation is generally a higher concern for nitrate and single-strip color flms, due to their high decay rates; black-and-white flms on safety bases and color flms preserved on Technicolor imbibition prints tend to keep up much better, assuming proper handling and storage.

Some flms in recent decades have been recorded using analog video technology similar to that used in television production. Modern digital video cameras and digital projectors are gaining ground as well. Tese approaches are preferred by some flmmakers, especially because footage shot with digital cinema can be evaluated and edited with non-linear editing systems (NLE) without waiting for the flm stock to be processed. Te migration was gradual, and as of 2005, most major motion pictures were still shot on flm. Te Lumière Brothers were the frst flmmakers; as such, they made their flms as independents, without support from a studio, as at that time the major flm studios did not exist. Independent flmmaking often takes place outside Hollywood, or other major studio systems. An independent flm (or indie flm) is a flm initially produced without fnancing or distribution from a major flm studio. Creative, business and technological reasons have all contributed to the growth of the indie flm scene in the late 20th and early 21st century. On the business side, the costs of big-budget studio flms also lead to conservative choices in cast and crew. Tere is a trend in Hollywood towards co-fnancing (over two-thirds of the flms put out by Warner Bros. in 2000 were joint ventures, up from 10% in 1987). A hopeful director is almost never given the opportunity to get a job on a big-budget studio flm unless he or she has signifcant industry experience in flm or television. Also, the studios rarely produce flms with unknown actors, particularly in lead roles.

Before the advent of digital alternatives, the cost of professional flm equipment and stock was also a hurdle to being able to produce, direct, or star in a traditional studio flm. But the advent of consumer camcorders in 1985, and more importantly, the arrival of high-resolution digital video in the early 1990s, have lowered the technology barrier to flm production signifcantly. Both production and post-production costs have been signifcantly lowered; in the 2000s, the hardware and software for post-production can be installed in a commodity-based personal computer. Technologies such as DVDs, FireWire connections and a wide variety of professional and consumer-grade video editing software make flm-making relatively aﬀordable.

Since the introduction of digital video DV technology, the means of production have become more democratized. Filmmakers can conceivably shoot a flm with a digital video camera and edit the flm, create and edit the sound and music, and mix the fnal cut on a high-end home computer. However, while the means of production may be democratized, fnancing, distribution, and marketing remain diﬃcult to accomplish outside the traditional system. Most independent flmmakers rely on flm festivals to get their flms noticed and sold for distribution. Te arrival of internet-based video websites such as YouTube and Veoh has further changed the flmmaking landscape, enabling indie flmmakers to make their flms available to the public.

An open content flm is much like an independent flm, but it is produced through open collaborations; its source material is available under a license which is permissive enough to allow other parties to create fan fction or derivative works, than a traditional copyright. Like independent flmmaking, open source flmmaking takes place outside Hollywood, or other major studio systems.

A fan flm is a flm or video inspired by a flm, television program, comic book or a similar source, created by fans rather than by the source's copyright holders or creators. Fan flmmakers have traditionally been amateurs, but some of the most notable flms have actually been produced by professional flmmakers as flm school class projects or as demonstration reels.

329 Fan flms vary tremendously in length, from short faux-teaser trailers for non-existent motion pictures to rarer full-length motion pictures.

Film distribution is the process through which a flm is made available for viewing by an audience. Tis is normally the task of a professional flm distributor, who would determine the marketing strategy of the flm, the media by which a flm is to be exhibited or made available for viewing, and may set the release date and other matters. Te flm may be exhibited directly to the public either through a movie theater (historically the main way flms were distributed) or television for personal home viewing (including on DVD-Video or Blu-ray Disc, video-on-demand, online downloading, television programs through broadcast syndication etc.). Other ways of distributing a flm include rental or personal purchase of the flm in a variety of media and formats, such as VHS tape or DVD, or Internet downloading of streaming using a computer.

Animation is a technique in which each frame of a flm is produced individually, whether generated as a computer graphic, or by photographing a drawn image, or by repeatedly making small changes to a model unit (see claymation and stop motion), and then photographing the result with a special animation camera. When the frames are strung together and the resulting flm is viewed at a speed of 16 or more frames per second, there is an illusion of continuous movement (due to the phi phenomenon). Generating such a flm is very labor-intensive and tedious, though the development of computer animation has greatly sped up the process. Because animation is very time-consuming and often very expensive to produce, the majority of animation for TV and flms comes from professional animation studios. However, the feld of independent animation has existed at least since the 1950s, with animation being produced by independent studios (and sometimes by a single person). Several independent animation producers have gone on to enter the professional animation industry.

Limited animation is a way of increasing production and decreasing costs of animation by using "short cuts" in the animation process. Tis method was pioneered by UPA and popularized by Hanna-Barbera in the United States, and by Osamu Tezuka in Japan, and adapted by other studios as cartoons moved from movie theaters to television. Although most animation studios are now using digital technologies in their productions, there is a specifc style of animation that depends on flm. Camera-less animation, made famous by flm-makers like Norman McLaren, Len Lye, and Stan Brakhage, is painted and drawn directly onto pieces of flm, and then run through a projector.

Teatre

Teatre or theater s a collaborative form of fne art that uses live performers, typically actors or actresses, to present the experience of a real or imagined event before a live audience in a specifc place, often a stage. Te performers may communicate this experience to the audience through combinations of gesture, speech, song, music, and dance. Elements of art, such as painted scenery and stagecraft such as lighting are used to enhance the physicality, presence and immediacy of the experience. Te specifc place of the performance is also named by the word "theatre" as derived from the Ancient Greek θέατρον (théatron, "a place for viewing"), itself from θεάομαι (theáomai, "to see", "to watch", "to observe").

Modern Western theatre comes, in large measure, from ancient Greek drama, from which it borrows technical terminology, classifcation into genres, and many of its themes, stock characters, and plot elements. Teatre artist Patrice Pavis defnes theatricality, theatrical language, stage writing and the specifcity of theatre as synonymous expressions that diﬀerentiate theatre from the other performing arts, literature and the arts in general.

Modern theatre, broadly defned, includes performances of plays and musical theatre. Tere are connections between theatre and the art forms of ballet, opera (which uses staged, costumed performances with singing and orchestral accompaniment) and various other forms.

A depiction of actors playing the roles of a master (right) and his slave (left) in a Greek phlyax play, circa 350/340 BCE. Te city-state of Athens is where western theatre originated. It was part of a broader culture of theatricality and performance in classical Greece that included festivals, religious rituals, politics, law, athletics and gymnastics, music, poetry, weddings, funerals, and symposia.

Participation in the city-state's many festivals—and mandatory attendance at the City Dionysia as an audience member (or even as a participant in the theatrical productions) in particular—was an important part of citizenship. Civic participation also involved the evaluation of the rhetoric of orators evidenced in performances in the law-court or political assembly, both 330 of which were understood as analogous to the theatre and increasingly came to absorb its dramatic vocabulary. Te Greeks also developed the concepts of dramatic criticism and theatre architecture. Actors were either amateur or at best semi- professional. Te theatre of ancient Greece consisted of three types of drama: tragedy, comedy, and the satyr play.

Te origins of theatre in ancient Greece, according to Aristotle (384–322 BCE), the frst theoretician of theatre, are to be found in the festivals that honoured Dionysus. Te performances were given in semi-circular auditoria cut into hillsides, capable of seating 10,000–20,000 people. Te stage consisted of a dancing foor (orchestra), dressing room and scene- building area (skene). Since the words were the most important part, good acoustics and clear delivery were paramount. Te actors (always men) wore masks appropriate to the characters they represented, and each might play several parts.

Athenian tragedy—the oldest surviving form of tragedy—is a type of dance-drama that formed an important part of the theatrical culture of the city-state. Having emerged sometime during the 6th century BCE, it fowered during the 5th century BCE (from the end of which it began to spread throughout the Greek world), and continued to be popular until the beginning of the Hellenistic period.

No tragedies from the 6th century BCE and only 32 of the more than a thousand that were performed in during the 5th century BCE have survived.[14] We have complete texts extant by Aeschylus, Sophocles, and Euripides. Te origins of tragedy remain obscure, though by the 5th century BCE it was institutionalised in competitions (agon) held as part of festivities celebrating Dionysus (the god of wine and fertility). As contestants in the City Dionysia's competition (the most prestigious of the festivals to stage drama) playwrights were required to present a tetralogy of plays (though the individual works were not necessarily connected by story or theme), which usually consisted of three tragedies and one satyr play. Te performance of tragedies at the City Dionysia may have begun as early as 534 BCE; oﬃcial records (didaskaliai) begin from 501 BCE, when the satyr play was introduced.

Most Athenian tragedies dramatise events from Greek mythology, though Te Persians—which stages the Persian response to news of their military defeat at the Battle of Salamis in 480 BCE—is the notable exception in the surviving drama. When Aeschylus won frst prize for it at the City Dionysia in 472 BCE, he had been writing tragedies for more than 25 years, yet its tragic treatment of recent history is the earliest example of drama to survive. More than 130 years later, the philosopher Aristotle analysed 5th-century Athenian tragedy in the oldest surviving work of dramatic theory—his Poetics (c. 335 BCE).

Athenian comedy is conventionally divided into three periods, "Old Comedy", "Middle Comedy", and "New Comedy". Old Comedy survives today largely in the form of the eleven surviving plays of Aristophanes, while Middle Comedy is largely lost (preserved only in relatively short fragments in authors such as Athenaeus of Naucratis). New Comedy is known primarily from the substantial papyrus fragments of Menander. Aristotle defned comedy as a representation of laughable people that involves some kind of blunder or ugliness that does not cause pain or disaster.

In addition to the categories of comedy and tragedy at the City Dionysia, the festival also included the Satyr Play. Finding its origins in rural, agricultural rituals dedicated to Dionysus, the satyr play eventually found its way to Athens in its most well- known form. Satyr's themselves were tied to the god Dionysus as his loyal woodland companions, often engaging in drunken revelry and mischief at his side. Te satyr play itself was classifed as tragicomedy, erring on the side of the more modern burlesque traditions of the early twentieth century. Te plotlines of the plays were typically concerned with the dealings of the pantheon of Gods and their involvement in human aﬀairs, backed by the chorus of Satyrs. However, according to Webster, satyr actors did not always perform typical satyr actions and would break from the acting traditions assigned to the character type of a mythical forest creature.

Mosaic depicting masked actors in a play: two women consult a “witch" Western theatre developed and expanded considerably under the Romans. Te Roman historian Livy wrote that the Romans frst experienced theatre in the 4th century BCE, with a performance by Etruscan actors. Beacham argues that they had been familiar with "pre-theatrical practices" for some time before that recorded contact. Te theatre of ancient Rome was a thriving and diverse art form, ranging from festival performances of street theatre, nude dancing, and acrobatics, to the staging of Plautus's broadly appealing situation comedies, to the high-style, verbally elaborate tragedies of Seneca. Although Rome had a native tradition of performance, the Hellenization of Roman culture in the 3rd century BCE had a profound and energizing eﬀect on Roman theatre and encouraged the development of Latin literature of the highest quality for the stage. Te only surviving Roman tragedies, indeed the only plays of any kind from the Roman Empire, are ten dramas- nine of them pallilara- attributed to Lucuis Annaeus Seneca (4 b.c.-65 a.d.), the Corduba-born Stoic philosopher and tutor of Nero.

Te earliest-surviving fragments of Sanskrit drama date from the 1st century AD. Te wealth of archeological evidence from earlier periods oﬀers no indication of the existence of a tradition of theatre. Te ancient Vedas (hymns from between 1500 and 1000 BC that are among the earliest examples of literature in the world) contain no hint of it (although a small number are composed in a form of dialogue) and the rituals of the Vedic period do not appear to have developed into theatre. Te

331 Mahābhāṣya by Patañjali contains the earliest reference to what may have been the seeds of Sanskrit drama. Tis treatise on grammar from 140 BC provides a feasible date for the beginnings of theatre in India.

Te major source of evidence for Sanskrit theatre is A Treatise on Teatre (Nātyaśāstra), a compendium whose date of composition is uncertain (estimates range from 200 BC to 200 AD) and whose authorship is attributed to Bharata Muni. Te Treatise is the most complete work of dramaturgy in the ancient world. It addresses acting, dance, music, dramatic construction, architecture, costuming, make-up, props, the organisation of companies, the audience, competitions, and oﬀers a mythological account of the origin of theatre. In doing so, it provides indications about the nature of actual theatrical practices. Sanskrit theatre was performed on sacred ground by priests who had been trained in the necessary skills (dance, music, and recitation) in a [hereditary process]. Its aim was both to educate and to entertain.

Under the patronage of royal courts, performers belonged to professional companies that were directed by a stage manager (sutradhara), who may also have acted.[29] Tis task was thought of as being analogous to that of a puppeteer—the literal meaning of "sutradhara" is "holder of the strings or threads". Te performers were trained rigorously in vocal and physical technique.[30] Tere were no prohibitions against female performers; companies were all-male, all-female, and of mixed gender. Certain sentiments were considered inappropriate for men to enact, however, and were thought better suited to women. Some performers played characters their own age, while others played ages diﬀerent from their own (whether younger or older). Of all the elements of theatre, the Treatise gives most attention to acting (abhinaya), which consists of two styles: realistic (lokadharmi) and conventional (natyadharmi), though the major focus is on the latter.

Its drama is regarded as the highest achievement of Sanskrit literature. It utilised stock characters, such as the hero (nayaka), heroine (nayika), or clown (vidusaka). Actors may have specialised in a particular type. Kālidāsa in the 1st century BCE, is arguably considered to be ancient India's greatest Sanskrit dramatist. Tree famous romantic plays written by Kālidāsa are the Mālavikāgnimitram (Mālavikā and Agnimitra), Vikramuurvashiiya (Pertaining to Vikrama and Urvashi), and Abhijñānaśākuntala (Te Recognition of Shakuntala). Te last was inspired by a story in the Mahabharata and is the most famous. It was the frst to be translated into English and German. Śakuntalā (in English translation) infuenced Goethe's Faust (1808–1832).

Te next great Indian dramatist was Bhavabhuti (c. 7th century AD). He is said to have written the following three plays: Malati-Madhava, Mahaviracharita and Uttar Ramacharita. Among these three, the last two cover between them the entire epic of Ramayana. Te powerful Indian emperor Harsha (606–648) is credited with having written three plays: the comedy Ratnavali, Priyadarsika, and the Buddhist drama Nagananda.

Tere are references to theatrical entertainments in China as early as the Shang Dynasty; they often involved happiness, mimes, and acrobatic displays.Te Tang Dynasty is sometimes known as "Te Age of 1000 Entertainments". During this era, Ming Huang formed an acting school known as Te Pear Garden to produce a form of drama that was primarily musical. Tat is why actors are commonly called "Children of the Pear Garden." During the Dynasty of Empress Ling, shadow puppetry frst emerged as a recognized form of theatre in China. Tere were two distinct forms of shadow puppetry, Pekingese (northern) and Cantonese (southern). Te two styles were diﬀerentiated by the method of making the puppets and the positioning of the rods on the puppets, as opposed to the type of play performed by the puppets. Both styles generally performed plays depicting great adventure and fantasy, rarely was this very stylized form of theatre used for political propaganda.

Cantonese shadow puppets were the larger of the two. Tey were built using thick leather which created more substantial shadows. Symbolic color was also very prevalent; a black face represented honesty, a red one bravery. Te rods used to control Cantonese puppets were attached perpendicular to the puppets’ heads. Tus, they were not seen by the audience when the shadow was created. Pekingese puppets were more delicate and smaller. Tey were created out of thin, translucent leather (usually taken from the belly of a donkey).Tey were painted with vibrant paints, thus they cast a very colorful shadow. Te thin rods which controlled their movements were attached to a leather collar at the neck of the puppet. Te rods ran parallel to the bodies of the puppet then turned at a ninety degree angle to connect to the neck. While these rods were visible when the shadow was cast, they laid outside the shadow of the puppet; thus they did not interfere with the appearance of the fgure. Te rods attached at the necks to facilitate the use of multiple heads with one body. When the heads were not being used, they were stored in a muslin book or fabric lined box. Te heads were always removed at night. Tis was in keeping with the old superstition that if left intact, the puppets would come to life at night. Some puppeteers went so far as to store the heads in one book and the bodies in another, to further reduce the possibility of reanimating puppets. Shadow puppetry is said to have reached its highest point of artistic development in the eleventh century before becoming a tool of the government.

In the Song Dynasty, there were many popular plays involving acrobatics and music. Tese developed in the Yuan Dynasty into a more sophisticated form known as zaju, with a four- or fve-act structure. Yuan drama spread across China and 332 diversifed into numerous regional forms, the best known of which is Beijing Opera[citation needed], which is still popular today.

Xiangsheng is a certain traditional Chinese comedic performance in the forms of monologue or dialogue.

Teatre took on many alternate forms in the West between the 15th and 19th centuries, including commedia dell'arte and melodrama. Te general trend was away from the poetic drama of the Greeks and the Renaissance and toward a more naturalistic prose style of dialogue, especially following the Industrial Revolution.

Teatre took a big pause during 1642 and 1660 in England because of the Puritan Interregnum. Teatre was seen as something sinful and the Puritans tried very hard to drive it out of their society. Tis stagnant period ended once Charles II came back to the throne in 1660 in the Restoration. Teatre (among other arts) exploded, with infuence from French culture, since Charles had been exiled in France in the years previous to his reign.

One of the big changes was the new theatre house. Instead of the type of the Elizabethan era, such as the Globe Teatre, round with no place for the actors to really prep for the next act and with no "theatre manners,” the theatre house became transformed into a place of refnement, with a stage in front and stadium seating facing it. Since seating was no longer all the way around the stage, it became prioritized – some seats were obviously better than others. Te king would have the best seat in the house: the very middle of the theatre, which got the widest view of the stage as well as the best way to see the point of view and vanishing point that the stage was constructed around. Philippe Jacques de Loutherbourg was one of the most infuential set designers of the time because of his use of foor space and scenery.

Because of the turmoil before this time, there was still some controversy about what should and should not be put on the stage. Jeremy Collier, a preacher, was one of the heads in this movement through his piece A Short View of the Immorality and Profaneness of the English Stage. Te beliefs in this paper were mainly held by non-theatre goers and the remainder of the Puritans and very religious of the time. Te main question was if seeing something immoral on stage aﬀects behavior in the lives of those who watch it, a controversy that is still playing out today.

Te eighteenth century also introduced women to the stage, which was considered inappropriate earlier. Tese women were regarded as celebrities (also a newer concept, thanks to ideas on individualism that arose in the wake of Renaissance Humanism), but on the other hand, it was still very new and revolutionary that they were on the stage, and some said they were unladylike, and looked down on them. Charles II did not like young men playing the parts of young women, so he asked that women play their own parts.[35] Because women were allowed on the stage, playwrights had more leeway with plot twists, like women dressing as men, and having narrow escapes from morally sticky situations as forms of comedy.

Comedies were full of the young and very much in vogue, with the storyline following their love lives: commonly a young roguish hero professing his love to the chaste and free minded heroine near the end of the play, much like Sheridan's Te School for Scandal. Many of the comedies were fashioned after the French tradition, mainly Molière, again hailing back to the French infuence brought back by the King and the Royals after their exile. Molière was one of the top comedic playwrights of the time, revolutionizing the way comedy was written and performed by combining Italian commedia dell'arte and neoclassical French comedy to create some of the longest lasting and most infuential satiric comedies. Tragedies were similarly victorious in their sense of righting political power, especially poignant because of the recent Restoration of the Crown. Tey were also imitations of French tragedy, although the French had a larger distinction between comedy and tragedy, whereas the English fudged the lines occasionally and put some comedic parts in their tragedies. Common forms of non-comedic plays were sentimental comedies as well as something that would later be called tragédie bourgeoise, or domestic tragedy – that is, the tragedy of common life – were more popular in England because they appealed more to English sensibilities.

While theatre troupes were formerly often travelling, the idea of the national theatre gained support in the 18th century, inspired by Ludvig Holberg. Te major promoter of the idea of the national theatre in Germany, and also of the Sturm und Drang poets, was Abel Seyler, the owner of the Hamburgische Entreprise and the Seyler Teatre Company.

Trough the 19th century, the popular theatrical forms of Romanticism, melodrama, Victorian burlesque and the well-made plays of Scribe and Sardou gave way to the problem plays of Naturalism and Realism; the farces of Feydeau; Wagner's operatic Gesamtkunstwerk; musical theatre (including Gilbert and Sullivan's operas); F. C. Burnand's, W. S. Gilbert's and Oscar Wilde's drawing-room comedies; Symbolism; proto-Expressionism in the late works of August Strindberg and Henrik Ibsen; and Edwardian musical comedy.

Tese trends continued through the 20th century in the realism of Stanislavski and Lee Strasberg, the political theatre of Erwin Piscator and Bertolt Brecht, the so-called Teatre of the Absurd of Samuel Beckett and Eugène Ionesco, American and

333 British musicals, the collective creations of companies of actors and directors such as Joan Littlewood's Teatre Workshop, experimental and postmodern theatre of Robert Wilson and Robert Lepage, the postcolonial theatre of August Wilson or Tomson Highway, and Augusto Boal's Teatre of the Oppressed.

Rakshasa or the demon as depicted in Yakshagana, a form of musical dance-drama from India Te frst form of Indian theatre was the Sanskrit theatre. It began after the development of Greek and Roman theatre and before the development of theatre in other parts of Asia. It emerged sometime between the 2nd century BCE and the 1st century CE and fourished between the 1st century CE and the 10th, which was a period of relative peace in the history of India during which hundreds of plays were written. Japanese forms of Kabuki, Nō, and Kyōgen developed in the 17th century CE. Teatre in the medieval Islamic world included puppet theatre (which included hand puppets, shadow plays and marionette productions) and live passion plays known as ta'ziya, where actors re-enact episodes from Muslim history. In particular, Shia Islamic plays revolved around the shaheed (martyrdom) of Ali's sons Hasan ibn Ali and Husayn ibn Ali. Secular plays were known as akhraja, recorded in medieval adab literature, though they were less common than puppetry and ta'ziya theatre.

Drama is the specifc mode of fction represented in performance. Te term comes from a Greek word meaning "action", which is derived from the verb δράω, dráō, "to do" or "to act". Te enactment of drama in theatre, performed by actors on a stage before an audience, presupposes collaborative modes of production and a collective form of reception. Te structure of dramatic texts, unlike other forms of literature, is directly infuenced by this collaborative production and collective reception. Te early modern tragedy Hamlet (1601) by Shakespeare and the classical Athenian tragedy Oedipus Rex (c. 429 BCE) by Sophocles are among the masterpieces of the art of drama. A modern example is Long Day's Journey into Night by Eugene O'Neill (1956).

Considered as a genre of poetry in general, the dramatic mode has been contrasted with the epic and the lyrical modes ever since Aristotle's Poetics (c. 335 BCE)—the earliest work of dramatic theory. Te use of "drama" in the narrow sense to designate a specifc type of play dates from the 19th century. Drama in this sense refers to a play that is neither a comedy nor a tragedy—for example, Zola's Térèse Raquin (1873) or Chekhov's Ivanov (1887). In Ancient Greece however, the word drama encompassed all theatrical plays, tragic, comic, or anything in between.

Drama is often combined with music and dance: the drama in opera is generally sung throughout; musicals generally include both spoken dialogue and songs; and some forms of drama have incidental music or musical accompaniment underscoring the dialogue (melodrama and Japanese Nō, for example). In certain periods of history (the ancient Roman and modern Romantic) some dramas have been written to be read rather than performed. In improvisation, the drama does not pre-exist the moment of performance; performers devise a dramatic script spontaneously before an audience.

Music and theatre have had a close relationship since ancient times—Athenian tragedy, for example, was a form of dance- drama that employed a chorus whose parts were sung (to the accompaniment of an aulos—an instrument comparable to the modern clarinet), as were some of the actors' responses and their 'solo songs' (monodies). Modern musical theatre is a form of theatre that also combines music, spoken dialogue, and dance. It emerged from comic opera (especially Gilbert and Sullivan), variety, vaudeville, and music hall genres of the late 19th and early 20th century. After the Edwardian musical comedy that began in the 1890s, the Princess Teatre musicals of the early 20th century, and comedies in the 1920s and 1930s (such as the works of Rodgers and Hammerstein), with Oklahoma! (1943), musicals moved in a more dramatic direction. Famous musicals over the subsequent decades included My Fair Lady (1956), West Side Story (1957), Te Fantasticks (1960), Hair (1967), A Chorus Line (1975), Les Misérables (1980), Into the Woods (1986), and Te Phantom of the Opera (1986),[56] as well as more contemporary hits including Rent (1994), Te Lion King (1997), Wicked (2003), and Hamilton (musical) (2015).

Musical theatre may be produced on an intimate scale Oﬀ-Broadway, in regional theatres, and elsewhere, but it often includes spectacle. For instance, Broadway and West End musicals often include lavish costumes and sets supported by multimillion-dollar budgets.

Teatre productions that use humour as a vehicle to tell a story qualify as comedies. Tis may include a modern farce such as Boeing Boeing or a classical play such as As You Like It. Teatre expressing bleak, controversial or taboo subject matter in a deliberately humorous way is referred to as black comedy. Black Comedy can have several genres like slapstick humour, dark and sarcastic comedy.

Tragedy, then, is an imitation of an action that is serious, complete, and of a certain magnitude: in language embellished with each kind of artistic ornament, the several kinds being found in separate parts of the play; in the form of action, not of narrative; through pity and fear eﬀecting the proper purgation of these emotions.

334 Aristotle's phrase "several kinds being found in separate parts of the play" is a reference to the structural origins of drama. In it the spoken parts were written in the Attic dialect whereas the choral (recited or sung) ones in the Doric dialect, these discrepancies refecting the diﬀering religious origins and poetic metres of the parts that were fused into a new entity, the theatrical drama.

Tragedy refers to a specifc tradition of drama that has played a unique and important role historically in the self-defnition of Western civilisation. Tat tradition has been multiple and discontinuous, yet the term has often been used to invoke a powerful eﬀect of cultural identity and historical continuity—"the Greeks and the Elizabethans, in one cultural form; Hellenes and Christians, in a common activity," as Raymond Williams puts it. From its obscure origins in the theatres of Athens 2,500 years ago, from which there survives only a fraction of the work of Aeschylus, Sophocles and Euripides, through its singular articulations in the works of Shakespeare, Lope de Vega, Racine, and Schiller, to the more recent naturalistic tragedy of Strindberg, Beckett's modernist meditations on death, loss and suﬀering, and Müller's postmodernist reworkings of the tragic canon, tragedy has remained an important site of cultural experimentation, negotiation, struggle, and change. In the wake of Aristotle's Poetics (335 BCE), tragedy has been used to make genre distinctions, whether at the scale of poetry in general (where the tragic divides against epic and lyric) or at the scale of the drama (where tragedy is opposed to comedy). In the modern era, tragedy has also been defned against drama, melodrama, the tragicomic, and epic theatre.

Improvisation has been a consistent feature of theatre, with the Commedia dell'arte in the sixteenth century being recognised as the frst improvisation form. Popularized by Nobel Prize Winner Dario Fo and troupes such as the Upright Citizens Brigade improvisational theatre continues to evolve with many diﬀerent streams and philosophies. Keith Johnstone and Viola Spolin are recognized as the frst teachers of improvisation in modern times, with Johnstone exploring improvisation as an alternative to scripted theatre and Spolin and her successors exploring improvisation principally as a tool for developing dramatic work or skills or as a form for situational comedy. Spolin also became interested in how the process of learning improvisation was applicable to the development of human potential. Spolin's son, Paul Sills popularized improvisational theatre as a theatrical art form when he founded. as its frst director, the Second City in Chicago.

Dramatic theory: Having been an important part of human culture for more than 2,500 years, theatre has evolved a wide range of diﬀerent theories and practices. Some are related to political or spiritual ideologies, while others are based purely on "artistic" concerns. Some processes focus on a story, some on theatre as event, and some on theatre as catalyst for social change. Te classical Greek philosopher Aristotle, in his seminal treatise, Poetics (c. 335 BCE) is the earliest-surviving example and its arguments have infuenced theories of theatre ever since. In it, he oﬀers an account of what he calls "poetry" (a term which in Greek literally means "making" and in this context includes drama—comedy, tragedy, and the satyr play—as well as lyric poetry, epic poetry, and the dithyramb). He examines its "frst principles" and identifes its genres and basic elements; his analysis of tragedy constitutes the core of the discussion. He argues that tragedy consists of six qualitative parts, which are (in order of importance) mythos or "plot", ethos or "character", dianoia or "thought", lexis or "diction", melos or "song", and opsis or "spectacle".[65] "Although Aristotle's Poetics is universally acknowledged in the Western critical tradition," Marvin Carlson explains, "almost every detail about his seminal work has aroused divergent opinions."[66] Important theatre practitioners of the 20th century include Konstantin Stanislavski, Vsevolod Meyerhold, Jacques Copeau, Edward Gordon Craig, Bertolt Brecht, Antonin Artaud, Joan Littlewood, Peter Brook, Jerzy Grotowski, Augusto Boal, Eugenio Barba, Dario Fo, Viola Spolin, Keith Johnstone and Robert Wilson (director).

Stanislavski treated the theatre as an art-form that is autonomous from literature and one in which the playwright's contribution should be respected as that of only one of an ensemble of creative artists. His innovative contribution to modern acting theory has remained at the core of mainstream western performance training for much of the last century. Tat many of the precepts of his system of actor training seem to be common sense and self-evident testifes to its hegemonic success. Actors frequently employ his basic concepts without knowing they do so. Tanks to its promotion and elaboration by acting teachers who were former students and the many translations of his theoretical writings, Stanislavski's 'system' acquired an unprecedented ability to cross cultural boundaries and developed an international reach, dominating debates about acting in Europe and the United States. Many actors routinely equate his 'system' with the North American Method, although the latter's exclusively psychological techniques contrast sharply with Stanislavski's multivariant, holistic and psychophysical approach, which explores character and action both from the 'inside out' and the 'outside in' and treats the actor's mind and body as parts of a continuum.

Teatre presupposes collaborative modes of production and a collective form of reception. Te structure of dramatic texts, unlike other forms of literature, is directly infuenced by this collaborative production and collective reception.[46] Te production of plays usually involves contributions from a playwright, director, a cast of actors, and a technical production team that includes a scenic or set designer, lighting designer, costume designer, sound designer, stage manager, production manager and technical director. Depending on the production, this team may also include a composer, dramaturg, video designer or fght director.

335 Stagecraft is a generic term referring to the technical aspects of theatrical, flm, and video production. It includes, but is not limited to, constructing and rigging scenery, hanging and focusing of lighting, design and procurement of costumes, makeup, procurement of props, stage management, and recording and mixing of sound. Stagecraft is distinct from the wider umbrella term of scenography. Considered a technical rather than an artistic feld, it relates primarily to the practical implementation of a designer's artistic vision.

In its most basic form, stagecraft is managed by a single person (often the stage manager of a smaller production) who arranges all scenery, costumes, lighting, and sound, and organizes the cast. At a more professional level, for example in modern Broadway houses, stagecraft is managed by hundreds of skilled carpenters, painters, electricians, stagehands, stitchers, wigmakers, and the like. Tis modern form of stagecraft is highly technical and specialized: it comprises many sub- disciplines and a vast trove of history and tradition. Te majority of stagecraft lies between these two extremes. Regional theatres and larger community theatres will generally have a technical director and a complement of designers, each of whom has a direct hand in their respective designs.

While most modern theatre companies rehearse one piece of theatre at a time, perform that piece for a set "run", retire the piece, and begin rehearsing a new show, repertory companies rehearse multiple shows at one time. Tese companies are able to perform these various pieces upon request and often perform works for years before retiring them. Most dance companies operate on this repertory system. Te Royal National Teatre in London performs on a repertory system.

Repertory theatre generally involves a group of similarly accomplished actors, and relies more on the reputation of the group than on an individual star actor. It also typically relies less on strict control by a director and less on adherence to theatrical conventions, since actors who have worked together in multiple productions can respond to each other without relying as much on convention or external direction.

In order to put on a piece of theatre, both a theatre company and a theatre venue are needed. When a theatre company is the sole company in residence at a theatre venue, this theatre (and its corresponding theatre company) are called a resident theatre or a producing theatre, because the venue produces its own work. Other theatre companies, as well as dance companies, who do not have their own theatre venue, perform at rental theatres or at presenting theatres. Both rental and presenting theatres have no full-time resident companies. Tey do, however, sometimes have one or more part-time resident companies, in addition to other independent partner companies who arrange to use the space when available. A rental theatre allows the independent companies to seek out the space, while a presenting theatre seeks out the independent companies to support their work by presenting them on their stage.

Some performance groups perform in non-theatrical spaces. Such performances can take place outside or inside, in a non- traditional performance space, and include street theatre, and site-specifc theatre. Non-traditional venues can be used to create more immersive or meaningful environments for audiences. Tey can sometimes be modifed more heavily than traditional theatre venues, or can accommodate diﬀerent kinds of equipment, lighting and sets.

A touring company is an independent theatre or dance company that travels, often internationally, being presented at a diﬀerent theatre in each city.

In a modern sense, comedy (from the Greek: κωμῳδία, kōmōidía) refers to any discourse or work generally intended to be humorous or amusing by inducing laughter, especially in theatre, television, flm, stand-up comedy, or any other medium of entertainment. Te origins of the term are found in Ancient Greece. In the Athenian democracy, the public opinion of voters was infuenced by the political satire performed by the comic poets at the theaters. Te theatrical genre of Greek comedy can be described as a dramatic performance which pits two groups or societies against each other in an amusing agon or confict. Northrop Frye depicted these two opposing sides as a "Society of Youth" and a "Society of the Old". A revised view characterizes the essential agon of comedy as a struggle between a relatively powerless youth and the societal conventions that pose obstacles to his hopes. In this struggle, the youth is understood to be constrained by his lack of social authority, and is left with little choice but to take recourse in ruses which engender very dramatic irony which provokes laughter.

Satire and political satire use comedy to portray persons or social institutions as ridiculous or corrupt, thus alienating their audience from the object of their humour. Parody subverts popular genres and forms, critiquing those forms without necessarily condemning them.

336 Film

A flm, also called a movie, motion picture, moving picture, or photoplay, is a series of still images that, when shown on a screen, create the illusion of moving images. Tis optical illusion causes the audience to perceive continuous motion between separate objects viewed in rapid succession. Te process of flmmaking is both an art and an industry. A flm is created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, and other visual eﬀects.

Te word "cinema", short for cinematography, is often used to refer to flmmaking and the flm industry, and to the art of flmmaking itself. Te contemporary defnition of cinema is the art of simulating experiences to communicate ideas, stories, perceptions, feelings, beauty or atmosphere by the means of recorded or programmed moving images along with other sensory stimulations.[1]

Films were originally recorded onto plastic flm through a photochemical process and then shown through a movie projector onto a large screen. Contemporary flms are now often fully digital through the entire process of production, distribution, and exhibition, while flms recorded in a photochemical form traditionally included an analogous optical soundtrack (a graphic recording of the spoken words, music and other sounds that accompany the images which runs along a portion of the flm exclusively reserved for it, and is not projected).

Films are cultural artifacts created by specifc cultures. Tey refect those cultures, and, in turn, aﬀect them. Film is considered to be an important art form, a source of popular entertainment, and a powerful medium for educating—or indoctrinating—citizens. Te visual basis of flm gives it a universal power of communication. Some flms have become popular worldwide attractions through the use of dubbing or subtitles to translate the dialog into other languages.

Te individual images that make up a flm are called frames. In the projection of traditional celluloid flms, a rotating shutter causes intervals of darkness as each frame, in turn, is moved into position to be projected, but the viewer does not notice the interruptions because of an eﬀect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after its source disappears. Te perception of motion is due to a psychological eﬀect called the phi phenomenon.

Te name "flm" originates from the fact that photographic flm (also called flm stock) has historically been the medium for recording and displaying motion pictures. Many other terms exist for an individual motion-picture, including picture, picture show, moving picture, photoplay, and fick. Te most common term in the United States is movie, while in Europe flm is preferred. Common terms for the feld in general include the big screen, the silver screen, the movies, and cinema; the last of these is commonly used, as an overarching term, in scholarly texts and critical essays. In early years, the word sheet was sometimes used instead of screen.

337 Te use of sequences of photographs in such devices was initially limited to a few experiments with subjects photographed in a series of poses because the available emulsions were not sensitive enough to allow the short exposures needed to photograph subjects that were actually moving. Te sensitivity was gradually improved and in the late 1870s, Eadweard Muybridge created the frst animated image sequences photographed in real-time. A row of cameras was used, each, in turn, capturing one image on a photographic glass plate, so the total number of images in each sequence was limited by the number of cameras, about two dozen at most. Muybridge used his system to analyze the movements of a wide variety of animal and human subjects. Hand-painted images based on the photographs were projected as moving images by means of his zoopraxiscope.[3]

Georges Méliès Le Voyage dans la Lune, showing a projectile in the man in the moon's eye from 1902 A famous shot from Georges Méliès Le Voyage dans la Lune (A Trip to the Moon) (1902), an early narrative flm and also an early science fction flm.

First motion pictures - by the end of the 1880s, the introduction of lengths of celluloid photographic flm and the invention of motion picture cameras, which could photograph an indefnitely long rapid sequence of images using only one lens, allowed several minutes of action to be captured and stored on a single compact reel of flm. Some early flms were made to be viewed by one person at a time through a "peep show" device such as the Kinetoscope and the mutoscope. Others were intended for a projector, mechanically similar to the camera and sometimes actually the same machine, which was used to shine an intense light through the processed and printed flm and into a projection lens so that these "moving pictures" could be shown tremendously enlarged on a screen for viewing by an entire audience. Te frst kinetoscope flm shown in public exhibition was Blacksmith Scene, produced by Edison Manufacturing Company in 1893. Te following year the company would begin Edison Studios, which became an early leader in the flm industry with notable early shorts including Te Kiss, and would go on to produce close to 1,200 flms.

Te frst public screenings of flms at which admission was charged were made in 1895 by the American Woodville Latham and his sons, using flms produced by their Eidoloscope company,[4] and by the – arguably better known – French brothers Auguste and Louis Lumière with ten of their own productions.[citation needed] Private screenings had preceded these by several months, with Latham's slightly predating the Lumière brothers'.[citation needed] Another opinion is that the frst public exhibition of projected motion pictures in America was at Brooklyn Institute in New York City 9 May 1893.

In the 1920s, the development of electronic sound recording technologies made it practical to incorporate a soundtrack of speech, music and sound eﬀects synchronized with the action on the screen.[citation needed] Te resulting sound flms were initially distinguished from the usual silent "moving pictures" or "movies" by calling them "talking pictures" or "talkies."[citation needed] Te revolution they wrought was swift. By 1930, silent flm was practically extinct in the US and already being referred to as "the old medium."[citation needed]

Another major technological development was the introduction of "natural color," which meant color that was photographically recorded from nature rather than added to black-and-white prints by hand-coloring, stencil-coloring or other arbitrary procedures, although the earliest processes typically yielded colors which were far from "natural" in appearance.[citation needed] While the advent of sound flms quickly made silent flms and theater musicians obsolete, color replaced black-and-white much more gradually.[citation needed] Te pivotal innovation was the introduction of the three- strip version of the Technicolor process, frst used for animated cartoons in 1932, then also for live-action short flms and isolated sequences in a few feature flms, then for an entire feature flm, Becky Sharp, in 1935. Te expense of the process

338 was daunting, but favorable public response in the form of increased box oﬃce receipts usually justifed the added cost. Te number of flms made in color slowly increased year after year.

In the early 1950s, the proliferation of black-and-white television started seriously depressing North American theater attendance.[citation needed] In an attempt to lure audiences back into theaters, bigger screens were installed, widescreen processes, polarized 3D projection, and stereophonic sound were introduced, and more flms were made in color, which soon became the rule rather than the exception. Some important mainstream Hollywood flms were still being made in black-and- white as late as the mid-1960s, but they marked the end of an era. Color television receivers had been available in the US since the mid-1950s, but at frst, they were very expensive and few broadcasts were in color. During the 1960s, prices gradually came down, color broadcasts became common, and sales boomed. Te overwhelming public verdict in favor of color was clear. After the fnal furry of black-and-white flms had been released in mid-decade, all Hollywood studio productions were flmed in color, with the usual exceptions made only at the insistence of "star" flmmakers such as Peter Bogdanovich and Martin Scorsese.[citation needed]

"Film theory" seeks to develop concise and systematic concepts that apply to the study of flm as art. Te concept of flm as an art-form began in 1911 with Ricciotto Canudo's Te Birth of the Sixth Art. Formalist flm theory, led by Rudolf Arnheim, Béla Balázs, and Siegfried Kracauer, emphasized how flm diﬀered from reality and thus could be considered a valid fne art. André Bazin reacted against this theory by arguing that flm's artistic essence lay in its ability to mechanically reproduce reality, not in its diﬀerences from reality, and this gave rise to realist theory. More recent analysis spurred by Jacques Lacan's psychoanalysis and Ferdinand de Saussure's semiotics among other things has given rise to psychoanalytic flm theory, structuralist flm theory, feminist flm theory, and others. On the other hand, critics from the analytical philosophy tradition, infuenced by Wittgenstein, try to clarify misconceptions used in theoretical studies and produce analysis of a flm's vocabulary and its link to a form of life.

Montage is the technique by which separate pieces of flm are selected, edited, and then pieced together to make a new section of flm. A scene could show a man going into battle, with fashbacks to his youth and to his home-life and with added special effects, placed into the flm after flming is complete. As these were all flmed separately, and perhaps with different actors, the fnal version is called a montage. Directors developed a theory of montage, beginning with Eisenstein and the complex juxtaposition of images in his flm Battleship Potemkin.[5] Incorporation of musical and visual counterpoint, and scene development through mise en scene, editing, and effects has led to more complex techniques comparable to those used in opera and ballet.

339 important. Poor reviews from leading critics at major papers and magazines will often reduce audience interest and attendance.

Te impact of a reviewer on a given flm's box office performance is a matter of debate. Some observers claim that movie marketing in the 2000s is so intense, well-coordinated and well fnanced that reviewers cannot prevent a poorly written or flmed blockbuster from attaining market success. However, the cataclysmic failure of some heavily promoted flms which were harshly reviewed, as well as the unexpected success of critically praised independent flms indicates that extreme critical reactions can have considerable infuence. Other observers note that positive flm reviews have been shown to spark interest in little-known flms. Conversely, there have been several flms in which flm companies have so little confdence that they refuse to give reviewers an advanced viewing to avoid widespread panning of the flm. However, this usually backfres, as reviewers are wise to the tactic and warn the public that the flm may not be worth seeing and the flms often do poorly as a result. Journalist flm critics are sometimes called flm reviewers. Critics who take a more academic approach to flms, through publishing in flm journals and writing books about flms using flm theory or flm studies approaches, study how flm and flming techniques work, and what effect they have on people. Rather than having their reviews published in newspapers or appearing on television, their articles are published in scholarly journals or up-market magazines. Tey also tend to be affiliated with colleges or universities as professors or instructors.

Babelsberg Studio near Berlin gate with pedestrian island Founded in 1912, the Babelsberg Studio near Berlin was the frst large-scale flm studio in the world, and the forerunner to Hollywood. It still produces global blockbusters every year. Te making and showing of motion pictures became a source of proft almost as soon as the process was invented. Upon seeing how successful their new invention, and its product, was in their native France, the Lumières quickly set about touring the Continent to exhibit the frst flms privately to royalty and publicly to the masses. In each country, they would normally add new, local scenes to their catalogue and, quickly enough, found local entrepreneurs in the various countries of Europe to buy their equipment and photograph, export, import, and screen additional product commercially. Te Oberammergau Passion Play of 1898[citation needed] was the frst commercial motion picture ever produced. Other pictures soon followed, and motion pictures became a separate industry that overshadowed the vaudeville world. Dedicated theaters and companies formed specifcally to produce and distribute flms, while motion picture actors became major celebrities and commanded huge fees for their performances. By 1917 Charlie Chaplin had a contract that called for an annual salary of one million dollars. From 1931 to 1956, flm was also the only image storage and playback system for television programming until the introduction of videotape recorders.

In the United States, much of the flm industry is centered around Hollywood, California. Other regional centers exist in many parts of the world, such as Mumbai-centered Bollywood, the Indian flm industry's Hindi cinema which produces the largest number of flms in the world.[6] Tough the expense involved in making flms has led cinema production to concentrate under the auspices of movie studios, recent advances in aﬀordable flm making equipment have allowed independent flm productions to fourish.

340 "flm" and "movie" are sometimes used interchangeably, "flm" is more often used when considering artistic, theoretical, or technical aspects. Te term "movies" more often refers to entertainment or commercial aspects, as where to go for fun evening on a date. For example, a book titled "How to Understand a Film" would probably be about the aesthetics or theory of flm, while a book entitled "Let's Go to the Movies" would probably be about the history of entertaining movies and blockbusters.

Further terminology is used to distinguish various forms and media used in the flm industry. "Motion pictures" and "moving pictures" are frequently used terms for flm and movie productions specifcally intended for theatrical exhibition, such as, for instance, Batman. "DVD" and "videotape" are video formats that can reproduce a photochemical flm. A reproduction based on such is called a "transfer." After the advent of theatrical flm as an industry, the television industry began using videotape as a recording medium. For many decades, tape was solely an analog medium onto which moving images could be either recorded or transferred. "Film" and "flming" refer to the photochemical medium that chemically records a visual image and the act of recording respectively. However, the act of shooting images with other visual media, such as with a digital camera, is still called "flming" and the resulting works often called "flms" as interchangeable to "movies," despite not being shot on flm. "Silent flms" need not be utterly silent, but are flms and movies without an audible dialogue, including those that have a musical accompaniment. Te word, "Talkies," refers to the earliest sound flms created to have audible dialogue recorded for playback along with the flm, regardless of a musical accompaniment. "Cinema" either broadly encompasses both flms and movies, or it is roughly synonymous with flm and theatrical exhibition, and both are capitalized when referring to a category of art. Te "silver screen" refers to the projection screen used to exhibit flms and, by extension, is also used as a metonym for the entire flm industry.

"Widescreen" refers to a larger width to height in the frame, compared to earlier historic aspect ratios.[10] A "feature-length flm", or "feature flm", is of a conventional full length, usually 60 minutes or more, and can commercially stand by itself without other flms in a ticketed screening.[11] A "short" is a flm that is not as long as a feature-length flm, often screened with other shorts, or preceding a feature-length flm. An "independent" is a flm made outside the conventional flm industry.

In US usage, one talks of a "screening" or "projection" of a movie or video on a screen at a public or private "theater." In British English, a "flm showing" happens at a cinema (never a "theatre", which is a different medium and place altogether). [9] A cinema usually refers to an arena designed specifcally to exhibit flms, where the screen is affixed to a wall, while a theater usually refers to a place where live, non-recorded action or combination thereof occurs from a podium or other type of stage, including the amphitheater. Teaters can still screen movies in them, though the theater would be retroftted to do so. One might propose "going to the cinema" when referring to the activity, or sometimes "to the pictures" in British English, whereas the US expression is usually "going to the movies." A cinema usually shows a mass-marketed movie using a front-projection screen process with either a flm projector or, more recently, with a digital projector. But, cinemas may also show theatrical movies from their home video transfers that include Blu-ray Disc, DVD, and videocassette when they possess sufficient projection quality or based upon need, such as movies that exist only in their transferred state, which may be due to the loss or deterioration of the flm master and prints from which the movie originally existed. Due to the advent of digital flm production and distribution, physical flm might be absent entirely. A "double feature" is a screening of two independently marketed, stand-alone feature flms. A "viewing" is a watching of a flm. "Sales" and "at the box office" refer to tickets sold at a theater, or more currently, rights sold for individual showings. A "release" is the distribution and often simultaneous screening of a flm. A "preview" is a screening in advance of the main release.

Te "credits," or "end credits," is a list that gives credit to the people involved in the production of a flm. Films from before the 1970s usually start a flm with credits, often ending with only a title card, saying "Te End" or some equivalent, often an equivalent that depends on the language of the production[citation needed]. From then onward, a flm's credits usually appear at the end of most flms. However, flms with credits that end a flm often repeat some credits at or near the start of a flm and therefore appear twice, such as that flm's acting leads, while less frequently some appearing near or at the beginning only appear there, not at the end, which often happens to the director's credit. Te credits appearing at or near the beginning of a flm are usually called "titles" or "beginning titles." A post-credits scene is a scene shown after the end of the credits. Ferris Bueller's Day Oﬀ has a post-credit scene in which Ferris tells the audience that the flm is over and they should go home.

341 A flm's "cast" refers to a collection of the actors and actresses who appear, or "star," in a flm. A star is an actor or actress, often a popular one, and in many cases, a celebrity who plays a central character in a flm. Occasionally the word can also be used to refer to the fame of other members of the crew, such as a director or other personality, such as Martin Scorsese. A "crew" is usually interpreted as the people involved in a flm's physical construction outside cast participation, and it could include directors, flm editors, photographers, grips, gaﬀers, set decorators, prop masters, and costume designers. A person can both be part of a flm's cast and crew, such as Woody Allen, who directed and starred in Take the Money and Run.

A preview performance refers to a showing of a flm to a select audience, usually for the purposes of corporate promotions, before the public flm premiere itself. Previews are sometimes used to judge audience reaction, which if unexpectedly negative, may result in recutting or even reflming certain sections based on the audience response. One example of a flm that was changed after a negative response from the test screening is 1982's First Blood. After the test audience responded very negatively to the death of protagonist John Rambo, a Vietnam veteran, at the end of the flm, the company wrote and re-shot a new ending in which the character survives.[12]

Trailers or previews are advertisements for flms that will be shown in 1 to 3 months at a cinema. Back in the early days of cinema, with theaters that had only one or two screens, only certain trailers were shown for the flms that were going to be shown there. Later, when theaters added more screens or new theaters were built with a lot of screens, all diﬀerent trailers were shown even if they weren't going to play that flm in that theater. Film studios realized that the more trailers that were shown (even if it wasn't going to be shown in that particular theater) the more patrons would go to a diﬀerent theater to see the flm when it came out. Te term "trailer" comes from their having originally been shown at the end of a flm program. Tat practice did not last long because patrons tended to leave the theater after the flms ended, but the name has stuck. Trailers are now shown before the flm (or the "A flm" in a double feature program) begins. Film trailers are also common on DVDs and Blu-ray Discs, as well as on the Internet and mobile devices. Trailers are created to be engaging and interesting for viewers. As a result, in the Internet era, viewers often seek out trailers to watch them. Of the ten billion videos watched online annually in 2008, flm trailers ranked third, after news and user-created videos.[13] Teasers are a much shorter preview or advertisement that lasts only 10 to 30 seconds. Teasers are used to get patrons excited about a flm coming out in the next six to twelve months. Teasers may be produced even before the flm production is completed.

Production

342 A flm crew is a group of people hired by a flm company, employed during the "production" or "photography" phase, for the purpose of producing a flm or motion picture. Crew is distinguished from cast, who are the actors who appear in front of the camera or provide voices for characters in the flm. Te crew interacts with but is also distinct from the production staff, consisting of producers, managers, company representatives, their assistants, and those whose primary responsibility falls in pre-production or post-production phases, such as screenwriters and flm editors. Communication between production and crew generally passes through the director and his/her staff of assistants. Medium-to-large crews are generally divided into departments with well-defned hierarchies and standards for interaction and cooperation between the departments. Other than acting, the crew handles everything in the photography phase: props and costumes, shooting, sound, electrics (i.e., lights), sets, and production special effects. Caterers (known in the flm industry as "craft services") are usually not considered part of the crew.

Film stock consists of transparent celluloid, acetate, or polyester base coated with an emulsion containing light-sensitive chemicals. Cellulose nitrate was the frst type of flm base used to record motion pictures, but due to its fammability was eventually replaced by safer materials. Stock widths and the flm format for images on the reel have had a rich history, though most large commercial flms are still shot on (and distributed to theaters) as 35 mm prints. Originally moving picture flm was shot and projected at various speeds using hand-cranked cameras and projectors; though 1000 frames per minute (16 frame/s) is generally cited as a standard silent speed, research indicates most flms were shot between 16 frame/s and 23 frame/s and projected from 18 frame/s on up (often reels included instructions on how fast each scene should be shown).[14] When sound flm was introduced in the late 1920s, a constant speed was required for the sound head. 24 frames per second were chosen because it was the slowest (and thus cheapest) speed which allowed for suﬃcient sound quality.[citation needed] Improvements since the late 19th century include the mechanization of cameras – allowing them to record at a consistent speed, quiet camera design – allowing sound recorded on-set to be usable without requiring large "blimps" to encase the camera, the invention of more sophisticated flmstocks and lenses, allowing directors to flm in increasingly dim conditions, and the development of synchronized sound, allowing sound to be recorded at exactly the same speed as its corresponding action. Te soundtrack can be recorded separately from shooting the flm, but for live-action pictures, many parts of the soundtrack are usually recorded simultaneously.

Independent

Independent flmmaking often takes place outside Hollywood, or other major studio systems. An independent flm (or indie flm) is a flm initially produced without fnancing or distribution from a major flm studio. Creative, business and technological reasons have all contributed to the growth of the indie flm scene in the late 20th and early 21st century. On the business side, the costs of big-budget studio flms also lead to conservative choices in cast and crew. Tere is a trend in Hollywood towards co-fnancing (over two-thirds of the flms put out by Warner Bros. in 2000 were joint ventures, up from 10% in 1987).[15] A hopeful director is almost never given the opportunity to get a job on a big-budget studio flm unless he or she has signifcant industry experience in flm or television. Also, the studios rarely produce flms with unknown actors, particularly in lead roles.

343 signifcantly. Both production and post-production costs have been signifcantly lowered; in the 2000s, the hardware and software for post-production can be installed in a commodity-based personal computer. Technologies such as DVDs, FireWire connections and a wide variety of professional and consumer-grade video editing software make flm-making relatively aﬀordable.

Distribution

Animation

Limited animation is a way of increasing production and decreasing costs of animation by using "short cuts" in the animation process. Tis method was pioneered by UPA and popularized by Hanna-Barbera in the United States, and by Osamu Tezuka in Japan, and adapted by other studios as cartoons moved from movie theaters to television.[16] Although most animation studios are now using digital technologies in their productions, there is a specifc style of animation that depends on flm. Camera-less animation, made famous by flm-makers like Norman McLaren, Len Lye, and Stan Brakhage, is painted and drawn directly onto pieces of flm, and then run through a projector.

Comedy

344 Other forms of comedy include screwball comedy, which derives its humour largely from bizarre, surprising (and improbable) situations or characters, and black comedy, which is characterized by a form of humor that includes darker aspects of human behavior or human nature. Similarly scatological humour, sexual humour, and race humour create comedy by violating social conventions or taboos in comic ways. A comedy of manners typically takes as its subject a particular part of society (usually upper class society) and uses humor to parody or satirize the behaviour and mannerisms of its members. Romantic comedy is a popular genre that depicts burgeoning romance in humorous terms and focuses on the foibles of those who are falling in love.

Te word "comedy" is derived from the Classical Greek κωμῳδία kōmōidía, which is a compound either of κῶμος kômos (revel) or κώμη kṓmē (village) and ᾠδή ōidḗ (singing); it is possible that κῶμος itself is derived from κώμη, and originally meant a village revel. Te adjective "comic" (Greek κωμικός kōmikós), which strictly means that which relates to comedy is, in modern usage, generally confned to the sense of "laughter-provoking". Of this, the word came into modern usage through the Latin comoedia and Italian commedia and has, over time, passed through various shades of meaning.

Te Greeks and Romans confned their use of the word "comedy" to descriptions of stage-plays with happy endings. Aristotle defned comedy as an imitation of men worse than the average (where tragedy was an imitation of men better than the average). However, the characters portrayed in comedies were not worse than average in every way, only insofar as they are Ridiculous, which is a species of the Ugly. Te Ridiculous may be defned as a mistake or deformity not productive of pain or harm to others; the mask, for instance, that excites laughter, is something ugly and distorted without causing pain. In the Middle Ages, the term expanded to include narrative poems with happy endings. It is in this sense that Dante used the term in the title of his poem, La Commedia.

As time progressed, the word came more and more to be associated with any sort of performance intended to cause laughter. During the Middle Ages, the term "comedy" became synonymous with satire, and later with humour in general.

Aristotle's Poetics was translated into Arabic in the medieval Islamic world, where it was elaborated upon by Arabic writers and Islamic philosophers, such as Abu Bischr, and his pupils Al-Farabi, Avicenna, and Averroes. Tey disassociated comedy from Greek dramatic representation and instead identifed it with Arabic poetic themes and forms, such as hija (satirical poetry). Tey viewed comedy as simply the "art of reprehension", and made no reference to light and cheerful events, or to the troubling beginnings and happy endings associated with classical Greek comedy.

After the Latin translations of the 12th century, the term "comedy" gained a more general meaning in medieval literature.

In the late 20th century, many scholars preferred to use the term laughter to refer to the whole gamut of the comic, in order to avoid the use of ambiguous and problematically defned genres such as the grotesque, irony, and satire.

Roman-era mosaic depicting a scene from Menander's comedy Samia ("Te Woman from Samos”) Starting from 425 BCE, Aristophanes, a comic playwright and satirical author of the Ancient Greek Teater wrote 40 comedies, 11 of which survive. Aristophanes developed his type of comedy from the earlier satyr plays, which were often highly obscene. Of the satyr plays the only surviving examples are by Euripides which are much later examples and not representative of the genre. In ancient Greece, comedy originated in bawdy and ribald songs or recitations apropos of phallic processions and fertility festivals or gatherings.

Around 335 BCE, Aristotle, in his work Poetics, stated that comedy originated in Phallic processions and the light treatment of the otherwise base and ugly. He also adds that the origins of comedy are obscure because it was not treated seriously from its inception. However, comedy had its own Muse: Talia.

Aristotle taught that comedy was generally a positive for society, since it brings forth happiness, which for Aristotle was the ideal state, the fnal goal in any activity. For Aristotle, a comedy did not need to involve sexual humor. A comedy is about the fortunate arise of a sympathetic character. Aristotle divides comedy into three categories or subgenres: farce, romantic comedy, and satire. On the contrary, Plato taught that comedy is a destruction to the self. He believed that it produces an emotion that overrides rational self-control and learning. In Te Republic, he says that the Guardians of the state should avoid laughter, " 'for ordinarily when one abandons himself to violent laughter, his condition provokes a violent reaction.' " Plato says comedy should be tightly controlled if one wants to achieve the ideal state.

Also in Poetics, Aristotle defned Comedy as one of the original four genres of literature. Te other three genres are tragedy, epic poetry, and lyric poetry. Literature in general is defned by Aristotle as a mimesis, or imitation of life. Comedy is the third form of literature, being the most divorced from a true mimesis. Tragedy is the truest mimesis, followed by epic poetry, comedy and lyric poetry. Te genre of comedy is defned by a certain pattern according to Aristotle's defnition. Comedies 345 begin with low or base characters seeking insignifcant aims, and end with some accomplishment of the aims which either lightens the initial baseness or reveals the insignifcance of the aims.

By 200 BCE, in ancient Sanskrit drama, Bharata Muni's Natya Shastra defned humour (hāsyam) as one of the nine nava rasas, or principle rasas (emotional responses), which can be inspired in the audience by bhavas, the imitations of emotions that the actors perform. Each rasa was associated with a specifc bhavas portrayed on stage. In the case of humour, it was associated with mirth (hasya).

Title page of the frst quarto of Shakespeare's Midsummer Night's Dream (1600) "Comedy", in its Elizabethan usage, had a very diﬀerent meaning from modern comedy. A Shakespearean comedy is one that has a happy ending, usually involving marriages between the unmarried characters, and a tone and style that is more light-hearted than Shakespeare's other plays.

Te Punch and Judy show has roots in the 16th-century Italian commedia dell'arte. Te fgure of Punch derives from the Neapolitan stock character of Pulcinella. Te fgure who later became Mr. Punch made his frst recorded appearance in England in 1662. Punch and Judy are performed in the spirit of outrageous comedy — often provoking shocked laughter — and are dominated by the anarchic clowning of Mr. Punch. Appearing at a signifcant period in British history, professor Glyn Edwards states: "[Pulcinella] went down particularly well with Restoration British audiences, fun-starved after years of Puritanism. We soon changed Punch's name, transformed him from a marionette to a hand puppet, and he became, really, a spirit of Britain - a subversive maverick who defes authority, a kind of puppet equivalent to our political cartoons."

In early 19th century England, pantomime acquired its present form which includes slapstick comedy and featured the frst mainstream clown Joseph Grimaldi, while comedy routines also featured heavily in British music hall theatre which became popular in the 1850s. British comedians who honed their skills in music hall sketches include Charlie Chaplin, Stan Laurel and Dan Leno. English music hall comedian and theatre impresario Fred Karno developed a form of sketch comedy without dialogue in the 1890s, and Chaplin and Laurel were among the comedians who worked for his company. Karno was a pioneer of slapstick, and in his biography Laurel stated, "Fred Karno didn't teach Charlie [Chaplin] and me all we know about comedy. He just taught us most of it". Film producer Hal Roach stated: "Fred Karno is not only a genius, he is the man who originated slapstick comedy. We in Hollywood owe much to him." American vaudeville emerged in the 1880s and remained popular until the 1930s, and featured comedians such as W. C. Fields, Buster Keaton and the Marx Brothers.

Te phenomena connected with laughter and that which provokes it have been carefully investigated by psychologists. Tey agree the predominant characteristics are incongruity or contrast in the object and shock or emotional seizure on the part of the subject. It has also been held that the feeling of superiority is an essential factor: thus Tomas Hobbes speaks of laughter as a "sudden glory". Modern investigators have paid much attention to the origin both of laughter and of smiling, as well as the development of the "play instinct" and its emotional expression.

George Meredith said that "One excellent test of the civilization of a country ... I take to be the fourishing of the Comic idea and Comedy; and the test of true Comedy is that it shall awaken thoughtful laughter." Laughter is said to be the cure to being sick. Studies show that people who laugh more often get sick less.

American literary theorist Kenneth Burke writes that the "comic frame" in rhetoric is "neither wholly euphemistic, nor wholly debunking—hence it provides the charitable attitude towards people that is required for purposes of persuasion and co-operation, but at the same time maintains our shrewdness concerning the simplicities of ‘cashing in.’" Te purpose of the comic frame is to satirize a given circumstance and promote change by doing so. Te comic frame makes fun of situations and people, while simultaneously provoking thought. Te comic frame does not aim to vilify in its analysis, but rather, rebuke the stupidity and foolery of those involved in the circumstances. For example, on Te Daily Show, Jon Stewart uses the "comic frame" to intervene in political arguments, one such way is his sudden contrast of serious news with crude humor. In a segment on President Obama's trip to China Stewart remarks on America's debt to the Chinese government while also having a weak relationship with the country. After depicting this dismal situation, Stewart shifts to speak directly to President Obama, calling upon him to "shine that turd up." For Stewart and his audience, introducing coarse language into what is otherwise a serious commentary on the state of foreign relations serves to frame the segment comically, creating a serious tone underlying the comedic agenda presented by Stewart.

Comedy may be divided into multiple genres based on the source of humor, the method of delivery, and the context in which it is delivered. Te diﬀerent forms of comedy often overlap, and most comedy can ft into multiple genres. Some of the subgenres of comedy are farce, comedy of manners, burlesque, and satire.

Some comedy apes certain cultural forms: for instance, parody and satire often imitate the conventions of the genre they are parodying or satirizing. For example, in the United States, parodies of newspapers and television news include Te Onion,

346 and Te Colbert Report; in Australia, shows such as Kath & Kim, Utopia, and Shaun Micallef's Mad As Hell perform the same role.

Self-deprecation is a technique of comedy used by many comedians who focus on their misfortunes and foibles in order to entertain.

Media

Te media is a diversifed collection of media technologies that reach a large audience via mass communication. Te technologies through which this communication takes place include a variety of outlets.

Broadcast media transmit information electronically via media such as flms, radio, recorded music, or television. Digital media comprises both Internet and mobile mass communication. Internet media comprise such services as email, social media sites, websites, and Internet-based radio and television. Many other mass media outlets have an additional presence on the web, by such means as linking to or running TV ads online, or distributing QR Codes in outdoor or print media to direct mobile users to a website. In this way, they can utilise the easy accessibility and outreach capabilities the Internet affords, as thereby easily broadcast information throughout many different regions of the world simultaneously and cost- efficiently. Outdoor media transmit information via such media as AR advertising; billboards; blimps; fying billboards (signs in tow of airplanes); placards or kiosks placed inside and outside buses, commercial buildings, shops, sports stadiums, subway cars, or trains; signs; or skywriting.[1] Print media transmit information via physical objects, such as books, comics, magazines, newspapers, or pamphlets.[2] Event organizing and public speaking can also be considered forms of mass media. [3] In the late 20th century, mass media could be classifed into eight mass media industries: books, the Internet, magazines, movies, newspapers, radio, recordings, and television. Te explosion of digital communication technology in the late 20th and early 21st centuries made prominent the question: what forms of media should be classifed as "mass media"? For example, it is controversial whether to include cell phones, computer games (such as MMORPGs), and video games in the defnition. In the 2000s, a classifcation called the "seven mass media" became popular.[citation needed] In order of introduction, they are:

While a telephone is a two-way communication device, mass media communicates to a large group. In addition, the telephone has transformed into a cell phone which is equipped with Internet access. A question arises whether this makes cell phones a mass medium or simply a device used to access a mass medium (the Internet). Tere is currently a system by which marketers and advertisers are able to tap into satellites, and broadcast commercials and advertisements directly to cell phones, unsolicited by the phone's user.[citation needed] Tis transmission of mass advertising to millions of people is another form of mass communication.

Video games may also be evolving into a mass medium. Video games (for example massively multiplayer online role-playing games (MMORPGs), such as RuneScape) provide a common gaming experience to millions of users across the globe and convey the same messages and ideologies to all their users. Users sometimes share the experience with one another by playing online. Excluding the Internet however, it is questionable whether players of video games are sharing a common experience when they play the game individually. It is possible to discuss in great detail the events of a video game with a friend one has never played with, because the experience is identical to each. Te question, then, is whether this is a form of mass communication.

In common usage, the term "mass" denotes not that a given number of individuals receives the products, but rather that the products are available in principle to a plurality of recipients.[7]

Forms of mass media Broadcast

A family listening to a crystal radio in the 1920s. Main articles: Radio broadcasting and Television Te sequencing of content in a broadcast is called a schedule. With all technological endeavours a number of technical terms and slang have developed. Please see the list of broadcasting terms for a glossary of terms used.

347 Radio and television programs are distributed over frequency bands which are highly regulated in the United States. Such regulation includes determination of the width of the bands, range, licensing, types of receivers and transmitters used, and acceptable content.

Cable television programs are often broadcast simultaneously with radio and television programs, but have a more limited audience. By coding signals and requiring a cable converter box at individual recipients' locations, cable also enables subscription-based channels and pay-per-view services.

A broadcasting organisation may broadcast several programs simultaneously, through several channels (frequencies), for example BBC One and Two. On the other hand, two or more organisations may share a channel and each use it during a fxed part of the day, such as the Cartoon Network/Adult Swim. Digital radio and digital television may also transmit multiplexed programming, with several channels compressed into one ensemble.

When broadcasting is done via the Internet the term webcasting is often used. In 2004, a new phenomenon occurred when a number of technologies combined to produce podcasting. Podcasting is an asynchronous broadcast/narrowcast medium. Adam Curry and his associates, the Podshow, are principal proponents of podcasting.

Te term 'flm' encompasses motion pictures as individual projects, as well as the feld in general. Te name comes from the photographic flm (also called flmstock), historically the primary medium for recording and displaying motion pictures. Many other terms for flm exist, such as motion pictures (or just pictures and "picture"), the silver screen, photoplays, the cinema, picture shows, ficks, and most common, movies.

Films are produced by recording people and objects with cameras, or by creating them using animation techniques or special effects. Films comprise a series of individual frames, but when these images are shown in rapid succession, an illusion of motion is created. Flickering between frames is not seen because of an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after the source has been removed. Also of relevance is what causes the perception of motion: a psychological effect identifed as beta movement.

Film is considered by many[who?] to be an important art form; flms entertain, educate, enlighten, and inspire audiences. Any flm can become a worldwide attraction, especially with the addition of dubbing or subtitles that translate the flm message. Films are also artifacts created by specifc cultures, which refect those cultures, and, in turn, aﬀect them.

A video game is a computer-controlled game in which a video display, such as a monitor or television, is the primary feedback device. Te term "computer game" also includes games which display only text (and which can, therefore, theoretically be played on a teletypewriter) or which use other methods, such as sound or vibration, as their primary feedback device, but there are very few new games in these categories.[who?] Tere always must also be some sort of input device, usually in the form of button/joystick combinations (on arcade games), a keyboard and mouse/trackball combination (computer games), a controller (console games), or a combination of any of the above. Also, more esoteric devices have been used for input, e.g., the player's motion. Usually there are rules and goals, but in more open-ended games the player may be free to do whatever they like within the confnes of the virtual universe.

In common usage, an "arcade game" refers to a game designed to be played in an establishment in which patrons pay to play on a per-use basis. A "computer game" or "PC game" refers to a game that is played on a personal computer. A "Console game" refers to one that is played on a device specifcally designed for the use of such, while interfacing with a standard television set. A "video game" (or "videogame") has evolved into a catchall phrase that encompasses the aforementioned along with any game made for any other device, including, but not limited to, advanced calculators, mobile phones, PDAs, etc.

Sound recording and reproduction is the electrical or mechanical re-creation or amplifcation of sound, often as music. Tis involves the use of audio equipment such as microphones, recording devices, and loudspeakers. From early beginnings with the invention of the phonograph using purely mechanical techniques, the feld has advanced with the invention of electrical recording, the mass production of the 78 record, the magnetic wire recorder followed by the tape recorder, the vinyl LP record. Te invention of the compact cassette in the 1960s, followed by Sony's Walkman, gave a major boost to the mass distribution of music recordings, and the invention of digital recording and the compact disc in 1983 brought massive improvements in ruggedness and quality. Te most recent developments have been in digital audio players.

An album is a collection of related audio recordings, released together to the public, usually commercially.

348 Te term record album originated from the fact that 78 RPM Phonograph disc records were kept together in a book resembling a photo album. Te frst collection of records to be called an "album" was Tchaikovsky's Nutcracker Suite, release in April 1909 as a four-disc set by Odeon records.[8][9] It retailed for 16 shillings – about £15 in modern currency.

A music video (also promo) is a short flm or video that accompanies a complete piece of music, most commonly a song. Modern music videos were primarily made and used as a marketing device intended to promote the sale of music recordings. Although the origins of music videos go back much further, they came into their own in the 1980s, when Music Television's format was based on them. In the 1980s, the term "rock video" was often used to describe this form of entertainment, although the term has fallen into disuse.

Music videos can accommodate all styles of flmmaking, including animation, live action flms, documentaries, and non- narrative, abstract flm.

Te Internet (also known simply as "the Net" or less precisely as "the Web") is a more interactive medium of mass media, and can be briefy described as "a network of networks". Specifcally, it is the worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It consists of millions of smaller domestic, academic, business, and governmental networks, which together carry various information and services, such as email, online chat, fle transfer, and the interlinked web pages and other documents of the World Wide Web.

Contrary to some common usage, the Internet and the World Wide Web are not synonymous: the Internet is the system of interconnected computer networks, linked by copper wires, fber-optic cables, wireless connections etc.; the Web is the contents, or the interconnected documents, linked by hyperlinks and URLs. Te World Wide Web is accessible through the Internet, along with many other services including e-mail, fle sharing and others described below.

Toward the end of the 20th century, the advent of the World Wide Web marked the frst era in which most individuals could have a means of exposure on a scale comparable to that of mass media. Anyone with a web site has the potential to address a global audience, although serving to high levels of web traﬃc is still relatively expensive. It is possible that the rise of peer-to-peer technologies may have begun the process of making the cost of bandwidth manageable. Although a vast amount of information, imagery, and commentary (i.e. "content") has been made available, it is often diﬃcult to determine the authenticity and reliability of information contained in web pages (in many cases, self-published). Te invention of the Internet has also allowed breaking news stories to reach around the globe within minutes. Tis rapid growth of instantaneous, decentralized communication is often deemed likely to change mass media and its relationship to society.

"Cross-media" means the idea of distributing the same message through different media channels. A similar idea is expressed in the news industry as "convergence". Many authors understand cross-media publishing to be the ability to publish in both print and on the web without manual conversion effort. An increasing number of wireless devices with mutually incompatible data and screen formats make it even more difficult to achieve the objective "create once, publish many".

Te Internet is quickly becoming the center of mass media. Everything is becoming accessible via the internet. Rather than picking up a newspaper, or watching the 10 o'clock news, people can log onto the internet to get the news they want, when they want it. For example, many workers listen to the radio through the Internet while sitting at their desk.

Even the education system relies on the Internet. Teachers can contact the entire class by sending one e-mail. Tey may have web pages on which students can get another copy of the class outline or assignments. Some classes have class blogs in which students are required to post weekly, with students graded on their contributions.

Blogging, too, has become a pervasive form of media. A blog is a website, usually maintained by an individual, with regular entries of commentary, descriptions of events, or interactive media such as images or video. Entries are commonly displayed in reverse chronological order, with most recent posts shown on top. Many blogs provide commentary or news on a particular subject; others function as more personal online diaries. A typical blog combines text, images and other graphics, and links to other blogs, web pages, and related media. Te ability for readers to leave comments in an interactive format is an important part of many blogs. Most blogs are primarily textual, although some focus on art (artlog), photographs (photoblog), sketchblog, videos (vlog), music (MP3 blog), audio (podcasting) are part of a wider network of social media. Microblogging is another type of blogging which consists of blogs with very short posts.

RSS is a format for syndicating news and the content of news-like sites, including major news sites like Wired, news-oriented community sites like Slashdot, and personal blogs. It is a family of Web feed formats used to publish frequently updated content such as blog entries, news headlines, and podcasts. An RSS document (which is called a "feed" or "web feed" or

349 "channel") contains either a summary of content from an associated web site or the full text. RSS makes it possible for people to keep up with web sites in an automated manner that can be piped into special programs or fltered displays.

A podcast is a series of digital-media fles which are distributed over the Internet using syndication feeds for playback on portable media players and computers. Te term podcast, like broadcast, can refer either to the series of content itself or to the method by which it is syndicated; the latter is also called podcasting. Te host or author of a podcast is often called a podcaster.

Mobile phones were introduced in Japan in 1979 but became a mass media only in 1998 when the frst downloadable ringing tones were introduced in Finland. Soon most forms of media content were introduced on mobile phones, tablets and other portable devices, and today the total value of media consumed on mobile vastly exceeds that of internet content, and was worth over 31 billion dollars in 2007 (source Informa). Te mobile media content includes over 8 billion dollars worth of mobile music (ringing tones, ringback tones, truetones, MP3 fles, karaoke, music videos, music streaming services etc.); over 5 billion dollars worth of mobile gaming; and various news, entertainment and advertising services. In Japan mobile phone books are so popular that fve of the ten best-selling printed books were originally released as mobile phone books.

Similar to the internet, mobile is also an interactive media, but has far wider reach, with 3.3 billion mobile phone users at the end of 2007 to 1.3 billion internet users (source ITU). Like email on the internet, the top application on mobile is also a personal messaging service, but SMS text messaging is used by over 2.4 billion people. Practically all internet services and applications exist or have similar cousins on mobile, from search to multiplayer games to virtual worlds to blogs. Mobile has several unique benefts which many mobile media pundits claim make mobile a more powerful media than either TV or the internet, starting with mobile being permanently carried and always connected. Mobile has the best audience accuracy and is the only mass media with a built-in payment channel available to every user without any credit cards or PayPal accounts or even an age limit. Mobile is often called the 7th Mass Medium and either the fourth screen (if counting cinema, TV and PC screens) or the third screen (counting only TV and PC).

Print Media

A magazine is a periodical publication containing a variety of articles, generally fnanced by advertising or purchase by readers.

Magazines are typically published weekly, biweekly, monthly, bimonthly or quarterly, with a date on the cover that is in advance of the date it is actually published. Tey are often printed in color on coated paper, and are bound with a soft cover.

Magazines fall into two broad categories: consumer magazines and business magazines. In practice, magazines are a subset of periodicals, distinct from those periodicals produced by scientifc, artistic, academic or special interest publishers which are subscription-only, more expensive, narrowly limited in circulation, and often have little or no advertising.

A newspaper is a publication containing news and information and advertising, usually printed on low-cost paper called newsprint. It may be general or special interest, most often published daily or weekly. Te most important function of newspapers is to inform the public of signifcant events.[10] Local newspapers inform local communities and include advertisements from local businesses and services, while national newspapers tend to focus on a theme, which can be exampled with "Te Wall Street Journal" as they oﬀer news on fnance and business related-topics.[10] Te frst printed newspaper was published in 1605, and the form has thrived even in the face of competition from technologies such as radio and television. Recent developments on the Internet are posing major threats to its business model, however. Paid circulation is declining in most countries, and advertising revenue, which makes up the bulk of a newspaper's income, is shifting from print to online; some commentators, nevertheless, point out that historically new media such as radio and television did not entirely supplant existing.

Te internet has challenged the press as an alternative source of information and opinion but has also provided a new platform for newspaper organizations to reach new audiences.[11] According to the World Trends Report, between 2012 and 2016, print newspaper circulation continued to fall in almost all regions, with the exception of Asia and the Pacifc, where the dramatic increase in sales in a few select countries has oﬀset falls in historically strong Asian markets such as Japan and the Republic of Korea. Most notably, between 2012 and 2016, India’s print circulation grew by 89 per cent.

Outdoor media is a form of mass media which comprises billboards, signs, placards placed inside and outside commercial buildings/objects like shops/buses, fying billboards (signs in tow of airplanes), blimps, skywriting, AR Advertising. Many commercial advertisers use this form of mass media when advertising in sports stadiums. Tobacco and alcohol manufacturers

350 used billboards and other outdoor media extensively. However, in 1998, the Master Settlement Agreement between the US and the tobacco industries prohibited the billboard advertising of cigarettes. In a 1994 Chicago-based study, Diana Hackbarth and her colleagues revealed how tobacco- and alcohol-based billboards were concentrated in poor neighbourhoods. In other urban centers, alcohol and tobacco billboards were much more concentrated in African-American neighborhoods than in white neighborhoods.[1]

Journalism is the discipline of collecting, analyzing, verifying and presenting information regarding current events, trends, issues and people. Tose who practice journalism are known as journalists.

News-oriented journalism is sometimes described as the "frst rough draft of history" (attributed to Phil Graham), because journalists often record important events, producing news articles on short deadlines. While under pressure to be frst with their stories, news media organizations usually edit and proofread their reports prior to publication, adhering to each organization's standards of accuracy, quality and style. Many news organizations claim proud traditions of holding government oﬃcials and institutions accountable to the public, while media critics have raised questions about holding the press itself accountable to the standards of professional journalism.

Public relations is the art and science of managing communication between an organization and its key publics to build, manage and sustain its positive image. Examples include:

Corporations use marketing public relations to convey information about the products they manufacture or services they provide to potential customers to support their direct sales efforts. Typically, they support sales in the short and long term, establishing and burnishing the corporation's branding for a strong, ongoing market. Corporations also use public relations as a vehicle to reach legislators and other politicians, seeking favorable tax, regulatory, and other treatment, and they may use public relations to portray themselves as enlightened employers, in support of human-resources recruiting programs. Nonproft organizations, including schools and universities, hospitals, and human and social service agencies, use public relations in support of awareness programs, fund-raising programs, staff recruiting, and to increase patronage of their services. Politicians use public relations to attract votes and raise money, and when successful at the ballot box, to promote and defend their service in office, with an eye to the next election or, at career's end, to their legacy. Publishing is the industry concerned with the production of literature or information – the activity of making information available for public view. In some cases, authors may be their own publishers.

Traditionally, the term refers to the distribution of printed works such as books and newspapers. With the advent of digital information systems and the Internet, the scope of publishing has expanded to include websites, blogs, and the like.

As a business, publishing includes the development, marketing, production, and distribution of newspapers, magazines, books, literary works, musical works, software, other works dealing with information.

Publication is also important as a legal concept; (1) as the process of giving formal notice to the world of a signifcant intention, for example, to marry or enter bankruptcy, and; (2) as the essential precondition of being able to claim defamation; that is, the alleged libel must have been published.

A software publisher is a publishing company in the software industry between the developer and the distributor. In some companies, two or all three of these roles may be combined (and indeed, may reside in a single person, especially in the case of shareware).

Software publishers often license software from developers with specifc limitations, such as a time limit or geographical region. Te terms of licensing vary enormously, and are typically secret.

Developers may use publishers to reach larger or foreign markets, or to avoid focussing on marketing. Or publishers may use developers to create software to meet a market need that the publisher has identifed.

Te history of mass media can be traced back to the days when dramas were performed in various ancient cultures. Tis was the frst time when a form of media was "broadcast" to a wider audience. Te frst dated printed book known is the "Diamond Sutra", printed in China in 868 AD, although it is clear that books were printed earlier. Movable clay type was invented in 1041 in China. However, due to the slow spread of literacy to the masses in China, and the relatively high cost

351 of paper there, the earliest printed mass-medium was probably European popular prints from about 1400. Although these were produced in huge numbers, very few early examples survive, and even most known to be printed before about 1600 have not survived. Te term "mass media" was coined with the creation of print media, which is notable for being the frst example of mass media, as we use the term today. Tis form of media started in Europe in the Middle Ages.

Johannes Gutenberg's invention of the printing press allowed the mass production of books to sweep the nation. He printed the frst book, a Latin Bible, on a printing press with movable type in 1453. Te invention of the printing press gave rise to some of the frst forms of mass communication, by enabling the publication of books and newspapers on a scale much larger than was previously possible.[14][15][16] Te invention also transformed the way the world received printed materials, although books remained too expensive really to be called a mass-medium for at least a century after that. Newspapers developed from about 1612, with the frst example in English in 1620;[17] but they took until the 19th century to reach a mass-audience directly. Te frst high-circulation newspapers arose in London in the early 1800s, such as Te Times, and were made possible by the invention of high-speed rotary steam printing presses, and railroads which allowed large-scale distribution over wide geographical areas. Te increase in circulation, however, led to a decline in feedback and interactivity from the readership, making newspapers a more one-way medium.

Te phrase "the media" began to be used in the 1920s.[22] Te notion of "mass media" was generally restricted to print media up until the post-Second World War, when radio, television and video were introduced. Te audio-visual facilities became very popular, because they provided both information and entertainment, because the colour and sound engaged the viewers/listeners and because it was easier for the general public to passively watch TV or listen to the radio than to actively read. In recent times, the Internet become the latest and most popular mass medium. Information has become readily available through websites, and easily accessible through search engines. One can do many activities at the same time, such as playing games, listening to music, and social networking, irrespective of location. Whilst other forms of mass media are restricted in the type of information they can oﬀer, the internet comprises a large percentage of the sum of human knowledge through such things as Google Books. Modern day mass media includes the internet, mobile phones, blogs, podcasts and RSS feeds.[23]

During the 20th century, the growth of mass media was driven by technology, including that which allowed much duplication of material. Physical duplication technologies such as printing, record pressing and flm duplication allowed the duplication of books, newspapers and movies at low prices to huge audiences. Radio and television allowed the electronic duplication of information for the frst time. Mass media had the economics of linear replication: a single work could make money. An example of Riel and Neil's theory. proportional to the number of copies sold, and as volumes went up, unit costs went down, increasing proft margins further. Vast fortunes were to be made in mass media. In a democratic society, the media can serve the electorate about issues regarding government and corporate entities (see Media infuence). Some consider the concentration of media ownership to be a threat to democracy.[24]

Tis section is written like a personal refection, personal essay, or argumentative essay that states a Wikipedia editor's personal feelings or presents an original argument about a topic. Please help improve it by rewriting it in an encyclopedic style. (February 2013) (Learn how and when to remove this template message) Limited-eﬀects theory, originally tested in the 1940s and 1950s, considers that because people usually choose what media to interact with based on what they already believe, media exerts a negligible infuence. Class-dominant theory argues that the media refects and projects the view of a minority elite, which controls it. Culturalist theory, which was developed in the 1980s and 1990s, combines the other two theories and claims that people interact with media to create their own meanings out of the images and messages they receive. Tis theory states that audience members play an active, rather than passive role in relation to mass media.

In an article entitled Mass Media Infuence on Society, rayuso[citation needed] argues that the media in the US is dominated by fve major companies (Time Warner, VIACOM, Vivendi Universal, Walt Disney and News Corp) which own 95% of all mass media including theme parks, movie studios, television and radio broadcast networks and programing, video news, sports entertainment, telecommunications, wireless phones, video games software, electronic media and music companies. Whilst historically, there was more diversity in companies, they have recently merged to form an elite which have the power to shape the opinion and beliefs of people. People buy after seeing thousands of advertisements by various companies in TV, newspapers or magazines, which are able to aﬀect their purchasing decisions. Te defnition of what is acceptable by society is dictated by the media. Tis power can be used for good, for example encouraging children to play sport. However, it can also be used for bad, for example children being infuenced by cigars smoked by flm stars, their exposure to sex images, their exposure to images of violence and their exposure to junk food ads. Te documentary Super Size Me describes how companies like McDonald's have been sued in the past, the plaintiﬀs claiming that it was the fault of their liminal and

352 subliminal advertising that "forced" them to purchase the product. Te Barbie and Ken dolls of the 1950s are sometimes cited as the main cause for the obsession in modern-day society for women to be skinny and men to be buﬀ. After the attacks of 9/11, the media gave extensive coverage of the event and exposed Osama Bin Laden's guilt for the attack, information they were told by the authorities. Tis shaped the public opinion to support the war on terrorism, and later, the war on Iraq. A main concern is that due to this immense power of the mass media (being able to drive the public opinion), media receiving inaccurate information could cause the public opinion to support the wrong cause.

In his book Te Commercialization of American Culture, Matthew P. McAllister says that "a well-developed media system, informing and teaching its citizens, helps democracy move toward its ideal state."[26]

In 1997, J. R. Finnegan Jr. and K. Viswanath identifed 3 main eﬀects or functions of mass media:

Te Knowledge Gap: Te mass media infuences knowledge gaps due to factors including "the extent to which the content is appealing, the degree to which information channels are accessible and desirable, and the amount of social confict and diversity there is in a community". Agenda Setting: People are infuence in how they think about issues due to the selective nature of what media choose for public consumption. After publicly disclosing that he had prostate cancer prior to the 2000 New York senatorial election, Rudolph Giuliani, the mayor of New York City (aided by the media) sparked a huge priority elevation of the cancer in people's consciousness. Tis was because news media began to report on the risks of prostate cancer, which in turn prompted a greater public awareness about the disease and the need for screening. Tis ability for the media to be able to change how the public thinks and behaves has occurred on other occasions. In mid-1970s when Betty Ford and Happy Rockefeller, wives of the then-President and then-Vice President respectively, were both diagnosed with breast cancer. J. J. Davis states that "when risks are highlighted in the media, particularly in great detail, the extent of agenda setting is likely to be based on the degree to which a public sense of outrage and threat is provoked". When wanting to set an agenda, framing can be invaluably useful to a mass media organisation. Framing involves "taking a leadership role in the organisation of public discourse about an issue". Te media is infuenced by the desire for balance in coverage, and the resulting pressures can come from groups with particular political action and advocacy positions. Finnegan and Viswanath say, "groups, institutions, and advocates compete to identify problems, to move them onto the public agenda, and to defne the issues symbolically" (1997, p. 324). Cultivation of Perceptions: Te extent to which media exposure shapes audience perceptions over time is known as cultivation. Television is a common experience, especially in places like the United States, to the point where it can be described as a "homogenising agent" (S. W. Littlejohn). However, instead of being merely a result of the TV, the effect is often based on socioeconomic factors. Having a prolonged exposure to TV or movie violence might affect a viewer to the extent where they actively think community violence is a problem, or alternatively fnd it justifable. Te resulting belief is likely to be different depending of where people live however.[26] Since the 1950s, when cinema, radio and TV began to be the primary or the only source of information for a larger and larger percentage of the population, these media began to be considered as central instruments of mass control.[27][28] Up to the point that it emerged the idea that when a country has reached a high level of industrialization, the country itself "belongs to the person who controls communications."[29]

Mass media play a signifcant role in shaping public perceptions on a variety of important issues, both through the information that is dispensed through them, and through the interpretations they place upon this information.[27] Tey also play a large role in shaping modern culture, by selecting and portraying a particular set of beliefs, values, and traditions (an entire way of life), as reality. Tat is, by portraying a certain interpretation of reality, they shape reality to be more in line with that interpretation.[28] Mass media also play a crucial role in the spread of civil unrest activities such as anti- government demonstrations, riots, and general strikes.[30] Tat is, the use of radio and television receivers has made the unrest infuence among cities not only by the geographic location of cities, but also by proximity within the mass media distribution networks.[30]

Early minstrel shows lampooned the assumed stupidity of black people. Detail from cover of Te Celebrated Negro Melodies, as Sung by the Virginia Minstrels, 1843.

A magazine feature from Beauty Parade from March 1952 stereotyping women drivers. It features Bettie Page as the model.

American political cartoon titled Te Usual Irish Way of Doing Tings, depicting a drunken Irishman lighting a powder keg and swinging a bottle. Published in Harper's Weekly, 1871. ‘Racism’ and stereotyping.

353 Class: Deity highest of being state type. Stereotype. Globe icon. Te examples and perspective in this section may not represent a worldwide view of the subject. You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate. (March 2015) (Learn how and when to remove this template message)

Tis section needs expansion. You can help by adding to it. (December 2012) Mass media sources, through theories like framing and agenda-setting, can aﬀect the scope of a story as particular facts and information are highlighted (Media infuence). Tis can directly correlate with how individuals may perceive certain groups of people, as the only media coverage a person receives can be very limited and may not refect the whole story or situation; stories are often covered to refect a particular perspective to target a specifc demographic.[31]

According to Stephen Balkaran, an Instructor of Political Science and African American Studies at Central Connecticut State University, mass media has played a large role in the way white Americans perceive African-Americans. Te media focus on African-American in the contexts of crime, drug use, gang violence, and other forms of anti-social behavior has resulted in a distorted and harmful public perception of African-Americans. African-Americans have been subjected to oppression and discrimination for the past few hundred years. According to Stephen Balkaran in his article "Mass Media and Racism": "Te media has played a key role in perpetuating the eﬀects of this historical oppression and in contributing to African-Americans' continuing status as second-class citizens". Tis has resulted in an uncertainty among white Americans as to what the genuine nature of African-Americans really is. Despite the resulting racial divide, the fact that these people are undeniably American has "raised doubts about the white man's value system". Tis means that there is a somewhat "troubling suspicion" among some Americans that their white America is tainted by the black infuence.[32] Mass media as well as propaganda tend to reinforce or introduce stereotypes to the general public.

Ethical issues and criticism Lack of local or specifc topical focus is a common criticism of mass media. A mass news media outlet is often forced to cover national and international news due to it having to cater for and be relevant for a wide demographic. As such, it has to skip over many interesting or important local stories because they simply do not interest the large majority of their viewers. An example given by the website WiseGeek is that "the residents of a community might view their fght against development as critical, but the story would only attract the attention of the mass media if the fght became controversial or if precedents of some form were set".[13]

Te term "mass" suggests that the recipients of media products constitute a vast sea of passive, undiﬀerentiated individuals. Tis is an image associated with some earlier critiques of "mass culture" and mass society which generally assumed that the development of mass communication has had a largely negative impact on modern social life, creating a kind of bland and homogeneous culture which entertains individuals without challenging them.[7] However, interactive digital media have also been seen to challenge the read-only paradigm of earlier broadcast media.

Whilst some[who?] refer to the mass media as "opiate of the masses", others[who?] argue that is a vital aspect of human societies. By understanding mass media, one is then able to analyse and fnd a deeper understanding of one's population and culture. Tis valuable and powerful ability is one reason why the feld of media studies is popular. As WiseGeek says, "watching, reading, and interacting with a nation's mass media can provide clues into how people think, especially if a diverse assortment of mass media sources are perused".[13]

Since the 1950s, in the countries that have reached a high level of industrialization, the mass media of cinema, radio and TV have a key role in political power.[29]

Contemporary research demonstrates an increasing level of concentration of media ownership, with many media industries already highly concentrated and dominated by a very small number of frms.[33]

Criticism

When the study of mass media began the media was compiled of only mass media which is a very diﬀerent media system than the social media empire of the 21st-century experiences.[34] With this in mind, there are critiques that mass media no longer exists, or at least that it doesn't exist in the same form as it once did. Tis original form of mass media put flters on what the general public would be exposed to in regards to "news" something that is harder to do in a society of social media. [35]

Teorist Lance Bennett explains that excluding a few major events in recent history, it is uncommon for a group big enough to be labeled a mass, to be watching the same news via the same medium of mass production.[36] Bennett's critique of 21st Century mass media argues that today it is more common for a group of people to be receiving diﬀerent news stories, from

354 completely diﬀerent sources, and thus, mass media has been re-invented. As discussed above, flters would have been applied to original mass medias when the journalists decided what would or wouldn't be printed.

Social Media is a large contributor to the change from mass media to a new paradigm because through social media what is mass communication and what is interpersonal communication is confused.[37] Interpersonal/niche communication is an exchange of information and information in a specifc genre. In this form of communication, smaller groups of people are consuming news/information/opinions. In contrast, mass media in its original form is not restricted by genre and it is being consumed by the masses. Te organizations that control these technologies, such as movie studios, publishing companies, and radio and television stations, are also known as the mass media.[4][5][need quotation to verify]

Sport

Sport includes all forms of competitive physical activity or games which, through casual or organised participation, aim to use, maintain or improve physical ability and skills while providing enjoyment to participants, and in some cases, entertainment for spectators. Usually the contest or game is between two sides, each attempting to exceed the other. Some sports allow a tie game; others provide tie-breaking methods, to ensure one winner and one loser. A number of such two- sided contests may be arranged in a tournament producing a champion. Many sports leagues make an annual champion by arranging games in a regular sports season, followed in some cases by playoﬀs. Hundreds of sports exist, from those between single contestants, through to those with hundreds of simultaneous participants, either in teams or competing as individuals. In certain sports such as racing, many contestants may compete, each against each other, with one winner.

Sport is generally recognised as system of activities which are based in physical athleticism or physical dexterity, with the largest major competitions such as the Olympic Games admitting only sports meeting this defnition, and other organisations such as the Council of Europe using defnitions precluding activities without a physical element from classifcation as sports. However, a number of competitive, but non-physical, activities claim recognition as mind sports. Te International Olympic Committee (through ARISF) recognises both chess and bridge as bona fde sports, and SportAccord, the international sports federation association, recognises fve non-physical sports: bridge, chess, draughts (checkers), Go and xiangqi, and limits the number of mind games which can be admitted as sports.

Sports are usually governed by a set of rules or customs, which serve to ensure fair competition, and allow consistent adjudication of the winner. Winning can be determined by physical events such as scoring goals or crossing a line frst. It can also be determined by judges who are scoring elements of the sporting performance, including objective or subjective measures such as technical performance or artistic impression.

Records of performance are often kept, and for popular sports, this information may be widely announced or reported in sport news. Sport is also a major source of entertainment for non-participants, with spectator sport drawing large crowds to sport venues, and reaching wider audiences through broadcasting. Sports betting is in some cases severely regulated, and in some cases is central to the sport.

According to A.T. Kearney, a consultancy, the global sporting industry is worth up to $620 billion as of 2013. Te world's most accessible and practiced sport is running, while association football is its most popular spectator sport.

Te word "Sport" comes from the Old French desport meaning "leisure", with the oldest defnition in English from around 1300 being "anything humans fnd amusing or entertaining".

Other meanings include gambling and events staged for the purpose of gambling; hunting; and games and diversions, including ones that require exercise. Roget's defnes the noun sport as an "activity engaged in for relaxation and amusement" with synonyms including diversion and recreation.

Te singular term "sport" is used in most English dialects to describe the overall concept (e.g. "children taking part in sport"), with "sports" used to describe multiple activities (e.g. "football and rugby are the most popular sports in England"). American English uses "sports" for both terms.

Te International Olympic Committee recognizes some board games as sports including chess.

Te precise defnition of what separates a sport from other leisure activities varies between sources. Te closest to an international agreement on a defnition is provided by SportAccord, which is the association for all the largest international

355 sports federations (including association football, athletics, cycling, tennis, equestrian sports, and more), and is therefore the de facto representative of international sport.

Sport should have an element of competition be in no way harmful to any living creature not rely on equipment provided by a single supplier (excluding proprietary games such as arena football) not rely on any "luck" element specifcally designed into the sport. Tey also recognise that sport can be primarily physical (such as rugby or athletics), primarily mind (such as chess or go), predominantly motorised (such as Formula 1 or powerboating), primarily co-ordination (such as billiard sports), or primarily animal-supported (such as equestrian sport).

Te inclusion of mind sports within sport defnitions has not been universally accepted, leading to legal challenges from governing bodies in regards to being denied funding available to sports. Whilst SportAccord recognises a small number of mind sports, it is not open to admitting any further mind sports.

Tere has been an increase in the application of the term "sport" to a wider set of non-physical challenges such as video games, also called esports, especially due to the large scale of participation and organised competition, but these are not widely recognised by mainstream sports organisations. According to Council of Europe, European Sports Charter, article 2.i, " "Sport" means all forms of physical activity which, through casual or organised participation, aim at expressing or improving physical ftness and mental well-being, forming social relationships or obtaining results in competition at all levels.".

Tere are opposing views on the necessity of competition as a defning element of a sport, with almost all professional sport involving competition, and governing bodies requiring competition as a prerequisite of recognition by the International Olympic Committee (IOC) or SportAccord.

Other bodies advocate widening the defnition of sport to include all physical activity. For instance, the Council of Europe include all forms of physical exercise, including those competed just for fun.

In order to widen participation, and reduce the impact of losing on less able participants, there has been an introduction of non-competitive physical activity to traditionally competitive events such as school sports days, although moves like this are often controversial.

In competitive events, participants are graded or classifed based on their "result" and often divided into groups of comparable performance, (e.g. gender, weight and age). Te measurement of the result may be objective or subjective, and corrected with "handicaps" or penalties. In a race, for example, the time to complete the course is an objective measurement. In gymnastics or diving the result is decided by a panel of judges, and therefore subjective. Tere are many shades of judging between boxing and mixed martial arts, where victory is assigned by judges if neither competitor has lost at the end of the match time.

Roman bronze reduction of Myron's Discobolos, 2nd century AD. Artifacts and structures suggest sport in China as early as 2000 BC. Gymnastics appears to have been popular in China's ancient past. Monuments to the Pharaohs indicate that a number of sports, including swimming and fshing, were well-developed and regulated several thousands of years ago in ancient Egypt. Other Egyptian sports included javelin throwing, high jump, and wrestling. Ancient Persian sports such as the traditional Iranian martial art of Zourkhaneh had a close connection to warfare skills. Among other sports that originate in ancient Persia are polo and jousting.

Motorized sports have appeared since the advent of the modern age. Electronic sports are a recent development. A wide range of sports were already established by the time of Ancient Greece and the military culture and the development of sports in Greece infuenced one another considerably. Sports became such a prominent part of their culture that the Greeks created the Olympic Games, which in ancient times were held every four years in a small village in the Peloponnesus called Olympia.

Sports have been increasingly organised and regulated from the time of the ancient Olympics up to the present century. Industrialisation has brought increased leisure time, letting people attend and follow spectator sports and participate in athletic activities. Tese trends continued with the advent of mass media and global communication. Professionalism became prevalent, further adding to the increase in sport's popularity, as sports fans followed the exploits of professional athletes — all while enjoying the exercise and competition associated with amateur participation in sports. Since the turn of the 21st century, there has been increasing debate about whether transgender sportpersons should be able to participate in sport events that conform with their post-transition gender identity.

356 Gamesmanship and Winning isn't everything; it's the only thing, Sportsmanship is an attitude that strives for fair play, courtesy toward teammates and opponents, ethical behaviour and integrity, and grace in victory or defeat. To in losing you can still learn things.

Sportsmanship expresses an aspiration or ethos that the activity will be enjoyed for its own sake. Te well-known sentiment by sports journalist Grantland Rice, that it's "not that you won or lost but how you played the game", and the modern Olympic creed expressed by its founder Pierre de Coubertin: "Te most important thing... is not winning but taking part" are typical expressions of this sentiment.

Key principles of sport include that the result should not be predetermined, and that both sides should have equal opportunity to win. Rules are in place to ensure that fair play to occur, but participants can break these rules in order to gain advantage.

Participants may choose to cheat in order to satisfy their desire to win, or in order to achieve an ulterior motive. Te widespread existence of gambling on the results of sports fxtures creates the motivation for match fxing, where a participant or participants deliberately work to ensure a given outcome.

Te competitive nature of sport encourages some participants to attempt to enhance their performance through the use of medicines, or through other means such as increasing the volume of blood in their bodies through artifcial means.

All sports recognised by the IOC or SportAccord are required to implement a testing programme, looking for a list of banned drugs, with suspensions or bans being placed on participants who test positive for banned substances.

Violence in sports involves crossing the line between fair competition and intentional aggressive violence. Athletes, coaches, fans, and parents sometimes unleash violent behaviour on people or property, in misguided shows of loyalty, dominance, anger, or celebration. Rioting or hooliganism by fans in particular is a problem at some national and international sporting contests.

International level women athletes at ISTAF Berlin, 2006

Women's sports, Women's professional sports, and Women's sports in the United States Female participation in sports continues to rise alongside the opportunity for involvement and the value of sports for child development and physical ftness. Despite gains during the last three decades, a gap persists in the enrollment fgures between male and female players. Female players account for 39% of the total participation in US interscholastic athletics. Gender balance has been accelerating from a 32% increase in 1973–74 to a 63% increase in 1994–95.

Youth sports present children with opportunities for fun, socialization, forming peer relationships, physical ftness, and athletic scholarships. Activists for education and the war on drugs encourage youth sports as a means to increase educational participation and to fght the illegal drug trade. According to the Center for Injury Research and Policy at Nationwide Children's Hospital, the biggest risk for youth sports is death or serious injury including concussion. Tese risks come from running, basketball, association football, volleyball, gridiron, gymnastics, and ice hockey. Youth sports in the US is a $15 billion industry including equipment up to private coaching.

Disabled participation

A runner gives a friendly tap on the shoulder to a wheelchair racer during the Marathon International de Paris (Paris Marathon) in 2014. Disabled sports also adaptive sports or parasports, are sports played by persons with a disability, including physical and intellectual disabilities. As many of these based on existing sports modifed to meet the needs of persons with a disability, they are sometimes referred to as adapted sports. However, not all disabled sports are adapted; several sports that have been specifcally created for persons with a disability have no equivalent in able-bodied sports.

Te competition element of sport, along with the aesthetic appeal of some sports, result in the popularity of people attending to watch sport being played. Tis has led to the specifc phenomenon of spectator sport.

Both amateur and professional sports attract spectators, both in person at the sport venue, and through broadcast media including radio, television and internet broadcast. Both attendance in person and viewing remotely can incur a sometimes substantial charge, such as an entrance ticket, or pay-per-view television broadcast.

It is common for popular sports to attract large broadcast audiences, leading to rival broadcasters bidding large amounts of money for the rights to show certain fxtures. Te football World Cup attracts a global television audience of hundreds of

357 millions; the 2006 fnal alone attracted an estimated worldwide audience of well over 700 million and the 2011 Cricket World Cup Final attracted an estimated audience of 135 million in India alone .

Sport can be undertaken on an amateur, professional or semi-professional basis, depending on whether participants are incentivised for participation (usually through payment of a wage or salary). Amateur participation in sport at lower levels is often called "grassroots sport".

Te popularity of spectator sport as a recreation for non-participants has led to sport becoming a major business in its own right, and this has incentivised a high paying professional sport culture, where high performing participants are rewarded with pay far in excess of average wages, which can run into millions of dollars.

Some sports, or individual competitions within a sport, retain a policy of allowing only amateur sport. Te Olympic Games started with a principle of amateur competition with those who practiced a sport professionally considered to have an unfair advantage over those who practiced it merely as a hobby. From 1971, Olympic athletes were allowed to receive compensation and sponsorship, and from 1986, the IOC decided to make all professional athletes eligible for the Olympics, with the exceptions of boxing, and wrestling.

Technology plays an important part in modern sports. With it being a necessary part of some sports (such as motorsport), it is used in others to improve performance. Some sports also use it to allow oﬀ-feld decision making.

Sports science is a widespread academic discipline, and can be applied to areas including athlete performance, such as the use of video analysis to fne-tune technique, or to equipment, such as improved running shoes or competitive swimwear. Sports engineering emerged as a discipline in 1998 with an increasing focus not just on materials design but also the use of technology in sport, from analytics and big data to wearable technology. In order to control the impact of technology on fair play, governing bodies frequently have specifc rules that are set to control the impact of technical advantage between participants. For example, in 2010, full-body, non-textile swimsuits were banned by FINA, as they were enhancing swimmers' performances.

Te increase in technology has also allowed many decisions in sports matches to be taken, or reviewed, off-feld, with another official using instant replays to make decisions. In some sports, players can now challenge decisions made by officials. In football, Goal-line technology makes decisions on whether a ball has crossed the goal line or not. Te technology is not compulsory, but was used in the 2014 FIFA World Cup in Brazil, and the 2015 FIFA Women's World Cup in Canada, as well as in the Premier League from 2013–14, and the Bundesliga from 2015–16. In the NFL, a referee can ask for a review from the replay booth, or a head coach can issue a challenge to review the play using replays. Te fnal decision rests with the referee. A video referee (commonly known as a Television Match Official or TMO) can also use replays to help decision-making in rugby (both league and union). In international cricket, an umpire can ask the Tird umpire for a decision, and the third umpire makes the fnal decision. Since 2008, a decision review system for players to review decisions has been introduced and used in ICC-run tournaments, and optionally in other matches. Depending on the host broadcaster, a number of different technologies are used during an umpire or player review, including instant replays, Hawk- Eye, Hot Spot and Real Time Snickometer. Hawk-Eye is also used in tennis to challenge umpiring decisions.

Festivals and Carnivals

A festival is an event ordinarily celebrated by a community and centering on some characteristic aspect of that community and its religion or traditions. It is often marked as a local or national holiday, mela, or eid. Next to religion and folklore, a signifcant origin is agricultural. Food is such a vital resource that many festivals are associated with harvest time. Religious commemoration and thanksgiving for good harvests are blended in events that take place in autumn, such as Halloween in the northern hemisphere and Easter in the southern.

Festivals often serve to fulfll specifc communal purposes, especially in regard to commemoration or thanksgiving. Te celebrations oﬀer a sense of belonging for religious, social, or geographical groups, contributing to group cohesiveness. Tey may also provide entertainment, which was particularly important to local communities before the advent of mass-produced entertainment. Festivals that focus on cultural or ethnic topics also seek to inform community members of their traditions; the involvement of elders sharing stories and experience provides a means for unity among families.

In Ancient Greece and Rome, festivals such as the Saturnalia were closely associated with social organisation and political processes as well as religion. In modern times, festivals may be attended by strangers such as tourists, who are attracted to some of the more eccentric or historical ones.

358 Te word "festival" was originally used as an adjective from the late fourteenth century, deriving from Latin via Old French. In Middle English, a "festival dai" was a religious holiday. Its frst recorded used as a noun was in 1589 (as "Festifall"). Feast frst came into usage as a noun circa 1200, and its frst recorded use as a verb was circa 1300. Te term "feast" is also used in common secular parlance as a synonym for any large or elaborate meal. When used as in the meaning of a festival, most often refers to a religious festival rather than a flm or art festival. In the Philippines and many other former Spanish colonies, the Spanish word festa is used to denote a communal religious feast to honor a patron saint.

Carnival (see other spellings and names) is a Western Christian festive season that occurs before the liturgical season of Lent. Te main events typically occur during February or early March, during the period historically known as Shrovetide (or Pre- Lent). Carnival typically involves a public celebration or parade combining some elements of a circus, masks, and a public street party. People wear masks and costumes during many such celebrations, allowing them to lose their everyday individuality and experience a heightened sense of social unity. Excessive consumption of alcohol, meat, and other foods proscribed during Lent is extremely common. Other common features of carnival include mock battles such as food fghts; social satire and mockery of authorities; the grotesque body displaying exaggerated features, especially large noses, bellies, mouths, and phalli, or elements of animal bodies; abusive language and degrading acts; depictions of disease and gleeful death; and a general reversal of everyday rules and norms.

Te term Carnival is traditionally used in areas with a large Catholic presence. However, the Philippines, a predominantly Roman Catholic country, does not celebrate Carnival (or Mardi Gras) anymore since the dissolution of the Manila Carnival after 1939, the last carnival in the country. In historically Evangelical Lutheran countries, the celebration is known as Fastelavn, and in areas with a high concentration of Anglicans (Church of England / Episcopal Church in the U.S.A.), Methodists, and other Protestants, pre-Lenten celebrations, along with penitential observances, occur on Shrove Tuesday. In Slavic Eastern Orthodox nations, Maslenitsa is celebrated during the last week before Great Lent. In German-speaking Europe and the Netherlands, the Carnival season traditionally opens on 11/11 (often at 11:11 a.m.). Tis dates back to celebrations before the Advent season or with harvest celebrations of St. Martin's Day.[citation needed]

God stated to Abrademus that before decent to Earth everyone is trained in a specifc profession whether it be in analysing Orbs, too Account Execs, Doctor’s, Lawyers, Soldiers/Police, Politicians, Truthologists, Algologists, Quellers, Prophets, usually bright children are told by god, they’re own spiritual souls our even by themselves what profession they are suited for, if people get this right - upon returning to heaven they’re god congratulates them and thanks them for they’re work and for sticking too they’re tasks - the only time this can be a mix up is when war’s happen - everything becomes confused. When god inherits the Earth so do his people, with understanding comes everything else- an infused society and culture, everything blooms.

10), Fashion, Art, Design and Craft

Fashion is visual language is a system of communication using visual elements. Speech as a means of communication cannot strictly be separated from the whole of human communicative activity which includes the visual[1] and the term 'language' in relation to vision is an extension of its use to describe the perception, comprehension and production of visible signs.

An image which dramatizes and communicates an idea presupposes the use of a visual language. Just as people can 'verbalize' their thinking, they can 'visualize' it. A diagram, a map, and a painting are all examples of uses of visual language. Its structural units include line, shape, colour, form, motion, texture, pattern, direction, orientation, scale, angle, space and proportion.

Te elements in an image represent concepts in a spatial context, rather than the linear form used for words. Speech and visual communication are parallel and often interdependent means by which humans exchange information.

Visual language Visual units in the form of lines and marks are constructed into meaningful shapes and structures or signs. Diﬀerent areas of the cortex respond to diﬀerent elements such as colour and form. Semir Zeki[2] has shown the responses in the brain to the paintings of Michelangelo, Rembrandt, Vermeer, Magritte, Malevich and Picasso.

359 Fashion

Fashion is a style or practice, especially prominent in visual culture especially clothing, footwear, accessories, makeup, hairstyle and body. Fashion is a distinctive and often constant trend in the style in which a person dresses. It is the prevailing styles in behaviour and the newest creations of textile designers.Because the more technical term costume is regularly linked to the term "fashion", the use of the former has been relegated to special senses like fancy dress or masquerade wear, while "fashion" generally means clothing, including the study of it. Although aspects of fashion can be feminine or masculine, some trends are androgynous.

Early travelers, traveling whether to India, Persia, Turkey or China, would frequently remark on the absence of change in fashion in those countries. Te Japanese shōgun's secretary bragged (not completely accurately) to a Spanish visitor in 1609 that Japanese clothing had not changed in over a thousand years.[3] However, there is considerable evidence in Ming China of rapidly changing fashions in Chinese clothing.[4] Changes in costume often took place at times of economic or social change, as occurred in ancient Rome and the medieval Caliphate, followed by a long period without major changes. In 8th-century Moorish Spain, the musician Ziryab introduced to Córdoba[5][unreliable source][6] sophisticated clothing- styles based on seasonal and daily fashions from his native Baghdad, modifed by his own inspiration. Similar changes in fashion occurred in the 11th century in the Middle East following the arrival of the Turks, who introduced clothing styles from Central Asia and the Far East.[7

In the 16th century, national differences were at their most pronounced. Ten 16th century portraits of German or Italian gentlemen may show ten entirely different hats. Albrecht Dürer illustrated the differences in his actual (or composite) contrast of Nuremberg and Venetian fashions at the close of the 15th century (illustration, right). Te "Spanish style" of the late 16th century began the move back to synchronicity among upper-class Europeans, and after a struggle in the mid-17th century, French styles decisively took over leadership, a process completed in the 18th century.[15]

Tough diﬀerent textile colors and patterns changed from year to year,[16] the cut of a gentleman's coat and the length of his waistcoat, or the pattern to which a lady's dress was cut, changed more slowly. Men's fashions were largely derived from military models, and changes in a European male silhouette were galvanized in theaters of European war where gentleman oﬃcers had opportunities to make notes of foreign styles such as the "Steinkirk" cravat or necktie.

Marie Antoinette, wife of Louis XVI, was a leader of fashion. Her choices, such as this 1783 white muslin dress called a chemise a la Reine, were highly infuential and widely worn.[17]

Tough there had been distribution of dressed dolls from France since the 16th century and Abraham Bosse had produced engravings of fashion in the 1620s, the pace of change picked up in the 1780s with increased publication of French engravings illustrating the latest Paris styles. By 1800, all Western Europeans were dressing alike (or thought they were); local variation became frst a sign of provincial culture and later a badge of the conservative peasant.[18]

Although tailors and dressmakers were no doubt responsible for many innovations, and the textile industry certainly led many trends, the history of fashion design is normally understood to date from 1858 when the English-born Charles Frederick Worth opened the frst true haute couture house in Paris. Te Haute house was the name established by government for the fashion houses that met the standards of industry. Tese fashion houses have to adhere to standards such as keeping at least twenty employees engaged in making the clothes, showing two collections per year at fashion shows, and presenting a certain number of patterns to costumers.[19] Since then, the idea of the fashion designer as a celebrity in his or her own right has become increasingly dominant.[20]

360 Political infuence

Moreover, political movement built an impressive relationship with fashion trend. For instance, during Vietnam war, the youth of America made a movement that aﬀected the whole country. In the 1960s, the fashion trend was full of fuorescent colors, prints patterns, bell-bottom jeans, fringed vests, and skirt became a protest outft of the 1960s. Tis trend was called Hippie and it is still aﬀecting current fashion trend.[29

Developments such as wearable technology have become an important trend in fashion and will continue with advances such as clothing constructed with solar panels that charge devices and smart fabrics that enhance wearer comfort by changing color or texture based on environmental changes.[3

Te military has played an important role in the fashion industry. Te camoufage pattern in clothing was developed to help military personnel be less visible to enemy forces. A trend emerged in the 1960s and camoufage fabric was introduced to street wear. Te camoufage fabric trend disappeared and resurfaced several times since then. Camoufage started to appear in high fashion by the 1990s.Designers such as Valentino, Dior and Dolce & Gabbana combined camoufage into their runway and ready-to-wear collections.

Fashion relates to social and cultural context of an environment. According to Matika,[35] "Elements of popular culture become fused when a person's trend is associated with a preference for a genre of music...like music, news or literature, fashion has been fused into everyday lives." Fashion is not only seen as pure aesthetic values; fashion is also a medium for performers to create an overall atmosphere and express their opinions altogether through music video. Te latest music video ‘Formation’ by Beyoncé, according to Carlos,[36] "Te pop star pays homage to her Creole root.... tracing the roots of the Louisiana cultural nerve center from the post-abolition era to present day, Beyoncé catalogs the evolution of the city's vibrant style and its tumultuous history all at once. Atop a New Orleans police car in a red-and-white Gucci high-collar dress and combat boots, she sits among the ruins of Hurricane Katrina, immediately implanting herself in the biggest national debate on police brutality and race relations in those days."

Knowing the needs of the consumers will increase a fashion companies' sales and profts. Trough research and studying the consumers' lives the needs of the customer can be obtained and help fashion brands know what trends the consumers are ready for.

Latin dancers in their costumes. Te woman is wearing backless dress with deep slits on its lower portion, while the man is wearing a shirt with top buttons open. Te media plays a signifcant role when it comes to fashion. For instance, an important part of fashion is fashion journalism. Editorial critique, guidelines, and commentary can be found on television and in magazines, newspapers, fashion websites, social networks, and fashion blogs. In recent years, fashion blogging and

YouTube videos have become a major outlet for spreading trends and fashion tips, creating an online culture of sharing one's style on a website or Instagram account. Trough these media outlets readers and viewers all over the world can learn about fashion, making it very accessible.[44]

At the beginning of the 20th century, fashion magazines began to include photographs of various fashion designs and became even more infuential than in the past.[45] In cities throughout the world these magazines were greatly sought after and had a profound eﬀect on public taste in clothing. Talented illustrators drew exquisite fashion plates for the publications which covered the most recent developments in fashion and beauty. Perhaps the most famous of these magazines was La Gazette du Bon Ton, which was founded in 1912 by Lucien Vogel and regularly published until 1925 (with the exception of the war years).[46]

A see-through top worn along with pasties by a model at a fashion show in USA, 2017. Such fashion trends get popularised through media. Vogue, founded in the United States in 1892, has been the longest-lasting and most successful of the hundreds of fashion magazines that have come and gone. Increasing aﬄuence after World War II and, most importantly, the advent of cheap color printing in the 1960s, led to a huge boost in its sales and heavy coverage of fashion in mainstream

361 women's magazines, followed by men's magazines in the 1990s. One such example of Vogue's popularity is the younger version, Teen Vogue, which covers clothing and trends that are targeted more toward the "fashionista on a budget". Haute couture designers followed the trend by starting ready-to-wear and perfume lines which are heavily advertised in the magazines and now dwarf their original couture businesses. A recent development within fashion print media is the rise of text-based and critical magazines which aim to prove that fashion is not superfcial, by creating a dialogue between fashion academia and the industry. Examples of this trend are: Fashion Teory (1997) and Vestoj (2009). Television coverage began in the 1950s with small fashion features. In the 1960s and 1970s, fashion segments on various entertainment shows became more frequent, and by the 1980s, dedicated fashion shows such as Fashion Television started to appear. FashionTV was the pioneer in this undertaking and has since grown to become the leader in both Fashion Television and new media channels. Te Fashion Industry is beginning to promote their styles through Bloggers on social media's. Vogue specifed Chiara Ferragni as "blogger of the moment" due to the rises of followers through her Fashion Blog, that became popular.[47]

A few days after the 2010 Fall Fashion Week in New York City came to a close, Te New Islander's Fashion Editor, Genevieve Tax, criticized the fashion industry for running on a seasonal schedule of its own, largely at the expense of real- world consumers. "Because designers release their fall collections in the spring and their spring collections in the fall, fashion magazines such as Vogue always and only look forward to the upcoming season, promoting parkas come September while issuing reviews on shorts in January", she writes. "Savvy shoppers, consequently, have been conditioned to be extremely, perhaps impractically, farsighted with their buying."[48]

Te fashion industry has been the subject of numerous flms and television shows, including the reality show Project Runway and the drama series Ugly Betty. Specifc fashion brands have been featured in flm, not only as product placement opportunities, but as bespoke items that have subsequently led to trends in fashion.[49]

Videos in general have been very useful in promoting the fashion industry. Tis is evident not only from television shows directly spotlighting the fashion industry, but also movies, events and music videos which showcase fashion statements as well as promote specifc brands through product placements.

Fashion public relations involves being in touch with a company's audiences and creating strong relationships with them, reaching out to media and initiating messages that project positive images of the company.[50] Social media plays an important role in modern-day fashion public relations; enabling practitioners to reach a wide range of consumers through various platforms.[51]

Building brand awareness and credibility is a key implication of good public relations. In some cases, great hype is built about new designers' collections before they are released into the market, due to the immense exposure generated by practitioners.[52] Social media, such as blogs, micro blogs, podcasts, photo and video sharing sites have all become increasingly important to fashion public relations.[53] Te interactive nature of these platforms allows practitioners to engage and communicate with the public in real time, and tailor their clients' brand or campaign messages to the target audience. With blogging platforms such as Instagram, Tumblr, Wordpress, and other sharing sites, bloggers have emerged as expert fashion commentators, shaping brands and having a great impact on what is ‘on trend’.[54] Women in the fashion public relations industry such as Sweaty Betty PR founder Roxy Jacenko and Oscar de la Renta's PR girl Erika

Bearman, have acquired copious followers on their social media sites, by providing a brand identity and a behind the scenes look into the companies they work for.

Social media is changing the way practitioners deliver messages,[12] as they are concerned with the media, and also customer relationship building.[55] PR practitioners must provide eﬀective communication among all platforms, in order to engage the fashion public in an industry socially connected via online shopping.[56] Consumers have the ability to share their purchases on their personal social media pages (such as Facebook, Twitter, Instagram, etc.), and if practitioners deliver the brand message eﬀectively and meet the needs of its public, word-of-mouth publicity will be generated and potentially provide a wide reach for the designer and their products.

Anthropology, the study of culture and human societies, studies fashion by asking why certain styles are deemed socially appropriate and others are not. A certain way is chosen and that becomes the fashion as defned by a certain people as a

362 whole, so if a particular style has a meaning in an already occurring set of beliefs that style will become fashion. According to Ted Polhemus and Lynn Procter, fashion can be described as adornment, of which there are two types: fashion and anti- fashion. Trough the capitalization and commoditisation of clothing, accessories, and shoes, etc., what once constituted anti-fashion becomes part of fashion as the lines between fashion and anti-fashion are blurred

Te defnition of fashion and anti-fashion is as follows: Anti-fashion is fxed and changes little over time. Anti-fashion is diﬀerent depending on the cultural or social group one is associated with or where one lives, but within that group or locality the style changes little. Fashion is the exact opposite of anti-fashion. Fashion changes very quickly and is not aﬃliated with one group or area of the world but is spread out throughout the world wherever people can communicate easily with each other. For example, Queen Elizabeth II's 1953 coronation gown is an example of anti-fashion because it is traditional and does not change over any period whereas a gown from fashion designer Dior's collection of 1953 is fashion because the style will change every season as Dior comes up with a new gown to replace the old one. In the Dior gown the length, cut, fabric, and embroidery of the gown change from season to season. Anti-fashion is concerned with maintaining the status quo while fashion is concerned with social mobility. Time is expressed in terms of continuity in anti-fashion and as change in fashion. Fashion has changing modes of adornment while anti-fashion has fxed modes of adornment. Indigenous and peasant modes of adornment are an example of anti-fashion. Change in fashion is part of the larger system and is structured to be a deliberate change in style.[59]

Today, people in rich countries are linked to people in poor countries through the commoditization and consumption of what is called fashion. People work long hours in one area of the globe to produce things that people in another part of the globe are anxious to consume. An example of this is the chain of production and consumption of Nike shoes, which are produced in Taiwan and then purchased in North America. At the production end, there is nation-building a hard working ideology that leads people to produce and entices people to consume with a vast amount of goods for the oﬀering[clarifcation needed]. Commodities are no longer just utilitarian but are fashionable, be they running shoes or sweat suits.[60

Te change from anti-fashion to fashion because of the infuence of western consumer-driven civilization can be seen in eastern Indonesia. Te ikat textiles of the Ngada area of eastern Indonesia are changing because of modernization and development. Traditionally, in the Ngada area there was no idea similar to that of the Western idea of fashion, but anti- fashion in the form of traditional textiles and ways to adorn oneself were widely popular. Textiles in Indonesia have played many roles for the local people. Textiles defned a person's rank and status; certain textiles indicated being part of the ruling class. People expressed their ethnic identity and social hierarchy through textiles. Because some Indonesians bartered ikat textiles for food, the textiles constituted economic goods, and as some textile design motifs had spiritual religious meanings, textiles were also a way to communicate religious messages.[61]

In eastern Indonesia, both the production and use of traditional textiles have been transformed as the production, use and value associated with textiles have changed due to modernization. In the past, women produced the textiles either for home consumption or to trade with others. Today, this has changed as most textiles are not being produced at home. Western goods are considered modern and are valued more than traditional goods, including the sarong, which retain a lingering association with colonialism. Now, sarongs are used only for rituals and ceremonial occasions, whereas western clothes are worn to church or government offices. Civil servants working in urban areas are more likely than peasants to make the distinction between western and traditional clothes. Following Indonesia's independence from the Dutch, people increasingly started buying factory made shirts and sarongs. In textile-producing areas the growing of cotton and production of naturally colored thread became obsolete. Traditional motifs on textiles are no longer considered the property of a certain social class or age group. Wives of government officials are promoting the use of traditional textiles in the form of western garments such as skirts, vests and blouses. Tis trend is also being followed by the general populace, and whoever can afford to hire a tailor is doing so to stitch traditional ikat textiles into western clothes. Tus, traditional textiles are now fashion goods and are no longer confned to the black, white and brown colour palette but come in array of colours. Traditional textiles are also being used in interior decorations and to make handbags, wallets and other accessories, which are considered fashionable by civil servants and their families. Tere is also a booming tourist trade in the eastern Indonesian city of Kupang where international as well as domestic tourists are eager to purchase traditionally printed western goods.[62]

Te use of traditional textiles for fashion is becoming big business in eastern Indonesia, but these traditional textiles are losing their ethnic identity markers and are being used as an item of fashion.[63]

Political activism

363 Tere has been great debate about politics' place in fashion and traditionally, the fashion industry has maintained a rather apolitical stance.[67] Considering the U.S.'s political climate in the surrounding months of the 2016 presidential election, during 2017 fashion weeks in London, Milan, New York, Paris and São Paulo amongst others, many designers took the opportunity to take political stances leveraging their platforms and infuence to reach the masses.

Aiming to “amplify a greater message of unity, inclusion, diversity, and feminism in a fashion space”, Mara Hoﬀma invited the founders of the Women's March on Washington to open her show which featured modern silhouettes of utilitarian wear, described by critics as “Made for a modern warrior” and “Clothing for those who still have work to do”.[70] Prabal Gurung debuted his collection of T-shirts featuring slogans such as “Te Future is Female”, “We Will Not Be Silenced”, and “Nevertheless She Persisted”, with proceeds going to the ACLU, Planned Parenthood, and Gurung's own charity, “Shikshya Foundation Nepal”.[67] Similarly, Te Business of Fashion launched the #TiedTogether movement on Social Media, encouraging member of the industry from editors to models, to wear a white bandana advocating for “unity, solidarity, and inclusiveness during fashion week”.[71]

Fashion may be used to promote a cause, such as to promote healthy behavior,[72] to raise money for a cancer cure,[73] or to raise money for local charities[74] such as the Juvenile Protective Association[75] or a children's hospice.[

One fashion cause is trashion, which is using trash to make clothes, jewelry, and other fashion items in order to promote awareness of pollution. Tere are a number of modern trashion artists such as Marina DeBris, Ann Wizer,[77] and Nancy Judd.[78]

A textile[1] is a fexible material consisting of a network of natural or artifcial fbers (yarn or thread). Yarn is produced by spinning raw fbres of wool, fax, cotton, hemp, or other materials to produce long strands.[2] Textiles are formed by weaving, knitting, crocheting, knotting or tatting, felting, or braiding.

Te related words "fabric"[3] and "cloth"[4] and "material" are often used in textile assembly trades (such as tailoring and dressmaking) as synonyms for textile. However, there are subtle diﬀerences in these terms in specialized usage. A textile is any material made of interlacing fbres, including carpeting and geotextiles. A fabric is a material made through weaving, knitting, spreading, crocheting, or bonding that may be used in production of further goods (garments, etc.). Cloth may be used synonymously with fabric but is often a piece of fabric that has been processed.

Weaving is a method of textile production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. Other methods are knitting, crocheting, felting, and braiding or plaiting. Te longitudinal threads are called the warp and the lateral threads are the weft or flling. (Weft is an old English word meaning "that which is woven"; compare leave and left.[a]) Te method in which these threads are inter-woven aﬀects the characteristics of the cloth.[1] Cloth is usually woven on a loom, a device that holds the warp threads in place while flling threads are woven through them. A fabric band which meets this defnition of cloth (warp threads with a weft thread winding between) can also be made using other methods, including tablet weaving, back strap loom, or other techniques without looms.[2]

Te way the warp and flling threads interlace with each other is called the weave. Te majority of woven products are created with one of three basic weaves: plain weave, satin weave, or twill. Woven cloth can be plain (in one colour or a simple pattern), or can be woven in decorative or artistic design.

A loom is a device used to weave cloth and tapestry. Te basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads. Te precise shape of the loom and its mechanics may vary, but the basic function is the same.

Te Loom is a symbol of cosmic creation and the structure upon which individual destiny is woven. Tis symbolism is encapsulated in the ancient Greek myth of Arachne who was changed into a spider by the goddess Athene, who was jealous of her skill at the godlike craft of weaving.[25] In Maya Cultures the goddess Ixchel who is symbolized by the moon, taught the frst woman how to weave at the beginning of time.[26]

Te Jacquard machine (French: [ʒakaʁ]) is a device ftted to a power loom that simplifes the process of manufacturing textiles with such complex patterns as brocade, damask and matelassé.[3] It was invented by Joseph Marie Jacquard in 1804. [4] Te loom was controlled by a "chain of cards"; a number of punched

364 cards laced together into a continuous sequence.[5] Multiple rows of holes were punched on each card, with one complete card corresponding to one row of the design. Several such paper cards, generally white in color, can be seen in the images below. Chains, like Bouchon's earlier use of paper tape, allowed sequences of any length to be constructed, not limited by the size of a card.

It is based on earlier inventions by the Frenchmen Basile Bouchon (1725), Jean Baptiste Falcon (1728), and Jacques Vaucanson (1740).[6] A static display of a Jacquard loom is the centrepiece of the Musée des Tissus et des Arts décoratifs in Lyon.[7] Live displays of a Jacquard loom are available at a few private museums around Lyon and also twice a day at La Maison des Canuts, as well as at other locations around the world.

Both the Jacquard process and the necessary loom attachment are named after their inventor. Tis mechanism is probably one of the most important weaving inventions as Jacquard shedding made possible the automatic production of unlimited varieties of pattern weaving. Te term "Jacquard" is not specifc or limited to any particular loom, but rather refers to the added control mechanism that automates the patterning. Te process can also be used for patterned knitwear and machine- knitted textiles, such as jerseys.[8]

Tis use of replaceable punched cards to control a sequence of operations is considered an important step in the history of computing hardware.

Fashion is showing the feelings you emote usually through cloth and textiles tho other objects and visual qualia too. Its is prominent most too culture.

What we have in our minds in a waking state and what we imagine in dreams is very much of the same nature.[3] Dream images might be with or without spoken words, other sounds or colours. In the waking state there is usually, in the foreground, the buzz of immediate perception, feeling, mood and as well as feeting memory images.[4] In a mental state between dreaming and being fully awake is a state known as 'day dreaming' or a meditative state, during which "the things we see in the sky when the clouds are drifting, the centaurs and stags, antelopes and wolves" are projected from the imagination.[5] Rudolf Arnheim[6] has attempted to answer the question: what does a mental image look like? In Greek philosophy, the School of Leucippus and Democritus believed that a replica of an object enters the eye and remains in the soul as a memory as a complete image. Berkeley explained that parts, for example, a leg rather than the complete body, can be brought visually to the mind. Arnheim considers the psychologist, Edward B. Titchener's account to be the breakthrough in understanding something of how the vague incomplete quality of the image is 'impressionistic' and carries meaning as well as form.

Meaning and expression Abstract art has shown that the qualities of line and shape, proportion and colour convey meaning directly without the use of words or pictorial representation. Wassily Kandinsky[7] showed how drawn lines and marks can be expressive without any association with a representational image. From the most ancient cultures and throughout history visual language has been used to encode meaning: "Te Bronze Age Badger Stone on Ilkly Moor is covered in circles, lines, hollow cups,winged fgures, a spread hand, an ancient swastika, an embryo, a shooting star? ... It's a story-telling rock, a message from a world before (written) words."[8] Richard Gregory suggests that, "Perhaps the ability to respond to absent imaginary situations," as our early ancestors did with paintings on rock, "represents an essential step towards the development of abstract thought."[9]

Perception Te sense of sight operates selectively. Perception is not a passive recording of all that is in front of the eyes, but is a continuous judgement of scale and colour relationships,[10] and includes making categories of forms to classify images and shapes in the world.[11] Children of six to twelve months are to be able through experience and learning to discriminate between circles, squares and triangles.Te child from this age onwards learns to classify objects, abstracting essential qualities and comparing them to other similar objects. Before objects can be perceived and identifed the child must be able to classify the diﬀerent shapes and sizes that a single object may appear to have when it is seen in varying surroundings and from diﬀerent aspects.[12]

Innate structures in the brain Te perception of a shape requires the grasping of the essential structural features, to produce a "whole" or gestalt. Te theory of the gestalt was proposed by Christian von Ehrenfels in 1890. He pointed out that a melody is still recognisable when played in diﬀerent keys and argued that the whole is not simply the sum of its parts but a total structure. Max Wertheimer researched von Ehrenfels' idea, and in his "Teory of Form" (1923) – nicknamed "the dot essay" because it was illustrated with abstract patterns of dots and lines – he concluded that the perceiving eye tends to bring together elements that look alike (similarity groupings) and will complete an incomplete form (object hypothesis). An array of random dots tends to form confgurations (constellations).[13] All these innate abilities

365 demonstrate how the eye and the mind are seeking pattern and simple whole shapes. When we look at more complex visual images such as paintings we can see that art has been a continuous attempt to "notate" visual information.

Visual thinking Main article: Visual thinking Tought processes are diffused and interconnected and are cognitive at a sensory level. Te mind thinks at its deepest level in sense material, and the two hemispheres of the brain deal with different kinds of thought.[14] Te brain is divided into two hemispheres and a thick bundle of nerve fbres enable these two halves to communicate with each other.[15][16] In most people the ability to organize and produce speech is predominantly located in the left side. Appreciating spatial perceptions depends more on the right hemisphere, although there is a left hemisphere contribution.[17] In an attempt to understand how designers solve problems, L. Bruce Archer proposed "that the way designers (and everybody else, for that matter) form images in their mind's eye, manipulating and evaluating ideas before, during and after externalising them, constitutes a cognitive system comparable with but different from, the verbal language system. Indeed we believe that human beings have an innate capacity for cognitive modelling, and its expression through sketching, drawing, construction, acting out and so on, that is fundamental to human thought."[18]

Art in education Te visual language begins to develop in babies as the eye and brain become able to focus, and be able to recognize patterns. Children's drawings show a process of increasing perceptual awareness and range of elements to express personal experience and ideas.[19] Te development of the visual aspect of language communication in education has been referred to as graphicacy,[20] as a parallel discipline to literacy and numeracy. Te ability to think and communicate in visual terms is part of, and of equal importance in the learning process, with that of literacy and numeracy. Te visual artist, as Michael Twyman[21] has pointed out, has developed the ability to handle the visual language to communicate ideas. Tis includes both the understanding and conception and the production of concepts in a visual form.

Art

Art is a diverse range of human activities in creating visual, auditory or performing artifacts (artworks), expressing the author's imaginative or technical skill, intended to be appreciated for their beauty or emotional power. In their most general form these activities include the production of works of art, the criticism of art, the study of the history of art, and the aesthetic dissemination of art.

Te oldest documented forms of art are visual arts, which include creation of images or objects in felds including today painting, sculpture, printmaking, photography, and other visual media. Tese may have been refections of animism and its culture.

Architecture is often included as one of the visual arts; however, like the decorative arts, or advertising, it involves the creation of objects where the practical considerations of use are essential—in a way that they usually are not in a painting, for example.

In modern usage after the 17th century, where aesthetic considerations are paramount, the fne arts are separated and distinguished from acquired skills in general, such as the decorative or applied arts.

Art may be characterized in terms of mimesis (its representation of reality), narrative (storytelling), expression, communication of emotion, or other qualities. During the Romantic period, art came to be seen as "a special faculty of the human mind to be classifed with religion and science".

Tough the defnition of what constitutes art is disputed and has changed over time, general descriptions mention an idea of imaginative or technical skill stemming from human agency and creation.

Te nature of art and related concepts, such as creativity and interpretation, are explored in a branch of philosophy known as aesthetics

366 In the perspective of the history of art, artistic works have existed for almost as long as humankind: from early pre-historic art to contemporary art; however, some theories restrict the concept of "artistic works" to modern Western societies. One early sense of the defnition of art is closely related to the older Latin meaning, which roughly translates to "skill" or "craft," as associated with words such as "artisan." English words derived from this meaning include artifact, artifcial, artifce, medical arts, and military arts. However, there are many other colloquial uses of the word, all with some relation to its etymology.

20th-century Rwandan bottle. Artistic works may serve practical functions, in addition to their decorative value. Few modern scholars have been more divided than Plato and Aristotle on the question concerning the importance of art, with Aristotle strongly supporting art in general and Plato generally being opposed to its relative importance.

Several dialogues in Plato tackle questions about art: Socrates says that poetry is inspired by the muses, and is not rational. He speaks approvingly of this, and other forms of divine madness (drunkenness, eroticism, and dreaming) in the Phaedrus (265a–c), and yet in the Republic wants to outlaw Homer's great poetic art, and laughter as well. In Ion, Socrates gives no hint of the disapproval of Homer that he expresses in the Republic. Te dialogue Ion suggests that Homer's Iliad functioned in the ancient Greek world as the Bible does today in the modern Christian world: as divinely inspired literary art that can provide moral guidance, if only it can be properly interpreted.

With regards to the literary art and the musical arts, Aristotle considered epic poetry, tragedy, comedy, dithyrambic poetry and music to be mimetic or imitative art, each varying in imitation by medium, object, and manner. For example, music imitates with the media of rhythm and harmony, whereas dance imitates with rhythm alone, and poetry with language. Te forms also diﬀer in their object of imitation. Comedy, for instance, is a dramatic imitation of men worse than average; whereas tragedy imitates men slightly better than average. Lastly, the forms diﬀer in their manner of imitation—through narrative or character, through change or no change, and through drama or no drama. Aristotle believed that imitation is natural to mankind and constitutes one of mankind's advantages over animals.

Te second, and more recent, sense of the word art as an abbreviation for creative art or fne art emerged in the early 17th century. Fine art refers to a skill used to express the artist's creativity, or to engage the audience's aesthetic sensibilities, or to draw the audience towards consideration of more refned or fner work of art.

Within this latter sense, the word art may refer to several things: (i) a study of a creative skill, (ii) a process of using the creative skill, (iii) a product of the creative skill, or (iv) the audience's experience with the creative skill. Te creative arts (art as discipline) are a collection of disciplines which produce artworks (art as objects) that are compelled by a personal drive (art as activity) and convey a message, mood, or symbolism for the perceiver to interpret (art as experience). Art is something that stimulates an individual's thoughts, emotions, beliefs, or ideas through the senses. Works of art can be explicitly made for this purpose or interpreted on the basis of images or objects. For some scholars, such as Kant, the sciences and the arts could be distinguished by taking science as representing the domain of knowledge and the arts as representing the domain of the freedom of artistic expression.

Often, if the skill is being used in a common or practical way, people will consider it a craft instead of art. Likewise, if the skill is being used in a commercial or industrial way, it may be considered commercial art instead of fne art. On the other hand, crafts and design are sometimes considered applied art. Some art followers have argued that the diﬀerence between fne art and applied art has more to do with value judgments made about the art than any clear defnitional diﬀerence. However, even fne art often has goals beyond pure creativity and self-expression. Te purpose of works of art may be to communicate ideas, such as in politically, spiritually, or philosophically motivated art; to create a sense of beauty (see aesthetics); to explore the nature of perception; for pleasure; or to generate strong emotions. Te purpose may also be seemingly nonexistent.

Te nature of art has been described by philosopher Richard Wollheim as "one of the most elusive of the traditional problems of human culture". Art has been defned as a vehicle for the expression or communication of emotions and ideas, a means for exploring and appreciating formal elements for their own sake, and as mimesis or representation. Art as mimesis has deep roots in the philosophy of Aristotle. Leo Tolstoy identifed art as a use of indirect means to communicate from one person to another. Benedetto Croce and R.G. Collingwood advanced the idealist view that art expresses emotions, and that the work of art therefore essentially exists in the mind of the creator. Te theory of art as form has its roots in the philosophy of Immanuel Kant, and was developed in the early twentieth century by Roger Fry and Clive Bell. More recently, thinkers infuenced by Martin Heidegger have interpreted art as the means by which a community develops for itself a medium for self-expression and interpretation. George Dickie has oﬀered an institutional theory of art that defnes a work of art as any artifact upon which a qualifed person or persons acting on behalf of the social institution commonly referred to as "the art world" has conferred "the status of candidate for appreciation". Larry Shiner has described fne art as "not an essence or a

367 fate but something we have made. Art as we have generally understood it is a European invention barely two hundred years old."

Sculptures, cave paintings, rock paintings and petroglyphs from the Upper Paleolithic dating to roughly 40,000 years ago have been found, but the precise meaning of such art is often disputed because so little is known about the cultures that produced them. Te oldest art objects in the world—a series of tiny, drilled snail shells about 75,000 years old—were discovered in a South African cave. Containers that may have been used to hold paints have been found dating as far back as 100,000 years. Etched shells by Homo erectus from 430,000 and 540,000 years ago were discovered in 2014.

Cave painting of a horse from the Lascaux caves, circa 16,000 BP Many great traditions in art have a foundation in the art of one of the great ancient civilizations: Ancient Egypt, Mesopotamia, Persia, India, China, Ancient Greece, Rome, as well as Inca, Maya, and Olmec. Each of these centers of early civilization developed a unique and characteristic style in its art. Because of the size and duration of these civilizations, more of their art works have survived and more of their infuence has been transmitted to other cultures and later times. Some also have provided the frst records of how artists worked. For example, this period of Greek art saw a veneration of the human physical form and the development of equivalent skills to show musculature, poise, beauty, and anatomically correct proportions.

In Byzantine and Medieval art of the Western Middle Ages, much art focused on the expression of subjects about Biblical and religious culture, and used styles that showed the higher glory of a heavenly world, such as the use of gold in the background of paintings, or glass in mosaics or windows, which also presented fgures in idealized, patterned (fat) forms. Nevertheless, a classical realist tradition persisted in small Byzantine works, and realism steadily grew in the art of Catholic Europe.

Renaissance art had a greatly increased emphasis on the realistic depiction of the material world, and the place of humans in it, refected in the corporeality of the human body, and development of a systematic method of graphical perspective to depict recession in a three-dimensional picture space.

Te stylized signature of Sultan Mahmud II of the Ottoman Empire was written in Islamic calligraphy. It reads Mahmud Khan son of Abdulhamid is forever victorious.

Te Great Mosque of Kairouan in Tunisia, also called the Mosque of Uqba, is one of the fnest, most signifcant and best preserved artistic and architectural examples of early great mosques. Dated in its present state from the 9th century, it is the ancestor and model of all the mosques in the western Islamic lands. In the east, Islamic art's rejection of iconography led to emphasis on geometric patterns, calligraphy, and architecture. Further east, religion dominated artistic styles and forms too. India and Tibet saw emphasis on painted sculptures and dance, while religious painting borrowed many conventions from sculpture and tended to bright contrasting colors with emphasis on outlines. China saw the fourishing of many art forms: jade carving, bronzework, pottery (including the stunning terracotta army of Emperor Qin), poetry, calligraphy, music, painting, drama, fction, etc. Chinese styles vary greatly from era to era and each one is traditionally named after the ruling dynasty. So, for example, Tang dynasty paintings are monochromatic and sparse, emphasizing idealized landscapes, but Ming dynasty paintings are busy and colorful, and focus on telling stories via setting and composition. Japan names its styles after imperial dynasties too, and also saw much interplay between the styles of calligraphy and painting. Woodblock printing became important in Japan after the 17th century.

Te western Age of Enlightenment in the 18th century saw artistic depictions of physical and rational certainties of the clockwork universe, as well as politically revolutionary visions of a post-monarchist world, such as Blake's portrayal of Newton as a divine geometer, or David's propagandistic paintings. Tis led to Romantic rejections of this in favor of pictures of the emotional side and individuality of humans, exemplifed in the novels of Goethe. Te late 19th century then saw a host of artistic movements, such as academic art, Symbolism, impressionism and fauvism among others.

Te history of twentieth-century art is a narrative of endless possibilities and the search for new standards, each being torn down in succession by the next. Tus the parameters of impressionism, Expressionism, Fauvism, Cubism, Dadaism, Surrealism, etc. cannot be maintained very much beyond the time of their invention. Increasing global interaction during this time saw an equivalent infuence of other cultures into Western art. Tus, Japanese woodblock prints (themselves infuenced by Western Renaissance draftsmanship) had an immense infuence on impressionism and subsequent development. Later, African sculptures were taken up by Picasso and to some extent by Matisse. Similarly, in the 19th and 20th centuries the West has had huge impacts on Eastern art with originally western ideas like Communism and Post- Modernism exerting a powerful infuence.

368 Modernism, the idealistic search for truth, gave way in the latter half of the 20th century to a realization of its unattainability. Teodor W. Adorno said in 1970, "It is now taken for granted that nothing which concerns art can be taken for granted any more: neither art itself, nor art in relationship to the whole, nor even the right of art to exist."[30] Relativism was accepted as an unavoidable truth, which led to the period of contemporary art and postmodern criticism, where cultures of the world and of history are seen as changing forms, which can be appreciated and drawn from only with skepticism and irony. Furthermore, the separation of cultures is increasingly blurred and some argue it is now more appropriate to think in terms of a global culture, rather than of regional ones.

Te creative arts are often divided into more specifc categories, typically along perceptually distinguishable categories such as media, genre, styles, and form. Art form refers to the elements of art that are independent of its interpretation or signifcance. It covers the methods adopted by the artist and the physical composition of the artwork, primarily non- semantic aspects of the work (i.e., fgurae), such as color, contour, dimension, medium, melody, space, texture, and value. Form may also include visual design principles, such as arrangement, balance, contrast, emphasis, harmony, proportion, proximity, and rhythm.

In general there are three schools of philosophy regarding art, focusing respectively on form, content, and context. Extreme Formalism is the view that all aesthetic properties of art are formal (that is, part of the art form). Philosophers almost universally reject this view and hold that the properties and aesthetics of art extend beyond materials, techniques, and form. Unfortunately, there is little consensus on terminology for these informal properties. Some authors refer to subject matter and content – i.e., denotations and connotations – while others prefer terms like meaning and signifcance.

Extreme Intentionalism holds that authorial intent plays a decisive role in the meaning of a work of art, conveying the content or essential main idea, while all other interpretations can be discarded.[35] It defnes the subject as the persons or idea represented, and the content as the artist's experience of that subject. For example, the composition of Napoleon I on his Imperial Trone is partly borrowed from the Statue of Zeus at Olympia. As evidenced by the title, the subject is Napoleon, and the content is Ingres's representation of Napoleon as "Emperor-God beyond time and space”. Similarly to extreme formalism, philosophers typically reject extreme intentionalism, because art may have multiple ambiguous meanings and authorial intent may be unknowable and thus irrelevant. Its restrictive interpretation is "socially unhealthy, philosophically unreal, and politically unwise".

Finally, the developing theory of post-structuralism studies art's signifcance in a cultural context, such as the ideas, emotions, and reactions prompted by a work. Te cultural context often reduces to the artist's techniques and intentions, in which case analysis proceeds along lines similar to formalism and intentionalism. However, in other cases historical and material conditions may predominate, such as religious and philosophical convictions, sociopolitical and economic structures, or even climate and geography. Art criticism continues to grow and develop alongside art.

Art can connote a sense of trained ability or mastery of a medium. Art can also simply refer to the developed and eﬃcient use of a language to convey meaning with immediacy and or depth. Art can be defned as an act of expressing feelings, thoughts, and observations.

Tere is an understanding that is reached with the material as a result of handling it, which facilitates one's thought processes. A common view is that the epithet "art", particular in its elevated sense, requires a certain level of creative expertise by the artist, whether this be a demonstration of technical ability, an originality in stylistic approach, or a combination of these two. Traditionally skill of execution was viewed as a quality inseparable from art and thus necessary for its success; for Leonardo da Vinci, art, neither more nor less than his other endeavors, was a manifestation of skill. Rembrandt's work, now praised for its ephemeral virtues, was most admired by his contemporaries for its virtuosity. At the turn of the 20th century, the adroit performances of John Singer Sargent were alternately admired and viewed with skepticism for their manual fuency, yet at nearly the same time the artist who would become the era's most recognized and peripatetic iconoclast, Pablo Picasso, was completing a traditional academic training at which he excelled.

A common contemporary criticism of some modern art occurs along the lines of objecting to the apparent lack of skill or ability required in the production of the artistic object. In conceptual art, Marcel Duchamp's "Fountain" is among the frst examples of pieces wherein the artist used found objects ("ready-made") and exercised no traditionally recognised set of skills. Tracey Emin's My Bed, or Damien Hirst's Te Physical Impossibility of Death in the Mind of Someone Living follow this example and also manipulate the mass media. Emin slept (and engaged in other activities) in her bed before placing the result in a gallery as work of art. Hirst came up with the conceptual design for the artwork but has left most of the eventual creation of many works to employed artisans. Hirst's celebrity is founded entirely on his ability to produce shocking concepts. Te actual production in many conceptual and contemporary works of art is a matter of assembly of found

369 objects. However, there are many modernist and contemporary artists who continue to excel in the skills of drawing and painting and in creating hands-on works of art.

Art has had a great number of different functions throughout its history, making its purpose difficult to abstract or quantify to any single concept. Tis does not imply that the purpose of Art is "vague", but that it has had many unique, different reasons for being created. Some of these functions of Art are provided in the following outline. Te different purposes of art may be grouped according to those that are non-motivated, and those that are motivated (Lévi-Strauss).

Te non-motivated purposes of art are those that are integral to being human, transcend the individual, or do not fulfll a specifc external purpose. In this sense, Art, as creativity, is something humans must do by their very nature (i.e., no other species creates art), and is therefore beyond utility.

Basic human instinct for harmony, balance, rhythm. Art at this level is not an action or an object, but an internal appreciation of balance and harmony (beauty), and therefore an aspect of being human beyond utility. "Imitation, then, is one instinct of our nature. Next, there is the instinct for 'harmony' and rhythm, meters being manifestly sections of rhythm. Persons, therefore, starting with this natural gift developed by degrees their special aptitudes, till their rude improvisations gave birth to Poetry." -Aristotle

Experience of the mysterious. Art provides a way to experience one's self in relation to the universe. Tis experience may often come unmotivated, as one appreciates art, music or poetry. "Te most beautiful thing we can experience is the mysterious. It is the source of all true art and science." – Albert Einstein

Expression of the imagination. Art provides a means to express the imagination in non-grammatic ways that are not tied to the formality of spoken or written language. Unlike words, which come in sequences and each of which have a defnite meaning, art provides a range of forms, symbols and ideas with meanings that are malleable. "Jupiter's eagle [as an example of art] is not, like logical (aesthetic) attributes of an object, the concept of the sublimity and majesty of creation, but rather something else—something that gives the imagination an incentive to spread its fight over a whole host of kindred representations that provoke more thought than admits of expression in a concept determined by words. Tey furnish an aesthetic idea, which serves the above rational idea as a substitute for logical presentation, but with the proper function, however, of animating the mind by opening out for it a prospect into a feld of kindred representations stretching beyond its ken." -Immanuel Kant

Ritualistic and symbolic functions. In many cultures, art is used in rituals, performances and dances as a decoration or symbol. While these often have no specifc utilitarian (motivated) purpose, anthropologists know that they often serve a purpose at the level of meaning within a particular culture. Tis meaning is not furnished by any one individual, but is often the result of many generations of change, and of a cosmological relationship within the culture. "Most scholars who deal with rock paintings or objects recovered from prehistoric contexts that cannot be explained in utilitarian terms and are thus categorized as decorative, ritual or symbolic, are aware of the trap posed by the term 'art'." -Silva Tomaskova

Motivated purposes of art refer to intentional, conscious actions on the part of the artists or creator. Tese may be to bring about political change, to comment on an aspect of society, to convey a specifc emotion or mood, to address personal psychology, to illustrate another discipline, to (with commercial arts) sell a product, or simply as a form of communication.

Communication. Art, at its simplest, is a form of communication. As most forms of communication have an intent or goal directed toward another individual, this is a motivated purpose. Illustrative arts, such as scientifc illustration, are a form of art as communication. Maps are another example. However, the content need not be scientifc. Emotions, moods and feelings are also communicated through art. "[Art is a set of] artefacts or images with symbolic meanings as a means of communication." – Steve Mithen

Art as entertainment. Art may seek to bring about a particular emotion or mood, for the purpose of relaxing or entertaining the viewer. Tis is often the function of the art industries of Motion Pictures and Video Games. Te Avante-Garde. Art for political change. One of the defning functions of early twentieth-century art has been to use visual images to bring about political change. Art movements that had this goal—Dadaism, Surrealism, Russian constructivism, and Abstract Expressionism, among others—are collectively referred to as the avante-garde arts. "By contrast, the realistic attitude, inspired by positivism, from Saint Tomas Aquinas to Anatole France, clearly seems to me to be hostile to any intellectual or moral advancement. I loathe it, for it is made up of mediocrity, hate, and dull conceit. It is this attitude which today gives birth to these ridiculous books, these insulting plays. It constantly feeds on and derives strength from the newspapers and stultifes both science and art by assiduously fattering the lowest of tastes; clarity bordering on stupidity, a dog's life." – André Breton (Surrealism)

370 Art as a "free zone", removed from the action of the social censure. Unlike the avant-garde movements, which wanted to erase cultural diﬀerences in order to produce new universal values, contemporary art has enhanced its tolerance towards cultural diﬀerences as well as its critical and liberating functions (social inquiry, activism, subversion, deconstruction ...), becoming a more open place for research and experimentation. Art for social inquiry, subversion and/or anarchy. While similar to art for political change, subversive or deconstructivist art may seek to question aspects of society without any specifc political goal. In this case, the function of art may be simply to criticize some aspect of society.

Graffiti art and other types of street art are graphics and images that are spray-painted or stencilled on publicly viewable walls, buildings, buses, trains, and bridges, usually without permission. Certain art forms, such as graffiti, may also be illegal when they break laws (in this case vandalism). Art for social causes. Art can be used to raise awareness for a large variety of causes. A number of art activities were aimed at raising awareness of autism, cancer, human trafficking, and a variety of other topics, such as ocean conservation, human rights in Darfur, murdered and missing Aboriginal women, elder abuse, and pollution. Trashion, using trash to make fashion, practiced by artists such as Marina DeBris is one example of using art to raise awareness about pollution.

Art for psychological and healing purposes. Art is also used by art therapists, psychotherapists and clinical psychologists as art therapy. Te Diagnostic Drawing Series, for example, is used to determine the personality and emotional functioning of a patient. Te end product is not the principal goal in this case, but rather a process of healing, through creative acts, is sought. Te resultant piece of artwork may also oﬀer insight into the troubles experienced by the subject and may suggest suitable approaches to be used in more conventional forms of psychiatric therapy.

Art for propaganda, or commercialism. Art is often utilized as a form of propaganda, and thus can be used to subtly infuence popular conceptions or mood. In a similar way, art that tries to sell a product also infuences mood and emotion. In both cases, the purpose of art here is to subtly manipulate the viewer into a particular emotional or psychological response toward a particular idea or object.

Art as a ftness indicator. It has been argued that the ability of the human brain by far exceeds what was needed for survival in the ancestral environment. One evolutionary psychology explanation for this is that the human brain and associated traits (such as artistic ability and creativity) are the human equivalent of the peacock's tail. Te purpose of the male peacock's extravagant tail has been argued to be to attract females (see also Fisherian runaway and handicap principle). According to this theory superior execution of art was evolutionary important because it attracted mates.

Te functions of art described above are not mutually exclusive, as many of them may overlap. For example, art for the purpose of entertainment may also seek to sell a product, i.e. the movie or video game.

Art has long been controversial, that is to say disliked by some viewers, for a wide variety of reasons, though most pre- modern controversies are dimly recorded, or completely lost to a modern view. Iconoclasm is the destruction of art that is disliked for a variety of reasons, including religious ones. Aniconism is a general dislike of either all fgurative images, or often just religious ones, and has been a thread in many major religions. It has been a crucial factor in the history of Islamic art, where depictions of Muhammad remain especially controversial. Much art has been disliked purely because it depicted or otherwise stood for unpopular rulers, parties or other groups. Artistic conventions have often been conservative and taken very seriously by art critics, though often much less so by a wider public. Te iconographic content of art could cause controversy, as with late medieval depictions of the new motif of the Swoon of the Virgin in scenes of the Crucifxion of Jesus. Te Last Judgment by Michelangelo was controversial for various reasons, including breaches of decorum through nudity and the Apollo-like pose of Christ.

Te content of much formal art through history was dictated by the patron or commissioner rather than just the artist, but with the advent of Romanticism, and economic changes in the production of art, the artists' vision became the usual determinant of the content of his art, increasing the incidence of controversies, though often reducing their signifcance. Strong incentives for perceived originality and publicity also encouraged artists to court controversy. Téodore Géricault's Raft of the Medusa (c. 1820), was in part a political commentary on a recent event. Édouard Manet's Le Déjeuner sur l'Herbe (1863), was considered scandalous not because of the nude woman, but because she is seated next to men fully dressed in the clothing of the time, rather than in robes of the antique world. John Singer Sargent's Madame Pierre Gautreau (Madam X) (1884), caused a controversy over the reddish pink used to color the woman's ear lobe, considered far too suggestive and supposedly ruining the high-society model's reputation.

Te gradual abandonment of naturalism and the depiction of realistic representations of the visual appearance of subjects in the 19th and 20th centuries led to a rolling controversy lasting for over a century. In the twentieth century, Pablo Picasso's Guernica (1937) used arresting cubist techniques and stark monochromatic oils, to depict the harrowing consequences of a contemporary bombing of a small, ancient Basque town. Leon Golub's Interrogation III (1981), depicts a female 371 nude, hooded detainee strapped to a chair, her legs open to reveal her sexual organs, surrounded by two tormentors dressed in everyday clothing. Andres Serrano's Piss Christ (1989) is a photograph of a crucifx, sacred to the Christian religion and representing Christ's sacrifce and fnal suﬀering, submerged in a glass of the artist's own urine. Te resulting uproar led to comments in the United States Senate about public funding of the arts.

Before Modernism, aesthetics in Western art was greatly concerned with achieving the appropriate balance between diﬀerent aspects of realism or truth to nature and the ideal; ideas as to what the appropriate balance is have shifted to and fro over the centuries. Tis concern is largely absent in other traditions of art. Te aesthetic theorist John Ruskin, who championed what he saw as the naturalism of J. M. W. Turner, saw art's role as the communication by artifce of an essential truth that could only be found in nature.

Te defnition and evaluation of art has become especially problematic since the 20th century. Richard Wollheim distinguishes three approaches to assessing the aesthetic value of art: the Realist, whereby aesthetic quality is an absolute value independent of any human view; the Objectivist, whereby it is also an absolute value, but is dependent on general human experience; and the Relativist position, whereby it is not an absolute value, but depends on, and varies with, the human experience of diﬀerent humans.

Arrival of Modernism

Composition II in Red, Blue, and Yellow (1930) by Piet Mondrian (Dutch, 1872–1944) Te arrival of Modernism in the late nineteenth century lead to a radical break in the conception of the function of art, and then again in the late twentieth century with the advent of postmodernism. Clement Greenberg's 1960 article "Modernist Painting" defnes modern art as "the use of characteristic methods of a discipline to criticize the discipline itself". Greenberg originally applied this idea to the Abstract Expressionist movement and used it as a way to understand and justify fat (non- illusionistic) abstract painting:

Realistic, naturalistic art had dissembled the medium, using art to conceal art; modernism used art to call attention to art. Te limitations that constitute the medium of painting—the fat surface, the shape of the support, the properties of the pigment—were treated by the Old Masters as negative factors that could be acknowledged only implicitly or indirectly. Under Modernism these same limitations came to be regarded as positive factors, and were acknowledged openly.

After Greenberg, several important art theorists emerged, such as Michael Fried, T. J. Clark, Rosalind Krauss, Linda Nochlin and Griselda Pollock among others. Tough only originally intended as a way of understanding a specifc set of artists, Greenberg's defnition of modern art is important to many of the ideas of art within the various art movements of the 20th century and early 21st century.

Pop artists like Andy Warhol became both noteworthy and infuential through work including and possibly critiquing popular culture, as well as the art world. Artists of the 1980s, 1990s, and 2000s expanded this technique of self-criticism beyond high art to all cultural image-making, including fashion images, comics, billboards and pornography.

Duchamp once proposed that art is any activity of any kind- everything. However, the way that only certain activities are classifed today as art is a social construction. Tere is evidence that there may be an element of truth to this. Te Invention of Art: A Cultural History is an art history book which examines the construction of the modern system of the arts i.e. Fine Art. Shiner fnds evidence that the older system of the arts before our modern system (fne art) held art to be any skilled human activity i.e. Ancient Greek society did not possess the term art but techne. Techne can be understood neither as art or craft, the reason being that the distinctions of art and craft are historical products that came later on in human history. Techne included painting, sculpting and music but also; cooking, medicine, horsemanship, geometry, carpentry, prophecy, and farming etc.

Following Duchamp during the frst half of the twentieth century, a signifcant shift to general aesthetic theory took place which attempted to apply aesthetic theory between various forms of art, including the literary arts and the visual arts, to each other. Tis resulted in the rise of the New Criticism school and debate concerning the intentional fallacy. At issue was the question of whether the aesthetic intentions of the artist in creating the work of art, whatever its specifc form, should be associated with the criticism and evaluation of the fnal product of the work of art, or, if the work of art should be evaluated on its own merits independent of the intentions of the artist.

In 1946, William K. Wimsatt and Monroe Beardsley published a classic and controversial New Critical essay entitled "Te Intentional Fallacy", in which they argued strongly against the relevance of an author's intention, or "intended meaning" in the analysis of a literary work. For Wimsatt and Beardsley, the words on the page were all that mattered; importation of meanings from outside the text was considered irrelevant, and potentially distracting.

372 In another essay, "Te Aﬀective Fallacy," which served as a kind of sister essay to "Te Intentional Fallacy" Wimsatt and Beardsley also discounted the reader's personal/emotional reaction to a literary work as a valid means of analyzing a text. Tis fallacy would later be repudiated by theorists from the reader-response school of literary theory. Ironically, one of the leading theorists from this school, Stanley Fish, was himself trained by New Critics. Fish criticizes Wimsatt and Beardsley in his essay "Literature in the Reader" (1970).

As summarized by Gaut and Livingston in their essay "Te Creation of Art": "Structuralist and post-structuralists theorists and critics were sharply critical of many aspects of New Criticism, beginning with the emphasis on aesthetic appreciation and the so-called autonomy of art, but they reiterated the attack on biographical criticisms's assumption that the artist's activities and experience were a privileged critical topic.” Tese authors contend that: "Anti-intentionalists, such as formalists, hold that the intentions involved in the making of art are irrelevant or peripheral to correctly interpreting art. So details of the act of creating a work, though possibly of interest in themselves, have no bearing on the correct interpretation of the work."

Gaut and Livingston defne the intentionalists as distinct from formalists stating that: "Intentionalists, unlike formalists, hold that reference to intentions is essential in fxing the correct interpretation of works." Tey quote Richard Wollheim as stating that, "Te task of criticism is the reconstruction of the creative process, where the creative process must in turn be thought of as something not stopping short of, but terminating on, the work of art itself."

Te end of the 20th century fostered an extensive debate known as the linguistic turn controversy, or the "innocent eye debate", and generally referred to as the structuralism-poststructuralism debate in the philosophy of art. Tis debate discussed the encounter of the work of art as being determined by the relative extent to which the conceptual encounter with the work of art dominates over the perceptual encounter with the work of art.

Decisive for the linguistic turn debate in art history and the humanities were the works of yet another tradition, namely the structuralism of Ferdinand de Saussure and the ensuing movement of poststructuralism. In 1981, the artist Mark Tansey created a work of art titled "Te Innocent Eye" as a criticism of the prevailing climate of disagreement in the philosophy of art during the closing decades of the 20th century. Infuential theorists include Judith Butler, Luce Irigaray, Julia Kristeva, Michel Foucault and Jacques Derrida. Te power of language, more specifcally of certain rhetorical tropes, in art history and historical discourse was explored by Hayden White. Te fact that language is not a transparent medium of thought had been stressed by a very diﬀerent form of philosophy of language which originated in the works of Johann Georg Hamann and Wilhelm von Humboldt. Ernst Gombrich and Nelson Goodman in his book Languages of Art: An Approach to a Teory of Symbols came to hold that the conceptual encounter with the work of art predominated exclusively over the perceptual and visual encounter with the work of art during the 1960s and 1970s. He was challenged on the basis of research done by the Nobel prize winning psychologist Roger Sperry who maintained that the human visual encounter was not limited to concepts represented in language alone (the linguistic turn) and that other forms of psychological representations of the work of art were equally defensible and demonstrable. Sperry's view eventually prevailed by the end of the 20th century with aesthetic philosophers such as Nick Zangwill strongly defending a return to moderate aesthetic formalism among other alternatives.

Te original Fountain by Marcel Duchamp, 1917, photographed by Alfred Stieglitz at the 291 after the 1917 Society of Independent Artists exhibit. Stieglitz used a backdrop of Te Warriors by Marsden Hartley to photograph the urinal. Te exhibition entry tag can be clearly seen.

Disputes as to whether or not to classify something as a work of art are referred to as classifcatory disputes about art. Classifcatory disputes in the 20th century have included cubist and impressionist paintings, Duchamp's Fountain, the movies, superlative imitations of banknotes, conceptual art, and video games.[79] Philosopher David Novitz has argued that disagreement about the defnition of art are rarely the heart of the problem. Rather, "the passionate concerns and interests that humans vest in their social life" are "so much a part of all classifcatory disputes about art" (Novitz, 1996). According to Novitz, classifcatory disputes are more often disputes about societal values and where society is trying to go than they are about theory proper. For example, when the Daily Mail criticized Hirst's and Emin's work by arguing "For 1,000 years art has been one of our great civilising forces. Today, pickled sheep and soiled beds threaten to make barbarians of us all" they are not advancing a defnition or theory about art, but questioning the value of Hirst's and Emin's work.[80] In 1998, Arthur Danto, suggested a thought experiment showing that "the status of an artifact as work of art results from the ideas a culture applies to it, rather than its inherent physical or perceptible qualities. Cultural interpretation (an art theory of some kind) is therefore constitutive of an object's arthood."

Anti-art is a label for art that intentionally challenges the established parameters and values of art; it is term associated with Dadaism and attributed to Marcel Duchamp just before World War I, when he was making art from found objects. One of

373 these, Fountain (1917), an ordinary urinal, has achieved considerable prominence and infuence on art.[83] Anti-art is a feature of work by Situationist International, the lo-f Mail art movement, and the Young British Artists, though it is a form still rejected by the Stuckists, who describe themselves as anti-anti-art.

Surrealism is a cultural movement that began in the early 1920s, and is best known for its visual artworks and writings. Artists painted unnerving, illogical scenes with photographic precision, created strange creatures from everyday objects, and developed painting techniques that allowed the unconscious to express itself.[1] Its aim was to "resolve the previously contradictory conditions of dream and reality into an absolute reality, a super-reality".[2][3][4]

Works of surrealism feature the element of surprise, unexpected juxtapositions and non sequitur; however, many surrealist artists and writers regard their work as an expression of the philosophical movement frst and foremost, with the works being an artifact. Leader André Breton was explicit in his assertion that Surrealism was, above all, a revolutionary movement.

Surrealism developed out of the Dada activities during World War I and the most important center of the movement was Paris. From the 1920s onward, the movement spread around the globe, eventually aﬀecting the visual arts, literature, flm, and music of many countries and languages, as well as political thought and practice, philosophy, and social theory.

Expressionism is a modernist movement, initially in poetry and painting, originating in Germany at the beginning of the 20th century. Its typical trait is to present the world solely from a subjective perspective, distorting it radically for emotional eﬀect in order to evoke moods or ideas.[1][2] Expressionist artists have sought to express the meaning[3] of emotional experience rather than physical reality.[3][4]

Expressionism developed as an avant-garde style before the First World War. It remained popular during the Weimar Republic,[1] particularly in Berlin. Te style extended to a wide range of the arts, including expressionist architecture, painting, literature, theatre, dance, flm and music.[5]

Te term is sometimes suggestive of angst. In a historical sense, much older painters such as Matthias Grünewald and El Greco are sometimes termed expressionist, though the term is applied mainly to 20th-century works. Te Expressionist emphasis on individual and subjective perspective has been characterized as a reaction to positivism and other artistic styles such as Naturalism and Impressionism.[6]

Impressionism is a 19th-century art movement characterized by relatively small, thin, yet visible brush strokes, open composition, emphasis on accurate depiction of light in its changing qualities (often accentuating the eﬀects of the passage of time), ordinary subject matter, inclusion of movement as a crucial element of human perception and experience, and unusual visual angles. Impressionism originated with a group of Paris-based artists whose independent exhibitions brought them to prominence during the 1870s and 1880s.

Te Impressionists faced harsh opposition from the conventional art community in France. Te name of the style derives from the title of a Claude Monet work, Impression, soleil levant (Impression, Sunrise), which provoked the critic Louis Leroy to coin the term in a satirical review published in the Parisian newspaper Le Charivari.

Te development of Impressionism in the visual arts was soon followed by analogous styles in other media that became known as impressionist music and impressionist literature.

Realism, sometimes called naturalism, in the arts is generally the attempt to represent subject matter truthfully, without artifciality and avoiding artistic conventions, or implausible, exotic, and supernatural elements. Realism has been prevalent in the arts at many periods, and can be in large part a matter of technique and training, and the avoidance of stylization.

In the visual arts, illusionistic realism is the accurate depiction of lifeforms, perspective, and the details of light and colour. But realist or naturalist works of art may, as well or instead of illusionist realism, be "realist" in their subject-matter, and emphasize the mundane, ugly or sordid. Tis is typical of the 19th-century Realist movement that began in France in the 1850s, after the 1848 Revolution,[1] and also social realism, regionalism, or kitchen sink realism. Te Realist painters rejected Romanticism, which had come to dominate French literature and art, with roots in the late 18th century.

Tere have been various movements invoking realism in the other arts, such as the opera style of verismo, literary realism, theatrical realism, and Italian neorealist cinema.

Te development of increasingly accurate representation of the visual appearances of things has a long history in art. It includes elements such as the accurate depiction of the anatomy of humans and animals, of perspective and eﬀects of distance, and of detailed eﬀects of light and colour. Te Art of the Upper Paleolithic in Europe achieved remarkably lifelike

374 depictions of animals, and Ancient Egyptian art developed conventions involving both stylization and idealization that nevertheless allowed very effective depictions to be produced very widely and consistently. Ancient Greek art is commonly recognised as having made great progress in the representation of anatomy, and has remained an infuential model ever since. No original works on panels or walls by the great Greek painters survive, but from literary accounts, and the surviving corpus of derivative works (mostly Graeco-Roman works in mosaic) it is clear that illusionism was highly valued in painting. Pliny the Elder's famous story of birds pecking at grapes painted by Zeuxis in the 5th century BC may well be a legend, but indicates the aspiration of Greek painting. As well as accuracy in shape, light and colour, Roman paintings show an unscientifc but effective knowledge of representing distant objects smaller than closer ones, and representing regular geometric forms such as the roof and walls of a room with perspective. Tis progress in illusionistic effects in no way meant a rejection of idealism; statues of Greek gods and heroes attempt to represent with accuracy idealized and beautiful forms, though other works, such as heads of the famously ugly Socrates, were allowed to fall below these ideal standards of beauty. Roman portraiture, when not under too much Greek infuence, shows a greater commitment to a truthful depiction of its subjects.

Bas-de-page of the Baptism of Christ, "Hand G" (Jan van Eyck?), Turin-Milan Hours. An advanced illusionistic work for c. 1425, with the dove of the Holy Ghost in the sky. Te art of Late Antiquity famously rejected illusionism for expressive force, a change already well underway by the time Christianity began to aﬀect the art of the elite. In the West classical standards of illusionism did not begin to be reached again until the Late medieval and Early Renaissance periods, and were helped, frst in the Netherlands in the early 15th century, and around the 1470s in Italy, by the development of new techniques of oil painting which allowed very subtle and precise eﬀects of light to be painted using very small brushes and several layers of paint and glaze. Scientifc methods of representing perspective were developed in Italy in the early 15th century and gradually spread across Europe, and accuracy in anatomy rediscovered under the infuence of classical art. As in classical times, idealism remained the norm.

Te accurate depiction of landscape in painting had also been developing in Early Netherlandish/Early Northern Renaissance and Italian Renaissance painting, and was then brought to a very high level in 17th-century Dutch Golden Age painting, with very subtle techniques for depicting a range of weather conditions and degrees of natural light. After being another development of Early Netherlandish painting, by 1600 European portraiture could give a very good likeness in both painting and sculpture, though the subjects were often idealized by smoothing features or giving them an artifcial pose. Still life paintings, and still life elements in other works, played a considerable role in developing illusionistic painting, though in the Netherlandish tradition of fower painting they long lacked "realism", in that fowers from all seasons were typically used, either from the habit of assembling compositions from individual drawings, or as a deliberate convention; the large displays of bouquets in vases, though close to modern displays of cut fowers that they have infuenced, were entirely atypical of 17th- century habits, where fowers were displayed one at a time. Intriguingly, having led the development of illusionic painting, still life was to be equally signifcant in its abandonment in Cubism.

Realism or naturalism as the depiction of ordinary, everyday subjects

Woodcutting, miniature from a set of Labours of the Months by Simon Bening, c. 1550 Te depiction of ordinary, everyday subjects in art also has a long history, though it was often squeezed into the edges of compositions, or shown at a smaller scale. Tis was partly because art was expensive, and usually commissioned for specifc religious, political or personal reasons, that allowed only a relatively small amount of space or eﬀort to be devoted to such scenes. Drolleries in the margins of medieval illuminated manuscripts sometimes contain small scenes of everyday life, and the development of perspective created large background areas in many scenes set outdoors that could be made more interesting by including small fgures going about their everyday lives. Medieval and Early Renaissance art by convention usually showed non-sacred fgures in contemporary dress, so no adjustment was needed for this even in religious or historical scenes set in ancient times.

Early Netherlandish painting brought the painting of portraits as low down the social scale as the prosperous merchants of Flanders, and in some of these, notably the Arnolfni Portrait by Jan van Eyck (1434), and more often in religious scenes such as the Merode Altarpiece, by Robert Campin and his workshop (circa 1427), include very detailed depictions of middle-class interiors full of lovingly depicted objects. However these objects are at least largely there because they carry layers of complex signifcance and symbolism that undercut any commitment to realism for its own sake. Cycles of the Labours of the Months in late medieval art, of which many examples survive from books of hours, concentrate on peasants labouring on diﬀerent tasks through the seasons, often in a rich landscape background, and were signifcant both in developing landscape art and the depiction of everyday working-class people.

Annibale Carracci, Te Butcher's Shop, early 1580s In the 16th century there was a fashion for the depiction in large paintings of scenes of people working, especially in food markets and kitchens: in many the food is given as much prominence as the workers. Artists included Pieter Aertsen and his

375 nephew Joachim Beuckelaer in the Netherlands, working in an essentially Mannerist style, and in Italy the young Annibale Carracci in the 1580s, using a very down to earth unpolished style, with Bartolomeo Passerotti somewhere between the two. Pieter Bruegel the Elder pioneered large panoramic scenes of peasant life. Such scenes acted as a prelude for the popularity of scenes of work in genre painting in the 17th century, which appeared all over Europe, with Dutch Golden Age painting sprouting several diﬀerent subgenres of such scenes, the Bamboccianti (though mostly from the Low Countries) in Italy, and in Spain the genre of bodegones, and the introduction of unidealized peasants into history paintings by Jusepe de Ribera and Velázquez. Te Le Nain brothers in France and many Flemish artists including Adriaen Brouwer and David Teniers the Elder and Younger painted peasants, but rarely townsfolk. In the 18th century small paintings of working people working remained popular, mostly drawing on the Dutch tradition, and especially featuring women.

Much art depicting ordinary people, especially in the form of prints, was comic and moralistic, but the mere poverty of the subjects seems relatively rarely have been part of the moral message. From the mid-19th century onwards this changed, and the diﬃculties of life for the poor were emphasized. Despite this trend coinciding with large-scale migration from the countryside to cities in most of Europe, painters still tended to paint poor rural people, largely leaving illustrators such as Gustave Doré to show the horrors of city slums. Crowded city street scenes were popular with the Impressionists and related painters, especially ones showing Paris.

Medieval manuscript illuminators were often asked to illustrate technology, but after the Renaissance such images continued in book illustration and prints, but with the exception of marine painting largely disappeared in fne art until the early Industrial Revolution, scenes from which were painted by a few painters such as Joseph Wright of Derby and Philip James de Loutherbourg. Such subjects probably failed to sell very well, and there is a noticeable absence of industry, other than a few railway scenes, in painting until the later 19th century, when works began to be commissioned, typically by industrialists or for institutions in industrial cities, often on a large scale, and sometimes given a quasi-heroic treatment.

American realism, a movement of the early 20th century, is one of many modern movements to use realism in this sense.

In metaphysics, realism about a given object is the view that this object exists in reality independently of our conceptual scheme. In philosophical terms, these objects are ontologically independent of someone's conceptual scheme, perceptions, linguistic practices, beliefs, etc.

Realism can be applied to many philosophically interesting objects and phenomena: other minds, the past or the future, universals, mathematical entities (such as natural numbers), moral categories, the physical world, and thought.

Realism can also be a view about the nature of reality in general, where it claims that the world exists independent of the mind, as opposed to non-realist views (like some forms of skepticism and solipsism, which question our ability to assert the world is independent of our mind). Philosophers who profess realism often claim that truth consists in a correspondence between cognitive representations and reality.[1]

Realists tend to believe that whatever we believe now is only an approximation of reality but that the accuracy and fullness of understanding can be improved.[2] In some contexts, realism is contrasted with idealism. Today it is more usually contrasted with anti-realism, for example in the philosophy of science.

Te oldest use of the term "realism" appears in medieval scholastic interpretations and adaptations of ancient Greek philosophy.

Abstract: Technically, an important predecessor is surrealism, with its emphasis on spontaneous, automatic, or subconscious creation. Jackson Pollock's dripping paint onto a canvas laid on the foor is a technique that has its roots in the work of André Masson, Max Ernst, and David Alfaro Siqueiros. Te newer research tends to put the exile-surrealist Wolfgang Paalen in the position of the artist and theoretician who fostered the theory of the viewer-dependent possibility space through his paintings and his magazine DYN. Paalen considered ideas of quantum mechanics, as well as idiosyncratic interpretations of the totemic vision and the spatial structure of native-Indian painting from British Columbia and prepared the ground for the new spatial vision of the young American abstracts. His long essay Totem Art (1943) had considerable infuence on such artists as Martha Graham, Isamu Noguchi, Jackson Pollock, Mark Rothko and Barnett Newman. [3] Around 1944 Barnett Newman tried to explain America's newest art movement and included a list of "the men in the new movement." Paalen is mentioned twice; other artists mentioned are Gottlieb, Rothko, Pollock, Hofmann, Baziotes, Gorky and others. Motherwell is mentioned with a question mark.[4] Another important early manifestation of what came to be abstract expressionism is the work of American Northwest artist Mark Tobey, especially his "white writing" canvases, which, though generally not large in scale, anticipate the "all-over" look of Pollock's drip paintings.

376 Te movement's name is derived from the combination of the emotional intensity and self-denial of the German Expressionists with the anti-fgurative aesthetic of the European abstract schools such as Futurism, the Bauhaus, and Synthetic Cubism. Additionally, it has an image of being rebellious, anarchic, highly idiosyncratic and, some feel, nihilistic. [5] In practice, the term is applied to any number of artists working (mostly) in New York who had quite diﬀerent styles, and even to work that is neither especially abstract nor expressionist. California abstract expressionist Jay Meuser, who typically painted in the non-objective style, wrote about his painting Mare Nostrum, "It is far better to capture the glorious spirit of the sea than to paint all of its tiny ripples." Pollock's energetic "action paintings", with their "busy" feel, are diﬀerent, both technically and aesthetically, from the violent and grotesque Women series of Willem de Kooning's fgurative paintings and the rectangles of color in Mark Rothko's Color Field paintings (which are not what would usually be called expressionist, and which Rothko denied were abstract). Yet all four artists are classifed as abstract expressionists.

Abstract expressionism has many stylistic similarities to the Russian artists of the early 20th century such as Wassily Kandinsky. Although it is true that spontaneity or the impression of spontaneity characterized many of the abstract expressionists' works, most of these paintings involved careful planning, especially since their large size demanded it. With artists such as Paul Klee, Wassily Kandinsky, Emma Kunz, and later on Rothko, Barnett Newman, and Agnes Martin, abstract art clearly implied expression of ideas concerning the spiritual, the unconscious, and the mind.[6]

Why this style gained mainstream acceptance in the 1950s is a matter of debate. American social realism had been the mainstream in the 1930s. It had been infuenced not only by the Great Depression, but also by the muralists of Mexico such as David Alfaro Siqueiros and Diego Rivera. Te political climate after World War II did not long tolerate the social protests of these painters. Abstract expressionism arose during World War II and began to be showcased during the early forties at galleries in New York such as Te Art of Tis Century Gallery. Te McCarthy era after World War II was a time of artistic censorship in the United States, but if the subject matter were totally abstract then it would be seen as apolitical, and therefore safe. Or if the art was political, the message was largely for the insiders.[7]

While the movement is closely associated with painting, and painters such as Arshile Gorky, Franz Kline, Clyﬀord Still, Hans Hofmann, Willem de Kooning, Jackson Pollock, and others, collagist Anne Ryan and certain sculptors in particular were also integral to abstract expressionism.[8] David Smith, and his wife Dorothy Dehner, Herbert Ferber, Isamu Noguchi, Ibram Lassaw, Teodore Roszak, Phillip Pavia, Mary Callery, Richard Stankiewicz, Louise Bourgeois, and Louise Nevelson in particular were some of the sculptors considered as being important members of the movement. In addition, the artists David Hare, John Chamberlain, James Rosati, Mark di Suvero, and sculptors Richard Lippold, Raoul Hague, George Rickey, Reuben Nakian, and even Tony Smith, Seymour Lipton, Joseph Cornell, and several others[9] were integral parts of the abstract expressionist movement. Many of the sculptors listed participated in the Ninth Street Show,[9] a famous exhibition curated by Leo Castelli on East Ninth Street in New York City in 1951. Besides the painters and sculptors of the period the New York School of abstract expressionism also generated a number of supportive poets, including Frank O'Hara and photographers such as Aaron Siskind and Fred McDarrah, (whose book Te Artist's World in Pictures documented the New York School during the 1950s), and flmmakers—notably Robert Frank—as well.

Although the abstract expressionist school spread quickly throughout the United States, the major centers of this style were New York City and the San Francisco Bay area of California. Abstract art uses a visual language of shape, form, color and line to create a composition which may exist with a degree of independence from visual references in the world.[1] Western art had been, from the Renaissance up to the middle of the 19th century, underpinned by the logic of perspective and an attempt to reproduce an illusion of visible reality. Te arts of cultures other than the European had become accessible and showed alternative ways of describing visual experience to the artist. By the end of the 19th century many artists felt a need to create a new kind of art which would encompass the fundamental changes taking place in technology, science and philosophy. Te sources from which individual artists drew their theoretical arguments were diverse, and refected the social and intellectual preoccupations in all areas of Western culture at that time. [2]

Abstract art, non-fgurative art, non-objective art, and non-representational art are loosely related terms. Tey are similar, but perhaps not of identical meaning.

Abstraction indicates a departure from reality in depiction of imagery in art. Tis departure from accurate representation can be slight, partial, or complete. Abstraction exists along a continuum. Even art that aims for verisimilitude of the highest degree can be said to be abstract, at least theoretically, since perfect representation is likely to be exceedingly elusive. Artwork which takes liberties, altering for instance color and form in ways that are conspicuous, can be said to be partially abstract. Total abstraction bears no trace of any reference to anything recognizable. In geometric abstraction, for instance, one is

377 unlikely to fnd references to naturalistic entities. Figurative art and total abstraction are almost mutually exclusive. But fgurative and representational (or realistic) art often contains partial abstraction.

Both geometric abstraction and lyrical abstraction are often totally abstract. Among the very numerous art movements that embody partial abstraction would be for instance fauvism in which color is conspicuously and deliberately altered vis-a-vis reality, and cubism, which alters the forms of the real life entities depicted. [3][4]

Somewhat in relation to the above, the word art is also used to apply judgments of value, as in such expressions as "that meal was a work of art" (the cook is an artist), or "the art of deception", (the highly attained level of skill of the deceiver is praised). It is this use of the word as a measure of high quality and high value that gives the term its favor of subjectivity. Making judgments of value requires a basis for criticism. At the simplest level, a way to determine whether the impact of the object on the senses meets the criteria to be considered art is whether it is perceived to be attractive or repulsive. Tough perception is always colored by experience, and is necessarily subjective, it is commonly understood that what is not somehow aesthetically satisfying cannot be art. However, "good" art is not always or even regularly aesthetically appealing to a majority of viewers. In other words, an artist's prime motivation need not be the pursuit of the aesthetic. Also, art often depicts terrible images made for social, moral, or thought-provoking reasons. For example, Francisco Goya's painting depicting the Spanish shootings of 3rd of May 1808 is a graphic depiction of a fring squad executing several pleading civilians. Yet at the same time, the horrifc imagery demonstrates Goya's keen artistic ability in composition and execution and produces ftting social and political outrage. Tus, the debate continues as to what mode of aesthetic satisfaction, if any, is required to defne 'art'.

Te assumption of new values or the rebellion against accepted notions of what is aesthetically superior need not occur concurrently with a complete abandonment of the pursuit of what is aesthetically appealing. Indeed, the reverse is often true, that the revision of what is popularly conceived of as being aesthetically appealing allows for a re-invigoration of aesthetic sensibility, and a new appreciation for the standards of art itself. Countless schools have proposed their own ways to defne quality, yet they all seem to agree in at least one point: once their aesthetic choices are accepted, the value of the work of art is determined by its capacity to transcend the limits of its chosen medium to strike some universal chord by the rarity of the skill of the artist or in its accurate refection in what is termed the zeitgeist. Art is often intended to appeal to and connect with human emotion. It can arouse aesthetic or moral feelings, and can be understood as a way of communicating these feelings. Artists express something so that their audience is aroused to some extent, but they do not have to do so consciously. Art may be considered an exploration of the human condition; that is, what it is to be human.

Graﬃti

Graffiti (both singular and plural; the singular graffito is very rare in English except in archeology)[1][2][3] is writing or drawings made on a wall or other surface, usually without permission and within public view.[2][3] Graffiti ranges from simple written words to elaborate wall paintings, and it has existed since ancient times, with examples dating back to ancient Egypt, ancient Greece, and the Roman Empire.[4]

In modern times, paint (particularly spray paint) and marker pens have become the most commonly used graﬃti materials. In most countries, marking or painting property without the property owner's permission is considered defacement and vandalism, which is a punishable crime.

Unrelated to hip-hop graﬃti, gangs use their own form of graﬃti to mark territory or to serve as an indicator of gang-related activities.[5]

Controversies that surround graffiti continue to create disagreement amongst city officials, law enforcement, and writers who wish to display and appreciate work in public locations. Tere are many different types and styles of graffiti; it is a rapidly developing art form whose value is highly contested and reviled by many authorities while also subject to protection, sometimes within the same jurisdiction.

Both "graffiti" and its occasional singular form "graffito" are from the Italian word graffiato ("scratched"). "Graffiti" is applied in art history to works of art produced by scratching a design into a surface. A related term is "sgraffito",[6] which involves scratching through one layer of pigment to reveal another beneath it. Tis technique was primarily used by potters who would glaze their wares and then scratch a design into it. In ancient times graffiti were carved on walls with a sharp object, although sometimes chalk or coal were used. Te word originates from Greek γράφειν—graphein—meaning "to write”.[7]

378 Te term graﬃti referred to the inscriptions, fgure drawings, and such, found on the walls of ancient sepulchres or ruins, as in the Catacombs of Rome or at Pompeii. Use of the word has evolved to include any graphics applied to surfaces in a manner that constitutes vandalism.[8]

Te only known source of the Safaitic language, a form of proto-Arabic, is from graﬃti: inscriptions scratched on to the surface of rocks and boulders in the predominantly basalt desert of southern Syria, eastern Jordan and northern Saudi Arabia. Safaitic dates from the frst century BC to the fourth century AD.[9] [10]

Te frst known example of "modern style"[clarifcation needed] graﬃti survives in the ancient Greek city of Ephesus (in modern-day Turkey). Local guides say it is an advertisement for prostitution. Located near a mosaic and stone walkway, the graﬃti shows a handprint that vaguely resembles a heart, along with a footprint, a number, and a carved image of a woman's head.

Te ancient Romans carved graffiti on walls and monuments, examples of which also survive in Egypt. Graffiti in the classical world had different connotations than they carry in today's society concerning content. Ancient graffiti displayed phrases of love declarations, political rhetoric, and simple words of thought, compared to today's popular messages of social and political ideals[11] Te eruption of Vesuvius preserved graffiti in Pompeii, which includes Latin curses, magic spells, declarations of love, alphabets, political slogans, and famous literary quotes, providing insight into ancient Roman street life. One inscription gives the address of a woman named Novellia Primigenia of Nuceria, a prostitute, apparently of great beauty, whose services were much in demand. Another shows a phallus accompanied by the text, mansueta tene ("handle with care").

Disappointed love also found its way onto walls in antiquity:

Quisquis amat. veniat. Veneri volo frangere costas fustibus et lumbos debilitare deae. Si potest illa mihi tenerum pertundere pectus quit ego non possim caput illae frangere fuste?

Whoever loves, go to hell. I want to break Venus's ribs with a club and deform her hips. If she can break my tender heart why can't I hit her over the head?

Ancient tourists visiting the 5th-century citadel at Sigiriya in Sri Lanka scribbled over 1800 individual graffiti there between the 6th and 18th centuries. Etched on the surface of the Mirror Wall, they contain pieces of prose, poetry, and commentary. Te majority of these visitors appear to have been from the elite of society: royalty, officials, professions, and clergy. Tere were also soldiers, archers, and even some metalworkers. Te topics range from love to satire, curses, wit, and lament. Many demonstrate a very high level of literacy and a deep appreciation of art and poetry.Most of the graffiti refer to the frescoes of semi-nude females found there. One reads:

Wet with cool dew drops fragrant with perfume from the fowers came the gentle breeze jasmine and water lily dance in the spring sunshine side-long glances of the golden-hued ladies stab into my thoughts heaven itself cannot take my mind as it has been captivated by one lass among the fve hundred I have seen here.

Among the ancient political graﬃti examples were Arab satirist poems. Yazid al-Himyari, an Umayyad Arab and Persian poet, was most known for writing his political poetry on the walls between Sajistan and Basra, manifesting a strong hatred towards the Umayyad regime and its walis, and people used to read and circulate them very widely.[15][clarifcation needed]

Literacy or illiteracy often revealed in graffiti - Historic forms of graffiti have helped gain understanding into the lifestyles and languages of past cultures. Errors in spelling and grammar in these graffiti offer insight into the degree of literacy in Roman times and provide clues on the pronunciation of spoken Latin. Examples are CIL IV, 7838: Vettium Firmum / aed[ilem] quactiliar[ii] [sic] rog[ant]. Here, "qu" is pronounced "co". Te 83 pieces of graffiti found at CIL IV, 4706-85 are evidence of the ability to read and write at levels of society where literacy might not be expected. Te graffiti appear on a

379 peristyle which was being remodeled at the time of the eruption of Vesuvius by the architect Crescens. Te graffiti were left by both the foreman and his workers. Te brothel at CIL VII, 12, 18–20 contains more than 120 pieces of graffiti, some of which were the work of the prostitutes and their clients. Te gladiatorial academy at CIL IV, 4397 was scrawled with graffiti left by the gladiator Celadus Crescens (Suspirium puellarum Celadus thraex: "Celadus the Tracian makes the girls sigh.")

It was not only the Greeks and Romans who produced graffiti: the Maya site of Tikal in Guatemala contains examples of ancient Maya graffiti. Viking graffiti survive in Rome and at Newgrange Mound in Ireland, and a Varangian scratched his name (Halvdan) in runes on a banister in the Hagia Sophia at Constantinople. Tese early forms of graffiti have contributed to the understanding of lifestyles and languages of past cultures.

Graﬃti, known as Tacherons, were frequently scratched on Romanesque Scandinavian church walls.[17] When Renaissance artists such as Pinturicchio, Raphael, Michelangelo, Ghirlandaio, or Filippino Lippi descended into the ruins of Nero's Domus Aurea, they carved or painted their names and returned to initiate the grottesche style of decoration.[18][19]

Tere are also examples of graﬃti occurring in American history, such as Independence Rock, a national landmark along the Oregon Trail.[20]

Later, French soldiers carved their names on monuments during the Napoleonic campaign of Egypt in the 1790s.[21] Lord Byron's survives on one of the columns of the Temple of Poseidon at Cape Sounion in Attica, Greece.[22]

Graffiti writing is often intertwined with hip hop culture[23] and the myriad international styles derived from Philadelphia and New York City Subway graffiti. However, there are many other instances of notable graffiti in the twentieth century. Graffiti have long appeared on building walls, in latrines, railroad boxcars, subways, and bridges. Te oldest known example of modern graffiti are the "monikers" found on traincars created by hobos and railworkers since the late 1800s. Te Bozo Texino monikers were documented by flmmaker Bill Daniel in his 2005 flm, Who is Bozo Texino?.[24][25]

Some graﬃti have their own poignancy. In World War II, an inscription on a wall at the fortress of Verdun was seen as an illustration of the US response twice in a generation to the wrongs of the Old World:[26][27]

During World War II and for decades after, the phrase "Kilroy was here" with an accompanying illustration was widespread throughout the world, due to its use by American troops and ultimately fltering into American popular culture. Shortly after the death of Charlie Parker (nicknamed "Yardbird" or "Bird"), graffiti began appearing around New York with the words "Bird Lives".[28] Te student protests and general strike of May 1968 saw Paris bedecked in revolutionary, anarchistic, and situationist slogans such as L'ennui est contre-révolutionnaire ("Boredom is counterrevolutionary") expressed in painted graffiti, poster art, and stencil art. At the time in the US, other political phrases (such as "Free Huey" about Black Panther Huey Newton) became briefy popular as graffiti in limited areas, only to be forgotten. A popular graffito of the early 1970s was "Dick Nixon Before He Dicks You", refecting the hostility of the youth culture to that US president.

Rock and roll graffiti is a signifcant subgenre. A famous graffito of the twentieth century was the inscription in the London tube reading "Clapton is God" in a link to the guitarist Eric Clapton. Te phrase was spray-painted by an admirer on a wall in an Islington station on the Underground in the autumn of 1967. Te graffito was captured in a photograph, in which a dog is urinating on the wall.

Graffiti also became associated with the anti-establishment punk rock movement beginning in the 1970s. Bands such as Black Flag and Crass (and their followers) widely stenciled their names and logos, while many punk night clubs, squats, and hangouts are famous for their graffiti. In the late 1980s the upside down Martini glass that was the tag for punk band Missing Foundation was the most ubiquitous graffito in lower Manhattan

In 1979, graffitists Lee Quinones and Fab 5 Freddy were given a gallery opening in Rome by art dealer Claudio Bruni. For many outside of New York, it was their frst encounter with their art form. Fab 5 Freddy's friendship with Debbie Harry infuenced Blondie's single "Rapture" (Chrysalis, 1981), the video of which featured Jean-Michel Basquiat, and offered many their frst glimpse of a depiction of elements of graffiti in hip hop culture. JaJaJa toured Germany, Switzerland, Belgium, and Holland with a large graffiti canvas as a backdrop.[29] Charlie Ahearn's independently released fction flm Wild Style (Wild Style, 1983), the early PBS documentary Style Wars (1983), hit songs such as "Te Message" and "Planet Rock" and their accompanying music videos (both 1982) contributed to a growing interest outside New York in all aspects of hip hop.[23]

Style Wars depicted not only famous graffitists such as Skeme, Dondi, MinOne, and ZEPHYR, but also reinforced graffiti's role within New York's emerging hip- hop culture by incorporating famous early break-dancing groups such as Rock Steady Crew into the flm and featuring rap in the soundtrack. Although many officers of the New York City Police Department found this flm to be controversial, Style Wars is still recognized as the most prolifc flm representation of what was going on

380 within the young hip hop culture of the early 1980s.[30] Fab 5 Freddy and Futura 2000 took hip hop graﬃti to Paris and London as part of the New York City Rap Tour in 1983.[31] Hollywood also paid attention, consulting writers such as PHASE 2 as it depicted the culture and gave it international exposure in movies such as Beat Street (Orion, 1984).

Stencil graffiti emerges Tis period also saw the emergence of the new stencil graffiti genre. Some of the frst examples were created in 1981 by graffitists Blek le Rat in Paris, in 1982 by Jef Aerosol in Tours (France);[citation needed] by 1985 stencils had appeared in other cities including New York City, Sydney, and Melbourne, where they were documented by American photographer Charles Gatewood and Australian photographer Rennie Ellis.[32]

Graffiti as a memorial People often leave their traces in wet cement or concrete. Tis type of graffito often commemorates the mutual commitment of a couple, or simply records a person's presence at a particular moment. Often this type of graffito is dated and is left untouched for decades, offering a look into local historical minutiae. [citation needed]

Commercialization and entrance into mainstream pop culture Main article: Commercial graﬃti With the popularity and legitimization of graﬃti has come a level of commercialization. In 2001, computer giant IBM launched an advertising campaign in Chicago and San Francisco which involved people spray painting on sidewalks a peace symbol, a heart, and a penguin (Linux mascot), to represent "Peace, Love, and Linux." Due to laws forbidding it, some of the "street artists" were arrested and charged with vandalism, and IBM was fned more than US$120,000 for punitive damages and clean-up costs.[33][34]

In 2005, a similar ad campaign was launched by Sony and executed by TATS CRU in New York, Chicago, Atlanta, Philadelphia, Los Angeles, and Miami, to market its handheld PSP gaming system. In this campaign, taking notice of the legal problems of the IBM campaign, Sony paid building owners for the rights to paint on their buildings "a collection of dizzy-eyed urban kids playing with the PSP as if it were a skateboard, a paddle, or a rocking horse".[34]

Gamer culture Along with the commercial growth has come the rise of video games also depicting graffiti, usually in a positive aspect – for example, the Jet Set Radio series (2000–2003) tells the story of a group of teens fghting the oppression of a totalitarian police force that attempts to limit the graffitists' freedom of speech. In plotlines mirroring the negative reaction of non- commercial artists to the commercialization of the art form by companies such as IBM (and, later, Sony itself) the Rakugaki Ōkoku series (2003–2005) for Sony's PlayStation 2 revolves around an anonymous hero and his magically imbued-with-life graffiti creations as they struggle against an evil king who only allows art to be produced which can beneft him. Following the original roots of modern graffiti as a political force came another game title, Marc Eckō's Getting Up: Contents Under Pressure (2006), featuring a story line involving fghting against a corrupt city and its oppression of free speech, as in the Jet Set Radio series.

Other games which feature graffiti include Bomb the World (2004), an online graffiti simulation created by graffitists Klark Kent where users can paint trains virtually at 20 locations worldwide, and Super Mario Sunshine (2002), in which the hero, Mario must clean the city of graffiti left by the villain, Bowser Jr. in a plotline which evokes the successes of the Anti-Graffiti Task Force of New York's Mayor Rudolph Giuliani (a manifestation of the "broken window theory") or those of the "Graffiti Blasters" of Chicago's Mayor Richard M. Daley.

Numerous other non-graffiti-centric video games allow the player to produce graffiti (such as the Half-Life series, the Tony Hawk's series, Te Urbz: Sims in the City, Rolling, and Grand Teft Auto: San Andreas). Counter-Strike, which is a Half- Life mod, allows users to create their own graffiti tags to use in the game. Many other titles contain in-game depictions of graffiti, including Te Darkness, Double Dragon 3: Te Rosetta Stone, NetHack, Samurai Champloo: Sidetracked, Te World Ends with You, Te Warriors, Just Cause, Portal, and various examples of Virtual Graffiti. Tere also exist games where the term "graffiti" is used as a synonym for "drawing" (such as Yahoo! Graffiti, Graffiti, etc.).

Advocates Marc Ecko, an urban clothing designer, has been an advocate of graﬃti as an art form during this period, stating that "Graﬃti is without question the most powerful art movement in recent history and has been a driving inspiration throughout my career."[35]

381 Henry Chalfant is one of the foremost advocates of modern graffiti, having produced the documentary flm Style Wars and co-authored the books Subway Art and Spray Can Art. His most recent work, Henry Chalfant's Graffiti Archive: New York City's Subway Art and Artists displays his over 800 photographs of New York City Subway Graffiti Art.[36]

Keith Haring was another well-known graffitists who brought Pop Art and graffiti to the commercial mainstream. In the 1980s, Haring opened his frst Pop Shop: a store that offered everyone access to his works, which until then could only be found spray-painted on city walls. Pop Shop offered commodities such as bags and t-shirts. Haring explained that "Te Pop Shop makes my work accessible. It's about participation on a big level, the point was that we didn't want to produce things that would cheapen the art. In other words, this was still art as statement."[37]

Graﬃti have become a common stepping stone for many members of both the art and design communities in North America and abroad. Within the United States graﬃtists such as Mike Giant, Pursue, Rime, Noah, and countless others have made careers in skateboard, apparel, and shoe design for companies such as DC Shoes, Adidas, Rebel8, Osiris, or Circa[38] Meanwhile, there are many others such as DZINE, Daze, Blade, and Te Mac who have made the switch to being gallery artists, often not even using their initial medium, spray paint.[38]

Te modern-day graffitists can be found with an arsenal of various materials that allow for a successful production of a piece. [45] Tis includes such techniques as scribing. However, spray paint in aerosol cans is the number one medium for graffiti. From this commodity comes different styles, technique, and abilities to form master works of graffiti. Spray paint can be found at hardware and art stores and comes in virtually every color.

Stencil graﬃti is created by cutting out shapes and designs in a stiﬀ material (such as cardboard or subject folders) to form an overall design or image. Te stencil is then placed on the "canvas" gently and with quick, easy strokes of the aerosol can, the image begins to appear on the intended surface.

Graﬃti application in India using natural pigments (mostly charcoal, plant saps, and dirt)

Spiderweb Yarnbomb Installation by Stephen Duneier both hides and highlights previous graffiti. Modern graffiti art often incorporates additional arts and technologies. For example, Graffiti Research Lab has encouraged the use of projected images and magnetic light-emitting diodes (throwies) as new media for graffitists. Yarnbombing is another recent form of graffiti. Yarnbombers occasionally target previous graffiti for modifcation, which had been avoided among the majority of graffitists.

Tagging

Some of the most common styles of graffiti have their own names. A tag is the most basic writing of an artist's name; it is simply a handstyle. A graffiti writer's tag is his or her personalized signature. Tagging is often the example given when opponents of graffiti refer to any acts of handstyle graffiti writing (it is by far the most common form of graffiti). Tags can contain subtle and sometimes cryptic messages, and may incorporate the artist's crew initials or other letters.

One form of tagging, known as pissing, involves taking a refllable fre-extinguisher and replacing the contents with paint, allowing for tags as high as approximately 20 feet (6.1 m). Aiming and keeping a handstyle steady in this form of tagging is very diﬃcult, usually coming out wavy and sloppy.

Another form is the throw-up, also known as a bombing, which is normally painted very quickly with two or three colors, sacrifcing aesthetics for speed. Trow- ups can also be outlined on a surface with one color. A piece is a more elaborate representation of the artist's name, incorporating more stylized letters, usually incorporating a much larger range of colors. Tis is more time-consuming and increases the likelihood of the artist getting caught.

Trow-ups and a piece under a railway bridge in Poland. A blockbuster or roller is a large piece, almost always done in a block-shaped style, done simply to cover a large area solidly with two contrasting colors, sometimes with the whole purpose of blocking other writers from painting on the same wall. Tese are usually accomplished with extended paint rollers and gallons of cheap exterior paint.

A more complex style is wildstyle, a form of graﬃti usually involving interlocking letters and connecting points. Tese pieces are often harder to read by non- graﬃtists as the letters merge into one another in an often-undecipherable manner.

Some artists also use self-adhesive stickers as a quick way to do catch ups. While certain critics from within graﬃti culture consider this lazy, stickers can be quite detailed in their own right and often, are used in conjunction with other materials.

382 Sticker tags are commonly executed on blank postage stickers, as these can easily be acquired with no cost on the writer's part.

Many graﬃtists believe that doing complex pieces involves too great an investment of time to justify the practice. Doing a piece can take (depending on experience and size) from 30 minutes to months on end, as was the case for Saber MSK while working on the world's largest graﬃti piece on the LA river.

Another graﬃtists can go over a piece in a matter of minutes with a simple throw-up. Tis was exemplifed by the writer "CAP" in the documentary Style Wars, who, other writers complain, ruins pieces with his quick throw ups. Tis became known as capping and often is done when there is a "beef", or confict between writers.

A number of recent examples of graﬃti make use of hashtags.

Teories on the use of graﬃti by avant-garde artists have a history dating back at least to the Scandinavian Institute of Comparative Vandalism in 1961.[citation needed]

Many contemporary analysts and even art critics have begun to see artistic value in some graﬃti and to recognize it as a form of public art. According to many art researchers, particularly in the Netherlands and in Los Angeles, that type of public art is, in fact an eﬀective tool of social emancipation or, in the achievement of a political goal.[48]

In times of confict, such murals have offered a means of communication and self-expression for members of these socially, ethnically, or racially divided communities, and have proven themselves as effective tools in establishing dialog and thus, of addressing cleavages in the long run. Te Berlin Wall was also extensively covered by graffiti refecting social pressures relating to the oppressive Soviet rule over the GDR.

Many artists involved with graffiti are also concerned with the similar activity of stenciling. Essentially, this entails stenciling a print of one or more colors using spray-paint. Recognized while exhibiting and publishing several of her coloured stencils and paintings portraying the Sri Lankan Civil War and urban Britain in the early 2000s, graffitists Mathangi Arulpragasam, aka M.I.A., has also become known for integrating her imagery of political violence into her music videos for singles "Galang" and "Bucky Done Gun", and her cover art. Stickers of her artwork also often appear around places such as London in Brick Lane, stuck to lamp posts and street signs, she having become a muse for other graffitists and painters worldwide in cities including Seville.[49] graffitists John Fekner, called "caption writer to the urban environment, adman for the opposition" by writer Lucy Lippard,[50] was involved in direct art interventions within New York City's decaying urban environment in the mid-1970s through the 1980s. Fekner is known for his word installations targeting social and political issues, stenciled on buildings throughout New York.

Many graﬃtists choose to protect their identities and remain anonymous or to hinder prosecution.

With the commercialization of graffiti (and hip hop in general), in most cases, even with legally painted "graffiti" art, graffitists tend to choose anonymity. Tis may be attributed to various reasons or a combination of reasons. Graffiti still remains the one of four hip hop elements that is not considered "performance art" despite the image of the "singing and dancing star" that sells hip hop culture to the mainstream. Being a graphic form of art, it might also be said that many graffitists still fall in the category of the introverted archetypal artist.

Banksy is one of the world's most notorious and popular street artists who continues to remain faceless in today's society. [51] He is known for his political, anti- war stencil art mainly in Bristol, England, but his work may be seen anywhere from Los Angeles to Palestine. In the UK, Banksy is the most recognizable icon for this cultural artistic movement and keeps his identity a secret to avoid arrest. Much of Banksy's artwork may be seen around the streets of London and surrounding suburbs, although he has painted pictures throughout the world, including the Middle East, where he has painted on Israel's controversial West Bank barrier with satirical images of life on the other side. One depicted a hole in the wall with an idyllic beach, while another shows a mountain landscape on the other side. A number of exhibitions also have taken place since 2000, and recent works of art have fetched vast sums of money. Banksy's art is a prime example of the classic controversy: vandalism vs. art. Art supporters endorse his work distributed in urban areas as pieces of art and some councils, such as Bristol and Islington, have oﬃcially protected them, while oﬃcials of other areas have deemed his work to be vandalism and have removed it.

Pixnit is another artist who chooses to keep her identity from the general public.[52] Her work focuses on beauty and design aspects of graﬃti as opposed to Banksy's anti-government shock value. Her paintings are often of fower designs above shops and stores in her local urban area of Cambridge, Massachusetts. Some store owners endorse her work and encourage others

383 to do similar work as well. "One of the pieces was left up above Steve's Kitchen, because it looks pretty awesome"- Erin Scott, the manager of New England Comics in Allston, Massachusetts.[citation needed]

Inscription in Pompeii lamenting a frustrated love, "Whoever loves, let him fourish, let him perish who knows not love, let him perish twice over whoever forbids love."

Black bloc members spray graffiti on a wall during an Iraq War Protest in Washington, D.C. Graffiti often has a reputation as part of a subculture that rebels against authority, although the considerations of the practitioners often diverge and can relate to a wide range of attitudes. It can express a political practice and can form just one tool in an array of resistance techniques. One early example includes the anarcho-punk band Crass, who conducted a campaign of stenciling anti-war, anarchist, feminist, and anti-consumerist messages throughout the London Underground system during the late 1970s and early 1980s.[53] In Amsterdam graffiti was a major part of the punk scene. Te city was covered with names such as "De Zoot", "Vendex", and "Dr Rat".[54] To document the graffiti a punk magazine was started that was called Gallery Anus. So when hip hop came to Europe in the early 1980s there was already a vibrant graffiti culture.

Te student protests and general strike of May 1968 saw Paris bedecked in revolutionary, anarchistic, and situationist slogans such as L'ennui est contre- révolutionnaire ("Boredom is counterrevolutionary") and Lisez moins, vivez plus ("Read less, live more"). While not exhaustive, the graﬃti gave a sense of the 'millenarian' and rebellious spirit, tempered with a good deal of verbal wit, of the strikers.

I think graﬃti writing is a way of defning what our generation is like. Excuse the French, we're not a bunch of p---- artists. Traditionally artists have been considered soft and mellow people, a little bit kooky. Maybe we're a little bit more like pirates that way. We defend our territory, whatever space we steal to paint on, we defend it fercely. —Sandra "Lady Pink" Fabara[55]

Te developments of graffiti art which took place in art galleries and colleges as well as "on the street" or "underground", contributed to the resurfacing in the 1990s of a far more overtly politicized art form in the subvertising, culture jamming, or tactical media movements. Tese movements or styles tend to classify the artists by their relationship to their social and economic contexts, since, in most countries, graffiti art remains illegal in many forms except when using non- permanent paint. Since the 1990s with the rise of Street Art, a growing number of artists are switching to non-permanent paints and non-traditional forms of painting[56][57] for a variety of reasons—but primarily because is it difficult for the police to apprehend them and for the courts to sentence or even convict a person for a protest that is as feeting and less intrusive than marching in the streets. In some communities, such impermanent works survive longer than works created with permanent paints because the community views the work in the same vein as that of the civil protester who marches in the street—such protest are impermanent, but effective nevertheless.

In some areas where a number of artists share the impermanence ideal, an informal competition develops: the length of time that a work escapes destruction is viewed as a measure of the respect the work garners in the community. A crude work that deserves little respect would be invariably removed immediately, while the most talented artists might have works last for days.

Contemporary practitioners, accordingly, have varied and often conficting practices. Some individuals, such as Alexander Brener, have used the medium to politicize other art forms, and have used the prison sentences enforced on them as a means of further protest.[58] Te practices of anonymous groups and individuals also vary widely, and practitioners by no means always agree with each other's practices. For example, the anti-capitalist art group the Space Hijackers did a piece in 2004 about the contradiction between the capitalistic elements of Banksy and his use of political imagery.[59][60]

On top of the political aspect of graffiti as a movement, political groups and individuals may also use graffiti as a tool to spread their point of view. Tis practice, due to its illegality, has generally become favored by groups excluded from the political mainstream (e.g. far-left or far-right groups) who justify their activity by pointing out that they do not have the money – or sometimes the desire – to buy advertising to get their message across, and that a "ruling class" or "establishment" controls the mainstream press, systematically excluding the radical and alternative point of view. Tis type of graffiti can seem crude; for example fascist supporters often scrawl swastikas and other Nazi images.

One innovative form of graffiti that emerged in the UK in the 1970s was devised by the Money Liberation Front (MLF), essentially a loose affiliation of underground press writers such as the poet and playwright Heathcote Williams and magazine editor and playwright Jay Jeff Jones. Tey initiated the use of paper currency as a medium for counterculture propaganda, overprinting banknotes, usually with a John Bull printing set. Although short lived, the MLF was representative of London's Ladbroke Grove centered alternative and literary community of the period. Te area was also a scene of considerable anti- establishment and humorous street graffiti, much of which is also produced by Williams.[61] In 2009, following the

384 elections in Iran, protesters (who regarded the electoral result as rigged) began to deface banknotes with slogans such as "Death to the dictator". In Colombia writing and drawing on banknotes has become increasingly popular, either to make political comments, for fun or as an artistic medium. Te national government has run advertising campaigns in an attempt to discourage the practice. In the UK there have been signs of an MLF resurgence with a number of banknotes in circulation being over-marked with protest slogans such as "Banks=Robbers", relating to the perceived culpability of banks in the fnancial crisis.

Both sides of the confict in Northern Ireland produce political graffiti. As well as slogans, Northern Irish political graffiti includes large wall paintings, referred to as murals. Along with the fying of fags and the painting of kerb stones, the murals serve a territorial purpose, often associated with gang use. Artists paint them mostly on house gables or on the Peace Lines, high walls that separate different communities.

Te murals often develop over an extended period and tend to stylization, with a strong symbolic or iconographic content. Loyalist murals often refer to historical events dating from the war between James II and William III in the late seventeenth century, whereas Republican murals usually refer to the more recent troubles.

Territorial graffiti marks urban neighborhoods with tags and logos to differentiate certain groups from others. Tese images are meant to show outsiders a stern look at whose turf is whose. Te subject matter of gang-related graffiti consists of cryptic symbols and initials strictly fashioned with unique calligraphies. Gang members use graffiti to designate membership throughout the gang, to differentiate rivals and associates and, most commonly, to mark borders which are both territorial and ideological.[62]

Graffiti may also be used as an offensive expression. Tis form of graffiti may be difficult to identify, as it is mostly removed by the local authority (as councils which have adopted strategies of criminalization also strive to remove graffiti quickly).[63] Terefore, existing racist graffiti is mostly more subtle and at frst sight, not easily recognized as "racist". It can then only be understood if one knows the relevant "local code" (social, historical, political, temporal, and spatial), which is seen as heteroglot and thus a 'unique set of conditions' in a cultural context.[64]

A spatial code for example, could be that there is a certain youth group in an area that is engaging heavily in racist activities. So, for residents (knowing the local code), a graffiti containing only the name or abbreviation of this gang already is a racist expression, reminding the offended people of their gang activities. Also a graffiti is in most cases, the herald of more serious criminal activity to come.[65] A person who does not know these gang activities would not be able to recognize the meaning of this graffiti. Also if a tag of this youth group or gang is placed on a building occupied by asylum seekers, for example, its racist character is even stronger.

By making the graﬃti less explicit (as adapted to social and legal constraints),[66] these drawings are less likely to be removed, but do not lose their threatening and oﬀensive character.[67]

Elsewhere, activists in Russia have used painted caricatures of local oﬃcials with their mouths as potholes, to show their anger about the poor state of the roads. [68] In Manchester, England a graﬃtists painted obscene images around potholes, which often resulted in their being repaired within 48 hours.[69]

A bronze work by Jonesy on a wall in Brick Lane (London). Diameter about 8 cm. In the early 1980s, the frst art galleries to show graﬃtists to the public were Fashion Moda in the Bronx, Now Gallery and Fun Gallery, both in the East Village, Manhattan.

A 2006 exhibition at the Brooklyn Museum displayed graffiti as an art form that began in New York's outer boroughs and reached great heights in the early 1980s with the work of Crash, Lee, Daze, Keith Haring, and Jean-Michel Basquiat. It displayed 22 works by New York graffitists, including Crash, Daze, and Lady Pink. In an article about the exhibition in the magazine Time Out, curator Charlotta Kotik said that she hoped the exhibition would cause viewers to rethink their assumptions about graffiti. Terrance Lindall, an artist and executive director of the Williamsburg Art and Historic Center, said regarding graffiti and the exhibition:

"Graﬃti is revolutionary, in my opinion", he says, "and any revolution might be considered a crime. People who are oppressed or suppressed need an outlet, so they write on walls—it's free."

From the 1970s onwards, Burhan Dogancay photographed urban walls all over the world; these he then archived for use as sources of inspiration for his painterly works. Te project today known as "Walls of the World" grew beyond even his own expectations and comprises about 30,000 individual images. It spans a period of 40 years across fve continents and 114

385 countries. In 1982, photographs from this project comprised a one-man exhibition titled "Les murs murmurent, ils crient, ils chantent..." (Te walls whisper, shout and sing ...) at the Centre Georges Pompidou in Paris.

In Australia, art historians have judged some local graffiti of sufficient creative merit to rank them frmly within the arts. Oxford University Press's art history text Australian Painting 1788–2000 concludes with a long discussion of graffiti's key place within contemporary visual culture, including the work of several Australian practitioners.

Between March and April 2009, 150 artists exhibited 300 pieces of graﬃti at the Grand Palais in Paris — a clear acceptance of the art form into the French art world.

Figurines by KAWS, featuring icons of pop culture, often with crossed-out eyes, run in limited editions and sell for thousands of dollars. World-renowned street artist Banksy directed a flm in 2010, Exit Trough the Gift Shop, which explored street art and commercialism.

Design

Design can have diﬀerent connotations in diﬀerent felds of application (see design disciplines below), but there are two basic meanings of design: as a verb and as a noun.

Design (as a verb: to design) is the intentional creation of a plan or specifcation for the construction of an object or system or for the implementation of an activity or process.

Design (as a noun: a design) can refer to such a plan or specifcation (e.g. a drawing or other document) or to the created object, etc., and features of it such as aesthetic, functional, economic or socio-political.

Te process of creating a design can be brief (a quick sketch) or lengthy and complicated, involving considerable research, negotiation, refection, modelling, interactive adjustment and re-design. In some cases, the direct construction of an object without an explicit prior plan (such as in craftwork and some engineering, coding, and graphic design) is also considered to be a design activity.

"Everyone designs who devises courses of action aimed at changing existing situations into preferred ones."[1] More formally design has been defned as follows:

(noun) a specifcation of an object, manifested by an agent, intended to accomplish goals, in a particular environment, using a set of primitive components, satisfying a set of requirements, subject to constraints; (verb, transitive) to create a design, in an environment (where the designer operates)[2]

Another defnition for design is "a roadmap or a strategic approach for someone to achieve a unique expectation. It defnes the specifcations, plans, parameters, costs, activities, processes and how and what to do within legal, political, social, environmental, safety and economic constraints in achieving that objective."[3]

Here, a "specifcation" can be manifested as either a plan or a fnished product, and "primitives" are the elements from which the design object is composed.

Te person designing is called a designer, which is also a term used for people who work professionally in one of the various design areas usually specifying which area is being dealt with (such as a textile designer, fashion designer, product designer, concept designer, web designer or interior designer). A designer's sequence of activities is called a design process while the scientifc study of design is called design science.[1][4][5][6]

Another defnition of design is planning to manufacture an object, system, component or structure. Tus the word "design" can be used as a noun or a verb. In a broader sense, design is an applied art and engineering that integrates with technology.

While the defnition of design is fairly broad, design has a myriad of specifcations that professionals utilize in their felds. Major examples of design are architectural blueprints, engineering drawings, business processes, circuit diagrams, and sewing patterns[7]

Tere are countless philosophies for guiding design as design values and its accompanying aspects within modern design vary, both between diﬀerent schools of thought[which?] and among practicing designers.[26] Design philosophies are usually for determining design goals. A design goal may range from solving the least signifcant individual problem of the smallest element, to the most holistic infuential utopian goals. Design goals are usually for guiding design. However, conficts over

386 immediate and minor goals may lead to questioning the purpose of design, perhaps to set better long term or ultimate goals. John Heskett, a 20th- century British writer on design claimed, "Design, stripped to its essence, can be defned as the human nature to shape and make our environment in ways without precedent in nature, to serve our needs and give meaning to our lives."[27]

Philosophies for guiding design Design philosophies are fundamental guiding principles that dictate how a designer approaches his/her practice. Refections on material culture and environmental concerns (sustainable design) can guide a design philosophy. One example is the First Tings First manifesto which was launched within the graphic design community and states "We propose a reversal of priorities in favor of more useful, lasting and democratic forms of communication – a mindshift away from product marketing and toward the exploration and production of a new kind of meaning. Te scope of debate is shrinking; it must expand. Consumerism is running uncontested; it must be challenged by other perspectives expressed, in part, through the visual languages and resources of design."[28]

In Te Sciences of the Artifcial by polymath Herbert A. Simon, the author asserts design to be a meta-discipline of all professions. "Engineers are not the only professional designers. Everyone designs who devises courses of action aimed at changing existing situations into preferred ones. Te intellectual activity that produces material artifacts is no diﬀerent fundamentally from the one that prescribes remedies for a sick patient or the one that devises a new sales plan for a company or a social welfare policy for a state. Design, so construed, is the core of all professional training; it is the principal mark that distinguishes the professions from the sciences. Schools of engineering, as well as schools of architecture, business, education, law, and medicine, are all centrally concerned with the process of design."[1]

Substantial disagreement exists concerning how designers in many felds, whether amateur or professional, alone or in teams, produce designs. Kees Dorst and Judith Dijkhuis, both designers themselves, argued that "there are many ways of describing design processes" and discussed "two basic and fundamentally diﬀerent ways",[8] both of which have several names. Te prevailing view has been called "the rational model",[9] "technical problem solving"[10] and "the reason-centric perspective".[11] Te alternative view has been called "refection-in-action",[10] "evolutionary design",[6] "co-evolution", [12] and "the action- centric perspective".[11]

Te rational model Te rational model was independently developed by Herbert A. Simon,[13][1] an American scientist, and Gerhard Pahl and Wolfgang Beitz, two German engineering design theorists.[14] It posits that: designers attempt to optimize a design candidate for known constraints and objectives, the design process is plan-driven, the design process is understood in terms of a discrete sequence of stages. Te rational model is based on a rationalist philosophy[9] and underlies the waterfall model,[15] systems development life cycle,[16] and much of the engineering design literature.[17] According to the rationalist philosophy, design is informed by research and knowledge in a predictable and controlled manner.

Example sequence of stages Typical stages consistent with the rational model include the following:

Pre-production design Design brief or Parti pris – an early (often the beginning) statement of design goals Analysis – analysis of current design goals Research – investigating similar design solutions in the feld or related topics Specifcation – specifying requirements of a design solution for a product (product design specifcation)[18] or service. Problem solving – conceptualizing and documenting design solutions Presentation – presenting design solutions Design during production Development – continuation and improvement of a designed solution Testing – in situ testing of a designed solution Post-production design feedback for future designs Implementation – introducing the designed solution into the environment Evaluation and conclusion – summary of process and results, including constructive criticism and suggestions for future improvements Redesign – any or all stages in the design process repeated (with corrections made) at any time before, during, or after production. Each stage has many associated best practices.[19]

387 Criticism of the rational model Te rational model has been widely criticized on two primary grounds:

Designers do not work this way – extensive empirical evidence has demonstrated that designers do not act as the rational model suggests.[20][11][10] Unrealistic assumptions – goals are often unknown when a design project begins, and the requirements and constraints continue to change.[9][21] Te action-centric model Te action-centric perspective is a label given to a collection of interrelated concepts, which are antithetical to the rational model.[11] It posits that: designers use creativity and emotion to generate design candidates, the design process is improvised, no universal sequence of stages is apparent – analysis, design and implementation are contemporary and inextricably linked[11] Te action-centric perspective is based on an empiricist philosophy and broadly consistent with the agile approach[22] and amethodical development.[23] Substantial empirical evidence supports the veracity of this perspective in describing the actions of real designers.[20] Like the rational model, the action-centric model sees design as informed by research and knowledge. However, research and knowledge are brought into the design process through the judgment and common sense of designers – by designers "thinking on their feet" – more than through the predictable and controlled process stipulated by the rational model.

Descriptions of design activities At least two views of design activity are consistent with the action-centric perspective. Both involve three basic activities.

In the refection-in-action paradigm, designers alternate between "framing", "making moves", and "evaluating moves". "Framing" refers to conceptualizing the problem, i.e., defning goals and objectives. A "move" is a tentative design decision. Te evaluation process may lead to further moves in the design.[10]

In the sensemaking–coevolution–implementation framework, designers alternate between its three titular activities. Sensemaking includes both framing and evaluating moves. Implementation is the process of constructing the design object. Coevolution is "the process where the design agent simultaneously refnes its mental picture of the design object based on its mental picture of the context, and vice versa".[11]

Te concept of the design cycle is understood as a circular time structure,[24] which may start with the thinking of an idea, then expressing it by the use of visual or verbal means of communication (design tools), the sharing and perceiving of the expressed idea, and fnally starting a new cycle with the critical rethinking of the perceived idea. Anderson points out that this concept emphasizes the importance of the means of expression, which at the same time are means of perception of any design ideas.[2

Today, the term design is widely associated with the applied arts as initiated by Raymond Loewy and teachings at the Bauhaus and Ulm School of Design (HfG Ulm) in Germany during the 20th century.

Te boundaries between art and design are blurred, largely due to a range of applications both for the term 'art' and the term 'design'. Applied arts has been used as an umbrella term to defne felds of industrial design, graphic design, fashion design, etc. Te term 'decorative arts' is a traditional term used in historical discourses to describe craft objects, and also sits within the umbrella of applied arts. In graphic arts (2D image making that ranges from photography to illustration), the distinction is often made between fne art and commercial art, based on the context within which the work is produced and how it is traded.

To a degree, some methods for creating work, such as employing intuition, are shared across the disciplines within the applied arts and fne art. Mark Getlein, writer, suggests the principles of design are "almost instinctive", "built-in", "natural", and part of "our sense of 'rightness'." However, the intended application and context of the resulting works will vary greatly.

A drawing for a booster engine for steam locomotives. Engineering is applied to design, with emphasis on function and the utilization of mathematics and science.

Design is the creation of a plan or convention for the construction of an object, system or measurable human interaction (as in architectural blueprints, engineering drawings, business processes, circuit diagrams, and sewing patterns). Design has diﬀerent connotations in diﬀerent felds (see design disciplines below). In some cases, the direct construction of an object (as in pottery, engineering, management, coding, and graphic design) is also considered to use design thinking.

388 Designing often necessitates considering the aesthetic, functional, economic, and sociopolitical dimensions of both the design object and design process. It may involve considerable research, thought, modeling, interactive adjustment, and redesign. Meanwhile, diverse kinds of objects may be designed, including clothing, graphical user interfaces, products, skyscrapers, corporate identities, business processes, and even methods or processes of designing.

Tus "design" may be a substantive referring to a categorical abstraction of a created thing or things (the design of something), or a verb for the process of creation as is made clear by grammatical context.

Design as a process Substantial disagreement exists concerning how designers in many felds, whether amateur or professional, alone or in teams, produce designs. Kees Dorst and Judith Dijkhuis, both designers themselves, argued that "there are many ways of describing design processes" and discussed "two basic and fundamentally diﬀerent ways", both of which have several names. Te prevailing view has been called "the rational model", "technical problem solving" and "the reason-centric perspective". Te alternative view has been called "refection-in-action", "evolutionary design", “co-evolution", and "the action-centric perspective”.

Within the Bauhaus movement, the reigning principles were unity of form and function, the idea that design is in service of the community, and a belief in the perfection and eﬃciency of geometry. Its core objective was a radical concept: to reimagine the material world to refect the unity of all the arts.

"Form follows function" is the principle that the form art takes should be based upon its intent and purpose. ... Whether the design is functional, decorative, or alludes to the infrastructure of an object, Form and Function explores the relationship between the form of art and its function or purpose.

Te rational model Te rational model was independently developed by Herbert A. Simon, an American scientist, and Gerhard Pahl and Wolfgang Beitz, two German engineering design theorists. It posits that: designers attempt to optimize a design candidate for known constraints and objectives, the design process is plan-driven, the design process is understood in terms of a discrete sequence of stages. Te rational model is based on a rationalist philosophy and underlies the waterfall model, systems development life cycle, and much of the engineering design literature. According to the rationalist philosophy, design is informed by research and knowledge in a predictable and controlled manner.

Philosophies and studies of design Tere are countless philosophies for guiding design as design values and its accompanying aspects within modern design vary, both between diﬀerent schools of thought and among practicing designers. Design philosophies are usually for determining design goals. A design goal may range from solving the least signifcant individual problem of the smallest element, to the most holistic infuential utopian goals. Design goals are usually for guiding design. However, conficts over immediate and minor goals may lead to questioning the purpose of design, perhaps to set better long term or ultimate goals. John Heskett, a 20th-century British writer on design claimed, "Design, stripped to its essence, can be defned as the human nature to shape and make our environment in ways without precedent in nature, to serve our needs and give meaning to our lives."

389 distinguishes the professions from the sciences. Schools of engineering, as well as schools of architecture, business, education, law, and medicine, are all centrally concerned with the process of design."

A design approach is a general philosophy that may or may not include a guide for specifc methods. Some are to guide the overall goal of the design. Other approaches are to guide the tendencies of the designer. A combination of approaches may be used if they don't confict.

Te relationship between design and production is one of planning and executing. In theory, the plan should anticipate and compensate for potential problems in the execution process. Design involves problem-solving and creativity. In contrast, production involves a routine or pre-planned process. A design may also be a mere plan that does not include a production or engineering processes although a working knowledge of such processes is usually expected of designers. In some cases, it may be unnecessary or impractical to expect a designer with a broad multidisciplinary knowledge required for such designs to also have a detailed specialized knowledge of how to produce the product.

Design and production are intertwined in many creative professional careers, meaning problem-solving is part of execution and the reverse. As the cost of rearrangement increases, the need for separating design from production increases as well. For example, a high-budget project, such as a skyscraper, requires separating (design) architecture from (production) construction. A Low-budget project, such as a locally printed oﬃce party invitation fyer, can be rearranged and printed dozens of times at the low cost of a few sheets of paper, a few drops of ink, and less than one hour's pay of a desktop publisher.

Tis is not to say that production never involves problem-solving or creativity, nor that design always involves creativity. Designs are rarely perfect and are sometimes repetitive. Te imperfection of a design may task a production position (e.g. production artist, construction worker) with utilizing creativity or problem-solving skills to compensate for what was overlooked in the design process. Likewise, a design may be a simple repetition (copy) of a known preexisting solution, requiring minimal, if any, creativity or problem-solving skills from the designer

Graphic design is the process of visual communication and problem-solving using one or more of typography, photography and illustration. Te feld is considered a subset of visual communication and communication design, but sometimes the term "graphic design" is used synonymously. Graphic designers create and combine symbols, images and text to form visual representations of ideas and messages. Tey use typography, visual arts and page layout techniques to create visual compositions. Common uses of graphic design include corporate design (logos and branding), editorial design (magazines, newspapers and books), wayfnding or environmental design, advertising, web design, communication design, product packaging and signage.

Te term graphic design was coined by William Addison Dwiggins in 1922.However, the origins of graphic design can be traced from the origins of human existence, from the caves of Lascaux, to Rome's Trajan's Column to the illuminated manuscripts of the Middle Ages, to the neon lights of Ginza, Tokyo. In "Babylon, artisans pressed cuneiform inscriptions into clay bricks or tablets which were used for construction. Te bricks gave information such as the name of the reigning monarch, the builder, or some other dignitary". Tis was the frst known road sign announcing the name of the governor of a state or mayor of the city. Te Egyptians developed communication by hieroglyphics that used picture symbols dating as far back as 136 B.C. found on the Rosetta Stone. "Te Rosetta stone, found by one of Napoleon's engineers was an advertisement for the Egyptian ruler, Ptolemy as the "true Son of the Sun, the Father of the Moon, and the Keeper of the Happiness of Men"" Te Egyptians also invented papyrus, paper made from reeds found along the Nile, on which they transcribed advertisements more common among their people at the time. During the "Dark Ages", from 500 AD to 1450 AD, monks created elaborate, illustrated manuscripts.

In both its lengthy history and in the relatively recent explosion of visual communication in the 20th and 21st centuries, the distinction between advertising, art, graphic design and fne art has disappeared. Tey share many elements, theories, principles, practices, languages and sometimes the same benefactor or client. In advertising, the ultimate objective is the sale of goods and services. In graphic design, "the essence is to give order to information, form to ideas, expression, and feeling to artifacts that document human experience.”

A craft or trade is a pastime or a profession that requires particular skills and knowledge of skilled work. In a historical sense, particularly the Middle Ages and earlier, the term is usually applied to people occupied in small-scale production of goods, or their maintenance, for example by tinkers. Te traditional term craftsman is nowadays often replaced by artisan and rarely by craftsperson (craftspeople).

390 Historically, the more specialized crafts with high value products tended to concentrate in urban centers and formed guilds. Te skill required by their professions and the need to be permanently involved in the exchange of goods often demanded a generally higher level of education, and craftsmen were usually in a more privileged position than the peasantry in societal hierarchy. Te households of craftsmen were not as self-suﬃcient as those of people engaged in agricultural work and therefore had to rely on the exchange of goods. Some crafts, especially in areas such as pottery, woodworking, and the various stages of textile production, could be practiced on a part-time basis by those also working in agriculture, and often formed part of village life.

Once an apprentice of a craft had fnished his apprenticeship, he would become a journeyman searching for a place to set up his own shop and make a living. After he set up his own shop, he could then call himself a master of his craft.

Tis system of a stepwise approach to mastery of a craft, which includes the obtainment of a certain amount of education and the learning of skills, has survived in some countries of the world until today. But crafts have undergone deep structural changes during and since the end of the Industrial Revolution. Te mass production of goods by large-scale industry has limited crafts to market segments in which industry's modes of functioning or its mass-produced goods would not or cannot satisfy the preferences of potential buyers. Moreover, as an outcome of these changes, craftspeople today increasingly make use of semi-fnished components or materials and adapt these to their customers' requirements or demands and, if necessary, to the environments of their customers. Tus, they participate in a certain division of labour between industry and craft.

Tere are three aspects to human creativity - Art, Crafts, and Science. Roughly determined, art relies upon intuitive sensing, vision and expression, crafts upon sophisticated technique and science upon knowledge.

Handicraft is the "traditional" main sector of the crafts, it is a type of work where useful and decorative devices are made completely by hand or by using only simple tools. Usually the term is applied to traditional means of making goods. Te individual artisanship of the items is a paramount criterion, such items often have cultural and/or religious signifcance. Items made by mass production or machines are not handicraft goods. Handicraft goods are made with craft production processes.

Te beginning of crafts in areas like the Ottoman Empire involved the governing bodies requiring members of the city who were skilled at creating goods to open shops in the center of town. Tese people slowly stopped acting as subsistence farmers (who created goods in their own homes to trade with neighbors) and began to represent what we think of a "craftsman" today.[1]

In recent years, crafts and craftspeople have slowly been gaining momentum as a subject of academic study. Stephanie Bunn was an artist before she became an anthropologist, and she went on to develop an academic interest on the process of craft - arguing that what happens to an object before it becomes a 'product' is an area worthy of study. [2]

Te term crafts is often used to describe the family of artistic practices within the family decorative arts that traditionally are defned by their relationship to functional or utilitarian products (such as sculptural forms in the vessel tradition) or by their use of such natural media as wood, clay, ceramics, glass, textiles, and metal.

Crafts practiced by independent artists working alone or in small groups are often referred to as studio craft. Studio craft includes studio pottery, metal work, weaving, wood turning, paper and other forms of wood working, glass blowing, and glass art.

A tradesperson is a skilled manual worker in a particular trade or craft. Economically and socially, a tradesperson's status is considered between a laborer and a professional, with a high degree of both practical and theoretical knowledge of their trade. In cultures where professional careers are highly prized, there can be a shortage of skilled manual workers, leading to lucrative niche markets in the trades.

Design and engineering

In engineering, design is a component of the engineering process. Many overlapping methods and processes can be seen when comparing Product design, Industrial design and Engineering. Te American Heritage Dictionary defnes design as: "To conceive or fashion in the mind; invent," and "To formulate a plan", and defnes engineering as: "Te application of scientifc and mathematical principles to practical ends such as the design, manufacture, and operation of eﬃcient and economical structures, machines, processes, and systems.". Both are forms of problem-solving with a defned distinction being the application of "scientifc and mathematical principles". Te increasingly scientifc focus of engineering in practice, however, has raised the importance of new more "human-centered" felds of design. How much science is applied in a design is a question of what is considered "science". Along with the question of what is considered science, there is social science

391 versus natural science. Scientists at Xerox PARC made the distinction of design versus engineering at "moving minds" versus "moving atoms" (probably in contradiction to the origin of term "engineering - engineer" from Latin "in genio" in meaning of a "genius" what assumes existence of a "mind" not of an "atom").

Engineering

Te creative application of scientifc principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specifc operating conditions; all as respects an intended function, economics of operation and safety to life and property.

Relief map of the Citadel of Lille, designed in 1668 by Vauban, the foremost military engineer of his age. Engineering has existed since ancient times, when humans devised inventions such as the wedge, lever, wheel and pulley.

Te term engineering is derived from the word engineer, which itself dates back to 1390 when an engine'er (literally, one who operates an engine) referred to "a constructor of military engines." In this context, now obsolete, an "engine" referred to a military machine, i.e., a mechanical contraption used in war (for example, a catapult). Notable examples of the obsolete usage which have survived to the present day are military engineering corps, e.g., the U.S. Army Corps of Engineers.

Te word "engine" itself is of even older origin, ultimately deriving from the Latin ingenium (c. 1250), meaning "innate quality, especially mental power, hence a clever invention."

Later, as the design of civilian structures, such as bridges and buildings, matured as a technical discipline, the term civil engineering entered the lexicon as a way to distinguish between those specializing in the construction of such non-military projects and those involved in the discipline of military engineering. Ancient era

Te Ancient Romans built aqueducts to bring a steady supply of clean and fresh water to cities and towns in the empire. Te pyramids in Egypt, the Acropolis and the Parthenon in Greece, the Roman aqueducts, Via Appia and the Colosseum, Teotihuacán, the Great Wall of China, the Brihadeeswarar Temple of Tanjavur, among many others, stand as a testament to the ingenuity and skill of ancient civil and military engineers. Other monuments, no longer standing, such as the Hanging Gardens of Babylon, and the Pharos of Alexandria were important engineering achievements of their time and were considered among the Seven Wonders of the Ancient World.

Te earliest civil engineer known by name is Imhotep. As one of the oﬃcials of the Pharaoh, Djosèr, he probably designed and supervised the construction of the Pyramid of Djoser (the Step Pyramid) at Saqqara in Egypt around 2630–2611 BC. Ancient Greece developed machines in both civilian and military domains. Te Antikythera mechanism, the frst known mechanical computer, and the mechanical inventions of Archimedes are examples of early mechanical engineering. Some of Archimedes' inventions as well as the Antikythera mechanism required sophisticated knowledge of diﬀerential gearing or epicyclic gearing, two key principles in machine theory that helped design the gear trains of the Industrial Revolution, and are still widely used today in diverse felds such as robotics and automotive engineering.

Ancient Chinese, Greek, Roman and Hungarian armies employed military machines and inventions such as artillery which was developed by the Greeks around the 4th century B.C., the trireme, the ballista and the catapult. In the Middle Ages, the trebuchet was developed.

Te frst steam engine was built in 1698 by Tomas Savery. Te development of this device gave rise to the Industrial Revolution in the coming decades, allowing for the beginnings of mass production.

With the rise of engineering as a profession in the 18th century, the term became more narrowly applied to felds in which mathematics and science were applied to these ends. Similarly, in addition to military and civil engineering, the felds then known as the mechanic arts became incorporated into engineering.

Te International Space Station represents a modern engineering challenge for many disciplines. Te inventions of Tomas Newcomen and James Watt gave rise to modern mechanical engineering. Te development of specialized machines and machine tools during the industrial revolution led to the rapid growth of mechanical engineering both in its birthplace Britain and abroad.

Structural engineers working on NASA's Mars-bound spacecraft, the Phoenix Mars Lander John Smeaton was the frst self-proclaimed civil engineer and is often regarded as the "father" of civil engineering. He was an 392 English civil engineer responsible for the design of bridges, canals, harbours, and lighthouses. He was also a capable mechanical engineer and an eminent physicist. Smeaton designed the third Eddystone Lighthouse (1755–59) where he pioneered the use of 'hydraulic lime' (a form of mortar which will set under water) and developed a technique involving dovetailed blocks of granite in the building of the lighthouse. His lighthouse remained in use until 1877 and was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeaton's Tower. He is important in the history, rediscovery of, and development of modern cement, because he identifed the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to the invention of Portland cement.

Te United States census of 1850 listed the occupation of "engineer" for the frst time with a count of 2,000. Tere were fewer than 50 engineering graduates in the U.S. before 1865. In 1870 there were a dozen U.S. mechanical engineering graduates, with that number increasing to 43 per year in 1875. In 1890, there were 6,000 engineers in civil, mining, mechanical and electrical.

Tere was no chair of applied mechanism and applied mechanics at Cambridge until 1875, and no chair of engineering at Oxford until 1907. Germany established technical universities earlier.

Te foundations of electrical engineering in the 1800s included the experiments of Alessandro Volta, Michael Faraday, Georg Ohm and others and the invention of the electric telegraph in 1816 and the electric motor in 1872. Te theoretical work of James Maxwell (see: Maxwell's equations) and Heinrich Hertz in the late 19th century gave rise to the feld of electronics. Te later inventions of the vacuum tube and the transistor further accelerated the development of electronics to such an extent that electrical and electronics engineers currently outnumber their colleagues of any other engineering specialty. Chemical engineering developed in the late nineteenth century. Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants. Te role of the chemical engineer was the design of these chemical plants and processes.

Aeronautical engineering deals with aircraft design process design while aerospace engineering is a more modern term that expands the reach of the discipline by including spacecraft design. Its origins can be traced back to the aviation pioneers around the start of the 20th century although the work of Sir George Cayley has recently been dated as being from the last decade of the 18th century. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering.

Te frst PhD in engineering (technically, applied science and engineering) awarded in the United States went to Josiah Willard Gibbs at Yale University in 1863; it was also the second PhD awarded in science in the U.S.

Only a decade after the successful fights by the Wright brothers, there was extensive development of aeronautical engineering through development of military aircraft that were used in World War I. Meanwhile, research to provide fundamental background science continued by combining theoretical physics with experiments.

Engineering is a broad discipline which is often broken down into several sub-disciplines. Although an engineer will usually be trained in a specifc discipline, he or she may become multi-disciplined through experience. Engineering is often characterized as having four main branches: chemical engineering, civil engineering, electrical engineering, and mechanical engineering.

Chemical engineering is the application of physics, chemistry, biology, and engineering principles in order to carry out chemical processes on a commercial scale, such as petroleum refning, microfabrication, fermentation, and biomolecule production.

Civil engineering is the design and construction of public and private works, such as infrastructure (airports, roads, railways, water supply, and treatment etc.), bridges, tunnels, dams, and buildings. Civil engineering is traditionally broken into a number of sub-disciplines, including structural engineering, environmental engineering, and surveying. It is traditionally considered to be separate from military engineering.

Electrical engineering is the design, study, and manufacture of various electrical and electronic systems, such as Broadcast engineering, electrical circuits, generators, motors, electromagnetic/electromechanical devices, electronic devices, electronic circuits, optical fbers, optoelectronic devices, computer systems, telecommunications, instrumentation, controls, and electronics.

393 Mechanical engineering is the design and manufacture of physical or mechanical systems, such as power and energy systems, aerospace/aircraft products, weapon systems, transportation products, engines, compressors, powertrains, kinematic chains, vacuum technology, vibration isolation equipment, manufacturing, and mechatronics.

Beyond these "Big Four", a number of other branches are recognized, though many can be thought of as sub-disciplines of the four major branches, or as cross- curricular disciplines among multiple. Historically, naval engineering and mining engineering were major branches. Other engineering felds sometimes included as major branches are manufacturing engineering, acoustical engineering, corrosion engineering, instrumentation and control, aerospace, automotive, computer, electronic, petroleum, environmental, systems, audio, software, architectural, agricultural, biosystems, biomedical, geological, textile, industrial, materials, and nuclear engineering.

New specialties sometimes combine with the traditional felds and form new branches – for example, Earth systems engineering and management involves a wide range of subject areas including engineering studies, environmental science, engineering ethics and philosophy of engineering.

One who practices engineering is called an engineer, and those licensed to do so may have more formal designations such as Professional Engineer, Chartered Engineer, Incorporated Engineer, Ingenieur, European Engineer, or Designated Engineering Representative.

In the engineering design process, engineers apply mathematics and sciences such as physics to fnd novel solutions to problems or to improve existing solutions. More than ever, engineers are now required to have a profcient knowledge of relevant sciences for their design projects. As a result, many engineers continue to learn new material throughout their career.

If multiple solutions exist, engineers weigh each design choice based on their merit and choose the solution that best matches the requirements. Te crucial and unique task of the engineer is to identify, understand, and interpret the constraints on a design in order to yield a successful result. It is generally insuﬃcient to build a technically successful product, rather, it must also meet further requirements.

Constraints may include available resources, physical, imaginative or technical limitations, fexibility for future modifcations and additions, and other factors, such as requirements for cost, safety, marketability, productivity, and serviceability. By understanding the constraints, engineers derive specifcations for the limits within which a viable object or system may be produced and operated.

A general methodology and epistemology of engineering can be inferred from the historical case studies and comments provided by Walter Vincenti. Tough Vincenti's case studies are from the domain of aeronautical engineering, his conclusions can be transferred into many other branches of engineering, too.

According to Billy Vaughn Koen, the "engineering method is the use of heuristics to cause the best change in a poorly understood situation within the available resources." Koen argues that the defnition of what makes one an engineer should not be based on what he produces, but rather how he goes about it.

A drawing for a booster engine for steam locomotives. Engineering is applied to design, with emphasis on function and the utilization of mathematics and science. Engineers use their knowledge of science, mathematics, logic, economics, and appropriate experience or tacit knowledge to fnd suitable solutions to a problem. Creating an appropriate mathematical model of a problem often allows them to analyze it (sometimes defnitively), and to test potential solutions.

Usually, multiple reasonable solutions exist, so engineers must evaluate the diﬀerent design choices on their merits and choose the solution that best meets their requirements. Genrich Altshuller, after gathering statistics on a large number of patents, suggested that compromises are at the heart of "low-level" engineering designs, while at a higher level the best design is one which eliminates the core contradiction causing the problem.

Engineers typically attempt to predict how well their designs will perform to their specifcations prior to full-scale production. Tey use, among other things: prototypes, scale models, simulations, destructive tests, nondestructive tests, and stress tests. Testing ensures that products will perform as expected.

Engineers take on the responsibility of producing designs that will perform as well as expected and will not cause unintended harm to the public at large. Engineers typically include a factor of safety in their designs to reduce the risk of unexpected failure. However, the greater the safety factor, the less eﬃcient the design may be.

394 Te study of failed products is known as forensic engineering and can help the product designer in evaluating his or her design in the light of real conditions. Te discipline is of greatest value after disasters, such as bridge collapses, when careful analysis is needed to establish the cause or causes of the failure.

A computer simulation of high velocity air fow around a Space Shuttle orbiter during re-entry. Solutions to the fow require modelling of the combined eﬀects of fuid fow and the heat equations. As with all modern scientifc and technological endeavors, computers and software play an increasingly important role. As well as the typical business application software there are a number of computer aided applications (computer-aided technologies) specifcally for engineering. Computers can be used to generate models of fundamental physical processes, which can be solved using numerical methods. One of the most widely used design tools in the profession is computer-aided design (CAD) Tese allow products and components to be checked for faws; assess ft and assembly; study ergonomics; and to analyze static and dynamic characteristics of systems such as stresses, temperatures, electromagnetic emissions, electrical currents and voltages, digital logic levels, fuid fows, and kinematics. Access and distribution of all this information is generally organized with the use of product data management software.

Te engineering profession engages in a wide range of activities, from large collaboration at the societal level, and also smaller individual projects. Almost all engineering projects are obligated to some sort of fnancing agency: a company, a set of investors, or a government. Te few types of engineering that are minimally constrained by such issues are pro bono engineering and open-design engineering.

By its very nature engineering has interconnections with society, culture and human behavior. Every product or construction used by modern society is infuenced by engineering. Te results of engineering activity infuence changes to the environment, society and economies, and its application brings with it a responsibility and public safety.

Engineering projects can be subject to controversy. Examples from diﬀerent engineering disciplines include the development of nuclear weapons, the Tree Gorges Dam, the design and use of sport utility vehicles and the extraction of oil. In response, some western engineering companies have enacted serious corporate and social responsibility policies.

Engineering is a key driver of innovation and human development. Sub-Saharan Africa, in particular, has a very small engineering capacity which results in many African nations being unable to develop crucial infrastructure without outside aid. Te attainment of many of the Millennium Development Goals requires the achievement of suﬃcient engineering capacity to develop infrastructure and sustainable technological development.

All overseas development and relief NGOs make considerable use of engineers to apply solutions in disaster and development scenarios. A number of charitable organizations aim to use engineering directly for the good of mankind Engineering companies in many established economies are facing signifcant challenges with regard to the number of professional engineers being trained, compared with the number retiring. Tis problem is very prominent in the UK where engineering has a poor image and low status.[33] Tere are many negative economic and political issues that this can cause, as well as ethical issues. It is widely agreed that the engineering profession faces an "image crisis",[35] rather than it being fundamentally an unattractive career. Much work is needed to avoid huge problems in the UK and other western economies.

Many engineering societies have established codes of practice and codes of ethics to guide members and inform the public at large. Te National Society of Professional Engineers code of ethics states:

Engineering is an important and learned profession. As members of this profession, engineers are expected to exhibit the highest standards of honesty and integrity. Engineering has a direct and vital impact on the quality of life for all people. Accordingly, the services provided by engineers require honesty, impartiality, fairness, and equity, and must be dedicated to the protection of the public health, safety, and welfare. Engineers must perform under a standard of professional behavior that requires adherence to the highest principles of ethical conduct.

Tere exists an overlap between the sciences and engineering practice; in engineering, one applies science. Both areas of endeavor rely on accurate observation of materials and phenomena. Both use mathematics and classifcation criteria to analyze and communicate observations.

Scientists may also have to complete engineering tasks, such as designing experimental apparatus or building prototypes. Conversely, in the process of developing technology engineers sometimes fnd themselves exploring new phenomena, thus becoming, for the moment, scientists or more precisely "engineering scientists".

395 In the book What Engineers Know and How Tey Know It, Walter Vincenti asserts that engineering research has a character diﬀerent from that of scientifc research. First, it often deals with areas in which the basic physics or chemistry are well understood, but the problems themselves are too complex to solve in an exact manner.

Tere is a "real and important" difference between engineering and physics as similar to any science feld has to do with technology. Physics is an exploratory science that seeks knowledge of principles while Engineering uses knowledge for practical applications of principles. Te former equates an understanding into a mathematical principle while the latter measures variables involved and creates technology. For technology, physics is an auxiliary and in a way technology is considered as applied physics. Tough physics and engineering are interrelated, it does not mean that a physicist is trained to do an engineer's job. A physicist would typically require additional and relevant training. Physicists and engineers engage in different lines of work. But PhD physicists who specialize in sectors of technology and applied science are titled as Technology officer, R&D Engineers and System Engineers.

An example of this is the use of numerical approximations to the Navier–Stokes equations to describe aerodynamic fow over an aircraft, or the use of Miner's rule to calculate fatigue damage. Second, engineering research employs many semi- empirical methods that are foreign to pure scientifc research, one example being the method of parameter variation.

Engineering is quite diﬀerent from science. Scientists try to understand nature. Engineers try to make things that do not exist in nature. Engineers stress innovation and invention. To embody an invention the engineer must put his idea in concrete terms, and design something that people can use. Tat something can be a complex system, device, a gadget, a material, a method, a computing program, an innovative experiment, a new solution to a problem, or an improvement on what already exists. Since a design has to be realistic and functional, it must have its geometry, dimensions, and characteristics data defned. In the past engineers working on new designs found that they did not have all the required information to make design decisions. Most often, they were limited by insuﬃcient scientifc knowledge. Tus they studied mathematics, physics, chemistry, biology and mechanics. Often they had to add to the sciences relevant to their profession. Tus engineering sciences were born.

Although engineering solutions make use of scientifc principles, engineers must also take into account safety, eﬃciency, economy, reliability, and constructability or ease of fabrication as well as the environment, ethical and legal considerations such as patent infringement or liability in the case of failure of the solution.

Leonardo da Vinci, seen here in a self-portrait, has been described as the epitome of the artist/engineer. He is also known for his studies on human anatomy and physiology. Te study of the human body, albeit from diﬀerent directions and for diﬀerent purposes, is an important common link between medicine and some engineering disciplines. Medicine aims to sustain, repair, enhance and even replace functions of the human body, if necessary, through the use of technology.

Genetically engineered mice expressing green fuorescent protein, which glows green under blue light. Te central mouse is wild-type. Modern medicine can replace several of the body's functions through the use of artifcial organs and can signifcantly alter the function of the human body through artifcial devices such as, for example, brain implants and pacemakers. Te felds of bionics and medical bionics are dedicated to the study of synthetic implants pertaining to natural systems.

Conversely, some engineering disciplines view the human body as a biological machine worth studying and are dedicated to emulating many of its functions by replacing biology with technology. Tis has led to felds such as artifcial intelligence, neural networks, fuzzy logic, and robotics. Tere are also substantial interdisciplinary interactions between engineering and medicine.

Both felds provide solutions to real world problems. Tis often requires moving forward before phenomena are completely understood in a more rigorous scientifc sense and therefore experimentation and empirical knowledge is an integral part of both.

Medicine, in part, studies the function of the human body. Te human body, as a biological machine, has many functions that can be modeled using engineering methods.

Te heart for example functions much like a pump, the skeleton is like a linked structure with levers, the brain produces electrical signals etc. Tese similarities as well as the increasing importance and application of engineering principles in medicine, led to the development of the feld of biomedical engineering that uses concepts developed in both disciplines.

396 Newly emerging branches of science, such as systems biology, are adapting analytical tools traditionally used for engineering, such as systems modeling and computational analysis, to the description of biological systems.

Tere are connections between engineering and art, for example, architecture, landscape architecture and industrial design (even to the extent that these disciplines may sometimes be included in a university's Faculty of Engineering).

Among famous historical fgures, Leonardo da Vinci is a well-known Renaissance artist and engineer, and a prime example of the nexus between art and engineering.

A building, or edifce, is a structure with a roof and[1] walls standing more or less permanently in one place, such as a house or factory.[1] Buildings come in a variety of sizes, shapes, and functions, and have been adapted throughout history for a wide number of factors, from building materials available, to weather conditions, land prices, ground conditions, specifc uses, and aesthetic reasons. To better understand the term building compare the list of nonbuilding structures.

Buildings serve several societal needs – primarily as shelter from weather, security, living space, privacy, to store belongings, and to comfortably live and work. A building as a shelter represents a physical division of the human habitat (a place of comfort and safety) and the outside (a place that at times may be harsh and harmful).

Ever since the frst cave paintings, buildings have also become objects or canvasses of much artistic expression. In recent years, interest in sustainable planning and building practices has also become an intentional part of the design process of many new buildings.

Construction is the process of constructing a building or infrastructure.[1] Construction diﬀers from manufacturing in that manufacturing typically involves mass production of similar items without a designated purchaser, while construction typically takes place on location for a known client.[2] Construction as an industry comprises six to nine percent of the gross domestic product of developed countries.[3] Construction starts with planning, design, and fnancing; it continues until the project is built and ready for use.

Large-scale construction requires collaboration across multiple disciplines. A project manager normally manages the job, and a construction manager, design engineer, construction engineer or architect supervises it. Tose involved with the design and execution must consider zoning requirements, environmental impact of the job, scheduling, budgeting, construction-site safety, availability and transportation of building materials, logistics, inconvenience to the public caused by construction delays and bidding. Large construction projects are sometimes referred to as megaprojects.

397 17) Sound and Music

Sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid. But is usually passed through the air from source too ears.

In human physiology and psychology, sound is the reception of such waves and their perception by the brain.[1] Humans can only hear sound waves as distinct pitches when the frequency lies between about 20 Hz and 20 kHz. Sound waves above 20 kHz are known as ultrasound and is not perceptible by humans. Sound waves below 20 Hz are known as infrasound. Diﬀerent animal species have varying hearing ranges.

Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the feld of acoustics is an acoustician, while someone working in the feld of acoustical engineering may be called an acoustical engineer.[2] An audio engineer, on the other hand, is concerned with the recording, manipulation, mixing, and reproduction of sound.

Aeroacoustics is a branch of acoustics that studies noise generation via either turbulent fuid motion or aerodynamic forces interacting with surfaces. Noise generation can also be associated with periodically varying fows. A notable example of this phenomenon is the Aeolian tones produced by wind blowing over fxed objects.

Although no complete scientifc theory of the generation of noise by aerodynamic fows has been established, most practical aeroacoustic analysis relies upon the so-called aeroacoustic analogy,[1] proposed by Sir James Lighthill in the 1950s while at the University of Manchester.[2][3] whereby the governing equations of motion of the fuid are coerced into a form reminiscent of the wave equation of "classical" (i.e. linear) acoustics in the left-hand side with the remaining terms as sources in the right-hand side.

Aeolian sound or Aeolian tone is sound that is produced by wind when it passes over or through objects; Historically, Aeolus was the Greek ruler of the winds, and the Ancient Greeks believed these sounds were the voice of Aeolus. Te earliest known observations about Aeolian sounds from a "scientifc" viewpoint were made by Athanasius Kircher in 1650. An Aeolian tone is produced when air passes over an obstacle, resulting in trailing vortices with oscillatory behavior. Tese eddies can have strong periodic components, resulting in a steady tone. Tis phenomenon is the main topic of aeroacoustics; For air moving over a cylinder, empirical data shows that an Aeolian tone will be produced with the frequency where v is the air velocity, d is the diameter of the cylinder, and α is the Strouhal number, which has a value of about 0.2.

Audio signal processing is a subfeld of signal processing that is concerned with the electronic manipulation of audio signals. As audio signals may be represented in either digital or analog format, processing may occur in either domain. Analog processors operate directly on the electrical signal, while digital processors operate mathematically on the digital representation of that signal. Audio signals are electronic representations of sound waves—longitudinal waves which travel through air, consisting of compressions and rarefactions. Te energy contained in audio signals is typically measured in decibels. Audio processing was necessary for early radio broadcasting, as there were many problems with studio-to- transmitter links. Analog indicates something that is mathematically represented by a continuous function. Tus, an analog signal is one represented by a continuous stream of data, in this case along an electrical circuit in the form of voltage or current. Analog signal processing then involves physically altering the continuous signal by changing the voltage or current or charge via various electrical means.

Historically, before the advent of widespread digital technology, analog was the only method by which to manipulate a signal. Since that time, as computers and software have become more capable and aﬀordable and digital signal processing has become the method of choice. A digital representation expresses the audio waveform as a sequence of symbols, usually binary numbers. Tis permits signal processing using digital circuits such as digital signal processors, microprocessors and general- purpose computers. Most modern audio systems use a digital approach as the techniques of digital signal processing are much more powerful and eﬃcient than analog domain signal processing 398 Architectural acoustics (also known as room acoustics and building acoustics) is the science and engineering of achieving a good sound within a building and is a branch of acoustical engineering.[1] Te frst application of modern scientifc methods to architectural acoustics was carried out by Wallace Sabine in the Fogg Museum lecture room who then applied his new found knowledge to the design of Symphony Hall, Boston.[2]

Architectural acoustics can be about achieving good speech intelligibility in a theatre, restaurant or railway station, enhancing the quality of music in a concert hall or recording studio, or suppressing noise to make oﬃces and homes more productive and pleasant places to work and live in.[3] Architectural acoustic design is usually done by acoustic consultants. [4]

Bioacoustics is a cross-disciplinary science that combines biology and acoustics. Usually it refers to the investigation of sound production, dispersion and reception in animals (including humans).[1] Tis involves neurophysiological and anatomical basis of sound production and detection, and relation of acoustic signals to the medium they disperse through. Te fndings provide clues about the evolution of acoustic mechanisms, and from that, the evolution of animals that employ them.

In underwater acoustics and fsheries acoustics the term is also used to mean the eﬀect of plants and animals on sound propagated underwater, usually in reference to the use of sonar technology for biomass estimation.[2][3] Te study of substrate-borne vibrations used by animals is considered by some a distinct feld called biotremology.

Noise is frequently described as 'unwanted sound', and, within this context, environmental noise is generally present in some form in all areas of human, animal, or environmental activity. Te eﬀects in humans of exposure to environmental noise may vary from emotional to physiological and psychological.[2]

Noise at low levels is not necessarily harmful; environmental noise can also convey a sense of liveliness in an area, and is not then always considered 'unwanted'. However, the adverse eﬀects of noise exposure (i.e. noise pollution) could include: interference with speech or other 'desired' sounds, annoyance, sleep disturbance, anxiety, hearing damage and stress-related cardiovascular health problems.[3]

As a result, environmental noise is studied, regulated and monitored by many governments and institutions. Tis creates a number of diﬀerent occupations. Te basis of all decisions is supported by the objective and accurate measurement of noise. Noise is measured in decibels (dB) using a pattern-approved sound level meter. Te measurements are typically taken over a period of weeks, in all weather conditions.

Psychoacoustics is the scientifc study of sound perception and audiology – how humans perceive various sounds. More specifcally, it is the branch of science studying the psychological and physiological responses associated with sound (including noise, speech and music). It can be further categorized as a branch of psychophysics. Psychoacoustics received its name from a feld within psychology—i.e., recognition science—which deals with all kinds of human perceptions. It is an interdisciplinary feld of many areas, including psychology, acoustics, electronic engineering, physics, biology, physiology, and computer science.[1]

Audiology (from Latin audīre, "to hear"; and from Greek -λογία, -logia) is a branch of science that studies hearing, balance, and related disorders.[1] Its practitioners, who treat those with hearing loss and proactively prevent related damage, are audiologists. By employing various testing strategies (e.g. behavioral hearing tests, otoacoustic emission measurements, and electrophysiologic tests), audiologists aim to determine whether someone has normal sensitivity to sounds. If hearing loss is identifed, audiologists determine which portions of hearing (high, middle, or low frequencies) are aﬀected, to what degree (severity of loss), and where the lesion causing the hearing loss is found (outer ear, middle ear, inner ear, auditory nerve and/or central nervous system). If an audiologist determines that a hearing loss or vestibular abnormality is present he or she will provide recommendations for interventions or rehabilitation (e.g. hearing aids, cochlear implants, appropriate medical referrals).

In addition to diagnosing audiologic and vestibular pathologies, audiologists can also specialize in rehabilitation of tinnitus, hyperacusis, misophonia, auditory processing disorders, cochlear implant use and/or hearing aid use. Audiologists can provide hearing health care from birth to end-of-life.

Speech is human vocal communication using language. Each language uses phonetic combinations of a limited set of perfectly articulated and individualized vowel and consonant sounds that form the sound of its words (that is, all English words sound diﬀerent from all French words, even if they are the same word, e.g., "role" or "hotel"), and using those words in their semantic character as words in the lexicon of a language according to the syntactic constraints that govern lexical words' function in a sentence. In speaking, speakers perform many diﬀerent intentional speech acts, e.g., informing, 399 declaring, asking, persuading, directing, and can use enunciation, intonation, degrees of loudness, tempo, and other non- representational or paralinguistic aspects of vocalization to convey meaning. In their speech speakers also unintentionally communicate many aspects of their social position such as sex, age, place of origin (through accent), physical states (alertness and sleepiness, vigor or weakness, health or illness), psychic states (emotions or moods), physico-psychic states (sobriety or drunkenness, normal consciousness and trance states), education or experience, and the like.

Although people ordinarily use speech in dealing with other persons (or animals), when people swear they do not always mean to communicate anything to anyone, and sometimes in expressing urgent emotions or desires they use speech as a quasi-magical cause, as when they encourage a player in a game to do or warn them not to do something. Tere are also many situations in which people engage in solitary speech. People talk to themselves sometimes in acts that are a development of what some psychologists (e.g., Lev Vygotsky) have maintained is the use in thinking of silent speech in an interior monologue to vivify and organize cognition, sometimes in the momentary adoption of a dual persona as self addressing self as though addressing another person. Solo speech can be used to memorize or to test one's memorization of things, and in prayer or in meditation (e.g., the use of a mantra).

Researchers study many different aspects of speech: speech production and speech perception of the sounds used in a language, speech repetition, speech errors, the ability to map heard spoken words onto the vocalizations needed to recreate them, which plays a key role in children's enlargement of their vocabulary, and what different areas of the human brain, such as Broca's area and Wernicke's area, underlie speech. Speech is the subject of study for linguistics, cognitive science, communication studies, psychology, computer science, speech pathology, otolaryngology, and acoustics. Speech compares with written language,[1] which may differ in its vocabulary, syntax, and phonetics from the spoken language, a situation called diglossia.

Te evolutionary origins of speech are unknown and subject to much debate and speculation. While animals also communicate using vocalizations, and trained apes such as Washoe and Kanzi can use simple sign language, no animals' vocalizations are articulated phonemically and syntactically, and do not constitute speech.

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not diﬀerent from "normal" (audible) sound in its physical properties, except that humans cannot hear it. Tis limit varies from person to person and is approximately 20 kilohertz (20,000 hertz) in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.

Ultrasound is used in many diﬀerent felds. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible faws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles.[1] Scientists are also studying ultrasound using graphene diaphragms as a method of communication.

Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be suﬃciently high. Te ear is the primary organ for sensing infrasound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.

Te study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down to 0.1 Hz and rarely to 0.001 Hz. People use this frequency range for monitoring earthquakes, charting rock and petroleum formations below the earth, and also in ballistocardiography and seismocardiography to study the mechanics of the heart.

Infrasound is characterized by an ability to get around obstacles with little dissipation. In music, acoustic waveguide methods, such as a large pipe organ or, for reproduction, exotic loudspeaker designs such as transmission line, rotary woofer, or traditional subwoofer designs can produce low-frequency sounds, including near-infrasound. Subwoofers designed to produce infrasound are capable of sound reproduction an octave or more below that of most commercially available subwoofers, and are often about 10 times the size.

Underwater acoustics is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries. Te water may be in the ocean, a lake, a river or a tank. Typical frequencies associated with underwater acoustics are between 10 Hz and 1 MHz. Te propagation of sound in the ocean at frequencies lower than 10 Hz is usually not possible without penetrating deep into the seabed, whereas frequencies above 1 MHz are rarely used because they are absorbed very quickly. Underwater acoustics is sometimes known as hydroacoustics. Hydroacoustics is the study and application of sound in water. Hydroacoustics, using sonar technology, is most commonly used for monitoring of underwater physical and biological characteristics. Hydroacoustics can be used to

400 detect the depth of a water body (bathymetry), as well as the presence or absence, abundance, distribution, size, and behavior of underwater plants[1] and animals. Hydroacoustic sensing involves "passive acoustics" (listening for sounds) or active acoustics making a sound and listening for the echo, hence the common name for the device, echo sounder or echosounder.

Sound is defned as "(a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sensation evoked by the oscillation described in (a)."[4] Sound can be viewed as a wave motion in air or other elastic media. In this case, sound is a stimulus. Sound can also be viewed as an excitation of the hearing mechanism that results in the perception of sound. In this case, sound is a sensation.

Te behavior of sound propagation is generally aﬀected by three things:

Te viscosity of the medium. Medium viscosity determines the rate at which sound is attenuated. For many media, such as air or water, attenuation due to viscosity is negligible.When sound is moving through a medium that does not have constant physical properties, it may be refracted (either dispersed or focused).

Spherical compression (longitudinal) waves.Te mechanical vibrations that can be interpreted as sound can travel through all forms of matter: gases, liquids, solids, and plasmas. Te matter that supports the sound is called the medium. Sound cannot travel through a vacuum.

In order to understand the sound more fully, a complex wave such as the one shown in a blue background on the right of this text, is usually separated into its component parts, which are a combination of various sound wave frequencies (and noise).[9][10][11]

Sound waves are often simplifed to a description in terms of sinusoidal plane waves, which are characterized by these generic properties:

Frequency, or its inverse, wavelength; Amplitude, sound pressure or Intensity; Speed of sound; Direction; Sound that is perceptible by humans has frequencies from about 20 Hz to 20,000 Hz. In air at standard temperature and pressure, the corresponding wavelengths of sound waves range from 17 m to 17 mm. Sometimes speed and direction are combined as a velocity vector; wave number and direction are combined as a wave vector.

Transverse waves, also known as shear waves, have the additional property, polarization, and are not a characteristic of sound waves.

401 Tis was later proven wrong when found to incorrectly derive the speed. Te French mathematician Laplace corrected the formula by deducing that the phenomenon of sound travelling is not isothermal, as believed by Newton, but adiabatic. He added another factor to the equation—gamma—and multiplied. Since, the fnal equation came up to be, which is also known as the Newton–Laplace equation. In this equation, K is the elastic bulk modulus, c is the velocity of sound, and \rho is the density. Tus, the speed of sound is proportional to the square root of the ratio of the bulk modulus of the medium to its density.

Tose physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph) using the formula v[m/s] = 331 + 0.6T [°C]. In fresh water, also at 20 °C, the speed of sound is approximately 1,482 m/s (5,335 km/h; 3,315 mph). In steel, the speed of sound is about 5,960 m/s (21,460 km/h; 13,330 mph). Te speed of sound is also slightly sensitive, being subject to a second-order anharmonic eﬀect, to the sound amplitude, which means there are non-linear propagation eﬀects, such as the production of harmonics and mixed tones not present in the original sound (see parametric array).

If relativistic eﬀects are important, the speed of sound is calculated from the relativistic Euler equations.

A distinct use of the term sound from its use in physics is that in physiology and psychology, where the term refers to the subject of perception by the brain. Te feld of psychoacoustics is dedicated to such studies. Webster's 1936 dictionary defned sound as: "1. Te sensation of hearing, that which is heard; specif.: a. Psychophysics. Sensation due to stimulation of the auditory nerves and auditory centers of the brain, usually by vibrations transmitted in a material medium, commonly air, aﬀecting the organ of hearing. b. Physics. Vibrational energy which occasions such a sensation. Sound is propagated by progressive longitudinal vibratory disturbances (sound waves)." [13] Tis means that the correct response to the question: "if a tree falls in the forest with no one to hear it fall, does it make a sound?" is "yes", and "no", dependent on whether being answered using the physical, or the psychophysical defnition, respectively.

Te physical reception of sound in any hearing organism is limited to a range of frequencies. Humans normally hear sound frequencies between approximately 20 Hz and 20,000 Hz (20 kHz),[14]:382 Te upper limit decreases with age.[14]:249 Sometimes sound refers to only those vibrations with frequencies that are within the hearing range for humans[15] or sometimes it relates to a particular animal. Other species have diﬀerent ranges of hearing. For example, dogs can perceive vibrations higher than 20 kHz.

As a signal perceived by one of the major senses, sound is used by many species for detecting danger, navigation, predation, and communication. Earth's atmosphere, water, and virtually any physical phenomenon, such as fre, rain, wind, surf, or earthquake, produces (and is characterized by) its unique sounds. Many species, such as frogs, birds, marine and terrestrial mammals, have also developed special organs to produce sound. In some species, these produce song and speech. Furthermore, humans have developed culture and technology (such as music, telephone and radio) that allows them to generate, record, transmit, and broadcast sound.

Noise is a term often used to refer to an unwanted sound. In science and engineering, noise is an undesirable component that obscures a wanted signal. However, in sound perception it can often be used to identify the source of a sound and is an important component of timbre perception (see above).

Soundscape is the component of the acoustic environment that can be perceived by humans. Te acoustic environment is the combination of all sounds (whether audible to humans or not) within a given area as modifed by the environment and understood by people, in context of the surrounding environment.

Tere are, historically, six experimentally separable ways in which sound waves are analysed. Tey are: pitch, duration, loudness, timbre, sonic texture and spatial location.[16] Some of these terms have a standardised defnition (for instance in the ANSI Acoustical Terminology ANSI/ASA S1.1-2013). More recent approaches have also considered temporal envelope and temporal fne structure as perceptually relevant analyses.

Pitch is perceived as how "low" or "high" a sound is and represents the cyclic, repetitive nature of the vibrations that make up sound. For simple sounds, pitch relates to the frequency of the slowest vibration in the sound (called the fundamental harmonic). In the case of complex sounds, pitch perception can vary. Sometimes individuals identify diﬀerent pitches for the same sound, based on their personal experience of particular sound patterns. Selection of a particular pitch is determined by pre-conscious examination of vibrations, including their frequencies and the balance between them. Specifc attention is given to recognising potential harmonics.[20][21] Every sound is placed on a pitch continuum from low to high. For

402 example: white noise (random noise spread evenly across all frequencies) sounds higher in pitch than pink noise (random noise spread evenly across octaves) as white noise has more high frequency content. Figure 1 shows an example of pitch recognition. During the listening process, each sound is analysed for a repeating pattern (See Figure 1: orange arrows) and the results forwarded to the auditory cortex as a single pitch of a certain height (octave) and chroma (note name).

Duration is perceived as how "long" or "short" a sound is and relates to onset and offset signals created by nerve responses to sounds. Te duration of a sound usually lasts from the time the sound is frst noticed until the sound is identifed as having changed or ceased.[22] Sometimes this is not directly related to the physical duration of a sound. For example; in a noisy environment, gapped sounds (sounds that stop and start) can sound as if they are continuous because the offset messages are missed owing to disruptions from noises in the same general bandwidth.[23] Tis can be of great beneft in understanding distorted messages such as radio signals that suffer from interference, as (owing to this effect) the message is heard as if it was continuous. Figure 2 gives an example of duration identifcation. When a new sound is noticed (see Figure 2, Green arrows), a sound onset message is sent to the auditory cortex. When the repeating pattern is missed, a sound offset messages is sent.

Loudness is perceived as how "loud" or "soft" a sound is and relates to the totalled number of auditory nerve stimulations over short cyclic time periods, most likely over the duration of theta wave cycles. Tis means that at short durations, a very short sound can sound softer than a longer sound even though they are presented at the same intensity level. Past around 200 ms this is no longer the case and the duration of the sound no longer aﬀects the apparent loudness of the sound. Figure 3 gives an impression of how loudness information is summed over a period of about 200 ms before being sent to the auditory cortex. Louder signals create a greater 'push' on the Basilar membrane and thus stimulate more nerves, creating a stronger loudness signal. A more complex signal also creates more nerve frings and so sounds louder (for the same wave amplitude) than a simpler sound, such as a sine wave.

Timbre is perceived as the quality of different sounds (e.g. the thud of a fallen rock, the whir of a drill, the tone of a musical instrument or the quality of a voice) and represents the pre-conscious allocation of a sonic identity to a sound (e.g. “it’s an oboe!"). Tis identity is based on information gained from frequency transients, noisiness, unsteadiness, perceived pitch and the spread and intensity of overtones in the sound over an extended time frame.[9][10][11] Te way a sound changes over time (see fgure 4) provides most of the information for timbre identifcation. Even though a small section of the wave form from each instrument looks very similar (see the expanded sections indicated by the orange arrows in fgure 4), differences in changes over time between the clarinet and the piano are evident in both loudness and harmonic content. Less noticeable are the different noises heard, such as air hisses for the clarinet and hammer strikes for the piano.

Sonic texture relates to the number of sound sources and the interaction between them.[27][28] Te word 'texture', in this context, relates to the cognitive separation of auditory objects.[29] In music, texture is often referred to as the difference between unison, polyphony and homophony, but it can also relate (for example) to a busy cafe; a sound which might be referred to as 'cacophony'. However texture refers to more than this. Te texture of an orchestral piece is very different to the texture of a brass quintet because of the different numbers of players. Te texture of a market place is very different to a school hall because of the differences in the various sound sources.

Spatial location (see: Sound localization) represents the cognitive placement of a sound in an environmental context; including the placement of a sound on both the horizontal and vertical plane, the distance from the sound source and the characteristics of the sonic environment.[29][30] In a thick texture, it is possible to identify multiple sound sources using a combination of spatial location and timbre identifcation. It is the main reason why we can pick the sound of an oboe in an orchestra and the words of a single person at a cocktail party.

Sound pressure p, SPL,LPA Particle velocity v, SVL Particle displacement δ Sound intensity I, SIL Sound power P, SWL, LWA Sound energy W Sound energy density w Sound exposure E, SEL Acoustic impedance Z Speed of sound c Audio frequency AF Transmission loss TL 403 Sound pressure is the diﬀerence, in a given medium, between average local pressure and the pressure in the sound wave. A square of this diﬀerence (i.e., a square of the deviation from the equilibrium pressure) is usually averaged over time and/or space, and a square root of this average provides a root mean square (RMS) value. For example, 1 Pa RMS sound pressure (94 dBSPL) in atmospheric air implies that the actual pressure in the sound wave oscillates between and, that is between 101323.6 and 101326.4 Pa. As the human ear can detect sounds with a wide range of amplitudes, sound pressure is often measured as a level on a logarithmic decibel scale. Te sound pressure level (SPL) or Lp is defned as where p is the root-mean-square sound pressure and is a reference sound pressure. Commonly used reference sound pressures, defned in the standard ANSI S1.1-1994, are 20 µPa in air and 1 µPa in water. Without a specifed reference sound pressure, a value expressed in decibels cannot represent a sound pressure level. Since the human ear does not have a fat spectral response, sound pressures are often frequency weighted so that the measured level matches perceived levels more closely. Te International Electrotechnical Commission (IEC) has defned several weighting schemes. A-weighting attempts to match the response of the human ear to noise and A-weighted sound pressure levels are labeled dBA. C-weighting is used to measure peak levels.

Musical acoustics or music acoustics is a branch of acoustics concerned with researching and describing the physics of music – how sounds are employed to make music. Examples of areas of study are the function of musical instruments, the human voice (the physics of speech and singing), computer analysis of melody, and in the clinical use of music in music therapy.

Music is an art form and cultural activity whose medium is sound organized in time. General defnitions of music include common elements such as pitch (which governs melody and harmony), rhythm (and its associated concepts tempo, meter, and articulation), dynamics (loudness and softness), and the sonic qualities of timbre and texture (which are sometimes termed the "color" of a musical sound). Diﬀerent styles or types of music may emphasize, de-emphasize or omit some of these elements. Music is performed with a vast range of instruments and vocal techniques ranging from singing to rapping; there are solely instrumental pieces, solely vocal pieces (such as songs without instrumental accompaniment) and pieces that combine singing and instruments. Te word derives from Greek μουσική (mousike; "art of the Muses").[1] See glossary of musical terminology.

In its most general form, the activities describing music as an art form or cultural activity include the creation of works of music (songs, tunes, symphonies, and so on), the criticism of music, the study of the history of music, and the aesthetic examination of music. Ancient Greek and Indian philosophers defned music as tones ordered horizontally as melodies and vertically as harmonies. Common sayings such as "the harmony of the spheres" and "it is music to my ears" point to the notion that music is often ordered and pleasant to listen to. However, 20th-century composer John Cage thought that any sound can be music, saying, for example, "Tere is no noise, only sound."[2]

Te creation, performance, signifcance, and even the defnition of music vary according to culture and social context. Indeed, throughout history, some new forms or styles of music have been criticized as "not being music", including Beethoven's Grosse Fuge string quartet in 1825,[3] early jazz in the beginning of the 1900s[4] and hardcore punk in the 1980s.[5] Tere are many types of music, including popular music, traditional music, art music, music written for religious ceremonies and work songs such as chanteys. Music ranges from strictly organized compositions–such as Classical music symphonies from the 1700s and 1800s, through to spontaneously played improvisational music such as jazz, and avant-garde styles of chance-based contemporary music from the 20th and 21st centuries.

Music can be divided into genres (e.g., country music) and genres can be further divided into subgenres (e.g., country blues and pop country are two of the many country subgenres), although the dividing lines and relationships between music genres are often subtle, sometimes open to personal interpretation, and occasionally controversial. For example, it can be hard to draw the line between some early 1980s hard rock and heavy metal. Within the arts, music may be classifed as a performing art, a fne art or as an auditory art. Music may be played or sung and heard live at a rock concert or orchestra performance, heard live as part of a dramatic work (a music theater show or opera), or it may be recorded and listened to on a radio, MP3 player, CD player, smartphone or as flm score or TV show.

In many cultures, music is an important part of people's way of life, as it plays a key role in religious rituals, rite of passage ceremonies (e.g., graduation and marriage), social activities (e.g., dancing) and cultural activities ranging from amateur karaoke singing to playing in an amateur funk band or singing in a community choir. People may make music as a hobby, 404 like a teen playing cello in a youth orchestra, or work as a professional musician or singer. Te music industry includes the individuals who create new songs and musical pieces (such as songwriters and composers), individuals who perform music (which include orchestra, jazz band and rock band musicians, singers and conductors), individuals who record music (music producers and sound engineers), individuals who organize concert tours, and individuals who sell recordings, sheet music, and scores to customers.

Musica universalis (literally universal music), also called Music of the spheres or Harmony of the Spheres, is an ancient philosophical concept that regards proportions in the movements of celestial bodies—the Sun, Moon, and planets—as a form of musica (the Medieval Latin term for music). Tis "music" is not usually thought to be literally audible, but a harmonic, mathematical or religious concept. Te idea continued to appeal to thinkers about music until the end of the Renaissance, infuencing scholars of many kinds, including humanists. Further scientifc exploration has determined specifc proportions in some orbital motion, described as orbital resonance.

In celestial mechanics, an orbital resonance occurs when orbiting bodies exert a regular, periodic gravitational infuence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly this relationship is found for a pair of objects. Te physical principle behind orbital resonance is similar in concept to pushing a child on a swing, where the orbit and the swing both have a natural frequency, and the other body doing the "pushing" will act in periodic repetition to have a cumulative eﬀect on the motion. Orbital resonances greatly enhance the mutual gravitational infuence of the bodies, i.e., their ability to alter or constrain each other's orbits. In most cases, this results in an unstable interaction, in which the bodies exchange momentum and shift orbits until the resonance no longer exists. Under some circumstances, a resonant system can be stable and self-correcting, so that the bodies remain in resonance. Examples are the 1:2:4 resonance of Jupiter's moons Ganymede, Europa and Io, and the 2:3 resonance between Pluto and Neptune. Unstable resonances with Saturn's inner moons give rise to gaps in the rings of Saturn. Te special case of 1:1 resonance between bodies with similar orbital radii causes large Solar System bodies to eject most other bodies sharing their orbits; this is part of the much more extensive process of clearing the neighbourhood, an eﬀect that is used in the current defnition of a planet.

A binary resonance ratio in this article should be interpreted as the ratio of number of orbits completed in the same time interval, rather than as the ratio of orbital periods, which would be the inverse ratio. Tus the 2:3 ratio above means Pluto completes two orbits in the time it takes Neptune to complete three. In the case of resonance relationships among three or more bodies, either type of ratio may be used (in such cases the smallest whole-integer ratio sequences are not necessarily reversals of each other) and the type of ratio will be specifed.

"Composition" is the act or practice of creating a song, an instrumental music piece, a work with both singing and instruments, or another type of music. In many cultures, including Western classical music, the act of composing also includes the creation of music notation, such as a sheet music "score", which is then performed by the composer or by other singers or musicians. In popular music and traditional music, the act of composing, which is typically called songwriting, may involve the creation of a basic outline of the song, called the lead sheet, which sets out the melody, lyrics and chord progression. In classical music, the composer typically orchestrates his or her own compositions, but in musical theatre and in pop music, songwriters may hire an arranger to do the orchestration. In some cases, a songwriter may not use notation at all, and instead compose the song in her mind and then play or record it from memory. In jazz and popular music, notable recordings by infuential performers are given the weight that written scores play in classical music.

Even when music is notated relatively precisely, as in classical music, there are many decisions that a performer has to make, because notation does not specify all of the elements of music precisely. Te process of deciding how to perform music that has been previously composed and notated is termed "interpretation". Diﬀerent performers' interpretations of the same work of music can vary widely, in terms of the tempos that are chosen and the playing or singing style or phrasing of the melodies. Composers and songwriters who present their own music are interpreting their songs, just as much as those who perform the music of others. Te standard body of choices and techniques present at a given time and a given place is referred to as performance practice, whereas interpretation is generally used to mean the individual choices of a performer.[citation needed]

Although a musical composition often uses musical notation and has a single author, this is not always the case. A work of music can have multiple composers, which often occurs in popular music when a band collaborates to write a song, or in musical theatre, when one person writes the melodies, a second person writes the lyrics, and a third person orchestrates the songs. In some styles of music, such as the blues, a composer/songwriter may create, perform and record new songs or pieces without ever writing them down in music notation. A piece of music can also be composed with words, images, or computer programs that explain or notate how the singer or musician should create musical sounds. Examples range from avant-garde music that uses graphic notation, to text compositions such as Aus den sieben Tagen, to computer programs that select sounds for musical pieces. Music that makes heavy use of randomness and chance is called aleatoric music, and is associated

405 with contemporary composers active in the 20th century, such as John Cage, Morton Feldman, and Witold Lutosławski. A more commonly known example of chance-based music is the sound of wind chimes jingling in a breeze.

Te study of composition has traditionally been dominated by examination of methods and practice of Western classical music, but the defnition of composition is broad enough to include the creation of popular music and traditional music songs and instrumental pieces as well as spontaneously improvised works like those of free jazz performers and African percussionists such as Ewe drummers.

An instrumental is a musical composition or recording without lyrics, or singing, although it might include some inarticulate vocals, such as shouted backup vocals in a Big Band setting. Trough semantic widening, a broader sense of the word song may refer to instrumentals.[1][2][3] Te music is primarily or exclusively produced using musical instruments. An instrumental can exist in music notation, after it is written by a composer; in the mind of the composer (especially in cases where the composer himself will perform the piece, as in the case of a blues solo guitarist or a folk music fddle player); as a piece that is performed live by a single instrumentalist or a musical ensemble, which could range in components from a duo or trio to a large Big Band, concert band or orchestra.

In a song that is otherwise sung, a section that is not sung but which is played by instruments can be called an instrumental interlude, or, if it occurs at the beginning of the song, before the singer starts to sing, an instrumental introduction. If the instrumental section highlights the skill, musicality, and often the virtuosity of a particular performer (or group of performers), the section may be called a "solo" (e.g., the guitar solo that is a key section of heavy metal music and hard rock songs). If the instruments are percussion instruments, the interlude can be called a percussion interlude or "percussion break". Tese interludes are a form of break in the song.

Music notation or musical notation is any system used to visually represent aurally perceived music played with instruments or sung by the human voice through the use of written, printed, or otherwise-produced symbols.

Types and methods of notation have varied between cultures and throughout history, and much information about ancient music notation is fragmentary. Even in the same time period, such as in the 2010s, different styles of music and different cultures use different music notation methods; for example, for professional classical music performers, sheet music using staves and noteheads is the most common way of notating music, but for professional country music session musicians, the Nashville Number System is the main method.

Te symbols used include ancient symbols and modern symbols made upon any media such as symbols cut into stone, made in clay tablets, made using a pen on papyrus or parchment or manuscript paper; printed using a printing press (ca. 1400s), a computer printer (ca. 1980s) or other printing or modern copying technology.

Although many ancient cultures used symbols to represent melodies and rhythms, none of them were particularly comprehensive, and this has limited today's understanding of their music. Te seeds of what would eventually become modern western notation were sown in medieval Europe, starting with the Catholic Church's goal for ecclesiastical uniformity. Te church began notating plainchant melodies so that the same chants could be used throughout the church. Music notation developed further in the Renaissance and Baroque music eras. In the classical period (1750–1820) and the Romantic music era (1820–1900), notation continued to develop as new musical instrument technologies were developed. In the contemporary classical music of the 20th and 21st century, music notation has continued to develop, with the introduction of graphical notation by some modern composers and the use, since the 1980s, of computer-based score writer programs for notating music. Music notation has been adapted to many kinds of music, including classical music, popular music, and traditional music.

Sheet music is a handwritten or printed form of music notation that uses modern musical symbols to indicate the pitches (melodies), rhythms or chords of a song or instrumental musical piece. Like its analogs – printed books or pamphlets in English, Arabic or other languages – the medium of sheet music typically is paper (or, in earlier centuries, papyrus or parchment), although the access to musical notation since the 1980s has included the presentation of musical notation on computer screens and the development of scorewriter computer programs that can notate a song or piece electronically, and, in some cases, "play back" the notated music using a synthesizer or virtual instruments.

Use of the term "sheet" is intended to diﬀerentiate written or printed forms of music from sound recordings (on vinyl record, cassette, CD), radio or TV broadcasts or recorded live performances, which may capture flm or video footage of the performance as well as the audio component. In everyday use, "sheet music" (or simply "music") can refer to the print publication of commercial sheet music in conjunction with the release of a new flm, TV show, record album, or other special or popular event which involves music. Te frst printed sheet music made with a printing press was made in 1473.

406 Sheet music is the basic form in which Western classical music is notated so that it can be learned and performed by solo singers or instrumentalists or musical ensembles. Many forms of traditional and popular Western music are commonly learned by singers and musicians "by ear", rather than by using sheet music (although in many cases, traditional and pop music may also be available in sheet music form).

Te term score is a common alternative (and more generic) term for sheet music, and there are several types of scores, as discussed below. Te term score can also refer to theatre music, orchestral music or songs written for a play, musical, opera or ballet, or to music or songs written for a television programme or flm; for the last of these, see Film score.

A full score is a large book showing the music of all instruments or voices in a composition lined up in a fxed order. It is large enough for a conductor to be able to read while directing orchestra or opera rehearsals and performances. In addition to their practical use for conductors leading ensembles, full scores are also used by musicologists, music theorists, composers and music students who are studying a given work.

A miniature score is like a full score but much reduced in size. It is too small for use in a performance by a conductor, but handy for studying a piece of music, whether it be for a large ensemble or a solo performer. A miniature score may contain some introductory remarks.

A study score is sometimes the same size as, and often indistinguishable from, a miniature score, except in name. Some study scores are octavo size and are thus somewhere between full and miniature score sizes. A study score, especially when part of an anthology for academic study, may include extra comments about the music and markings for learning purposes.

A piano score (or piano reduction) is a more or less literal transcription for piano of a piece intended for many performing parts, especially orchestral works; this can include purely instrumental sections within large vocal works (see vocal score immediately below). Such arrangements are made for either piano solo (two hands) or piano duet (one or two pianos, four hands). Extra small staves are sometimes added at certain points in piano scores for two hands to make the presentation more complete, though it is usually impractical or impossible to include them while playing.

As with vocal score (below), it takes considerable skill to reduce an orchestral score to such smaller forms because the reduction needs to be not only playable on the keyboard but also thorough enough in its presentation of the intended harmonies, textures, fgurations, etc. Sometimes markings are included to show which instruments are playing at given points.

While piano scores are usually not meant for performance outside of study and pleasure (Franz Liszt's concert transcriptions of Beethoven's symphonies being one group of notable exceptions), ballets get the most practical beneft from piano scores because with one or two pianists they allow the ballet to do many rehearsals at a much lower cost, before an orchestra has to be hired for the fnal rehearsals. Piano scores can also be used to train beginning conductors, who can conduct a pianist playing a piano reduction of a symphony; this is much less costly than conducting a full orchestra. Piano scores of operas do not include separate staves for the vocal parts, but they may add the sung text and stage directions above the music.

A part is an extraction from the full score of a particular instrument's part. It is used by orchestral players in performance, where the full score would be too cumbersome. However, in practice, it can be a substantial document if the work is lengthy, and a particular instrument is playing for much of its duration.

A vocal score (or, more properly, piano-vocal score) is a reduction of the full score of a vocal work (e.g., opera, musical, oratorio, cantata, etc.) to show the vocal parts (solo and choral) on their staves and the orchestral parts in a piano reduction (usually for two hands) underneath the vocal parts; the purely orchestral sections of the score are also reduced for piano. If a portion of the work is a cappella, a piano reduction of the vocal parts is often added to aid in rehearsal (this often is the case with a cappella religious sheet music).

Piano-vocal scores serve as a convenient way for vocal soloists and choristers to learn the music and rehearse separately from the orchestra. Te vocal score of a musical typically does not include the spoken dialogue, except for cues. Piano-vocal scores are used to provide piano accompaniment for the performance of operas, musicals and oratorios by amateur groups and some small-scale professional groups. Tis may be done by a single piano player or by two piano players. With some 2000s- era musicals, keyboardists may play synthesizers instead of piano.

A choral score for Leonard Bernstein's Chichester Psalms. Te related but less common choral score contains the choral parts with reduced accompaniment.

407 Te comparable organ score exists as well, usually in association with church music for voices and orchestra, such as arrangements (by later hands) of Handel's Messiah. It is like the piano-vocal score in that it includes staves for the vocal parts and reduces the orchestral parts to be performed by one person. Unlike the vocal score, the organ score is sometimes intended by the arranger to substitute for the orchestra in performance if necessary.

A collection of songs from a given musical is usually printed under the label vocal selections. Tis is diﬀerent from the vocal score from the same show in that it does not present the complete music, and the piano accompaniment is usually simplifed and includes the melody line.

A short score is a reduction of a work for many instruments to just a few staves. Rather than composing directly in full score, many composers work out some type of short score while they are composing and later expand the complete orchestration. An opera, for instance, may be written frst in a short score, then in full score, then reduced to a vocal score for rehearsal. Short scores are often not published; they may be more common for some performance venues (e.g., band) than in others. Because of their preliminary nature, short scores are the principal reference point for those composers wishing to attempt a 'completion' of another's unfnished work (e.g. Movements 2 through 5 of Gustav Mahler's 10th Symphony or the third Act of Alban Berg's opera Lulu).

An open score is a score of a polyphonic piece showing each voice on a separate staff. In Renaissance or Baroque keyboard pieces, open scores of four staves were sometimes used instead of the more modern convention of one staff per hand.[1] It is also sometimes synonymous with full score (which may have more than one part per staff).

Scores from the Baroque period (1600-1750) are very often in the form of a bass line in the bass clef and the melodies played by instrument or sung on an upper stave (or staves) in the treble clef. Te bass line typically had fgures written above the bass notes indicating which intervals above the bass (e.g., chords) should be played, an approach called fgured bass. Te fgures indicate which intervals the harpsichordist, pipe organist or lute player should play above each bass note.

A lead sheet specifes only the melody, lyrics and harmony, using one staﬀ with chord symbols placed above and lyrics below. It is commonly used in popular music and in jazz to capture the essential elements of song without specifying the details of how the song should be arranged or performed.

A chord chart (or simply, chart) contains little or no melodic information at all but provides fundamental harmonic information. Some chord charts also indicate the rhythm that should be played, particularly if there is a syncopated series of "hits" that the arranger wants all of the rhythm section to perform. Otherwise, chord charts either leave the rhythm blank or indicate slashes for each beat.

Tis is the most common kind of written music used by professional session musicians playing jazz or other forms of popular music and is intended for the rhythm section (usually containing piano, guitar, bass and drums) to improvise their accompaniment and for any improvising soloists (e.g., saxophone players or trumpet players) to use as a reference point for their extemporized lines.

A fake book is a collection of jazz songs and tunes with just the basic elements of the music provided. Tere are two types of fake books: (1) collections of lead sheets, which include the melody, chords, and lyrics (if present), and (2) collections of songs and tunes with only the chords. Fake books that contain only the chords are used by rhythm section performers (notably chord-playing musicians such as electric guitarists and piano players and the bassist) to help guide their improvisation of accompaniment parts for the song. Fake books with only the chords can also be used by "lead instruments" (e.g., saxophone or trumpet) as a guide to their improvised solo performances. Since the melody is not included in chord-only fake books, lead instrument players are expected to know the melody.

A C major scale in regular notation (above) and in tabulature for guitar (below). A tablature (or tab) is a special type of musical score – most typically for a solo instrument – which shows where to play the pitches on the given instrument rather than which pitches to produce, with rhythm indicated as well. Tabulature is widely used in the 2000s for guitar and electric bass songs and pieces in popular music genres such as rock music and heavy metal music. Tis type of notation was frst used in the late Middle Ages, and it has been used for keyboard (e.g., pipe organ) and for fretted string instruments (lute, guitar).

Musical notation was developed before parchment or paper were used for writing. Te earliest form of musical notation can be found in a cuneiform tablet that was created at Nippur, in Sumer (today's Iraq) in about 2000 BC. Te tablet represents

408 fragmentary instructions for performing music, that the music was composed in harmonies of thirds, and that it was written using a diatonic scale.[2]

A tablet from about 1250 BC shows a more developed form of notation.[3] Although the interpretation of the notation system is still controversial, it is clear that the notation indicates the names of strings on a lyre, the tuning of which is described in other tablets.[4] Although they are fragmentary, these tablets represent the earliest notated melodies found anywhere in the world.[4]

Te original stone at Delphi containing the second of the two Delphic Hymns to Apollo. Te music notation is the line of occasional symbols above the main, uninterrupted line of Greek lettering. Ancient Greek musical notation was in use from at least the 6th century BC until approximately the 4th century AD; several complete compositions and fragments of compositions using this notation survive. Te notation consists of symbols placed above text syllables. An example of a complete composition is the Seikilos epitaph, which has been variously dated between the 2nd century BC to the 1st century AD.

In Ancient Greek music, three hymns by Mesomedes of Crete exist in manuscript. One of the oldest known examples of music notation is a papyrus fragment of the Hellenic era play Orestes (408 BC) has been found, which contains musical notation for a choral ode. Ancient Greek notation appears to have fallen out of use around the time of the Decline of the Roman Empire.

Rhythm (from Greek ῥυθμός, rhythmos, "any regular recurring motion, symmetry" (Liddell and Scott 1996)) generally means a "movement marked by the regulated succession of strong and weak elements, or of opposite or diﬀerent conditions" (Anon. 1971, 2537). Tis general meaning of regular recurrence or pattern in time can apply to a wide variety of cyclical natural phenomena having a periodicity or frequency of anything from microseconds to several seconds (as with the riﬀ in a rock music song); to several minutes or hours, or, at the most extreme, even over many years.

In the performance arts, rhythm is the timing of events on a human scale; of musical sounds and silences that occur over time, of the steps of a dance, or the meter of spoken language and poetry. In some performing arts, such as hip hop music, the rhythmic delivery of the lyrics is one of the most important elements of the style. Rhythm may also refer to visual presentation, as "timed movement through space" (Jirousek 1995) and a common language of pattern unites rhythm with geometry. In recent years, rhythm and meter have become an important area of research among music scholars. Recent work in these areas includes books by Maury Yeston (1976), Fred Lerdahl and Ray Jackendoﬀ (Lerdahl and Jackendoﬀ 1983), Jonathan Kramer, Christopher Hasty (1997), Godfried Toussaint (2005), William Rothstein (1989), Joel Lester (Lester 1986), and Guerino Mazzola.

Te establishment of a basic beat requires the perception of a regular sequence of distinct short-duration pulses and, as a subjective perception of loudness is relative to background noise levels, a pulse must decay to silence before the next occurs if it is to be really distinct. For this reason, the fast-transient sounds of percussion instruments lend themselves to the defnition of rhythm. Musical cultures that rely upon such instruments may develop multi-layered polyrhythm and simultaneous rhythms in more than one time signature, called polymeter. Such are the cross-rhythms of Sub-Saharan Africa and the interlocking kotekan rhythms of the gamelan.

For information on rhythm in Indian music see Tala (music). For other Asian approaches to rhythm see Rhythm in Persian music, Rhythm in Arabian music and Usul—Rhythm in Turkish music and Dumbek rhythms.

Pulse, beat and measure Further information: Pulse (music) and Beat (music)

Metric levels: beat level shown in middle with division levels above and multiple levels below. Most music, dance and oral poetry establishes and maintains an underlying "metric level", a basic unit of time that may be audible or implied, the pulse or tactus of the mensural level (Berry 1987, 349; Lerdahl and Jackendoﬀ 1983; Fitch and Rosenfeld 2007, 44), or beat level, sometimes simply called the beat. Tis consists of a (repeating) series of identical yet distinct periodic short-duration stimuli perceived as points in time (Winold 1975, 213). Te "beat" pulse is not necessarily the fastest or the slowest component of the rhythm but the one that is perceived as fundamental: it has a tempo to which listeners entrain as they tap their foot or dance to a piece of music (Handel 1989). It is currently most often designated as a crotchet or quarter note in western notation (see time signature). Faster levels are division levels, and slower levels are multiple levels (Winold 1975, 213). Maury Yeston clarifed "Rhythms of recurrence" arise from the interaction of two levels of motion, the faster providing the pulse and the slower organizing the beats into repetitive groups (Yeston 1976, 50–52). 409 "Once a metric hierarchy has been established, we, as listeners, will maintain that organization as long as minimal evidence is present" (Lester 1986, 77).

A durational pattern that synchronises with a pulse or pulses on the underlying metric level may be called a rhythmic unit. Tese may be classifed as; metric—even patterns, such as steady eighth notes or pulses—intrametric—confrming patterns, such as dotted eighth-sixteenth note and swing patterns—contrametric—non-confrming, or syncopated patterns and extrametric—irregular patterns, such as tuplets.

A rhythmic gesture is any durational pattern that, in contrast to the rhythmic unit, does not occupy a period of time equivalent to a pulse or pulses on an underlying metric level. It may be described according to its beginning and ending or by the rhythmic units it contains. Beginnings on a strong pulse are thetic, a weak pulse, anacrustic and those beginning after a rest or tied-over note are called initial rest. Endings on a strong pulse are strong, a weak pulse, weak and those that end on a strong or weak upbeat are upbeat (Winold 1975, 239).

Rhythm is marked by the regulated succession of opposite elements, the dynamics of the strong and weak beat, the played beat and the inaudible but implied rest beat, the long and short note. As well as perceiving rhythm we must be able to anticipate it. Tis depends on repetition of a pattern that is short enough to memorize.

Te alternation of the strong and weak beat is fundamental to the ancient language of poetry, dance and music. Te common poetic term "foot" refers, as in dance, to the lifting and tapping of the foot in time. In a similar way musicians speak of an upbeat and a downbeat and of the "on" and "oﬀ" beat. Tese contrasts naturally facilitate a dual hierarchy of rhythm and depend on repeating patterns of duration, accent and rest forming a "pulse-group" that corresponds to the poetic foot. Normally such pulse-groups are defned by taking the most accented beat as the frst and counting the pulses until the next accent (MacPherson 1930, 5; Scholes 1977b). A rhythm that accents another beat and de-emphasises the downbeat as established or assumed from the melody or from a preceding rhythm is called syncopated rhythm.

Normally, even the most complex of meters may be broken down into a chain of duple and triple pulses (MacPherson 1930, 5; Scholes 1977b) either by addition or division. According to Pierre Boulez, beat structures beyond four, in western music, are "simply not natural" (Slatkin n.d., at 5:05).

Te tempo of the piece is the speed or frequency of the tactus, a measure of how quickly the beat fows. Tis is often measured in 'beats per minute' (bpm): 60 bpm means a speed of one beat per second, a frequency of 1 Hz. A rhythmic unit is a durational pattern that has a period equivalent to a pulse or several pulses (Winold 1975, 237). Te duration of any such unit is inversely related to its tempo.

Musical sound may be analyzed on fve diﬀerent time scales, which Moravscik has arranged in order of increasing duration (Moravcsik 2002, 114).

Supershort: a single cycle of an audible wave, approximately 1⁄30–1⁄10,000 second (30–10,000 Hz or more than 1,800 bpm). Tese, though rhythmic in nature, are not perceived as separate events but as continuous musical pitch. Short: of the order of one second (1 Hz, 60 bpm, 10–100,000 audio cycles). Musical tempo is generally specifed in the range 40 to 240 beats per minute. A continuous pulse cannot be perceived as a musical beat if it is faster than 8–10 per second (8–10 Hz, 480–600 bpm) or slower than 1 per 1.5–2 seconds (0.6–0.5 Hz, 40–30 bpm). Too fast a beat becomes a drone, too slow a succession of sounds seems unconnected (Fraisse 1956[page needed]; Woodrow 1951[page needed], both quoted in Covaciu-Pogorilowski n.d.). Tis time-frame roughly corresponds to the human heart rate and to the duration of a single step, syllable or rhythmic gesture. Medium: ≥ few seconds, Tis median durational level "defnes rhythm in music" (Moravcsik 2002, 114) as it allows the defnition of a rhythmic unit, the arrangement of an entire sequence of accented, unaccented and silent or "rest" pulses into the cells of a measure that may give rise to the "briefest intelligible and self-existent musical unit" (Scholes 1977c), a motif or fgure. Tis may be further organized, by repetition and variation, into a defnite phrase that may characterise an entire genre of music, dance or poetry and that may be regarded as the fundamental formal unit of music (MacPherson 1930,[page needed]). Long: ≥ many seconds or a minute, corresponding to a durational unit that "consists of musical phrases" (Moravcsik 2002, 114)—which may make up a melody, a formal section, a poetic stanza or a characteristic sequence of dance moves and steps. Tus the temporal regularity of musical organisation includes the most elementary levels of musical form (MacPherson 1930, 3). Very long: ≥ minutes or many hours, musical compositions or subdivisions of compositions.

410 Curtis Roads (Roads 2001) takes a wider view by distinguishing nine-time scales, this time in order of decreasing duration. Te frst two, the infnite and the supra musical, encompass natural periodicities of months, years, decades, centuries, and greater, while the last three, the sample and subsample, which take account of digital and electronic rates "too brief to be properly recorded or perceived", measured in millionths of seconds (microseconds), and fnally the infnitesimal or infnitely brief, are again in the extra-musical domain. Roads' Macro level, encompassing "overall musical architecture or form" roughly corresponds to Moravcsik's "very long" division while his Meso level, the level of "divisions of form" including movements, sections, phrases taking seconds or minutes, is likewise similar to Moravcsik's "long" category. Roads' Sound object (Schaeﬀer 1959; Schaeﬀer 1977): "a basic unit of musical structure" and a generalization of note (Xenakis' mini structural time scale); fraction of a second to several seconds, and his Microsound (see granular synthesis) down to the threshold of audible perception; thousands to millionths of seconds, are similarly comparable to Moravcsik's "short" and "supershort" levels of duration.

Te study of rhythm, stress, and pitch in speech is called prosody (see also: prosody (music)): it is a topic in linguistics and poetics, where it means the number of lines in a verse, the number of syllables in each line and the arrangement of those syllables as long or short, accented or unaccented. Music inherited the term "meter or metre" from the terminology of poetry (Scholes 1977b; Scholes 1977c; Latham 2002).

Te metric structure of music includes meter, tempo and all other rhythmic aspects that produce temporal regularity against which the foreground details or durational patterns of the music are projected (Winold 1975, 209-10). Te terminology of western music is notoriously imprecise in this area (Scholes 1977b). MacPherson 1930, 3 preferred to speak of "time" and "rhythmic shape", Imogen Holst (Holst 1963, 17) of "measured rhythm".

Dance music has instantly recognizable patterns of beats built upon a characteristic tempo and measure. Te Imperial Society of Teachers of Dancing defnes the tango, for example, as to be danced in 2 4 time at approximately 66 beats per minute. Te basic slow step forwards or backwards, lasting for one beat, is called a "slow", so that a full "right–left" step is equal to one 2 4 measure (Imperial Society of Teachers of Dancing 1977,[page needed]) (See Rhythm and dance).

Notation of three measures of a clave pattern preceded by one measure of steady quarter notes. Tis pattern is noted in double time relative to the one above, in one instead of two four-beat measures About this soundFour beats followed by three Clave patterns (help·info). Te general classifcations of metrical rhythm, measured rhythm, and free rhythm may be distinguished (Cooper 1973, 30). Metrical or divisive rhythm, by far the most common in Western music calculates each time value as a multiple or fraction of the beat. Normal accents re-occur regularly providing systematical grouping (measures). Measured rhythm (additive rhythm) also calculates each time value as a multiple or fraction of a specifed time unit but the accents do not recur regularly within the cycle. Free rhythm is where there is neither (Cooper 1973, 30), such as in Christian chant, which has a basic pulse but a freer rhythm, like the rhythm of prose compared to that of verse (Scholes 1977c). See Free time (music).

Finally some music, such as some graphically scored works since the 1950s and non-European music such as Honkyoku repertoire for shakuhachi, may be considered ametric (Karpinski 2000, 19). Senza misura is an Italian musical term for "without meter", meaning to play without a beat, using time to measure how long it will take to play the bar (Forney and Machlis 2007[page needed]).

A composite rhythm is the durations and patterns (rhythm) produced by amalgamating all sounding parts of a musical texture. In music of the common practice period, the composite rhythm usually confrms the meter, often in metric or even- note patterns identical to the pulse on a specifc metric level. White defnes composite rhythm as, "the resultant overall rhythmic articulation among all the voices of a contrapuntal texture" (White 1976, 136.). Tis concept was concurrently defned as “attack point rhythm” by Maury Yeston in 1976 as “the extreme rhythmic foreground of a composition – the absolute surface of articulated movement” (Yeston 1976, 41–42).

A chord, in music, is any harmonic set of pitches consisting of three or more notes (also called "pitches") that are heard as if sounding simultaneously (two pitches played together results in an interval).[1][2] (For many practical and theoretical purposes, arpeggios and broken chords, or sequences of chord tones, may also be considered as chords.)

Chords and sequences of chords are frequently used in modern West African[3] and Oceanic music,[4] Western classical music, and Western popular music; yet, they are absent from the music of many other parts of the world.[5]

In tonal Western classical music (music with a tonic key or "home key"), the most frequently encountered chords are triads, so called because they consist of three distinct notes: the root note, and intervals of a third and a ffth above the root note.

411 Other chords with more than three notes include added tone chords, extended chords and tone clusters, which are used in contemporary classical music, jazz and other genres.

An ordered series of chords is called a chord progression.[6] One example of a widely used chord progression in Western traditional music and blues is the 12 bar blues progression. Although any chord may in principle be followed by any other chord, certain patterns of chords are more common in Western music, and some patterns have been accepted as establishing the key (tonic note) in common-practice harmony—notably the movement between tonic and dominant chords.[citation needed] To describe this, Western music theory has developed the practice of numbering chords using Roman numerals[7] which represent the number of diatonic steps up from the tonic note of the scale.

Common ways of notating or representing chords[8] in Western music (other than conventional staﬀ notation) include Roman numerals, the Nashville number system, fgured bass, macro symbols (sometimes used in modern musicology), and chord charts.

While scale degrees are typically represented in musical analysis or musicology articles with Arabic numerals (e.g., 1, 2, 3..., sometimes with a circumfex above the numeral: scale degree 1, scale degree 2, scale degree 3...), the triads (three-note chords) that have these degrees as their roots are often identifed by Roman numerals (e.g., I, IV, V, which in the key of C major would be the triads C major, F major, G major). In some conventions (as in this and related articles) upper-case Roman numerals indicate major triads (e.g., I, IV, V) while lower-case Roman numerals indicate minor triads (e.g., I for a major chord and i for a minor chord, or using the major key, ii, iii and vi representing typical diatonic minor triads): other writers, (e.g. Schoenberg) use upper case Roman numerals for both major and minor triads. Some writers use upper-case Roman numerals to indicate the chord is diatonic in the major scale, and lower-case Roman numerals to indicate that the chord is diatonic in the minor scale. Diminished triads may be represented by lower-case Roman numerals with a degree symbol (e.g., viio7 indicates a diminished seventh chord built on the seventh scale degree; in the key of C major, this chord would be b diminished seventh, which consists of the notes B, D, F and G♯).

Roman numerals can also be used in stringed instrument notation to indicate the position or string to play. In some string music, the string on which it is suggested that the performer play the note is indicated with a Roman numeral (e.g., on a four-string orchestral string instrument (violin, viola, cello or double bass), I indicates the highest-pitched, thinnest string and IV indicates the lowest-pitched, thickest bass string). In some orchestral parts, chamber music and solo works for string instruments, the composer specifes to the performer which string should be used with the Roman numeral. Alternately, the note name of the string that the composer wishes the performer to use are stated using letters (e.g., "sul G" means "play on the G string”).

In music theory, scale degree refers to the position of a particular note on a scale[3] relative to the tonic, the frst and main note of the scale from which each octave is assumed to begin. Degrees are useful for indicating the size of intervals and chords, and whether they are major or minor.

In the most general sense, the scale degree merely is the number given to each step of the scale, usually starting with 1=tonic. Defning it like this implies that a tonic is specifed. For instance the 7-tone diatonic scale may become the major scale once the proper degree has been chosen as tonic (e.g. the C-major scale C–D–E–F–G–A–B, in which C is the tonic). If the scale has no tonic, the starting degree must be chosen arbitrarily. In set theory, for instance, the 12 degrees of the chromatic scale usually are numbered starting from C=0, the twelve pitch classes being numbered from 0 to 11.

In a more specifc sense, scale degrees are given names that indicate their particular function within the scale. Tis defnition implies a functional scale, as is the case in tonal music.

Te expression scale step is sometimes used synonymously with scale degree, but it may alternatively refer to the distance between two successive and adjacent scale degrees (see Steps and skips). Te terms "whole step" and "half step" are commonly used as interval names (though "whole scale step" or "half scale step" are not used). Te number of scale degrees and the distance between them together defne the scale they are in.

In Schenkerian analysis, "scale degree" (or "scale step") translates Schenker's German Stufe, denoting "a chord having gained structural signifcance" (see Schenkerian analysis: Harmony).

In music, the tonic is the frst scale degree of a diatonic scale (the frst note of a scale) and the tonal center or fnal resolution tone[4] that is commonly used in the fnal cadence in tonal (musical key-based) classical music, popular music and traditional music. Te triad formed on the tonic note, the tonic chord, is thus the most signifcant chord in these styles of

412 music. More generally, the tonic is the pitch upon which all other pitches of a piece are hierarchically referenced. Scales are named after their tonics, thus the tonic of the scale of C is the note C.

In very much conventionally tonal music, harmonic analysis will reveal a broad prevalence of the primary (often triadic) harmonies: tonic, dominant, and subdominant (i.e., I and its chief auxiliaries a 5th removed), and especially the frst two of these.

Te tonic is often confused with the root, which is the reference note of a chord, rather than that of the scale. Most chords (e.g., ii, IV, V) are not tonic chords.

Te tonic chord is represented with the Roman numeral I (if major) or i (if minor). Te other types of chords are given diﬀerent Roman numerals, such as (in a major key) ii for the chord built on the second scale degree, IV for the chord built on the fourth scale degree, V for the chord built on the ffth scale degree, and so on.

A melody (from Greek μελῳδία, melōidía, "singing, chanting"),[1] also tune, voice, or line, is a linear succession of musical tones that the listener perceives as a single entity. In its most literal sense, a melody is a combination of pitch and rhythm, while more fguratively, the term can include successions of other musical elements such as tonal color. It may be considered the foreground to the background accompaniment. A line or part need not be a foreground melody.

Melodies often consist of one or more musical phrases or motifs, and are usually repeated throughout a composition in various forms. Melodies may also be described by their melodic motion or the pitches or the intervals between pitches (predominantly conjunct or disjunct or with further restrictions), pitch range, tension and release, continuity and coherence, cadence, and shape.

Te true goal of music—its proper enterprise—is melody. All the parts of harmony have as their ultimate purpose only beautiful melody. Terefore, the question of which is the more signifcant, melody or harmony, is futile. Beyond doubt, the means is subordinate to the end.

— Johann Philipp Kirnberger (1771)[2]

Given the many and varied elements and styles of melody "many extant explanations [of melody] confne us to specifc stylistic models, and they are too exclusive."[3] Paul Narveson claimed in 1984 that more than three-quarters of melodic topics had not been explored thoroughly.[4]

Te melodies existing in most European music written before the 20th century, and popular music throughout the 20th century, featured "fxed and easily discernible frequency patterns", recurring "events, often periodic, at all structural levels" and "recurrence of durations and patterns of durations".[3]

Melodies in the 20th century "utilized a greater variety of pitch resources than ha[d] been the custom in any other historical period of Western music." While the diatonic scale was still used, the chromatic scale became "widely employed."[3] Composers also allotted a structural role to "the qualitative dimensions" that previously had been "almost exclusively reserved for pitch and rhythm". Kliewer states, "Te essential elements of any melody are duration, pitch, and quality (timbre), texture, and loudness.[3] Tough the same melody may be recognizable when played with a wide variety of timbres and dynamics, the latter may still be an "element of linear ordering”[3]

In western music theory, a diatonic scale is a heptatonic scale that includes fve whole steps (whole tones) and two half steps (semitones) in each octave, in which the two half steps are separated from each other by either two or three whole steps, depending on their position in the scale. Tis pattern ensures that, in a diatonic scale spanning more than one octave, all the half steps are maximally separated from each other (i.e. separated by at least two whole steps).

Te seven pitches of any diatonic scale can also be obtained by using a chain of six perfect ffths. For instance, the seven natural pitches that form the C-major scale can be obtained from a stack of perfect ffths starting from F:

F—C—G—D—A—E—B

Any sequence of seven successive natural notes, such as C–D–E–F–G–A–B, and any transposition thereof, is a diatonic scale. Modern musical keyboards are designed so that the white notes form a diatonic scale, though transpositions of this diatonic scale require one or more black keys. A diatonic scale can be also described as two tetrachords separated by a whole tone.

413 Te term diatonic originally referred to the diatonic genus, one of the three genera of the ancient Greeks. In musical set theory, Allen Forte classifes diatonic scales as set form 7–35.

Tis article does not concern alternative seven-note diatonic scales such as the harmonic minor or the melodic minor.

Te chromatic scale is a musical scale with twelve pitches, each a semitone above or below its adjacent pitches. As a result, in 12-tone equal temperament (the most common temperament in Western music), the chromatic scale covers all 12 of the available pitches. Tus, there is only one chromatic scale.

Moreover, in equal temperament, all the semitones have the same size (100 cents). As a result, the notes of an equal- tempered chromatic scale are equally-spaced. Tis makes the chromatic scale a nondiatonic scale with no tonic because of the symmetry of its equally-spaced notes.[1]

Diﬀerent musical styles use melody in diﬀerent ways. For example:

Jazz musicians use the term "lead" or "head" to refer to the main melody, which is used as a starting point for improvisation. Rock music, melodic music, and other forms of popular music and folk music tend to pick one or two melodies (verse and chorus, sometimes with a third, contrasting melody known as a bridge or middle eight) and stick with them; much variety may occur in the phrasing and lyrics. Indian classical music relies heavily on melody and rhythm, and not so much on harmony, as the music contains no chord changes. Balinese gamelan music often uses complicated variations and alterations of a single melody played simultaneously, called heterophony. In western classical music, composers often introduce an initial melody, or theme, and then create variations. Classical music often has several melodic layers, called polyphony, such as those in a fugue, a type of counterpoint. Often, melodies are constructed from motifs or short melodic fragments, such as the opening of Beethoven's Fifth Symphony. Richard Wagner popularized the concept of a leitmotif: a motif or melody associated with a certain idea, person or place. While in both most popular music and classical music of the common practice period pitch and duration are of primary importance in melodies, the contemporary music of the 20th and 21st centuries pitch and duration have lessened in importance and quality has gained importance, often primary. Examples include musique concrète, klangfarbenmelodie, Elliott Carter's Eight Etudes and a Fantasy (which contains a movement with only one note), the third movement of Ruth Crawford-Seeger's String Quartet 1931 (later re-orchestrated as Andante for string orchestra), which creates the melody from an unchanging set of pitches through "dissonant dynamics" alone, and György Ligeti's Aventures, in which recurring phonetics create the linear form.

Te studies of sound and vibration are closely related. Sound, or pressure waves, are generated by vibrating structures (e.g. vocal cords); these pressure waves can also induce the vibration of structures (e.g. ear drum). Hence, attempts to reduce noise are often related to issues of vibration.

Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more diﬀerent states. Te term vibration is precisely used to describe mechanical oscillation. Familiar examples of oscillation include a swinging pendulum and alternating current.

Oscillations occur not only in mechanical systems but also in dynamic systems in virtually every area of science: for example the beating of the human heart (for circulation), business cycles in economics, predator–prey population cycles in ecology, geothermal geysers in geology, vibration of strings in guitar and other string instruments, periodic fring of nerve cells in the brain, and the periodic swelling of Cepheid variable stars in astronomy.

Te simplest mechanical oscillating system is a weight attached to a linear spring subject to only weight and tension. Such a system may be approximated on an air table or ice surface. Te system is in an equilibrium state when the spring is static. If the system is displaced from the equilibrium, there is a net restoring force on the mass, tending to bring it back to equilibrium. However, in moving the mass back to the equilibrium position, it has acquired momentum which keeps it moving beyond that position, establishing a new restoring force in the opposite sense. If a constant force such as gravity is added to the system, the point of equilibrium is shifted. Te time taken for an oscillation to occur is often referred to as the oscillatory period.

Te systems where the restoring force on a body is directly proportional to its displacement, such as the dynamics of the spring-mass system, are described mathematically by the simple harmonic oscillator and the regular periodic motion is known as simple harmonic motion. In the spring-mass system, oscillations occur because, at the static equilibrium displacement, the mass has kinetic energy which is converted into potential energy stored in the spring at the extremes of its path. Te spring-mass system illustrates some common features of oscillation, namely the existence of an equilibrium and the presence of a restoring force which grows stronger the further the system deviates from equilibrium.

414 Te harmonic oscillator and the systems it models have a single degree of freedom. More complicated systems have more degrees of freedom, for example two masses and three springs (each mass being attached to fxed points and to each other). In such cases, the behavior of each variable infuences that of the others. Tis leads to a coupling of the oscillations of the individual degrees of freedom. For example, two pendulum clocks (of identical frequency) mounted on a common wall will tend to synchronise. Tis phenomenon was frst observed by Christiaan Huygens in 1665.[1] Te apparent motions of the compound oscillations typically appears very complicated but a more economic, computationally simpler and conceptually deeper description is given by resolving the motion into normal modes.

More special cases are the coupled oscillators where energy alternates between two forms of oscillation. Well-known is the Wilberforce pendulum, where the oscillation alternates between an elongation of a vertical spring and the rotation of an object at the end of that spring.

Te vocal cords, also known as vocal folds, are folds of tissue in the throat that are key in creating sounds through oscillation called vocalization. Te size of vocal cords aﬀects the pitch of voice. Open when breathing and vibrating for speech or singing, the folds are controlled via the vagus nerve.

Tey are composed of twin infoldings of mucous membrane stretched horizontally, from back to front, across the larynx. Tey vibrate, modulating the fow of air being expelled from the lungs during phonation

As the number of degrees of freedom becomes arbitrarily large, a system approaches continuity; examples include a string or the surface of a body of water. Such systems have (in the classical limit) an infnite number of normal modes and their oscillations occur in the form of waves that can characteristically propagate.

Te mathematics of oscillation deals with the quantifcation of the amount that a sequence or function tends to move between extremes. Tere are several related notions: oscillation of a sequence of real numbers, oscillation of a real valued function at a point, and oscillation of a function on an interval (or open set).

18) Sexuality

With our diﬀerent sets of organs it could be said that the other ‘race’ are the pair male and female. For procreation the left ovary if you woman and the left ovary if for men - so aim correctly if you want too choose!

Human sexuality is the way people experience and express themselves sexually. Tis involves biological, erotic, physical, emotional, social, or spiritual feelings and behaviors. Because it is a broad term, which has varied over time, it lacks a precise defnition. Te biological and physical aspects of sexuality largely concern the human reproductive functions, including the

415 human sexual response cycle. Someone's sexual orientation can infuence that person's sexual interest and attraction for another person. Physical and emotional aspects of sexuality include bonds between individuals that is expressed through profound feelings or physical manifestations of love, trust, and care. Social aspects deal with the effects of human society on one's sexuality, while spirituality concerns an individual's spiritual connection with others. Sexuality also affects and is affected by cultural, political, legal, philosophical, moral, ethical, and religious aspects of life. especially the funk.

Interest in sexual activity typically increases when an individual reaches puberty. Opinions diﬀer on the origins of an individual's sexual orientation and sexual behavior. Some argue that sexuality is determined by genetics, while others believe it is molded by the environment, or that both of these factors interact to form the individual's sexual orientation. Tis pertains to the nature versus nurture debate. In the former, one assumes that the features of a person innately correspond to their natural inheritance, exemplifed by drives and instincts; the latter refers to the assumption that the features of a person continue to change throughout their development and nurturing, exemplifed by ego ideals and formative identifcations.

Perspectives on human coupling, reproduction and reproduction strategies, and social learning theory provide further views of sexuality. Socio-cultural aspects of sexuality include historical developments and religious beliefs. Examples of these include Jewish views on sexual pleasure within marriage and some views of other religions on avoidance of sexual pleasures. [8][page needed] Some cultures have been described as sexually repressive. Te study of sexuality also includes human identity within social groups, sexually transmitted infections (STIs/STDs), and birth control methods.

Virginity is the state of a person who has never engaged in sexual intercourse. Tere are cultural and religious traditions that place special value and signifcance on this state, predominantly towards unmarried females, associated with notions of personal purity, honor and worth.

Like chastity, the concept of virginity has traditionally involved sexual abstinence. Te concept of virginity usually involves moral or religious issues and can have consequences in terms of social status and in interpersonal relationships. Although virginity has social implications and had signifcant legal implications in some societies in the past, it has no legal consequences in most societies today.

Te term virgin originally only referred to sexually inexperienced women, but has evolved to encompass a range of defnitions, as found in traditional, modern and ethical concepts.Heterosexual individuals may or may not consider loss of virginity to occur only through penile-vaginal penetration, while people of other sexual orientations often include oral sex, anal sex or mutual masturbation in their defnitions of losing one's virginity. Te social implications of virginity still remain in many societies and can have varying eﬀects on an individual's social agency based upon location.

Chastity is sexual conduct of a person that is deemed praiseworthy and virtuous according to the moral standards and guidelines of their culture, civilization or religion. Te term has become closely associated (and is often used interchangeably) with sexual abstinence, especially before marriage and outside marriage.

Adultery (from Latin adulterium) is extramarital sex that is considered objectionable on social, religious, moral, or legal grounds. Tough what sexual activities constitute adultery varies, as well as the social, religious, and legal consequences, the concept exists in many cultures and is similar in Christianity, Islam, and Judaism. A single act of sexual intercourse is generally suﬃcient to constitute adultery, and a more long-term sexual relationship is sometimes referred to as an aﬀair.

Historically, many cultures have considered adultery to be a very serious crime. Adultery often incurred severe punishment, usually for the woman and sometimes for the man, with penalties including capital punishment, mutilation, or torture. Such punishments have gradually fallen into disfavor, especially in Western countries from the 19th century. In most Western countries, adultery itself is no longer a criminal oﬀense, but may still have legal consequences, particularly in divorce cases. For example, in fault-based family law jurisdictions, adultery almost always constitutes a ground for divorce and may be a factor in property settlement, the custody of children, the denial of alimony, etc. Adultery is not a ground for divorce in jurisdictions which have adopted a no-fault divorce model. In some societies and among certain religious adherents, adultery may aﬀect the social status of those involved, and may result in social ostracism.

In countries where adultery is a criminal offense, punishments range from fnes to caning and even capital punishment. Since the 20th century, criminal laws against adultery have become controversial, with international organizations calling for their abolition, especially in the light of several high-profle stoning cases that have occurred in some countries. Te head of the United Nations expert body charged with identifying ways to eliminate laws that discriminate against women or are discriminatory to them in terms of implementation or impact, Kamala Chandrakirana, has stated that: "Adultery must not be classifed as a criminal offence at all”. A joint statement by the United Nations Working Group on discrimination against women in law and in practice states that: "Adultery as a criminal offence violates women’s human rights".

416 In Muslim countries that follow Sharia law for criminal justice, the punishment for adultery may be stoning. Tere are ffteen countries in which stoning is authorized as lawful punishment, though in recent times it has been legally carried out only in Iran and Somalia. Most countries that criminalize adultery are those where the dominant religion is Islam, and several Sub-Saharan African Christian-majority countries, but there are some notable exceptions to this rule, namely Philippines, Taiwan, and several U.S. states. In some jurisdictions, having sexual relations with the king's wife or the wife of his eldest son constitutes treason. By analogy, in cultures which value and normally practice exclusive interpersonal relationships, sexual relations with a person outside the relationship may also be described as infdelity or cheating, and is subject to sanction.

LGBT or GLBT is an initialism that stands for lesbian, gay, bisexual, and transgender. In use since the 1990s, the term is an adaptation of the initialism LGB, which was used to replace the term gay in reference to the LGBT community beginning in the mid-to-late 1980s. Activists believed that the term gay community did not accurately represent all those to whom it referred. Tis is banned in Abran.

Te initialism has become mainstream as a self-designation; it has been adopted by the majority of sexuality and gender identity-based community centers and media in the United States, as well as some other English-speaking countries. Te term is also used in dozens of other countries.

Te initialism LGBT is intended to emphasize a diversity of sexuality and gender identity-based cultures. It may be used to refer to anyone who is non- heterosexual or non-cisgender, instead of exclusively to people who are lesbian, gay, bisexual, or transgender. To recognize this inclusion, a popular variant adds the letter Q for those who identify as queer or are questioning their sexual identity; LGBTQ has been recorded since 1996. Tose who add intersex people to LGBT groups or organizing use an extended initialism LGBTI. Some people combine the two acronyms and use the term LGBTIQ or LGBTQI. Others use LGBT + to encompass spectrums of sexuality and gender.

A lesbian is a homosexual woman who is romantically or sexually attracted to other women. Te term lesbian is also used to express sexual identity or sexual behavior regardless of sexual orientation, or as an adjective to characterize or associate nouns with female homosexuality or same-sex attraction.

Te concept of "lesbian", to diﬀerentiate women with a shared sexual orientation, is a 20th-century construct. Troughout history, women have not had the same freedom or independence to pursue homosexual relationships as men, but neither have they met the same harsh punishment as homosexual men in some societies. Instead, lesbian relationships have often been regarded as harmless and incomparable to heterosexual ones unless the participants attempted to assert privileges traditionally enjoyed by men. As a result, little in history was documented to give an accurate description of how female homosexuality is expressed. When early sexologists in the late 19th century began to categorize and describe homosexual behavior, hampered by a lack of knowledge about homosexuality or women's sexuality, they distinguished lesbians as women who did not adhere to female gender roles and incorrectly designated them mentally ill—a designation which has been reversed in the global scientifc community.

Women in homosexual relationships responded to this designation either by hiding their personal lives or accepting the label of outcast and creating a subculture and identity that developed in Europe and the United States. Following World War II, during a period of social repression when governments actively persecuted homosexuals, women developed networks to socialize with and educate each other. Greater economic and social freedom allowed them gradually to be able to determine how they could form relationships and families. With second wave feminism and growth of scholarship in women's history and sexuality in the 20th century, the defnition of lesbian broadened, sparking a debate about sexual desire as the major component to defne what a lesbian is. Some women who engage in same-sex sexual activity may reject not only identifying as lesbians but as bisexual as well, while other women's self-identifcation as lesbian may not align with their sexual orientation or sexual behavior; sexual identity is not necessarily the same as one's sexual orientation or sexual behavior, due to various reasons, such as the fear of identifying their sexual orientation in a homophobic setting.

Portrayals of lesbians in the media suggest that society at large has been simultaneously intrigued and threatened by women who challenge feminine gender roles, and fascinated and appalled with women who are romantically involved with other women. Women who adopt a lesbian identity share experiences that form an outlook similar to an ethnic identity: as homosexuals, they are unifed by the heterosexist discrimination and potential rejection they face from their families, friends, and others as a result of homophobia. As women, they face concerns separate from men. Lesbians may encounter distinct physical or mental health concerns arising from discrimination, prejudice, and minority stress. Political conditions and social attitudes also aﬀect the formation of lesbian relationships and families in open.

417 Gay is a term that primarily refers to a homosexual person or the trait of being homosexual. Te term was originally used to mean "carefree", "happy", or "bright and showy".

Te term's use as a reference to homosexuality may date as early as the late 19th century, but its use gradually increased in the 20th century. In modern English, gay has come to be used as an adjective, and as a noun, referring to the people, especially to gay males, and the practices and cultures associated with homosexuality. By the end of the 20th century, the word gay was recommended by major LGBT groups and style guides to describe people attracted to members of the same sex.

At about the same time, a new, pejorative use became prevalent in some parts of the world. Among younger speakers, the word has a meaning ranging from derision (e.g., equivalent to rubbish or stupid) to a light-hearted mockery or ridicule (e.g., equivalent to weak, unmanly, or lame). In this use, the word rarely means "homosexual", as it is often used, for example, to refer to an inanimate object or abstract concept of which one disapproves. Te extent to which these usages still retain connotations of homosexuality has been debated and harshly criticized.

Asexuality is the lack of sexual attraction to others, or low or absent interest in or desire for sexual activity. It may be considered the lack of a sexual orientation, or one of the variations thereof, alongside heterosexuality, homosexuality and bisexuality. It may also be an umbrella term used to categorize a broader spectrum of various asexual sub-identities.

Asexuality is distinct from abstention from sexual activity and from celibacy, which are behavioral and generally motivated by factors such as an individual's personal or religious beliefs. Sexual orientation, unlike sexual behavior, is believed to be “enduring". Some asexual people engage in sexual activity despite lacking sexual attraction or a desire for sex, due to a variety of reasons, such as a desire to pleasure themselves or romantic partners, or a desire to have children.

Acceptance of asexuality as a sexual orientation and feld of scientifc research is still relatively new, as a growing body of research from both sociological and psychological perspectives has begun to develop. While some researchers assert that asexuality is a sexual orientation, other researchers disagree.

Various asexual communities have started to form since the advent of the World Wide Web and social media. Te most prolifc and well-known of these communities is the Asexual Visibility and Education Network, which was founded in 2001 by David Jay.

Celibacy (from Latin, cælibatus") is the state of voluntarily being unmarried, sexually abstinent, or both, usually for religious reasons. It is often in association with the role of a religious oﬃcial or devotee. In its narrow sense, the term celibacy is applied only to those for whom the unmarried state is the result of a sacred vow, act of renunciation, or religious conviction. In a wider sense, it is commonly understood to only mean abstinence from sexual activity.

Celibacy has existed in one form or another throughout history, in virtually all the major religions of the world, and views on it have varied Similarly, the Romans viewed it as an aberration and legislated fscal penalties against it, with the sole exception granted to the Vestal Virgins. Protestantism saw a reversal of this trend in the West and the Eastern Orthodox Church never adopted it. Te Islamic attitudes toward celibacy have been complex as well; Muhammad denounced it, [citation needed] but some Suf orders embrace it.

Classical Hindu culture encouraged asceticism and celibacy in the later stages of life, after one has met his societal obligations. Jainism and Buddhism have been infuenced by Hinduism in this respect. Tere were, however, signifcant cultural diﬀerences in the various areas where Buddhism spread, which aﬀected the local attitudes toward celibacy. It was not well received in China, for example, where other religions movements such as Daoism were opposed to it. A somewhat similar situation existed in Japan, where the Shinto tradition also opposed celibacy. In most native African and American Indian religious traditions, celibacy has been viewed negatively as well, although there were exceptions like periodic celibacy practiced by some Mesoamerican warriors

Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females, or romantic or sexual attraction to people of any sex or gender identity; this latter aspect is sometimes alternatively termed pansexuality.

Te term bisexuality is mainly used in the context of human attraction to denote romantic or sexual feelings toward both men and women,and the concept is one of the three main classifcations of sexual orientation along with heterosexuality and homosexuality, all of which exist on the heterosexual–homosexual continuum. A bisexual identity does not necessarily equate to equal sexual attraction to both sexes; commonly, people who have a distinct but not exclusive sexual preference for one sex over the other also identify themselves as bisexual.

418 Bisexuality has been observed in various human societies and elsewhere in the animal kingdom throughout recorded history. Te term bisexuality, however, like the terms hetero- and homosexuality, was coined in the 19th century.

Trysexual - Try any thing sexual.

Transgender people have a gender identity or gender expression that diﬀers from their assigned sex.[ Transgender people are sometimes called transsexual if they desire medical assistance to transition from one sex to another. Transgender is also an umbrella term: in addition to including people whose gender identity is the opposite of their assigned sex (trans men and trans women), it may include people who are not exclusively masculine or feminine (people who are genderqueer or non- binary, including bigender, pangender, genderfuid, or agender). Other defnitions of transgender also include people who belong to a third gender, or conceptualize transgender people as a third gender.Infrequently, the term transgender is defned very broadly to include cross-dressers, regardless of their gender identity.

Being transgender is independent of sexual orientation: transgender people may identify as heterosexual, homosexual, bisexual, asexual, or may decline to label their sexual orientation. Te term transgender is also distinguished from intersex, a term that describes people born with physical sex characteristics "that do not ft typical binary notions of male or female bodies”. Te counterpart of transgender is cisgender, which describes persons whose gender identity or expression matches their assigned sex.

Te degree to which individuals feel genuine, authentic, and comfortable within their external appearance and accept their genuine identity has been called transgender congruence. Many transgender people experience gender dysphoria, and some seek medical treatments such as hormone replacement therapy, sex reassignment surgery, or psychotherapy. Not all transgender people desire these treatments, and some cannot undergo them for fnancial or medical reasons.

Most transgender people face discrimination in the workplace and in accessing public accommodations, and healthcare. In many places they are not legally protected from discrimination.

Homosexuality is romantic attraction, sexual attraction or sexual behavior between members of the same sex or gender. As a sexual orientation, homosexuality is "an enduring pattern of emotional, romantic, and/or sexual attractions" to people of the same sex. It "also refers to a person's sense of identity based on those attractions, related behaviors, and membership in a community of others who share those attractions."

Along with bisexuality and heterosexuality, homosexuality is one of the three main categories of sexual orientation within the heterosexual–homosexual continuum. Scientists do not know exactly what determines an individual's sexual orientation, but they believe that it is caused by a complex interplay of genetic, hormonal, and environmental infuences, and do not view it as a choice. Tey favor biologically-based theories, which point to genetic factors, the early uterine environment, both, or the inclusion of genetic and social factors. Tere is no substantive evidence which suggests parenting or early childhood experiences play a role when it comes to sexual orientation. While some people believe that homosexual activity is unnatural, scientifc research has shown that homosexuality is a normal and natural variation in human sexuality and is not in and of itself a source of negative psychological eﬀects. Tere is insuﬃcient evidence to support the use of psychological interventions to change sexual orientation.

Te most common terms for homosexual people are lesbian for females and gay for males, though gay is also used to refer generally to both homosexual males and females. Te number of people who identify as gay or lesbian and the proportion of people who have same-sex sexual experiences are diﬃcult for researchers to estimate reliably for a variety of reasons, including many gay or lesbian people not openly identifying as such due to homophobia and heterosexist discrimination. Homosexual behavior has also been documented in many non-human animal species.

Many gay and lesbian people are in committed same-sex relationships, though only recently have census forms and political conditions facilitated their visibility and enumeration. Tese relationships are equivalent to heterosexual relationships in essential psychological respects. Homosexual relationships and acts have been admired, as well as condemned, throughout recorded history, depending on the form they took and the culture in which they occurred. Since the end of the 19th century, there has been a global movement towards increased visibility, recognition, and legal rights for gay people, including the rights to marriage and civil unions, adoption and parenting, employment, military service, equal access to health care, and the introduction of anti-bullying legislation to protect gay minors.

Zoophilia is a paraphilia involving a sexual fxation on non-human animals. Bestiality is cross-species sexual activity between human and non-human animals. Te terms are often used interchangeably, but some researchers make a distinction between the attraction (zoophilia) and the act (bestiality).

419 Although sex with animals is not outlawed in some countries, in most countries, bestiality is illegal under animal abuse laws or laws dealing with buggery or crimes against nature.

Sexual arousal (also sexual excitement) is the arousal of sexual desire, during or in anticipation of sexual activity. A number of physiological responses occur in the body and mind as preparation for sexual intercourse and continue during it. Genital responses are not the only changes, but noticeable and necessary for consensual and comfortable intercourse. Male arousal will lead to an erection, and in female arousal the body's response is engorged sexual tissues such as nipples, vulva, clitoris, vaginal walls and vaginal lubrication. Mental stimuli and physical stimuli such as touch, and the internal fuctuation of hormones, can infuence sexual arousal.

Sexual arousal has several stages and may not lead to any actual sexual activity, beyond a mental arousal and the physiological changes that accompany it. Given suﬃcient sexual stimulation, sexual arousal in humans reaches its climax during an orgasm. It may also be pursued for its own sake, even in the absence of an orgasm.

Sexual desire is a motivational state and an interest in “sexual objects or activities, or as a wish, need or drive to seek out sexual objects or to engage in sexual activities”. Synonyms for sexual desire are libido, sexual attraction and lust. Sexual desire is an aspect of a person's sexuality, which varies signifcantly from one person to another, and also varies depending on circumstances at a particular time. Not every person experiences sexual desire; those who do not experience it may be labelled asexual.

Sexual desire may be the “single most common sexual event in the lives of men and women”.Sexual desire is a subjective feeling state that can “be triggered by both internal and external cues, and that may or may not result in overt sexual behaviour”. Sexual desire can be aroused through imagination and sexual fantasies, or perceiving an individual whom one fnds attractive. Sexual desire is also created and amplifed through sexual tension, which is caused by sexual desire that has yet to be consummated.

Sexual desire can be spontaneous or responsive. Sexual desire is dynamic, can either be positive or negative, and can vary in intensity depending on the desired object/person. Te sexual desire spectrum is described by Stephen B. Levine as: aversion --> disinclination --> indiﬀerence --> interest --> need --> passion.

Te production and use of sexual fantasy and thought is an important part of properly functioning sexual desire. Some physical manifestations of sexual desire in humans are; licking, sucking, puckering and touching the lips, as well as tongue protrusion.

Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., masturbation) to acts with another person (e.g., sexual intercourse, non-penetrative sex, oral sex, etc.) in varying patterns of frequency, for a wide variety of reasons. Sexual activity usually results in sexual arousal and physiological changes in the aroused person, some of which are pronounced while others are more subtle. Sexual activity may also include conduct and activities which are intended to arouse the sexual interest of another or enhance the sex life of another, such as strategies to fnd or attract partners (courtship and display behaviour), or personal interactions between individuals (for instance, foreplay or BDSM). Sexual activity may follow sexual arousal.

Human sexual activity has sociological, cognitive, emotional, behavioural and biological aspects; these include personal bonding, sharing emotions and the physiology of the reproductive system, sex drive, sexual intercourse and sexual behaviour in all its forms.

In some cultures, sexual activity is considered acceptable only within marriage, while premarital and extramarital sex are taboo. Some sexual activities are illegal either universally or in some countries or subnational jurisdictions, while some are considered contrary to the norms of certain societies or cultures. Two examples that are criminal oﬀences in most jurisdictions are sexual assault and sexual activity with a person below the local age of consent.

Masturbation is the sexual stimulation of one's own genitals for sexual arousal or other sexual pleasure, usually to the point of orgasm. Te stimulation may involve hands, fngers, everyday objects, sex toys such as vibrators, or combinations of these. Mutual masturbation (mutual manual stimulation of the genitals between partners) can be a substitute for sexual penetration. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. Various medical and psychological benefts have been attributed to a healthy attitude toward sexual activity in general and to masturbation in particular. No causal relationship is known between masturbation and any form of mental or physical disorder.

420 Masturbation has been depicted in art since prehistoric times and is mentioned and discussed in very early writings. In the 18th and 19th centuries, some European theologians and physicians described it as "heinous", "deplorable", and "hideous", but during the 20th century these taboos generally declined. Tere has been an increase in discussion and portrayal of masturbation in art, popular music, television, flms, and literature. Today, religions vary in their views of masturbation; some view it as a spiritually detrimental practice, some see it as not spiritually detrimental, and others take a situational view. Te legal status of masturbation has also varied through history and masturbation in public is illegal in most countries.

In the Western world, masturbation in private or with a partner is generally considered a normal and healthy part of sexual enjoyment. Animal masturbation has been observed in many species, both in the wild and in captivity.

Mutual masturbation (also called manual intercourse) usually involves the manual stimulation of genitals by two or more people who stimulate themselves or one another. Tis may be done in situations where the participants do not feel ready, physically able, socially at liberty, or willing to engage in any penetrative sex act, or a particular penetrative sex act, but still wish to engage in a mutual sexual activity. It is also done as part of a full repertoire of sexual activity, where it may be used as foreplay, while, for others, it is the primary sexual activity of choice.

Types of mutual masturbation include the handjob (the manual sexual stimulation of the penis or scrotum by a person on a male) and fngering (the manual sexual stimulation of the vagina, clitoris or other parts of the vulva, by a person on a female). Sexual stimulation of the genitals by using the feet may also be included, and so may manual stimulation of the anus.

Like frottage in general, mutual masturbation may be used as an alternative to penile-vaginal penetration, to preserve virginity or to prevent pregnancy. It might result in one or more of the partners achieving orgasm. If no bodily fuids are exchanged (as is common), mutual masturbation is a form of safe sex, and greatly reduces the risk of transmission of sexual diseases.

In partnered manual genital stroking to reach orgasm or expanded orgasm, both people focus on creating and experiencing an orgasm in one person. Typically, one person lies down pant-less, while his or her partner sits alongside. Te partner who is sitting uses his or her hands and fngers (typically with a lubricant) to slowly stroke the penis or clitoris and other genitals of the partner. Expanded orgasm as a mutual masturbation technique reportedly creates orgasm experiences more intense and extensive than what can be described as, or included in the defnition of, a regular orgasm. It includes a range of sensations that include orgasms that are full-bodied, and orgasms that last from a few minutes to many hours. However, this technique is not without risk of contracting sexually transmitted infections, in particular HIV. A person using his or her fnger, with a small wound, to stimulate a woman's genitals could be infected with HIV found in her vagina's fuids; likewise regarding a man's semen containing HIV, which could infect a partner who has a small exposed wound on his or her skin.

Sexual stimulation is any stimulus (including bodily contact) that leads to, enhances and maintains sexual arousal, and may lead to orgasm. Although sexual arousal may arise without physical stimulation, achieving orgasm usually requires physical sexual stimulation.

Te term sexual stimulation often implies stimulation of the genitals, but may also include stimulation of other areas of the body, stimulation of the senses (such as sight or hearing) and mental stimulation (i.e. from reading or fantasizing). Suﬃcient stimulation of the penis in males and the clitoris in females usually results in an orgasm. Stimulation can be by self (e.g., masturbation) or by a sexual partner (sexual intercourse or other sexual activity), by use of objects or tools, or by some combination of these methods.

Some people practice orgasm control, whereby a person or their sexual partner controls the level of sexual stimulation to delay orgasm, and to prolong the sexual experience leading up to orgasm.

Orgasm (from Greek ὀργασμός orgasmos "excitement, swelling"; also sexual climax) is the sudden discharge of accumulated sexual excitement during the sexual response cycle, resulting in rhythmic muscular contractions in the pelvic region characterized by sexual pleasure. Experienced by males and females, orgasms are controlled by the involuntary or autonomic nervous system. Tey are often associated with other involuntary actions, including muscular spasms in multiple areas of the body, a general euphoric sensation and, frequently, body movements and vocalizations. Te period after orgasm (known as the refractory period) is often a relaxing experience, attributed to the release of the neurohormones oxytocin and prolactin as well as endorphins (or "endogenous morphine").

Human orgasms usually result from physical sexual stimulation of the penis in males (typically accompanying ejaculation), and the clitoris in females. Sexual stimulation can be by self-practice (masturbation) or with a sex partner (penetrative sex, non-penetrative sex, or other sexual activity). 421 Te health eﬀects surrounding the human orgasm are diverse. Tere are many physiological responses during sexual activity, including a relaxed state created by prolactin, as well as changes in the central nervous system such as a temporary decrease in the metabolic activity of large parts of the cerebral cortex while there is no change or increased metabolic activity in the limbic (i.e., "bordering") areas of the brain. Tere is also a wide range of sexual dysfunctions, such as anorgasmia. Tese eﬀects impact cultural views of orgasm, such as the beliefs that orgasm and the frequency/consistency of it are important or irrelevant for satisfaction in a sexual relationship,and theories about the biological and evolutionary functions of orgasm.

Orgasm in non-human animals has been studied signifcantly less than orgasm in humans, but research on the subject is ongoing.

Males Variabilities

In men, the most common way of achieving orgasm is by physical sexual stimulation of the penis. Tis is usually accompanied by ejaculation, but it is possible, though also rare, for men to orgasm without ejaculation (known as a "dry orgasm") or to ejaculate without reaching orgasm (which may be a case of delayed ejaculation, a nocturnal emission or a case of anorgasmic ejaculation). Men may also achieve orgasm by stimulation of the prostate (see below).

Two-stage model Te traditional view of male orgasm is that there are two stages: emission following orgasm, almost instantly followed by a refractory period. In 1966, Masters and Johnson published pivotal research about the phases of sexual stimulation. Teir work included women and men, and, unlike Alfred Kinsey in 1948 and 1953, tried to determine the physiological stages before and after orgasm.

Masters and Johnson argued that, in the frst stage, "accessory organs contract and the male can feel the ejaculation coming; two to three seconds later the ejaculation occurs, which the man cannot constrain, delay, or in any way control" and that, in the second stage, "the male feels pleasurable contractions during ejaculation, reporting greater pleasure tied to a greater volume of ejaculate". Tey reported that, unlike females, "for the man the resolution phase includes a superimposed refractory period" and added that "many males below the age of 30, but relatively few thereafter, have the ability to ejaculate frequently and are subject to only very short refractory periods during the resolution phase". Masters and Johnson equated male orgasm and ejaculation and maintained the necessity for a refractory period between orgasms.

Subsequent and multiple orgasms Tere has been little scientifc study of multiple orgasm in men. In contrast to the two-stage model of male orgasm, Kahn (1939) equalized orgasm and ejaculation and stated that several orgasms can occur and that "indeed, some men are capable of following [an orgasm] up with a third and a fourth" orgasm. Tough it is rare for men to achieve multiple orgasms, Kahn's assertion that some men are capable of achieving them is supported by men who have reported having multiple, consecutive orgasms, particularly without ejaculation. Males who experience dry orgasms can often produce multiple orgasms, as the refractory period is reduced.

An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefy responsible for the refractory period, and the amount by which oxytocin is increased may aﬀect the length of each refractory period. Another chemical which is considered to be responsible for the male refractory period is prolactin, which represses dopamine, which is responsible for sexual arousal. Because of this, there is currently an experimental interest in drugs which inhibit prolactin, such as cabergoline (also known as Cabeser or Dostinex). Anecdotal reports on cabergoline suggest it may be able to eliminate the refractory period altogether, allowing men to experience multiple ejaculatory orgasms in rapid succession. At least one scientifc study supports these claims, although cabergoline is a hormone-altering drug and has many potential side eﬀects. It has not been approved for treating sexual dysfunction.

Another possible reason for the lack or absence of a refractory period in men may be an increased infusion of the hormone oxytocin. It is believed that the amount by which oxytocin is increased may aﬀect the length of each refractory period. A scientifc study to successfully document natural, fully ejaculatory, multiple orgasms in an adult man was conducted at Rutgers University in 1995. During the study, six fully ejaculatory orgasms were experienced in 36 minutes, with no apparent refractory period. Later, P. Haake et al. observed a single male individual producing multiple orgasms without elevated prolactin response.

Females

Study for Pasadena Lifesavers, prismacolor, 1968. Judy Chicago created the Pasadena Lifesavers, a series of abstract paintings that blended colors to create an illusion that the shapes "turn, dissolve, open, close, vibrate, gesture, wiggle," to represent her own discovery that she was multi-orgasmic.

422 Orgasmic factors and variabilities In women, the most common way to achieve orgasm is by physical sexual stimulation of the clitoris; general statistics indicate that 70–80 percent of women require direct clitoral stimulation (consistent manual, oral or other concentrated friction against the external parts of the clitoris) to achieve orgasm, though indirect clitoral stimulation (for example, via vaginal penetration) may also be suﬃcient. Te Mayo Clinic stated, "Orgasms vary in intensity, and women vary in the frequency of their orgasms and the amount of stimulation necessary to trigger an orgasm." Clitoral orgasms are easier to achieve because the glans of the clitoris, or clitoris as a whole, has more than 8,000 sensory nerve endings, which is as many (or more in some cases) nerve endings present in the human penis or glans penis. As the clitoris is homologous to the penis, it is the equivalent in its capacity to receive sexual stimulation.

One misconception, particularly in older research publications, is that the vagina is completely insensitive. However, there are areas in the anterior vaginal wall and between the top junction of the labia minora and the urethra that are especially sensitive. With regard to specifc density of nerve endings, while the area commonly described as the G-spot may produce an orgasm, and the urethral sponge, an area in which the G-spot may be found, runs along the "roof" of the vagina and can create pleasurable sensations when stimulated, intense sexual pleasure (including orgasm) from vaginal stimulation is occasional or otherwise absent because the vagina has signifcantly fewer nerve endings than the clitoris. Te greatest concentration of vaginal nerve endings are at the lower third (near the entrance) of the vagina.

Sex educator Rebecca Chalker states that only one part of the clitoris, the urethral sponge, is in contact with the penis, fngers, or a dildo in the vagina. Hite and Chalker state that the tip of the clitoris and the inner lips, which are also very sensitive, are not receiving direct stimulation during penetrative intercourse. Because of this, some couples may engage in the woman on top position or the coital alignment technique to maximize clitoral stimulation. For some women, the clitoris is very sensitive after climax, making additional stimulation initially painful.

Masters and Johnson argued that all women are potentially multiply orgasmic, but that multiply orgasmic men are rare, and stated that "the female is capable of rapid return to orgasm immediately following an orgasmic experience, if restimulated before tensions have dropped below plateau phase response levels". Tough generally reported that women do not experience a refractory period and thus can experience an additional orgasm, or multiple orgasms, soon after the frst one, some sources state that both men and women experience a refractory period because women may also experience a period after orgasm in which further sexual stimulation does not produce excitement. After the initial orgasm, subsequent orgasms for women may be stronger or more pleasurable as the stimulation accumulates.

Clitoral and vaginal categories Discussions of female orgasm are complicated by orgasms in women typically being divided into two categories: clitoral orgasm and vaginal (or G-spot) orgasm. In 1973, Irving Singer theorized that there are three types of female orgasms; he categorized these as vulval, uterine, and blended, but because he was a philosopher, "these categories were generated from descriptions of orgasm in literature rather than laboratory studies". In 1982, Ladas, Whipple and Perry also proposed three categories: the tenting type (derived from clitoral stimulation), the A-frame type (derived from G-spot stimulation), and the blended type (derived from clitoral and G-spot stimulation). In 1999, Whipple and Komisaruk proposed cervix stimulation as being able to cause a fourth type of female orgasm.

Female orgasms by means other than clitoral or vaginal/G-spot stimulation are less prevalent in scientifc literature and most scientists contend that no distinction should be made between "types" of female orgasm. Tis distinction began with Sigmund Freud, who postulated the concept of "vaginal orgasm" as separate from clitoral orgasm. In 1905, Freud stated that clitoral orgasms are purely an adolescent phenomenon and that upon reaching puberty, the proper response of mature women is a change-over to vaginal orgasms, meaning orgasms without any clitoral stimulation. While Freud provided no evidence for this basic assumption, the consequences of this theory were considerable. Many women felt inadequate when they could not achieve orgasm via vaginal intercourse alone, involving little or no clitoral stimulation, as Freud's theory made penile-vaginal intercourse the central component to women's sexual satisfaction.

Te frst major national surveys of sexual behavior were the Kinsey Reports. Alfred Kinsey was the frst researcher to harshly criticize Freud's ideas about female sexuality and orgasm when, through his interviews with thousands of women, Kinsey found that most of the women he surveyed could not have vaginal orgasms. He "criticized Freud and other theorists for projecting male constructs of sexuality onto women" and "viewed the clitoris as the main center of sexual response" and the vagina as "relatively unimportant" for sexual satisfaction, relaying that "few women inserted fngers or objects into their vaginas when they masturbated". He "concluded that satisfaction from penile penetration [is] mainly psychological or perhaps the result of referred sensation".

Masters and Johnson's research into the female sexual response cycle, as well as Shere Hite's, generally supported Kinsey's fndings about female orgasm. Masters and Johnson's research on the topic came at the time of the second-wave feminist

423 movement, and inspired feminists such as Anne Koedt, author of Te Myth of the Vaginal Orgasm, to speak about the "false distinction" made between clitoral and vaginal orgasms and women's biology not being properly analyzed.

Clitoral and vaginal relationships G-spot § Society and culture Accounts that the vagina is capable of producing orgasms continue to be subject to debate because, in addition to the vagina's low concentration of nerve endings, reports of the G-spot's location are inconsistent—it appears to be nonexistent in some women and may be an extension of another structure, such as the Skene's gland or the clitoris, which is a part of the Skene's gland. In a January 2012 Te Journal of Sexual Medicine review examining years of research into the existence of the G-spot, scholars stated that "[r]eports in the public media would lead one to believe the G-spot is a well-characterized entity capable of providing extreme sexual stimulation, yet this is far from the truth".

Possible explanations for the G-spot were examined by Masters and Johnson, who were the frst researchers to determine that the clitoral structures surround and extend along and within the labia. In addition to observing that the majority of their female subjects could only have clitoral orgasms, they found that both clitoral and vaginal orgasms had the same stages of physical response. On this basis, they argued that clitoral stimulation is the source of both kinds of orgasms, [59][60] reasoning that the clitoris is stimulated during penetration by friction against its hood; their notion that this provides the clitoris with suﬃcient sexual stimulation has been criticized by researchers such as Elisabeth Lloyd.

Australian urologist Helen O'Connell's 2005 research additionally indicates a connection between orgasms experienced vaginally and the clitoris, suggesting that clitoral tissue extends into the anterior wall of the vagina and that therefore clitoral and vaginal orgasms are of the same origin. Some studies, using ultrasound, have found physiological evidence of the G-spot in women who report having orgasms during vaginal intercourse, but O'Connell suggests that the clitoris's interconnected relationship with the vagina is the physiological explanation for the conjectured G-spot. Having used MRI technology which enabled her to note a direct relationship between the legs or roots of the clitoris and the erectile tissue of the "clitoral bulbs" and corpora, and the distal urethra and vagina, she stated that the vaginal wall is the clitoris; that lifting the skin oﬀ the vagina on the side walls reveals the bulbs of the clitoris—triangular, crescental masses of erectile tissue. O'Connell et al., who performed dissections on the female genitals of cadavers and used photography to map the structure of nerves in the clitoris, were already aware that the clitoris is more than just its glans and asserted in 1998 that there is more erectile tissue associated with the clitoris than is generally described in anatomical textbooks. Tey concluded that some females have more extensive clitoral tissues and nerves than others, especially having observed this in young cadavers as compared to elderly ones, and therefore whereas the majority of females can only achieve orgasm by direct stimulation of the external parts of the clitoris, the stimulation of the more generalized tissues of the clitoris via intercourse may be suﬃcient for others.

French researchers Odile Buisson and Pierre Foldès reported similar fndings to that of O'Connell's. In 2008, they published the frst complete 3D sonography of the stimulated clitoris, and republished it in 2009 with new research, demonstrating the ways in which erectile tissue of the clitoris engorges and surrounds the vagina, arguing that women may be able to achieve vaginal orgasm via stimulation of the G-spot because the highly innervated clitoris is pulled closely to the anterior wall of the vagina when the woman is sexually aroused and during vaginal penetration. Tey assert that since the front wall of the vagina is inextricably linked with the internal parts of the clitoris, stimulating the vagina without activating the clitoris may be next to impossible. In their 2009 published study, the "coronal planes during perineal contraction and fnger penetration demonstrated a close relationship between the root of the clitoris and the anterior vaginal wall". Buisson and Foldès suggested "that the special sensitivity of the lower anterior vaginal wall could be explained by pressure and movement of clitoris's root during a vaginal penetration and subsequent perineal contraction”.

Supporting a distinct G-spot is a study by Rutgers University, published 2011, which was the frst to map the female genitals onto the sensory portion of the brain; brain scans showed that the brain registered distinct feelings between stimulating the clitoris, the cervix and the vaginal wall – where the G-spot is reported to be – when several women stimulated themselves in a functional magnetic resonance (fMRI) machine. "I think that the bulk of the evidence shows that the G- spot is not a particular thing," stated Barry Komisaruk, head of the research fndings. "It's not like saying, 'What is the thyroid gland?' Te G-spot is more of a thing like New York City is a thing. It's a region, it's a convergence of many different structures." Commenting on Komisaruk's research and other fndings, Emmanuele Jannini, a professor of endocrinology at the University of Aquila in Italy, acknowledged a series of essays published in March 2012 in Te Journal of Sexual Medicine, which document evidence that vaginal and clitoral orgasms are separate phenomena that activate different areas of the brain and possibly suggest key psychological differences between women.

Other factors and research Regular diﬃculty reaching orgasm after ample sexual stimulation, known as anorgasmia, is signifcantly more common in women than in men (see below). In addition to sexual dysfunction being a cause for women's inability to reach orgasm, or the amount of time for sexual arousal needed to reach orgasm being variable and longer in women than in men, other factors

424 include a lack of communication between sexual partners about what is needed for the woman to reach orgasm, feelings of sexual inadequacy in either partner, a focus on only penetration (vaginal or otherwise), and men generalizing women's trigger for orgasm based on their own sexual experiences with other women.

Scholars state "many couples are locked into the idea that orgasms should be achieved only through intercourse [vaginal sex]" and that "[e]ven the word foreplay suggests that any other form of sexual stimulation is merely preparation for the 'main event.'...... Because women reach orgasm through intercourse less consistently than men, they are more likely than men to have faked an orgasm".[5] Sex counselor Ian Kerner stated, "It's a myth that using the penis is the main way to pleasure a woman." He cites research concluding that women reach orgasm about 25% of the time with intercourse, compared with 81% of the time during oral sex (cunnilingus).

In the frst large-scale empirical study worldwide to link specifc practices with orgasm, reported in the Journal of Sex Research in 2006, demographic and sexual history variables were comparatively weakly associated with orgasm. Data was analyzed from the Australian Study of Health and Relationships, a national telephone survey of sexual behavior and attitudes and sexual health knowledge carried out in 2001–2002, with a representative sample of 19,307 Australians aged 16 to 59. Practices included "vaginal intercourse alone (12%), vaginal + manual stimulation of the man's and/or woman's genitals (49%), and vaginal intercourse + manual + oral (32%)" and the "[e]ncounters may also have included other practices. Men had an orgasm in 95% of encounters and women in 69%. Generally, the more practices engaged in, the higher a woman's chance of having an orgasm. Women were more likely to reach orgasm in encounters including cunnilingus".

Other studies suggest that women exposed to lower levels of prenatal androgens are more likely to experience orgasm during vaginal intercourse than other women.

Exercise-induced Kinsey, in his 1953 book Sexual Behavior in the Human Female, stated that exercise could bring about sexual pleasure, including orgasm. A review in 1990 on the sexual response itself as exercise, reviewed the literature and stated that the feld was poorly researched; it also said that studies had found that aerobic or isotonic exercise that resembles sexual activity or sexual positions can induce sexual pleasure, including orgasm. A 2007 review of the relationship between pelvic foor dysfunction and sexual problems in men and women found that they are commonly linked and suggested that physical therapy strengthening the pelvic foor could help address the sexual problems but that it was not well studied enough to recommend.[69] Starting in at least 2007, the term, "coregasm" was used in popular media to refer to exercise-induced orgasm and an extensive discussion of the "yogasm" occurred in a 2011 Daily Beast posting. A paper published in 2012 presented results of an online survey of women who had experienced an orgasm or other sexual pleasure during exercise. Te paper was widely discussed in popular media when it was published. Te authors of the paper said that research on the relationship between exercise and sexual response was still lacking.

Anal and nipple stimulation in males and females See also: Pegging and prostate massage In both sexes, pleasure can be derived from the nerve endings around the anus and the anus itself, such as during anal sex. It is possible for men to achieve orgasms through prostate stimulation alone. Te prostate is located next to the rectum and is the larger, more developed male homologue (variation) to the Skene's glands (which are believed to be connected to the female G-spot). Prostate stimulation can produce a "deeper" orgasm, described by some men as more widespread and intense, longer-lasting, and allowing for greater feelings of ecstasy than orgasm elicited by penile stimulation only. However, though the experiences are diﬀerent, male orgasms by penile stimulation are also centered in the prostate gland. Sex toys designed for prostate stimulation are, according to Wibowo and Wassersug, one of the means that help men achieve multiple orgasms. Te practice of pegging (consisting of a woman penetrating a man's anus with a strap-on dildo) stimulates the prostate. It is also common for men to not reach orgasm as receptive partners solely from anal sex, and it may be that it is typical that receptive male partners do not reach orgasm solely by this activity.

For women, other than nerve endings found within the anus and rectum, anal pleasure may be achieved through indirect stimulation of the clitoral "legs" — extensions of the clitoris that fank the urethra, urethral sponge, and vagina, and extend back toward the pubis. Indirect stimulation of the clitoris through anal penetration may be caused by the shared sensory nerves; especially the pudendal nerve, which gives oﬀ the inferior anal nerves and divides into two terminal branches: the perineal nerve and the dorsal nerve of the clitoris. Te G-spot area, considered to be interconnected with the clitoris, may also be accessible through anal penetration; besides the shared anatomy of the aforementioned sensory nerves, orgasm by stimulation of the clitoris or G-spot area through anal penetration is made possible because of the close proximity between the vaginal cavity and the rectal cavity, allowing for general indirect stimulation. Achieving orgasm solely by anal stimulation is rare among women. Direct stimulation of the clitoris, G-spot area, or both, during anal sex can help some women enjoy the activity and reach orgasm from it.

425 Te aforementioned orgasms are sometimes referred to as anal orgasms, but sexologists and sex educators generally believe that orgasms derived from anal penetration are the result of the anus's proximity to the clitoris or G-spot in women, and the prostate in men, rather than orgasms originating from the anus itself. Author Jack Morin, however, has postulated that "anal orgasm" has nothing to do with the prostate orgasm, although the two are often confused.

On rare occasions, stimulation of the breast area during sexual intercourse or foreplay, or solely having the breasts fondled, creates mild to intense orgasms, sometimes referred to as a breast orgasm or nipple orgasm, in some women. According to one study, by Herbert Otto, which questioned 213 women, 29% of them had experienced an orgasm of this kind at one time or another. Research suggests that the sensations are genital orgasms caused by nipple stimulation, and may also be directly linked to "the genital area of the brain”. An orgasm is believed to occur in part because of the hormone oxytocin, which is produced in the body during sexual excitement and arousal. It has also been shown that oxytocin is produced when a man or woman's nipples are stimulated and become erect.

A study published in the July 2011 Te Journal of Sexual Medicine was the frst to map the female genitals onto the sensory portion of the brain, and concluded that sensation from the nipples travels to the same part of the brain as sensations from the vagina, clitoris and cervix. "Four major nerves bring signals from women's genitals to their brains," said researcher Barry Komisaruk of Rutgers University. "Te pudendal nerve connects the clitoris, the pelvic nerve carries signals from the vagina, the hypogastric nerve connects with the cervix and uterus, and the vagus nerve travels from the cervix and uterus without passing through the spinal cord (making it possible for some women to achieve orgasm even though they have had complete spinal cord injuries)." Komisaruk cited one reason for this possibility to be oxytocin, which is also released during labor and triggers uterus contractions. Nipple stimulation triggers uterine contractions, which then produce a sensation in the genital area of the brain. Komisaruk also relayed, however, that preliminary data suggests that nipple nerves may directly link up with the relevant parts of the brain without uterine mediation, acknowledging the men in his study who showed the same pattern of nipple stimulation activating genital brain regions.

Physiological responses Masters and Johnson were some of the frst researchers to study the sexual response cycle in the early 1960s, based on the observation of 382 women and 312 men. Tey described a cycle that begins with excitement as blood rushes into the genitals, then reaches a plateau during which they are fully aroused, which leads to orgasm, and fnally resolution, in which the blood leaves the genitals.

In the 1970s, Helen Singer Kaplan added the category of desire to the cycle, which she argued precedes sexual excitation. She stated that emotions of anxiety, defensiveness and the failure of communication can interfere with desire and orgasm. In the late 1980s and after, Rosemary Basson proposed a more cyclical alternative to what had largely been viewed as linear progression. In her model, desire feeds arousal and orgasm, and is in turn fueled by the rest of the orgasmic cycle. Rather than orgasm being the peak of the sexual experience, she suggested that it is just one point in the circle and that people could feel sexually satisfed at any stage, reducing the focus on climax as an end-goal of all sexual activity.

Males As a man nears orgasm during stimulation of the penis, he feels an intense and highly pleasurable pulsating sensation of neuromuscular euphoria. Tese pulses are a series of throbbing sensations of the bulbospongiosus muscles that begin in the anal sphincter and travel to the tip of the penis. Tey eventually increase in speed and intensity as the orgasm approaches, until a fnal "plateau" (the orgasmic) pleasure sustained for several seconds. Te length of a man's orgasm has been estimated at 10–15 seconds on average, though it is possible for them to last up to 30 seconds.

During orgasm, a human male experiences rapid, rhythmic contractions of the anal sphincter, the prostate, and the muscles of the penis. Te sperm are transmitted up the vas deferens from the testicles, into the prostate gland as well as through the seminal vesicles to produce what is known as semen. Te prostate produces a secretion that forms one of the components of ejaculate. Except for in cases of a dry orgasm, contraction of the sphincter and prostate force stored semen to be expelled through the penis's urethral opening. Te process takes from three to ten seconds, and produces a pleasurable feeling. Ejaculation may continue for a few seconds after the euphoric sensation gradually tapers oﬀ. It is believed that the exact feeling of "orgasm" varies from one man to another. Normally, as a man ages, the amount of semen he ejaculates diminishes, and so does the duration of orgasms. Tis does not normally aﬀect the intensity of pleasure, but merely shortens the duration. After ejaculation, a refractory period usually occurs, during which a man cannot achieve another orgasm. Tis can last anywhere from less than a minute to several hours or days, depending on age and other individual factors.

Females

426 Sinnenrausch (ca. 1890), by Franciszek Żmurko A woman's orgasm may last slightly longer or much longer than a man's. Women's orgasms have been estimated to last, on average, approximately 20 seconds, and to consist of a series of muscular contractions in the pelvic area that includes the vagina, the uterus, and the anus. For some women, on some occasions, these contractions begin soon after the woman reports that the orgasm has started and continue at intervals of about one second with initially increasing, and then reducing, intensity. In some instances, the series of regular contractions is followed by a few additional contractions or shudders at irregular intervals. In other cases, the woman reports having an orgasm, but no pelvic contractions are measured at all.

Women's orgasms are preceded by erection of the clitoris and moistening of the opening of the vagina. Some women exhibit a sex fush, a reddening of the skin over much of the body due to increased blood fow to the skin. As a woman nears orgasm, the clitoral glans retracts under the clitoral hood, and the labia minora (inner lips) become darker. As orgasm becomes imminent, the outer third of the vagina tightens and narrows, while overall the vagina lengthens and dilates and also becomes congested from engorged soft tissue.

Elsewhere in the body, myofbroblasts of the nipple-areolar complex contract, causing erection of the nipples and contraction of the areolar diameter, reaching their maximum at the start of orgasm. A woman experiences full orgasm when her uterus, vagina, anus, and pelvic muscles undergo a series of rhythmic contractions. Most women fnd these contractions very pleasurable.

Researchers from the University Medical Center of Groningen in the Netherlands correlated the sensation of orgasm with muscular contractions occurring at a frequency of 8–13 Hz centered in the pelvis and measured in the anus. Tey argue that the presence of this particular frequency of contractions can distinguish between voluntary contraction of these muscles and spontaneous involuntary contractions, and appears to more accurately correlate with orgasm as opposed to other metrics like heart rate that only measure excitation. Tey assert that they have identifed "[t]he frst objective and quantitative measure that has a strong correspondence with the subjective experience that orgasm ultimately is" and state that the measure of contractions that occur at a frequency of 8–13 Hz is specifc to orgasm. Tey found that using this metric they could distinguish from rest, voluntary muscular contractions, and even unsuccessful orgasm attempts.

Since ancient times in Western Europe, women could be medically diagnosed with a disorder called female hysteria, the symptoms of which included faintness, nervousness, insomnia, fuid retention, heaviness in abdomen, muscle spasm, shortness of breath, irritability, loss of appetite for food or sex, and "a tendency to cause trouble". Women considered suﬀering from the condition would sometimes undergo "pelvic massage" — stimulation of the genitals by the doctor until the woman experienced "hysterical paroxysm" (i.e., orgasm). Paroxysm was regarded as a medical treatment, and not a sexual release.[99] Te disorder has ceased to be recognized as a medical condition since the 1920s.

Brain Tere have been very few studies correlating orgasm and brain activity in real time. One study examined 12 healthy women using a positron emission tomography (PET) scanner while they were being stimulated by their partners. Brain changes were observed and compared between states of rest, sexual stimulation, faked orgasm, and actual orgasm. Diﬀerences were reported in the brains of men and women during stimulation. However, changes in brain activity were observed in both sexes in which the brain regions associated with behavioral control, fear and anxiety shut down. Regarding these changes, Gert Holstege said in an interview with Te Times, "What this means is that deactivation, letting go of all fear and anxiety, might be the most important thing, even necessary, to have an orgasm."

While stroking the clitoris, the parts of the female brain responsible for processing fear, anxiety and behavioral control start to diminish in activity. Tis reaches a peak at orgasm when the female brain's emotion centers are eﬀectively closed down to produce an almost trance-like state. Holstege is quoted as saying, at the 2005 meeting of the European Society for Human Reproduction and Development: "At the moment of orgasm, women do not have any emotional feelings."

Initial reports indicated that it was difficult to observe the effects of orgasm on men using PET scans, because the duration of the male orgasm was shorter. However, a subsequent report by Rudie Kortekaas, et al. stated, "Gender commonalities were most evident during orgasm... From these results, we conclude that during the sexual act, differential brain responses across genders are principally related to the stimulatory (plateau) phase and not to the orgasmic phase itself."

Research has shown that as in women, the emotional centers of a man's brain also become deactivated during orgasm but to a lesser extent than in women. Brain scans of both sexes have shown that the pleasure centers of a man's brain show more intense activity than in women during orgasm.

427 Human brain wave patterns show distinct changes during orgasm, which indicate the importance of the limbic system in the orgasmic response.Male and female brains demonstrate similar changes during orgasm, with brain activity scans showing a temporary decrease in the metabolic activity of large parts of the cerebral cortex with normal or increased metabolic activity in the limbic areas of the brain.

Health General

Orgasm, and sexual activity as a whole, are physical activities that can require exertion of many major bodily systems. A 1997 study in the BMJ based upon 918 men age 45–59 found that after a ten-year follow-up, men who had fewer orgasms were twice as likely to die of any cause as those having two or more orgasms a week. A follow-up in 2001 which focused more specifcally on cardiovascular health found that having sex three or more times a week was associated with a 50% reduction in the risk of heart attack or stroke. (Note that as a rule, correlation does not imply causation.)

Tere is some research suggesting that greater resting heart rate variability is associated with orgasms through penile-vaginal intercourse without additional simultaneous clitoral stimulation.

A small percentage of men have a disease called postorgasmic illness syndrome (POIS), which causes severe muscle pain throughout the body and other symptoms immediately following ejaculation. Te symptoms last for up to a week. Some doctors speculate that the frequency of POIS "in the population may be greater than has been reported in the academic literature", and that many POIS suﬀerers are undiagnosed.

Dysfunction and satisfaction Te inability to have orgasm, or regular diﬃculty reaching orgasm after ample sexual stimulation, is called anorgasmia or inorgasmia. If a male experiences erection and ejaculation but no orgasm, he is said to have sexual anhedonia (a condition in which an individual cannot feel pleasure from an orgasm) or ejaculatory anhedonia. Anorgasmia is signifcantly more common in women than in men, which has been attributed to the lack of sex education with regard to women's bodies, especially in sex-negative cultures, such as clitoral stimulation usually being key for women to orgasm.

Approximately 25% of women report diﬃculties with orgasm, 10% of women have never had an orgasm, and 40% or 40– 50% have either complained about sexual dissatisfaction or experienced diﬃculty becoming sexually aroused at some point in their lives. A 1994 study by Laumann et al. found that 75% of men and 29% of women always have orgasms with their partner. Women are much more likely to be nearly always or always orgasmic when alone than with a partner. However, in a 1996 study by Davis et al., 62% of women in a partnered relationship said they were satisfed with the frequency/consistency of their orgasms. Additionally, some women express that their most satisfying sexual experiences entail being connected to someone, rather than solely basing satisfaction on orgasm.

Kinsey's Sexual Behavior in the Human Female showed that, over the previous fve years of sexual activity, 78% of women had orgasms in 60% to 100% of sexual encounters with other women, compared with 55% for heterosexual sex. Kinsey attributed this diﬀerence to female partners knowing more about women's sexuality and how to optimize women's sexual satisfaction than male partners do. Like Kinsey, scholars such as Peplau, Fingerhut and Beals (2004) and Diamond (2006) found that lesbians have orgasms more often and more easily in sexual interactions than heterosexual women do, and that female partners are more likely to emphasize the emotional aspects of lovemaking. In contrast, research by Diane Holmberg and Karen L. Blair (2009), published in the Journal of Sex Research, found that women in same-sex relationships enjoyed identical sexual desire, sexual communication, sexual satisfaction, and satisfaction with orgasm as their heterosexual counterparts.

Specifcally in relation to simultaneous orgasm and similar practices, many sexologists claim that the problem of premature ejaculation is closely related to the idea encouraged by a scientifc approach in the early 20th century when mutual orgasm was overly emphasized as an objective and a sign of true sexual satisfaction in intimate relationships.

If orgasm is desired, anorgasmia may be attributed to an inability to relax. It may be associated with performance pressure and an unwillingness to pursue pleasure, as separate from the other person's satisfaction; often, women worry so much about the pleasure of their partner that they become anxious, which manifests as impatience with the delay of orgasm for them. Tis delay can lead to frustration of not reaching orgasmic sexual satisfaction. Psychoanalyst Wilhelm Reich, in his 1927 book Die Funktion des Orgasmus (published in English in 1980 as Genitality in the Teory and Terapy of Neurosis) was the frst to make orgasm central to the concept of mental health, and defned neurosis in terms of blocks to having orgastic potency. Although orgasm dysfunction can have psychological components, physiological factors often play a role. For instance, delayed orgasm or the inability to achieve orgasm is a common side eﬀect of many medications.

428 Menopause may involve loss of hormones supporting sexuality and genital functionality. Vaginal and clitoral atrophy and dryness aﬀects up to 50%–60% of postmenopausal women. Testosterone levels in men fall as they age. Sexual dysfunction overall becomes more likely with poor physical and emotional health. "Negative experiences in sexual relationships and overall well-being" are associated with sexual dysfunction.

Fertility Tere are theories that the female orgasm might increase fertility. For example, the 30% reduction in size of the vagina could help clench onto the penis (much like, or perhaps caused by, the pubococcygeus muscles), which would make it more stimulating for the male (thus ensuring faster or more voluminous ejaculation). Te British biologists Baker and Bellis have suggested that the female orgasm may have a peristalsis or "upsuck" action (similar to the esophagus' ability to swallow when upside down), resulting in the retaining of favorable sperm and making conception more likely. Tey posited a role of female orgasm in sperm competition.

Te observation that women tend to reach orgasm more easily when they are ovulating also suggests that it is tied to increasing fertility. Evolutionary biologist Robin Baker argues in Sperm Wars that occurrence and timing of orgasms are all a part of the female body's unconscious strategy to collect and retain sperm from more evolutionarily ft men.An orgasm during intercourse functions as a bypass button to a woman's natural cervical flter against sperm and pathogens. An orgasm before functions to strengthen the flter.

Desmond Morris proposed that orgasm might facilitate conception by exhausting the female and keeping her horizontal, thus preventing the sperm from leaking out. Tis possibility, sometimes called the "Poleaxe Hypothesis" or the "Knockout Hypothesis", is now considered highly doubtful. A 1994 Learning Channel documentary on sex had fber optic cameras inside the vagina of a woman while she had sexual intercourse. During her orgasm, her pelvic muscles contracted and her cervix repeatedly dipped into a pool of semen in the vaginal fornix, as if to ensure that sperm would proceed by the external orifce of the uterus, making conception more likely.

Evolutionary psychologists Christopher Ryan and Cacilda Jethá, in their discussion of the female orgasm, address how long it takes for females to achieve orgasm compared to males, and females' ability to have multiple orgasms, hypothesizing how especially well suited to multiple partners and insemination this is. Tey quote primate sexuality specialist Alan Dixson in saying that the monogamy-maintenance explanation for female orgasm "seems far-fetched" because "females of other primate species, and particularly those with multimale-multifemale [promiscuous] mating systems such as macaques and chimpanzees, exhibit orgasmic responses in the absence of such bonding or the formation of stable family units." On the other hand, Dixson states that "Gibbons, which are primarily monogamous, do not exhibit obvious signs of female orgasm."

Te female promiscuity explanation of female sexuality was echoed at least 12 years earlier by other evolutionary biologists, and there is increasing scientifc awareness of the female proceptive phase. Tough Dixson classifes humans as mildly polygynous in his survey of primate sexuality, he appears to have doubts, when he writes, "One might argue that ... the female's orgasm is rewarding, increases her willingness to copulate with a variety of males rather than one partner, and thus promotes sperm competition." Ryan and Jethá use this as evidence for their theory that partible paternity and promiscuity were common for early modern humans.

Adaptive or vestigial Te clitoris is homologous to the penis; that is, they both develop from the same embryonic structure. While researchers such as Geoffrey Miller, Helen Fisher, Meredith Small and Sarah Blaffer Hrdy "have viewed the clitoral orgasm as a legitimate adaptation in its own right, with major implications for female sexual behavior and sexual evolution," others, such as Donald Symons and Stephen Jay Gould, have asserted that the clitoris is vestigial or nonadaptive, and that the female orgasm serves no particular evolutionary function. However, Gould acknowledged that "most female orgasms emanate from a clitoral, rather than vaginal (or some other), site" and stated that his nonadaptive belief "has been widely misunderstood as a denial of either the adaptive value of female orgasm in general, or even as a claim that female orgasms lack signifcance in some broader sense". He explained that although he accepts that "clitoral orgasm plays a pleasurable and central role in female sexuality and its joys," "[a]ll these favorable attributes, however, emerge just as clearly and just as easily, whether the clitoral site of orgasm arose as a spandrel or an adaptation". He said that the "male biologists who fretted over [the adaptionist questions] simply assumed that a deeply vaginal site, nearer the region of fertilization, would offer greater selective beneft" due to their Darwinian, summum bonum beliefs about enhanced reproductive success.

Proponents of the nonadaptive hypothesis, such as Elisabeth Lloyd, refer to the relative diﬃculty of achieving female orgasm through vaginal sex, the limited evidence for increased fertility after orgasm and the lack of statistical correlation between the capacity of a woman to orgasm and the likelihood that she will engage in intercourse. "Lloyd is by no means against 429 evolutionary psychology. Quite the opposite; in her methods and in her writing, she advocates and demonstrates a commitment to the careful application of evolutionary theory to the study of human behavior," stated Meredith L. Chivers. She added that Lloyd "meticulously considers the theoretical and empirical bases for each account and ultimately concludes that there is little evidence to support an adaptionist account of female orgasm" and that Lloyd instead "views female orgasm as an ontogenetic leftover; women have orgasms because the urogenital neurophysiology for orgasm is so strongly selected for in males that this developmental blueprint gets expressed in females without aﬀecting ftness, just as males have nipples that serve no ftness-related function".

A 2005 twin study found that one in three women reported never or seldom achieving orgasm during sexual intercourse, and only one in ten always orgasmed. Tis variation in ability to orgasm, generally thought to be psychosocial, was found to be 34% to 45% genetic. Te study, examining 4000 women, was published in Biology Letters, a Royal Society journal. Elisabeth Lloyd has cited this as evidence for the notion that female orgasm is not adaptive.

Miller, Hrdy, Helen O'Connell and Natalie Angier have criticized the "female orgasm is vestigial" hypothesis as understating and devaluing the psychosocial value of the female orgasm.[9] Hrdy stated that the hypothesis smacks of sexism. O'Connell said, "It boils down to rivalry between the sexes: the idea that one sex is sexual and the other reproductive. Te truth is that both are sexual and both are reproductive." O'Connell used MRI technology to defne the true size and shape of the clitoris, suggesting that it extends into the anterior wall of the vagina (see above).

O'Connell describes typical textbook descriptions of the clitoris as lacking detail and including inaccuracies, saying that the work of Georg Ludwig Kobelt in the early 19th century provides a most comprehensive and accurate description of clitoral anatomy. She argues that the bulbs appear to be part of the clitoris and that the distal urethra and vagina are intimately related structures, although they are not erectile in character, forming a tissue cluster with the clitoris that appears to be the center of female sexual function and orgasm. By contrast, Nancy Tuana, at the 2002 conference for Canadian Society of Women in Philosophy, argues that the clitoris is unnecessary in reproduction, but that this is why it has been "historically ignored", mainly because of "a fear of pleasure. It is pleasure separated from reproduction. Tat's the fear". She reasoned that this fear is the cause of the ignorance that veils female sexuality.

Other theories Brody Costa et al. suggest that women's vaginal orgasm consistency is associated with being told in childhood or adolescence that the vagina is the important zone for inducing female orgasm. Other proposed factors include how well women focus mentally on vaginal sensations during penile-vaginal intercourse, the greater duration of intercourse, and preference for above-average penis length. Costa theorizes that vaginal orgasm is more prevalent among women with a prominent tubercle of the upper lip. His research indicates that "[a] prominent and sharply raised lip tubercle has been associated with greater odds (odds ratio = 12.3) of ever having a vaginal orgasm, and also with greater past month vaginal orgasm consistency (an eﬀect driven by the women who never had a vaginal orgasm), than less prominent lip tubercle categories." However, lip tubercle was not associated with social desirability responding, or with orgasm triggered by masturbation during penile- vaginal sex, solitary or partner clitoral or vaginal masturbation, vibrator, or cunnilingus.

An empirical study carried out in 2008 provides evidence for Freud's implied link between inability to have a vaginal orgasm and psychosexual immaturity. In the study, women reported their past month frequency of diﬀerent sexual behaviors and corresponding orgasm rates and completed the Defense Style Questionnaire (DSQ-40), which is associated with various psychopathologies. Te study concluded that a "vaginal orgasm was associated with less somatization, dissociation, displacement, autistic fantasy, devaluation, and isolation of aﬀect." Moreover, "vaginally anorgasmic women had immature defenses scores comparable to those of established (depression, social anxiety disorder, panic disorder, and obsessive– compulsive disorder) outpatient psychiatric groups." In the study, a vaginal orgasm (as opposed to a clitoral orgasm) was defned as being triggered solely by penile–vaginal intercourse. According to Wilhelm Reich, the lack of women's capacity to have a vaginal orgasm is due to a lack of orgastic potency, which he believed to be the result of culture's suppression of genital sexuality.

Tantric sex Tantric sex, which is not the same as Buddhist tantra (Vajrayana), is the ancient Indian spiritual tradition of sexual practices. It attributes a diﬀerent value to orgasm than traditional cultural approaches to sexuality. Some practitioners of tantric sex aim to eliminate orgasm from sexual intercourse by remaining for a long time in the pre-orgasmic and non-emission state. Advocates of this, such as Rajneesh, claim that it eventually causes orgasmic feelings to spread out to all of one's conscious experience.

Advocates of tantric and neotantric sex who claim that Western culture focuses too much on the goal of climactic orgasm, which reduces the ability to have intense pleasure during other moments of the sexual experience, suggest that eliminating this enables a richer, fuller and more intense connection.

430 Literature

Jupiter and Juno, by Annibale Carracci. Orgasm has been widely described in literature over the centuries. In antiquity, Latin literature addressed the subject as much as Greek literature: Book III of Ovid's Metamorphoses retells a discussion between Jove and Juno, in which the former states: "Te sense of pleasure in the male is far / More dull and dead, than what you females share." Juno rejects this thought; they agree to ask the opinion of Tiresias ("who had known Venus/Love in both ways," having lived seven years as a female). Tiresias oﬀends Juno by agreeing with Jove, and she strikes him blind on the spot (Jove lessens the blow by giving Tiresias the gift of foresight, and a long life). Earlier, in the Ars Amatoria, Ovid states that he abhors sexual intercourse that fails to complete both partners.

Te theme of orgasm survived during Romanticism and is incorporated in many homoerotic works. In FRAGMENT: Supposed to be an Epithalamium of Francis Ravaillac and Charlotte Cordé, Percy Bysshe Shelley (1792–1822), "a translator of extraordinary range and versatility", wrote the phrase "No life can equal such a death." Tat phrase has been seen as a metaphor for orgasm, and it was preceded by the rhythmic urgency of the previous lines "Suck on, suck on, I glow, I glow!", which has been seen as alluding to fellatio. For Shelley, orgasm was "the almost involuntary consequences of a state of abandonment in the society of a person of surpassing attractions". Edward Ellerker Williams, the last love of Shelley's life, was remembered by the poet in "Te Boat on the Serchio", which has been considered as possibly "the grandest portrayal of orgasm in literature":

Shelley, in this poem, associates orgasm with death when he writes "the death which lovers love". In French literature, the term la petite mort (the little death) is a famous euphemism for orgasm; it is the representation of man who forgets himself and the world during orgasm. Jorge Luis Borges, in the same vision, wrote in one of the several footnotes of "Tlön, Uqbar, Orbis Tertius" that one of the churches of Tlön claims Platonically that "All men, in the vertiginous moment of coitus, are the same man. All men who repeat a line from Shakespeare are William Shakespeare." Shakespeare himself was knowledgeable of this idea: lines "I will live in thy heart, die in thy lap, and be buried in thy eyes" and "I will die bravely, like a smug bridegroom", said respectively by Benedick in Much Ado About Nothing and by King Lear in the play of that ilk, are interpreted as "to die in a woman's lap" = "to experience a sexual orgasm". Sigmund Freud with his psychoanalytic projects, in Te Ego and the Id (1923), speculates that sexual satisfaction by orgasm make Eros ("life instinct") exhausted and leaves the feld open to Tanatos ("death instinct"), in other words, with orgasm Eros fulflls its mission and gives way to Tanatos. [165] Other modern authors have chosen to represent the orgasm without metaphors. In the novel Lady Chatterley's Lover (1928), by D. H. Lawrence, we can fnd an explicit narrative of a sexual act between a couple: "As he began to move, in the sudden helpless orgasm there awoke in her strange thrills rippling inside her..."[166]

Sexual Position

A sex position is a position of the body that an individual or couple people may use for sexual intercourse or other sexual activities. Sexual acts are generally described by the positions the participants adopt in order to perform those acts. Tough sexual intercourse generally involves penetration of the body of one person by another, sex positions commonly involve penetrative or non-penetrative sexual activities.

Tree categories of sexual intercourse are commonly practiced: vaginal intercourse (involving vaginal penetration), anal penetration, and oral sex (especially mouth-on-genital stimulation). Sex acts may also involve other forms of genital stimulation, such as solo or mutual masturbation, which may involve rubbing or penetration by the use of fngers or hands or by a device (sex toy), such as a dildo or vibrator. Te act may also involve anilingus. Tere are numerous sex positions that participants may adopt in any of these types of sexual intercourse or acts; some authors have argued that the number of sex positions is essentially limitless.

History Te earliest known European medieval text dedicated to sexual positions is the Speculum al foderi, sometimes known as "Te Mirror of Coitus" (or literally[according to whom?] "a mirror for fuckers"), a 15th-century Catalan text discovered in the 1970s.

Exclusively penetrative Tese positions involve the insertion of a phallic object(s) (such as a penis, strap-on dildo, plug, or other nonporous object(s)) into a vagina, anus or mouth.

Missionary, the most commonly used sex position Tondo of an Attic red-fgure kylix by the Triptolemos painter, ca. 470 BC, Tarquinia National Museum

431 A rear-penetration position, commonly referred to as 'doggy style'. Te receiving partner can be penetrated either vaginally or anally. Penetrating partner on top with front entry Te most used sex position is the missionary position. In this position, the participants face each other. Te receiving partner lies on their back with legs apart, while the penetrating partner lies on top. Tis position and the following variations may be used for vaginal or anal intercourse.

Te penetrating partner stands in front of the receiving partner, whose legs dangle over the edge of a bed or some other platform like a table. With the receiving partner's legs lifted towards the ceiling and resting against the penetrating partner, this is sometimes called the butterfy position. Tis can also be done as a kneeling position. Te receiving partner lies on their back. Te penetrating partner stands and lifts the receiving partner's pelvis for penetration. A variant is for the receiving partner to rest their legs on the penetrating partner's shoulders.

Te receiving partner lies on their back, legs pulled up straight and knees near to the head. Te penetrating partner holds the receiving partner's legs and penetrates from above. Similarly to the previous position, but the receiving partner's legs need not be straight and the penetrating partner wraps their arms around the receiving partner to push the legs as close as possible to the chest. Called the stopperage in Burton's translation of Te Perfumed Garden.

Te coital alignment technique, a position where a woman is vaginally penetrated by a man, and the penetrating partner moves upward along the woman's body until the penis is pointing down, the dorsal side of the penis now rubbing against the clitoris.

Te receiving partner crosses their feet behind their head (or at least puts their feet next to their ears), while lying on their back. Te penetrating partner then holds the receiving partner tightly around each instep or ankle and lies on the receiving partner full-length. A variation is to have the receiving partner cross their ankles on their stomach, knees to shoulders, and then have the penetrating partner lie on the receiving partner's crossed ankles with their full weight. Called the Viennese oyster by Te Joy of Sex. Penetrating from behind

1st century AD depiction of 'spooning' Most of these positions can be used for either vaginal or anal penetration. Variants of the doggy style or doggy position include:

Te receiving partner is on all fours with their torso horizontal and the penetrating partner inserts either their penis or sex toy into either the vagina or anus from behind. Te receiving partner's torso is angled downwards and the penetrating partner raises their own hips above those of the receiving partner for maximum penetration.

Te penetrating partner places their feet on each side of the receiving partner while keeping their knees bent and eﬀectively raising up as high as possible while maintaining penetration. Te penetrating partner's hands usually have to be placed on the receiving partner's back to keep from falling forward. Te receiving partner kneels upright while the penetrating partner gently pulls the receiving partner's arms backwards at the wrists towards them. In the spoons position both partners lie on their side, facing the same direction. Variants of this technique include the following:

Te receiving partner lies on their side. Te penetrating partner kneels and penetrates from behind. Alternatively, the penetrating partner can stand if the receiving partner is on a raised surface. Te receiving partner lies facing down, possibly with their legs spread. Te penetrating partner lies on top of them. Te placement of a pillow beneath the receiving partner's hips can help increase stimulation in this position.

Te receiving partner lies face down, knees together. Te penetrating partner lies on top with spread legs. Te receiving partner lies on their side with their uppermost leg forward. Te penetrating partner kneels astride the receiver's lowermost leg.

Woman on top position in the Kama Sutra Receiving partner on top See also: Woman on top

432 Te 'cowgirl' position Most of these positions can be used for either vaginal or anal penetration. When the receiving partner is a woman, these positions are sometimes called the woman on top, cowboy or cowgirl positions.

A feature of these positions is that the penetrating partner lies on their back with the receiving partner on top:

Te receiving partner can kneel while straddling the penetrating partner, with the participants facing each other. Alternatively, the receiving partner can face away from the penetrating partner. Tis position is sometimes called the reverse cowboy or reverse cowgirl position. Te receiving partner can arch back with hands on the ground. Te receiving partner can squat (instead of kneel) facing the penetrating partner. Te receiving partner can bring forward their knees against the ground. Te penetrating partner lies with their upper back on a low table, couch, chair or edge of bed, keeping their feet fat on the foor and back parallel to foor. Te receiving partner straddles them, also keeping their feet on the foor. Receiving partner can assume any of various positions. Te lateral coital position was recommended by Masters and Johnson, and was preferred by three quarters of their heterosexual study participants after having tried it. Te position involves the male on his back, with the female rolled slightly to the side so that her pelvis is atop his, but her weight is beside his. Tis position can also be used for anal penetration, and is not limited to heterosexual partners.

A couple performing sexual intercourse from a seated position Sitting and kneeling Most of these positions can be used for either vaginal or anal penetration.

Te penetrating partner sits on an area surface, legs outstretched. Te receiving partner sits on top and wraps their legs around the penetrating partner. Called pounding on the spot in the Burton translation of Te Perfumed Garden. If the penetrating partner sits cross-legged, it is called the lotus position or lotus fower. Te position can be combined with fondling of erogenous zones. Te penetrating partner sits in a chair. Te receiving partner straddles penetrating partner and sits, facing the penetrating partner, feet on foor. Tis is sometimes called a lap dance, which is somewhat erroneous as a lap dance typically does not involve penetration. Te receiving partner may also sit in reverse, with their back to the penetrating partner.

Te penetrating partner sits on a couch or in a chair that has armrests. Te receiving partner sits in the penetrating partner's lap, perpendicular to penetrating partner, with their back against the armrest. Te penetrating partner kneels while the receiving partner lies on their back, ankles on each side of penetrating partner's shoulders.

One partner stands while holding up the other without a support Standing Most of these positions can be used for either vaginal or anal penetration. In the basic standing position, both partners stand facing each other. Te following variations are possible:

In the basic standing position, both partners stand facing each other and engage in vaginal sex. In order to match heights, the shorter partner can, for instance, stand on a stair or wear high heels. It may be easier to maintain solid thrusts if the woman has her back to a wall. With such a support, the Kama Sutra calls this position the Suspended Congress. Tis position is most often used in upright places, such as a wall in a bedroom or a shower. Te penetrating partner stands, and the receiving partner wraps their arms around his neck, and their legs around his waist, thereby exposing either the vagina or anus to the man's penis. Tis position is made easier with the use of a solid object behind the receiver, as above. To assume this position, it can be easier to start with the receiving partner laying on their back on the edge of a bed; the penetrating partner puts his elbows under their knees, enters them, and then lifts them as he rises to a standing position. In Japan, this is colloquially called the Ekiben position, after a specifc bento lunch box sold at train stations.

Alternatively, the receiving partner can face away from the penetrating partner which allows for anal sex. Tis position is varied by having the receiving partner assume diﬀerent semi-standing positions. For instance, they may bend at the waist, resting their hands or elbows on a table. Anal sex positions

19th century depiction of anal penetration; detail of a painting by Paul Avril Tese positions involve anal penetration:

433 Doggy style penetration maximizes the depth of penetration, but can pose the risk of pushing against the sigmoid colon. If the receiving partner is male, this increases the chances of stimulating the prostate. Te penetrating partner controls the thrusting rhythm. A variation is the leapfrog position, in which the receiving partner angles their torso downward. Te receiving partner may also lie fat and face down, with the penetrating partner straddling their thighs.

Anal sex between two men in the missionary position In the missionary positions, to achieve optimal alignment, the receiving partner's legs should be in the air with the knees drawn towards their chest. Some sort of support (such as a pillow) under the receiving partner's hips can also be useful. Te penetrating partner positions themselves between the receiving partner's legs. Te penetrating partner controls the thrusting rhythm. Tis position is often cited as good for beginners, because it allows them to relax more fully than is usual in the doggy style position. Te spoons position allows the receiving partner to control initial penetration and the depth, speed and force of subsequent thrusting. Te receiving partner on top positions allow the receiving partner more control over the depth, rhythm and speed of penetration. More specifcally, the receiving partner can slowly push their anus down on the penetrating partner, allowing time for their muscles to relax. Less common positions

Te T-square position Tese positions are more innovative, and perhaps not as widely known or practiced as the ones listed above.

Te receiving partner lies on their back with knees up and legs apart. Te penetrating partner lies on their side perpendicular to the receiver, with the penetrating partner's hips under the arch formed by receiver's legs. Tis position is sometimes called the T-square. Te receiving partner's legs are together turning to one side while looking up towards the penetrator, who has spread legs and is kneeling straight behind the other's hips. Te penetrator's hands are on the other's hips. Tis position can be called the modifed T-square.

Te Seventh Posture of Burton's translation of Te Perfumed Garden is an unusual position not described in other classical sex manuals. Te receiving partner lies on their side. Te penetrating partner faces the receiver, straddling the receiver's lower leg, and lifts the receiver's upper leg on either side of the body onto the crook of penetrating partner's elbow or onto the shoulder. While some references describe this position as being "for acrobats and not to be taken seriously”, others have found it very comfortable, especially during pregnancy. Te piledriver is a diﬃcult position sometimes seen in porn videos. It is described in many ways by diﬀerent sources. In a heterosexual context, the woman lies on her back, then raises her hips as high as possible, so that her partner, standing, can enter her vaginally or anally. Te position places considerable strain on the woman's neck, so frm cushions should be used to support her. Te receiver lies face down legs spread on the edge of the bed and parallel to the foor, while the penetrator stands behind, holding both legs. Te rusty bike pump is similar to a piledriver where penetration is achieved from above at a downward angle with the receiving partner bottom side up. Others Te receiving partner is on the bottom. Te penetrating partner lies on top perpendicularly to them. Te penetrating partner lies on their back, legs spread. Te receiving partner is on their back on top of the penetrator, legs spread, facing the opposite direction. Te penetrator and the receiver lie on their backs, heads pointed away from one another. Each places one leg on the other's shoulder (as a brace) and the other leg out somewhat to the side. Te receiving partner lies on their back with the penetrating partner lying perpendicular. Te receiving partner bends the knee closest to the penetrating partner's head enough so that there is room for the penetrating partner's waist to ft beneath it, while the penetrating partner's legs straddle the receiving partner's other leg. Te in-and-out thrusting action will move more along a side-to-side rather than top-to-bottom axis. Tis is sometimes called the scissors position. Tis position allows for breast stimulation during sex, for partners to maintain eye contact if they wish, and for a good view of both partners as they reach orgasm. Te penetrating partner sits on edge of a bed or chair with feet spread wide on foor. Te receiving partner lies on their back on the foor and drapes their legs and thighs over the legs of the penetrating partner. Te penetrating partner holds the knees of the receiving partner and controls thrusts. Using furniture or special apparatus Most sex acts are typically performed on a bed or other simple platform. As the range of supports available increases, so does the range of positions that are possible. Ordinary furniture can be used for this purpose. Also, various forms of erotic furniture and other apparatus such as fsting slings and trapezes have been used to facilitate even more exotic sexual positions.

434 Positions to promote or prevent conception See also: Birth control § Misconceptions Pregnancy is a potential result of any form of sexual activity where sperm comes in contact with the vagina; this is typically during vaginal sex, but pregnancy can result from anal sex, digital sex (fngering), oral sex, or by another body part, if sperm is transferred from one area to the vagina between a fertile female and a fertile male. Men and women are typically fertile during puberty. Tough certain sexual positions are believed to produce more favorable results than others, none of these are eﬀective means of contraception.

Positions during pregnancy Te goal is to prevent excessive pressure on the belly and to restrict penetration as required by the particular partners. Some of the positions below are popular positions for sex during pregnancy.

Woman on top: takes the pressure oﬀ of the woman's abdomen and allows her to control the depth and frequency of thrusting. Woman on back: like the missionary, but with less pressure on abdomen or uterus. Te woman lies on her back and raises her knees up towards her chest. Te partner kneels between her legs and enters from the front. A pillow is placed under her bottom for added comfort. Sideways: also keeps pressure oﬀ of her abdomen while supporting her uterus at the same time. Spooning: very popular positions to use during the late stages of pregnancy; allowing only shallow penetration and relieves the pressure on the stomach. Sitting: she mounts the sitting partner, relieving her stomach of pressure. From behind: allowing her to support stomach and breasts. Non-exclusively penetrative

Oral sex positions Oral sex is genital stimulation by the mouth. It may be penetrative or non-penetrative, and may take place before, during, as, or following intercourse. It may also be performed simultaneously (for example, when one partner performs cunnilingus, while the other partner performs fellatio), or only one partner may perform upon the other; this creates a multitude of variations.

Modern drawing of fellatio A late 19th-century Beijing hand scroll depicting fellatio

19th-century depiction of cunnilingus (detail) by Paul Avril Fellatio Fellatio is oral sex performed on a penis. Possible positions include:

Sitting Te receiver lies on his back while the partner kneels between his legs. Te receiver lies on his back while the partner lies oﬀ to the side of their legs. Te receiver sits in a chair the partner kneels in front of them between their legs. Standing Te receiver stands while the partner either kneels in front of them or sits (in a chair or on the edge of a bed, etc.) and bends forward. Te receiver stands while the partner, also standing, bends forward at the waist. Te receiver stands or crouches at the edge of the bed, facing the bed. Te active partner lies on the bed with their head hanging over the edge of the bed backward. Te receiver inserts their penis into the partner's mouth, usually to achieve deep throat penetration. Lying While the active partner lies on their back, the receiver assumes the missionary position but adjusted forward. Te active partner (with breasts) lies on their back, and the receiver inserts their penis between the breasts, and into the mouth. Cunnilingus Cunnilingus is oral sex performed on the vulva and vagina. Possible positions include:

Te receiver lies on her back as in the missionary position. Te active partner lies on their front between their legs. Te active partner sits. Te receiver stands facing away and bends at the hips. Te active partner sits. Te receiver stands or squats facing towards partner and may arch her back, to create further stimulation. Te active partner lies on their back while the receiver kneels with their legs at their sides and their genitals on their mouth. In other words, the receiver sits on the face of her partner. Te receiver rests on all fours as in the doggy style position. Te partner lies on their back with his head under their genitalia.

435 Teir feet may commonly extend off the bed and rest on the foor. Te receiver services their own genitals. Although rarer, some people still fnd this possible[citation needed]; see autofellatio. Te receiver stands, possibly bracing themself against a wall. Te active partner kneels in front of them. Te receiver sits on the bed with her their open, the active partner kneels in front of them. Te receiver is upside-down (standing on hands, held by partner, or using support, such as bondage or furniture), with the active partner standing or kneeling (depending on elevation) in front or behind. Such a position may be difficult to achieve, or maintain for extended time periods, but the rush of blood to the brain can alter stimulation's effect. Te receiver stands on hands, resting each leg on either side of the active partner's head, with the active partner standing or kneeling facing them. Depending on which way up the receiver is facing, different stimulation and levels of comfort may be available. Sixty-nine

Te 69 position Simultaneous oral sex between two people is called 69. Partners may be female or male. Tey can lie side-by-side, lie one on top of the other, or stand with one partner holding the other upside down.

Anilingus

Woman performing anilingus on another woman Positions for anilingus, also known as butt licking, rimming, anal-oral sex, rimjob, or tossing the salad, are often variants on those for genital-oral sex. Anilingus can be performed in a number of sex positions including:

Te passive partner is on all fours in the doggy position with the active partner behind. Te passive partner is on their back in the missionary position with their legs up. Te passive partner on top in the 69 position. Te rusty trombone, in which a male stands while the active partner performs both anilingus from behind, generally from a kneeling position, and also performs masturbation on the standing partner, thus somewhat resembling someone playing the trombone.

Other positions Fingering of the vulva, vagina or anus. Shocker: simultaneous fngering of the vagina and anus using one hand. Te index and middle fnger are inserted in the vagina, and the pinky in the anus. A number of variations are possible by using diﬀerent combinations of fngers in each orifce. Tis act fgures prominently in the Story of O: shortly after O's arrival at the Chateau, a man grabs her in this way. O is shocked, but she learns to accept this and ruder intrusions. Sometimes colloquially referred to as "Two in the pink, one in the stink." Fisting: inserting the entire hand into the vagina or anus. Tis usually requires large amounts of lubricant and relaxation. Te hand is usually not actually made into a fst, but instead the thumb is placed between the middle and ring fngers. Fisting can cause laceration or perforation of the vagina, perineum, rectum, or colon, resulting in serious injury and even death. Non-penetrative Main article: Non-penetrative sex

Drawing by Franz von Bayros showing an act of fngering Non-penetrative sex or frottage is generally sexual activity that excludes penetration, and often includes rubbing one's genitals on one's sexual partner. Tis may include the partner's genitals or buttocks, and can involve diﬀerent sex positions. As part of foreplay or to avoid penetrative sex, people engage in a variety of non-penetrative sexual behavior, which may or may not lead to orgasm.

Mutual masturbation: Te manual stimulation of the penis or scrotum in males and the clitoris or entire vulva in females. Partners simultaneously stimulating each other's genitals by mutual or simultaneous masturbation, rhythmic inter-genital contact friction or actual penetrative intercourse can lead to orgasm in one partner or the other (or sometimes simultaneously in both). Dry humping: frottage while clothed. Tis act is common, although not essential, in the dance style known as "grinding".

Handjob or fngering: Manual stimulation of a partner's penis, scrotum, clitoris or entire vulva. Known as "wanking" in the UK, and "fapping" in modern colloquial terms. Footjob: using the feet to stimulate the penis. Mammary intercourse: using the breasts together to stimulate the penis through the cleavage. (Should not be confused with a "boob job" meaning to have augmentive surgery done on the breasts.) Also called a titjob, titty-fucking, a tit-wank; several other slang terms exist.

436 Axillary intercourse: with the penis in the armpit. Commonly known as "bagpiping". Orgasm control: By self or by a partner managing the physical stimulation and sensation connected with the emotional and physiologic excitement levels. Trough the practice of masturbation an individual can learn to develop control of their own body's orgasmic response and timing. In partnered stimulation either partner can control their own orgasmic response and timing. With mutual agreement either partner can similarly learn to control or enhance their partner's orgasmic response and timing. Partner stimulation orgasm techniques referred to as expanded orgasm, extended orgasm or orgasm control can be learned and practiced for either partner to refne their control of the orgasmic response of the other. Partners mutually choose which is in control or in response to the other.

Orgasmic meditation, is a mindfulness practice where the object of meditation is conscious fnger to genital contact. "OMing" is practiced in pairs, with one partner, gently holding the genitals with both hands, and that partner's index fnger gently, precisely, slowly stroking the female’s clitoris specifcally and with both parties placing their complete awareness mindfully on that localized point of contact between them. Both practitioners focus their fullest attention on their sensitive nerve endings and on their fnest muscle control in stroking movement to develop connective (limbic) resonance between practitioners. Te outcome, is not simply orgasm but interpersonal connection. Te slang term humping may refer to masturbation—thrusting one's genitals against the surface of non-sexual objects, clothed or unclothed; or it may refer to penetrative sex.

Genital-genital rubbing Main articles: Intercrural sex, Frot, and Tribadism Genital-genital rubbing (often termed GG rubbing by primatologists to describe the behavior among female bonobos) is the sexual act of mutually rubbing genitals; it is sometimes grouped with frottage, but other terms, such as non-penetrative sex or outercourse, are also used:

Intercrural sex, or interfemoral sex: the penis is placed between the partner's thighs, perhaps rubbing the vulva, scrotum or perineum. Frot or frottage: two males mutually rubbing penises together. Tribadism or tribbing: two females mutually rubbing vulvae together. Docking: mutual masturbation by inserting the glans penis into the foreskin of another penis.

Group sex Depiction of a 'spit roast' on the rim of an Attic red-fgure kylix, c. 510 BC 19th-century depiction of a "sandwich" by Paul Avril

A double penetration Various people of gender and orientation may participate in group sex. While group sex does not imply that all participants must be in sexual contact with all others simultaneously, some positions are only possible with three or more people.

As with the positions listed above, more group sex positions become practical if erotic furniture is used.

Treesomes Main article: Treesome When three people have sex with each other, it is called a threesome. Possible ways of having all partners in sexual contact with each include some of the following:

One person performs oral sex on one partner while they engage in receptive anal or vaginal intercourse with the other partner. Sometimes called a spit roast. Also a good Basting. Te 369 position is where two people engage in oral sex in the 69 position while a third person positions himself to penetrate one of the others; usually a man engaging in sex doggie-style with the woman on top in the 69 position.

A man has vaginal or anal sex with one partner, while himself being anally penetrated by another (possibly with a strap-on dildo). Tree partners lie or stand in parallel, with one between the other two. Sometimes called a sandwich. Tis term may specifcally refer to the double penetration of a woman, with one penis in her anus, and the other in her vagina or of a male, with two penises in his anus. Two participants have vaginal/anal sex with each other, and one/both perform oral sex on a third. Tree people perform oral/vaginal/anal sex on one another simultaneously, commonly called a daisy chain. Te slang term lucky Pierre is sometimes used in reference to the person playing the middle role in a threesome, being anally penetrated while engaging in penetrative anal or vaginal sex. Foursomes A 469 is a four-person sexual position where two individuals engage in 69 oral sex while a third and a fourth person both

437 position themselves on each end to penetrate the two engaged in simultaneous oral sex; similar to a 369, with the addition of a fourth person. With many participants

Tese positions can be expanded to accommodate any number of participants:

A group of males masturbating is called a circle jerk. A group of males masturbating and ejaculating on one person's face is known as bukkake. A group of men, women, or both, each performing oral, anal or vaginal sex on the next, is called a daisy chain. When one woman or man is given the serial or parallel attention of many, often involving a queue (pulling a train), it is often termed a gangbang. Multiple penetration

Wikimedia Commons has media related to Multiple penetration. A person may be sexually penetrated multiple times simultaneously. Penetration may involve use of fngers, toes, sex toys, or penises. Scenes of multiple penetration are common in pornography.

If one person is penetrated by two objects, it is generically called double penetration (DP). Double penetration of the vagina, anus, or mouth can involve:

Simultaneous penetration of the anus by two penises or other objects. Tis is commonly called double anal penetration (DAP) or double stuffing. Simultaneous penetration of the vagina by two penises or other objects. Tis is commonly called double vaginal penetration (DVP) or double stuffing. Simultaneous penetration of the vagina and anus. If this is done using penises and/or strap-on dildos, this is sometimes called the sandwich or BigMac. Te shocker (see above) accomplishes this using several fngers of one hand. Simultaneous penetration of the mouth and either the vagina or anus. If the penetrating objects are penises, this is sometimes called the spit roast, the Chinese fnger trap, or the Eiffel tower.

Number of positions, and effects on physical abilities Sex manuals usually present a guide to sex positions. Sex manuals have a long history. In the Graeco-Roman era, a sex manual was written by Philaenis of Samos, possibly a hetaira (courtesan) of the Hellenistic period (3rd–1st century BC).[43] Te Kama Sutra of Vatsyayana, believed to have been written in the 1st to 6th centuries, has a notorious reputation as a sex manual. Different sex positions result in differences in the depth of sexual penetration and the angle of penetration. Many attempts have been made to categorize sex positions. Alfred Kinsey categorized six primary positions, Alex Comfort categorized more than 600 and Gershon Legman categorized 3,780. However, the suggestion that the number of positions that can be used for sex is essentially limitless also exists.

Some people are limited by physical disabilities in the sex positions which they may use without pain or other discomfort. Other physical limitations of one or both participants also limit the sex positions which they may adopt. For example, the spoons position is recommended when either partner has back problems; the starfsh position is recommended to achieve orgasms more easily and the missionary position may be uncomfortable for the receiving partner if the weight of the inserting partner, relative to the receiving partner's, is a problem. Also, the standing positions may be unsuitable if there is a signifcant height diﬀerence between the participants, unless the female is being carried.

Orgy

In modern usage, an orgy is a sex party where guests freely engage in open and unrestrained sexual activity or group sex.

Swingers' parties do not always conform to this designation because at many swinger parties the sexual partners may all know each other or at least have some commonality among economic class, educational attainment or other shared attributes. Some swingers contend that an orgy, as opposed to a sex party, requires some anonymity of sexual partners in complete sexual abandon. Other kinds of "sex party" may fare less well with this labeling.

Participation in an "orgy" is a common sexual fantasy and group sex targeting such consumers is a subgenre in pornographic flms.

Te term is also used metaphorically in expressions, such as an "orgy of colour" or an "orgy of destruction" to indicate excess, overabundance. Te term "orgiastic" does not generally connote group sex and is closer to the classical roots and this metaphorical usage.

438 In ancient Greek religion, orgia (ὄργια, sing. ὄργιον, orgion) were ecstatic rites characteristic of the Greek and Hellenistic mystery religions. Unlike public religion, or the private religious practices of a household, the mysteries were open only to initiates, and were thus "secret". Some rites were held at night. Orgia were part of the Eleusinian Mysteries, the Dionysian Mysteries, and the cult of Cybele, which involved the castration of her priests in a frenzied trance. Because of their secret, nocturnal, and unscripted nature, the orgia were subject to prurient speculation and regarded with suspicion, particularly by the Romans, who attempted to suppress the Bacchanals in 186 BC. Orgia are popularly thought to have involved sex, but, while sexuality and fertility were cultic concerns, the primary goal of the orgia was to achieve an ecstatic union with the divine.

19) Nature, and Environment

Earth's axis of rotation is tilted with respect to its orbital plane, producing seasons on Earth. Te gravitational interaction between Earth and the Moon causes ocean tides, stabilizes Earth's orientation on its axis, and gradually slows its rotation. [28] Earth is the densest planet in the Solar System and the largest of the four terrestrial planets.[29]

Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water, mostly by oceans.[30] Te remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. Te majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the Earth's magnetic feld, and a convecting mantle that drives plate tectonics.

Shape

Shown are distances between surface relief and the geocentre. Te South American Andes summits are visible as elevated areas. Data from the Earth2014[91] global relief model. Main articles: Figure of the Earth, Earth radius, and Earth's circumference Te shape of Earth is approximately oblate spheroidal. Due to rotation, the Earth is fattened at the poles and bulging around the equator.[92] Te diameter of the Earth at the equator is 43 kilometres (27 mi) larger than the pole-to-pole diameter.[93] Tus the point on the surface farthest from Earth's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador (6,384.4 km (3,967.1 mi)).[94][95][96][97] Te average diameter of the reference spheroid is 12,742 kilometres (7,918 mi). Local topography deviates from this idealized spheroid, although on a global scale these deviations are small compared to Earth's radius: Te maximum deviation of only 0.17% is at the Mariana Trench (10,911 metres (35,797 ft) below local sea level), whereas Mount Everest (8,848 metres (29,029 ft) above local sea level) represents a deviation of 0.14%.[n 13]

439 In geodesy, the exact shape that Earth's oceans would adopt in the absence of land and perturbations such as tides and winds is called the geoid. More precisely, the geoid is the surface of gravitational equipotential at mean sea level.

Earth's mass is approximately 5.97×1024 kg (5,970 Yg). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements.

Te most common rock constituents of the crust are nearly all oxides: chlorine, sulfur, and fuorine are the important exceptions to this and their total amount in any rock is usually much less than 1%. Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash and soda.

Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical (rheological) properties. Te outer layer is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. Te crust is separated from the mantle by the Mohorovičić discontinuity. Te thickness of the crust varies from about 6 kilometres (3.7 mi) under the oceans to 30–50 km (19–31 mi) for the continents. Te crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, and it is of the lithosphere that the tectonic plates are composed. Beneath the lithosphere is the asthenosphere, a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at 410 and 660 km (250 and 410 mi) below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core.[104] Te Earth's inner core might rotate at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year.[105] Te radius of the inner core is about one ffth of that of Earth.

Nature, in the broadest sense, is the natural, physical, or material world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. Te study of nature is a large part of science. Although humans are part of nature, human activity is often understood as a separate category from other natural phenomena.

Te word nature is derived from the Latin word natura, or "essential qualities, innate disposition", and in ancient times, literally meant "birth". Natura is a Latin translation of the Greek word physis (φύσις), which originally related to the intrinsic characteristics that plants, animals, and other features of the world develop of their own accord. Te concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word φύσις by pre-Socratic philosophers, and has steadily gained currency ever since. Tis usage continued during the advent of modern scientifc method in the last several centuries.

Within the various uses of the word today, "nature" often refers to geology and wildlife. Nature can refer to the general realm of living plants and animals, and in some cases to the processes associated with inanimate objects–the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth. It is often taken to mean the "natural environment" or wilderness–wild animals, rocks, forest, and in general those things that have not been substantially altered by human intervention, or which persist despite human intervention. For example, manufactured objects and human interaction generally are not considered part of nature, unless qualifed as, for example, "human nature" or "the whole of nature". Tis more traditional concept of natural things which can still be found today implies a distinction between the natural and the artifcial, with the artifcial being understood as that which has been brought into being by a human consciousness or a human mind. Depending on the particular context, the term "natural" might also be distinguished from the unnatural or the supernatural.

Te four calendar seasons, depicted in an ancient Roman mosaic from Tunisia. In some parts of the world, some other "seasons" capture the timing of important ecological events such as hurricane season, tornado season, and wildfre season. [citation needed] Te most historically important of these are the three seasons—food, growth, and low water—which were previously defned by the former annual fooding of the Nile in Egypt.

Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualifcation, "weather" is generally understood to mean the weather of Earth. 440 Weather is driven by air pressure, temperature and moisture differences between one place and another. Tese differences can occur due to the sun's angle at any particular spot, which varies with latitude. Te strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley Cell, the Ferrel Cell, the Polar Cell, and the jet stream. Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream fow. Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (−40 °F to 100 °F) annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by the Earth, thus infuencing long- term climate and global climate change.

Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Te Earth's weather system is a chaotic system; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modifed weather patterns.

Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. Te movement of mass ejected from the Sun is known as the solar wind.

A natural disaster is a major adverse event resulting from natural processes of the Earth; examples include foods, hurricanes, tornadoes, volcanic eruptions, earthquakes, tsunamis, and other geologic processes. A natural disaster can cause loss of life or property damage, and typically leaves some economic damage in its wake, the severity of which depends on the aﬀected population's resilience, or ability to recover and also on the infrastructure available.

An adverse event will not rise to the level of a disaster if it occurs in an area without vulnerable population. In a vulnerable area, however, such as Nepal during the 2015 earthquake, an earthquake can have disastrous consequences and leave lasting damage, which can require years to repair.

Geography (from Greek γεωγραφία, geographia, literally "earth description") is a feld of science devoted to the study of the lands, the features, the inhabitants, and the phenomena of Earth. Te frst person to use the word "γεωγραφία" was Eratosthenes (276–194 BC). Geography is an all- encompassing discipline that seeks an understanding of the Earth and its human and natural complexities—not merely where objects are, but how they have changed and come to be.

Geography is often defned in terms of the two branches of human geography and physical geography. Human geography deals with the study of people and their communities, cultures, economies and interactions with the environment by studying their relations with and across space and place. Physical geography deals with the study of processes and patterns in the natural environment like the atmosphere, hydrosphere, biosphere, and geosphere.

Te four historical traditions in geographical research are: spatial analyses of natural and the human phenomena, area studies of places and regions, studies of human-land relationships, and the Earth sciences. Geography has been called "the world discipline" and "the bridge between the human and the physical sciences”.

Physical geography (also known as geosystems or physiography) is one of the two major sub-felds of geography. Physical geography is that branch of natural science which deals with the study of processes and patterns in the natural environment like the atmosphere, hydrosphere, biosphere, and geosphere, as opposed to the cultural or built environment, the domain of human geography.

Geomorphology (from Ancient Greek: γῆ, gê, "earth"; μορφή, morphḗ, "form"; and λόγος, lógos, "study") is the scientifc study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near the Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform history and dynamics and to predict changes through a combination of feld observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology and geotechnical engineering. Tis broad base of interests contributes to many research styles and interests within the feld.

441 Te study of landforms and the evolution of the Earth's surface can be dated back to scholars of Classical Greece. Herodotus argued from observations of soils that the Nile delta was actively growing into the Mediterranean Sea, and estimated its age. [9] Aristotle speculated that due to sediment transport into the sea, eventually those seas would fll while the land lowered. He claimed that this would mean that land and water would eventually swap places, whereupon the process would begin again in an endless cycle.

Another early theory of geomorphology was devised by the polymath Chinese scientist and statesman Shen Kuo (1031–1095 AD). Tis was based on his observation of marine fossil shells in a geological stratum of a mountain hundreds of miles from the Pacifc Ocean. Noticing bivalve shells running in a horizontal span along the cut section of a cliﬀside, he theorized that the cliﬀ was once the pre-historic location of a seashore that had shifted hundreds of miles over the centuries. He inferred that the land was reshaped and formed by soil erosion of the mountains and by deposition of silt, after observing strange natural erosions of the Taihang Mountains and the Yandang Mountain near Wenzhou. Furthermore, he promoted the theory of gradual climate change over centuries of time once ancient petrifed bamboos were found to be preserved underground in the dry, northern climate zone of Yanzhou, which is now modern day Yan'an, Shaanxi province.

Te term geomorphology seems to have been frst used by Laumann in an 1858 work written in German. Keith Tinkler has suggested that the word came into general use in English, German and French after John Wesley Powell and W. J. McGee used it during the International Geological Conference of 1891. John Edward Marr in his Te Scientifc Study of Scenery considered his book as, 'an Introductory Treatise on Geomorphology, a subject which has sprung from the union of Geology and Geography'.

An early popular geomorphic model was the geographical cycle or cycle of erosion model of broad-scale landscape evolution developed by William Morris Davis between 1884 and 1899. It was an elaboration of the uniformitarianism theory that had frst been proposed by James Hutton (1726–1797). With regard to valley forms, for example, uniformitarianism posited a sequence in which a river runs through a fat terrain, gradually carving an increasingly deep valley, until the side valleys eventually erode, fattening the terrain again, though at a lower elevation. It was thought that tectonic uplift could then start the cycle over. In the decades following Davis's development of this idea, many of those studying geomorphology sought to ft their fndings into this framework, known today as "Davisian". Davis's ideas are of historical importance, but have been largely superseded today, mainly due to their lack of predictive power and qualitative nature.

In the 1920s, Walther Penck developed an alternative model to Davis's. Penck thought that landform evolution was better described as an alternation between ongoing processes of uplift and denudation, as opposed to Davis's model of a single uplift followed by decay. He also emphasised that in many landscapes slope evolution occurs by backwearing of rocks, not by Davisian-style surface lowering, and his science tended to emphasise surface process over understanding in detail the surface history of a given locality. Penck was German, and during his lifetime his ideas were at times rejected vigorously by the English-speaking geomorphology community. His early death, Davis' dislike for his work, and his at-times-confusing writing style likely all contributed to this rejection.

Both Davis and Penck were trying to place the study of the evolution of the Earth's surface on a more generalized, globally relevant footing than it had been previously. In the early 19th century, authors – especially in Europe – had tended to attribute the form of landscapes to local climate, and in particular to the specifc effects of glaciation and periglacial processes. In contrast, both Davis and Penck were seeking to emphasize the importance of evolution of landscapes through time and the generality of the Earth's surface processes across different landscapes under different conditions.

During the early 1900s, the study of regional-scale geomorphology was termed "physiography". Physiography later was considered to be a contraction of "physical" and "geography", and therefore synonymous with physical geography, and the concept became embroiled in controversy surrounding the appropriate concerns of that discipline. Some geomorphologists held to a geological basis for physiography and emphasized a concept of physiographic regions while a conficting trend among geographers was to equate physiography with "pure morphology", separated from its geological heritage.[citation needed] In the period following World War II, the emergence of process, climatic, and quantitative studies led to a preference by many earth scientists for the term "geomorphology" in order to suggest an analytical approach to landscapes rather than a descriptive one.

Topography is the study of the shape and features of the surface of the Earth and other observable astronomical objects including planets, moons, and asteroids. Te topography of an area could refer to the surface shapes and features themselves, or a description (especially their depiction in maps).

Tis feld of geoscience and planetary science is concerned with local detail in general, including not only relief but also natural and artifcial features, and even local history and culture. Tis meaning is less common in the United States, where

442 topographic maps with elevation contours have made "topography" synonymous with relief. Te older sense of topography as the study of place still has currency in Europe.

Topography in a narrow sense involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identifcation of specifc landforms. Tis is also known as geomorphometry. In modern usage, this involves generation of elevation data in digital form (DEM). It is often considered to include the graphic representation of the landform on a map by a variety of techniques, including contour lines, hypsometric tints, and relief shading.

Bathymetry is the study of underwater depth of lake or ocean foors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. Te name comes from Greek βαθύς (bathus), "deep",[1] and μέτρον (metron), "measure".[2] Bathymetric (or hydrographic) charts are typically produced to support safety of surface or sub-surface navigation, and usually show seafoor relief or terrain as contour lines (called depth contours or isobaths) and selected depths (soundings), and typically also provide surface navigational information. Bathymetric maps (a more general term where navigational safety is not a concern) may also use a Digital Terrain Model and artifcial illumination techniques to illustrate the depths being portrayed.

Processes

Gorge cut by the Indus river into bedrock, Nanga Parbat region, Pakistan. Tis is the deepest river canyon in the world. Nanga Parbat itself, the world's 9th highest mountain, is seen in the background.

Geomorphically relevant processes generally fall into (1) the production of regolith by weathering and erosion, (2) the transport of that material, and (3) its eventual deposition. Primary surface processes responsible for most topographic features include wind, waves, chemical dissolution, mass wasting, groundwater movement, surface water fow, glacial action, tectonism, and volcanism. Other more exotic geomorphic processes might include periglacial (freeze-thaw) processes, salt- mediated action, marine currents activity, seepage of fuids through the seafoor or extraterrestrial impact.

Aeolian processes

Aeolian processes pertain to the activity of the winds and more specifcally, to the winds' ability to shape the surface of the Earth. Winds may erode, transport, and deposit materials, and are eﬀective agents in regions with sparse vegetation and a large supply of fne, unconsolidated sediments. Although water and mass fow tend to mobilize more material than wind in most environments, aeolian processes are important in arid environments such as deserts.[39]

Biological processes

Beaver dams, as this one in Tierra del Fuego, constitute a specifc form of zoogeomorphology, a type of biogeomorphology, Te interaction of living organisms with landforms, or biogeomorphologic processes, can be of many diﬀerent forms, and is probably of profound importance for the terrestrial geomorphic system as a whole. Biology can infuence very many geomorphic processes, ranging from biogeochemical processes controlling chemical weathering, to the infuence of mechanical processes like burrowing and tree throw on soil development, to even controlling global erosion rates through modulation of climate through carbon dioxide balance. Terrestrial landscapes in which the role of biology in mediating surface processes can be defnitively excluded are extremely rare, but may hold important information for understanding the geomorphology of other planets, such as Mars.

Fluvial processes

Seif and barchan dunes in the Hellespontus region on the surface of Mars. Dunes are mobile landforms created by the transport of large volumes of sand by wind. Rivers and streams are not only conduits of water, but also of sediment. Te water, as it fows over the channel bed, is able to mobilize sediment and transport it downstream, either as bed load, suspended load or dissolved load. Te rate of sediment transport depends on the availability of sediment itself and on the river's discharge. Rivers are also capable of eroding into rock and creating new sediment, both from their own beds and also by coupling to the surrounding hillslopes. In this way, rivers are thought of as setting the base level for large-scale landscape evolution in nonglacial environments. Rivers are key links in the connectivity of diﬀerent landscape elements.

As rivers fow across the landscape, they generally increase in size, merging with other rivers. Te network of rivers thus formed is a drainage system. Tese systems take on four general patterns: dendritic, radial, rectangular, and trellis. Dendritic happens to be the most common, occurring when the underlying stratum is stable (without faulting). Drainage systems have

443 four primary components: drainage basin, alluvial valley, delta plain, and receiving basin. Some geomorphic examples of fuvial landforms are alluvial fans, oxbow lakes, and fuvial terraces.

Glacial processes

Features of a glacial landscape. Glaciers, while geographically restricted, are eﬀective agents of landscape change. Te gradual movement of ice down a valley causes abrasion and plucking of the underlying rock. Abrasion produces fne sediment, termed glacial four. Te debris transported by the glacier, when the glacier recedes, is termed a moraine. Glacial erosion is responsible for U-shaped valleys, as opposed to the V-shaped valleys of fuvial origin.

Te way glacial processes interact with other landscape elements, particularly hillslope and fuvial processes, is an important aspect of Plio-Pleistocene landscape evolution and its sedimentary record in many high mountain environments. Environments that have been relatively recently glaciated but are no longer may still show elevated landscape change rates compared to those that have never been glaciated. Nonglacial geomorphic processes which nevertheless have been conditioned by past glaciation are termed paraglacial processes. Tis concept contrasts with periglacial processes, which are directly driven by formation or melting of ice or frost.

Hillslope processes

Talus cones on the north shore of Isforden, Svalbard, Norway. Talus cones are accumulations of coarse hillslope debris at the foot of the slopes producing the material. Te Ferguson Slide is an active landslide in the Merced River canyon on California State Highway 140, a primary access road to Yosemite National Park. Soil, regolith, and rock move downslope under the force of gravity via creep, slides, fows, topples, and falls. Such mass wasting occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus, Titan and Iapetus.

Ongoing hillslope processes can change the topology of the hillslope surface, which in turn can change the rates of those processes. Hillslopes that steepen up to certain critical thresholds are capable of shedding extremely large volumes of material very quickly, making hillslope processes an extremely important element of landscapes in tectonically active areas.

On the Earth, biological processes such as burrowing or tree throw may play important roles in setting the rates of some hillslope processes.

Both volcanic (eruptive) and plutonic (intrusive) igneous processes can have important impacts on geomorphology. Te action of volcanoes tends to rejuvenize landscapes, covering the old land surface with lava and tephra, releasing pyroclastic material and forcing rivers through new paths. Te cones built by eruptions also build substantial new topography, which can be acted upon by other surface processes. Plutonic rocks intruding then solidifying at depth can cause both uplift or subsidence of the surface, depending on whether the new material is denser or less dense than the rock it displaces.

Tectonic eﬀects on geomorphology can range from scales of millions of years to minutes or less. Te eﬀects of tectonics on landscape are heavily dependent on the nature of the underlying bedrock fabric that more or less controls what kind of local morphology tectonics can shape. Earthquakes can, in terms of minutes, submerge large areas of land creating new wetlands. Isostatic rebound can account for signifcant changes over hundreds to thousands of years, and allows erosion of a mountain belt to promote further erosion as mass is removed from the chain and the belt uplifts. Long-term plate tectonic dynamics give rise to orogenic belts, large mountain chains with typical lifetimes of many tens of millions of years, which form focal points for high rates of fuvial and hillslope processes and thus long-term sediment production.

Features of deeper mantle dynamics such as plumes and delamination of the lower lithosphere have also been hypothesised to play important roles in the long term (> million year), large scale (thousands of km) evolution of the Earth's topography (see dynamic topography). Both can promote surface uplift through isostasy as hotter, less dense, mantle rocks displace cooler, denser, mantle rocks at depth in the Earth.

Marine processes are those associated with the action of waves, marine currents and seepage of fuids through the seafoor. Mass wasting and submarine landsliding are also important processes for some aspects of marine geomorphology. Because ocean basins are the ultimate sinks for a large fraction of terrestrial sediments, depositional processes and their related forms (e.g., sediment fans, deltas) are particularly important as elements of marine geomorphology.

Ecology (from Greek: οἶκος, "house", or "environment"; -λογία, "study of")[A] is the scientifc study of interactions among organisms and their environment. It is an interdisciplinary feld that straddles biology, geography, and Earth science. Objects of study include interactions of organisms with each other and with abiotic components of their environment. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and 444 competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and niche construction, regulate the fux of energy and matter through an environment. Tese processes are sustained by organisms with specifc life history traits. Biodiversity means the varieties of species, genes, and ecosystems, enhances certain ecosystem services.

Ecology is not synonymous with environmentalism, natural history, or environmental science. It overlaps with the closely related sciences of evolutionary biology, genetics, and ethology. An important focus for ecologists is to improve the understanding of how biodiversity aﬀects ecological function. Ecologists seek to explain:

Te abundance and distribution of organisms and biodiversity in the context of the environment. Ecology has practical applications in conservation biology, wetland management, natural resource management (agroecology, agriculture, forestry, agroforestry, fsheries), city planning (urban ecology), community health, economics, basic and applied science, and human social interaction (human ecology). For example, the Circles of Sustainability approach treats ecology as more than the environment 'out there'. It is not treated as separate from humans. Organisms (including humans) and resources compose ecosystems which, in turn, maintain biophysical feedback mechanisms that moderate processes acting on living (biotic) and non-living (abiotic) components of the planet. Ecosystems sustain life-supporting functions and produce natural capital like biomass production (food, fuel, fber, and medicine), the regulation of climate, global biogeochemical cycles, water fltration, soil formation, erosion control, food protection, and many other natural features of scientifc, historical, economic, or intrinsic value.

Te word "ecology" ("Ökologie") was coined in 1866 by the German scientist Ernst Haeckel. Ecological thought is derivative of established currents in philosophy, particularly from ethics and politics. Ancient Greek philosophers such as Hippocrates and Aristotle laid the foundations of ecology in their studies on natural history. Modern ecology became a much more rigorous science in the late 19th century. Evolutionary concepts relating to adaptation and natural selection became the cornerstones of modern ecological theory.

An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. Tese biotic and abiotic components are regarded as linked together through nutrient cycles and energy fows. As ecosystems are defned by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specifc, limited spaces (although some scientists say that the entire planet is an ecosystem). Energy, water, nitrogen and soil minerals are other essential abiotic components of an ecosystem. Te energy that fows through ecosystems is obtained primarily from the sun. It generally enters the system through photosynthesis, a process that also captures carbon dioxide from the atmosphere. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. Tey also infuence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and other microbes.

Ecosystems are controlled both by external and internal factors. External factors such as climate, the parent material that forms the soil, and topography control the overall structure of an ecosystem and the way things work within it, but are not themselves infuenced by the ecosystem. Other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to periodic disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can have very different characteristics simply because they contain different species. Te introduction of non-native species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are also controlled by them and are often subject to feedback loops. While the resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other internal factors include disturbance, succession and the types of species present. Although humans exist and operate within ecosystems, their cumulative effects are large enough to infuence external factors like climate.

Biodiversity aﬀects ecosystem function, as do the processes of disturbance and succession. Ecosystems provide a variety of goods and services upon which people depend; the principles of ecosystem management suggest that rather than managing individual species, natural resources should be managed at the level of the ecosystem itself. Classifying ecosystems into ecologically homogeneous units is an important step towards eﬀective ecosystem management, but there is no single, agreed- upon way to do this.

Biodiversity (an abbreviation of "biological diversity") describes the diversity of life from genes to ecosystems and spans every level of biological organization. Te term has several interpretations, and there are many ways to index, measure, 445 characterize, and represent its complex organization. Biodiversity includes species diversity, ecosystem diversity, and genetic diversity and scientists are interested in the way that this diversity aﬀects the complex ecological processes operating at and among these respective levels. Biodiversity plays an important role in ecosystem services which by defnition maintain and improve human quality of life. Conservation priorities and management techniques require diﬀerent approaches and considerations to address the full ecological scope of biodiversity. Natural capital that supports populations is critical for maintaining ecosystem services and species migration (e.g., riverine fsh runs and avian insect control) has been implicated as one mechanism by which those service losses are experienced. An understanding of biodiversity has practical applications for species and ecosystem-level conservation planners as they make management recommendations to consulting frms, governments, and industry.

Te habitat of a species describes the environment over which a species is known to occur and the type of community that is formed as a result. More specifcally, "habitats can be defned as regions in environmental space that are composed of multiple dimensions, each representing a biotic or abiotic environmental variable; that is, any component or characteristic of the environment related directly (e.g. forage biomass and quality) or indirectly (e.g. elevation) to the use of a location by the animal."[23]:745 For example, a habitat might be an aquatic or terrestrial environment that can be further categorized as a montane or alpine ecosystem. Habitat shifts provide important evidence of competition in nature where one population changes relative to the habitats that most other individuals of the species occupy. For example, one population of a species of tropical lizards (Tropidurus hispidus) has a fattened body relative to the main populations that live in open savanna. Te population that lives in an isolated rock outcrop hides in crevasses where its fattened body oﬀers a selective advantage. Habitat shifts also occur in the developmental life history of amphibians, and in insects that transition from aquatic to terrestrial habitats. Biotope and habitat are sometimes used interchangeably, but the former applies to a community's environment, whereas the latter applies to a species' environment.

Additionally, some species are ecosystem engineers, altering the environment within a localized region. For instance, beavers manage water levels by building dams which improves their habitat in a landscape.

Te biophysical environment is the biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an infuence in their survival, development, and evolution. Te biophysical environment can vary in scale from microscopic to global in extent. It can also be subdivided according to its attributes. Examples include the marine environment, the atmospheric environment and the terrestrial environment.Te number of biophysical environments is countless, given that each living organism has its own environment.

Life is a characteristic that distinguishes physical entities that do have biological processes, such as signaling and self- sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classifed as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. Te criteria can at times be ambiguous and may or may not defne viruses, viroids, or potential artifcial life as "living". Biology is the primary science concerned with the study of life, although many other sciences are involved.

Te defnition of life is controversial. Te current defnition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce. However, many other biological defnitions have been proposed, and there are some borderline cases of life, such as viruses. Troughout history, there have been many attempts to defne what is meant by "life" and many theories on the properties and emergence of living things, such as materialism, the belief that everything is made out of matter and that life is merely a complex form of it; hylomorphism, the belief that all things are a combination of matter and form, and the form of a living thing is its soul; spontaneous generation, the belief that life repeatedly emerges from non- life; and vitalism, a now largely discredited hypothesis that living organisms possess a "life force" or "vital spark". Modern defnitions are more complex, with input from a diversity of scientifc disciplines. Biophysicists have proposed many defnitions based on chemical systems; there are also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of ecological systems, and yet another is elaborated in complex systems biology, a branch or subfeld of mathematical biology. Abiogenesis describes the natural process of life arising from non-living matter, such as simple organic compounds. Properties common to all organisms include the need for certain core chemical elements to sustain biochemical functions.

Life on Earth frst appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Earth's current life may have descended from an RNA world, although RNA-based life may not have been the frst. Te mechanism by which life began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment. Te earliest known life forms are microfossils of bacteria. 3.45 billion year old Australian rocks are reported to have contained microorganisms. In 2016,

446 scientists reported identifying a set of 355 genes thought to be present in the last universal common ancestor (LUCA) of all living organisms, already a complex organism and not the frst living thing.

Since its primordial beginnings, life on Earth has changed its environment on a geologic time scale. To survive in most ecosystems, life must often adapt to a wide range of conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth. Aristotle was the frst person to classify organisms. Later, Carl Linnaeus introduced his system of binomial nomenclature for the classifcation of species. Eventually new groups and categories of life were discovered, such as cells and microorganisms, forcing dramatic revisions of the structure of relationships between living organisms. Cells are sometimes considered the smallest units and "building blocks" of life. Tere are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many biomolecules such as proteins and nucleic acids. Cells reproduce through a process of cell division, in which the parent cell divides into two or more daughter cells.

Tough currently only known on Earth, life need not be restricted to it, and many scientists speculate in the existence of extraterrestrial life. Artifcial life is a computer simulation or man-made reconstruction of any aspect of life, which is often used to examine systems related to natural life. Death is the permanent termination of all biological functions which sustain an organism, and as such, is the end of its life. Extinction is the process by which an entire group or taxon, normally a species, dies out. Fossils are the preserved remains or traces of organisms.

Plants

Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. In one sense (circumscription), the term refers to green plants, which form an unranked clade Viridiplantae (Latin for "green plants"). Tis includes the fowering plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae, and excludes the red and brown algae. Historically, plants formed one of two kingdoms covering all living things that were not animals, and both algae and fungi were treated as plants; however all current defnitions of "plant" exclude the fungi and some algae, as well as the prokaryotes (the archaea and bacteria).

Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts, derived from endosymbiosis with cyanobacteria. Teir chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is also common.

Tere are about 300–315 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants (see the table below). Green plants provide a substantial proportion of the world's molecular oxygen and are the basis of most of Earth's ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankind's basic foodstuﬀs, and have been domesticated for millennia. Plants play many roles in culture. Tey are used as ornaments and, until recently and in great variety, they have served as the source of most medicines and drugs. Te scientifc study of plants is known as botany, a branch of biology.

A seed is an embryonic plant enclosed in a protective outer covering. Te formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants.

Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. Te embryo is developed from the zygote and the seed coat from the integuments of the ovule.

Seeds have been an important development in the reproduction and success of gymnosperm and angiosperm plants, relative to more primitive plants such as ferns, mosses and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates.

Te term "seed" also has a general meaning that antedates the above—anything that can be sown, e.g. "seed" potatoes, "seeds" of corn or sunfower "seeds". In the case of sunfower and corn "seeds", what is sown is the seed enclosed in a shell or husk, whereas the potato is a tuber.

447 have a hardened fruit layer (the endocarp) fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut.

In botany and dendrology, a rhizome (/ˈraɪzoʊm/, from Ancient Greek: rhízōma "mass of roots",[1] from rhizóō "cause to strike root") is a modifed subterranean stem of a plant that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks and rootstocks. Rhizomes develop from axillary buds and grow perpendicular to the force of gravity. Te rhizome also retains the ability to allow new shoots to grow upwards.

If a rhizome is separated each piece may be able to give rise to a new plant. Te plant uses the rhizome to store starches, proteins, and other nutrients. Tese nutrients become useful for the plant when new shoots must be formed or when the plant dies back for the winter. Tis is a process known as vegetative reproduction and is used by farmers and gardeners to propagate certain plants. Tis also allows for lateral spread of grasses like bamboo and bunch grasses. Examples of plants that are propagated this way include hops, asparagus, ginger, irises, Lily of the Valley, cannas, and sympodial orchids. Some rhizomes which are used directly in cooking include ginger, turmeric, galangal, fngerroot, and lotus.

Stored rhizomes are subject to bacterial and fungal infections, making them unsuitable for replanting and greatly diminishing stocks. However, rhizomes can also be produced artifcially from tissue cultures. Te ability to easily grow rhizomes from tissue cultures leads to better stocks for replanting and greater yields. Te plant hormones ethylene and jasmonic acid have been found to help induce and regulate the growth of rhizomes, specifcally in rhubarb. Ethylene that was applied externally was found to aﬀect internal ethylene levels, allowing for easy manipulations of ethylene concentrations. Knowledge of how to use these hormones to induce rhizome growth could help farmers and biologists producing plants grown from rhizomes more easily cultivate and grow better plants.

A stolon is similar to a rhizome, but, unlike a rhizome, which is the main stem of the plant, a stolon sprouts from an existing stem, has long internodes, and generates new shoots at the end, such as in the strawberry plant. In general, rhizomes have short internodes; they send out roots from the bottom of the nodes and new upward-growing shoots from the top of the nodes. A stem tuber is a thickened part of a rhizome or stolon that has been enlarged for use as a storage organ.[6] In general, a tuber is high in starch, for example, the common potato, which is a modifed stolon. Te term tuber is often used imprecisely, and is sometimes applied to plants with rhizomes.

Some plants have rhizomes that grow above ground or that lie at the soil surface, including some Iris species, and ferns, whose spreading stems are rhizomes. Plants with underground rhizomes include gingers, bamboo, the Venus Flytrap, Chinese lantern, Western poison-oak, hops, and Alstroemeria, and the weeds Johnson grass, bermuda grass, and purple nut sedge. Rhizomes generally form a single layer, but in Giant Horsetails, can be multi-tiered.

Many rhizomes have culinary value, and some, such as zhe'ergen, are commonly consumed raw.

In general use, herbs are plants with savory or aromatic properties that are used for favoring food, in medicine, or as fragrances. Culinary use typically distinguishes herbs from spices. Herbs refer to the leafy green or fowering parts of a plant (either fresh or dried), while spices are usually dried and produced from other parts of the plant, including seeds, berries, bark, roots and fruits.

Herbs have a variety of uses including culinary, medicinal, and, in some cases, spiritual. General usage of the term "herb" diﬀers between culinary herbs and medicinal herbs; in medicinal or spiritual use, any parts of the plant might be considered as "herbs", including leaves, roots, fowers, seeds, root bark, inner bark (and cambium), resin and pericarp.

Te word "herb" is pronounced /hɜːrb/ in the Commonwealth, but /ɜːrb/ is common among North American speakers and those from other regions where h- dropping occurs. In botany, the word "herb" is also used as a synonym for "herbaceous plant”.

Culinary herbs are distinguished from vegetables in that, like spices, they are used in small amounts and provide favor rather than substance to food.

Herbs can be perennials such as thyme or lavender, biennials such as parsley, or annuals like basil. Perennial herbs can be shrubs such as rosemary, Rosmarinus oﬃcinalis, or trees such as bay laurel, Laurus nobilis – this contrasts with botanical herbs, which by defnition cannot be woody plants. Some plants are used as both herbs and spices, such as dill weed and dill seed or coriander leaves and seeds. Also, there are some herbs such as those in the mint family that are used for both culinary and medicinal purposes.

448 Some plants contain phytochemicals that have eﬀects on the body. Tere may be some eﬀects when consumed in the small levels that typify culinary "spicing", and some herbs are toxic in larger quantities. For instance, some types of herbal extract, such as the extract of St. John's-wort (Hypericum perforatum) or of kava (Piper methysticum) can be used for medical purposes to relieve depression and stress.[medical citation needed] However, large amounts of these herbs may lead to toxic overload that may involve complications, some of a serious nature, and should be used with caution. Complications can also arise when being taken with some prescription medicines.

Herbs have long been used as the basis of traditional Chinese herbal medicine, with usage dating as far back as the frst century CE and far before. In India, the Ayurveda medicinal system is based on herbs. Medicinal use of herbs in Western cultures has its roots in the Hippocratic (Greek) elemental healing system, based on a quaternary elemental healing metaphor. Famous herbalist of the Western tradition include Avicenna (Persian), Galen (Roman), Paracelsus (German Swiss), Culpepper (English) and the botanically inclined Eclectic physicians of 19th century/ early 20th century America (John Milton Scudder, Harvey Wickes Felter, John Uri Lloyd). Modern pharmaceuticals had their origins in crude herbal medicines, and to this day, some drugs are still extracted as fractionate/isolate compounds from raw herbs and then purifed to meet pharmaceutical standards.

Certain herbs contain psychoactive properties that have been used for both religious and recreational purposes by humans since the early Holocene era, notably the leaves and extracts of the cannabis and coca plants. Te leaves of the coca plant have been chewed by people in northern Peruvian societies for over 8,000 years, while the use of cannabis as a psychoactive substance dates back to the frst century CE in China and northern Africa.

Te indigenous peoples of Australia developed herbal medicine based on plants that were readily available to them. Te isolation of the indigenous people meant the remedies developed were for far less serious diseases, this was from not contracting western illnesses. Herbs such as river mint, wattle and eucalyptus were used for coughs, diarrhea, fever and headaches.

Herbs are used in many religions. For example, myrrh (Commiphora myrrha) and frankincense (Boswellia species) in Hellenistic religion, the nine herbs charm in Anglo-Saxon paganism, neem (Azadirachta indica) leaves, bael (Aegele marmelos) leaves, holy basil or tulsi (Ocimum tenuiforum), turmeric or "haldi" (Curcuma longa), cannabis in Hinduism, and white sage in Wicca. Rastafari also consider cannabis to be a holy plant.

Siberian shamans also used herbs for spiritual purposes. Plants may be used to induce spiritual experiences for rites of passage, such as vision quests in some Native American cultures. Te Cherokee Native Americans use both white sage and cedar for spiritual cleansing and smudging.

Te use of herbal cosmetics dates back to around six centuries ago in the European and Western countries. Mixtures and pastes were often concocted to whiten the face. During the 1940s, herbal cosmetics took a turn with the emerging red lipstick color, with every year gaining a more intense red. Herbal cosmetics come in many forms, such as face creams, scrubs, lipstick, natural fragrances, and body oils.

Mycelium is the vegetative part of a fungus or fungus-like bacterial colony, consisting of a mass of branching, thread-like hyphae. Te mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates into a homokaryotic mycelium, which cannot reproduce sexually; when two compatible homokaryotic mycelia join and form a dikaryotic mycelium, that mycelium may form fruiting bodies such as mushrooms. A mycelium may be minute, forming a colony that is too small to see, or it may be extensive:

Is this the largest organism in the world? Tis 2,400-acre [970-hectare] site in eastern Oregon had a contiguous growth of mycelium before logging roads cut through it. Estimated at 1,665 football felds in size and 2,200 years old, this one fungus has killed the forest above it several times over, and in so doing has built deeper soil layers that allow the growth of ever- larger stands of trees. Mushroom-forming forest fungi are unique in that their mycelial mats can achieve such massive proportions.

— Paul Stamets, Mycelium Running Trough the mycelium, a fungus absorbs nutrients from its environment. It does this in a two-stage process. First, the hyphae secrete enzymes onto or into the food source, which break down biological polymers into smaller units such as monomers. Tese monomers are then absorbed into the mycelium by facilitated diﬀusion and active transport.

449 Mycelium is vital in terrestrial and aquatic ecosystems for their role in the decomposition of plant material. Tey contribute to the organic fraction of soil, and their growth releases carbon dioxide back into the atmosphere (see carbon cycle). Ectomycorrhizal extramatrical mycelium, as well as the mycelium of Arbuscular mycorrhizal fungi increase the eﬃciency of water and nutrient absorption of most plants and confers resistance to some plant pathogens. Mycelium is an important food source for many soil invertebrates.

"Mycelium", like "fungus", can be considered a mass noun, a word that can be either singular or plural. Te term "mycelia", though, like "fungi", is often used as the preferred plural form. Mycelium forms to be like the lungs of the earth.

Sclerotia are compact or hard masses of mycelium.

One of the primary roles of fungi in an ecosystem is to decompose organic compounds. Petroleum products and some pesticides (typical soil contaminants) are organic molecules (i.e., they are built on a carbon structure), and thereby present a potential carbon source for fungi. Hence, fungi have the potential to eradicate such pollutants from their environment unless the chemicals prove toxic to the fungus. Tis biological degradation is a process known as bioremediation.

Mycelial mats have been suggested (see Paul Stamets) as having potential as biological flters, removing chemicals and microorganisms from soil and water. Te use of fungal mycelium to accomplish this has been termed mycofltration.

Knowledge of the relationship between mycorrhizal fungi and plants suggests new ways to improve crop yields. When spread on logging roads, mycelium can act as a binder, holding new soil in place and preventing washouts until woody plants can be established.

Since 2007, a company called Ecovative Design has been developing alternatives to polystyrene and plastic packaging by growing mycelium in agricultural waste. Te two ingredients are mixed together and placed into a mold for 3–5 days to grow into a durable material. Depending on the strain of mycelium used, they make many diﬀerent varieties of the material including water absorbent, fame retardant, and dielectric.

Fungi are essential for converting biomass into compost, as they decompose feedstock components such as lignin, which many other composting microorganisms cannot. Turning a backyard compost pile will commonly expose visible networks of mycelia that have formed on the decaying organic material within. Compost is an essential soil amendment and fertilizer for organic farming and gardening. Composting can divert a substantial fraction of municipal solid waste from landflls.

A fungus (plural: fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. Tese organisms are classifed as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants and animals.

A characteristic that places fungi in a diﬀerent kingdom from plants, bacteria, and some protists is chitin in their cell walls. Similar to animals, fungi are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesise. Growth is their means of mobility, except for spores (a few of which are fagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. Tese and other diﬀerences place fungi in a single group of related organisms, named the Eumycota (true fungi or Eumycetes), which share a common ancestor (form a monophyletic group), an interpretation that is also strongly supported by molecular phylogenetics. Tis fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). Te discipline of biology devoted to the study of fungi is known as mycology (from the Greek μύκης mykes, mushroom). In the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants.

Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites. Tey may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. Tey have long been used as a direct source of human food, in the form of mushrooms and truﬄes; as a leavening agent for bread; and in the fermentation of various food products, such as wine, beer, and soy sauce. Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals including humans. Te fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become signifcant pathogens of humans and other animals. 450 Losses of crops due to fungal diseases (e.g., rice blast disease) or food spoilage can have a large impact on human food supplies and local economies.

Te fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. However, little is known of the true biodiversity of Kingdom Fungi, which has been estimated at 2.2 million to 3.8 million species, of which only 120,000 have been described. 8000 of them are detrimental to plants and 300 can be pathogenic to humans. Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus, Christian Hendrik Persoon, and Elias Magnus Fries, fungi have been classifed according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the last decade have helped reshape the classifcation within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla.

Animals

Animals are eukaryotic, multicellular organisms that form the biological kingdom Animalia. With few exceptions, animals are motile (able to move), heterotrophic (consume organic material), reproduce sexually, and their embryonic development includes a blastula stage. Te body plan of the animal derives from this blastula, diﬀerentiating specialized tissues and organs as it develops; this plan eventually becomes fxed, although some undergo metamorphosis at some stage in their lives.

Vertebrates /ˈvɜːrtɪbrɪts/ comprise all species of animals within the subphylum Vertebrata /-eɪ/ (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 66,000 species described. Vertebrates include the jawless fsh and the jawed vertebrates, which include the cartilaginous fsh (sharks, rays, and ratfsh) and the bony fsh.

A bony fsh clade known as the lobe-fnned fshes is included with tetrapods, which are further divided into amphibians, reptiles, mammals, and birds. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm (0.30 in), to the blue whale, at up to 33 m (108 ft). Vertebrates make up less than fve percent of all described animal species; the rest are invertebrates, which lack vertebral columns.

Te vertebrates traditionally include the hagfsh, which do not have proper vertebrae due to their loss in evolution,[5] though their closest living relatives, the lampreys, do.[6] Hagfsh do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as "Craniata" when discussing morphology.

Molecular analysis since 1992 has suggested that hagfsh are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a sister group of vertebrates in the common taxon of craniata.

Wildlife traditionally refers to undomesticated animal species, but has come to include all plants, fungi, and other organisms that grow or live wild in an area without being introduced by humans.

Wildlife can be found in all ecosystems. Deserts, forests, rain forests, plains, grasslands and other areas including the most developed urban areas, all have distinct forms of wildlife. While the term in popular culture usually refers to animals that are untouched by human factors, most scientists agree that much wildlife is aﬀected by human activities.

Humans have historically tended to separate civilization from wildlife in a number of ways including the legal, social, and moral sense. Some animals, however, have adapted to suburban environments. Tis includes such animals as domesticated cats, dogs, mice, and gerbils. Some religions declare certain animals to be sacred, and in modern times concern for the natural environment has provoked activists to protest against the exploitation of wildlife for human beneft or entertainment.

Te global wildlife population has decreased by 52 percent between 1970 and 2014, according to a report by the World Wildlife Fund.

Zoology is the study of animals. Currently there are over 66 thousand (less than 5% of all animals) vertebrate species, and over 1.3 million (over 95% of all animals) invertebrate species in existence. Classifcation of animals into groups (taxonomy) is accomplished using either the hierarchical Linnaean system; or cladistics, which displays diagrams (phylogenetic trees) called cladograms to show relationships based on the evolutionary principle of the most recent common ancestor. Some recent classifcations based on modern cladistics have explicitly abandoned the term "kingdom", noting that the traditional kingdoms are not monophyletic, i.e., do not consist of all the descendants of a common ancestor. 451 Animals are divided by body plan into vertebrates and invertebrates. Vertebrates—fshes, amphibians, reptiles, birds, and mammals—have a vertebral column (spine); invertebrates do not. All vertebrates and most invertebrates are bilaterally symmetrical (Bilateria). Invertebrates include arthropods, molluscs, roundworms, ringed worms, fatworms, and other phyla in Ecdysozoa and Spiralia. Echinoderm larvae are initially bilaterally symmetrical, but later as adults develop radial symmetry; Cnidarians are radially symmetrical; ctenophores are biradially symmetrical; and sponges have no symmetry.

Animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals emerged as a clade within Apoikozoa as the sister group to the choanofagellates.

First, we don't even know how many types of animals there are in the world, let alone how many individual animals there are. Scientists have recently estimated that there are approximately 8.7 million species on Earth. Tey believe that 1-2 million of those species are animals.

Primatology is the scientifc study of primates. It is a diverse discipline at the boundary between mammalogy and anthropology, and researchers can be found in academic departments of anatomy, anthropology, biology, medicine, psychology, veterinary sciences and zoology, as well as in animal sanctuaries, biomedical research facilities, museums and zoos. Primatologists study both living and extinct primates in their natural habitats and in laboratories by conducting feld studies and experiments in order to understand aspects of their evolution and behaviour.

Ethology is the scientifc and objective study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism is a term that also describes the scientifc and objective study of animal behaviour, usually referring to measured responses to stimuli or trained behavioural responses in a laboratory context, without a particular emphasis on evolutionary adaptivity. Many naturalists have studied aspects of animal behaviour throughout history. Ethology has its scientifc roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. Te modern discipline of ethology is generally considered to have begun during the 1930s with the work of Dutch biologist Nikolaas Tinbergen and by Austrian biologists Konrad Lorenz and Karl von Frisch, joint awardees of the 1973 Nobel Prize in Physiology or Medicine. Ethology is a combination of laboratory and feld science, with a strong relation to some other disciplines such as neuroanatomy, ecology, and evolutionary biology. Ethologists are typically interested in a behavioural process rather than in a particular animal group, and often study one type of behaviour, such as aggression, in a number of unrelated animals.

Ethology is a rapidly growing feld. Since the dawn of the 21st century, many aspects of animal communication, emotions, culture, learning and sexuality that the scientifc community long thought it understood have been re-examined, and new conclusions reached. New felds, such as neuroethology, have developed.

Understanding ethology or animal behaviour can be important in animal training. Considering the natural behaviours of diﬀerent species or breeds enables the trainer to select the individuals best suited to perform the required task. It also enables the trainer to encourage the performance of naturally occurring behaviours and also the discontinuance of undesirable behaviours.

Climate is the statistics of weather over long periods of time. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate diﬀers from weather, in that weather only describes the short- term conditions of these variables in a given region. A region's climate is generated by the climate system, which has fve components: atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere.

Te climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water bodies and their currents. Climates can be classifed according to the average and the typical ranges of different variables, most commonly temperature and precipitation. Te most commonly used classifcation scheme was the Köppen climate classifcation. Te Tornthwaite system, in use since 1948, incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it. Te Bergeron and Spatial Synoptic Classifcation systems focus on the origin of air masses that defne the climate of a region.

Paleoclimatology is the study of ancient climates. Since direct observations of climate are not available before the 19th century, paleoclimates are inferred from proxy variables that include non-biotic evidence such as sediments found in lake beds and ice cores, and biotic evidence such as tree rings and coral. Climate models are mathematical models of past, present and future climates. Climate change may occur over long and short timescales from a variety of factors; recent warming is discussed in global warming. Global warming results in redistributions. For example, "a 3°C change in mean annual temperature corresponds to a shift in isotherms of approximately 300–400 km in latitude (in the temperate zone) or 500 m 452 in elevation. Terefore, species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones".

Te atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity. Te atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse eﬀect), and reducing temperature extremes between day and night (the diurnal temperature variation).

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air content and atmospheric pressure vary at diﬀerent layers, and air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in Earth's troposphere and in artifcial atmospheres.

Te atmosphere has a mass of about 5.15×1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. Te atmosphere becomes thinner and thinner with increasing altitude, with no defnite boundary between the atmosphere and outer space. Te Kármán line, at 100 km (62 mi), or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric eﬀects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition.

Te study of Earth's atmosphere and its processes is called atmospheric science (aerology). Early pioneers in the feld include Léon Teisserenc de Bout and Richard Assmann.

Te hydrosphere (from Greek ὕδωρ hydōr, "water" and σφαῖρα sphaira, "sphere") is the combined mass of water found on, under, and above the surface of a planet, minor planet or natural satellite.

It has been estimated that there are 1386 million cubic kilometers of water on Earth. Tis includes water in liquid and frozen forms in groundwater, oceans, lakes and streams. Saltwater accounts for 97.5% of this amount. Fresh water accounts for only 2.5%. Of this fresh water, 68.9% is in the form of ice and permanent snow cover in the Arctic, the Antarctic, and mountain glaciers. 30.8% is in the form of fresh groundwater. Only 0.3% of the fresh water on Earth is in easily accessible lakes, reservoirs and river systems.[3] Te total mass of the Earth's hydrosphere is about 1.4 × 1018 tonnes, which is about 0.023% of Earth's total mass. About 20 × 1012 tonnes of this is in Earth's atmosphere (for practical purposes, 1 cubic meter of water weighs one tonne). Approximately 75% of Earth's surface, an area of some 361 million square kilometers (139.5 million square miles), is covered by ocean. Te average salinity of Earth's oceans is about 35 grams of salt per kilogram of sea water (3.5%).

Te cryosphere (from the Greek κρύος kryos, "cold", "frost" or "ice" and σφαῖρα sphaira, "globe, ball"[1]) is those portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost). Tus, there is a wide overlap with the hydrosphere. Te cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its infuence on surface energy and moisture fuxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation. Trough these feedback processes, the cryosphere plays a signifcant role in the global climate and in climate model response to global changes. Te term deglaciation describes the retreat of cryospheric features. Cryology is the study of cryospheres.

A lithosphere (Ancient Greek: λίθος [lithos] for "rocky", and σφαίρα [sphaira] for "sphere") is the rigid, outermost shell of a terrestrial-type planet or natural satellite that is defned by its rigid mechanical properties. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. Te outermost shell of a rocky planet, the crust, is defned on the basis of its chemistry and mineralogy.

Te biosphere (from Greek βίος bíos "life" and σφαῖρα sphaira "sphere") also known as the ecosphere (from Greek οἶκος oîkos "environment" and

σφαῖρα), is the worldwide sum of all ecosystems. It can also be termed as the zone of life on Earth, a closed system (apart from solar and cosmic radiation and heat from the interior of the Earth), and largely self-regulating. By the most general biophysiological defnition, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere. Te biosphere is postulated to have evolved, beginning with a process of biopoiesis (life created naturally from non-living matter, such as simple organic compounds) or biogenesis (life created from living matter), at least some 3.5 billion years ago.

453 In a general sense, biospheres are any closed, self-regulating systems containing ecosystems. Tis includes artifcial biospheres such as Biosphere 2 and BIOS-3, and potentially ones on other planets or moons.

Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. Te study of meteorology dates back millennia, though signifcant progress in meteorology did not occur until the 18th century. Te 19th century saw modest progress in the feld after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It wasn't until after the elucidation of the laws of physics and, more particularly, the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that signifcant breakthroughs in weather forecasting were achieved.

Meteorological phenomena are observable weather events that are explained by the science of meteorology. Meteorological phenomena are described and quantifed by the variables of Earth's atmosphere: temperature, air pressure, water vapour, mass fow, and the variations and interactions of those variables, and how they change over time. Diﬀerent spatial scales are used to describe and predict weather on local, regional, and global levels.

Meteorology, climatology, atmospheric physics, and atmospheric chemistry are sub-disciplines of the atmospheric sciences. Meteorology and hydrology compose the interdisciplinary feld of hydrometeorology. Te interactions between Earth's atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse felds such as the military, energy production, transport, agriculture, and construction.

Te word "meteorology" is from Greek μετέωρος metéōros "lofty; high (in the sky)" (from μετα- meta- "above" and ἀείρω aeiro "I lift up") and - λογία -logia "-(o)logy", i.e. "the study of things in the air”.

Tides are the rise and fall of sea levels caused by the combined eﬀects of the gravitational forces exerted by the Moon and the Sun and the rotation of Earth.

Te times and amplitude of tides at any given locale are infuenced by the alignment of the Sun and Moon, by the pattern of tides in the deep ocean, by the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see Timing). Some shorelines experience a semi-diurnal tide—two nearly equal high and low tides each day. Other locations experience a diurnal tide—only one high and low tide each day. A "mixed tide"—two uneven tides a day, or one high and one low—is also possible.

Tides vary on timescales ranging from hours to years due to a number of factors. To make accurate records, tide gauges at fxed stations measure water level over time. Gauges ignore variations caused by waves with periods shorter than minutes. Tese data are compared to the reference (or datum) level usually called mean sea level.

While tides are usually the largest source of short-term sea-level fuctuations, sea levels are also subject to forces such as wind and barometric pressure changes, resulting in storm surges, especially in shallow seas and near coasts.

Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational feld that varies in time and space is present. For example, the solid part of the Earth is aﬀected by tides, though this is not as easily seen as the water tidal movements.

Mean sea level (MSL) (often shortened to sea level) is an average level of the surface of one or more of Earth's oceans from which heights such as elevations may be measured. MSL is a type of vertical datum – a standardised geodetic reference point – that is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft fight levels. A common and relatively straightforward mean sea-level standard is the midpoint between a mean low and mean high tide at a particular location.

Sea levels can be aﬀected by many factors and are known to have varied greatly over geological time scales. Te careful measurement of variations in MSL can oﬀer insights into ongoing climate change, and sea level rise has been widely quoted as evidence of ongoing global warming.

Te term above sea level generally refers to above mean sea level (AMSL).

Te water cycle, also known as the hydrological cycle or the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth. Te mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable 454 depending on a wide range of climatic variables. Te water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infltration, surface runoﬀ, and subsurface fow. In doing so, the water goes through diﬀerent forms: liquid, solid (ice) and vapor.

Te water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. Tese heat exchanges infuence climate.

Te evaporative phase of the cycle purifes water which then replenishes the land with freshwater. Te fow of liquid water and ice transports minerals across the globe. It is also involved in reshaping the geological features of the Earth, through processes including erosion and sedimentation. Te water cycle is also essential for the maintenance of most life and ecosystems on the planet.

Evaporation is a type of vaporization, that occurs on the surface of a liquid as it changes into the gaseous phase. Te surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other based on how they collide. When a molecule near the surface absorbs enough energy to overcome the vapor pressure, it will "escape" and enter the surrounding air as a gas. When evaporation occurs, the energy removed from the vaporized liquid, will reduce the temperature of the liquid resulting in evaporative cooling.

On average, only a fraction of the molecules in a liquid have enough heat energy to escape from the liquid. Te evaporation will continue until an equilibrium is reached when the evaporation of the liquid is the equal to its condensation. In an enclosed environment, the a liquid will evaporate until the surrounding air is saturated.

Condensation is the change of the physical state of matter from gas phase into liquid phase, and is the reverse of vapourisation. Te word most often refers to the water cycle. It can also be defned as the change in the state of water vapour to liquid water when in contact with a liquid or solid surface or cloud condensation nuclei within the atmosphere. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition (or desublimation, see Sublimation (phase transition).

In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. Te main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates". Tus, fog and mist are not precipitation but suspensions, because the water vapor does not condense suﬃciently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called "showers."

Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain. Tis process is typically active when freezing rain occurs. A stationary front is often present near the area of freezing rain and serves as the foci for forcing and rising air. Provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. Eventually, the cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects. Where relatively warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic fow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Tundersnow is possible within a cyclone's comma head and within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope fow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. Most precipitation occurs within the tropics and is caused by convection. Te movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.

Precipitation is a major component of the water cycle, and is responsible for depositing the fresh water on the planet. Approximately 505,000 cubic kilometres (121,000 cu mi) of water falls as precipitation each year; 398,000 cubic kilometres (95,000 cu mi) of it over the oceans and 107,000 cubic kilometres (26,000 cu mi) over land. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres (39 in), but over land it is only 715 millimetres (28.1 in). Climate classifcation systems such as the Köppen climate classifcation system use average annual rainfall to help diﬀerentiate between diﬀering climate regimes.

Precipitation may occur on other celestial bodies, e.g. when it gets cold, Mars has precipitation which most likely takes the form of frost, rather than rain or snow.

455 Infltration is the process by which water on the ground surface enters the soil. Infltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. Te rate decreases as the soil becomes saturated. If the precipitation rate exceeds the infltration rate, runoﬀ will usually occur unless there is some physical barrier. It is related to the saturated hydraulic conductivity of the near-surface soil. Te rate of infltration can be measured using an infltrometer.

Surface runoff (also known as overland fow) is the fow of water that occurs when excess stormwater, meltwater, or other sources fows over the Earth's surface. Tis might occur because soil is saturated to full capacity, because rain arrives more quickly than soil can absorb it, or because impervious areas (roofs and pavement) send their runoff to surrounding soil that cannot absorb all of it. Surface runoff is a major component of the water cycle. It is the primary agent in soil erosion by water.

Runoff that occurs on the ground surface before reaching a channel is also called a nonpoint source. If a nonpoint source contains man-made contaminants, or natural forms of pollution (such as rotting leaves) the runoff is called nonpoint source pollution. A land area which produces runoff that drains to a common point is called a drainage basin. When runoff fows along the ground, it can pick up soil contaminants including petroleum, pesticides, or fertilizers that become discharge or nonpoint source pollution.

In addition to causing water erosion and pollution, surface runoﬀ in urban areas is a primary cause of urban fooding which can result in property damage, damp and mold in basements, and street fooding.

Evaporation is an essential part of the water cycle. Te sun (solar energy) drives evaporation of water from oceans, lakes, moisture in the soil, and other sources of water. In hydrology, evaporation and transpiration (which involves evaporation within plant stomata) are collectively termed evapotranspiration. Evaporation of water occurs when the surface of the liquid is exposed, allowing molecules to escape and form water vapor; this vapor can then rise up and form clouds. With suﬃcient energy, the liquid will turn into vapor.

Climatology (from Greek κλίμα, klima, "place, zone"; and -λογία, -logia) or climate science is the scientifc study of climate, scientifcally defned as weather conditions averaged over a period of time.[1] Tis modern feld of study is regarded as a branch of the atmospheric sciences and a subfeld of physical geography, which is one of the Earth sciences. Climatology now includes aspects of oceanography and biogeochemistry. Basic knowledge of climate can be used within shorter term weather forecasting using analog techniques such as the El Niño–Southern Oscillation (ENSO), the Madden–Julian oscillation (MJO), the North Atlantic oscillation (NAO), the Northern Annular Mode (NAM) which is also known as the Arctic oscillation (AO), the Northern Pacifc (NP) Index, the Pacifc decadal oscillation (PDO), and the Interdecadal Pacifc Oscillation (IPO). Climate models are used for a variety of purposes from study of the dynamics of the weather and climate system to projections of future climate. Weather is known as the condition of the atmosphere over a period of time, while climate has to do with the atmospheric condition over an extended to indefnite period of time.

Atmospheric sciences is a term for the study of the |Earth's atmosphere]], its processes, the eﬀects other systems have on the atmosphere, and the eﬀects of the atmosphere on these other systems. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather forecasting. Climatology is the study of atmospheric changes (both long and short-term) that defne average climates and their change over time, due to both natural and anthropogenic climate variability. Aeronomy is the study of the upper layers of the atmosphere, where dissociation and ionization are important. Atmospheric science has been extended to the feld of planetary science and the study of the atmospheres of the planets of the solar system.

Experimental instruments used in atmospheric sciences include satellites, rocketsondes, radiosondes, weather balloons, and lasers.

Te term aerology (from Greek ἀήρ, aēr, "air"; and -λογία, -logia) is sometimes used as an alternative term for the study of Earth's atmosphere. Early pioneers in the feld include Léon Teisserenc de Bort and Richard Assmann.

Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution. In 2015, pollution killed 9 million people in the world. he burning of coal and wood, and the presence of many horses in concentrated areas made the cities the primary sources of pollution. Te Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply. King Edward I of England banned the burning of sea- coal by proclamation in London in 1272, after its 456 smoke became a problem.[6][7] But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow.

It was the industrial revolution that gave birth to environmental pollution as we know it today. London also recorded one of the earlier extreme cases of water quality problems with the Great Stink on the Tames of 1858, which led to construction of the London sewerage system soon afterward. Pollution issues escalated as population growth far exceeded view ability of neighborhoods to handle their waste problem. Reformers began to demand sewer systems, and clean water.

In 1870, the sanitary conditions in Berlin were among the worst in Europe. August Bebel recalled conditions before a modern sewer system was built in the late 1870s:

"Waste-water from the houses collected in the gutters running alongside the curbs and emitted a truly fearsome smell. Tere were no public toilets in the streets or squares. Visitors, especially women, often became desperate when nature called. In the public buildings the sanitary facilities were unbelievably primitive....As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870.” Te primitive conditions were intolerable for a world national capital, and the Imperial German government brought in its scientists, engineers and urban planners to not only solve the defciencies but to forge Berlin as the world's model city. A British expert in 1906 concluded that Berlin represented "the most complete application of science, order and method of public life," adding "it is a marvel of civic administration, the most modern and most perfectly organized city that there is."

Te emergence of great factories and consumption of immense quantities of coal gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. Chicago and Cincinnati were the frst two American cities to enact laws ensuring cleaner air in 1881. Pollution became a major issue in the United States in the early twentieth century, as progressive reformers took issue with air pollution caused by coal burning, water pollution caused by bad sanitation, and street pollution caused by the 3 million horses who worked in American cities in 1900, generating large quantities of urine and manure. As historian Martin Melosi notes, Te generation that frst saw automobiles replacing the horses saw cars as "miracles of cleanliness.". By the 1940s, however, automobile- caused smog was a major issue in Los Angeles.

Other cities followed around the country until early in the 20th century, when the short lived Oﬃce of Air Pollution was created under the Department of the Interior. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as another public reminder. Air pollution would continue to be a problem in England, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952.

Awareness of atmospheric pollution spread widely after World War II, with fears triggered by reports of radioactive fallout from atomic warfare and testing. Ten a non-nuclear event, Te Great Smog of 1952 in London, killed at least 4000 people. Tis prompted some of the frst major modern environmental legislation, Te Clean Air Act of 1956.

Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water Act and the National Environmental Policy Act.

Te major forms of pollution are listed below along with the particular contaminant relevant to each of them:

Air pollution: the release of chemicals and particulates into the atmosphere. Common gaseous pollutants include carbon monoxide, sulfur dioxide, chlorofuorocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fne dust is characterized by their micrometre size PM10 to PM2.5.

Light pollution: includes light trespass, over-illumination and astronomical interference. Littering: the criminal throwing of inappropriate man-made objects, unremoved, onto public and private properties. Noise pollution: which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar. Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most signifcant soil contaminants are hydrocarbons, heavy metals, MTBE,[22] herbicides, pesticides and chlorinated hydrocarbons. Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment. (See alpha emitters and actinides in the environment.) Termal pollution, is a temperature change in natural water bodies caused by human infuence, such as use of water as coolant in a power plant. Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash, municipal solid waste or space debris.Water pollution, by the discharge of wastewater from commercial and industrial waste (intentionally or through spills) into surface waters; discharges of untreated domestic sewage, and chemical contaminants, such as chlorine, from treated sewage; release of waste and

457 contaminants into surface runoff fowing to surface waters (including urban runoff and agricultural runoff, which may contain chemical fertilizers and pesticides); waste disposal and leaching into groundwater; eutrophication and littering. Plastic pollution: involves the accumulation of plastic products in the environment that adversely affects wildlife, wildlife habitat, or humans.

Air pollution comes from both natural and human-made (anthropogenic) sources. However, globally human-made pollutants from combustion, construction, mining, agriculture and warfare are increasingly signifcant in the air pollution equation.

Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refneries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur.

Pollution has been found to be present widely in the environment. Tere are a number of eﬀects of this:

Biomagnifcation describes situations where toxins (such as heavy metals) may pass through trophic levels, becoming exponentially more concentrated in the process. Carbon dioxide emissions cause ocean acidifcation, the ongoing decrease in the pH of the Earth's oceans as CO2 becomes dissolved.

Te emission of greenhouse gases leads to global warming which aﬀects ecosystems in many ways. Invasive species can out compete native species and reduce biodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness. Nitrogen oxides are removed from the air by rain and fertilise land which can change the species composition of ecosystems.

Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis and leads to the production of tropospheric ozone which damages plants. Soil can become infertile and unsuitable for plants. Tis will aﬀect other organisms in the food web. Sulfur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of soil.

Global warming, also referred to as climate change, is the observed century-scale rise in the average temperature of the Earth's climate system and its related eﬀects. Multiple lines of scientifc evidence show that the climate system is warming. Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid-19th century, and in paleoclimate proxy records covering thousands of years.

Future climate change and associated impacts will differ from region to region. Anticipated effects include increasing global temperatures, rising sea levels, changing precipitation, and expansion of deserts in the subtropics. Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the continuing retreat of glaciers, permafrost and sea ice. Other likely changes include more frequent extreme weather events such as heat waves, droughts, heavy rainfall with foods and heavy snowfall; ocean acidifcation; and species extinctions due to shifting temperature regimes. Effects signifcant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels. Because the climate system has a large "inertia" and greenhouse gases will remain in the atmosphere for a long time, many of these effects will persist for not only decades or centuries, but for tens of thousands of years to come.

Possible societal responses to global warming include mitigation by emissions reduction, adaptation to its effects, building systems resilient to its effects, and possible future climate engineering. Most countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC),[20] whose ultimate objective is to prevent dangerous anthropogenic climate change. Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 °C (3.6 °F) compared to pre-industrial levels, with efforts made to limit warming to 1.5 °C (2.7 °F).

Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather within the context of longer-term average conditions. Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have been identifed as primary causes of ongoing climate change, often referred to as global warming.

Scientists actively work to understand past and future climate by using observations and theoretical models. A climate record —extending deep into the Earth's past—has been assembled, and continues to be built up, based on geological evidence from borehole temperature profles, cores removed from deep accumulations of ice, foral and faunal records, glacial and periglacial processes, stable-isotope and other analyses of sediment layers, and records of past sea levels. More recent data are

458 provided by the instrumental record. General circulation models, based on the physical sciences, are often used in theoretical approaches to match past climate data, make future projections, and link causes and eﬀects in climate change.

Te Gaia hypothesis (/ˈɡaɪ.ə/ GYE-ə, /ˈɡeɪ.ə/ GAY-ə), also known as the Gaia theory or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.

Te hypothesis was formulated by the chemist James Lovelock[1] and co-developed by the microbiologist Lynn Margulis in the 1970s. Lovelock named the idea after Gaia, the primordial goddess who personifed the Earth in Greek mythology. In 2006, the Geological Society of London awarded Lovelock the Wollaston Medal in part for his work on the Gaia hypothesis.

Te Gaia hypothesis was initially criticized for being teleological and against the principles of natural selection, but later refnements aligned the Gaia hypothesis with ideas from felds such as Earth system science, biogeochemistry and systems ecology. Lovelock also once described the "geophysiology" of the Earth. Even so, the Gaia hypothesis continues to attract criticism, and today some scientists consider it to be only weakly supported by, or at odds with, the available evidence.

Since life started on Earth, the energy provided by the Sun has increased by 25% to 30%; however, the surface temperature of the planet has remained within the levels of habitability, reaching quite regular low and high margins. Lovelock has also hypothesised that methanogens produced elevated levels of methane in the early atmosphere, giving a view similar to that found in petrochemical smog, similar in some respects to the atmosphere on Titan. Tis, he suggests tended to screen out ultraviolet until the formation of the ozone screen, maintaining a degree of homeostasis. However, the Snowball Earth research has suggested that "oxygen shocks" and reduced methane levels led, during the Huronian, Sturtian and Marinoan/ Varanger Ice Ages, to a world that very nearly became a solid "snowball". Tese epochs are evidence against the ability of the pre Phanerozoic biosphere to fully self-regulate.

Processing of the greenhouse gas CO2, explained below, plays a critical role in the maintenance of the Earth temperature within the limits of habitability.

Te CLAW hypothesis, inspired by the Gaia hypothesis, proposes a feedback loop that operates between ocean ecosystems and the Earth's climate. Te hypothesis specifcally proposes that particular phytoplankton that produce dimethyl sulfde are responsive to variations in climate forcing, and that these responses lead to a negative feedback loop that acts to stabilise the temperature of the Earth's atmosphere.

Currently the increase in human population and the environmental impact of their activities, such as the multiplication of greenhouse gases may cause negative feedbacks in the environment to become positive feedback. Lovelock has stated that this could bring an extremely accelerated global warming, but he has since stated the eﬀects will likely occur more slowly.

James Lovelock and Andrew Watson developed the mathematical model Daisyworld, in which temperature regulation arises from a simple ecosystem consisting of two species whose activity varies in response to the planet's environment. Te model demonstrates that benefcial feedback mechanisms can emerge in this "toy world" containing only self-interested organisms rather than through classic group selection mechanisms.

Daisyworld examines the energy budget of a planet populated by two diﬀerent types of plants, black daisies and white daisies. Te colour of the daisies infuences the albedo of the planet such that black daisies absorb light and warm the planet, while white daisies refect light and cool the planet. As the model runs the output of the "sun" increases, meaning that the surface temperature of an uninhabited "gray" planet will steadily rise. In contrast, on Daisyworld competition between the daisies (based on temperature-eﬀects on growth rates) leads to a shifting balance of daisy populations that tends to favour a planetary temperature close to the optimum for daisy growth.

It has been suggested that the results were predictable because Lovelock and Watson selected examples that produced the responses they desired.

Ocean salinity has been constant at about 3.5% for a very long time. Salinity stability in oceanic environments is important as most cells require a rather constant salinity and do not generally tolerate values above 5%. Te constant ocean salinity was a long-standing mystery, because no process counterbalancing the salt infux from rivers was known. Recently it was suggested[23] that salinity may also be strongly infuenced by seawater circulation through hot basaltic rocks, and emerging 459 as hot water vents on mid-ocean ridges. However, the composition of seawater is far from equilibrium, and it is diﬃcult to explain this fact without the infuence of organic processes. One suggested explanation lies in the formation of salt plains throughout Earth's history. It is hypothesized that these are created by bacterial colonies that fx ions and heavy metals during their life processes.

In the biogeochemical processes of the earth, sources and sinks are the movement of elements. Te composition of salt ions within our oceans and seas are: sodium (Na+), chlorine (Cl−), sulfate (SO42−), Magnesium (Mg2+), calcium (Ca2+) and potassium (K+). Te elements that comprise salinity do not readily change and are a conservative property of seawater.[22] Tere are many mechanisms that change salinity from a particulate form to a dissolved form and back. Te known sources of sodium i.e. salts is when weathering, erosion, and dissolution of rocks transport into rivers and deposit into the oceans.

Te Mediterranean Sea as being Gaia's kidney is found (here) by Kenneth J. Hsue a correspondence author in 2001. Te "desiccation" of the Mediterranean is the evidence of a functioning kidney. Earlier "kidney functions" were performed during the "deposition of the Cretaceous (South Atlantic), Jurassic (Gulf of Mexico), Permo-Triassic (Europe), Devonian (Canada), Cambrian/Precambrian (Gondwana) saline giants.”

Te Gaia hypothesis states that the Earth's atmospheric composition is kept at a dynamically steady state by the presence of life. Te atmospheric composition provides the conditions that contemporary life has adapted to. All the atmospheric gases other than noble gases present in the atmosphere are either made by organisms or processed by them.

Te stability of the atmosphere in Earth is not a consequence of chemical equilibrium. Oxygen is a reactive compound, and should eventually combine with gases and minerals of the Earth's atmosphere and crust. Oxygen only began to persist in the atmosphere in small quantities about 50 million years before the start of the Great Oxygenation Event. Since the start of the Cambrian period, atmospheric oxygen concentrations have fuctuated between 15% and 35% of atmospheric volume. Traces of methane (at an amount of 100,000 tonnes produced per year) should not exist, as methane is combustible in an oxygen atmosphere.

Dry air in the atmosphere of Earth contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases including methane. Lovelock originally speculated that concentrations of oxygen above about 25% would increase the frequency of wildfres and confagration of forests. Recent work on the fndings of fre-caused charcoal in Carboniferous and Cretaceous coal measures, in geologic periods when O2 did exceed 25%, has supported Lovelock's contention.[citation needed]

Gaia scientists see the participation of living organisms in the carbon cycle as one of the complex processes that maintain conditions suitable for life. Te only signifcant natural source of atmospheric carbon dioxide (CO2) is volcanic activity, while the only signifcant removal is through the precipitation of carbonate rocks. Carbon precipitation, solution and fxation are infuenced by the bacteria and plant roots in soils, where they improve gaseous circulation, or in coral reefs, where calcium carbonate is deposited as a solid on the sea foor. Calcium carbonate is used by living organisms to manufacture carbonaceous tests and shells. Once dead, the living organisms' shells fall to the bottom of the oceans where they generate deposits of chalk and limestone.

One of these organisms is Emiliania huxleyi, an abundant coccolithophore algae which also has a role in the formation of clouds. CO2 excess is compensated by an increase of coccolithophoride life, increasing the amount of CO2 locked in the ocean foor. Coccolithophorides increase the cloud cover, hence control the surface temperature, help cool the whole planet and favor precipitations necessary for terrestrial plants. Lately the atmospheric CO2 concentration has increased and there is some evidence that concentrations of ocean algal blooms are also increasing.

Lichen and other organisms accelerate the weathering of rocks in the surface, while the decomposition of rocks also happens faster in the soil, thanks to the activity of roots, fungi, bacteria and subterranean animals. Te fow of carbon dioxide from the atmosphere to the soil is therefore regulated with the help of living beings.

Te idea of the Earth as an integrated whole, a living being, has a long tradition. Te mythical Gaia was the primal Greek goddess personifying the Earth, the Greek version of "Mother Nature" (from Ge = Earth, and Aia = PIE grandmother), or the Earth Mother. James Lovelock gave this name to his hypothesis after a suggestion from the novelist William Golding, who was living in the same village as Lovelock at the time (Bowerchalke, Wiltshire, UK). Golding's advice was based on Gea, an alternative spelling for the name of the Greek goddess, which is used as prefx in geology, geophysics and geochemistry. Golding later made reference to Gaia in his Nobel prize acceptance speech.

460 In the eighteenth century, as geology consolidated as a modern science, James Hutton maintained that geological and biological processes are interlinked. Later, the naturalist and explorer Alexander von Humboldt recognized the coevolution of living organisms, climate, and Earth's crust. In the twentieth century, Vladimir Vernadsky formulated a theory of Earth's development that is now one of the foundations of ecology. Te Ukrainian geochemist was one of the frst scientists to recognize that the oxygen, nitrogen, and carbon dioxide in the Earth's atmosphere result from biological processes. During the 1920s he published works arguing that living organisms could reshape the planet as surely as any physical force. Vernadsky was a pioneer of the scientifc bases for the environmental sciences. His visionary pronouncements were not widely accepted in the West, and some decades later the Gaia hypothesis received the same type of initial resistance from the scientifc community.

Also in the turn to the 20th century Aldo Leopold, pioneer in the development of modern environmental ethics and in the movement for wilderness conservation, suggested a living Earth in his biocentric or holistic ethics regarding land.

It is at least not impossible to regard the earth's parts—soil, mountains, rivers, atmosphere etc,—as organs or parts of organs of a coordinated whole, each part with its defnite function. And if we could see this whole, as a whole, through a great period of time, we might perceive not only organs with coordinated functions, but possibly also that process of consumption as replacement which in biology we call metabolism, or growth. In such case we would have all the visible attributes of a living thing, which we do not realize to be such because it is too big, and its life processes too slow.

Another infuence for the Gaia hypothesis and the environmental movement in general came as a side eﬀect of the Space Race between the Soviet Union and the United States of America. During the 1960s, the frst humans in space could see how the Earth looked as a whole. Te photograph Earthrise taken by astronaut William Anders in 1968 during the Apollo 8 mission became, through the Overview Eﬀect an early symbol for the global ecology movement.

James Lovelock started defning the idea of a self-regulating Earth controlled by the community of living organisms in September 1965, while working at the Jet Propulsion Laboratory in California on methods of detecting life on Mars. Te frst paper to mention it was Planetary Atmospheres: Compositional and other Changes Associated with the Presence of Life, co-authored with C.E. Giﬃn.[39] A main concept was that life could be detected in a planetary scale by the chemical composition of the atmosphere. According to the data gathered by the Pic du Midi observatory, planets like Mars or Venus had atmospheres in chemical equilibrium. Tis diﬀerence with the Earth atmosphere was considered to be a proof that there was no life in these planets.

Lovelock formulated the Gaia Hypothesis in journal articles in 1972 and 1974, followed by a popularizing 1979 book Gaia: A new look at life on Earth. An article in the New Scientist of February 6, 1975, and a popular book length version of the hypothesis, published in 1979 as Te Quest for Gaia, began to attract scientifc and critical attention.

Lovelock called it frst the Earth feedback hypothesis, and it was a way to explain the fact that combinations of chemicals including oxygen and methane persist in stable concentrations in the atmosphere of the Earth. Lovelock suggested detecting such combinations in other planets' atmospheres as a relatively reliable and cheap way to detect life.

Later, other relationships such as sea creatures producing sulfur and iodine in approximately the same quantities as required by land creatures emerged and helped bolster the hypothesis.

In 1971 microbiologist Dr. Lynn Margulis joined Lovelock in the effort of feshing out the initial hypothesis into scientifcally proven concepts, contributing her knowledge about how microbes affect the atmosphere and the different layers in the surface of the planet. Te American biologist had also awakened criticism from the scientifc community with her theory on the origin of eukaryotic organelles and her contributions to the endosymbiotic theory, nowadays accepted. Margulis dedicated the last of eight chapters in her book, Te Symbiotic Planet, to Gaia. However, she objected to the widespread personifcation of Gaia and stressed that Gaia is "not an organism", but "an emergent property of interaction among organisms". She defned Gaia as "the series of interacting ecosystems that compose a single huge ecosystem at the Earth's surface. Period". Te book's most memorable "slogan" was actually quipped by a student of Margulis': "Gaia is just symbiosis as seen from space".

James Lovelock called his frst proposal the Gaia hypothesis but has also used the term Gaia theory. Lovelock states that the initial formulation was based on observation, but still lacked a scientifc explanation. Te Gaia hypothesis has since been supported by a number of scientifc experiments and provided a number of useful predictions. In fact, wider research proved the original hypothesis wrong, in the sense that it is not life alone but the whole Earth system that does the regulating. Ultimately God control all the regulating, tuning can alter this, if you spot something maybe you can change it for the better.

461 20) Universe and Cosmology

If your consciousness is steady and balanced then you are in the best mode for star-watching: the more you send out a balance the more you will see - like with astral travel. Te belly of the universe has all kinds of celestial treats to refect with and all types of substance. Just a a human body has a physiological body and a cosmology; as well as a psychology all of which can be felt.

Te Universe’s are all of space and time (spacetime) and its contents, which includes planets, moons, stars, galaxies, the contents of intergalactic space and all matter and energy. While the size of the entire Universe is still unknown, it is possible to measure the observable universe. As well as space and time the universe contains material, physical existence, in the form we see it fundamentally.

Te earliest scientifc models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the centre of the Universe. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the centre of the Solar System. In developing the law of universal gravitation, Sir Isaac Newton built upon Copernicus's work as well as observations by Tycho Brahe and Johannes Kepler's laws of planetary motion.

Further observational improvements led to the realization that our Solar System is located in the Milky Way galaxy, which is one of many galaxies in the Universe. It is assumed that all galaxies are diﬀerent uniformly and the diﬀerent in all directions, the Universe has an edge and a center. Discoveries in the early 20th century have suggested that the Universe had a beginning and that it is expanding at an increasing rate. Te majority of mass in the Universe appears to exist in an unknown form called dark matter. Out side the edge of this universe is inter-stellar space, or whats called the void - also existent between planets, stars, galaxies; and universes. Each universe is placed in a sector of existence; these sectors contain evolutionary parameters and universes can jump sectors if intelligence suits such a move.

Te Big Bang theory is the prevailing cosmological description of the development of the Universe. Under this theory, space and time emerged together 13.799±0.021 billion years ago[2] with a fxed amount of energy and matter that has become less dense as the Universe has expanded. After the initial expansion, the Universe cooled, allowing the frst subatomic particles to form and then simple atoms. Giant clouds later merged through gravity to form galaxies, stars, and everything else seen today. It is possible to see objects that are now further away than 13.799 billion light-years because space itself has expanded. Tis means that objects which are now 46 billion light years away can still be seen in their distant past, because at that time they were much closer to us.

Tere are many competing hypotheses about the ultimate fate of the universe and about what, if anything, preceded the Big Bang, while other physicists and philosophers refuse to speculate, doubting that information about prior states will ever be accessible. Some physicists have suggested various multiverse hypotheses, in which the Universe might be one among many universes that likewise exist.

Te Solar System[a] is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly.[b] Of those objects that orbit the Sun directly, the largest eight are the planets,[c] with the remainder being smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.[d]

462 Te Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. Te vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Jupiter. Te four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. Te four outer planets are giant planets, being substantially more massive than the terrestrials. Te two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All eight planets have almost circular orbits that lie within a nearly fat disc called the ecliptic.

Te Solar System also contains smaller objects. Te asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids. Within these populations are several dozen to possibly tens of thousands of objects large enough that they have been rounded by their own gravity. Such objects are categorized as dwarf planets. Identifed dwarf planets include the asteroid Ceres and the trans-Neptunian objects Pluto and Eris. In addition to these two regions, various other small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between regions. Six of the planets, at least four of the dwarf planets, and many of the smaller bodies are orbited by natural satellites,[f] usually termed "moons" after the Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects.

Te solar wind, a stream of charged particles fowing outwards from the Sun, creates a bubble-like region in the interstellar medium known as the heliosphere. Te heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium; it extends out to the edge of the scattered disc. Te Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. Te Solar System is located in the Orion Arm, 26,000 light-years from the center of the Milky Way.

Space: Space is the boundless three-dimensional extent in which objects and events have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. Te concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework.

Debates concerning the nature, essence and the mode of existence of space date back to antiquity; namely, to treatises like the Timaeus of Plato, or Socrates in his refections on what the Greeks called khôra (i.e. "space"), or in the Physics of Aristotle (Book IV, Delta) in the defnition of topos (i.e. place), or in the later "geometrical conception of place" as "space qua extension" in the Discourse on Place (Qawl f al-Makan) of the 11th-century Arab polymath Alhazen.[2] Many of these classical philosophical questions were discussed in the Renaissance and then reformulated in the 17th century, particularly during the early development of classical mechanics. In Isaac Newton's view, space was absolute—in the sense that it existed permanently and independently of whether there was any matter in the space. Other natural philosophers, notably Gottfried Leibniz, thought instead that space was in fact a collection of relations between objects, given by their distance and direction from one another. In the 18th century, the philosopher and theologian George Berkeley attempted to refute the "visibility of spatial depth" in his Essay Towards a New Teory of Vision. Later, the metaphysician Immanuel Kant said that the concepts of space and time are not empirical ones derived from experiences of the outside world—they are elements of an already given systematic framework that humans possess and use to structure all experiences. Kant referred to the experience of "space" in his Critique of Pure Reason as being a subjective "pure a priori form of intuition".

In the 19th and 20th centuries mathematicians began to examine geometries that are non-Euclidean, in which space is conceived as curved, rather than fat. According to Albert Einstein's theory of general relativity, space around gravitational felds deviates from Euclidean space. Experimental tests of general relativity have confrmed that non-Euclidean geometries provide a better model for the shape of space.

Time: Time is the indefnite continued progress of existence and events that occur in apparently irreversible succession from the past through the present to the future. Time is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions.

Time has long been an important subject of study in religion, philosophy, and science, but defning it in a manner applicable to all felds without circularity has consistently eluded scholars. Nevertheless, diverse felds such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems.

463 Two contrasting viewpoints on time divide prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. Te opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "fows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. Tis second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Time in physics is unambiguously operationally defned as "what a clock reads". See Units of Time. Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to defne other quantities—such as velocity—so defning time in terms of such quantities would result in circularity of defnition. An operational defnition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday aﬀairs of life. Te operational defnition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that fows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defned by measuring the electronic transition frequency of caesium atoms (see below). Time is also of signifcant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Existance:

Existence, in its most generic terms, comprises the state of being real and the ability to physically interact with the universe or multiverse. What existence is exactly is up for interpretation; and, is one of the most important and fundamental topics of ontology, the philosophical study of the nature of being, existence, or reality in general, as well as of the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology deals with questions concerning what entities exist or can be said to exist, (for instance: "Does the stellar structure UDFj-39546284 exist?"), and how such entities can be grouped, related within a hierarchy, and subdivided according to similarities and diﬀerences.

Spiritualism is the belief that the spirits of the dead have both the ability and the inclination to communicate with the living. Te afterlife, or the "spirit world", is seen by spiritualists, not as a static place, but as one in which spirits continue to evolve. Tese two beliefs: that contact with spirits is possible, and that spirits are more advanced than humans, lead spiritualists to a third belief, that spirits are capable of providing useful knowledge about moral and ethical issues, as well as about the nature of God. Some spiritualists will speak of a concept which they refer to as "spirit guides"—specifc spirits, often contacted, who are relied upon for spiritual guidance

Life is a characteristic which distinguishes objects that have self-sustaining biological processes from those that do not— either because such functions have ceased (death), or else because they lack such functions and are classifed as “inanimate".

Cosmology

Cosmology (from the Greek κόσμος, kosmos "world" and -λογία, -logia "study of") is the study of the origin, evolution, and eventual fate of the universe. Physical cosmology is the scientifc study of the universe's origin, its large-scale structures and dynamics, and its ultimate fate, as well as the scientifc laws that govern these areas.

Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology. 464 Physical cosmology is studied by scientists, such as astronomers and physicists, as well as philosophers, such as metaphysicians, philosophers of physics, and philosophers of space and time. Because of this shared scope with philosophy, theories in physical cosmology may include both scientifc and non-scientifc propositions, and may depend upon assumptions that cannot be tested. Cosmology diﬀers from astronomy in that the former is concerned with the Universe as a whole while the latter deals with individual celestial objects. Modern physical cosmology is dominated by the Big Bang theory, which attempts to bring together observational astronomy and particle physics; more specifcally, a standard parameterization of the Big Bang with dark matter and dark energy, known as the Lambda-CDM model.

Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its origin, structure, evolution, and ultimate fate. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which frst allowed us to understand those physical laws. Physical cosmology, as it is now understood, began with the development in 1915 of Albert Einstein's general theory of relativity, followed by major observational discoveries in the 1920s: frst, Edwin Hubble discovered that the universe contains a huge number of external galaxies beyond our own Milky Way; then, work by Vesto Slipher and others showed that the universe is expanding. Tese advances made it possible to speculate about the origin of the universe, and allowed the establishment of the Big Bang Teory, by Georges Lemaître, as the leading cosmological model. A few researchers still advocate a handful of alternative cosmologies; however, most cosmologists agree that the Big Bang theory explains the observations better. God said he looked and it was already there.

Dramatic advances in observational cosmology since the 1990s, including the cosmic microwave background, distant supernovae and galaxy redshift surveys, have led to the development of a standard model of cosmology. Tis model requires the universe to contain large amounts of dark matter and dark energy whose nature is currently not well understood, but the model gives detailed predictions that are in excellent agreement with many diverse observations.

Cosmology draws heavily on the work of many disparate areas of research in theoretical and applied physics. Areas relevant to cosmology include particle physics experiments and theory, theoretical and observational astrophysics, general relativity, quantum mechanics, and plasma physics.

Teoretical astrophysicist David N. Spergel has described cosmology as a "historical science" because "when we look out in space, we look back in time" due to the fnite nature of the speed of light.

Religious cosmology (also mythological cosmology) is a way of explaining the dynamic structure and order of the cosmos or universe as a process, from a religious perspective. Tis may include beliefs on origin in the form of a creation myth, subsequent evolution, current organizational form and nature, and eventual fate or destiny. Tere are various traditions in religion or religious mythology asserting how and why everything is the way it is and the signifcance of it all. Religious cosmologies describe the spatial lay-out of the universe in terms of the world in which people typically dwell as well as other dimensions, such as heaven or hell (places often believed to be above or below the earth); and, religious mythologies may include descriptions of an act or process of creation by a creator deity or a larger pantheon of deities, explanations of the transformation of chaos into order, or the assertion that existence is a matter of endless cyclical transformations. Religious cosmology diﬀers from a strictly scientifc cosmology informed by the results of the study of astronomy and similar felds, and may diﬀer in conceptualizations of the world's physical structure and place in the universe, its creation, and forecasts or predictions on its future. Te scope of religious cosmology is more inclusive than a strictly scientifc cosmology (physical cosmology) in that religious cosmology is not limited to experiential observation, testing of hypotheses, and proposals of theories; for example, religious cosmology may explain why everything is the way it is or seems to be the way it is and prescribing what humans should do in context. Variations in religious cosmology include those of Indian origin, such as Buddhism, Hindu, and Jain; the religious beliefs of China; and, the beliefs of the Abrahamic faiths, such as Judaism, Christianity, and Islam. Religious cosmologies have often developed into the formal logics of metaphysical systems, such as Platonism, Neoplatonism, Gnosticism, Daoism, Kabbalah, or the great chain of being.

Half way through this experience God tell’s us of the revelation of the 3 family’s of God, 1 Abran, 2 Demon 3 Jumar (Cluemranri) the 3 swop around every time is passed to be thriver existence is live in either space time - this one jumar- universe’s this one demon, or people this one Abran; If Abran is one tribe and one cycle is 2nx435n21n495467n2794321x417689 onms then there are 49764321976491nx439124791nf4319732149 of these tribes like the Abran- all Peace loving hippies really, cosmic!- Te Cluemranri are the 3 experiences of cosmosis separated by God the Void and his Heaven’s. We are half way through this cycle. Blessed be the Lord for this experience.

Astrophysics is the branch of astronomy that employs the principles of physics and chemistry "to ascertain the nature of the heavenly bodies, rather than their positions or motions in space." Among the objects studied are the Sun, other stars,

465 galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Teir emissions are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.

In practice, modern astronomical research often involves a substantial amount of work in the realms of theoretical and observational physics. Some areas of study for astrophysicists include their attempts to determine: the properties of dark matter, dark energy, and black holes; whether or not time travel is possible, wormholes can form, or the multiverse exists; and the origin and ultimate fate of the universe. Topics also studied by theoretical astrophysicists include: Solar System formation and evolution; stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large- scale structure of matter in the universe; origin of cosmic rays; general relativity and physical cosmology, including string cosmology and astroparticle physics.

Earth is the third planet from the Sun and the only object in the Universe known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4 billion years ago. Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in 365.26 days, a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times.

Earth's axis of rotation is tilted, producing seasonal variations on the planet's surface. Te gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earth's orientation on its axis, and gradually slows its rotation. Earth is the densest planet in the Solar System and the largest of the four terrestrial planets.

Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water, mostly by oceans. Te remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. Te majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the Earth's magnetic feld, and a convecting mantle that drives plate tectonics.

Within the frst billion years of Earth's history, life appeared in the oceans and began to aﬀect the Earth's atmosphere and surface, leading to the proliferation of aerobic and anaerobic organisms. Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earth's distance from the Sun, physical properties, and geological history have allowed life to evolve and thrive. In the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that ever lived on Earth are extinct. Estimates of the number of species on Earth today vary widely; most species have not been described. Over 7.6 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans have developed diverse societies and cultures; politically, the world has about 200 sovereign states.

Astronomy (from Greek: ἀστρονομία) is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry, in an eﬀort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, galaxies, and comets; the phenomena include supernova explosions, gamma ray bursts, and cosmic microwave background radiation. More generally, all phenomena that originate outside Earth's atmosphere are within the purview of astronomy. A related but distinct subject, physical cosmology, is concerned with the study of the Universe as a whole.

Astronomy is one of the oldest of the natural sciences. Te early civilizations in recorded history, such as the Babylonians, Greeks, Indians, Egyptians, Nubians, Iranians, Chinese, Maya, and many ancient indigenous peoples of the Americas performed methodical observations of the night sky. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy and the making of calendars, but professional astronomy is now often considered to be synonymous with astrophysics.

During the 20th century, the feld of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, which is then analyzed using basic principles of physics. Teoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. Te two felds complement each other, with theoretical astronomy seeking to explain observational results and observations being used to confrm theoretical results.

466 Astronomy is one of the few sciences where amateurs still play an active role, especially in the discovery and observation of transient phenomena. Amateur astronomers have made and contributed to many important astronomical discoveries, such as fnding new comets.

A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing. Tis produces a visible atmosphere or coma, and sometimes also a tail. Tese phenomena are due to the eﬀects of solar radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of loose collections of ice, dust, and small rocky particles. Te coma may be up to 15 times the Earth's diameter, while the tail may stretch one astronomical unit. If suﬃciently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures.

Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, which lie beyond the orbit of Neptune. Long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars and the galactic tide. Hyperbolic comets may pass once through the inner Solar System before being fung to interstellar space. Te appearance of a comet is called an apparition.

Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. Tis atmosphere has parts termed the coma (the central part immediately surrounding the nucleus) and the tail (a typically linear section consisting of dust or gas blown out from the coma by the Sun's light pressure or outstreaming solar wind plasma). However, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a diﬀerent origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System. Te discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets.

As of November 2014 there are 5,253 known comets,[5] a number that is steadily increasing as they are discovered. However, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System (in the Oort cloud) is estimated to be one trillion. Roughly one comet per year is visible to the naked eye, though many of those are faint and unspectacular. Particularly bright examples are called "great comets". Comets have been visited by unmanned probes such as the European Space Agency's Rosetta, which became the frst ever to land a robotic spacecraft on a comet, and NASA's Deep Impact, which blasted a crater on Comet Tempel 1 to study its interior.

Asteroids are minor planets, especially those of the inner Solar System. Te larger ones have also been called planetoids. Tese terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet. As minor planets in the outer Solar System were discovered and found to have volatile-based surfaces that resemble those of comets, they were often distinguished from asteroids of the asteroid belt. In this article, the term "asteroid" refers to the minor planets of the inner Solar System including those co-orbital with Jupiter.

Tere are millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets.[2] Te large majority of known asteroids orbit in the asteroid belt between the orbits of Mars and Jupiter, or are co-orbital with Jupiter (the Jupiter trojans). However, other orbital families exist with signifcant populations, including the near-Earth objects. Individual asteroids are classifed by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, and S-type. Tese were named after and are generally identifed with carbon-rich, metallic, and silicate (stony) compositions, respectively. Te size of asteroids varies greatly, the largest is almost 1,000 km (625 mi) across.

Asteroids are differentiated from comets and meteoroids. In the case of comets, the difference is one of composition: while asteroids are mainly composed of mineral and rock, comets are composed of dust and ice. In addition, asteroids formed closer to the sun, preventing the development of the aforementioned cometary ice. Te difference between asteroids and meteoroids is mainly one of size: meteoroids have a diameter of less than one meter, whereas asteroids have a diameter of greater than one meter. Finally, meteoroids can be composed of either cometary or asteroidal materials.

Only one asteroid, 4 Vesta, which has a relatively refective surface, is normally visible to the naked eye, and this only in very dark skies when it is favorably positioned. Rarely, small asteroids passing close to Earth may be visible to the naked eye for a short time. As of October 2017, the Minor Planet Center had data on almost 745,000 objects in the inner and outer Solar System, of which almost 504,000 had enough information to be given numbered designations.

467 Te United Nations declared June 30 as International Asteroid Day to educate the public about asteroids. Te date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, Russian Federation, on 30 June 1908.

A planet is an astronomical body orbiting a star or stellar remnant thatis massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals. Te term planet is ancient, with ties to history, astrology, science, mythology, and religion. Several planets in the Solar System can be seen with the naked eye. Tese were regarded by many early cultures as divine, or as emissaries of deities. As scientifc knowledge advanced, human perception of the planets changed, incorporating a number of disparate objects. In 2006, the International Astronomical Union (IAU) oﬃcially adopted a resolution defning planets within the Solar System. Tis defnition is controversial because it excludes many objects of planetary mass based on where or what they orbit. Although eight of the planetary bodies discovered before 1950 remain "planets" under the modern defnition, some celestial bodies, such as Ceres, Pallas, Juno and Vesta (each an object in the solar asteroid belt), and Pluto (the frst trans-Neptunian object discovered), that were once considered planets by the scientifc community, are no longer viewed as such.

Te planets were thought by Ptolemy to orbit Earth in deferent and epicycle motions. Although the idea that the planets orbited the Sun had been suggested many times, it was not until the 17th century that this view was supported by evidence from the frst telescopic astronomical observations, performed by Galileo Galilei. At about the same time, by careful analysis of pre-telescopic observation data collected by Tycho Brahe, Johannes Kepler found the planets' orbits were not circular but elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes, and some shared such features as ice caps and seasons. Since the dawn of the Space Age, close observation by space probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology.

Planets are generally divided into two main types: large low-density giant planets, and smaller rocky terrestrials. Under IAU defnitions, there are eight planets in the Solar System. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites.

Several thousands of planets around other stars ("extrasolar planets" or "exoplanets") have been discovered in the Milky Way. As of 1 January 2018, 3,726 known extrasolar planets in 2,792 planetary systems (including 622 multiple planetary systems), ranging in size from just above the size of the Moon to gas giants about twice as large as Jupiter have been discovered, out of which more than 100 planets are the same size as Earth, nine of which are at the same relative distance from their star as Earth from the Sun, i.e. in the habitable zone. On December 20, 2011, the Kepler Space Telescope team reported the discovery of the frst Earth-sized extrasolar planets, Kepler-20e[5] and Kepler-20f, orbiting a Sun-like star, Kepler-20.[7][8][9] A 2012 study, analyzing gravitational microlensing data, estimates an average of at least 1.6 bound planets for every star in the Milky Way. Around one in fve Sun-like stars is thought to have an Earth-sized planet in its habitable zone.

A natural satellite or moon is, in the most common usage, an astronomical body that orbits a planet or minor planet (or sometimes another small Solar System body).

In the Solar System there are six planetary satellite systems containing 175 known natural satellites. Four IAU-listed dwarf planets are also known to have natural satellites: Pluto, Haumea, Makemake, and Eris. As of October 2016, there are over 300 minor planets known to have moons.

Te Earth–Moon system is unique in that the ratio of the mass of the Moon to the mass of Earth is much greater than that of any other natural-satellite–planet ratio in the Solar System (although there are minor-planet systems with even greater ratios, notably the Pluto–Charon system). At 3,474 km (2,158 miles) across, Earth's Moon is 0.27 times the diameter of Earth.

Te Moon is an astronomical body that orbits planet Earth, being Earth's only permanent natural satellite. It is the ffth- largest natural satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits (its primary). Following Jupiter's satellite Io, the Moon is the second-densest satellite among those whose densities are known.

Te Moon is thought to have formed about 4.51 billion years ago, not long after Earth. Te most widely accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Teia.

468 Te Moon is in synchronous rotation with Earth, always showing the same face, with its near side marked by dark volcanic maria that fll the spaces between the bright ancient crustal highlands and the prominent impact craters. As seen from the Earth, it is the second-brightest regularly visible celestial object in Earth's sky, after the Sun. Its surface is actually dark, although compared to the night sky it appears very bright, with a refectance just slightly higher than that of worn asphalt. Its gravitational infuence produces the ocean tides, body tides, and the slight lengthening of the day.

Te Moon's average orbital distance at the present time is 384,402 km (238,856 mi), or 1.28 light-seconds. Tis is about thirty times the diameter of Earth, with its apparent size in the sky almost the same as that of the Sun (due to it being 400x farther and larger), resulting in the Moon covering the Sun nearly precisely in total solar eclipse. Tis matching of apparent visual size will not continue in the far future, because the Moon's distance from Earth is slowly increasing.

Te Soviet Union's Luna program was the frst to reach the Moon with unmanned spacecraft in 1959; the United States' NASA Apollo program achieved the only manned missions to date, beginning with the frst manned lunar orbiting mission by Apollo 8 in 1968, and six manned lunar landings between 1969 and 1972, with the frst being Apollo 11. Tese missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, and later history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft.

Within human culture, both the Moon's natural prominence in the earthly sky, and its regular cycle of phases as seen from the Earth have provided cultural references and infuences for human societies and cultures since time immemorial. Such cultural infuences can be found in language, lunar based calendar systems, art, and mythology.

Te Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic feld via a dynamo process.It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometers, i.e. 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System. About three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.

Te Sun is a G-type main-sequence star (G2V) based on its spectral class. As such, it is informally referred to as a yellow dwarf. It formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest fattened into an orbiting disk that became the Solar System. Te central mass became so hot and dense that it eventually initiated nuclear fusion in its core. It is thought that almost all stars form by this process.

Te Sun is roughly middle-aged; it has not changed dramatically for more than four billion years, and will remain fairly stable for more than another fve billion years. After hydrogen fusion in its core has diminished to the point at which it is no longer in hydrostatic equilibrium, the core of the Sun will experience a marked increase in density and temperature while its outer layers expand to eventually become a red giant. It is calculated that the Sun will become suﬃciently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable.

Te enormous eﬀect of the Sun on Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. Te synodic rotation of Earth and its orbit around the Sun are the basis of solar calendars, one of which is the predominant calendar in use today.

Te Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets, with the remainder being smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.

A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. Te nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fxed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes.

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime, and for some stars by supernova nucleosynthesis

469 when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively. Te total mass of a star is the main factor that determines its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment aﬀects its rotation and movement. A plot of the temperature of many stars against their luminosities produces a plot known as a Hertzsprung–Russell diagram (H–R diagram). Plotting a particular star on that diagram allows the age and evolutionary state of that star to be determined.

A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. When the stellar core is suﬃciently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. Te remainder of the star's interior carries energy away from the core through a combination of radiative and convective heat transfer processes. Te star's internal pressure prevents it from collapsing further under its own gravity. A star with mass greater than 0.4 times the Sun's will expand to become a red giant when the hydrogen fuel in its core is exhausted. In some cases, it will fuse heavier elements at the core or in shells around the core. As the star expands it throws a part of its mass, enriched with those heavier elements, into the interstellar environment, to be recycled later as new stars. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or if it is suﬃciently massive a black hole.

Binary and multi-star systems consist of two or more stars that are gravitationally bound and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a signifcant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.

Te Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. Te vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Jupiter. Te four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. Te four outer planets are giant planets, being substantially more massive than the terrestrials. Te two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All eight planets have almost circular orbits that lie within a nearly fat disc called the ecliptic.

Te Solar System also contains smaller objects. Te asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids. Within these populations are several dozen to possibly tens of thousands of objects large enough that they have been rounded by their own gravity. Such objects are categorized as dwarf planets. Identifed dwarf planets include the asteroid Ceres and the trans-Neptunian objects Pluto and Eris. In addition to these two regions, various other small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between regions. Six of the planets, at least four of the dwarf planets, and many of the smaller bodies are orbited by natural satellites, usually termed "moons" after the Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects.

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. Te word galaxy is derived from the Greek galaxias

(γαλαξίας), literally "milky", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million (108) stars to giants with one hundred trillion (1014) stars, each orbiting its galaxy's center of mass.

Galaxies are categorized according to their visual morphology as elliptical, spiral, or irregular. Many galaxies are thought to have black holes at their active centers. Te Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As of March 2016, GN-z11 is the oldest and most distant observed galaxy with a comoving distance of 32 billion light-years from Earth, and observed as it existed just 400 million years after the Big Bang.

470 Recent estimates of the number of galaxies in the observable universe range from 200 billion (2×1011) to 2 trillion (2×1012) or more, containing more stars than all the grains of sand on planet Earth. Most of the galaxies are 1,000 to 100,000 parsecs in diameter and separated by distances on the order of millions of parsecs (or megaparsecs).

Te space between galaxies is flled with a tenuous gas having an average density of less than one atom per cubic meter. Te majority of galaxies are gravitationally organized into groups, clusters, and superclusters. At the largest scale, these associations are generally arranged into sheets and flaments surrounded by immense voids. Te largest structure of galaxies yet recognised is a cluster of superclusters that has been named Laniakea.

Intergalactic space is the physical space between galaxies. Studies of the large scale distribution of galaxies show that the Universe has a foam-like structure, with clusters and groups of galaxies lying along flaments that occupy about a tenth of the total space. Te remainder forms huge voids that are mostly empty of galaxies. Typically, a void spans a distance of (10–40) h−1 Mpc, where h is the Hubble constant in units of 100 km s−1 Mpc−1.

Surrounding and stretching between galaxies, there is a rarefed plasma that is organized in a galactic flamentary structure. Tis material is called the intergalactic medium (IGM). Te density of the IGM is 5–200 times the average density of the Universe. It consists mostly of ionized hydrogen; i.e. a plasma consisting of equal numbers of electrons and protons. As gas falls into the intergalactic medium from the voids, it heats up to temperatures of 105 K to 107 K, which is high enough so that collisions between atoms have enough energy to cause the bound electrons to escape from the hydrogen nuclei; this is why the IGM is ionized. At these temperatures, it is called the warm–hot intergalactic medium (WHIM). (Although the plasma is very hot by terrestrial standards, 105 K is often called "warm" in astrophysics.) Computer simulations and observations indicate that up to half of the atomic matter in the Universe might exist in this warm–hot, rarefed state. When gas falls from the flamentary structures of the WHIM into the galaxy clusters at the intersections of the cosmic flaments, it can heat up even more, reaching temperatures of 108 K and above in the so-called intracluster medium.

Te Milky Way is the galaxy that contains our Solar System. Te descriptive "milky" is derived from the appearance from Earth of the galaxy – a band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. Te term Milky Way is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle"). From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei frst resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis,observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.

Te Milky Way is a barred spiral galaxy with a diameter between 100,000 and 180,000 light-years (ly). Te Milky Way is estimated to contain 100–400 billion stars. Tere are probably at least 100 billion planets in the Milky Way. Te Solar System is located within the disk, about 26,000 light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. Te stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. Te very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole.

Stars and gases at a wide range of distances from the Galactic Center orbit at approximately 220 kilometers per second. Te constant rotation speed contradicts the laws of Keplerian dynamics and suggests that much of the mass of the Milky Way does not emit or absorb electromagnetic radiation. Tis mass has been termed "dark matter". Te rotational period is about 240 million years at the position of the Sun. Te Milky Way as a whole is moving at a velocity of approximately 600 km per second with respect to extragalactic frames of reference. Te oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of the Big Bang.

Te Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which is a component of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster.

Te Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group.

Tere are 59 small galaxies confrmed to be within 420 kiloparsecs (1.4 million light-years) of the Milky Way, but not all of them are necessarily in orbit, and some may themselves be in orbit of other satellite galaxies. Te only ones visible to the naked eye are the Large and Small Magellanic Clouds, which have been observed since prehistory. Measurements with the Hubble Space Telescope in 2006 suggest the Magellanic Clouds may be moving too fast to be orbiting the Milky Way. Of

471 the galaxies confrmed to be in orbit, the largest is the Sagittarius Dwarf Elliptical Galaxy, which has a diameter of 2.6 kiloparsecs (8,500 ly) or roughly a ffth that of the Milky Way.

Te Local Group is the galaxy group that includes the Milky Way. Te Local Group comprises more than 54 galaxies, most of them dwarf galaxies. Its gravitational center is located somewhere between the Milky Way and the Andromeda Galaxy. Te Local Group has a diameter of 10 Mly (3.1 Mpc) (about 1023 meters) and has a binary (dumbbell)[1] distribution. Te group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster.

Te three largest members of the group (in decreasing order) are the Andromeda Galaxy, the Milky Way and the Triangulum Galaxy. Te larger two of these spiral galaxies each have their own system of satellite galaxies.

Te Andromeda Galaxy's satellite system consists of Messier 32 (M32), Messier 110 (M110), NGC 147, NGC 185, Andromeda I (And I), And II, And III, And V, And VI (also known as Pegasus Dwarf Spheroidal Galaxy, or Pegasus DSph), And VII (also known as Cassiopeia Dwarf Galaxy), And VIII, And IX, And X, And XI, And XIX, And XXI and And XXII, plus several additional ultra-faint dwarf spheroidal galaxies.[citation needed] Milky Way's satellite galaxies system comprises Sagittarius Dwarf Galaxy, Large Magellanic Cloud, Small Magellanic Cloud, Canis Major Dwarf Galaxy (disputed, considered by some not a galaxy), Ursa Minor Dwarf Galaxy, Draco Dwarf Galaxy, Carina Dwarf Galaxy, Sextans Dwarf Galaxy, Sculptor Dwarf Galaxy, Fornax Dwarf Galaxy, Leo I (a dwarf galaxy), Leo II (a dwarf galaxy), and Ursa Major I Dwarf Galaxy and Ursa Major II Dwarf Galaxy, plus several additional ultra-faint dwarf spheroidal galaxies.

Te Triangulum Galaxy may or may not be a companion to the Andromeda Galaxy. Pisces Dwarf Galaxy is equidistant from the Andromeda Galaxy and the Triangulum Galaxy, so it may be a satellite of either. Te membership of NGC 3109, with its companions Sextans A and the Antlia Dwarf Galaxy, is uncertain due to extreme distances from the center of the Local Group.

Te other members of the group are likely gravitationally secluded from these large subgroups: IC 10, IC 1613, Phoenix Dwarf Galaxy, Leo A, Tucana Dwarf Galaxy, Cetus Dwarf Galaxy, Pegasus Dwarf Irregular Galaxy, Wolf–Lundmark– Melotte, Aquarius Dwarf Galaxy, and Sagittarius Dwarf Irregular Galaxy.

Te Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galaxies that contains the Virgo Cluster in addition to the Local Group, which in turn contains the Milky Way and Andromeda galaxies. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years). It is one of about 10 million superclusters in the observable universe.

A 2014 study indicates that the Virgo Supercluster is only a lobe of an even greater supercluster, Laniakea—a larger, competing referent of Local Supercluster— which is centered on the Great Attractor.

Te Laniakea Supercluster (Laniakea; also called Local Supercluster or Local SCl or sometimes Lenakaeia) is the galaxy supercluster that is home to the Milky Way and approximately 100,000 other nearby galaxies. It was defned in September 2014, when a group of astronomers including R. Brent Tully of the University of Hawaii and Hélène Courtois of the University of Lyon published a new way of defning superclusters according to the relative velocities of galaxies. Te new defnition of the local supercluster subsumes the prior defned local supercluster, the Virgo Supercluster, as an appendage.

Follow-up studies suggest that Laniakea is not gravitationally bound; it will disperse rather than continue to maintain itself as an overdensity relative to surrounding areas.

A nebula (Latin for "cloud" or "fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud and dust, hydrogen, helium and other ionized gases. Originally, nebula was a name for any diﬀuse astronomical object, including galaxies beyond the Milky Way. Te Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confrmed in the early 20th century by Vesto Slipher, Edwin Hubble and others.

Most nebulae are of vast size, some are hundreds of light years in diameter. Contrary to fctional depictions where starships hide in nebulae as thick as cloud banks, in reality a nebula that is barely visible to the human eye from Earth would appear larger, but no brighter, from close by. Te Orion Nebula, the brightest nebula in the sky that occupies a region twice the diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms. Many nebulae are visible due to their fuorescence caused by the

472 embedded hot stars, while others are so diﬀuse they can only be detected with long exposures and special flters. Some nebulae are variably illuminated by T Tauri variable stars. Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter, and eventually will become dense enough to form stars. Te remaining material is then believed to form planets and other planetary system objects.

Te Universe is all of space and time (spacetime) and its contents, which includes planets, moons, stars, galaxies, the contents of intergalactic space and all matter and energy. While the size of the entire Universe is still unknown, it is possible to measure the observable universe.

Te cosmic microwave background (CMB, CMBR) is electromagnetic radiation as a remnant from an early stage of the universe in Big Bang cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or "relic radiation". Te CMB is a faint cosmic background radiation flling all space that is an important source of data on the early universe because it is the oldest electromagnetic radiation in the universe, dating to the epoch of recombination. With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a suﬃciently sensitive radio telescope shows a faint background noise, or glow, almost isotropic, that is not associated with any star, galaxy, or other object. Tis glow is strongest in the microwave region of the radio spectrum. Te accidental discovery of the CMB in 1964 by American radio astronomers Arno Penzias and Robert Wilson[1][2] was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize in Physics.

Te discovery of CMB is landmark evidence of the Big Bang origin of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and flled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation flling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral hydrogen atoms. Unlike the uncombined protons and electrons, these newly conceived atoms could not absorb the thermal radiation, and so the universe became transparent instead of being an opaque fog.[3] Cosmologists refer to the time period when neutral atoms frst formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling. Te photons that existed at the time of photon decoupling have been propagating ever since, though growing fainter and less energetic, since the expansion of space causes their wavelength to increase over time (and wavelength is inversely proportional to energy according to Planck's relation). Tis is the source of the alternative term relic radiation. Te surface of last scattering refers to the set of points in space at the right distance from us so that we are now receiving photons originally emitted from those points at the time of photon decoupling.

Precise measurements of the CMB are critical to cosmology, since any proposed model of the universe must explain this radiation. Te CMB has a thermal black body spectrum at a temperature of 2.72548±0.00057 K.[4] Te spectral radiance dEν/dν peaks at 160.23 GHz, in the microwave range of frequencies, corresponding to a photon energy of about 6.626 × 10−4 eV. Alternatively, if spectral radiance is defned as dEλ/dλ, then the peak wavelength is 1.063 mm (282 GHz, 1.168 x 10−3 eV photons). Te glow is very nearly uniform in all directions, but the tiny residual variations show a very specifc pattern, the same as that expected of a fairly uniformly distributed hot gas that has expanded to the current size of the universe. In particular, the spectral radiance at diﬀerent angles of observation in the sky contains small anisotropies, or irregularities, which vary with the size of the region examined. Tey have been measured in detail, and match what would be expected if small thermal variations, generated by quantum fuctuations of matter in a very tiny space, had expanded to the size of the observable universe we see today. Tis is a very active feld of study, with scientists seeking both better data (for example, the Planck spacecraft) and better interpretations of the initial conditions of expansion. Although many diﬀerent processes might produce the general form of a black body spectrum, no 473 model other than the Big Bang has yet explained the fuctuations. As a result, most cosmologists consider the Big Bang model of the universe to be the best explanation for the CMB.

Te high degree of uniformity throughout the observable universe and its faint but measured anisotropy lend strong support for the Big Bang model in general and the ΛCDM ("Lambda Cold Dark Matter") model in particular. Moreover, the fuctuations are coherent on angular scales that are larger than the apparent cosmological horizon at recombination. Either such coherence is acausally fne-tuned, or cosmic infation occurred.[5][6]

Te Big Bang theory is the prevailing cosmological description of the development of the Universe. Under this theory, space and time emerged together 13.799±0.021 billion years ago with a fxed amount of energy and matter that has become less dense as the Universe has expanded. After the initial expansion, the Universe cooled, allowing the frst subatomic particles to form and then simple atoms. Giant clouds later merged through gravity to form galaxies, stars, and everything else seen today. It is possible to see objects that are now further away than 13.799 billion light-years because space itself has expanded. Tis means that objects which are now 46 billion light years away can still be seen in their distant past, because at that time they were much closer to us.

A pulsar (from pulse and -ar as in quasar) is a highly magnetized, rotating neutron star or white dwarf, that emits a beam of electromagnetic radiation. Tis radiation can be observed only when the beam of emission is pointing toward Earth (much like the way a lighthouse can be seen only when the light is pointed in the direction of an observer), and is responsible for the pulsed appearance of emission. Neutron stars are very dense, and have short, regular rotational periods. Tis produces a very precise interval between pulses that range from milliseconds to seconds for an individual pulsar. Pulsars are believed to be one of the candidates of the observed ultra-high-energy cosmic rays (see also centrifugal mechanism of acceleration).

Te precise periods of pulsars make them very useful tools. Observations of a pulsar in a binary neutron star system were used to indirectly confrm the existence of gravitational radiation. Te frst extrasolar planets were discovered around a pulsar, PSR B1257+12. Certain types of pulsars rival atomic clocks in their accuracy in keeping time.

A neutron star is the collapsed core of a large star which before collapse had a total of between 10 and 29 solar masses. Neutron stars are the smallest and densest stars known to exist. Tough neutron stars typically have a radius on the order of 10 kilometres (6.2 mi), they can have masses of about twice that of the Sun. Tey result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past the white dwarf star density to that of atomic nuclei. Once formed, they no longer actively generate heat, and cool over time; however, they may still evolve further through collision or accretion. Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons (subatomic particles with no net electrical charge and with slightly larger mass than protons); the electrons and protons present in normal matter combine to produce neutrons at the conditions in a neutron star. Neutron stars are supported against further collapse by neutron degeneracy pressure, a phenomenon described by the Pauli exclusion principle, just as white dwarfs are supported against collapse by electron degeneracy pressure. If the remnant star has a mass greater than about 3 solar masses, it continues collapsing to form a black hole.

Neutron stars that can be observed are very hot and typically have a surface temperature of around 600000 K. Tey are so dense that a normal-sized matchbox containing neutron-star material would have a mass of approximately 3 billion tonnes, or a 0.5 cubic kilometre chunk of the Earth (a cube with edges of about 800 metres). Teir magnetic felds are between 108 and 1015 (100 million to 1 quadrillion) times as strong as that of the Earth. Te gravitational feld at the neutron star's surface is about 2×1011 (200 billion) times that of the Earth.

As the star's core collapses, its rotation rate increases as a result of conservation of angular momentum, hence newly formed neutron stars rotate at up to several hundred times per second. Some neutron stars emit beams of electromagnetic radiation that make them detectable as pulsars. Indeed, the discovery of pulsars by Jocelyn Bell Burnell in 1967 was the frst observational suggestion that neutron stars exist. Te radiation from pulsars is thought to be primarily emitted from regions near their magnetic poles. If the magnetic poles do not coincide with the rotational axis of the neutron star, the emission beam will sweep the sky, and when seen from a distance, if the observer is somewhere in the path of the beam, it will appear as pulses of radiation coming from a fxed point in space (the so- called "lighthouse eﬀect"). Te fastest-spinning neutron

474 star known is PSR J1748-2446ad, rotating at a rate of 716 times a second or 43,000 revolutions per minute, giving a linear speed at the surface on the order of 0.24 c (i.e. nearly a quarter the speed of light).

Tere are thought to be around 100 million neutron stars in the Milky Way, a fgure obtained by estimating the number of stars that have undergone supernova explosions. However, most are old and cold, and neutron stars can only be easily detected in certain instances, such as if they are a pulsar or part of a binary system. Slow-rotating and non-accreting neutron stars are almost undetectable; however, since the Hubble Space Telescope detection of RX J185635-3754, a few nearby neutron stars that appear to emit only thermal radiation have been detected. Soft gamma repeaters are conjectured to be a type of neutron star with very strong magnetic felds, known as magnetars, or alternatively, neutron stars with fossil disks around them.

Neutron stars in binary systems can undergo accretion which typically makes the system bright in X-rays while the material falling onto the neutron star can form hotspots that rotate in and out of view in identifed X-ray pulsar systems. Additionally, such accretion can "recycle" old pulsars and potentially cause them to gain mass and spin-up to very fast rotation rates, forming the so-called millisecond pulsars. Tese binary systems will continue to evolve, and eventually the companions can become compact objects such as white dwarfs or neutron stars themselves, though other possibilities include a complete destruction of the companion through ablation or merger. Te merger of binary neutron stars may be the source of short-duration gamma-ray bursts and are likely strong sources of gravitational waves. In 2017, a direct detection (GW170817) of the gravitational waves from such an event was made, and gravitational waves have also been indirectly detected in a system where two neutron stars orbit each other.

Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.

A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H2). Tis is in contrast to other areas of the interstellar medium that contain predominantly ionized gas.

Molecular hydrogen is diﬃcult to detect by infrared and radio observations, so the molecule most often used to determine the presence of H2 is carbon monoxide (CO). Te ratio between CO luminosity and H2 mass is thought to be constant, although there are reasons to doubt this assumption in observations of some other galaxies.

Within molecular clouds are regions with higher density, where lots of dust and gas cores reside, called clumps. Tese clumps are the beginning of star formation, if gravity can overcome the high density and force the dust and gas to collapse.

A vast assemblage of molecular gas with a mass of approximately 103 to 107 times the mass of the Sun is called a giant molecular cloud (GMC). GMCs are around 15 to 600 light-years in diameter (5 to 200 parsecs). Whereas the average density in the solar vicinity is one particle per cubic centimetre, the average density of a GMC is a hundred to a thousand times as great. Although the Sun is much more dense than a GMC, the volume of a GMC is so great that it contains much more mass than the Sun. Te substructure of a GMC is a complex pattern of flaments, sheets, bubbles, and irregular clumps.

Te densest parts of the flaments and clumps are called "molecular cores", while the densest molecular cores are called "dense molecular cores" and have densities in excess of 104 to 106 particles per cubic centimeter. Observationally, typical molecular cores are traced with CO and dense molecular cores are traced with ammonia. Te concentration of dust within molecular cores is normally suﬃcient to block light from background stars so that they appear in silhouette as dark nebulae.

GMCs are so large that "local" ones can cover a signifcant fraction of a constellation; thus they are often referred to by the name of that constellation, e.g. the Orion Molecular Cloud (OMC) or the Taurus Molecular Cloud (TMC). Tese local GMCs are arrayed in a ring in the neighborhood of the Sun coinciding with the Gould Belt. Te most massive collection of molecular clouds in the galaxy forms an asymmetrical ring about the galactic center at a radius of 120 parsecs; the largest component of this ring is the Sagittarius B2 complex. Te Sagittarius region is chemically rich and is often used as an exemplar by astronomers searching for new molecules in interstellar space.

475 Isolated gravitationally-bound small molecular clouds with masses less than a few hundred times that of the Sun are called Bok globules. Te densest parts of small molecular clouds are equivalent to the molecular cores found in GMCs and are often included in the same studies.

In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy. Tis matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It flls interstellar space and blends smoothly into the surrounding intergalactic space. Te energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation feld.

Te interstellar medium is composed of multiple phases, distinguished by whether matter is ionic, atomic, or molecular, and the temperature and density of the matter. Te interstellar medium is composed primarily of hydrogen followed by helium with trace amounts of carbon, oxygen, and nitrogen comparatively to hydrogen. Te thermal pressures of these phases are in rough equilibrium with one another. Magnetic felds and turbulent motions also provide pressure in the ISM, and are typically more important dynamically than the thermal pressure is.

In all phases, the interstellar medium is extremely tenuous by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diﬀuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber. By mass, 99% of the ISM is gas in any form, and 1% is dust. Of the gas in the ISM, by number 91% of atoms are hydrogen and 9% are helium, with 0.1% being atoms of elements heavier than hydrogen or helium,[3] known as "metals" in astronomical parlance. By mass this amounts to 70% hydrogen, 28% helium, and 1.5% heavier elements. Te hydrogen and helium are primarily a result of primordial nucleosynthesis, while the heavier elements in the ISM are mostly a result of enrichment in the process of stellar evolution.

Te ISM plays a crucial role in astrophysics precisely because of its intermediate role between stellar and galactic scales. Stars form within the densest regions of the ISM, molecular clouds, and replenish the ISM with matter and energy through planetary nebulae, stellar winds, and supernovae. Tis interplay between stars and the ISM helps determine the rate at which a galaxy depletes its gaseous content, and therefore its lifespan of active star formation.

Voyager 1 reached the ISM on August 25, 2012, making it the frst artifcial object from Earth to do so. Interstellar plasma and dust will be studied until the mission's end in 2025.

In astronomy, Bok globules are isolated and relatively small dark nebulae, containing dense cosmic dust and gas from which star formation may take place. Bok globules are found within H II regions, and typically have a mass of about 2[1] to 50 solar masses contained within a region about a light year or so across (about 4.5×1047 m3). Tey contain molecular hydrogen (H2), carbon oxides and helium, and around 1% (by mass) silicate dust. Bok globules most commonly result in the formation of double- or multiple-star systems.

Bok globules were frst observed by astronomer Bart Bok in the 1940s. In an article published in 1947, he and Edith Reilly hypothesized that these clouds were "similar to insect's cocoons" that were undergoing gravitational collapse to form new stars, from which stars and star clusters were born. Tis hypothesis was diﬃcult to verify due to the observational diﬃculties of establishing what was happening inside a dense dark cloud that obscured all visible light emitted from within it. An analysis of near-infrared observations published in 1990 confrmed that stars were being born inside Bok globules. Further observations have revealed that some Bok globules contain embedded warm sources, some contain Herbig–Haro objects, and some show outfows of molecular gas. Millimeter- wave emission line studies have provided evidence for the infall of material onto an accreting protostar. It is now thought that a typical Bok globule contains about 10 solar masses of material in a region about a light-year or so across, and that Bok globules most commonly result in the formation of double- or multiple-star systems.

Bok globules are still a subject of intense research. Known to be some of the coldest objects in the natural universe, their structure and density remains somewhat a mystery. Methods applied so far have relied on column density derived from near- infrared extinction and even star counting in a bid to probe these objects further.

Bok globules that are irradiated by ultraviolet light from hot nearby stars exhibit stripping of materials to produce a tail. Tese types are called "cometary globules" (CG).

A dark nebula or absorption nebula is a type of interstellar cloud that is so dense that it obscures the light from objects behind it, such as background stars and emission or refection nebulae. Te extinction of the light is caused by interstellar dust grains located in the coldest, densest parts of larger[clarifcation needed] molecular clouds. Clusters and large complexes

476 of dark nebulae are associated with Giant Molecular Clouds. Isolated small dark nebulae are called Bok globules. Like other interstellar dust or material, things it obscures are only visible using radio waves in radio astronomy or infrared in infrared astronomy.

Dark clouds appear so because of sub-micrometre-sized dust particles, coated with frozen carbon monoxide and nitrogen, which eﬀectively block the passage of light at visible wavelengths. Also present are molecular hydrogen, atomic helium, C18O (CO with oxygen as the 18O isotope), CS, NH3 (ammonia), H2CO (formaldehyde), c-C3H2 (cyclopropenylidene) and a molecular ion N2H+ (diazenylium), all of which are relatively transparent. Tese clouds are the spawning grounds of stars and planets, and understanding their development is essential to understanding star formation.

Te form of such dark clouds is very irregular: they have no clearly defned outer boundaries and sometimes take on convoluted serpentine shapes. Te largest dark nebulae are visible to the naked eye, appearing as dark patches against the brighter background of the Milky Way like the Coalsack Nebula and the Great Rift. Tese naked-eye objects are sometimes known as dark cloud constellations and take on a variety of names.

In the inner outer molecular regions of dark nebulae, important events take place, such as the formation of stars and masers.

Young stellar object (YSO) denotes a star in its early stage of evolution. Tis class consists of two groups of objects: protostars and pre-main-sequence stars.

A protostar is a very young star that is still gathering mass from its parent molecular cloud. Te protostellar phase is the earliest one in the process of stellar evolution. For a one solar-mass star it lasts about 1,000,000 years. Te phase begins when a molecular cloud frst collapses under the force of self-gravity. It ends when the protostar blows back the infalling gas and is revealed as an optically visible pre-main-sequence star, which later contracts to become a main sequence star.

In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. Tese color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main- sequence stars or "dwarf" stars. Tese are the most numerous true stars in the universe, and include the Earth's Sun.

After condensation of mass and ignition of a star, it generates thermal energy in the dense core region through nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. Te strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. Te energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.

Te main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (1.5 M☉) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain.

Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main- sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.

In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. Te behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.

T Tauri stars (TTS) are a class of variable stars named after their prototype – T Tauri. Tey are found near molecular clouds and identifed by their optical variability and strong chromospheric lines. T Tauri stars are pre-main-sequence stars in the process of contracting to the main sequence along the Hayashi track, a luminosity–temperature relationship obeyed by

477 infant stars of less than 3 solar masses (M☉) in the pre-main-sequence phase of stellar evolution. It ends when a star of 0.5 M☉ develops a radiative zone, or when a larger star commences nuclear fusion on the main sequence.

A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence. Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope of interstellar dust and gas. After the protostar blows away this envelope, it is optically visible, and appears on the stellar birthline in the Hertzsprung-Russell diagram. At this point, the star has acquired nearly all of its mass but has not yet started hydrogen burning (i.e. nuclear fusion of hydrogen). Te star then contracts, its internal temperature rising until it begins hydrogen burning on the zero age main sequence. Tis period of contraction is the pre-main sequence stage. An observed PMS object can either be a T Tauri star, if it has fewer than 2 solar masses (M☉), or else a Herbig Ae/Be star, if it has 2 to 8 M☉. Yet more massive stars have no pre-main-sequence stage because they contract too quickly as protostars. By the time they become visible, the hydrogen in their centers is already fusing and they are main-sequence objects.

Te energy source of PMS objects is gravitational contraction, as opposed to hydrogen burning in main-sequence stars. In the Hertzsprung–Russell diagram, pre- main-sequence stars with more than 0.5 M☉ frst move vertically downward along Hayashi tracks, then leftward and horizontally along Henyey tracks, until they fnally halt at the main sequence. Pre-main- sequence stars with less than 0.5 M☉ contract vertically along the Hayashi track for their entire evolution.

PMS stars can be diﬀerentiated empirically from main-sequence stars by using stellar spectra to measure their surface gravity. A PMS object has a larger radius than a main-sequence star with the same stellar mass and thus has a lower surface gravity. Although they are optically visible, PMS objects are rare relative to those on the main sequence, because their contraction lasts for only 1 percent of the time required for hydrogen fusion. During the early portion of the PMS stage, most stars have circumstellar disks, which are the sites of planet formation.

A Herbig Ae/Be star (HAeBe) is a pre-main-sequence star – a young (<10Myr) star of spectral types A or B. Tese stars are still embedded in gas-dust envelopes and are sometimes accompanied by circumstellar disks.[1] Hydrogen and calcium emission lines are observed in their spectra. Tey are 2-8 Solar mass (M☉) objects, still existing in the star formation (gravitational contraction) stage and approaching the main sequence (i.e. they are not burning hydrogen in their center). In the Hertzsprung–Russell diagram these stars are located to the right of the main sequence. Tey are named after the American astronomer George Herbig, who frst distinguished them from other stars in 1960. Te original Herbig criteria were:

Spectral type earlier than F0 (in order to exclude T Tauri stars), Balmer emission lines in the stellar spectrum (in order to be similar to T Tauri stars), Projected location within the boundaries of a dark interstellar cloud (in order to select really young stars near their birthplaces),Illumination of a nearby bright refection nebula (in order to guarantee physical link with star formation region). Tere are now several known isolated Herbig Ae/Be stars (i.e. not connected with dark clouds or nebulae). Tus the most reliable criteria now can be:

Spectral type earlier than F0, Balmer emission lines in the stellar spectrum, Infrared radiation excess (in comparison with normal stars) due to circumstellar dust (in order to distinguish from classical Be stars, which have infrared excess due to free-free emission). Sometimes Herbig Ae/Be stars show signifcant brightness variability. Tey are believed to be due to clumps (protoplanets and planetesimals) in the circumstellar disk. In the lowest brightness stage the radiation from the star becomes bluer and linearly polarized (when the clump obscures direct star light, scattered from disk light relatively increases – it is the same eﬀect as the blue color of our sky).

Analogs of Herbig Ae/Be stars in the smaller mass range (<2 M☉) – F, G, K, M spectral type pre-main-sequence stars – are called T Tauri stars. More massive

(>8 M☉) stars in pre-main-sequence stage are not observed, because they evolve very quickly: when they become visible (i.e. disperses surrounding circumstellar gas and dust cloud), the hydrogen in the center is already burning and they are main- sequence objects.

Herbig–Haro (HH) objects are small patches of nebulosity associated with newly born stars, and are formed when narrow jets of partially ionized gas ejected by those stars collide with nearby clouds of gas and dust at speeds of several hundred

478 kilometres per second. Herbig–Haro objects are ubiquitous in star-forming regions, and several are often seen around a single star, aligned with its rotational axis.

HH objects are transient phenomena that last less than a few thousand years. Tey can evolve visibly over quite short astronomical timescales as they move rapidly away from their parent star into the gas clouds of interstellar space (the interstellar medium or ISM). Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a few years, as parts of the nebula fade while others brighten as they collide with clumpy material of the interstellar medium.

Te objects were frst observed in the late 19th century by Sherburne Wesley Burnham, but were not recognised as being a distinct type of emission nebula until the 1940s. Te frst astronomers to study them in detail were George Herbig and Guillermo Haro, after whom they have been named. Herbig and Haro were working independently on studies of star formation when they frst analysed the objects, and recognised that they were a by-product of the star formation process.

In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.

A few hundred thousand years after the Big Bang, the Universe cooled to the point where atoms could form. As the Universe continued to expand and cool, the atoms lost enough kinetic energy, and dark matter coalesced suﬃciently, to form protogalaxies. As further accretion occurred, galaxies formed. Indirect evidence is widespread. Galaxies grow through mergers and smooth gas accretion. Accretion also occurs inside galaxies, forming stars.

In astronomy, the initial mass function (IMF) is an empirical function that describes the distribution of initial masses for a population of stars. Te IMF is often given as a probability distribution function (PDF) for the mass at which a star enters the main sequence (begins hydrogen fusion). In astronomy, the initial mass function (IMF) is an empirical function that describes the distribution of initial masses for a population of stars. Te IMF is often given as a probability distribution function (PDF) for the mass at which a star enters the main sequence (begins hydrogen fusion). Te distribution function can then be used to construct the mass distribution (the histogram of stellar masses) of a population of stars. Te properties and evolution of a star are closely related to its mass, so the IMF is an important diagnostic tool for astronomers studying large quantities of stars. For example, the initial mass of a star is the primary factor determining its colour, luminosity, and lifetime.

Te Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. Te cooling causes the pressure to drop, and the star or planet shrinks as a result. Tis compression, in turn, heats the core of the star/planet. Tis mechanism is evident on Jupiter and Saturn and on brown dwarfs whose central temperatures are not high enough to undergo nuclear fusion. It is estimated that Jupiter radiates more energy through this mechanism than it receives from the Sun, but Saturn might not. Te latter process causes Jupiter to shrink at a rate of two centimetres each year.

Te mechanism was originally proposed by Kelvin and Helmholtz in the late 19th century to explain the source of energy of the Sun. By the mid-19th century, conservation of energy had been accepted, and one consequence of this law of physics is that the Sun must have some energy source to continue to shine. Because nuclear reactions were unknown, the main candidate for the source of solar energy was gravitational contraction.

However, it soon was recognized by Sir Arthur Eddington and others that the total amount of energy available through this mechanism only allowed the Sun to shine for millions of years rather than the billions of years that the geological and biological evidence suggested for the age of the Earth. (Kelvin himself had argued that the Earth was millions, not billions, of years old.) Te true source of the Sun's energy remained uncertain until the 1930s, when it was shown by Hans Bethe to be nuclear fusion.

Te nebular hypothesis is the most widely accepted model in the feld of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests that the Solar System formed from nebulous material. Te theory was developed by Immanuel Kant and published in his Allgemeine Naturgeschichte und Teorie des Himmels ("Universal Natural History and Teory of the Heavens"), published in 1755. Originally applied to the Solar System, the process of planetary system formation is now thought to be at work throughout the Universe.[1] Te widely accepted modern variant of the nebular hypothesis is the solar nebular disk model (SNDM) or solar nebular model. It oﬀered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the nebular hypothesis are echoed in modern theories of planetary formation, but most elements have been superseded.

479 According to the nebular hypothesis, stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC). Tese clouds are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. Star formation is a complex process, which always produces a gaseous protoplanetary disk, proplyd, around the young star. Tis may give birth to planets in certain circumstances, which are not well known. Tus the formation of planetary systems is thought to be a natural result of star formation. A Sun-like star usually takes approximately 1 million years to form, with the protoplanetary disk evolving into a planetary system over the next 10–100 million years.

Te protoplanetary disk is an accretion disk that feeds the central star. Initially very hot, the disk later cools in what is known as the T tauri star stage; here, formation of small dust grains made of rocks and ice is possible. Te grains eventually may coagulate into kilometer-sized planetesimals. If the disk is massive enough, the runaway accretions begin, resulting in the rapid—100,000 to 300,000 years—formation of Moon- to Mars-sized planetary embryos. Near the star, the planetary embryos go through a stage of violent mergers, producing a few terrestrial planets. Te last stage takes approximately 100 million to a billion years.

Te formation of giant planets is a more complicated process. It is thought to occur beyond the frost line, where planetary embryos mainly are made of various types of ice. As a result, they are several times more massive than in the inner part of the protoplanetary disk. What follows after the embryo formation is not completely clear. Some embryos appear to continue to grow and eventually reach 5–10 Earth masses—the threshold value, which is necessary to begin accretion of the hydrogen– helium gas from the disk. Te accumulation of gas by the core is initially a slow process, which continues for several million years, but after the forming protoplanet reaches about 30 Earth masses (M⊕) it accelerates and proceeds in a runaway manner. Jupiter- and Saturn-like planets are thought to accumulate the bulk of their mass during only 10,000 years. Te accretion stops when the gas is exhausted. Te formed planets can migrate over long distances during or after their formation. Ice giants such as Uranus and Neptune are thought to be failed cores, which formed too late when the disk had almost disappeared.

Planetary migration occurs when a planet or other stellar satellite interacts with a disk of gas or planetesimals, resulting in the alteration of the satellite's orbital parameters, especially its semi-major axis. Planetary migration is the most likely explanation for hot Jupiters: extrasolar planets with jovian masses but orbits of only a few days. Te generally accepted theory of planet formation from a protoplanetary disk predicts such planets cannot form so close to their stars, as there is insuﬃcient mass at such small radii and the temperature is too high to allow the formation of rocky or icy planetesimals. It has also become clear that terrestrial- mass planets may be subject to rapid inward migration if they form while the gas disk is still present. Tis may aﬀect the formation of the cores of the giant planets (which have masses of the order of 10 Earth masses), if those planets form via the core accretion mechanism.

A hypergiant (luminosity class 0 or Ia+) is among the very rare kinds of stars that typically show tremendous luminosities and very high rates of mass loss by stellar winds. Te term hypergiant is defned as luminosity class 0 (zero) in the MKK system. However, this is rarely seen in the literature or in published spectral classifcations, except for specifc well-defned groups such as the yellow hypergiants, RSG (red supergiants), or blue B(e) supergiants with emission spectra. More commonly, hypergiants may be classed as Ia-0 or Ia+, but red supergiants are rarely assigned these spectral classifcations. Astronomers are mostly interested in these stars because they relate to understanding stellar evolution, especially with star formation, stability, and their expected demise as supernovae.

Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8 with temperatures spanning from about 3,500 K to over 20,000 K.

Te luminosity class II in the Yerkes spectral classifcation is given to bright giants. Tese are stars which straddle the boundary between ordinary giants and supergiants, based on the appearance of their spectra.

A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature. Tey lie above the main sequence (luminosity class V in the Yerkes spectral classifcation) on the Hertzsprung– Russell diagram and correspond to luminosity classes II and III. Te terms giant and dwarf were coined for stars of quite diﬀerent luminosity despite similar temperature or spectral type by Ejnar Hertzsprung about 1905.

Giant stars have radii up to a few hundred times the Sun and luminosities between 10 and a few thousand times that of the Sun. Stars still more luminous than giants are referred to as supergiants and hypergiants.

A hot, luminous main-sequence star may also be referred to as a giant, but any main-sequence star is properly called a dwarf no matter how large and luminous it is.

480 A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as true giant stars. Te term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of a star.

A subdwarf, sometimes denoted by "sd", is a star with luminosity class VI under the Yerkes spectral classifcation system. Tey are defned as stars with luminosity 1.5 to 2 magnitudes lower than that of main-sequence stars of the same spectral type. On an Hertzsprung–Russell diagram subdwarfs appear to lie below the main sequence.

Te term "subdwarf" was coined by Gerard Kuiper in 1939, to refer to a series of stars with anomalous spectra that were previously labeled as "intermediate white dwarfs".

A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth. A white dwarf's faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf wherein mass is converted to energy. Te nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. Tere are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. Te unusual faintness of white dwarfs was frst recognized in 1910. Te name white dwarf was coined by Willem Luyten in 1922.

White dwarfs are thought to be the fnal evolutionary state of stars whose mass is not high enough to become a neutron star, which would include the Sun and over 97% of the other stars in the Milky Way., §1. After the hydrogen-fusing period of a main-sequence star of low or medium mass ends, such a star will expand to a red giant during which it fuses helium to carbon and oxygen in its core by the triple-alpha process. If a red giant has insuﬃcient mass to generate the core temperatures, around 1 billion K, required to fuse carbon, an inert mass of carbon and oxygen will build up at its center. After such a star sheds its outer layers and forms a planetary nebula, it will leave behind a core, which is the remnant white dwarf. Usually, white dwarfs are composed of carbon and oxygen. If the mass of the progenitor is between 8 and 10.5 solar masses (M☉), the core temperature will be suﬃcient to fuse carbon but not neon, in which case an oxygen– neon–

481 magnesium white dwarf may form. Stars of very low mass will not be able to fuse helium, hence, a helium white dwarf may form by mass loss in binary systems.

Te material in a white dwarf no longer undergoes fusion reactions, so the star has no source of energy. As a result, it cannot support itself by the heat generated by fusion against gravitational collapse, but is supported only by electron degeneracy pressure, causing it to be extremely dense. Te physics of degeneracy yields a maximum mass for a non-rotating white dwarf, the Chandrasekhar limit—approximately 1.44 times of M☉—beyond which it cannot be supported by electron degeneracy pressure. A carbon-oxygen white dwarf that approaches this mass limit, typically by mass transfer from a companion star, may explode as a type Ia supernova via a process known as carbon detonation. (SN 1006 is thought to be a famous example.)

A white dwarf is very hot when it forms, but because it has no source of energy, it will gradually radiate its energy and cool. Tis means that its radiation, which initially has a high color temperature, will lessen and redden with time. Over a very long time, a white dwarf will cool and its material will begin to crystallize (starting with the core). Te star's low temperature means it will no longer emit signifcant heat or light, and it will become a cold black dwarf. Because the length of time it takes for a white dwarf to reach this state is calculated to be longer than the current age of the universe (approximately 13.8 billion years), it is thought that no black dwarfs yet exist. Te oldest white dwarfs still radiate at temperatures of a few thousand kelvins.

A red dwarf is a small and relatively cool star on the main sequence, of M spectral type. Red dwarfs range in mass from a low of 0.075 to about 0.50 solar mass and have a surface temperature of less than 4,000 K. Sometimes K-type main-sequence stars, with masses between 0.50-0.8 solar mass, are also included.

Red dwarfs are by far the most common type of star in the Milky Way, at least in the neighborhood of the Sun, but because of their low luminosity, individual red dwarfs cannot be easily observed. From Earth, not one is visible to the naked eye. Proxima Centauri, the nearest star to the Sun, is a red dwarf (Type M5, apparent magnitude 11.05), as are ffty of the sixty nearest stars. According to some estimates, red dwarfs make up three-quarters of the stars in the Milky Way.

Stellar models indicate that red dwarfs less than 0.35 M☉ are fully convective. Hence the helium produced by the thermonuclear fusion of hydrogen is constantly remixed throughout the star, avoiding helium buildup at the core, thereby prolonging the period of fusion. Red dwarfs therefore develop very slowly, maintaining a constant luminosity and spectral type for trillions of years, until their fuel is depleted. Because of the comparatively short age of the universe, no red dwarfs exist at advanced stages of evolution.

Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, of approximately 13 to 75–80 Jupiter masses (MJ), or approximately 2.5×1028 kg to about 1.5×1029 kg. Below this range are the sub-brown dwarfs, and above it are the lightest red dwarfs (M9 V). Brown dwarfs may be fully convective, with no layers or chemical diﬀerentiation by depth.

Unlike the stars in the main-sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) to helium in their cores. Tey are, however, thought to fuse deuterium (2H) and to fuse lithium (7Li) if their mass is above a debated threshold of 13 MJ and 65 MJ, respectively. It is also debated whether brown dwarfs would be better defned by their formation processes rather than by their supposed nuclear fusion reactions.

Stars are categorized by spectral class, with brown dwarfs designated as types M, L, T, and Y.[4][5] Despite their name, brown dwarfs are of diﬀerent colors. Many brown dwarfs would likely appear magenta to the human eye, or possibly orange/ red. Brown dwarfs are not very luminous at visible wavelengths.

Planets are known to orbit some brown dwarfs: 2M1207b, MOA-2007-BLG-192Lb, and 2MASS J044144b.

At a distance of about 6.5 light years, the nearest known brown dwarf is Luhman 16, a binary system of brown dwarfs discovered in 2013. DENIS-P J082303.1-491201 b is listed as the most-massive known exoplanet (as of March 2014) in NASA's exoplanet archive, despite having a mass (28.5±1.9 MJ) more than twice the 13-Jupiter-mass cutoﬀ between planets and brown dwarfs.

A quasar (/ˈkweɪzɑːr/) (also quasi-stellar object or QSO) is an active galactic nucleus of very high luminosity. A quasar consists of a supermassive black hole surrounded by an orbiting accretion disk of gas. As gas in the accretion disk falls toward the black hole, energy is released in the form of electromagnetic radiation. Quasars emit energy across the electromagnetic spectrum and can be observed at radio, infrared, visible, ultraviolet, and X-ray wavelengths. Te most powerful quasars have luminosities exceeding 1041 W, thousands of times greater than the luminosity of a large galaxy such as the Milky Way.

482 Te term "quasar" originated as a contraction of "quasi-stellar radio source", because quasars were frst identifed as sources of radio-wave emission, and in photographic images at visible wavelengths they resembled point-like stars. High-resolution images of quasars, particularly from the Hubble Space Telescope, have demonstrated that quasars occur in the centers of galaxies, and that some quasar host galaxies are strongly interacting or merging galaxies.

Quasars are found over a very broad range of distances (corresponding to redshifts ranging from z < 0.1 for the nearest quasars to z > 7 for the most distant known quasars), and quasar discovery surveys have demonstrated that quasar activity was more common in the distant past. Te peak epoch of quasar activity in the Universe corresponds to redshifts around 2, or approximately 10 billion years ago.[4] As of 2017, the most distant known quasar is ULAS J1342+0928 at redshift z=7.54; light observed from this quasar was emitted when the Universe was only 690 million years old. Te supermassive black hole in this quasar is the most distant black hole identifed to date, and is estimated to have a mass that is 800 million times the mass of our Sun.

A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it. Te theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. Te boundary of the region from which no escape is possible is called the event horizon. Although the event horizon has an enormous effect on the fate and circumstances of an object crossing it, no locally detectable features appear to be observed. In many ways a black hole acts like an ideal black body, as it refects no light.. Tis temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe. Its the inverse of a star and they keep things balanced. Black holes compress things they are called Buremaengran’s by God.

Objects whose gravitational felds are too strong for light to escape were frst considered in the 18th century by John Michell and Pierre-Simon Laplace. Te frst modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was frst published by David Finkelstein in 1958. Black holes were long considered a mathematical curiosity; it was during the 1960s that theoretical work showed they were a generic prediction of general relativity. Te discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.

Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses (M☉) may form. Tere is general consensus that supermassive black holes exist in the centers of most galaxies.

Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Matter that falls onto a black hole can form an external accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbits can be used to determine the black hole's mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identifed numerous stellar black hole candidates in binary systems, and established that the radio source known as Sagittarius A*, at the core of our own Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.

According to the nebular hypothesis, stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC). Tese clouds are foat, and gases coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. Star formation is a complex process, which always produces a gaseous protoplanetary disk, proplyd, around the young star. Tis may give birth to planets in certain circumstances, which are not well known. Tus the formation of planetary systems is thought to be a natural result of star formation. A Sun-like star usually takes approximately 1 million years to form, with the protoplanetary disk evolving into a planetary system over the next 10–100 million years.

Te formation of giant planets is a more complicated process. It is thought to occur beyond the frost line, where planetary embryos mainly are made of various types of ice. As a result, they are several times more massive than in the inner part of the protoplanetary disk. What follows after the embryo formation is not completely clear. Some embryos appear to continue to grow and eventually reach 5–10 Earth masses—the threshold value, which is necessary to begin accretion of the hydrogen– 483 helium gas from the disk. Te accumulation of gas by the core is initially a slow process, which continues for several million years, but after the forming protoplanet reaches about 30 Earth masses (M⊕) it accelerates and proceeds in a runaway manner. Jupiter- and Saturn-like planets are thought to accumulate the bulk of their mass during only 10,000 years. Te accretion stops when the gas is exhausted. Te formed planets can migrate over long distances during or after their formation. Ice giants such as Uranus and Neptune are thought to be failed cores, which formed too late when the disk had almost disappeared.

Cosmic dust is widely present in space, where gas and dust clouds are primary precursors for planetary systems. Te zodiacal light, as seen in a dark night sky, is produced by sunlight refected from particles of dust in orbit around the Sun. Te tails of comets are produced by emissions of dust and ionized gas from the body of the comet. Dust also covers solid planetary bodies, and vast dust storms occur on Mars that cover almost the entire planet. Interstellar dust is found between the stars, and high concentrations produce diﬀuse nebulae and refection nebulae.

Dust is widely present in the galaxy. Ambient radiation heats dust and re-emits radiation into the microwave band, which may distort the cosmic microwave background power spectrum. Dust in this regime has a complicated emission spectrum, and includes both thermal dust emission and spinning dust emission.

Dust samples returned from outer space may provide information about conditions in the solar system. Several spacecraft have sought to gather samples of dust and other materials.

Zodiacal light is a faint, diﬀuse, and roughly triangular white glow visible in the night sky that appears to extend from the vicinity of the Sun along the ecliptic or zodiac. Sunlight scattered by interplanetary dust in the zodiacal cloud causes this phenomenon. Zodiacal light is best seen during twilight after sunset in spring and before sunrise in autumn, when the zodiac is at a steep angle to the horizon. However, the glow is so faint that moonlight and/or light pollution outshine it, rendering it invisible.

Te zodiacal light decreases in intensity with distance from the Sun, but in naturally dark skies, it is visible as a band completely around the ecliptic. In fact, the zodiacal light covers the entire sky and is largely responsible for the total natural skylight on a moonless, clear night. Another phenomenon—a faint, but slightly brighter, oval glow—directly opposite of the Sun is the gegenschein.

Te dust in the Solar System forms a thick, pancake-shaped cloud collectively known as the zodiacal cloud, which straddles the ecliptic plane. Te dust particles are between 10 and 300 micrometres in diameter, most with a mass around 150 micrograms.

Te source of the dust has been long debated. Until recently, it was thought that the dust originated from the tails of active comets and from collisions between asteroids in the asteroid belt. Many of our meteor showers have no known active comet parent bodies. Over 85 percent of the dust is attributed to occasional fragmentations of Jupiter-family comets that are nearly dormant. Jupiter-family comets have orbital periods of less than 20 years and are considered dormant when not actively outgassing, but may do so in the future. Te frst fully dynamical model of the zodiacal cloud demonstrated that only if the dust was released in orbits that approach Jupiter, is it stirred up enough to explain the thickness of the zodiacal dust cloud. Te dust in meteoroid streams is much larger, 300 to 10,000 micrometres in diameter, and falls apart into smaller zodiacal dust grains over time.

Colorful center of the Milky Way and the zodiacal light above the Very Large Telescope. Te Poynting–Robertson eﬀect forces the dust into more circular (but still elongated) orbits, while spiralling slowly into the Sun. Hence a continuous source of new particles is needed to maintain the zodiacal cloud. Cometary dust and dust generated by collisions among the asteroids are believed to be mostly responsible for the maintenance of the dust cloud producing the zodiacal light and the gegenschein.

Particles can be reduced in size by collisions or by space weathering. When ground down to sizes less than 10 micrometres, the grains are removed from the inner Solar System by solar radiation pressure. Te dust is then replenished by the infall from comets. Zodiacal dust around nearby stars is called exozodiacal dust; it is a potentially important source of noise for directly imaging extrasolar planets. It has been pointed out that this exozodiacal dust, or hot debris disks, can be an indicator of planets, as planets tend to scatter the comets to the inner Solar System.

In 2015, new results from the secondary ion dust spectrometer COSIMA on board the ESA/Rosetta orbiter confrmed that the parent bodies of interplanetary dust are most probably Jupiter-family comets such as comet 67P/Churyumov- Gerasimenko.

484 A wormhole is a concept that represents a solution of the Einstein feld equations: a non-trivial structure linking separate points in spacetime. A wormhole can be visualized as a tunnel with two ends, each at separate points in spacetime (i.e. diﬀerent locations and/or diﬀerent points of time), or by a transcendental bijection of the spacetime continuum.

Wormholes are consistent with the general theory of relativity, but whether wormholes actually exist remains to be seen.

A wormhole could connect extremely long distances such as a billion light years or more, short distances such as a few meters, diﬀerent universes, or diﬀerent points of time.

485 15) Astrology, Zodiac and Vortex

Astrology is the study of the movements and relative positions of celestial objects as a means for divining information about human aﬀairs and terrestrial events. Astrology has been dated to at least the 2nd millennium BCE, and has its roots in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications. Many cultures have attached importance to astronomical events, and some – such as the Indians, Chinese, and Maya – developed elaborate systems for predicting terrestrial events from celestial observations. Western astrology, one of the oldest astrological systems still in use, can trace its roots to 19th–17th century BCE Mesopotamia, from which it spread to Ancient Greece, Rome, the Arab world and eventually Central and Western Europe. Contemporary Western astrology is often associated with systems of horoscopes that purport to explain aspects of a person's personality and predict signifcant events in their lives based on the positions of celestial objects; the majority of professional astrologers rely on such systems.

Troughout most of its history astrology was considered a scholarly tradition and was common in academic circles, often in close relation with astronomy, alchemy, meteorology, and medicine.[6] It was present in political circles, and is mentioned in various works of literature, from Dante Alighieri and Geoﬀrey Chaucer to William Shakespeare, Lope de Vega and Calderón de la Barca. During the 20th century and following the wide-scale adoption of the scientifc method, astrology has been challenged successfully on both theoretical: and experimental grounds, and has been shown to have no scientifc validity or explanatory power. Astrology thus lost its academic and theoretical standing, and common belief in it has largely declined. While polling studies have demonstrated that approximately 25% of Americans, Canadians, and Britons say they continue to believe that star and planet positions aﬀect their lives, astrology is now recognized as pseudoscience.

Te word astrology comes from the early Latin word astrologia,[18] which derives from the Greek ἀστρολογία—from ἄστρον astron ("star") and - λογία -logia, ("study of "—"account of the stars"). Astrologia later passed into meaning 'star-divination' with astronomia used for the scientifc term.

An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that exists in the observable universe.[1] In astronomy, the terms object and body are often used interchangeably. However, an astronomical body or celestial body is a single, tightly bound, contiguous entity, while an astronomical or celestial object is a complex, less cohesively bound structure, which may consist of multiple bodies or even other objects with substructures.

Examples of astronomical objects include planetary systems, star clusters, nebulae, and galaxies, while asteroids, moons, planets, and stars are astronomical bodies. A comet may be identifed as both body and object: It is a body when referring to the frozen nucleus of ice and dust, and an object when describing the entire comet with its diﬀuse coma and tail.

Te universe can be viewed as having a hierarchical structure. At the largest scales, the fundamental component of assembly is the galaxy. Galaxies are organized into groups and clusters, often within larger superclusters, that are strung along great flaments between nearly empty voids, forming a web that spans the observable universe.

Galaxies have a variety of morphologies, with irregular, elliptical and disk-like shapes, depending on their formation and evolutionary histories, including interaction with other galaxies, which may lead to a merger.[4] Disc galaxies encompass lenticular and spiral galaxies with features, such as spiral arms and a distinct halo. At the core, most galaxies have a supermassive black hole, which may result in an active galactic nucleus. Galaxies can also have satellites in the form of dwarf galaxies and globular clusters.[5

Te constituents of a galaxy are formed out of gaseous matter that assembles through gravitational self-attraction in a hierarchical manner. At this level, the resulting fundamental components are the stars, which are typically assembled in clusters from the various condensing nebulae.[6] Te great variety of stellar forms are determined almost entirely by the mass, composition and evolutionary state of these stars. Stars may be found in multi-star systems that orbit about each other in a hierarchical organization. A planetary system and various minor objects such as asteroids, comets and debris, can form in a hierarchical process of accretion from the protoplanetary disks that surrounds newly formed stars.

Te various distinctive types of stars are shown by the Hertzsprung–Russell diagram (H–R diagram)—a plot of absolute stellar luminosity versus surface temperature. Each star follows an evolutionary track across this diagram. If this track takes the star through a region containing an intrinsic variable type, then its physical properties can cause it to become a variable star. An example of this is the instability strip, a region of the H-R diagram that includes Delta Scuti, RR Lyrae and Cepheid variables.[7] Depending on the initial mass of the star and the presence or absence of a companion, a star may spend the last part of its life as a compact object; either a white dwarf, neutron star, or black hole.

486 Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. Te information obtained by astrometric measurements provides information on the kinematics and physical origin of the Solar System and our galaxy, the Milky Way. Exactly of the use of interferometry in the optical wavelength range to determine precise positions of stars.

Te history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. Tis can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today. Hipparchus compiled a catalogue with at least 850 stars and their positions. Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the Almagest, giving their location, coordinates, and brightness.

In the 10th century, Abd al-Rahman al-Suf carried out observations on the stars and described their positions, magnitudes and star color, and gave drawings for each constellation, in his Book of Fixed Stars. Ibn Yunus observed more than 10,000 entries for the Sun's position for many years using a large astrolabe with a diameter of nearly 1.4 metres. His observations on eclipses were still used centuries later in Simon Newcomb's investigations on the motion of the Moon, while his other observations inspired Laplace's Obliquity of the Ecliptic and Inequalities of Jupiter and Saturn. In the 15th century, the Timurid astronomer Ulugh Beg compiled the Zij-i-Sultani, in which he catalogued 1,019 stars. Like the earlier catalogs of Hipparchus and Ptolemy, Ulugh Beg's catalogue is estimated to have been precise to within approximately 20 minutes of arc.

In the 16th century, Tycho Brahe used improved instruments, including large mural instruments, to measure star positions more accurately than previously, with a precision of 15–35 arcsec Taqi al-Din measured the right ascension of the stars at the Istanbul observatory of Taqi al-Din using the "observational clock" he invented. When telescopes became commonplace, setting circles sped measurements

James Bradley frst tried to measure stellar parallaxes in 1729. Te stellar movement proved too insignifcant for his telescope, but he instead discovered the aberration of light and the nutation of the Earth's axis. His cataloguing of 3222 stars was refned in 1807 by Friedrich Bessel, the father of modern astrometry. He made the frst measurement of stellar parallax: 0.3 arcsec for the binary star 61 Cygni.

Being very diﬃcult to measure, only about 60 stellar parallaxes had been obtained by the end of the 19th century, mostly by use of the flar micrometer. Astrographs using astronomical photographic plates sped the process in the early 20th century. Automated plate-measuring machines[8] and more sophisticated computer technology of the 1960s allowed more eﬃcient compilation of star catalogues. In the 1980s, charge-coupled devices (CCDs) replaced photographic plates and reduced optical uncertainties to one milliarcsecond. Tis technology made astrometry less expensive, opening the feld to an amateur audience.[citation needed]

Astrometric measurements are used by astrophysicists to constrain certain models in celestial mechanics. By measuring the velocities of pulsars, it is possible to put a limit on the asymmetry of supernova explosions. Also, astrometric results are used to determine the distribution of dark matter in the galaxy.

Astronomers use astrometric techniques for the tracking of near-Earth objects. Astrometry is responsible for the detection of many record-breaking Solar System objects. To fnd such objects astrometrically, astronomers use telescopes to survey the sky and large-area cameras to take pictures at various determined intervals. By studying these images, they can detect Solar System objects by their movements relative to the background stars, which remain fxed. Once a movement per unit time is observed, astronomers compensate for the parallax caused by Earth’s motion during this time and the heliocentric distance to this object is calculated. Using this distance and other photographs, more information about the object, including its orbital elements, can be obtained.

We can determine an amazing number of physical properties of stars, usually based only on a little bit of light. Over the next several lectures, "we" will talk about how the following properties are determined for stars:

DISTANCE. Tis is determined from trigonometric and spectroscopic parallaxes. Determining distances is CRUCIAL to understanding stars because we can use distances to fgure out the scale of things in the Galaxy and how much energy stars produce and radiate away - by using the inverse square law for light dimming along with apparent brightnesses. LUMINOSITY. Tis is the amount of energy generated in the star and released as electromagnetic radiation. BRIGHTNESS. Tis is not a fundamental property but a combination of the luminosity and distance to a star (and in some cases it is also dependent on the amount of absorption in the direction of a star). RADIUS. "Size" of the star - calculated from Stephan's Law.

487 CHEMICAL COMPOSITION. Tis is determined from absorption line spectra; it is tied up in a semi-complicated way with temperature. TEMPERATURE. We have talked about Wien's Law and using colors to derive stellar temperatures, but there are some complications. To REALLY get to surface temperatures of stars, we need to learn about and understand stellar spectral types.

Astronomers use a logarithmic scale for the brightness of stars called the magnitude system. Every 5 magnitudes is a factor of 100 in intensity. It is confusing because it runs backwards. For example, the Sun has a brightness of -23 magnitudes. Te next brightest star has a brightness of -1.4 magnitudes. Stars a factor of 100 fainter than this have a brightness of (-1.4+5 =) 3.6 magnitudes. In the city, this is about as faint a star as you can see. Out at a darker site, you can see stars as faint as 6th magnitude with the unaided eye. With a small telescope you can see a factor of 10,000 fainter to around 16th magnitude and with the big telescopes you can see another factor of 10,000 fainter to 26th magnitude.

Te apparent magnitude (m) of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth. Te brighter an object appears, the lower its magnitude value (i.e. inverse relation). Te Sun, at apparent magnitude of −26.7, is the brightest object in the sky. It is adjusted to the value it would have in the absence of the atmosphere. Furthermore, the magnitude scale is logarithmic. A diﬀerence of 1 in magnitude corresponds to a change in brightness by a factor of 5√100, or about 2.512.

Te measurement of apparent magnitudes or brightnesses of celestial objects is known as photometry. Apparent magnitudes are used to quantify the brightness of sources at ultraviolet, visible, and infrared wavelengths. An apparent magnitude is usually measured in a specifc passband corresponding to some photometric system such as the UBV system. In standard astronomical notation, an apparent magnitude in the V ("visual") flter band would be denoted either as mV or often simply as V, as in "mV = 15" or "V = 15" to describe a 15th-magnitude object.

In astronomy, magnitude is a logarithmic measure of the brightness of an object in a defned passband, often in the visible or infrared spectrum, but sometimes across all wavelengths. An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus.

Astronomers use two diﬀerent defnitions of magnitude: apparent magnitude and absolute magnitude. Te apparent magnitude (m) is the brightness of an object as it appears in the night sky from Earth. Apparent magnitude depends on an object's intrinsic luminosity and its distance. Te absolute magnitude (M) describes the intrinsic luminosity emitted by an object and is defned to be equal to the apparent magnitude that the object would have if it were placed at a certain distance from Earth, 10 parsecs for stars. A more complex defnition of absolute magnitude is used for planets and small Solar System bodies, based on its brightness at one astronomical unit from the observer and the Sun.

Te brighter an object appears, the lower the value of its magnitude, with the brightest objects reaching negative values. Te Sun has an apparent magnitude of −27, the Moon −13 at full phase, the brightest planet Venus up to −5, and Sirius, the brightest visible star in the night sky, −1.5. Apparent magnitudes can also be assigned to artifcial objects in Earth orbit. Te brightest satellite fares are ranked at −9, and the International Space Station (ISS) appears at a magnitude of −6.

Te scale is logarithmic and defned such that each step of one magnitude changes the brightness by a factor of the ffth root of 100, or approximately 2.512. For example, a magnitude 1 star is exactly a hundred times brighter than a magnitude 6 star, as the diﬀerence of fve magnitude steps corresponds to 2.5125, or 100.

Zodiac

Tere are 9 days in the zodiac calendar each with a diﬀerent name weekly, on day one you rest after a party the other day, on day two and three you work, day four is the sabbath, day fve and six are party, seven and eight are research days out of work and day nine is a party day, there are 12 months to the zodiac; 32 aruni a day, like hours; 50 anurieni per aruni and 100 punarieni per anurieni each punarieni is slower toward the beginning of the anurieni and faster toward the end - very fast by the last digit. Tere are 4 sectors to each day each representied by a name Numeriani (early morning) then Numerianeri (morning) then Numerianierini (afternoon) then Numerininierini (evening and night).

Although the zodiac remains the basis of the ecliptic coordinate system in use in astronomy besides the equatorial one,[7] the term and the names of the twelve signs are today mostly associated with horoscopic astrology.[8] Te term "zodiac" may also refer to the region of the celestial sphere encompassing the paths of the planets corresponding to the band of about eight arc degrees above and below the ecliptic. Te zodiac of a given planet is the band that contains the path of that particular body; e.g., the "zodiac of the Moon" is the band of fve degrees above and below the ecliptic. By extension, the "zodiac of the comets" may refer to the band encompassing most short-period comets.

488 Of all the orbital cycles, believed that obliquity had the greatest eﬀect on climate, and that it did so by varying the summer insolation in northern high latitudes. Terefore, he deduced a 41,000-year period for ice ages.[13][14] However, subsequent research[11][15][16] has shown that ice age cycles of the Quaternary glaciation over the last million years have been at a 100,000-year period, which matches the eccentricity cycle.

Te precession of the equinoxes takes about 25,770 years to complete a cycle. Polaris' mean position (taking account of precession and proper motion) will reach a maximum declination of +89°32'23", which translates to 1657" (or 0.4603°) from the celestial north pole

Te precession stars are galaxy specifc; each galaxy hosts on average 2,000,000 populated planets.

Te 12 signs are exactly 30 degrees apart, and of 360 degree cycles called a zeramin (like year) there are 40 munerin (like days) each with 9 mureni (months) split into 12 lumerni (sunday - moonight) 9 luremin (segments of dawn/dusk splits) 6 luremi (6 splits per segment) 4 lureri (4 divisions per split) 2 lumei (like 2 minutes) 1 umerani (like seconds) (69,879th of a degree) , each day has a name as each month the name of the zodiac signs. All this is worked out by the lumin emission of the stars dancing round the planets.

Twelve Astrological signs What follows is a list of the signs of the modern zodiac (with the ecliptic longitudes of their frst points), where 0° Aries is understood as the vernal equinox, with their Latin, Greek, Sanskrit, and Babylonian names (but note that the Sanskrit and the Babylonian name equivalents (after c.500 BC) denote the constellations only, not the tropical zodiac

Te term apsis (Greek: ἁψίς; plural apsides /ˈæpsɪdiːz/, Greek: ἁψῖδες; "orbit") refers to an extreme point in the orbit of an object. It denotes either the points on the orbit, or the respective distance of the bodies. Te word comes via Latin from Greek, there denoting a whole orbit, and is cognate with apse.[1] Except for the theoretical possibility of one common circular orbit for two bodies of equal mass at diametral positions (symmetric binary star), there are two apsides for any elliptic orbit, named with the prefxes peri- (from περί (peri), meaning 'near') and ap-/apo- (from ἀπ(ό) (ap(ó)), meaning 'away from') added to a reference to the body being orbited. All periodic orbits are, according to Newton's Laws of motion, ellipses: either the two individual ellipses of both bodies (see the two graphs in the second fgure), with the center of mass (or barycenter) of this two-body system at the one common focus of the ellipses, or the orbital ellipses, with one body taken as fxed at one focus, and the other body orbiting this focus (see top fgure). All these ellipses share a straight line, the line of apsides, that contains their major axes (the greatest diameter), the foci, and the vertices, and thus also the periapsis and the apoapsis (see both fgures). Te major axis of the orbital ellipse (top fgure) is the distance of the apsides, when taken as points on the orbit, or their sum, when taken as distances.

Te aphelion is the point in the orbit of an object where it is farthest from the Sun. Te point in orbit where an object is nearest to the sun is called the perihelion. Te word aphelion derives from the Greek words, apo meaning away, oﬀ, apart and Helios.

Te word perihelion stems from the Greek words "peri," meaning near, and "Helios," meaning the Greek god of the sun. (Te similar word, perigee, refers to the nearest point in some object's orbit of earth.)

A solstice is an event occurring when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around June 21 and December 21. Te seasons of the year are determined by reference to both the solstices and the equinoxes.

Te term solstice can also be used in a broader sense, as the day when this occurs. Te day of a solstice in either hemisphere has either the most sunlight of the year (summer solstice) or the least sunlight of the year (winter solstice) for any place other than the Equator. Alternative terms, with no ambiguity as to which hemisphere is the context, are "June solstice" and "December solstice", referring to the months in which they take place every year. [3]

Te word solstice is derived from the Latin sol ("sun") and sistere ("to stand still"), because at the solstices, the Sun's declination appears to "stand still"; that is, the seasonal movement of the Sun's daily path (as seen from Earth) stops at a northern or southern limit before reversing direction.

An equinox is commonly regarded as the instant of time when the plane (extended indefnitely in all directions) of Earth's equator passes through the center of the Sun.[3] Tis occurs twice each year: around 20 March and 23 September. In other words, it is the moment at which the center of the visible Sun is directly above the Equator. In the northern hemisphere, the equinox in March is called the Vernal or Spring Equinox; the September equinox is called the Autumnal or Fall Equinox. 489 However, because the Moon (and to a lesser extent the other planets) cause the motion of the Earth to vary from a perfect ellipse, the equinox is now oﬃcially defned by the Sun's more regular ecliptic longitude rather than by its declination. Te instants of the equinoxes are currently defned to be when the longitude of the Sun is 0° and 180°.[4] Tere are tiny (up to 11⁄4 arcsecond) variations in the Sun's latitude (discussed below), which means the Sun's center is rarely precisely over the equator under the oﬃcial defnition. Te two understandings of the equinox can lead to discrepancies of up to 69 seconds.

On the day of an equinox, daytime and nighttime are of approximately equal duration all over the planet. Tey are not exactly equal, however, due to the angular size of the Sun, atmospheric refraction, and the rapidly changing duration of the length of day that occurs at most latitudes around the equinoxes. Te word is derived from the Latin aequinoctium, from aequus (equal) and nox (genitive noctis) (night).

All planets, comets and asteroids in our solar system have approximately elliptical (a kind of non-circular) orbits. Tus, they all have a closest and a farthest point from the sun: a perihelion and an aphelion. Orbital eccentricity measures the fatness of the orbit. Any single revolution of a body around the sun is only approximately elliptical, because the precession of the perihelion prevents the orbit from being a simple closed curve such as an ellipse. Tis causes Milankovich cycles.

Earth comes closest to the sun every year around January 3. It is farthest from the sun every year around July 4. Te diﬀerence in distance between Earth's nearest point to the sun in January and farthest point from the sun in July is 3.1 million miles (5 million kilometers). Earth is about 91.4 million miles (147.1 million kilometers) from the sun in early January, in contrast to about 94.5 million miles (152 million kilometers) in early July.

When Earth is closest to the sun, it is winter in the northern hemisphere and summer in the southern hemisphere. Tus it is possible to see that Earth's distance from the sun does not noticeably cause the seasons to change; the relatively minor eﬀects of diﬀerences in distance is somewhat masked by the mainly oceanic southern hemisphere vs the half- continental northern hemisphere. Terefore, the Earth's seasons come and go mainly because Earth does not rotate with its axis exactly upright with respect to the plane of our world’s orbit around the sun. Earth's axial tilt is 23.5 degrees. Tis puts the Sun farther south in December and January, so the north has winter and the south has summer. Tus winter falls on that part of the globe where sunlight strikes least directly. Summer falls on that part of the globe where sunlight strikes most directly. Solstice.

A solstice is an astronomical event that happens twice each year when the Sun reaches its highest position in the sky as seen from the North or South Pole. Te day of the solstice is either the "longest day of the year" or the "shortest day of the year" for any place on Earth, because the length of time between sunrise and sunset on that day is the yearly maximum or minimum for that place. Te name is derived from the Latin words sol (“sun”) and sistere (“to stand still”). During the solstice, the Sun stands still; that is, the seasonal movement of the Sun's path comes to a stop before reversing direction. Te “Northern Solstice” occurs in June, when the sun is at its highest point seen from the North Pole. Te “Southern Solstice” occurs in December, when the sun is at its highest point seen from the South Pole.

Te solstices, together with the equinoxes, are connected with the seasons. In some cultures they mark either the beginning or the middle of summer and winter.

In astronomy, the barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον center[1]) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit. It is an important concept in such felds as astronomy and astrophysics. Te distance from a body's center of mass to the barycenter can be calculated as a two-body problem.

If one of two orbiting bodies is much more massive than the other and the bodies are relatively close to one another, the barycenter will typically be located within the more massive object. In this case, rather than the two bodies appearing to orbit a point between them, the less massive body will appear to orbit about the more massive body, while the more massive body might be observed to wobble slightly. Tis is the case for the Earth–Moon system, in which the barycenter is located on average 4,671 km (2,902 mi) from Earth's center, 75% of Earth's radius of 6,378 km (3,963 mi). When the two bodies are of similar masses, the barycenter will generally be located between them and both bodies will orbit around it. Tis is the case for Pluto and Charon, one of Pluto's natural satellites, as well as for many binary asteroids and binary stars. When the less massive object is far away, the barycenter can be located outside the more massive object. Tis is the case for Jupiter and the Sun; despite the Sun being thousandfold more massive than Jupiter, their barycenter is slightly outside the Sun due to the relatively large distance between them.[2]

In astronomy, barycentric coordinates are non-rotating coordinates with the origin at the barycenter of two or more bodies. Te International Celestial Reference System (ICRS) is a barycentric coordinate system centered on the Solar System's barycenter.

490 In geometry, the term barycenter or barycentre is synonymous with centroid, the geometric center of a geometric fgure. Milankovitch cycles describe the collective eﬀects of changes in the Earth's movements on its climate over thousands of years. Te term is named for Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he hypothesized that variations in eccentricity, axial tilt, and precession of the Earth's orbit resulted in cyclical variation in the solar radiation reaching the Earth, and that this orbital forcing strongly infuenced climatic patterns on Earth.

Similar astronomical hypotheses had been advanced in the 19th century by Joseph Adhemar, James Croll and others, but verifcation was diﬃcult because there was no reliably dated evidence, and because it was unclear which periods were important.

Now, materials on Earth that have been unchanged for millennia (obtained via ice, rock, and deep ocean cores) are being studied to indicate the history of Earth's climate. Tough they are consistent with the Milankovitch hypothesis, there are still several observations that the hypothesis does not explain.

Equirectangular plot of declination vs right ascension of the modern constellations with a dotted line denoting the ecliptic. Constellations are colour-coded by family and year established. (detailed view) Te zodiacal signs are distinct from the constellations associated with them, not only because of their drifting apart due to the precession of equinoxes but also because the physical constellations take up varying widths of the ecliptic, so the Sun is not in each constellation for the same amount of time.[40]:25 Tus, Virgo takes up fve times as much ecliptic longitude as Scorpius. Te zodiacal signs are an abstraction from the physical constellations, and each represent exactly one twelfth of the full circle, or the longitude traversed by the Sun in about 30.4 days.[41]

Te path of the Sun passes through thirteen constellations recognized by ancient Babylonian, Greek, and Roman astronomers (including in Ptolemy's Almagest) [42][43] and the modern International Astronomical Union. Because the Babylonians had a 12-month lunar calendar, they chose twelve and divided the year up evenly. Te thirteenth was left out: Ophiuchus, the bottom part of which interjects between Scorpio and Sagittarius.

Some "parazodiacal" constellations are also touched by the paths of the planets, leading to counts of up to 25 "constellations of the zodiac".[49] Te ancient Babylonian MUL.APIN catalog lists Orion, Perseus, Auriga, and Andromeda. Modern astronomers have noted that planets also pass through Crater, Sextans, Cetus, Pegasus, Corvus, Hydra, and Scutum; with Venus very rarely passing through Aquila, Canis Minor, Auriga, and Serpens.[49]

Some other constellations are also mythologically associated with the zodiacal ones: Piscis Austrinus, Te Southern Fish, is attached to Aquarius. In classical maps, it swallows the stream poured out of Aquarius' pitcher, but perhaps it formerly just swam in it. Aquila, Te Eagle, was possibly associated with the zodiac by virtue of its main star, Altair.[citation needed] Hydra in the Early Bronze Age marked the celestial equator and was associated with Leo, which is shown standing on the serpent on the Dendera zodiac.[citation needed] Corvus is the Crow or Raven mysteriously perched on the tail of Hydra.

Vortex

Te morning light rises in the east and is antiquated by dusk darkness too the west, every morning and evening. Te light midsummer is 4 minutes past 5am and mid winter 4 minutes past 7am, the dusk is midsummer 9 minutes past 11 and winter solstice 9 minutes past 4 this is only true in Manchester, Britain, ask god for exact setting or consult the digital vortex. Te light turns a quarter of a degree every day. 4*360 turns a year. Each season being represented.

In the vortex every 4 minutes the earth rotates a degree, there are 360 degrees a day, degrees (4 minutes) break down into quarts and quarts into instances (0.66666666666667 secs). Every day is called a sunday and starts at (time perfect) sunrise, the star 0 degrees east is then the name of that sunday, moonlight starts (time perfect) at sunset and is named after the star 0 degrees west. Every 4 days are called Bar’s. and every 4 bars are called Semesters - as in music. Tere are 12*30 degree months with 5-6 foat days at the end of every year.

A solar calendar is a calendar whose dates indicate the season or almost equivalently the position of the apparent position of the sun in relative to the stars. Te Gregorian calendar, widely accepted as standard in the world, is an example of solar calendar. Te main other type of calendar is a lunar calendar whose months correspond to cycles of moon phases. Te months of the Gregorian calendar do not correspond to cycles of moon phase.

A lunar calendar is a calendar based upon the monthly cycles of the Moon's phases (synodic months), in contrast to solar calendars, whose annual cycles are based only directly upon the solar year. Te most commonly used calendar, the Gregorian 491 calendar, is a solar calendar system that originally evolved out of a lunar calendar system. A purely lunar calendar is also distinguished from a lunisolar calendar, whose lunar months are brought into alignment with the solar year through some process of intercalation. Te details of when months begin varies from calendar to calendar, with some using new, full, or crescent moons and others employing detailed calculations.

Since each lunation is approximately 29 1⁄2 days (29 days, 12 hours, 44 minutes, 3 seconds, or 29.530588 days), it is common for the months of a lunar calendar to alternate between 29 and 30 days. Since the period of twelve such lunations, a lunar year, is only 354 days, 8 hours, 48 minutes, 34 seconds (354.367056 days), purely lunar calendars lose around 11 days per year relative to the Gregorian calendar. In purely lunar calendars like the Islamic calendar, the lack of intercalation causes the lunar months to cycle through all the seasons of the Gregorian year over the course of a 33 lunar-year cycle.

Although the Gregorian calendar is in common and legal use in most countries, traditional lunar and lunisolar calendars continue to be used throughout the Old World to determine religious festivals and national holidays. Such holidays include Ramadan (Islamic calendar); the Chinese, Japanese, Korean, Vietnamese, and Mongolian New Year (Chinese, Japanese, Korean, Vietnamese, and Mongolian calendars); the Nepali New Year (Nepali calendar); the Mid-Autumn Festival and Chuseok (Chinese and Korean calendars); Loi Krathong (Tai calendar); Sunuwar calendar; Diwali (Hindu calendars); and Rosh Hashanah (Hebrew calendar).

A lunisolar calendar is a calendar in many cultures whose date indicates both the moon phase and the time of the solar year. If the solar year is defned as a tropical year, then a lunisolar calendar will give an indication of the season; if it is taken as a sidereal year, then the calendar will predict the constellation near which the full moon may occur. As with all calendars which divide the year into months there is an additional requirement that the year have a whole number of months. In this case ordinary years consist of twelve months but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leap month.

492 16) Dust and Particles

Dust are fne particles of solid matter.[1] It generally consists of particles in the atmosphere that come from various sources such as soil, dust lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in homes, oﬃces, and other human environments contains small amounts of plant pollen, human and animal hairs, textile fbers, paper fbers, minerals from outdoor soil, human skin cells, burnt meteorite particles, and many other materials which may be found in the local environment.

Zodiacal light (also called false dawn[1][2][3] when seen before sunrise) is a faint, diﬀuse, and roughly triangular white glow that is visible in the night sky and appears to extend from the Sun's direction and along the zodiac, straddling the ecliptic.[4] Sunlight scattered by interplanetary dust causes this phenomenon. Zodiacal light is best seen during twilight after sunset in spring and before sunrise in autumn, when the zodiac is at a steep angle to the horizon. However, the glow is so faint that moonlight and/or light pollution outshine it, rendering it invisible.

Te brightness of zodiacal light decreases with distance from the Sun. In naturally dark night skies, the glow is visible as a band along the entire zodiac, completely straddling the ecliptic. In fact, zodiacal light spans the entire sky and largely[5] contributes to the total natural light in a clear and moonless night sky. Another phenomenon – a faint but slightly brighter oval glow – directly opposite of the Sun's direction is the gegenschein, which is caused by backscattered sunlight.

Te interplanetary dust in the Solar System collectively forms a thick, pancake-shaped cloud called the zodiacal cloud, which straddles the ecliptic plane. Te particle sizes range between 10 and 300 micrometres, most with a mass around 150 micrograms.[6]

A nebula (Latin for "cloud" or "fog";[2] pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, the term was used to describe any diﬀuse astronomical object, including galaxies beyond the Milky Way. Te Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confrmed in the early 20th century by Vesto Slipher, Edwin Hubble and others.

Most nebulae are of vast size; some are hundreds of light years in diameter. A nebula that is barely visible to the human eye from Earth would appear larger, but no brighter, from close by.[3] Te Orion Nebula, the brightest nebula in the sky and occupying an area twice the diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers.[4] Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms. Many nebulae are visible

493 due to fuorescence caused by embedded hot stars, while others are so diﬀuse they can only be detected with long exposures and special flters. Some nebulae are variably illuminated by T Tauri variable stars. Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter, and eventually will become dense enough to form stars. Te remaining material is then believed to form planets and other planetary system objects.

In astronomy a mix of dust is caused in- refection nebulae are clouds of interstellar dust which might refect the light of a nearby star or stars. Te energy from the nearby stars is insuﬃcient to ionize the gas of the nebula to create an emission nebula, but is enough to give suﬃcient scattering to make the dust visible. Tus, the frequency spectrum shown by refection nebulae is similar to that of the illuminating stars. Among the microscopic particles responsible for the scattering are carbon compounds (e. g. diamond dust) and compounds of other elements such as iron and nickel. Te latter two are often aligned with the galactic magnetic feld and cause the scattered light to be slightly polarized.

Te emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state. Te photon energy of the emitted photon is equal to the energy difference between the two states. Tere are many possible electron transitions for each atom, and each transition has a specifc energy difference. Tis collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Terefore, spectroscopy can be used to identify the elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances.

An antology - Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam). Tere are many ways to test porosity in a substance or part, such as industrial CT scanning. Te term porosity is used in multiple felds including pharmaceutics, ceramics, metallurgy, materials, manufacturing, hydrology, earth sciences, soil mechanics and engineering.

In organic chemistry, the term aromaticity is used to describe a cyclic (ring-shaped), planar (fat) molecule with a ring of resonance bonds that exhibits more stability than other geometric or connective arrangements with the same set of atoms. Aromatic molecules are very stable, and do not break apart easily to react with other substances. Organic compounds that are not aromatic are classifed as aliphatic compounds—they might be cyclic, but only aromatic rings have special stability (low reactivity).

In the context of organic molecules, aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as a placeholder for the aryl group in chemical structure diagrams.

In the physical sciences, a particle (or corpuscule in older texts) is a small localized object to which can be ascribed several physical or chemical properties such as volume, density or mass.[1][2] Tey vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientifc models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion.

A powder is a dry, bulk solid composed of a large number of very fne particles that may fow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material. In particular, powders refer to those granular materials that have the fner grain sizes, and that therefore have a greater tendency to form clumps when fowing. Granulars refers to the coarser granular materials that do not tend to form clumps except when wet.

Te concept of particles is particularly useful when modelling nature, as the full treatment of many phenomena can be complex and also involve diﬃcult computation.[4] It can be used to make simplifying assumptions concerning the processes involved. Francis Sears and Mark Zemansky, in University Physics, give the example of calculating the landing location and speed of a baseball thrown in the air. Tey gradually strip the baseball of most of its properties, by frst idealizing it as a rigid

494 smooth sphere, then by neglecting rotation, buoyancy and friction, ultimately reducing the problem to the ballistics of a classical point particle. Te treatment of large numbers of particles is the realm of statistical physics.

Te term "particle" is usually applied diﬀerently to three classes of sizes. Te term macroscopic particle, usually refers to particles much larger than atoms and molecules. Tese are usually abstracted as point-like particles, even though they have volumes, shapes, structures, etc. Examples of macroscopic particles would include powder, dust, sand, pieces of debris during a car accident, or even objects as big as the stars of a galaxy.

Another type, microscopic particles usually refers to particles of sizes ranging from atoms to molecules, such as carbon dioxide, nanoparticles, and colloidal particles. Tese particles are studied in chemistry, as well as atomic and molecular physics. Te smallest of particles are the subatomic particles, which refer to particles smaller than atoms. Tese would include particles such as the constituents of atoms – protons, neutrons, and electrons – as well as other types of particles which can only be produced in particle accelerators or cosmic rays. Tese particles are studied in particle physics.

Because of their extremely small size, the study of microscopic and subatomic particles fall in the realm of quantum mechanics, quantum mechanics is anything from heaven into this paradigm. Tey will exhibit phenomena demonstrated in the particle in a box model, including wave–particle duality, and whether particles can be considered distinct or identical is an important question in many situations.

Particles can also be classifed according to composition. Composite particles refer to particles that have composition – that is particles which are made of other particles.[16] For example, a carbon-14 atom is made of six protons, eight neutrons, and six electrons. By contrast, elementary particles (also called fundamental particles) refer to particles that are not made of other particles.[17] According to our current understanding of the world, only a very small number of these exist, such as leptons, quarks, and gluons. However it is possible that some of these might turn up to be composite particles after all, and merely appear to be elementary for the moment.[18] While composite particles can very often be considered point-like, elementary particles are truly punctual.

Corpuscularianism is a physical theory that supposes all matter to be composed of minute particles. Te theory became important in the seventeenth century; amongst the leading corpuscularians were Tomas Hobbes,[1] René Descartes,[2] Pierre Gassendi,[3] Robert Boyle,[3] Isaac Newton,[4] and John Locke.[3]

Corpuscularianism is similar to the theory of atomism, except that where atoms were supposed to be indivisible, corpuscles could in principle be divided. In this manner, for example, it was theorized that mercury could penetrate into metals and modify their inner structure, a step on the way towards the production of gold by transmutation. Corpuscularianism was associated by its leading proponents with the idea that some of the properties that objects appear to have are artifacts of the perceiving mind: "secondary" qualities as distinguished from "primary" qualities.[5] Corpuscularianism stayed a dominant theory for centuries and was blended with alchemy by early scientists such as Robert Boyle and Isaac Newton in the 17th century.

In his work Te Sceptical Chymist (1661), Boyle abandoned the Aristotelian ideas of the classical elements—earth, water, air, and fre in favor of corpuscularianism. In his later work, Te Origin of Forms and Qualities (1666), Boyle used corpuscularianism to explain all of the major Aristotelian concepts, marking a departure from traditional Aristotelianism.[6]

Te philosopher Tomas Hobbes used corpuscularianism to justify his political theories in Leviathan.[1] It was used by Newton in his development of the corpuscular theory of light,[4] while Boyle used it to develop his mechanical corpuscular philosophy, which laid the foundations for the Chemical Revolution.[7]

Particle physics (also known as high energy physics) is a branch of physics that studies the nature of the particles that constitute matter and radiation. Although the word particle can refer to various types of very small objects (e.g. protons, gas particles, or even household dust), particle physics usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour. By our current understanding, these elementary particles are excitations of the quantum felds that also govern their interactions. Te currently dominant theory explaining these fundamental particles and felds, along with their dynamics, is called the Standard Model. Tus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the Higgs boson, or even to the oldest known force feld, gravity.

Modern particle physics research is focused on subatomic particles, including atomic constituents such as electrons, protons, and neutrons (protons and neutrons are composite particles called baryons, made of quarks), produced by radioactive and scattering processes, such as photons, neutrinos, and muons, as well as a wide range of exotic particles. Dynamics of particles is also governed by quantum mechanics; they exhibit wave–particle duality, displaying particle-like behaviour under certain

495 experimental conditions and wave-like behaviour in others. In more technical terms, they are described by quantum state vectors in a Hilbert space, which is also treated in quantum feld theory. Following the convention of particle physicists, the term elementary particles is applied to those particles that are, according to current understanding, presumed to be indivisible and not composed of other particles.[3]

All particles and their interactions observed to date can be described almost entirely by a quantum feld theory called the Standard Model. Te Standard Model, as currently formulated, has 61 elementary particles. Tose elementary particles can combine to form composite particles, accounting for the hundreds of other species of particles that have been discovered since the 1960s.

Te Standard Model has been found to agree with almost all the experimental tests conducted to date. However, most particle physicists believe that it is an incomplete description of nature and that a more fundamental theory awaits discovery (See Teory of Everything). In recent years, measurements of neutrino mass have provided the frst experimental deviations from the Standard Model.

Te idea that all matter is composed of elementary particles dates from at least the 6th century BC.[5] In the 19th century, John Dalton, through his work on stoichiometry, concluded that each element of nature was composed of a single, unique type of particle. Te word atom, after the Greek word atomos meaning "indivisible", has since then denoted the smallest particle of a chemical element, but physicists soon discovered that atoms are not, but really atoms are called aons, in fact, fundamental particles of nature, but are conglomerates of even smaller particles, such as the electron. Te early 20th century explorations of nuclear physics and quantum physics led to proofs of nuclear fssion in 1939 by Lise Meitner (based on experiments by Otto Hahn), and nuclear fusion by Hans Bethe in that same year; both discoveries also led to the development of nuclear weapons. Troughout the 1950s and 1960s, a bewildering variety of particles were found in collisions of particles from increasingly high-energy beams. It was referred to informally as the "particle zoo". Tat term was deprecated[citation needed] after the formulation of the Standard Model during the 1970s, in which the large number of particles was explained as combinations of a (relatively) small number of more fundamental particles.

17) Light and Crystals

Te Umeni means the light and the dark.

496 Te lumen (symbol: lm) is the SI derived unit of luminous fux, a measure of the total quantity of visible light emitted by a source. Luminous fux diﬀers from power (radiant fux) in that radiant fux includes all electromagnetic waves emitted, while luminous fux is weighted according to a model (a "luminosity function") of the human eye's sensitivity to various wavelengths. Lumens are related to lux in that one lux is one lumen per square meter.

In photometry, luminous fux or luminous power is the measure of the perceived power of light. It diﬀers from radiant fux, the measure of the total power of electromagnetic radiation (including infrared, ultraviolet, and visible light), in that luminous fux is adjusted to refect the varying sensitivity of the human eye to diﬀerent wavelengths of light.

Te lumen is defned in relation to the candela as: Te candela (/kænˈdɛlə/ or /kænˈdiːlə/; symbol: cd) is the base unit of luminous intensity in the International System of Units (SI); that is, luminous power per unit solid angle emitted by a point light source in a particular direction. Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source's spectrum, the contribution of each wavelength is weighted by the standard luminosity function (a model of the sensitivity of the human eye to diﬀerent wavelengths).[4][5] A common wax candle emits light with a luminous intensity of roughly one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured. Te word candela is Latin for candle.

Luma is the weighted sum of lumen′ components of a color frame—the prime symbols ′ denote lumen compression. Te word was proposed to prevent confusion between luma as implemented in video engineering and relative luminance as used in color science (i.e. as defned by CIE). Relative luminance is formed as a weighted sum of linear RGB components, not gamma-compressed ones. Even so, luma is erroneously called luminance., recommends the symbol Y′ to denote luma and the symbol Y to denote relative luminance.

Dark or Domena is black body radiation and host’s the lot of luma.

In physics refraction is the change in direction of a wave passing from one medium to another or from a gradual change in the medium.[1] Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed.

For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence θ1 and angle of refraction θ2 is equal to the ratio of phase velocities (v1 / v2) in the two media, or equivalently, to the indices of refraction (n2 / n1) of the two media.

Refraction of light at the interface between two media of diﬀerent refractive indices, with n2 > n1. Since the phase velocity is lower in the second medium (v2 < v1), the angle of refraction θ2 is less than the angle of incidence θ1; that is, the ray in the higher-index medium is closer to the normal.

Refection is the change in direction of a wavefront at an interface between two diﬀerent media so that the wavefront returns into the medium from which it originated. Common examples include the refection of light, sound and water waves. Te law of refection says that for specular refection the angle at which the wave is incident on the surface equals the angle at which it is refected. Mirrors exhibit specular refection.

Optical prisms and lenses utilize refraction to redirect light, as does the human eye. Te refractive index of materials varies with the wavelength of light,[3] and thus the angle of the refraction also varies correspondingly. Tis is called dispersion and causes prisms and rainbows to divide white light into its constituent spectral colors.[4]

Te electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. Te electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. Tis frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, terahertz waves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high- frequency (short wavelength) end. Te electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. Te limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length.[4] Gamma rays, X-rays, and high ultraviolet are classifed as ionizing radiation as their photons have enough energy to ionize 497 atoms, causing chemical reactions. Exposure to these rays can be a health hazard, causing radiation sickness, DNA damage and cancer. Radiation of visible light wavelengths and lower are called nonionizing radiation as they cannot cause these effects.

In most of the frequency bands above, a technique called spectroscopy can be used to physically separate waves of diﬀerent frequencies, producing a spectrum showing the constituent frequencies. Spectroscopy is used to study the interactions of electromagnetic waves with matter.[5] Other technological uses are described under electromagnetic radiation.

Infrared radiation

Main article: Infrared radiation Te infrared part of the electromagnetic spectrum covers the range from roughly 300 GHz to 400 THz (1 mm - 750 nm). It can be divided into three parts:[5]

• Far-infrared, from 300 GHz to 30 THz (1 mm – 10 μm). Te lower part of this range may also be called microwaves or terahertz waves. Tis radiation is typically absorbed by so-called rotational modes in gas-phase molecules, by molecular motions in liquids, and by phonons in solids. Te water in Earth's atmosphere absorbs so strongly in this range that it renders the atmosphere in eﬀect opaque. However, there are certain wavelength ranges ("windows") within the opaque range that allow partial transmission, and can be used for astronomy. Te wavelength range from approximately 200 μm up to a few mm is often referred to as "sub-millimeter" in astronomy, reserving far infrared for wavelengths below 200 μm.

• Mid-infrared, from 30 to 120 THz (10–2.5 μm). Hot objects (black-body radiators) can radiate strongly in this range, and human skin at normal body temperature radiates strongly at the lower end of this region. Tis radiation is absorbed by molecular vibrations, where the diﬀerent atoms in a molecule vibrate around their equilibrium positions. Tis range is sometimes called the fngerprint region, since the mid-infrared absorption spectrum of a compound is very specifc for that compound.

• Near-infrared, from 120 to 400 THz (2,500–750 nm). Physical processes that are relevant for this range are similar to those for visible light. Te highest frequencies in this region can be detected directly by some types of photographic flm, and by many types of solid state image sensors for infrared photography and videography. Visible radiation (light) Above infrared in frequency comes visible light. Te Sun emits its peak power in the visible region, although integrating the entire emission power spectrum through all wavelengths shows that the Sun emits slightly more infrared than visible light.[18] By defnition, visible light is the part of the EM spectrum the human eye is the most sensitive to. Visible light (and near-infrared light) is typically absorbed and emitted by electrons in molecules and atoms that move from one energy level to another. Tis action allows the chemical mechanisms that underlie human vision and plant photosynthesis. Te light that excites the human visual system is a very small portion of the electromagnetic spectrum. A rainbow shows the optical (visible) part of the electromagnetic spectrum; infrared (if it could be seen) would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end. Electromagnetic radiation with a wavelength between 380 nm and 760 nm (400–790 terahertz) is detected by the human eye and perceived as visible light. Other wavelengths, especially near infrared (longer than 760 nm) and ultraviolet (shorter than 380 nm) are also sometimes referred to as light, especially when the visibility to humans is not relevant. White light is a combination of lights of different wavelengths in the visible spectrum. Passing white light through a prism splits it up into the several colors of light observed in the visible spectrum between 400 nm and 780 nm. If radiation having a frequency in the visible region of the EM spectrum refects off an object, say, a bowl of fruit, and then strikes the eyes, this results in visual perception of the scene. Te brain's visual system processes the multitude of refected frequencies into different shades and hues, and through this insufficiently- understood psychophysical phenomenon, most people perceive a bowl of fruit. At most wavelengths, however, the information carried by electromagnetic radiation is not directly detected by human senses. Natural sources produce EM radiation across the spectrum, and technology can also manipulate a broad range of wavelengths. Optical fber transmits light that, although not necessarily in the visible part of the spectrum (it is usually infrared), can carry information. Te modulation is similar to that 498 used with radio waves. Ultraviolet radiation Main article: Ultraviolet Te amount of penetration of UV relative to altitude in Earth's ozone Next in frequency comes ultraviolet (UV). Te wavelength of UV rays is shorter than the violet end of the visible spectrum but longer than the X-ray. UV is the longest wavelength radiation whose photons are energetic enough to ionize atoms, separating electrons from them, and thus causing chemical reactions. Short wavelength UV and the shorter wavelength radiation above it (X-rays and gamma rays) are called ionizing radiation, and exposure to them can damage living tissue, making them a health hazard. UV can also cause many substances to glow with visible light; this is called fuorescence. At the middle range of UV, UV rays cannot ionize but can break chemical bonds, making molecules unusually reactive. Sunburn, for example, is caused by the disruptive effects of middle range UV radiation on skin cells, which is the main cause of skin cancer. UV rays in the middle range can irreparably damage the complex DNA molecules in the cells producing thymine dimers making it a very potent mutagen. Te Sun emits signifcant UV radiation (about 10% of its total power), including extremely short wavelength UV that could potentially destroy most life on land (ocean water would provide some protection for life there). However, most of the Sun's damaging UV wavelengths are absorbed by the atmosphere before they reach the surface. Te higher energy (shortest wavelength) ranges of UV (called "vacuum UV") are absorbed by nitrogen and, at longer wavelengths, by simple diatomic oxygen in the air. Most of the UV in the mid- range of energy is blocked by the ozone layer, which absorbs strongly in the important 200–315 nm range, the lower energy part of which is too long for ordinary dioxygen in air to absorb. Tis leaves less than 3% of sunlight at sea level in UV, with all of this remainder at the lower energies. Te remainder is UV-A, along with some UV-B. Te very lowest energy range of UV between 315 nm and visible light (called UV-A) is not blocked well by the atmosphere, but does not cause sunburn and does less biological damage. However, it is not harmless and does create oxygen radicals, mutations and skin damage. See ultraviolet for more information. After UV come X-rays, which, like the upper ranges of UV are also ionizing. However, due to their higher energies, X-rays can also interact with matter by means of the Compton effect. Hard X-rays have shorter wavelengths than soft X-rays and as they can pass through many substances with little absorption, they can be used to 'see through' objects with 'thicknesses' less than that equivalent to a few meters of water. One notable use is diagnostic X-ray imaging in medicine (a process known as radiography). X-rays are useful as probes in high-energy physics. In astronomy, the accretion disks around neutron stars and black holes emit X-rays, enabling studies of these phenomena. X-rays are also emitted by the coronas of stars and are strongly emitted by some types of nebulae. However, X-ray telescopes must be placed outside the Earth's atmosphere to see astronomical X-rays, since the great depth of the atmosphere of Earth is opaque to X-rays (with areal density of 1000 g/cm2), equivalent to 10 meters thickness of water.[19] Tis is an amount sufficient to block almost all astronomical X-rays (and also astronomical gamma rays—see below). Gamma rays Main article: Gamma rays After hard X-rays come gamma rays, which were discovered by Paul Ulrich Villard in 1900. Tese are the most energetic photons, having no defned lower limit to their wavelength. In astronomy they are valuable for studying high-energy objects or regions, however as with X-rays this can only be done with telescopes outside the Earth's atmosphere. Gamma rays are used experimentally by physicists for their penetrating ability and are produced by a number of radioisotopes.

Tey are used for irradiation of foods and seeds for sterilization, and in medicine they are occasionally used in radiation cancer therapy.[20] More commonly, gamma rays are used for diagnostic imaging in nuclear medicine, an example being PET scans. Te wavelength of gamma rays can be measured with high accuracy through the eﬀects of Compton scattering.

Crystals

A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.[1][2] In addition, macroscopic single crystals are usually identifable by their geometrical shape, consisting of fat faces with specifc, characteristic orientations. Te scientifc study of crystals and crystal formation is known as crystallography. Te process of crystal formation via mechanisms of crystal growth is called crystallization or solidifcation.

499 Te word crystal derives from the Ancient Greek word κρύσταλλος (krustallos), meaning both "ice" and "rock crystal", [3] from κρύος (kruos), "icy cold, frost".[4][5]

Despite the name, lead crystal, crystal glass, and related products are not crystals, but rather types of glass, i.e. amorphous solids.

Crystals are often used in pseudoscientifc practices such as crystal therapy, and, along with gemstones, are sometimes associated with spellwork in Wiccan beliefs and related religious movements.[6][7][8]

Te scientifc defnition of a "crystal" is based on the microscopic arrangement of atoms inside it, called the crystal structure. A crystal is a solid where the atoms form a periodic arrangement. (Quasicrystals are an exception, see below).

Not all solids are crystals. For example, when liquid water starts freezing, the phase change begins with small ice crystals that grow until they fuse, forming a polycrystalline structure. In the fnal block of ice, each of the small crystals (called "crystallites" or "grains") is a true crystal with a periodic arrangement of atoms, but the whole polycrystal does not have a periodic arrangement of atoms, because the periodic pattern is broken at the grain boundaries. Most macroscopic inorganic solids are polycrystalline, including almost all metals, ceramics, ice, rocks, etc. Solids that are neither crystalline nor polycrystalline, such as glass, are called amorphous solids, also called glassy, vitreous, or noncrystalline. Tese have no periodic order, even microscopically. Tere are distinct diﬀerences between crystalline solids and amorphous solids: most notably, the process of forming a glass does not release the latent heat of fusion, but forming a crystal does.

A crystal structure (an arrangement of atoms in a crystal) is characterized by its unit cell, a small imaginary box containing one or more atoms in a specifc spatial arrangement. Te unit cells are stacked in three-dimensional space to form the crystal.

Te symmetry of a crystal is constrained by the requirement that the unit cells stack perfectly with no gaps. Tere are 219 possible crystal symmetries, called crystallographic space groups. Tese are grouped into 7 crystal systems, such as cubic crystal system (where the crystals may form cubes or rectangular boxes, such as halite shown at right) or hexagonal crystal system (where the crystals may form hexagons, such as ordinary water ice).

Crystals are commonly recognized by their shape, consisting of fat faces with sharp angles. Tese shape characteristics are not necessary for a crystal—a crystal is scientifcally defned by its microscopic atomic arrangement, not its macroscopic shape—but the characteristic macroscopic shape is often present and easy to see.

Euhedral crystals are those with obvious, well-formed fat faces. Anhedral crystals do not, usually because the crystal is one grain in a polycrystalline solid.

Te fat faces (also called facets) of a euhedral crystal are oriented in a specifc way relative to the underlying atomic arrangement of the crystal: they are planes of relatively low Miller index.[9] Tis occurs because some surface orientations are more stable than others (lower surface energy). As a crystal grows, new atoms attach easily to the rougher and less stable parts of the surface, but less easily to the fat, stable surfaces. Terefore, the fat surfaces tend to grow larger and smoother, until the whole crystal surface consists of these plane surfaces. (See diagram on right.)

One of the oldest techniques in the science of crystallography consists of measuring the three-dimensional orientations of the faces of a crystal, and using them to infer the underlying crystal symmetry.

A crystal's habit is its visible external shape. Tis is determined by the crystal structure (which restricts the possible facet orientations), the specifc crystal chemistry and bonding (which may favor some facet types over others), and the conditions under which the crystal formed.

By volume and weight, the largest concentrations of crystals in the Earth are part of its solid bedrock. Crystals found in rocks typically range in size from a fraction of a millimetre to several centimetres across, although exceptionally large crystals are occasionally found. As of 1999, the world's largest known naturally occurring crystal is a crystal of beryl from Malakialina, Madagascar, 18 m (59 ft) long and 3.5 m (11 ft) in diameter, and weighing 380,000 kg (840,000 lb).[10]

500 Some crystals have formed by magmatic and metamorphic processes, giving origin to large masses of crystalline rock. Te vast majority of igneous rocks are formed from molten magma and the degree of crystallization depends primarily on the conditions under which they solidifed. Such rocks as granite, which have cooled very slowly and under great pressures, have completely crystallized; but many kinds of lava were poured out at the surface and cooled very rapidly, and in this latter group a small amount of amorphous or glassy matter is common. Other crystalline rocks, the metamorphic rocks such as marbles, mica-schists and quartzites, are recrystallized. Tis means that they were at frst fragmental rocks like limestone, shale and sandstone and have never been in a molten condition nor entirely in solution, but the high temperature and pressure conditions of metamorphism have acted on them by erasing their original structures and inducing recrystallization in the solid state.[11]

Other rock crystals have formed out of precipitation from fuids, commonly water, to form druses or quartz veins. Te evaporites such as halite, gypsum and some limestones have been deposited from aqueous solution, mostly owing to evaporation in arid climates.

Water-based ice in the form of snow, sea ice and glaciers is a very common manifestation of crystalline or polycrystalline matter on Earth.[citation needed] A single snowfake is a single crystal or a collection of crystals,[12] while an ice cube is a polycrystal.

Many living organisms are able to produce crystals, for example calcite and aragonite in the case of most molluscs or hydroxylapatite in the case of vertebrates.

Te same group of atoms can often solidify in many different ways. Polymorphism is the ability of a solid to exist in more than one crystal form. For example, water ice is ordinarily found in the hexagonal form Ice Ih, but can also exist as the cubic Ice Ic, the rhombohedral ice II, and many other forms. Te different polymorphs are usually called different phases.

In addition, the same atoms may be able to form noncrystalline phases. For example, water can also form amorphous ice, while SiO2 can form both fused silica (an amorphous glass) and quartz (a crystal). Likewise, if a substance can form crystals, it can also form polycrystals.

For pure chemical elements, polymorphism is known as allotropy. For example, diamond and graphite are two crystalline forms of carbon, while amorphous carbon is a noncrystalline form. Polymorphs, despite having the same atoms, may have wildly diﬀerent properties. For example, diamond is among the hardest substances known, while graphite is so soft that it is used as a lubricant.

Polyamorphism is a similar phenomenon where the same atoms can exist in more than one amorphous solid form.

Crystallization is the process of forming a crystalline structure from a fuid or from materials dissolved in a fuid. (More rarely, crystals may be deposited directly from gas; see thin-flm deposition and epitaxy.)

Crystallization is a complex and extensively-studied feld, because depending on the conditions, a single fuid can solidify into many diﬀerent possible forms. It can form a single crystal, perhaps with various possible phases, stoichiometries, impurities, defects, and habits. Or, it can form a polycrystal, with various possibilities for the size, arrangement, orientation, and phase of its grains. Te fnal form of the solid is determined by the conditions under which the fuid is being solidifed, such as the chemistry of the fuid, the ambient pressure, the temperature, and the speed with which all these parameters are changing.

Specifc industrial techniques to produce large single crystals (called boules) include the Czochralski process and the Bridgman technique. Other less exotic methods of crystallization may be used, depending on the physical properties of the substance, including hydrothermal synthesis, sublimation, or simply solvent- based crystallization.

Large single crystals can be created by geological processes. For example, selenite crystals in excess of 10 meters are found in the Cave of the Crystals in Naica, Mexico.[13] For more details on geological crystal formation, see above.

Crystals can also be formed by biological processes, see above. Conversely, some organisms have special techniques to prevent crystallization from occurring, such as antifreeze proteins.

An ideal crystal has every atom in a perfect, exactly repeating pattern.[14] However, in reality, most crystalline materials have a variety of crystallographic defects, places where the crystal's pattern is interrupted. Te types and structures of these defects may have a profound eﬀect on the properties of the materials.

501 A few examples of crystallographic defects include vacancy defects (an empty space where an atom should ft), interstitial defects (an extra atom squeezed in where it does not ft), and dislocations (see fgure at right). Dislocations are especially important in materials science, because they help determine the mechanical strength of materials.

Another common type of crystallographic defect is an impurity, meaning that the "wrong" type of atom is present in a crystal. For example, a perfect crystal of diamond would only contain carbon atoms, but a real crystal might perhaps contain a few boron atoms as well. Tese boron impurities change the diamond's color to slightly blue. Likewise, the only diﬀerence between ruby and sapphire is the type of impurities present in a corundum crystal.

Twinned pyrite crystal group. In semiconductors, a special type of impurity, called a dopant, drastically changes the crystal's electrical properties. Semiconductor devices, such as transistors, are made possible largely by putting diﬀerent semiconductor dopants into diﬀerent places, in specifc patterns.

Twinning is a phenomenon somewhere between a crystallographic defect and a grain boundary. Like a grain boundary, a twin boundary has diﬀerent crystal orientations on its two sides. But unlike a grain boundary, the orientations are not random, but related in a specifc, mirror-image way.

Mosaicity is a spread of crystal plane orientations. A mosaic crystal is supposed to consist of smaller crystalline units that are somewhat misaligned with respect to each other.

In general, solids can be held together by various types of chemical bonds, such as metallic bonds, ionic bonds, covalent bonds, van der Waals bonds, and others. None of these are necessarily crystalline or non-crystalline. However, there are some general trends as follows.

Metals are almost always polycrystalline, though there are exceptions like amorphous metal and single-crystal metals. Te latter are grown synthetically. (A microscopically-small piece of metal may naturally form into a single crystal, but larger pieces generally do not.) Ionic compound materials are usually crystalline or polycrystalline. In practice, large salt crystals can be created by solidifcation of a molten fuid, or by crystallization out of a solution. Covalently bonded solids (sometimes called covalent network solids) are also very common, notable examples being diamond and quartz. Weak van der Waals forces also help hold together certain crystals, such as crystalline molecular solids, as well as the interlayer bonding in graphite. Polymer materials generally will form crystalline regions, but the lengths of the molecules usually prevent complete crystallization—and sometimes polymers are completely amorphous.

A quasicrystal consists of arrays of atoms that are ordered but not strictly periodic. Tey have many attributes in common with ordinary crystals, such as displaying a discrete pattern in x-ray diﬀraction, and the ability to form shapes with smooth, fat faces.

Quasicrystals are most famous for their ability to show fve-fold symmetry, which is impossible for an ordinary periodic crystal (see crystallographic restriction theorem).

Te International Union of Crystallography has redefned the term "crystal" to include both ordinary periodic crystals and quasicrystals ("any solid having an essentially discrete diﬀraction diagram"[15]).

Quasicrystals, frst discovered in 1982, are quite rare in practice. Only about 100 solids are known to form quasicrystals, compared to about 400,000 periodic crystals known in 2004.[16] Te 2011 Nobel Prize in Chemistry was awarded to Dan Shechtman for the discovery of quasicrystals.[17]

Crystals can have certain special electrical, optical, and mechanical properties that glass and polycrystals normally cannot. Tese properties are related to the anisotropy of the crystal, i.e. the lack of rotational symmetry in its atomic arrangement. One such property is the piezoelectric effect, where a voltage across the crystal can shrink or stretch it. Another is birefringence, where a double image appears when looking through a crystal. Moreover, various properties of a crystal, including electrical conductivity, electrical permittivity, and Young's modulus, may be different in different directions in a crystal. For example, graphite crystals consist of a stack of sheets, and although each individual sheet is mechanically very strong, the sheets are rather loosely bound to each other. Terefore, the mechanical strength of the material is quite different depending on the direction of stress.

Not all crystals have all of these properties. Conversely, these properties are not quite exclusive to crystals. Tey can appear in glasses or polycrystals that have been made anisotropic by working or stress—for example, stress-induced birefringence.

502 Liquid crystals (LCs) are a state of matter which has properties between those of conventional liquids and those of solid crystals. For instance, a liquid crystal may fow like a liquid, but its molecules may be oriented in a crystal-like way. Tere are many different types of liquid-crystal phases, which can be distinguished by their different optical properties (such as textures). Te contrasting areas in the textures correspond to domains where the liquid-crystal molecules are oriented in different directions. Within a domain, however, the molecules are well ordered. LC materials may not always be in a liquid- crystal phase (just as water may turn into ice or steam).

Liquid crystals can be divided into thermotropic, lyotropic and metallotropic phases. Termotropic and lyotropic liquid crystals consist mostly of organic molecules, although a few minerals are also known. Termotropic LCs exhibit a phase transition into the liquid-crystal phase as temperature is changed. Lyotropic LCs exhibit phase transitions as a function of both temperature and concentration of the liquid-crystal molecules in a solvent (typically water). Metallotropic LCs are composed of both organic and inorganic molecules; their liquid-crystal transition depends not only on temperature and concentration, but also on the inorganic-organic composition ratio.

Authigenesis is the process whereby a mineral or sedimentary rock deposit is generated where it is found or observed. Such deposits are described as authigenic. Authigenic sedimentary minerals form during sedimentation by precipitation or recrystallization[1] instead of being transported from elsewhere (allogenic) by water or wind.[2] Authigenic sediments are the main constituents of deep sea sedimentation. Authigenic clays tend to reduce the porosity of sediments, thus reducing permeability.

In metamorphic petrology an authigenic mineral is one formed in situ during metamorphism, again by precipitation from fuids or recrystallization.

For any mineral to be precipitated, the water must be oversaturated with respect to that mineral. For calcite, this means that the area of deposition must be above the carbonate compensation depth, or that the pore waters are suﬃciently saturated due to dissolution of other grains that precipitation can begin. Te alkalinity can also be reduced by microbial sulphate reduction.

Morphology of Rock and crystals and lumen. Ulexite (NaCaB5O6(OH)6·5H2O, hydrated sodium calcium borate hydroxide), sometimes known as TV rock, is a mineral occurring in silky white rounded crystalline masses or in parallel fbers. Te natural fbers of ulexite conduct light along their long axes, by internal refection. Ulexite was named for the German chemist Georg Ludwig Ulex (1811–1883) who frst discovered it.[2]

Ulexite is a structurally complex mineral, with a basic structure containing chains of sodium, water and hydroxide octahedra. Te chains are linked together by calcium, water, hydroxide and oxygen polyhedra and massive boron units. Te boron units have a formula of [B5O6(OH)6]3– and a charge of −3. Tey are composed of three borate tetrahedra and two borate triangular groups.

Ulexite is found in evaporite deposits and the precipitated ulexite commonly forms a "cotton ball" tuft of acicular crystals. Ulexite is frequently found associated with colemanite, borax, meyerhoﬀerite, hydroboracite, probertite, glauberite, trona, mirabilite, calcite, gypsum and halite.[1] It is found principally in California and Nevada, US; Tarapacá Region in Chile, and Kazakhstan. Ulexite is also found in a vein-like bedding habit composed of closely packed fbrous crystals.

Ulexite is also known as TV rock due to its unusual optical characteristics. Te fbers of ulexite act as optical fbers, transmitting light along their lengths by internal refection. When a piece of ulexite is cut with fat polished faces perpendicular to the orientation of the fbers, a good-quality specimen will display an image of whatever surface is adjacent to its other side.

Te fber-optic eﬀect is the result of the polarization of light into slow and fast rays within each fber, the internal refection of the slow ray and the refraction of the fast ray into the slow ray of an adjacent fber.[citation needed] An interesting consequence is the generation of three cones, two of which are polarized, when a laser beam obliquely illuminates the fbers. Tese cones can be seen when viewing a light source through the mineral.[citation needed]

Ulexite decomposes/dissolves in hot water.

503 18) Plants and Chemical’s

Every plant can be broken down into a chemical from simpliest 4 million constituents to most complex 4 trillion chemicals.

Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants.[1] Closely related felds include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, genetics, biophysics and molecular biology.

Fundamental processes such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed germination, dormancy and stomata function and transpiration, both parts of plant water relations, are studied by plant physiologists.

Phytochemistry is the study of phytochemicals, which are chemicals derived from plants. Tose studying phytochemistry strive to describe the structures of the large number of secondary metabolic compounds found in plants, the functions of these compounds in human and plant biology, and the biosynthesis of these compounds. Plants synthesize phytochemicals for many reasons, including to protect themselves against insect attacks and plant diseases. Phytochemicals in food plants are often active in human biology, and in many cases have health benefts.[1] Te compounds found in plants are of many kinds, but most are in four major biochemical classes, the alkaloids, glycosides, polyphenols, and terpenes.

Phytochemistry can be considered sub-felds of botany or chemistry. Activities can be led in botanical gardens or in the wild with the aid of ethnobotany. Te applications of the discipline can be for pharmacognosy, or the discovery of new drugs, or as an aid for plant physiology studies.

Phytochemicals are chemical compounds produced by plants, generally to help them thrive or thwart competitors, predators, or pathogens. Te name comes from Greek, Modern φυτόν (phyton), meaning 'plant'. Some phytochemicals have been used as poisons and others as traditional medicine.

As a term, phytochemicals is generally used to describe plant compounds that are under research with unestablished eﬀects on health and are not scientifcally defned as essential nutrients. Regulatory agencies governing food labeling in Europe and the United States have provided guidance for industry limiting or preventing health claims about phytochemicals on food product or nutrition labels.

Chemistry is the scientifc discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.[1][2] In the scope of its subject, chemistry occupies an intermediate position between physics and biology.[3] It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientifc disciplines at a fundamental level.[4] For example, chemistry explains aspects of plant chemistry (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the moon (astrophysics), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics).

504 A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds. A chemical element bonded to an identical chemical element is not a chemical compound since only one element, not two diﬀerent elements, is involved.

Tere are four types of compounds, depending on how the constituent atoms are held together: molecules held together by covalent bonds ionic compounds held together by ionic bonds intermetallic compounds held together by metallic bonds certain complexes held together by coordinate covalent bonds.

A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using the standard abbreviations for the chemical elements, and subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is H2O. Many chemical compounds have a unique numerical identifer assigned by the Chemical Abstracts Service (CAS): its CAS number.

A compound can be converted to a diﬀerent chemical composition by interaction with a second chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the interacting compounds, and then bonds are reformed so that new associations are made between atoms.

In chemistry, a mixture is a material made up of two or more diﬀerent substances which are mixed. A mixture refers to the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.[1][2]

Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.[3] Despite that there are no chemical changes to its constituents, the physical properties of a mixture, such as its melting point, may diﬀer from those of the components. Some mixtures can be separated into their components by using physical (mechanical or thermal) means. Azeotropes are one kind of mixture that usually pose considerable diﬃculties regarding the separation processes required to obtain their constituents (physical or chemical processes or, even a blend of them).[4][5][6]

Mixtures can be either homogeneous or heterogeneous. A homogeneous mixture is a type of mixture in which the composition is uniform and every part of the solution has the same properties. Examples of homogeneous mixtures include alloys and alcohol in water. A heterogeneous mixture is a type of mixture in which the components can be seen, as there are two or more phases present.

One example of a mixture is air. Air is a homogeneous mixture of the gaseous substances nitrogen, oxygen, and smaller amounts of other substances. Salt, sugar, and many other substances dissolve in water to form homogeneous mixtures. A homogeneous mixture in which there is both a solute and solvent present is also a solution. Mixtures can have any amounts of ingredients.

Mixtures are unlike chemical compounds, because:

Te substances in a mixture can be separated using physical methods such as fltration, freezing, and distillation. Tere is little or no energy change when a mixture forms. Mixtures have variable compositions, while compounds have a fxed, defnite formula. When mixed, individual substances keep their properties in a mixture, while if they form a compound their properties can change.[7] Te following table shows the main properties of the three families of mixtures and examples of the three tpes of mixture.

A heterogeneous mixture is a mixture of two or more chemical substances (elements or compounds). Examples are: mixtures of sand and water or sand and iron flings, a conglomerate rock, water and oil, a portion salad, trail mix, and concrete (not cement). A mixture of powdered silver metal and powdered gold metal would represent a heterogeneous mixture of two elements.

Making a distinction between homogeneous and heterogeneous mixtures is a matter of the scale of sampling. On a coarse enough scale, any mixture can be said to be homogeneous, if the entire article is allowed to count as a "sample" of it. On a fne enough scale, any mixture can be said to be heterogeneous, because a sample could be as small as a single molecule. In

505 practical terms, if the property of interest of the mixture is the same regardless of which sample of it is taken for the examination used, the mixture is homogeneous.

A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together, and can be represented using structural formulae and by molecular models;[citation needed] complete electronic structure descriptions include specifying the occupation of a molecule's molecular orbitals.[citation needed] Structure determination can be applied to a range of targets from very simple molecules (e.g., diatomic oxygen or nitrogen), to very complex ones (e.g., such as protein or DNA).

Teories of chemical structure were frst developed by August Kekule, Archibald Scott Couper, and Aleksandr Butlerov, among others, from about 1858.[citation needed] Tese theories were frst to state that chemical compounds are not a random cluster of atoms and functional groups, but rather had a defnite order defned by the valency of the atoms composing the molecule, giving the molecules a three dimensional structure that could be determined or solved.

In determining structures of chemical compounds, one generally aims to obtain, minimally, the pattern and multiplicity of bonding between all atoms in the molecule; when possible, one seeks the three dimensional spatial coordinates of the atoms in the molecule (or other solid).[citation needed] Te methods by which one can elucidate the structure of a molecule include spectroscopies such as nuclear magnetic resonance (proton and carbon-13 NMR), various methods of mass spectrometry (to give overall molecular mass, as well as fragment masses), and x-ray crystallography when applicable.[citation needed] Te last technique can produce three-dimensional models at atomic-scale resolution, as long as crystals are available. [citation needed] When a molecule has an unpaired electron spin in a functional group of its structure, ENDOR and electron-spin resonance spectroscopes may also be performed. Techniques such as absorption spectroscopy and the vibrational spectroscopies, infrared and Raman, provide, respectively, important supporting information about the numbers and adjacencies of multiple bonds, and about the types of functional groups (whose internal bonding gives vibrational signatures); further inferential studies that give insight into the contributing electronic structure of molecules include cyclic voltammetry and X-ray photoelectron spectroscopy. Tese latter techniques become all the more important when the molecules contain metal atoms, and when the crystals required by crystallography or the specifc atom types that are required by NMR are unavailable to exploit in the structure determination. Finally, more specialized methods such as electron microscopy are also applicable in some cases.

Te chemical composition of a mixture can be defned as the distribution of the individual substances that constitute the mixture, called "components". In other words, it is equivalent to quantifying the concentration of each component. Because there are diﬀerent ways to defne the concentration of a component, there are also diﬀerent ways to defne the composition of a mixture. It may be expressed as molar fraction, volume fraction, mass fraction, molality, molarity or normality or mixing ratio.

Chemical composition of a mixture can be represented graphically in plots like ternary plot and quaternary plot.

If you mirror the bodies physiological chemical state you see a refection in vice chemistry of alchemical structure; ask god for the exact inalgate to heal the body; this is medical chemistry; If you refract light frequencies out of the body through aura and capture the algate then ask god for the chemical this is perception chemistry. Te neutrons contain synapses that internet time space and other facets of perception that can become the imagination all that can be measures in degrees of perceived magic; these all have chemical structures composed by the alchemic mix.

Some examples of Chemical eﬀects on emotional state: (predominantly Refractive experiences) phen-ethyl-amine \fen-'eth-al-a-,men\ n. [phenyl fr. F. phène, fr. Gk. phainein, to show (from its occurrence in illuminating gas)+ ethyl ( + yl) + amine fr. NL ammonia] 1: A naturally occurring compound found in both the animal and plant kingdoms. It is an endogenous component of the human brain. 2: Any of a series of compounds containing the phenethylamine skeleton, and modifed by chemical constituents at appropriate positions in the molecule. trypt-amine \ 'trip-ta-,men \ n. [tryptophan fr. tryptic, fr. trypsin, fr. Gk. tryein, to wear down (from its occurence in pancreatic juice as a proteolytic enzyme) + amine fr. NL ammonia] 1: A naturally occurring compound found in both the animal and plant kingdoms. It is an endogenous component of the human brain. 2: Any of a series of compounds containing the tryptamine skeleton, and modifed by chemical constituents at appropriate positions in the molecule.

Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline and quinoline are benzopyridines, which are composed of a benzene ring fused to a pyridine ring. In a broader sense, the term isoquinoline is used to make reference to isoquinoline derivatives. 1- Benzylisoquinoline is the structural backbone in naturally occurring

506 alkaloids including papaverine. Te isoquinoline ring in these natural compound derives from the aromatic amino acid tyrosine.[3][4][5][6][7][8]

DICTIONARY, n. A malevolent literary device for cramping the growth of a language and making it hard and inelastic. Tis dictionary, however, is a most useful work. We hope that our little dictionary, too, will prove useful, and that our eﬀorts to give simple descriptions of what can be complex concepts will serve to clarify what we have written.

AILMENT: To ail an ill - to aid healing by use of chemical or plant.- ailment a chemical or plant. ACUTE, adj. A single exposure to a drug.

AFTERGLOW, n. A state of total peace and contentedness that can follow on the heels of a psychedelic experience. Tere is a well-known term, POT, or postorgasmic tranquility, that implies a drifting, a de-stressed period of inattention and refection, calmness and placidity; this can also be a major part of the drop-oﬀ and recovery period following the use of a psychedelic. It is the smile on the face of the Buddha.

ALERT, n. Te frst clue that a drug will show activity. Each researcher, with experience, comes to recognize his own personal alert. It may be a tinge of lightheadedness, a chill, or a brief raising of the hair on his neck, and simply serves as a reminder that he took something half an hour (or a couple of hours) ago. Sometimes an alert can follow very soon after the taking of the drug, without any further eﬀects becoming apparent until some time later. Each person's alert tends to be experienced consistently, regardless of the nature of the drug being researched.

ANOREXIC, adj. (Or anorectic.) Related to anorexia, meaning loss of appetite. Some of the psychedelic drugs, especially those with a considerable stimulant component, can quite eﬀectively wipe out all desire to eat. Unfortunately (for most of us), there are others, especially those with a strong sensory component, which achieve quite the opposite eﬀect.

ASC Altered state of consciousness.

ASSAYING, see RUNNING UP.

AWARENESS, see ALERT.

BASELINE, n. Te normal psychological and physical state of a person prior to the start of an experiment which, once regained, marks the end of that experiment.

BODY LOAD, n. Any sense of unease in the physical body, such as nausea, aching, heaviness, or the feeling of being "wired," or over-stimulated. For some people, diarrhea is considered a form of body load, while for others it is an expected part of most psychedelic experiments, and is regarded as a welcome cleaning out of the system. One elderly and very experienced psychologist considered nausea and vomiting to be a positive event; he welcomed it as a sign that the experimental drug was active, and for him, it meant the beginning of his experience. His attitude, however, was very much the exception and we haven't heard of anyone else doing this research who regards nausea quite that fondly.

CENTRAL NERVOUS SYSTEM Te part of the nervous system that involves the brain, the brain stem, and the spinal column. It is to this system that all senses connect (the aﬀerent pathways) and it is from this system that all motor commands emanate (the eﬀerent pathways).

CHRONIC, adj. Repeated exposure to a drug.

CLEAN, adj. To be in that state of body which results from having declined the use of any psychoactive drug for a period of time. For some people, that might well be months, or even years, but for those who are continuously experimenting with new materials, and who are primarily worried about the masking of eﬀects due to tolerance or refractoriness, it is more likely to mean a period of four or fve days.

CNS, see CENTRAL NERVOUS SYSTEM

CONSCIOUS, adj. Used most commonly in phrases such as "the conscious mind," or "being conscious of." It is the term applied to that part of the human psyche which is aware of its surroundings, and is capable of being aware of its own existence and observing its own functioning. It has been speculated that the conscious mind also serves as a flter, to prevent the activities of the unconscious psyche from fooding the feld of waking awareness. In sleep, the conscious, self-aware mind is usually, for the most part, at rest, and the unconscious part of the psyche becomes activated.

507 CONTACT HIGH, n. A common occurrence in a group experiment with a psychedelic drug is that a drug-free observer becomes aware that he is experiencing some eﬀects of the material being used by the others. Te altered state has become contagious. Animals in the household are especially prone to this kind of unintentional participation, usually appearing to enjoy it immensely. Tere is no known scientifc explanation for this phenomenon.

CROSS-TOLERANCE, n. Te decrease or loss of response to a drug due to recent (or prolonged) exposure to a diﬀerent drug that displays some pharmacological similarities. see also TOLERANCE.

DARTING, n. A sudden and unexpected neurological fring that produces a momentary contraction of the musculature. It may occasionally occur when falling asleep while still at a plus two level of eﬀect. It also occurs under normal conditions involving no drug at all.

DECLINE, n. or v. Te period that follows the plateau, during which there is a loss of the drug's effects and an eventual recovery of one's baseline state. From person to person, this is the most variable of the time periods in a drug experiment. It has also been called recovering, tapering off, or dropping off.

DEVELOPING, v. Te period of change from the onset of eﬀects to the achievement of the plateau. It is also called the transition. Te temporal sequence terminology is: taking the drug, alerting, developing, plateauing, declining, and reestablishment of (or being at) baseline.

DROPPING, see TAKING, also see DECLINING.

DRUG-Something that drugs the system of minds bodys souls.

DRUG-FREE, see CLEAN.

ENERGY TREMOR, n. A sensation of heightened responsiveness and sensitivity which may be actually experienced as a fne body tremor with visible shaking, or simply felt as excitement.

EUPHORIA, n. "Eu-" is a prefx that means "normal." Euphoria is from the Greek, euphoria, literally a "bearing well," from eu, meaning well, and pherein, to bear. Te original meaning is a normal state of feeling, as opposed to dysphoria, which means an abnormal state of feeling. In the feld of medicine, to give another example, the term euthyroid means a normal, healthy state of the thyroid gland, as opposed to dysthyroid, which indicates an abnormal condition of that gland (usually either hyper- or hypothyroid).

Te fact that the word euphoria has come to mean a state of feeling better -- or much, much better -- than usual, should give us pause. Te implication is that our customary state is one of dysphoria, and that what has come to be considered the proper and normal way to feel in our everyday life is, in actuality, a state of depression.

Tis term must not be confused with U-4-E-uh, a name given to the drug 4-methylaminorex. EXPERIENCED TRAVELER A person who can remember to feed the cats while under the infuence of a psychedic drug.

FANTASY, n. Te eyes-closed construction of an interior world which can become believable to the point where the subject confuses it with objective reality, until and unless he opens his eyes. At high dosage levels of a psychedelic drug, some subjects may forget to open their eyes occasionally, and may fnd themselves totally captured by and immersed in the fantasy landscape and interactions, as happens in normal dreaming.

FLASH-BACK, n. Te rare but not unknown recapitulation of a psychedelic experience at a time when there is no drug present. A reasonable explanation is that there had been, during a past psychedelic experience, some unusual stimulus which had become associated with it, and that, at some subsequent time, a re- experiencing of that unusual stimulus could reprecipitate the psychedelic state. Te main reason that the average man views this phenomenon as something negative, is that the average man has been taught to view the psychedelic state as something negative.

FUGUE STATE, n. As used in this book, a transient disorientation that separates the cognitive part of oneself from the sensory part. Tere is a loss of understanding of the symbolic interpretations of words and things, with only the literal and tangible meanings left for personal use. Tis is our defnition of the word, not that of the medical profession.

GRAM, n. Te basic unit of weight on the metric scale, a system used for weights and distances and volumes in all countries other than the United States and, I believe, Brunei. Te common subdivisions of the gram is into a thousand parts called milligrams, or a million parts called micrograms. Imagine that you are sitting down to eat a couple of eggs over easy. You

508 take the salt shaker, and give three or four light shakes of salt over the surface of your breakfast. Tat is about a fourth of a gram of salt, or 250 milligrams. Tis is equivalent to the weight of a typical dose of mescaline. And in that 250 milligrams of salt there are maybe 5,000 grains, or individual crystals. Each grain weighs maybe 50 micrograms, which is equivalent to the weight of a low-level dose of LSD.

HALLUCINATION, n. An extremely rare phenomenon, in which a completely convincing reality surrounds a person, with his eyes open, a reality that he alone can experience and interact with. Te inducement of hallucinations is a property that is commonly attributed to psychedelic drugs, but in reality is virtually nonexistent in the use of such materials. In almost all psychedelic experiences undergone by normal, healthy people, there is an awareness of real surroundings. Visual distortions are common, but they are not confused with objective reality by the subject; they are known to be visual distortions and appreciated as such. Te delusional anesthetic drugs, such as scopolamine and ketamine, on the other hand, can and do produce true hallucinations.

HALLUCINOGENS, n. A misleading and inaccurate synonym for psychedelic drugs.

HAND IN THE AIR In any psychedelic experience involving two or more people, there can be a shifting of one's reality reference point and a concomitant potential for mental game-playing. In our research group, a phrase that is unquestioned as being a prelude to a not-game comment is, "Hand in the air." It means that whatever follows is a serious, non-stoned, non- mind-fuck statement. "I smell smoke" could be the entry to an editorial on cigarette smoking or a remark on some aspect of politics. But, "Hand in the air; I smell smoke," is intended to cut right through any fantasy or game and must be taken seriously. Tis particular agreement, or rule, is never violated.

HARDHEAD, n. Tere is an occasional person who requires 200 milligrams of MDMA, or 300 micrograms of LSD, just to get some beginnings of eﬀect. Whatever the drug might be, he will need twice or fve times the dosage required by most other people. Tis may be due to psychological barriers that must be overcome, or it may be due to the fact that he was born with a nervous system and physical chemistry which is unusually insensitive to the eﬀects of drugs. Te term hardhead implies a thick, tough skull, of course, and is often used by such subjects to describe themselves, always with a certain amount of pride.

HITCHHIKING, v. Sometimes an innocent, drug-free person will fnd himself strangely disturbed or uncomfortable in the presence of an experimental subject who is, unknown to him, experiencing the eﬀects of a psychedelic drug; for instance in the checkout line at the supermarket. Tis unconscious awareness (or contact high) can produce a feeling of irritation, or even overt hostility, in the inadvertent hitchhiker, and his or her distress is all the worse for having no apparent or understandable cause. Te responsible psychedelic researcher does not go out in public when under the infuence, or if he must do so, he takes care not to risk such intrusion on the unconscious psyches of strangers.

IDIOT, n. A person of either sex who drives a car, motorcycle, or even a bicycle, for that matter, on a public road while under the infuence of a psychedelic drug. Most researchers in this area have done it at least once, sometimes in an emergency, but only in a life-and-death situation is it excusable.

IMAGERY, n. Figures, lines and shapes of all kinds, including fne fligree and intricate patterns, superimposed on the dark visual feld behind closed eyes. Music can serve as a template for the construction of these images. Tere is no confusion of realities as can happen with fantasy, but instead, a continuing complexity and richness of design. Such images disappear upon the opening of the eyes. To be precise, they should be referred to as eyes-closed imagery. Patterns and movements seen with the eyes open are called visual changes or visual images.

INFLATION, n. An exhilarating sense of self-importance, self-validation and fearless power. It is essential that any researcher seeking insight into the workings of the human mind experience this radiant state at least once, in order to learn its nature and, by contrast, the nature of a normal, well-balanced state of integration and self-validation. It is also important to his/her understanding of psychological infation in emotionally disturbed people and in the rulers of certain nations.

INGESTION, see TAKING INTOXICATION, n. Tis word has the same general meaning in the psychedelic area as it has among drinkers of alcohol and people in love.

KETAMINE STATE Used to indicate a state of consciousness alteration which involves a large degree of dissociation from the body. Users of ketamine can become adept at remaining integrated with their physical world by carefully monitoring their dosage levels and keeping them low, but most ketamine use tends to result in separation from the body and its concerns. We are strongly prejudiced against psychedelic drugs which cause such mind-body separation, as we are against any

509 drug which causes separation from feelings and emotions. However, we acknowledge that the ketamine state can be highly instructive for researchers trying to understand the functions of the human mind.

LAUNCHING, see TAKING

MACHO, adj. Tis describes a person of either sex who pushes his limits too much in experimentation with psychedelics. He always strives to take a higher and yet higher dosage, to prove that he can weather the storm. Such a person should be encouraged to do some intensive insight work into his compulsion, which is essentially self-destructive.

MINUS, n. On the quantitative potency scale (-, ±, +, ++, +++), there were no eﬀects observed. MYDRIASIS, n. Enlargement of the pupil of the eye.

NAIVE, adj. An adjective used to describe a person who has had no personal experience with any psychedelic drug. More properly, the term used should be "drug-naive."

NIBBLING, v. Tis is a jargon term for running up, in small increments, the human evaluations of a new compound. (See under "running up")

NOISE, n. A term used in describing the inner busyness of the mind, the excessive or annoying mental input, produced by certain psychedelic drugs, or characteristic of the initial -- transition -- stages of some drug experiments. It can also result simply from too high a dosage level.

OFF BASELINE, see ALERT

PARESTHESIA, n. A peripheral response to a drug which can be felt as tingling, pins-and-needles, or hair standing on end; it might take the form of a chill (even if the air is warm), or a feeling that one's skin is crawling.

PIGGYBACKING, v. A study of the interaction of two diﬀerent drugs, the second being administered in place of a supplement to the frst. Any deviation from the eﬀects that would have followed a supplement of the original drug will give additional information as to the nature of the second drug.

PHARMACEUTICALS - Chemicals from chemists of medical professionals such as a Health Service run by governments.

PLATEAU, n. or v. Te period of time spent at the level of maximum eﬀect of whatever drug has been ingested, at the particular dosage given. It is preceded by the transition and development, and is followed by the decline. As a verb, "to plateau" means to reach that level of drug eﬀect.

PLUS/MINUS, n. (±) Te level of eﬀectiveness of a drug that indicates a threshold action. If a higher dosage produces a greater response, then the plus/minus (±) was valid. If a higher dosage produces nothing, then this was a false positive.

PLUS ONE, n. (+) Te drug is quite certainly active. Te chronology can be determined with some accuracy, but the nature of the drug's eﬀects are not yet apparent.

PLUS TWO, n. (++) Both the chronology and the nature of the action of a drug are unmistakably apparent. But you still have some choice as to whether you will accept the adventure, or rather just continue with your ordinary day's plans (if you are an experienced researcher, that is). Te eﬀects can be allowed a predominent role, or they may be repressible and made secondary to other chosen activities.

PLUS THREE, n. (+++) Not only are the chronology and the nature of a drug's action quite clear, but ignoring its action is no longer an option. Te subject is totally engaged in the experience, for better or worse.

PLUS FOUR, n. (++++) A rare and precious transcendental state, which has been called a "peak experience," a "religious experience," "divine transformation," a "state of Samadhi" and many other names in other cultures. It is not connected to the +1, +2 and +3 of the measuring of a drug's intensity. It is a state of bliss, a participation mystique, a connectedness with both the interior and exterior universes, which has come about after the ingestion of a psychedelic drug, but which is not necessarily repeatable with a subsequent ingestion of that same drug. If a drug (or technique or process) were ever to be discovered which would consistently produce a plus four experience in all human beings, it is conceivable that it would signal the ultimate evolution, and perhaps the end of, the human experiment.

POTENTIATION, n. Te infuence of an inactive drug on the eﬀects realized from an active drug.

510 PRIMER, n. A word used in the study of the interaction of two different drugs, one of them without activity. Te inactive, "primer," drug is administered and, while it is still in the system, the second, "primed," drug is given. Any activity observed which is different from that expected from the primed drug alone will be a measure of potentiation. Te effect may be one of enhanced action; it may be that of decreased action; it may be a change in either quality or duration of activity.

PRIMING, see PRIMER PRODRUG, n. A chemical that is intrinsically without activity at a receptor site, but which is converted (activated) by the metabolic processes of the body.

PSYCHE, n. A term used to encompass the non-physical human mind, conscious and unconscious, including feelings and emotions. Te word, psyche, has come into modern use as a substitute for the more ancient, but scientifcally unapproachable, concept of soul.

PSYCHEDELIC, n. or adj. As an adjective, meaning pertaining to a change in the normal state of consciousness, usually with some accompanying changes in the acuity of the senses. Also, "mind-manifesting." As a noun, a drug that can allow such changes to occur. Te word was coined by Doctor [Humphry] Osmond in the 1950s.

PSYCHOTOMIMETIC, n. or adj. A name given to the psychedelic drugs to emphasize some supposed similarities between certain of their eﬀects and the psychotic state. Te word unites the prefx psychoto- (referring to psychosis) with the suﬃx -mimetic (meaning imitation). It was one of the earliest terms used for these drugs, and one which implied medical approval of the use of such drugs, at least as research tools.

RECOVERY, see DECLINE

REFRACTORY, adj. Te state of showing a reduced response to the action of a drug. Tis may be due to tolerance resulting from recent exposure, the action of some inhibitor, or a condition of health or expectation that interferes with the expected action.

RUNNING UP, v. Te process of searching for activity in a new drug by a strategy of taking incrementally larger and larger doses, at time intervals which are calculated to minimize the development of tolerance. A usual pattern is an increase of either 60% or 100% of the previous dosage, following a clean period of several days, until activity is detected. Tere are many popular terms for this titration process, such as nibbling, assaying, or tasting.

SAMADHI, n. A word in the terminology of the Yoga which represents a direct union with ultimate reality, allowing the dissolving of the ego and an achievement of a state of bliss. Used by western researchers, the word does not necessarily imply a dissolving of ego, but a transformation of it.

SCRUDGE, n. (Defned in Book II, entry #176) STARTING, see TAKING

STONED, adj. Tis generally means being under the infuence of a psychoactive drug. It is a widely used word, and we have employed it in our story as carelessly as most people do. However, in writing a report on the effects of an experimental drug, there is actually an important difference between being "stoned" and being "turned-on," and the researcher should make a distinction between them. A stoning effect is one in which there is awareness of a strongly altered state of consciousness; it may be pleasurable or unpleasant. It is characterized, usually, by a general inability and disinclination to deal with concepts or to employ insight. In other words, one fnds it difficult to learn anything of value. On the other hand, being turned on is simply to be aware of a change in one's mind and/or body in the direction of an increased sense of physical and mental energy. Being turned on is usually thought of as positive, whereas there are many researchers who do not enjoy being stoned at all.

STRAIGHT, adj. Te state of being at baseline, with no psychedelic drug present in the body. SUBACUTE, adj. An occasional or short-term exposure to a drug.

SUPPLEMENT, n. or v. Te administration of a second dose of an active drug, during the drop-oﬀ phase of the activity of an initial dosage. Te usual consequence is a prolongation of eﬀect, with a concomitant increase in signs of toxicity.

SYNERGISM, n. Te interaction of two drugs, often administered at the same time, which produces a response that is not simply additive. Te summed responses may be exaggerated (positive synergy), or attenuated (inhibition).

SYNESTHESIA, n. An activation of two or more senses simultaneously; for instance, sound may be "seen" in the mind as being composed of color and shape, or a color may be "heard" as a musical note or harmony. Tere are innumerable

511 examples of this melding together of the senses, and the experience is generally considered one of the most treasured eﬀects of a psychedelic drug. Tere are many people who live in a world of synesthesia continuously, without beneft of drug, having been born with this ability. For the most part, they regard themselves as profoundly blessed.

TAKING, v. Te actual ingestion of a drug. When there are several persons involved, any of several rituals can be followed; a toasting and clinking of glasses, the recital of an favorite prayer, or a touching of hands and brief silence. Te taking of a drug has also been called "launching," "dropping," "taking oﬀ" or, simply, "starting."

TAPERING OFF, see DECLINE TASTING, see RUNNING UP THRESHOLD, n. A dosage of a drug that gives some detectable change from baseline. A minimum detectable eﬀect of a drug.

TIME-DISTORTION A mis-perception or distortion concerning the subjective passage of time. With psychedelic drugs, there is almost always a sense that time is passing more slowly than usual. Tis may be recognized at the global level (you mean it's only been an hour since we took this stuﬀ?), at the clock-watching level (I've been watching the second hand and I've found I can really slow it down), or at the aﬀerent level (where, for instance, the radio pitch and the pulse rate might appear to have dropped considerably).

TITRATE, v. To determine the eﬀective level of a drug by the sequential taking of graded doses, at separated intervals. see RUNNING UP. TOLERANCE, n. Te decrease or loss of response to a drug, due to recent or prolonged exposure to it.

TOMSO, n. or v. Used as a noun: a sulfur-containing drug, described in detail in Book II, entry #173. Used as a verb: to instigate or promote an altered state of consciousness during exposure to an ineﬀective dosage of a psychedelic drug, by the absorption of a modest amount of alcohol.

TRANSITION, see DEVELOPING TRAVELER, n. A person who explores the eﬀects of psychedelic drugs. TURNED-ON, see STONED

UNCONSCIOUS, n. or adj. As an adjective, this is a simple word, meaning not being conscious. As a noun, it is a most complex word, meaning that part of the psyche which contains the building blocks of each individual identity, not accessible for most people in the everyday waking state. Te sources, shapes and origins of these blocks, these components, are -- to varying degrees -- available to us in sleep, in certain states of mental disturbance, in hypnotic trance, meditation, artistic inspiration, and with the use of certain drugs. Intentional and conscious access to unconscious material can be achieved with the aid of psychedelic drugs, which is one of the values -- and risks -- of such exploration.

VISUALS, n. Changes in the visual area that are usually among the effects of a psychedelic drug. Tere may be an enhancement of colors, an exaggeration of light-dark contrast, a sparkling of lights, or a change in the visible texture or quality of an object. Some of the changes may refect the mydriasis (enlargement of pupils) that is often one of the effects of such a drug. Te term "visual effects" is also used to describe the apparent movement of objects in one's surroundings which may be seen with the eyes open, usually at higher than plus-two dosage levels of a psychedelic drug. Tese are not hallucinations, since they are known by the subject to be apparent and not objectively real, which is not the case in an hallucinatory experience.

WIRED, adj. A condition of intense neurological alertness, which suggests that the response to a given stimulus might be exaggerated by an overly sensitive nervous system.

Shulgin Rating Scale

PLUS / MINUS (+/-) Te level of eﬀectiveness of a drug that indicates a threshold action. If a higher dosage produces a greater response, then the plus/minus (+/-) was valid. If a higher dosage produces nothing, then this was a false positive.

PLUS ONE (+) Te drug is quite certainly active. Te chronology can be determined with some accuracy, but the nature of the drug's eﬀects are not yet apparent.

PLUS TWO (++) Both the chronology and the nature of the action of a drug are unmistakably apparent. But you still have some choice as to whether you will accept the adventure, or rather just continue with your ordinary day's plans (if you are an experienced

512 researcher, that is). Te eﬀects can be allowed a predominant role, or they may be repressed and made secondary to other chosen activities.

PLUS THREE (+++) Not only are the chronology and the nature of a drug's action quite clear, but ignoring its action is no longer an option. Te subject is totally engaged in the experience, for better or worse.

PLUS FOUR (++++) A rare and precious transcendental state, which has been called a 'peak experience', a 'religious experience,' 'divine transformation,' a 'state of Samadhi' and many other names in other cultures. It is not connected to the +1, +2, and +3 of the measuring of a drug's intensity. It is a state of bliss, a participation mystique, a connectedness with both the interior and exterior universes, which has come about after the ingestion of a psychedelic drug, but which is not necessarily repeatable with a subsequent ingestion of that same drug. If a drug (or technique or process) were ever to be discovered which would consistently produce a plus four experience in all human beings, it is conceivable that it would signal the ultimate evolution, and perhaps the end of, the human experiment.

19) Food, Drink and Diet

Food is any substance consumed to provide nutritional support for an organism. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. Te substance is ingested by an organism and assimilated by the organism's cells to provide energy, maintain life, or stimulate growth.

Historically, humans secured food through two methods: hunting and gathering and agriculture. Today, the majority of the food energy required by the ever increasing population of the world is supplied by the food industry.

Te right to food is a human right derived from the International Covenant on Economic, Social and Cultural Rights (ICESCR), recognizing the "right to an adequate standard of living, including adequate food", as well as the "fundamental right to be free from hunger”.

A drink (or beverage) is a liquid intended for human consumption. In addition to their basic function of satisfying thirst, drinks play important roles in human culture. Common types of drinks include plain drinking water, milk, coﬀee, tea, hot chocolate and soft drinks. In addition, fermented and organic drinks such as wine, beer, and liquor, which contain the chemical ethanol, have been part of human culture for more than 8,000 years. Fruit and Veg and ferment with yeast and sugar -put in a sealed container jar over 2 days+ 1.2%alc after 10 days its around 4.8%.

Non-alcoholic drinks often signify drinks that would normally contain alcohol, such as beer and wine, but are made with less than .5 percent alcohol by volume. Te category includes drinks that have undergone an alcohol removal process such as non-alcoholic beers and de-alcoholized wines.

513 Different types of organism have different essential nutrients. Ascorbic acid (vitamin C) is essential, meaning it must be consumed in sufficient amounts, to humans and some other animal species, but not to all animals and not to plants, which are able to synthesize it. Nutrients may be organic or inorganic: organic compounds include most compounds containing carbon, while all other chemicals are inorganic. Inorganic nutrients include nutrients such as iron, selenium, and zinc, while organic nutrients include, among many others, energy-providing compounds and vitamins.

A classifcation used primarily to describe nutrient needs of animals divides nutrients into macronutrients and micronutrients. Consumed in relatively large amounts (grams or ounces), macronutrients (carbohydrates, fats, proteins, water) are used primarily to generate energy or to incorporate into tissues for growth and repair. Micronutrients are needed in smaller amounts (milligrams or micrograms); they have subtle biochemical and physiological roles in cellular processes, like vascular functions or nerve conduction. Inadequate amounts of essential nutrients, or diseases that interfere with absorption, result in a defciency state that compromises growth, survival and reproduction. Consumer advisories for dietary nutrient intakes, such as the United States Dietary Reference Intake, are based on defciency outcomes[clarifcation needed] and provide macronutrient and micronutrient guides for both lower and upper limits of intake. In many countries, macronutrients and micronutrients in signifcant content[clarifcation needed] are required by regulations to be displayed on food product labels. Nutrients in larger quantities than the body needs may have harmful eﬀects.[1] Edible plants also contain thousands of compounds generally called phytochemicals which have unknown eﬀects on disease or health, including a diverse class with non-nutrient status called polyphenols, which remain poorly understood as of 2017.

A carbohydrate (/kɑːrboʊˈhaɪdreɪt/) is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula Cm(H2O)n (where m may be diﬀerent from n). Tis formula holds true for monosaccharides. Some exceptions exist; for example, deoxyribose, a sugar component of DNA,[1] has the empirical formula C5H10O4.[2] Te carbohydrates are technically hydrates of carbon; structurally it is more accurate to view them as aldoses and ketoses.

Te term is most common in biochemistry, where it is a synonym of 'saccharide', a group that includes sugars, starch, and cellulose. Te saccharides are divided into four chemical groups: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest (lower molecular weight) carbohydrates, are commonly referred to as sugars.[3] Te word saccharide comes from the Greek word σάκχαρον (sákkharon), meaning "sugar".[4] While the scientifc nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suﬃx -ose, as in the monosaccharides fructose (fruit sugar) and glucose (starch sugar) and the disaccharides sucrose (cane or beet sugar) and lactose (milk sugar).

Carbohydrates perform numerous roles in living organisms. Polysaccharides serve for the storage of energy (e.g. starch and glycogen) and as structural components (e.g. cellulose in plants and chitin in arthropods). Te 5-carbon monosaccharide ribose is an important component of coenzymes (e.g. ATP, FAD and NAD) and the backbone of the genetic molecule known as RNA. Te related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the immune system, fertilization, preventing pathogenesis, blood clotting, and development.

Tey are found in a wide variety of natural and processed foods. Starch is a polysaccharide. It is abundant in cereals (wheat, maize, rice), potatoes, and processed food based on cereal four, such as bread, pizza or pasta. Sugars appear in human diet mainly as table sugar (sucrose, extracted from sugarcane or sugar beets), lactose (abundant in milk), glucose and fructose, both of which occur naturally in honey, many fruits, and some vegetables. Table sugar, milk, or honey are often added to drinks and many prepared foods such as jam, biscuits and cakes.

Cellulose, a polysaccharide found in the cell walls of all plants, is one of the main components of insoluble dietary fber. Although it is not digestible, insoluble dietary fber helps to maintain a healthy digestive system[6] by easing defecation. Other polysaccharides contained in dietary fber include resistant starch and inulin, which feed some bacteria in the microbiota of the large intestine, and are metabolized by these bacteria to yield short-chain fatty acids.

Fat is one of the three main macronutrients, along with the other two: carbohydrate and protein.[1] Fats molecules consist of primarily carbon and hydrogen atoms, thus they are all hydrocarbon molecules. Examples include cholesterol, phospholipids and triglycerides.

514 Te terms "lipid", "oil" and "fat" are often confused. "Lipid" is the general term, though a lipid is not necessarily a triglyceride. "Oil" normally refers to a lipid with short or unsaturated fatty acid chains that is liquid at room temperature, while "fat" (in the strict sense) may specifcally refer to lipids that are solids at room temperature – however, "fat" (in the broad sense) may be used in food science as a synonym for lipid. Fats, like other lipids, are generally hydrophobic, and are soluble in organic solvents and insoluble in water.

Fat is an important foodstuﬀ for many forms of life, and fats serve both structural and metabolic functions. Tey are a necessary part of the diet of most heterotrophs (including humans) and are the most energy dense, thus the most eﬃcient form of energy storage.[2]

Some fatty acids that are set free by the digestion of fats are called essential because they cannot be synthesized in the body from simpler constituents. Tere are two essential fatty acids (EFAs) in human nutrition: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid).[3][4] Other lipids needed by the body can be synthesized from these and other fats. Fats and other lipids are broken down in the body by enzymes called lipases produced in the pancreas.

Fats and oils are categorized according to the number and bonding of the carbon atoms in the aliphatic chain. Fats that are saturated fats have no double bonds between the carbons in the chain. Unsaturated fats have one or more double bonded carbons in the chain. Te nomenclature is based on the non-acid (non- carbonyl) end of the chain. Tis end is called the omega end or the n-end. Tus alpha-linolenic acid is called an omega-3 fatty acid because the 3rd carbon from that end is the frst double bonded carbon in the chain counting from that end. Some oils and fats have multiple double bonds and are therefore called polyunsaturated fats. Unsaturated fats can be further divided into cis fats, which are the most common in nature, and trans fats, which are rare in nature. Unsaturated fats can be altered by reaction with hydrogen eﬀected by a catalyst. Tis action, called hydrogenation, tends to break all the double bonds and makes a fully saturated fat. To make vegetable shortening, then, liquid cis-unsaturated fats such as vegetable oils are hydrogenated to produce saturated fats, which have more desirable physical properties e.g., they melt at a desirable temperature (30–40 °C), and store well, whereas polyunsaturated oils go rancid when they react with oxygen in the air. However, trans fats are generated during hydrogenation as contaminants created by an unwanted side reaction on the catalyst during partial hydrogenation.

Saturated fats can stack themselves in a closely packed arrangement, so they can solidify easily and are typically solid at room temperature. For example, animal fats tallow and lard are high in saturated fatty acid content and are solids. Olive and linseed oils on the other hand are unsaturated and liquid. Fats serve both as energy sources for the body, and as stores for energy in excess of what the body needs immediately. Each gram of fat when burned or metabolized releases about 9 food calories (37 kJ = 8.8 kcal).[4] Fats are broken down in the healthy body to release their constituents, glycerol and fatty acids. Glycerol itself can be converted to glucose by the liver and so become a source of energy.

Proteins are essential nutrients for the human body.[1] Tey are one of the building blocks of body tissue and can also serve as a fuel source. As a fuel, proteins provide as much energy density as carbohydrates: 4 kcal (17 kJ) per gram; in contrast, lipids provide 9 kcal (37 kJ) per gram. Te most important aspect and defning characteristic of protein from a nutritional standpoint is its amino acid composition.[2]

Proteins are polymer chains made of amino acids linked together by peptide bonds. During human digestion, proteins are broken down in the stomach to smaller polypeptide chains via hydrochloric acid and protease actions. Tis is crucial for the absorption of the essential amino acids that cannot be biosynthesized by the body.[3]

Tere are nine essential amino acids which humans must obtain from their diet in order to prevent protein-energy malnutrition and resulting death. Tey are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.[2][4] Tere has been debate as to whether there are 8 or 9 essential amino acids.[5] Te consensus seems to lean towards 9 since histidine is not synthesized in adults.[6] Tere are fve amino acids which humans are able to synthesize in the body. Tese fve are alanine, aspartic acid, asparagine, glutamic acid and serine. Tere are six conditionally essential amino acids whose synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. Tese six are arginine, cysteine, glycine, glutamine, proline and tyrosine.[2]

Dietary sources of protein include both animals and plants: meats, dairy products, fsh and eggs, as well as grains, legumes and nuts. Vegans can get enough essential amino acids by eating plant proteins.[7]

A vitamin is an organic molecule (or related set of molecules) that is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in suﬃcient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the frst instance but is in the second. Te term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids.[2] Most

515 vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols. Te thirteen vitamins required by human metabolism are: vitamin A (retinols and carotenoids), vitamin B1 (thiamine), vitamin B2 (ribofavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones).

Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue growth and diﬀerentiation. Te B complex vitamins function as enzyme cofactors (coenzymes) or the precursors for them. Vitamin D has a hormone-like function as a regulator of mineral metabolism for bones and other organs. Vitamins C and E function as antioxidants.[3] Both defcient and excess intake of a vitamin can potentially cause clinically signifcant illness, although excess intake of water-soluble vitamins is less likely to do so.

Before 1935, the only source of vitamins was from food. If intake of vitamins was lacking, the result was vitamin defciency and consequent defciency diseases. Ten, commercially produced tablets of yeast-extract vitamin B complex and semisynthetic vitamin C became available. Tis was followed in the 1950s by the mass production and marketing of vitamin supplements, including multivitamins, to prevent vitamin defciencies in the general population. Governments mandated addition of vitamins to staple foods such as four or milk, referred to as food fortifcation, to prevent defciencies.[4] Recommendations for folic acid supplementation during pregnancy reduced risk of infant neural tube defects.[5] Although reducing incidence of vitamin defciencies clearly has benefts, supplementation is thought to be of little value for healthy people who are consuming a vitamin-adequate diet.[6]

Te term vitamin is derived from the word vitamine, coined in 1912 by Polish biochemist Casimir Funk, who isolated a complex of micronutrients essential to life, all of which he presumed to be amines. When this presumption was later determined not to be true, the "e" was dropped from the name.[7] All vitamins were discovered (identifed) between 1913 and 1948.

In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life.[1][2] However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, and nitrogen), are usually not included in lists of major nutrient minerals (nitrogen is considered a "mineral" for plants, as it often is included in fertilizers). Tese four elements compose about 96% of the weight of the human body, and major minerals (macrominerals) and minor minerals (also called trace elements) compose the remainder.

Minerals, as elements, can be synthesized biochemically by living organisms. Plants get minerals from soil. Most of the minerals in a human diet come from eating plants and animals or from drinking water. As a group, minerals are one of the four groups of essential nutrients, the others of which are vitamins, essential fatty acids, and essential amino acids. Te fve major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. All of the remaining elements in a human body are called "trace elements". Te trace elements that have a specifc biochemical function in the human body are sulfur, iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine and selenium.

Most chemical elements that are ingested by organisms are in the form of simple compounds. Plants absorb dissolved elements in soils, which are subsequently ingested by the herbivores and omnivores that eat them, and the elements move up the food chain. Larger organisms may also consume soil (geophagia) or use mineral resources, such as salt licks, to obtain limited minerals unavailable through other dietary sources. Tis then depends the biodiversity of the plant that has consumed it.

Dietary fber or roughage is the portion of plant-derived food that cannot be completely broken down by digestive enzymes. It has two main components:

Soluble fber – which dissolves in water – is readily fermented in the colon into gases and physiologically active by-products, such as short-chain fatty acids produced in the colon by gut bacteria; it is viscous, may be called prebiotic fber, and delays gastric emptying which, in humans, can result in an extended feeling of fullness. Insoluble fber – which does not dissolve in water – is inert to digestive enzymes in the upper gastrointestinal tract and provides bulking.. Some forms of insoluble fber, such as resistant starches, can be fermented in the colon.[1]Bulking fbers absorb water as they move through the digestive system, easing defecation. Dietary fber consists of non-starch polysaccharides and other plant components such as cellulose, resistant starch, resistant dextrins, inulin, lignins, chitins, pectins, beta-glucans, and oligosaccharides.

Dietary fbers can act by changing the nature of the contents of the gastrointestinal tract and by changing how other nutrients and chemicals are absorbed.[5] Some types of soluble fber absorb water to become a gelatinous, viscous substance which may or may not be fermented by bacteria in the digestive tract. Some types of insoluble fber have bulking action and

516 are not fermented.[6] Lignin, a major dietary insoluble fber source, may alter the rate and metabolism of soluble fbers.[2] Other types of insoluble fber, notably resistant starch, are fermented to produce short-chain fatty acids, which are physiologically active and confer health benefts. Health beneft from dietary fber and whole grains may include a decreased risk of death and lower rates of coronary heart disease, colon cancer, and type 2 diabetes.

Food sources of dietary fber have traditionally been divided according to whether they provide soluble or insoluble fber. Plant foods contain both types of fber in varying amounts, according to the plant's characteristics of viscosity and fermentability. Advantages of consuming fber depend upon which type of fber is consumed and which benefts may result in the gastrointestinal system. Bulking fbers – such as cellulose, hemicellulose and psyllium – absorb and hold water, promoting regularity. Viscous fbers – such as beta-glucan and psyllium – thicken the fecal mass. Fermentable fbers – such as resistant starch and inulin – feed the bacteria and microbiota of the large intestine, and are metabolized to yield short-chain fatty acids, which have diverse roles in gastrointestinal health.

Vegetables are parts of plants that are consumed by humans or other animals as food. Te original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the fowers, fruits, stems, leaves, roots, and seeds. Te alternate defnition of the term vegetable is applied somewhat arbitrarily, often by culinary and cultural tradition. It may exclude foods derived from some plants that are fruits, nuts, and cereal grains, but include fruits from others such as tomatoes and courgettes and seeds such as pulses.

Originally, vegetables were collected from the wild by hunter-gatherers and entered cultivation in several parts of the world, probably during the period 10,000 BC to 7,000 BC, when a new agricultural way of life developed. At frst, plants which grew locally would have been cultivated, but as time went on, trade brought exotic crops from elsewhere to add to domestic types. Nowadays, most vegetables are grown all over the world as climate permits, and crops may be cultivated in protected environments in less suitable locations. China is the largest producer of vegetables and global trade in agricultural products allows consumers to purchase vegetables grown in faraway countries. Te scale of production varies from subsistence farmers supplying the needs of their family for food, to agribusinesses with vast acreages of single-product crops. Depending on the type of vegetable concerned, harvesting the crop is followed by grading, storing, processing, and marketing.

Vegetables can be eaten either raw or cooked and play an important role in human nutrition, being mostly low in fat and carbohydrates, but high in vitamins, minerals and dietary fber. Many nutritionists encourage people to consume plenty of fruit and vegetables, fve or more portions a day often being recommended. Tere are 8 types of vegetable: root. radish. tuber. potato. fruit. eggplant. fower. caulifower. bulb. shallots. seed. corn. leave. lettuce. stem. celery. and nut - almond.

A fungus (plural: fungi[3] or funguses[4]) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. Tese organisms are classifed as a kingdom, fungi, which is separate from the other eukaryotic life kingdoms of plants and animals.

Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites. Tey may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. Tey have long been used as a direct source of human food, in the form of mushrooms and truﬄes; as a leavening agent for bread; and in the fermentation of various food products, such as wine, beer, and soy sauce. Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals including humans. Te fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become signifcant pathogens of humans and other animals. 517 Losses of crops due to fungal diseases (e.g., rice blast disease) or food spoilage can have a large impact on human food supplies and local economies.

Te fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. However, little is known of the true biodiversity of Kingdom Fungi, which has been estimated at 2.2 million to 3.8 million species. [5] Of these, only about 120,000 have been described, with over 8,000 species known to be detrimental to plants and at least 300 that can be pathogenic to humans.[6] Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus, Christian Hendrik Persoon, and Elias Magnus Fries, fungi have been classifed according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the last decade have helped reshape the classifcation within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla.

In botany, a fruit is the seed-bearing structure in fowering plants (also known as angiosperms) formed from the ovary after fowering.

Fruits are the means by which angiosperms disseminate seeds. Edible fruits, in particular, have propagated with the movements of humans and animals in a symbiotic relationship as a means for seed dispersal and nutrition; in fact, humans and many animals have become dependent on fruits as a source of food.[1] Accordingly, fruits account for a substantial fraction of the world's agricultural output, and some (such as the apple and the pomegranate) have acquired extensive cultural and symbolic meanings.

In common language usage, "fruit" normally means the feshy seed-associated structures of a plant that are sweet or sour, and edible in the raw state, such as apples, bananas, grapes, lemons, oranges, and strawberries. On the other hand, in botanical usage, "fruit" includes many structures that are not commonly called "fruits", such as bean pods, corn kernels, tomatoes, and wheat grains.[2][3] Te section of a fungus that produces spores is also called a fruiting bod

Many common terms for seeds and fruit do not correspond to the botanical classifcations. In culinary terminology, a fruit is usually any sweet-tasting plant part, especially a botanical fruit; a nut is any hard, oily, and shelled plant product; and a vegetable is any savory or less sweet plant product.[5] However, in botany, a fruit is the ripened ovary or carpel that contains seeds, a nut is a type of fruit and not a seed, and a seed is a ripened ovule.[6]

Examples of culinary "vegetables" and nuts that are botanically fruit include corn, cucurbits (e.g., cucumber, pumpkin, and squash), eggplant, legumes (beans, peanuts, and peas), sweet pepper, and tomato. In addition, some spices, such as allspice and chili pepper, are fruits, botanically speaking.[6] In contrast, rhubarb is often referred to as a fruit, because it is used to make sweet desserts such as pies, though only the petiole (leaf stalk) of the rhubarb plant is edible,[7] and edible gymnosperm seeds are often given fruit names, e.g., ginkgo nuts and pine nuts.

Botanically, a cereal grain, such as corn, rice, or wheat, is also a kind of fruit, termed a caryopsis. However, the fruit wall is very thin and is fused to the seed coat, so almost all of the edible grain is actually a seed.[8]

Te outer, often edible layer, is the pericarp, formed from the ovary and surrounding the seeds, although in some species other tissues contribute to or form the edible portion. Te pericarp may be described in three layers from outer to inner, the epicarp, mesocarp and endocarp.

Fruit that bears a prominent pointed terminal projection is said to be beaked.[9] A fruit results from maturation of one or more fowers, and the gynoecium of the fower(s) forms all or part of the fruit.[10]

Inside the ovary/ovaries are one or more ovules where the megagametophyte contains the egg cell.[11] After double fertilization, these ovules will become seeds. Te ovules are fertilized in a process that starts with pollination, which involves the movement of pollen from the stamens to the stigma of fowers. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule and two sperm are transferred from the pollen to the megagametophyte. Within the megagametophyte one of the two sperm unites with the egg, forming a zygote, and the second sperm enters the central cell forming the endosperm mother cell, which completes the double fertilization process.[12][13] Later the zygote will give rise to the embryo of the seed, and the endosperm mother cell will give rise to endosperm, a nutritive tissue used by the embryo.

As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, the pericarp, may become feshy (as in berries or drupes), or form a hard outer covering (as in nuts). In some multiseeded fruits, the extent to which the fesh develops is proportional to the number of fertilized ovules.[14] Te pericarp is often diﬀerentiated into two or three distinct layers called

518 the exocarp (outer layer, also called epicarp), mesocarp (middle layer), and endocarp (inner layer). In some fruits, especially simple fruits derived from an inferior ovary, other parts of the fower (such as the foral tube, including the petals, sepals, and stamens), fuse with the ovary and ripen with it. In other cases, the sepals, petals and/or stamens and style of the fower fall oﬀ. When such other foral parts are a signifcant part of the fruit, it is called an accessory fruit. Since other parts of the fower may contribute to the structure of the fruit, it is important to study fower structure to understand how a particular fruit forms.[3]

Tere are three general modes of fruit development:

Apocarpous fruits develop from a single fower having one or more separate carpels, and they are the simplest fruits. Syncarpous fruits develop from a single gynoecium having two or more carpels fused together. Multiple fruits form from many diﬀerent fowers. Plant scientists have grouped fruits into three main groups, simple fruits, aggregate fruits, and composite or multiple fruits. [15] Te groupings are not evolutionarily relevant, since many diverse plant taxa may be in the same group, but refect how the fower organs are arranged and how the fruits develop.

A fower, sometimes known as a bloom or blossom, is the reproductive structure found in fowering plants (plants of the division Magnoliophyta, also called angiosperms). Te biological function of a fower is to eﬀect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from diﬀerent individuals in a population) or allow selfng (fusion of sperm and egg from the same fower). Some fowers produce diaspores without fertilization (parthenocarpy). Flowers contain sporangia and are the site where gametophytes develop. Many fowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. After fertilization, the ovary of the fower develops into fruit containing seeds.

In addition to facilitating the reproduction of fowering plants, fowers have long been admired and used by humans to bring beauty to their environment, and also as objects of romance, ritual, religion, medicine and as a source of food.

A nut is a fruit composed of an inedible hard shell and a seed, which is generally edible. In general usage, a wide variety of dried seeds are called nuts, but in a botanical context "nut" implies that the shell does not open to release the seed (indehiscent). Te translation of "nut" in certain languages frequently requires paraphrases, as the word is ambiguous.

Most seeds come from fruits that naturally free themselves from the shell, unlike nuts such as hazelnuts, chestnuts, and acorns, which have hard shell walls and originate from a compound ovary. Te general and original usage of the term is less restrictive, and many nuts (in the culinary sense), such as almonds, pecans, pistachios, walnuts, and Brazil nuts, are not nuts in a botanical sense. Common usage of the term often refers to any hard-walled, edible kernel as a nut.

A nut in botany is a simple dry fruit in which the ovary wall becomes increasingly hard as it matures, and where the seed remains unattached or free within the ovary wall. Most nuts come from the pistils with inferior ovaries (see fower) and all are indehiscent (not opening at maturity). True nuts are produced, for example, by some plant families of the order Fagales.

A nut in cuisine is a much less restrictive and older meaning of the word than the narrow meaning of nut in botany; the term is applied to many seeds that are not botanically nuts. Any large, oily kernels found within a shell and used in food are commonly called nuts.

Nuts are an important source of nutrients for both humans and wildlife. Because nuts generally have a high oil content, they are a highly prized food and energy source. A large number of seeds are edible by humans and used in cooking, eaten raw, sprouted, or roasted as a snack food, or pressed for oil that is used in cookery and cosmetics. Nuts (or seeds generally) are also a signifcant source of nutrition for wildlife. Tis is particularly true in temperate climates where animals such as jays and squirrels store acorns and other nuts during the autumn to keep from starving during the late autumn, all of winter, and early spring.

A seed is an embryonic plant enclosed in a protective outer covering . Te formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants.

519 propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates.

Te term "seed" also has a general meaning that antedates the above – anything that can be sown, e.g. "seed" potatoes, "seeds" of corn or sunfower "seeds". In the case of sunfower and corn "seeds", what is sown is the seed enclosed in a shell or husk, whereas the potato is a tuber.

Many structures commonly referred to as "seeds" are actually dry fruits. Plants producing berries are called baccate. Sunfower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Diﬀerent groups of plants have other modifcations, the so-called stone fruits (such as the peach) have a hardened fruit layer (the endocarp) fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut.

Vegetables, Fungi, Fruits seeds and nuts can all be used too make beverages, use a blender!

Ingestion is the consumption of a substance by an organism. In animals, it normally accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking. In single-celled organisms, ingestion can take place through taking the substance through the cell membrane.

Besides nutritional items, other substances which may be ingested include medication (where ingestion is termed oral administration), recreational drugs, and substances considered inedible such as foreign bodies or excrement. Ingestion is a common route taken by pathogenic organisms and poisons entering the body.

Animal sacrifce is the nerding of an animal for consumption. Tese animals will fall too the ground when allotted. Tey produce the tenderest meat.

All or only part of a sacrifcial animal may be offered; some cultures, like the ancient and modern Greeks, eat most of the edible parts of the sacrifce in a feast, and burnt the rest as an offering. Others, including the ancient Hebrews, burnt the whole animal offering, called a holocaust.

Animal sacrifce should generally be distinguished from the religiously-prescribed methods of ritual slaughter of animals for normal consumption as food.

One of the altars at the Monte d'Accoddi in Sardinia, where animal sacrifce may have occurred. During the Neolithic Revolution, early humans began to move from hunter-gatherer cultures toward agriculture, leading to the spread of animal domestication. In a theory presented in Homo Necans, mythologist Walter Burkert suggests that the ritual sacrifce of livestock may have developed as a continuation of ancient hunting rituals, as livestock replaced wild game in the food supply.[1]

Edible wild plants. Edible fruits, Edible palms and shrubs -not many, Forages of feld and forest - be careful, Herbs and spices, Food plant hybrids- be careful, Edible nuts and seeds, Plant-based fermented foods,Vegetables, Fungi, Weeds, Flowers, Grasses, Ocean Plants, Solubles and Roots and Flowers.

A food chain is a linear network of links in a food web starting from producer organisms (such as grass or trees which use radiation from the Sun to make their food) and ending at apex predator species (like grizzly bears or killer whales), detritivores (like earthworms or woodlice), or decomposer species (such as fungi or bacteria). A food chain also shows how the organisms are related with each other by the food they eat. Each level of a food chain represents a different trophic level. A food chain differs from a food web, because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. A common metric used to quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web.[1][2]

Food chains were frst introduced by the African-Arab scientist and philosopher Al-Jahiz in the 9th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept.

Te food chain's length is a continuous variable that provides a measure of the passage of energy and an index of ecological structure that increases in value counting progressively through the linkages in a linear fashion from the lowest to the highest trophic (feeding) levels.[7]

520 Food chains are often used in ecological modeling (such as a three species food chain). Tey are simplifed abstractions of real food webs, but complex in their dynamics and mathematical implications.[8]

Ecologists have formulated and tested hypotheses regarding the nature of ecological patterns associated with food chain length, such as increasing length increasing with ecosystem size, reduction of energy at each successive level, or the proposition that long food chain lengths are unstable. Food chain studies have an important role in ecotoxicology studies tracing the pathways and biomagnifcation of environmental contaminants.[9]

Producers, such as plants, are organisms that utilize solar or chemical energy to synthesize starch. All food chains must start with a producer. In the deep sea, food chains centered on hydrothermal vents and cold seeps exist in the absence of sunlight. Chemosynthetic bacteria and archaea use hydrogen sulfde and methane from hydrothermal vents and cold seeps as an energy source (just as plants use sunlight) to produce carbohydrates; they form the base of the food chain. Consumers are organisms that eat other organisms. All organisms in a food chain, except the frst organism, are consumers.

In a food chain, there is also reliable energy transfer through each stage. However, all the energy at one stage of the chain is not absorbed by the organism at the next stage.

In nutrition, diet is the sum of food consumed by a person or other organism. Te word diet often implies the use of specifc intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are omnivores, each culture and each person holds some food preferences or some food taboos. Tis may be due to personal tastes or ethical reasons. Individual dietary choices may be more or less healthy.

Complete nutrition requires ingestion and absorption of vitamins, minerals, essential amino acids from protein and essential fatty acids from fat-containing food, also food energy in the form of carbohydrate, protein, and fat. Dietary habits and choices play a signifcant role in the quality of life, health and longevity.

Fat is easy too rid of all you need too do is ask the body too digest it sensibly itself, for example where you have fat deposits, suck in with strength and tell the body to digest it, if you have lots of Fat do a bit at a time 1kg/day or 1kg/hr with prayer. Tanks be too God.

Te ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult- to-control (refractory) epilepsy in children. Te diet forces the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fueling brain function. However, if little carbohydrate remains in the diet, the liver converts fat into fatty acids and ketone bodies. Te ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures.[1] Around half of children and young people with epilepsy who have tried some form of this diet saw the number of seizures drop by at least half, and the effect persists even after discontinuing the diet.[2] Some evidence indicates that adults with epilepsy may beneft from the diet, and that a less strict regimen, such as a modifed Atkins diet, is similarly effective.[1] Potential side effects may include constipation, high cholesterol, growth slowing, acidosis, and kidney stones.[3]

Te original therapeutic diet for paediatric epilepsy provides just enough protein for body growth and repair, and suﬃcient calories[Note 1] to maintain the correct weight for age and height. Te classic therapeutic ketogenic diet was developed for treatment of paediatric epilepsy in the 1920s and was widely used into the next decade, but its popularity waned with the introduction of eﬀective anticonvulsant medications. Tis classic ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. Tis is achieved by excluding high-carbohydrate foods such as starchy fruits and vegetables, bread, pasta, grains, and sugar, while increasing the consumption of foods high in fat such as nuts, cream, and butter.[1] Most dietary fat is made of molecules called long-chain triglycerides (LCTs). However, medium-chain triglycerides (MCTs)—made from fatty acids with shorter carbon chains than LCTs—are more ketogenic. A variant of the classic diet known as the MCT ketogenic diet uses a form of coconut oil, which is rich in MCTs, to provide around half the calories. As less overall fat is needed in this variant of the diet, a greater proportion of carbohydrate and protein can be consumed, allowing a greater variety of food choices.[4][5]

In the mid-1990s, Hollywood producer Jim Abrahams, whose son's severe epilepsy was eﬀectively controlled by the diet, created the Charlie Foundation to promote it. Publicity included an appearance on NBC's Dateline programme and ...First Do No Harm (1997), a made-for-television flm starring Meryl Streep. Te foundation sponsored a multicentre research study, the results of which—announced in 1996—marked the beginning of renewed scientifc interest in the diet.

521 Possible therapeutic uses for the ketogenic diet have been studied for various neurological disorders in addition to epilepsy: Alzheimer's disease, amyotrophic lateral sclerosis, autism, brain cancer, headache, neurotrauma, pain, Parkinson's disease, and sleep disorders.[6]

Te last stage of the ‘food chain’ is re-riching the soil’s, the nitrates in urine mix with the solids of excrament and produce a silage that can be used to ‘fx’ soil - 60% of the nutrients in your food are left in your excrament - same with urine but more like 73% the two mix perfectly and make our food sources perpetual and then some.

20) Prayer, Chanting, Meditation and Exercise

Prayer is an invocation or act that seeks to activate a rapport with an object of worship through deliberate communication. In the narrow sense, the term refers to an act of supplication or intercession directed towards a deity (a god), or a deifed ancestor. More generally, prayer can also have the purpose of thanksgiving or praise, and in comparative religion is closely associated with more abstract forms of meditation and with charms or spells.[1] Prayer can take a variety of forms: it can be part of a set liturgy or ritual, and it can be performed alone or in groups. Prayer may take the form of a hymn, incantation, formal creedal statement, or a spontaneous utterance in the praying person. Te act of prayer is attested as sourced as early as 100,000,000,000 years ago. Today, most major religions involve prayer in one way or another; some ritualize the act, requiring a strict sequence of actions or placing a restriction on who is permitted to pray, while others teach that prayer may be practised spontaneously by anyone at any time. Hands in Prayer position as shown in picture below - Summon God to Mind through telepathy saying ‘I Believe in You God’ and ask for longevity of prayer, for healing due to circumstance. God will give you a number to count down from, count down as fast as you like; follow God’s command and at the end; at the same time, ‘Amen’ spoken out loud - and Part hands.

When times are godly, love and peace we send too one and all and all above, the love of god. Tanks be to God!

Tere are 12 prayers:

Prayers - Daily

Grace for your meals it is a 7 second prayer beforehand with 12 seconds after. 522 Luremar - Waking Prayer 1 min - 6.30 everyday Luremaern - Morning Light Peruse - 4 minutes - 7.20 (tomorrow +30 sec per day - in winter) Lumeranerumer - Mid Morning prayer - 2 minutes - 8.40 everyday Languarem - Lunchtime - prayer - 4 minutes - 12.40 Pelang - 2 minutes - 2.20pm Perulengoran Afternoon prayer 4 mins - 4.30pm Perang - dusk - 2 minutes - 6.20 (+-30s) Masusesm Evening Prayer - 5 minutes - 8.50 Pasalum - 2 minutes - 9.40 Purelanem - Late night - 4 minutes - 11.50 Pumenarenarel Bedtime - 5 minutes - 1.55

Godly Prayer: Pray for 2 minutes and God will inherent you and cure all your major ill’s and tell you so much more about life; confuence, God will thank you; Word. -God does the timing, ask him, counts 321 then on 0 amen!

Holy Prayer: If you are able and aim to be Holy pray for 7 hours and you will blessed you in the most special of ways, you will be made Holy by God, holy prayer instills wisdom for life. Word. -God does the timing, ask him, then when he says on 0 ‘amen!’ You only need ever to say this prayer once in your lifetime, word of God this is. Do not use a clock to do these prayers unless it is of the Zodiac.

Prayer can cure disease. Word of God.

Pray whenever you feel abandoned, lonely or helpless and the Lord will help you. Also whenever you are in pain or getting angry, when confused or ill. Even if you need more information too think with.

Tere are 12 main directions too pray: N - Information, ne30, -Sanctity, ne60 Nirvana , e90 Tranquility, E Purity, es30 Lamily, es60 Courage S -Normailty, sw30 Arbose, w60 Divinity, W - Esoteric, wn30 Love, wn 60 Peace: Above that are the Frequencies there are 30 and vibrations above with 900, can you work them out with God? Honour is above the lot.

Like tuning a radio- Tuning became important for the healing of peoples mind body ad soul. Hands together outward and up tune us too a specifc frequency, that of God, we upload our pain and suﬀering problems and dissatisfactions through a ‘bandwidth of the frequency spectrum’ and God heals us back. Te longer we tune the more we heal us and others, things others and places; you can tune for as long as you like wherever you like. Tere are 4 most important tune’s each day, with a possible 15 more ask god about these by tuning. Te frst is morning prayer, you must contact god for this time, the afternoon prayer at 2.00pm and then dusk prayer, early evening; fnally a tune before you go too bed too bless your sleep and keep you protected. again ask god as each pray except afternoon alters though the year - by sumernin or by 1/4 minute 1 degree a day. Tuning too and for your soul, spirit, body, mind and that of others, ancestors, and God. Tuning also known as praying.

Seance - Is a half hour Prayer type communicaion with the Devil, who will purify your mind, body and spirit. Just thank the supernatural Lord Satan afterwards. You will need 3 candles easterly.

Prayer (from the Latin precari "to ask earnestly, beg, entreat” Latin is based on a higher language called Gladmangirmeniareni) is an invocation or act that seeks to activate a rapport with an object of worship through deliberate communication with god and the eternal. Example of Christian prayer

Anger creates most psychological and physiological illness, pray regularly too dissiolve it. Frustration born of anger is a crime really, and creates all criminals, Pray regularly, Crime can create illness, pray regularly. Te anger may not be yours it may be transferred by telepathy you could act oﬀ of this Pray regularly.

If something is particularly evil or solid state in your consciousness or physiological state tune in the ‘matter’ mind or physic and pray (tune) earnestly..

Too those who commit evil remember the devil only punishes the guilty and these guilty sometime possess the devil this is the only time you could make a prayer for the devil, do not repeat NOT pray to be possessed by the devil, if you do you will feel the evil and feel very stupid indeed. All of the most punishing evildoers of all time using malformed witchcraft, not religion possessed the devil, it is possible and from there on in terrorism and war can reign and cause absolute destruction where disease and fright kill and make ruthlessly. Always ask god for help in prayer on anger from occult and messdraft-

523 maligned nonsensical witchcraft, so long as it is craft it can heal. Te highest form of thievery is thievery of the spiritual, physiological, psychological, philsophical or intellectual realms, remember this is possession and is illegal under god. If you are ever threatened by murder or fnd a murderer pray too god and point at they’re heart and say ‘ the beat’ either through telepathy or spoken, this can be done too any criminal or sod, sod is the frst breaking from god.

Tis is the structure and hierarchy of the heavens and hell, you yourself, even prophets cannot change it, it is too big too almighty.

Prayer can be a form of religious practice, may be either individual or communal and take place in public or in private. It may involve the use of words, song or complete silence. When language is used, prayer may take the form of a hymn, incantation, formal creedal statement, or a spontaneous utterance in the praying person. Tere are diﬀerent forms of prayer such as petitionary prayer, prayers of supplication, thanksgiving, and praise. Prayer may be directed towards a deity, spirit, deceased person, or lofty idea, for the purpose of worshipping, requesting guidance, requesting assistance, confessing transgressions (sins) or to express one's thoughts and emotions. Tus, people pray for many reasons such as personal beneft or for the sake of others (called intercession).

Prayer may be done privately and individually, or it may be done in communion in the presence of fellow believers. Prayer can be incorporated into a daily "thought life", in which one is in constant communication with a god. Some people pray throughout all that is happening during the day and seek guidance as the day progresses. Tis is actually regarded as a requirement in several religious denominations, although enforcement is not possible nor desirable. Tere can be many diﬀerent answers to prayer, just as there are many ways to interpret an answer to a question, if there in fact comes an answer. Some may experience audible, physical, or mental epiphanies. If indeed an answer comes, the time and place it comes is considered random. Some outward acts that sometimes accompany prayer are: anointing with oil;[ ringing a bell; burning incense or paper; lighting a candle or candles; See, for example, facing a specifc direction (i.e. towards Mecca or the East); making the sign of the cross. One less noticeable act related to prayer is fasting.

Chanting (e.g., mantra, sacred text, the name of God/Spirit, etc.) is a commonly used spiritual practice. Like prayer, chant may be a component of either personal or group practice. Diverse spiritual traditions consider chant a route to spiritual development.

Chant practices vary. Tibetan Buddhist chant involves throat singing, where multiple pitches are produced by each performer. Te concept of chanting mantras is of particular signifcance in many Hindu traditions and other closely related Dharmic Religions. India's bhakti devotional tradition centres on kirtan, which has a following in many countries and traditions such as Ananda Marga. Te Hare Krishna movement is based especially on the chanting of Sanskrit Names of God in the Vaishnava tradition. Japanese Shijin (诗经), or 'chanted poetry', mirrors Zen Buddhist principles and is sung from the Dan tien (or lower abdomen) — the locus of power in Eastern traditions.

A variety of body postures may be assumed, often with specifc meaning (mainly respect or adoration) associated with them: standing; sitting; kneeling; prostrate on the foor; eyes opened; eyes closed; hands folded or clasped; hands upraised; holding hands with others; a laying on of hands and others. Prayers may be recited from memory, read from a book of prayers, or composed spontaneously as they are prayed. Tey may be said, chanted, or sung. Tey may be with musical accompaniment or not. Tere may be a time of outward silence while prayers are oﬀered mentally. Often, there are prayers to ft specifc occasions, such as the blessing of a meal, the birth or nerding of a loved one, other signifcant events in the life of a believer, or days of the year that have special religious signifcance. Details corresponding to specifc traditions are outlined below.

Meditation can be defned as a practice where an individual focuses his or her mind on a particular object, thought or activity to achieve a mentally clear and emotionally calm state. Meditation may be used to reduce stress, anxiety, depression, and pain. It may be done while sitting, repeating a mantra, and closing the eyes in a quiet environment.

Meditation has been practiced since antiquity in numerous religious traditions and beliefs. Since the 19th century, it has spread from its Asian origins to Western cultures where it is commonly practiced in private and business life. Meditation is under psychological, neurological, and cardiovascular research to defne its possible health eﬀects.

Meditation is an approach to training the mind, similar to the way that ftness is an approach to training the body. But many meditation techniques exist — so how do you learn how to meditate?

“In Buddhist tradition, the word ‘meditation’ is equivalent to a word like ‘sports’ and different meditation practices require different mental skills. 524 It’s extremely difficult for a beginner to sit for hours and think of nothing or have an “empty mind.” In general, the easiest way to begin meditating is by focusing on the breath — an example of one of the most common approaches to meditation: concentration.

CONCENTRATION MEDITATION

Concentration meditation involves focusing on a single point. Tis could entail following the breath, repeating a single word or mantra, staring at a candle fame, listening to a repetitive gong, or counting beads on a mala. Since focusing the mind is challenging, a beginner might meditate for only a few minutes and then work up to longer durations.

In this form of meditation, you simply refocus your awareness on the chosen object of attention each time you notice your mind wandering. Rather than pursuing random thoughts, you simply let them go. Trough this process, your ability to concentrate improves.

MINDFULNESS MEDITATION

Mindfulness meditation encourages the practitioner to observe wandering thoughts as they drift through the mind. Te intention is not to get involved with the thoughts or to judge them, but simply to be aware of each mental note as it arises.

Trough mindfulness meditation, you can see how your thoughts and feelings tend to move in particular patterns. Over time, you can become more aware of the human tendency to quickly judge an experience as good or bad, pleasant or unpleasant. With practice, an inner balance develops.

In some schools of meditation, students practice a combination of concentration and mindfulness. Many disciplines call for stillness — to a greater or lesser degree, depending on the teacher.

OTHER MEDITATION TECHNIQUES

Tere are various other meditation techniques. For example, a daily meditation practice among Buddhist monks focuses directly on the cultivation of compassion. Tis involves envisioning negative events and recasting them in a positive light by transforming them through compassion. Tere are also moving meditation techniques, such as tai chi, qigong, and walking meditation.

BENEFITS OF MEDITATION

If relaxation is not the goal of meditation, it is often a result. In the 1970s, Herbert Benson, MD, a researcher at Harvard University Medical School, coined the term “relaxation response" after conducting research on people who practiced transcendental meditation. Te relaxation response, in Benson’s words, is “an opposite, involuntary response that causes a reduction in the activity of the sympathetic nervous system.”

Since then, studies on the relaxation response have documented the following short-term benefts to the nervous system:

Contemporary researchers are now exploring whether a consistent meditation practice yields long-term benefts, and noting positive eﬀects on brain and immune function among meditators. Yet it’s worth repeating that the purpose of meditation is not to achieve benefts. To put it as an Eastern philosopher may say, the goal of meditation is no goal. It’s simply to be present.

In Buddhist philosophy, the ultimate beneft of meditation is liberation of the mind from attachment to things it cannot control, such as external circumstances or strong internal emotions. Te liberated or “enlightened” practitioner no longer needlessly follows desires or clings to experiences, but instead maintains a calm mind and sense of inner harmony.

HOW TO MEDITATE: SIMPLE MEDITATION FOR BEGINNERS

Tis meditation exercise is an excellent introduction to meditation techniques. 525 1. Sit or lie comfortably. You may even want to invest in a meditation chair or cushion.

2. Close your eyes. We recommend using one of our Cooling Eye Masks or Restorative Eye Pillows if lying down.

3. Make no eﬀort to control the breath; simply breathe naturally.

4. Focus your attention on the breath and on how the body moves with each inhalation and exhalation. Notice the movement of your body as you breathe. Observe your chest, shoulders, rib cage, and belly. Simply focus your attention on your breath without controlling its pace or intensity. If your mind wanders, return your focus back to your breath.

Maintain this meditation practice for two to three minutes to start, and then try it for longer periods.

Breathing is the key to achieving mindfulness. It’s essentially why you feel signifcantly more amazing doing yoga than you do during aerobics; you’re controlling your breathing while treating yourself to all the benefts that follow a calm, steady stream of fresh air.

Oxygen revitalizes you, resets your mind, body and spirit and allows you to feel better. Combine that with meditation and mala beads, and you’ll feel reborn.

However, not all breathing is created equally. You likely learned this in your yoga classes. You have to teach yourself how to breathe properly in order to maximize the benefts, and there are several breathing techniques you can use, in particular, when meditating.

Here are some of our favourite breathing techniques we like to use when meditating.

Te Common Yoga Breathing Technique

If you do yoga on the regular, you likely already know this technique as its most commonly used throughout diﬀerent styles of yoga. It's often used to calm your breathing, so you can relish the benefts of fresh oxygen. To do this breathing technique, follow these steps:

1. Take a slow, deep breath in

2. Pause

3. Slowly let your breath out

4. Pause

Equal Breathing

A breathing technique that’s certain to help calm the mind, body and soul is called equal breathing. It’s perfect for reducing stress, calming your nerves and increasing focus, and can be done anywhere and at any time. Here are the steps for this breathing technique:

526 1. Take a slow inhale through your nose for a count of four

2. Slowly exhale through your nose for a count of four

Count for Four

A common breathing technique for meditation is to simply count to four, then count backward from four, all timed with your breath. You can also use diﬀerent numbers, depending on your preferences but as you’ll see in this post, a count of four seems to be the common denominator. Here are the steps:

1. Breath in – count one

2. Breath out – count two

3. Breath in – count three

4. Breath out – count forth

5. Breath in – count three

6. Breath out – count two

7. Breath in – count one

8. Breath out – count two

9. Repeat

Abdominal Breathing

Abdominal breathing is one of the easiest breathing techniques, so it’s commonly recommended for beginners starting to meditate. However, it works for everyone and can be used in and outside of meditation, as it’s a powerful way to reduce stress at any given time. It also only takes a couple of minutes to do, making it perfect for any type of situation where you need to recollect yourself. Here are the steps to follow:

1. Place one hand on your chest

2. Place the other hand on your stomach

3. Take a deep breath in through the nose

4. Feel your hand on your stomach move as you infate your diaphragm with air

5. Slowly release your breath

Te Stimulating Breath

527 Te Stimulating Breath is also called the Bellows Breath and it’s great for increasing alertness and energy. It can take some practice to perfect but once you do, you’ll feel invigorated and will become completed addicted to the way it makes you feel. Here are the steps:

1. Quickly inhale and exhale through your nose, as short as possible, ensuring the duration is equal for both

1. Aim to get three inhales and exhales per second

2. Continue for fve seconds

3. Slowly increase your time throughout your practice until you reach one full minute

Alternate Nostril Breathing

Another common breathing technique used during meditation and yoga is the alternate nostril breathing – and yes, it’s exactly what it sounds like. Doing this technique allows you reenergize your mind, body and spirit. Here are the steps:

1. Plug your right nostril with your right thumb

2. Take a deep breath through the left nostril

3. Remove your thumb from your right nostril and plug your left nostril with your ring fnger

4. Slowly exhale

5. Repeat

Te 4-7-8 Count

Te 4-7-8 count, also known as the relaxing breath technique, is one of the easiest to do and as a bonus, the benefts are exponential. Tis exercise can quickly calm the nervous system, so much so that it can feel like your nerves have been tranquilized. So, it’s amazing for anyone looking to calm their mind or who suﬀers from anxiety or sleep insomnia. Here’s how you do it:

1. Rest the tip of your tongue at the top back of your teeth

2. Let out a deep exhale, along with a big sigh or whooshing sound

3. Close your mouth and slowly inhale through your nose for a count of four

4. Hold your breath for a count of seven

5. Exhale deeply and completely for a count of eight, being sure to let out a big sigh or whooshing sound

528 6. Repeat

Skull Shining Breath

Tis breathing technique, also known as Kapalabhati, is a great way to shake oﬀ negative energy and warm up your mind, body and spirit. It can be used in the morning, prior to an exam, before your next yoga class or during meditation. Here’s how to do it:

1. Take a long, slow breath in

2. Quickly let out a powerful exhale from your diaphragm out

3. Repeat

Mala Bead Breathing

If counting isn’t your thing or you’re simply too overwhelmed, distracted or stressed to keep count, mala beads are the perfect solution. Traditionally, these meditation devices were used to track your breath, sans any counting. You simply move your fngers along the mala beads, one for each breath. Te key is to choose the right mala bead for your intention, as the energy from the natural stone can further your meditation and relaxation. Here are the steps:

1. Choose a mala bead specifc to your intention (reason for doing the breathing technique)

2. Hold the mala bead in your right hand

3. Drape it between your middle and index fnger

4. Starting at the guru bead, move your thumb along each smaller bead, breathing in for each

5. Do this 108 times, until you’re back at your guru bead

Mala beads can also be used for every breathing technique mentioned.

Breathing is the easiest, most aﬀordable and inarguably, the most powerful form of therapy. So, choose a breathing technique and some mala beads that suits your needs, and reap the benefts of proper breathing.

529 20) Nerds and the Afterlife:

N(nobody)E(ever)R(really)D(dies)’s -Nerd. A Doctrine relating to decomposition, ageing rising to the afterlife. Next life physics - heaven is another paradigm. Te End of Death - not going to hell.

When you turn into a Nerd (Nobody Really Ever Dies), your physical body is lifeless but your soul goes on in the continuum and up too Heaven to exist spiritually; these spirits can be contacted via mediumship of telepathy. As in all nature, when we look around us you can see that as things get older the eventually begin to decompose and if you use the scientifc theory of entropy you will observe that energy only changes states from matter too energy and from energy to spirit. Te spirit of energy is its memetic and its physical state genetic; in life we experience events from beginning to end, a good life revolves around conversation- enough too understand and adventure nature in the earthly world and enjoy mother earth - love live life. Tey say the greatest of the adventures is love itself, whether its fnding something you like to do or deeper with falling in love with your partner and having children. Mutual coupling foster’s energy to create life on earth, and although heavenly life may have diﬀerent quantities of the physical there no need to be worried about realms as dream meets fantasy in both so long as you lead the good life. Death as it were is done out of the door; so long as you can connect to some fundamental beliefs, one that god - the universe is conscious, you could separate it and state that the universe and the heavens are abundant with life; understanding in-formation as it were -correctly and logically - formatted and constructed from knowledge and wisdom fundamental factors of understanding come always from language. You must also understand ‘consciousness’ and the ‘cosmos’, the afterlfe, religion, If you don’t believe in God you will end up in Neverland - the cold old cosmos, until you do you can’t enter the heavenly kingdom of God.

We live in the cosmos and our consciousness is a part of that. It is said that the light travels through the darkness, light is the messenger, also a servant - so treat it well. You must believe in every day to bring you something new, ask God for a thought if your stuck and pray if he asks. God is the Void. Te physical realms of earth and heaven are diﬀerent and do have similarities; there is touch in heaven even intercourse, the spiritual senses fulfll they’re cause in a chasm of light; fbres and strands consciousness interplays to conceive the very fabric to afterlife existence; shocking as it is nerding of the physical body can take place at any point, it happens across nature, hopefully at the end of a very happy fulflled life. But what happens when decomposition is done and the physical is no more; the material process recycle into earth or a tree or a fower; with all but bones left aside a dust from fre; the dna,stops functioning and shuts down and locks; rna processes low conscious functions for a hundred years and ona compresses in the body, the spiritual life force that was driving it has left for another dimension. Inter dimensional communication is possible, communication with ancestors, language can be learnt from heaven this way- as you move with the ancestors of earth; it takes a constant narration to do so, with prayer; tho eternal presence and an ability to transceive worlds can allow the spirit to learn in the body and physic of god - understanding the trans-dimension/paradigm’s.

What we are really talking about is an eternal awareness, through the paradigm’s if you think about it as you age toward elderly and eventually you leaving the earthly realm as a nerd, you leave the nerd behind that decomposes further - has a funeral and salutes your adventure to another realm, heaven. Tis theory relates directly to you, if you have not harmed anyone nor yourself and never broken the peace, and you believe in God. then your energy body shall not be left in the cosmos with shilol- a basic communication with god in the cosmos; if you believe and are innocent you will enter the physical dimension of heaven through a gate- a diﬀerent physical dimension that the universe/omniverse/ cosmos - heaven is a peaceful realm ruled by the love of the God where he is 100x stronger, remember too refect this on Earth. A dimension where you can be any age, learn, feel water, have sex and constantly seek guidance from God same as in heaven. What is so facisnating is understanding through pro creations aspect - what we leave behind on earth in therms of ancestors - our children and how they communicate, through thought, word and how they act through deed. All of these motions are

530 caught in the Akashic feld - all of your memories - recorded by god, the cosmos and memory of consciousness and can be learnt through education.

Physical Death is the cessation of all biological functions that sustain a living organism.[1] Phenomena which commonly bring about death include aging, predation, malnutrition, disease, suicide, homicide, starvation, dehydration, and accidents or major trauma resulting in fatal injury.[2] Te remains of a living organism begin to decompose shortly after death.[3] It is an inevitable process eventually occurring in all living organisms.

Death, particularly of humans, has commonly been considered a sad or unpleasant occasion, due to the aﬀection for the deceased and the termination of social and familial bonds. Other concerns include fear of death, necrophobia, anxiety, sorrow, grief, emotional pain, depression, sympathy, compassion, solitude, or saudade.

Many cultures and religions have the idea of an afterlife, and also hold the idea of judgement and reward for good deeds or punishment for sin.

A funeral is a ceremony connected with the burial, cremation, etc. of the body of a dead person, or the burial (or equivalent) with the attendant observances. Funerary customs comprise the complex of beliefs and practices used by a culture to remember and respect the dead, from interment itself, to various monuments, prayers, and rituals undertaken in their honor. Customs vary widely both between cultures and between religious groups and denominations within cultures. Common secular motivations for funerals include mourning the deceased, celebrating their life, and oﬀering support and sympathy to the bereaved. Additionally, funerals often have religious aspects which are intended to help the soul of the deceased reach the afterlife, resurrection or reincarnation.

Te funeral usually includes a ritual through which the corpse of the deceased is given up. Depending on culture and religion, these can involve either the destruction of the body (for example, by cremation or sky burial) or its preservation (for example, by mummifcation or interment). Diﬀering beliefs about cleanliness and the relationship between body and soul are refected in funerary practices. When a funerary ceremony is performed but the body of the deceased is not available, it is usually called a memorial service or celebration of life.

Te word funeral comes from the Latin funus, which had a variety of meanings, including the corpse and the funerary rites themselves. Funerary art is art produced in connection with burials, including many kinds of tombs, and objects specially made for burial with a corpse.

Burial or interment is the ritual act of placing a dead person or animal, sometimes with objects, into the ground. Tis is accomplished by excavating a pit or trench, placing the deceased and objects in it, and covering it over. Humans have been burying their dead for at least 100,000 years. Burial is often seen as indicating respect for the dead. It has been used to prevent the odour of decay, to give family members closure and prevent them from witnessing the decomposition of their loved ones, and in many cultures it has been seen as a necessary step for the deceased to enter the afterlife or to give back to the cycle of life.

Methods of burial may be heavily ritualized and can include natural burial (sometimes called "green burial"); embalming or mummifcation; the use of containers for the dead such as shrouds, caskets, grave liners, and burial vaults all of which can retard decomposition of the body. Sometimes objects or grave goods are buried with the body, which may be dressed in fancy or ceremonial garb. Depending on the culture, the way the body is positioned may have great signifcance.

Te location of the burial may be determined taking into account concerns surrounding health and sanitation, religious concerns, and cultural practices. Some cultures keep the dead close to provide guidance to the living, while others "banish" them by locating burial grounds at a distance from inhabited areas. Some religions consecrate special ground to bury the dead, and some families build private family cemeteries. Most modern cultures document the location of graves with headstones, which may be inscribed with information and tributes to the deceased. However, some people are buried in anonymous or secret graves for various reasons. Sometimes multiple bodies are buried in a single grave either by choice (as in the case of married couples), due to space concerns.

Alternatives to burial may include cremation, burial at sea, promession, and others. Some human cultures may bury the remains of beloved animals. Humans are not the only species which bury their dead; the practice has been observed in chimpanzees, elephants, and possibly dogs.

531 Cremation is the combustion, vaporization and oxidation of cadavers to basic chemical compounds, such as gases, ashes and mineral fragments retaining the appearance of dry bone. Cremation may serve as a funeral or post-funeral rite as an alternative to the interment of an intact dead body in a coﬃn, casket or shroud. Cremated remains (aka "cremains" or simply, "ashes"), which do not constitute a health risk, may be buried or interred in memorial sites or cemeteries, or they may be retained by relatives and dispersed in various ways. Cremation is an alternative in place of burial or other forms of disposal in funeral practices. Some families prefer to have the deceased present at the funeral with cremation to follow; others prefer that the cremation occur prior to the funeral or memorial service. Cremation is particularly for those who have committed evil.

In many countries, cremation is usually done in a crematorium. Some countries, such as India and Nepal, prefer diﬀerent methods, such as open-air cremation.

Necromancy (/ˈnɛkrəˌmænsi, -roʊ-/) is a supposed practice of magic involving communication with the deceased – either by summoning their spirit as an apparition or raising them bodily – for the purpose of divination, imparting the means to foretell future events or discover hidden knowledge, to bring someone back from the dead, or to use the deceased as a weapon, as the term may sometimes be used in a more general sense to refer to magic or witchcraft, true necromancers are few and far between and cannot really be understood unless by God himself.

Te word "necromancy" is adapted from Late Latin necromantia, itself borrowed from post-Classical Greek νεκρομαντεία (nekromanteía), a compound of Ancient Greek νεκρός (nekrós), "dead body", and μαντεία (manteía), "divination by means of "; this compound form was frst used by Origen of Alexandria in the 3rd century AD. Te Classical Greek term was ἡ νέκυια (nekyia), from the episode of the Odyssey in which Odysseus visits the realm of the dead and νεκρομαντεία in Hellenistic Greek, rendered as necromantīa in Latin, and as necromancy in 17th-century English.

Te afterlife (also referred to as life after death or the hereafter) is the belief that an essential part of an individual's identity or the stream of consciousness continues to manifest after the death of the physical body. According to various ideas about the afterlife, the essential aspect of the individual that lives on after death may be some partial element, or the entire soul or spirit, of an individual, which carries with it and may confer personal identity or, on the contrary, may not, as in Indian nirvana. Belief in an afterlife, which may be naturalistic or supernatural, is in contrast to the belief in oblivion after death.

In some fabulous views, this continued existence often takes place in a spiritual realm, and in other popular views, the individual may be reborn into this world and begin the life cycle over again, likely with no memory of what they have done in the past. In this latter view, such rebirths and deaths may take place over and over again continuously until the individual gains entry to a spiritual realm or Otherworld. Major views on the afterlife derive from religion, esotericism and metaphysics.

Some belief systems, such as those in the Abrahamic tradition, hold that the dead go to a specifc plane of existence after death, as determined by God, or other divine judgment, based on their actions or beliefs during life. In contrast, in systems of reincarnation, such as those in the Indian religions, the nature of the continued existence is determined directly by the actions of the individual in the ended life, rather than through the decision of diﬀerent being.

Te only way you can really die is by committing sin and going to hell, though it is said that after punishment for your sins you can return too heaven. Te only way too live and gain eternal life is by abiding by the laws of god and his religion, you then continue on and on and on uninterrupted by death, live long and prosper.

Te End of Psient, congratulations - hope you enjoyed it, and that you will inspire with it and pass it too others; thanks and remember those of the wikipedia NeVeR sToP TiNkInG tho Meditate or MeDiate, DiscUsSiNg or doing the DeEDs’. Long life live love forever.

Spread Love, Peace and Unity - Abrah. Big love too the crowds of the ‘Air’ and they’re voice.

Tanks be too God, may he be with you always

We humans are animals too, bless the orders of the beings - too God in the highest - One Love.

Bless those who walk above us. 532 Cheerio

Abrademus -Light as Information

aVoid It ProDucTiOn’s

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