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Thales

Thales

Thales

For other uses, see Thales (disambiguation). May 28, 585 BC.[6] Laërtius quotes the chron- icle of Apollodorus of as saying that Thales died at the age of 78 in the 58th (548–545 BC), Thales of (/ˈθeɪliːz/; Greek: Θαλῆς (ὁ Μιλή- σιος), Thalēs; c. 624 – c. 546 BC) was a pre-Socratic and attributes his death to heat stroke while watching the Games. Greek from Miletus in Minor, and one of the Seven Sages of . Many, most notably Diogenes Laërtius states that (“according to , regard him as the first philosopher in the Greek and Douris and ") Thales’ parents were Ex- tradition.[1] Aristotle reported Thales’ about amyes and Cleobuline, then traces the family back the of – that the originating of to , a mythological Phoenician prince of Tyre. nature was a single material substance: . Diogenes then delivers conflicting reports: one that According to , “Western be- Thales married and either fathered a son (Cybisthus or gins with Thales.”[2] Thales attempted to explain natu- Cybisthon) or adopted his nephew of the same name; ral phenomena without reference to mythology and was the second that he never married, telling his mother as tremendously influential in this respect. Almost all of a young man that it was too early to marry, and as an the other Pre-Socratic follow him in at- older man that it was too late. had earlier told tempting to provide an explanation of ultimate substance, this version: visited Thales and asked him why he change, and the existence of the world without reference remained single; Thales answered that he did not like the to mythology. Those philosophers were also influential idea of having to worry about children. Nevertheless, sev- eral years later, anxious for family, he adopted his nephew and eventually Thales’ rejection of mythological expla- [7] nations became an essential idea for the scientific revolu- Cybisthus. tion. He was also the first to define general and Thales involved himself in many activities, taking the role set forth hypotheses, and as a result has been dubbed the of an innovator. Some say that he left no , others “Father of ,” though it is argued that Democritus say that he wrote On the and On the . (No is actually more deserving of this title.[3][4] attributed to him has survived.) Diogenes Laër- In , Thales used to solve problems tius quotes two letters from Thales: one to Pherecydes such as calculating the height of and the dis- of Syros offering to review his on , and one tance of ships from the shore. He is credited with the to Solon, offering to keep him company on his sojourn from Athens. Thales identifies the Milesians as Athenian first use of deductive reasoning applied to geometry, by [8] deriving four corollaries to Thales’ . As a result, colonists. he has been hailed as the first true and is the first known individual to whom a mathematical dis- covery has been attributed.[5] 1.2 Business

1

The current historical consensus is that Thales was born in the of Miletus around the mid 620s BC. Miletus was an Ionian city on the western coast of Asia Minor (in what is today Aydin Province of ), near the mouth of the Maeander River.

1.1 Background

The dates of Thales’ life are not exactly known, but are roughly established by a few dateable events mentioned in the sources. According to Herodotus (and determination An mill and an olive press dating from Roman in by modern methods) Thales predicted the solar of Capernaum, Israel.

1 2 1 LIFE

Several anecdotes suggest that Thales was not solely a another . Whether Thales was present at the battle is thinker but was also involved in business and . not known, nor are the exact terms of the prediction, but One story recounts that he bought all the olive presses in based on it the and made immedi- Miletus after predicting the weather and a harvest ately, swearing a blood oath. for a particular year. In another version of the same story, The Medes were dependencies of the under Aristotle explains that Thales reserved presses ahead of Cyrus. now sided with the Medes against the at a discount only to rent them out at a high price Persians and marched in the direction of (with far when demand peaked, following his predictions of a par- fewer men than he needed). He was stopped by the river ticularly good harvest. This first version of the story Halys, then unbridged. This time he had Thales with him, would constitute the first and use of futures, perhaps by invitation. Whatever his status, the king gave whereas the second version would be the first creation and the problem to him, and he got the army across by digging use of options. Aristotle explains that Thales’ objective a diversion upstream so as to reduce the flow, making it in doing this was not to enrich himself but to prove to his possible to ford the river. The channels ran around both Milesians that philosophy could be useful, contrary sides of the camp. to what they thought.[9] The two armies engaged at in . As the battle was indecisive but paralyzing to both sides, Croesus 1.3 Politics marched home, dismissed his mercenaries and sent emis- saries to his dependents and allies to ask them to dispatch Thales’ political life had mainly to do with the involve- fresh troops to . The issue became more pressing ment of the in the defense of against the when the Persian army showed up at Sardis. Diogenes growing power of , who were then new to the Laertius[11] tells us that Thales gained fame as a coun- region. A king had come to power in neighboring , selor when he advised the Milesians not to engage in a Croesus, who was somewhat too aggressive for the size of symmachia, a “fighting together”, with the Lydians. This his army. He had conquered most of the states of coastal has sometimes been interpreted as an alliance, but a ruler Anatolia, including the of the Ionians. The story is does not ally with his subjects. [10] told in Herodotus. Croesus was defeated before the city of Sardis by Cyrus, The Lydians were at war with the Medes, a remnant of who subsequently spared Miletus because it had taken no the first wave of Iranians in the region, over the issue of action. Cyrus was so impressed by Croesus’ and refuge the Lydians had given to some Scythian soldiers his connection with the sages that he spared him and took of fortune inimical to the Medes. The war endured for his advice on various . five years, but in the sixth an eclipse of the (men- The Ionians were now free. Herodotus says that Thales tioned above) spontaneously halted a battle in advised them to form an Ionian state; that is, a bouleu- (the Battle of Halys). terion (“deliberative body”) to be located at in the center of . The Ionian cities should be demoi, or “districts”. Miletus, however, received favorable terms from Cyrus. The others remained in an of 12 cities (excluding Miletus now), and were subjugated by the Persians. While Herodotus reported that most of his fellow believe that Thales did divert the river Halys to assist King Croesus’ military endeavors, he himself finds it doubtful.[12]

1.4 Sagacity

Diogenes Laertius[13] tells us that the Seven Sages were created in the archonship of Damasius at Athens about 582 BC and that Thales was the first sage. The same story, however, asserts that Thales emigrated to Miletus. There is also a report that he did not become a student of nature Total eclipse of the Sun until after his political career. Much as we would like to have a date on the seven sages, we must reject these stories It seems that Thales had predicted this . The and the tempting date if we are to believe that Thales was Seven Sages were most likely already in existence, as a native of Miletus, predicted the eclipse, and was with Croesus was also heavily influenced by Solon of Athens, Croesus in the campaign against Cyrus. 2.1 Water as a first principle 3

stamp of what it is in itself. Aristotle[17] characterizes most of the philosophers “at first” (πρῶτον) as thinking that the “principles in the form of matter were the only principles of all things”, where “principle” is , “matter” is (“wood” or “matter”, “material”) and “form” is eidos. Arche is translated as “principle”, but the two words do not have precisely the same meaning. A principle of something is merely prior (related to pro-) to it either chronologically or logically. An arche (from ἄρχειν, “to rule”) dominates an object in some way. If the arche is taken to be an origin, then specific is implied; that is, B is supposed to be characteristically B just be- The Ionic Stoa on the Sacred Way in Miletus cause it comes from A, which dominates it. The archai that Aristotle had in in his well-known passage on the first Greek are not necessarily Thales received instruction from an Egyptian priest. It chronologically prior to their objects, but are constituents was fairly certain that he came from a wealthy, established of it. For example, in objects are composed family, in a class which customarily provided higher edu- of , , fire and water, but those elements do not cation for their children. Moreover, the ordinary citizen, disappear with the production of the object. They remain unless he was a seafaring man or a merchant, could not as archai within it, as do the atoms of the atomists. afford the grand tour in , and did not consort with noble lawmakers such as Solon. What Aristotle is really saying is that the first philoso- phers were trying to define the substance() of which all Thales participated in some games, most likely material objects are composed. As a matter of fact, that is Panhellenic, in which he won a bowl twice. He exactly what modern scientists are attempting to accom- dedicated it to at . As he was not known to plish in nuclear , which is a second why have been athletic, his event was probably declamation, Thales is described as the first western . and it may have been victory in some specific phase of this event that led to his sagacious designation. 2.1 Water as a first principle

2 Thales’ most famous philosophical position was his cosmological thesis, which comes down to us through The Greeks often invoked idiosyncratic explanations a passage from Aristotle's .[18] In the work of natural phenomena with reference to the will of Aristotle unequivocally reported Thales’ hypothesis about anthropomorphic and heroes. Instead, Thales aimed the nature of matter – that the originating principle of na- to explain natural phenomena via rational hypotheses that ture was a single material substance: water. Aristotle then referenced natural processes themselves. For example, proceeded to proffer a of conjectures based on rather than assuming that were the result of his own observations to lend some credence to why Thales supernatural whims Thales explained them by hypothe- may have advanced this idea (though Aristotle didn’t hold sizing that the Earth floats on water and that earthquakes it himself). Aristotle considered Thales’ position to be occur when the Earth is rocked by waves. roughly the equivalent to the later ideas of Anaximenes, Thales was a hylozoist (one who thinks that matter is who held that everything was composed of air. alive).[14] That interpretation by later commentators— Aristotle laid out his own thinking about matter and form that Thales treated matter as alive—may have been which may shed some on the ideas of Thales, in substituted for his thinking that the properties of na- Metaphysics 983 b6 8–11, 17–21. (The passage contains ture arise directly from material processes. The lat- words that were later adopted by science with quite dif- ter thesis is more consistent with modern ideas of how ferent meanings.) properties arise as emergent characteristics of those complex systems involved in the processes of “That from which is everything that exists and and developmental change. from which it first becomes and into which it Thales, according to Aristotle, asked what was the na- is rendered at last, its substance remaining un- ture (Greek Arche) of the object so that it would be- der it, but transforming in qualities, that they have in its characteristic way. (φύσις) comes from say is the element and principle of things that phyein (φύειν), “to grow”, related to our word “be”.[15] are. …For it is necessary that there be some (G)natura is the way a thing is “born”,[16] again with the nature (φύσις), either one or more than one, 4 2 THEORIES

from which become the other things of the ob- on the promontory of and believed to be ordained ject being saved... Thales the founder of this by the ancestral kindred of , the of the ). type of philosophy says that it is water.” He called for the Ionian mercantile states participating in this ritual to convert it into a democratic under In this quote we see Aristotle’s depiction of the problem the protection of Poseidon that would hold off the of change and the definition of substance. He asked if an of pastoral Persia. Feldman concludes that Thales saw object changes, is it the same or different? In either case “that water was a revolutionary leveler and the elemen- how can there be a change from one to the other? The an- tal factor determining the subsistence and business of the [21] [21] swer is that the substance “is saved”, but acquires or loses world” and “the common channel of states.” different qualities (πάθη, the things you “experience”). Feldman considers Thales’ environment and holds that Aristotle conjectured that Thales reached his conclusion Thales would have seen tears, sweat, and blood as grant- by contemplating that the “nourishment of all things is ing value to a person’s work and the means how life giv- moist and that even the hot is created from the wet and ing commodities travelled (whether on bodies of water or by it.” While Aristotle’s conjecture on why Thales through the sweat of slaves and pack-animals). He would held water was the originating principle of water is his have seen that minerals could be processed from water own thinking, his statement that Thales held it was water such as life-sustaining salt and taken from rivers. He is generally accepted as genuinely originating with Thales would’ve seen fish and other food stuffs gathered from it. and he is seen as an incipient matter-and-formist. Feldman points out that Thales held that the lodestone was alive as it drew metals to itself. He holds that Thales [19] Homericus states that Thales drew his con- “living ever in sight of his beloved sea” would see water clusion from seeing moist substance turn into air, slime seem to draw all “traffic in wine and oil, milk and honey, and earth. It seems likely that Thales viewed the Earth juices and dyes” to itself, leading him to “a vision of the as solidifying from the water on which it floated and the melting into a single substance that was value- oceans that surround it. less in itself and still the source of wealth.”[21] Feldman Writing centuries later Diogenes Laertius also states that concludes that for Thales "...water united all things. The Thales taught “Water constituted (ὑπεστήσατο, 'stood social significance of water in the time of Thales induced under') the principle of all things.”[20] him to discern through hardware and dry-, through soil and sperm, blood, sweat and tears, one fundamental fluid stuff...water, the most commonplace and powerful 2.1.1 Influences material known to him.”[21] This combined with his con- temporary’s idea of "" allow us to Later scholastic thinkers would maintain that in his see how Thales could hold that water could be divine and choice of water Thales was influenced by Babylonian or creative. Chaldean religion, that held that a god had begun creation by acting upon the pre-existing water. Abraham Feldman points to the lasting association of the Feldman holds this does not stand up under closer exam- that “all whatness is wetness” with Thales himself, - ination. In Babylonian religion the water is lifeless and ing out that Diogenes Laertius speaks of a poem, prob- sterile until a god acts upon it, but for Thales water itself ably a satire, where Thales is snatched to heaven by the was divine and creative. He maintained that “All things sun, “Perhaps it was an elaborate paronomasia based on [21] are full of gods”, and to understand the nature of things the fact that thal was the Phoenician word for dew.” was to discover the secrets of the , and through this open the possibility that one could be greater than the grandest Olympian.[21] 2.2 Beliefs in divinity Feldman points out that while other thinkers recognized the wetness of the world “none of them was inspired to Thales applied his method to objects that changed to be- conclude that everything was ultimately aquatic.”[21] He come other objects, such as water into earth (or so he further points out that Thales was “a wealthy citizen of thought). But what about the changing itself? Thales did the fabulously rich Oriental port of Miletus...a dealer in address the topic, approaching it through lodestone and the staples of antiquity, wine and oil...He certainly han- amber, which, when electrified by rubbing together, also dled the shell-fish of the Phoenicians that secreted the attracts. It is noteworthy that the first particle known to dye of imperial purple.”[21] Feldman recalls the stories of carry , the electron, is named for the Greek Thales measuring the distance of boats in the harbor, cre- word for amber, ἤλεκτρον (ēlektron). ating mechanical improvements for ship navigation, giv- How was the power to move other things without the ing an explanation for the flooding of the (vital to movers changing to be explained? Thales saw a common- Egyptian agriculture and Greek trade), and changing the ality with the powers of living things to act. The lodestone course of the river Halys so an army could ford it. Rather and the amber must be alive, and if that were so, there than seeing water as a barrier Thales contemplated the could be no difference between the living and the dead. Ionian yearly religious gathering for athletic ritual (held When asked why he didn’t die if there was no difference, 2.2 Beliefs in divinity 5

he replied “because there is no difference.” such as Colin R. Fletcher, point out that there could Aristotle defined the as the principle of life, that have been a predecessor to Thales who would've been which imbues the matter and makes it live, giving it the named in Eudemus’ lost book of Geometry it is admitted that without the work “the question becomes animation, or power to act. The idea did not originate [25] with him, as the Greeks in general believed in the dis- mere speculation.” Fletcher holds that as there is no tinction between mind and matter, which was ultimately viable predecessor to the title of first Greek mathemati- to lead to a distinction not only between body and soul cian, the only question is whether Thales qualifies as a but also between matter and . practitioner in that field; he holds that “Thales had at his command the techniques of observation, experimenta- If things were alive, they must have . This belief tion, superposition and deduction…he has proved him- was no innovation, as the ordinary ancient populations of self mathematician.”[25] the Mediterranean did believe that natural actions were caused by divinities. Accordingly, the sources say that The evidence for the primacy of Thales comes to us Thales believed that “all things were full of gods.”[22] In from a book by who wrote a thousand years after their zeal to make him the first in everything some said Thales but is believed to have had a copy of Eudemus’ book. Proclus wrote “Thales was the first to go to Egypt he was the first to hold the belief, which must have been [25] widely known to be false. and bring back to Greece this study.” He goes on to tell us that in addition to applying the knowledge he gained However, Thales was looking for something more gen- in Egypt “He himself discovered many and eral, a universal substance of mind. That also was in disclosed the underlying principles of many others to his the polytheism of the times. was the very person- successors, in some case his method being more general, ification of supreme mind, dominating all the subordi- in others more empirical.”[25] nate manifestations. From Thales on, however, philoso- Other quotes from Proclus list more of Thales’ mathemat- phers had a tendency to depersonify or objectify mind, as though it were the substance of animation per se and not ical achievements: actually a god like the other gods. The end result was a “They say that Thales was the first to demonstrate that total removal of mind from substance, opening the door the is bisected by the , the cause of the to a non-divine principle of action. being the unimpeded passage of the straight line [25] Classical thought, however, had proceeded only a little through the centre.” way along that path. Instead of referring to the person, "[Thales] is said to have been the first to have known and Zeus, they talked about the great mind: to have enunciated [the theorem] that the at the base of any isosceles are equal, though in the “Thales”, says ,[23] “assures that water is more archaic manner he described the equal angles as the principle of all things; and that God is that similar.”[25] Mind which shaped and created all things from “This theorem, that when two straight lines cut one an- water.” other, the vertical and opposite angles are equal, was first discovered, as Eudemus says, by Thales, though the sci- The universal mind appears as a Roman belief in entific demonstration was improved by the of Ele- as well: ments.”[25] “Eudemus in his attributes this the- “In the beginning, SPIRIT within (spiritus intus) orem [the equality of having two angles and one strengthens Heaven and Earth, side equal] to Thales. For he says that the method by which Thales showed how to find the distance of ships at The watery fields, and the lucid of Luna, sea necessarily involves this method.”[25] and then -- "Pamphila says that, having learnt geometry from the , he [Thales] was the first to inscribe in a circle a Titan ; and mind (mens) infused through right-angled triangle, whereupon he sacrificed an ox.”[25] the limbs In addition to Proclus, Hieronymus of also cites Agitates the whole , and mixes itself with [24] Thales as the first Greek mathematician. Hieronymus GREAT MATTER (magno corpore)" held that Thales was able to measure the height of the pyramids by a successful application of geometry (after 2.2.1 Reputation gathering by using his staff and comparing its shadow to those cast by the pyramids). We receive variations of Thales (who died around 30 years before the time of Hieronymus’ story through Diogenes Laertius, Pliny the [25] and 300 years before , Eudoxus of Elder, and Plutarch. Due to the variations among tes- Cnidus, and ) is often hailed as “the timonies, such as the “story of the sacrifice of an ox on first Greek mathematician”.[25] While some , the occasion of the discovery that the on a diam- 6 2 THEORIES

eter of a circle is a right angle” in the version told by Diogenes Laertius being accredited to Pythagoras rather than Thales, some historians (such as D. R. Dicks) ques- tion whether such anecdotes have any historical worth whatsoever.[12]

2.2.2 Practice and theory

Thales was known for his innovative use of geometry. His understanding was theoretical as well as practical. For example, he said:

Megiston topos: hapanta gar chorei (Μέγιστον τόπος· άπαντα γαρ χωρεί) ” is the greatest thing, as it contains all things”

Topos is in Newtonian-style space, since the verb, chorei, DE AE AD has the connotation of yielding before things, or spreading Thales’ Theorem: BC = AC = AB out to make room for them, which is . Within this extension, things have a position. Points, lines, planes to define is a matter of opinion. More and solids related by distances and angles follow from this practically Thales used the same method to measure the presumption. distances of ships at sea, said Eudemus as reported by Thales understood similar triangles and right triangles, Proclus (“in Euclidem”). According to Kirk & Raven and what is more, used that knowledge in practical ways. (reference cited below), all you need for this feat is three The story is told in DL (loc. cit.) that he measured the straight sticks pinned at one end and knowledge of your height of the pyramids by their shadows at the altitude. One stick goes vertically into the ground. A sec- when his own shadow was equal to his height. A right tri- ond is made level. With the third you sight the ship and angle with two equal legs is a 45- , all calculate the seked from the height of the stick and its of which are similar. The length of the ’s shadow distance from the point of insertion to the line of sight. measured from the center of the pyramid at that moment The seked is a measure of the angle. Knowledge of two must have been equal to its height. angles (the seked and a right angle) and an enclosed leg This story indicates that he was familiar with the Egyptian (the altitude) allows you to determine by similar triangles seked, or seqed - the of the run to the rise of a slope the second leg, which is the distance. Thales probably had (cotangent). The seked is at the base of problems 56, 57, his own equipment rigged and recorded his own sekeds, 58, 59 and 60 of the Rhind papyrus - an ancient Egyptian but that is only a guess. mathematics document. Thales’ Theorem is stated in another article. (Actually In present day trigonometry, cotangents require the same there are two called Theorem of Thales, one units for run and rise (base and ), but the having to do with a triangle inscribed in a circle and papyrus uses cubits for rise and palms for run, resulting having the circle’s diameter as one leg, the other theo- in different (but still characteristic) . Since there rem being also called the .) In addition were 7 palms in a cubit, the seked was 7 times the cotan- Eudemus attributed to him the discovery that a circle is gent. bisected by its diameter, that the base angles of an isosce- To use an example often quoted in modern reference les triangle are equal and that vertical angles are equal. [26] works, suppose the base of a pyramid is 140 cubits and According to a historical Note, when Thales visited the angle of rise 5.25 seked. The Egyptians expressed Egypt, he observed that whenever the Egyptians drew two their fractions as the sum of fractions, but the intersecting lines, they would measure the vertical angles are sufficient for the example. What is the rise in cubits? to make sure that they were equal. Thales concluded that The run is 70 cubits, 490 palms. X, the rise, is 490 di- one could prove that all vertical angles are equal if one 1 accepted some general notions such as: all straight angles vided by 5.25 or 93 ⁄3 cubits. These figures sufficed for the Egyptians and Thales. We would go on to calculate are equal, equals added to equals are equal, and equals 1 subtracted from equals are equal. It would be hard to the cotangent as 70 divided by 93 ⁄3 to get 3/4 or .75 and looking that up in a table of cotangents find that the angle imagine civilization without these theorems. of rise is a few minutes over 53 degrees. Whether the ability to use the seked, which preceded Influences Due to the scarcity of sources concerning Thales by about 1000 years, means that he was the first Thales and the diversity among the ones we possess, there 2.2 Beliefs in divinity 7

is a scholarly debate over possible influences on Thales only ancient historian that claims Thales visited Babylo- and the Greek that came after him. nia. Historian Roger L. Cooke points out that Proclus does not Herodotus wrote that the Greeks learnt the practice of make any mention of Mesopotamian influence on Thales dividing the day into 12 parts, about the polos, and the or Greek geometry, but “is shown clearly in Greek as- from the Babylonians. (The exact meaning of tronomy, in the use of system of measur- his use of the word polos is unknown, current theories in- ing angles and in ’s explicit use of Mesopotamian clude: “the heavenly dome”, “the tip of the axis of the astronomical observations.”[27] Cooke notes that it may celestial ”, or a spherical concave .) Yet possibly also appear in the second book of Euclid’s El- even Herodotus’ claims on Babylonian influence are con- ements, “which contains geometric constructions equiva- tested by some modern historians, such as L. Zhmud, who lent to certain algebraic relations that are frequently en- points out that the division of the day into twelve parts countered in the tablets.” Cooke notes “This (and by analogy the year) was known to the Egyptians al- relation however, is controversial.”[27] ready in the second millennium, the gnomon was known Historian B.L. Van der Waerden is among those advo- to both Egyptians and Babylonians, and the idea of the “heavenly sphere” was not used outside of Greece at this cating the idea of Mesopotamian influence, writing “It [28] follows that we have to abandon the traditional belief time. that the oldest Greek mathematicians discovered geome- Less controversial than the position that Thales learnt try entirely by themselves…a belief that was tenable only is the claim he was influenced as long as was known about Babylonian mathe- by Egyptians. Pointedly historian S. N. Bychkov holds matics. This in no way diminishes the stature of Thales; that the idea that the base angles of an isosceles trian- on the contrary, his receives only now the honour gle are equal likely came from Egypt. This is because, that is due to it, the honour of having developed a logical when building a roof for a home - having a cross sec- structure for geometry, of having introduced proof into tion be exactly an isosceles triangle isn't crucial (as it’s geometry.”[25] the ridge of the roof that must fit precisely), in contrast a Some historians, such as D. R. Dicks takes issue with the symmetric pyramid cannot have errors in the base angles of the faces or they will not fit together tightly.[27] idea that we can determine from the questionable sources we have, just how influenced Thales was by Babylonian Historian D.R. Dicks agrees that compared to the Greeks in the era of Thales, there was a more advanced state of sources. He points out that while Thales is held to have been able to calculate an eclipse using a cycle called the mathematics among the Babylonians and especially the “Saros” held to have been “borrowed from the Babylo- Egyptians - “both cultures knew the correct formulae for nians”, “The Babylonians, however, did not use cycles determining the and of simple geometri- to predict solar , but computed them from ob- cal figures such as triangles, rectangles, trapezoids, etc.; servations of the of the made shortly be- the Egyptians could also calculate correctly the of fore the expected syzygy.”[12] Dicks cites historian O. the frustum of a pyramid with a square base (the Baby- Neugebauer who relates that “No Babylonian theory for lonians used an incorrect formula for this), and used a formula for the of a circle...which gives a value for π predicting solar eclipse existed at 600 B.C., as one can [12] see from the very unsatisfactory situation 400 year later; of 3.1605--a good approximation.” Dicks also agrees nor did the Babylonians ever develop any theory which that this would have had an effect on Thales (whom the took the influence of geographical latitude into account.” most ancient sources agree was interested in math and as- Dicks examines the cycle referred to as 'Saros’ - which tronomy) but he holds that tales of Thales’ travels in these Thales is held to have used and which is believed to stem lands are pure . from the Babylonians. He points out that Ptolemy makes The ancient civilization and massive monuments of Egypt use of this and another cycle in his book Mathemati- had “a profound and ineradicable impression on the cal Syntaxis but attributes it to Greek earlier Greeks”. They attributed to Egyptians “an immemorial than and not to Babylonians.[12] Dicks notes knowledge of certain subjects” (including geometry) and Herodotus does relate that Thales made use of a cycle would claim Egyptian origin for some of their own ideas to predict the eclipse, but maintains that “if so, the ful- to try and lend them “a respectable antiquity” (such as the fillment of the 'prediction' was a stroke of pure luck not “Hermetic” of the Alexandrian period).[12] science”.[12] He goes further joining with other historians Dicks holds that since Thales was a prominent figure in (F. Martini, J.L. E. Dreyer, O. Neugebauer) in rejecting [12] Greek history by the time of Eudemus but “nothing cer- the historicity of the eclipse story altogether. Dicks tain was known except that he lived in Miletus”.[12] A links the story of Thales discovering the cause for a solar tradition developed that as “Milesians were in a position eclipse with Herodotus’ claim that Thales discovered the to be able to travel widely” Thales must have gone to cycle of the sun with relation to the , and con- Egypt.[12] As Herodotus says Egypt was the birthplace of cludes “he could not possibly have possessed this knowl- geometry he must have learnt that while there. Since he edge which neither the Egyptians nor the Babylonians nor had to have been there, surely one of the theories on Nile his immediate successors possessed.”[12] is the 8 3 INTERPRETATIONS

Flooding laid out by Herodotus must have come from 3.1 Theory Thales. Likewise as he must have been in Egypt he had to have done something with the Pyramids - thus the tale The most natural epithets of Thales are "materialist" and of measuring them. Similar apocryphal stories exist of "naturalist", which are based on and physis. The Pythagoras and traveling to Egypt with no corrob- Catholic notes that Aristotle called him a orating evidence. physiologist, with the meaning “student of nature.”[30] On the other hand, he would have qualified as an early As the Egyptian and Babylonian geometry at the time was , as did Aristotle. They studied corpora, “bod- “essentially arithmetical”, they used actual numbers and ies”, the medieval descendants of substances. “the procedure is then described with explicit instruc- tions as to what to do with these numbers” there was Most agree that Thales’ stamp on thought is the unity of no mention of how the rules of procedure were made, substance, hence Bertrand Russell:[31] and nothing toward a logically arranged corpus of gen- eralized geometrical knowledge with analytical 'proofs’ “The view that all matter is one is quite a rep- such as we find in the words of Euclid, , utable scientific hypothesis.” and Apollonius.”[12] So even had Thales traveled there he "...But it is still a handsome feat to have dis- could not have learnt anything about the theorems he is covered that a substance remains the same in held to have picked up there (especially because there is different states of aggregation.” no evidence that any Greeks of this age could use Egyp- tian hieroglyphics).[12] Russell was only reflecting an established tradition; for example: Nietzsche, in his Philosophy in the Tragic Age Likewise until around the second century BC and the time of the Greeks, wrote:[32] of Hipparchus (c. 194-120 BC) the Babylonian general division of the circle into 360 degrees and their sexa- [12] “Greek philosophy seems to begin with an ab- gesimal system was unknown. Herodotus says almost surd , with the that water is nothing about Babylonian literature and science, and very the primal origin and the womb of all things. Is little about their history. Some historians, like P. Schn- it really necessary for us to take serious notice abel, hold that the Greeks only learned more about Baby- of this proposition? It is, and for three . lonian culture from , a Babylonian priest who is First, because it tells us something about the said to have set up a school in around 270 BC (but to primal origin of all things; second, because it what extent this had in the field of geometry is contested). does so in language devoid of image or fable, Dicks points out that the primitive state of Greek math- and finally, because contained in it, if only em- ematics and astronomical ideas exhibited by the pecu- bryonically, is the thought, 'all things are one.'" liar notions of Thales’ successors (such as , Anaximenes, , and Heraclitus), which histo- This sort of , however, should not be confused rian J. L. Heiberg calls “a mixture of brilliant intuition with deterministic materialism. Thales was only trying to and childlike analogies”,[29] argues against the assertions explain the unity observed in the free play of the qualities. from in late antiquity that Thales discovered and The arrival of uncertainty in the modern world made pos- taught advanced concepts in these fields. sible a return to Thales; for example, John Elof Boodin writes (“God and Creation”):

“We cannot read the universe from the past...” 3 Interpretations Boodin defines an “emergent” materialism, in which the In the long sojourn of philosophy there has existed hardly objects of sense emerge uncertainly from the substrate. a philosopher or historian of philosophy who did not men- Thales is the innovator of this sort of materialism. tion Thales and try to characterize him in some way. He is generally recognized as having brought something new to 3.2 Rise of theoretical inquiry thought. Mathematics, and already existed. Thales added something to these differ- In the West, Thales represents a new kind of inquiring ent collections of knowledge to produce a universality, community as well. [33] attempts to cap- which, as far as writing tells us, was not in tradition be- ture the new movement as follows. Philosophical man is a fore, but resulted in a new field. “new cultural configuration” based in stepping back from Ever since, interested persons have been asking what that “pregiven tradition” and taking up a rational “inquiry into new something is. Answers fall into (at least) two cate- what is true in itself;" that is, an ideal of . It begins gories, the theory and the method. Once an answer has with isolated individuals such as Thales, but they are sup- been arrived at, the next logical step is to ask how Thales ported and cooperated with as time goes on. Finally the compares to other philosophers, which leads to his clas- ideal transforms the norms of society, leaping across na- sification (rightly or wrongly). tional borders. 9

3.3 Classification Thales advised him to travel to Egypt to further his - sophical and mathematical studies. The term "Pre-Socratic" derives ultimately from the Many philosophers followed Thales’ lead in searching for philosopher Aristotle, who distinguished the early explanations in nature rather than in the supernatural; oth- philosophers as concerning themselves with substance. ers returned to supernatural explanations, but couched Diogenes Laertius on the other hand took a strictly ge- them in the language of philosophy rather than of myth ographic and ethnic approach. Philosophers were either or of religion. Ionian or Italian. He used “Ionian” in a broader sense, in- Looking specifically at Thales’ influence during the pre- cluding also the Athenian academics, who were not Pre- Socratic era, it is clear that he stood out as one of the Socratics. From a philosophic point of view, any group- first thinkers who thought more in the way of than ing at all would have been just as effective. There is mythos. The difference between these two more profound no basis for an Ionian or Italian unity. Some scholars, ways of seeing the world is that mythos is concentrated however, concede to Diogenes’ scheme as far as referring around the stories of holy origin, while logos is concen- to an “Ionian” school. There was no such school in any trated around the argumentation. When the mythical man sense. wants to explain the world the way he sees it, he explains The most popular approach refers to a , it based on gods and powers. Mythical thought does not which is more justifiable socially and philosophically. differentiate between things and persons and furthermore They sought for the substance of phenomena and may it does not differentiate between nature and culture. The have studied with each other. Some ancient writers qual- way a logos thinker would present a world view is radically ify them as Milesioi, “of Miletus.” different from the way of the mythical thinker. In its con- form, logos is a way of thinking not only about indi- vidualism, but also the abstract. Furthermore, it focuses 4 Influence on others on sensible and continuous argumentation. This lays the foundation of philosophy and its way of explaining the world in terms of abstract argumentation, and not in the way of gods and mythical stories.

5 Reliability of sources

Thales (), from “The Progress of Railroad- ing” (1908), main facade of Union Station (Washington, DC)

Thales had a profound influence on other Greek thinkers and therefore on Western history. Some believe Anaximander was a pupil of Thales. Early sources re- Thales, Nuremberg Chronicle. port that one of Anaximander’s more famous pupils, Pythagoras, visited Thales as a young man, and that Because of Thales’ elevated status in Greek culture an 10 5 RELIABILITY OF SOURCES

intense interest and admiration followed his reputation. ple of the intelligent man who possesses some technical Due to this following, the oral stories about his life were 'know how'...the later doxographers [such as open to amplification and historical fabrication, even be- in the latter half of the fourth century BC] foist on to him fore they were written down generations later. Most mod- any number of discoveries and achievements, in order to ern dissension comes from trying to interpret what we build him up as a figure of superhuman wisdom.”[12] know, in particular, distinguishing legend from fact. Dicks points out a further problem arises in the surviv- Historian D.R. Dicks and other historians divide the an- ing information on Thales, for rather than using ancient cient sources about Thales into those before 320 BC sources closer to the era of Thales, the authors in later and those after that year (some such as Proclus writ- antiquity (“epitomators, excerptors, and compilers”[12]) ing in the 5th century C.E. and Simplicius of actually “preferred to use one or more intermediaries, in the 6th century C.E. writing nearly a millennium af- so that what we actually read in them comes to us not ter his era).[12] The first category includes Herodotus, even at second, but at third or fourth or fifth hand. ...Ob- Plato, Aristotle, , and among viously this use of intermediate sources, copied and re- others. The second category includes , Aetius, copied from century to century, with each writer adding , Plutarch, Josephus, , Diogenes additional pieces of information of greater or less plausi- Laërtius, , , Clement of bility from his own knowledge, provided a fertile field for , , and among oth- errors in transmission, wrong ascriptions, and fictitious ers. attributions”.[12] Dicks points out that “certain doctrines The earliest sources on Thales (living before 320 BC) that later commentators invented for Thales...were then are often the same for the other Milesian philosophers accepted into the biographical tradition” being copied by (Anaximander, and Anaximenes). These sources were subsequent writers who were then cited by those coming either roughly contemporaneous (such as Herodotus) or after them “and thus, because they may be repeated by different authors relying on different sources, may pro- lived within a few hundred years of his passing. More- [12] over, they were writing from an oral tradition that was duce an illusory impression of genuineness.” widespread and well known in the Greece of their day. Doubts even exist when considering the philosophical - sitions held to originate in Thales “in reality these stem The latter sources on Thales are several “ascriptions of commentators and compilers who lived anything from directly from Aristotle’s own interpretations which then [12] became incorporated in the doxographical tradition as er- 700 to 1,000 years after his death” which include [12] “anecdotes of varying degrees of plausibility”[12] and in roneous ascriptions to Thales”. (The same treatment the opinion of some historians (such as D. R. Dicks) of was given by Aristotle to .) “no historical worth whatsoever”.[12] Dicks points out that Most philosophic analyses of the philosophy of Thales there is no agreement “among the 'authorities’ even on come from Aristotle, a professional philosopher, tutor of the most fundamental facts of his life--e.g. whether he , who wrote 200 years after Thales’ was a Milesian or a Phoenician, whether he left any writ- death. Aristotle, judging from his surviving , does ings or not, whether he was married or single-much less not seem to have access to any works by Thales, although on the actual ideas and achievements with which he is he probably had access to works of other authors about credited.”[12] Thales, such as Herodotus, Hecataeus, Plato etc., as well Contrasting the work of the more ancient writers with as others whose work is now extinct. It was Aristotle’s those of the later, Dicks points out that in the works of express goal to present Thales’ work not because it was significant in itself, but as a prelude to his own work the early writers Thales and the other men who would [34] be hailed as “the ” had a different in . Geoffrey Kirk and , reputation than that which would be assigned to them by English compilers of the fragments of the Pre-Socratics, later authors. Closer to their own era, Thales, Solon, assert that Aristotle’s “judgments are often distorted by of Priene, Pittacus of and others were hailed his view of earlier philosophy as a stumbling progress to- ward the truth that Aristotle himself revealed in his phys- as “essentially practical men who played leading roles in [35] the affairs of their respective states, and were far better ical doctrines.” There was also an extensive oral tradi- tion. Both the oral and the written were commonly read known to the earlier Greeks as lawgivers and statesmen than as profound thinkers and philosophers.”[12] For ex- or known by all educated men in the region. ample, Plato praises him (coupled with ) for Aristotle’s philosophy had a distinct stamp: it professed being the originator of the potter’s wheel and the anchor. the theory of matter and form, which modern scholas- Only in the writings of the second group of writers (work- tics have dubbed . Though once very ing after 320 BC) do “we obtain the picture of Thales as widespread, it was not generally adopted by rationalist the pioneer in Greek scientific thinking, particularly in re- and modern science, as it mainly is useful in metaphysical gard to mathematics and astronomy which he is supposed analyses, but does not lend itself to the detail that is of in- to have learnt about in and Egypt.”[12] Rather terest to modern science. It is not clear that the theory of than “the earlier tradition [where] he is a favourite exam- matter and form existed as early as Thales, and if it did, 11

whether Thales espoused it. [3] Singer, C. (2008). A Short to the 19th century. Streeter Press. p. 35. While some historians, like B. Snell, maintain that Aristo- tle was relying on a pre-Platonic written record by [4] Needham, C. W. (1978). Cerebral Logic: Solving the rather than oral tradition, this is a controversial position. Problem of Mind and Brain. Loose Leaf. p. 75. ISBN Representing the scholarly consensus Dicks states that 0-398-03754-X. “the tradition about him even as early as the fifth cen- [5] (Boyer 1991, “Ionia and the Pythagoreans” p. 43) tury B.C., was evidently based entirely on hearsay....It would seem that already by Aristotle’s time the early - [6] Herodotus, 1.74.2, and A. D. Godley’s footnote 1; Pliny, nians were largely names only to which popular tradition 2.9 (12) and Bostock’s footnote 2. attached various ideas or achievements with greater or less plausibility”.[12] He points out that works confirmed [7] Plutarch (1952). “Solon”. In Robert Maynard Hutchins. to have existed in the sixth century BC by Anaximander Lives. of the 14. Chicago: William Benton. p. 66. and Xenophanes had already disappeared by the fourth century BC, so the chances of Pre-Socratic material sur- [8] Diogenes Laërtius, 1.43, 44. viving to the age of Aristotle is almost nil (even less likely for Aristotle’s pupils Theophrastus and Eudemus and less [9] Aristotle, Politics 1259a likely still for those following after them). [10] Book 1 The main secondary source concerning the details of [11] 1.25 Thales’ life and career is Diogenes Laertius,"Lives of Eminent Philosophers".[36] This is primarily a biograph- [12] D. R. Dicks (November 1959). “Thales”. ical work, as the name indicates. Compared to Aristotle, The Classical Quarterly 9 (2): 294–309. Diogenes is not much of a philosopher. He is the one doi:10.1017/S0009838800041586. who, in the Prologue to that work, is responsible for the [13] 1.22 division of the early philosophers into “Ionian” and “Ital- ian”, but he places the Academics in the Ionian school and [14] Farrington, B., 1944 Greek Science. Pelican otherwise evidences considerable disarray and contradic- tion, especially in the long section on forerunners of the [15] English physics comes from it, but the latter is a Greek “Ionian School”. Diogenes quotes two letters attributed loan. In addition the quite ancient native English word be to Thales, but Diogenes wrote some eight centuries after comes from the same Indo-European root. Thales’ death and that his sources often contained “unre- [16] The initial g of the archaic gives the root away as liable or even fabricated information”,[37] hence the con- *genə-, “beget.” cern for separating fact from legend in accounts of Thales. [17] Metaphysics 983b6 It is due to this use of hearsay and a lack of citing original sources that leads some historians, like Dicks and Werner [18] 983 b6 8-11 Jaeger, to look at the late origin of the traditional picture [19] Quaes. Hom. 22, not the same as Heraclitus of of Pre-Socratic philosophy and view the whole idea as a construct from a later age, “the whole picture that has [20] Work cited, paragraph 27. come down to us of the history of early philosophy was fashioned during the two or three generations from Plato [21] Abraham Feldman (Oct 1945). “Thoughts on Thales”. to the immediate pupils of Aristotle”.[38] The Classical Journal 41 (1): 4–6. [22] Aristotle, De Anima, 411a7. For other ancient sources see the discussion in Kirk and Raven, The Presocratic Philoso- 6 See also phers, 93-7. [23] , i.,10 • [24] Virgil:",” vi., 724-727. • Material [25] Colin R. Fletcher (December 1982). The Mathematical • The Astrologer who Fell into a Well Gazette (The Mathematical Association) 66 (438): 267. [26] William G. Shute, William W. Shirk, George F. Porter, and , American Book Company 7 Notes (1960) pp. 25-27 [27] Roger L. Cooke (2005). The : A [1] Aristotle, Metaphysics Alpha, 983b18. Brief Course. John Wiley & Sons, Inc.

[2] Russell, Bertrand (1945). The History of Western Philos- [28] Leonid Zhmud (2006). The Origin of the History of Sci- ophy. New York: Simon and Schuster. ence in . Die Deutsche Bibliothek. 12 10 EXTERNAL LINKS

[29] J. L. Gesch (1925). D. Math. Und Naturwiss. im Altertum. 9 Further reading Munich. p. 50. • Couprie, Dirk L. (2011). Heaven and Earth in An- [30] Turner, Catholic Encyclopedia. cient Greek : from Thales to . Springer. ISBN 9781441981158. [31] Wisdom of the West • Luchte, James (2011). Early Greek Thought: Before [32] § 3 the Dawn. London: Bloomsbury Publishing. ISBN 978-0567353313. [33] The Vienna Lecture • O'Grady, Patricia F. (2002). : [34] See Aristotle, Metaphysics Alpha, 983b 1-27. The Beginnings of Western Science and Philosophy. 58. Ashgate. ISBN [35] Kirk and Raven, The Presocratic Philosophers, Second 9780754605331. Edition ( University Press, 1983) 3. • Mazzeo, Pietro (2010). Talete, il primo filosofo. [36] Translation of his biography on Thales: Thales, clas- Bari: Editrice Tipografica. sicpersuasion site; original Greek text, under ΘΑΛΗΣ, the Library of Ancient Texts Online site.

[37] See McKirahan, Richard D., Jr. (1994). Philosophy Be- 10 External links fore . Indianapolis: Hackett. p. 5. ISBN 0- 87220-176-7. • Media related to Thales at Wikimedia Commons [38] Werner Jaeger (1948). Aristotle (2nd ed.). p. 454. • Quotations related to Thales at Wikiquote

• Works written by or about Thales at Wikisource 8 References • Thales of Miletus from The Internet Encyclopedia of Philosophy • Burnet, John (1957) [1892]. Early Greek Philoso- • Thales of Miletus from the MacTutor History of phy. The Library. Third Edition Mathematics archive

• Diogenes Laërtius, Life of Thales, translated by • Livius, Thales of Miletus by Jona Lendering (1925). • Thales • Herodotus; , A. D. Godley (translator), • Thales’ Theorem - Math Open Reference (with in- Cambridge: Press, 1920; ISBN teractive animation) 0-674-99133-8. Online version at • Thales biography by Charlene Douglass (with exten- • Hans Joachim Störig: Kleine Weltgeschichte der sive bibliography) Philosophie. Fischer, Frankfurt/M. 2004, ISBN 3- • 596-50832-0. Thales’ eclipse of sun • Thales Fragments • Kirk, G.S.; Raven, J.E. (1957). The Presocratic Philosophers. Cambridge: University Press.

• G. E. R. Lloyd. Early Greek Science: Thales to Aris- totle.

• Nahm, Milton C. (1962) [1934]. Selections from Early Greek Philosophy. Appleton-Century-Crofts.

• Pliny the Elder; The (eds. John Bo- stock, M.D., F.R.S. H.T. Riley, Esq., B.A.) London. Taylor and Francis. (1855). Online version at the Perseus Digital Library.

• Turner, William (1910). “The Catholic Encyclope- Volume 8”. Ionian School of Philosophy. New York: Robert Appleton. 13

11 Text and image sources, contributors, and licenses

11.1 Text

• Thales Source: http://en.wikipedia.org/wiki/Thales?oldid=631381051 Contributors: MichaelTinkler, Brion VIBBER, Mav, Bryan Derk- sen, Koyaanis Qatsi, Andre Engels, XJaM, Matusz, Olivier, Lir, Michael Hardy, Llywrch, Isomorphic, Nixdorf, Ixfd64, Dcljr, Big iron, Jeandré du Toit, Adam Conover, Koxinga, Charles Matthews, Adam Bishop, Radgeek, Tpbradbury, Thue, Secretlondon, Shafei, Lumos3, Mrdice, Naturyl, Dedoleo, Chuunen Baka, Robbot, 1984, Jaredwf, PBS, Lowellian, Rursus, Diderot, Andrew Levine, Mark Krueger, Wikibot, Gat, Dave6, Giftlite, DocWatson42, Inter, Fleminra, Mrjake, Noname, Joseph Dwayne, ChicXulub, Chowbok, Clockwork- Lunch, MisfitToys, Joseph Myers, Jossi, JimWae, Icairns, Gscshoyru, HunterX, Robin Hood, Ukexpat, Cwoyte, Lucidish, Simonides, DanielCD, An Siarach, Noisy, Rich Farmbrough, FranksValli, Florian Blaschke, Mani1, Paul August, Bender235, ESkog, Silentlight, CanisRufus, Chairboy, Shanes, 96T, Bobo192, Smalljim, Cje, BrokenSegue, Nicke Lilltroll, Nk, Knucmo2, Jumbuck, Danski14, Alan- sohn, JYolkowski, SnowFire, Eric Kvaalen, Seans Potato Business, Velella, Leoadec, Gpvos, Sciurinæ, Kazvorpal, Dennis Bratland, Oleg Alexandrov, FeanorStar7, Starwiz, Miaow Miaow, WadeSimMiser, Chochopk, Kristaga, Bkwillwm, Wikiklrsc, Hotshot977, Bluemoose, Fryd1e, Pfalstad, Marudubshinki, Dysepsion, Magister Mathematicae, BD2412, Melesse, Mendaliv, Rjwilmsi, Trlovejoy, Infosocialist, Kalogeropoulos, Bubba73, Reinis, Sango123, Yamamoto Ichiro, FlaBot, RexNL, Gurch, Choess, GreyCat, Piniricc65, Reediewes, Scimi- tar, Chobot, Jaraalbe, Mhking, Korg, VolatileChemical, Gwernol, YurikBot, Wavelength, RobotE, Sceptre, Jimp, Epolk, Stephenb, Gaius Cornelius, Wimt, Bullzeye, Ugur Basak, Odysses, Anomie, Aftermath, Grafen, Nick, Aldux, Misza13, Yiuchung, Elizabeyth, Roy Brum- back, .marc., Botteville, Wknight94, Igiffin, Deville, Sshadow, Dspradau, Tevildo, JoanneB, Hyst, Whobot, Allens, Kungfuadam, GrinBot, Ryūkotsusei, Luk, CHITRANI, IslandHopper973, Jsnx, SmackBot, Selfworm, Moeron, Lestrade, Incnis Mrsi, Levi allemany, Zerida, Ki- mon, KocjoBot, Jagged 85, Thunderboltz, RobotJcb, Gilliam, Chris the speller, Bluebot, Master of Puppets, Martinmuse, MalafayaBot, DHN-bot, Hongooi, John Reaves, Can't sleep, clown will eat me, Sumahoy, Writtenright, OrphanBot, Addshore, Essent, Stevenmitchell, Fuhghettaboutit, EPM, Valenciano, Limexx35, Shadow1, Dreadstar, KRBN, LoveMonkey, Jaellee, DMacks, Gatoatigrado, Rickmorcom, Thejerm, Tdw1203, Nareek, Khazar, Hemmingsen, Peterlewis, IronGargoyle, The Man in Question, Munita Prasad, Salzman, Op- takeover, Mets501, Nwwaew, Funnybunny, Novangelis, MTSbot, Peyre, Hu12, Mig77, Iridescent, Lottamiata, Igoldste, Happy-melon, Az1568, Dkastner, Tawkerbot2, Chetvorno, CmdrObot, JohnCD, Pfhenshaw, Moreschi, Hemlock Martinis, Shanoman, Cydebot, Ntsimp, , Dougweller, Codetiger, DumbBOT, Chrislk02, Thesecondworldwar.net, Thijs!bot, Epbr123, Barticus88, Headbomb, AgentPep- permint, Michael A. White, Johnwrw, Escarbot, Eleuther, AntiVandalBot, Insulanus, John.d.page, Prolog, D. Webb, Wahabijaz, JAnD- bot, Deflective, MER-C, BlindEagle, Acroterion, Pianodwarf, Magioladitis, VoABot II, Italus, Professor marginalia, Waacstats, Animum, EagleFan, DerHexer, Baristarim, Cedricbear, RichMac, MartinBot, Wowaconia, Jim.henderson, Rettetast, R'n'B, CommonsDelinker, Pbroks13, VirtualDelight, Tgeairn, J.delanoy, Mariehuynh, Terrek, Maurice Carbonaro, Nigholith, WFinch, Filippo Argenti, Galanskov, Joannachan, Bot-Schafter, AntiSpamBot, Chiswick Chap, Belovedfreak, NewEnglandYankee, Aervanath, Biglovinb, Cometstyles, Inwind, S, Measure for Measure, VolkovBot, ABF, Historybuff90, Macedonian, Philip Trueman, TXiKiBoT, Omarraii, Dommccas, GcSwRhIc, Qxz, Someguy1221, Anna Lincoln, Ontoraul, Jackfork, LeaveSleaves, BotKung, MDfoo, JesterCountess, Gchambonthales, Why Not A Duck, Alcmaeonid, Logan, Struway, Gaelen S., SieBot, Scarian, Kevmanetti, Beavis5000, Dawn Bard, Caltas, Triwbe, Peter cohen, Peter- bruce01, Flyer22, Momo , Oxymoron83, Harry, Gja34, Alex.muller, Dkderick, Angielaj, Trumpetcase, 3rdAlcove, Xiscobernal, Athe- nean, Atif.t2, ClueBot, The Thing That Should Not Be, XPTO, CounterVandalismBot, Singinglemon, Puchiko, Sustainablefutures2015, No such user, Excirial, Alexbot, Eeekster, Rhododendrites, Patricius , NuclearWarfare, Davitenio, Jotterbot, Basketball110, Ra- zorflame, Thehelpfulone, Catalographer, Aitias, Versus22, DBodor, Cow Taurog, NorthernDrifter, Semitransgenic, Chronicler, Rror, Little Mountain 5, PL290, Jbeans, HarlandQPitt, Kbdankbot, HexaChord, Addbot, Hockeyrockcars, The Sage of Stamford, Some jerk on the Internet, Atethnekos, 15lsoucy, CanadianLinuxUser, Fluffernutter, Tedmund, LaaknorBot, AndersBot, Jsf8204, Greenmangowango, Fall- enAngel7789, Mtpuls1092, rolls, Alcove, First Light, Xenobot, JEN9841, Fushigi-kun, Legobot, Luckas-bot, Yobot, Les boys, THEN WHO WAS PHONE?, Markcob, Johnelwayrules, AnomieBOT, Killiondude, JackieBot, Piano non troppo, Kingpin13, Zxabot, Materialsci- entist, ImperatorExercitus, Citation bot, NATALEE--xD, ArthurBot, Teddyw73, Xqbot, Gilo1969, GrouchoBot, Omnipaedista, Paulasiri2, Nedim Ardoğa, GhalyBot, N419BH, Shadowjams, AlexanderVanLoon, Gummieworm, FreeKnowledgeCreator, GT5162, FrescoBot, Tan- gent747, Paine Ellsworth, Recognizance, Pergamino, Tavernsenses, Elf 1735, A little insignificant, Noqoilpi, Stockback, Winterst, Pinethicket, Edderso, At-par, Calmer , RedBot, Pike84, Pezanos, Tim1357, Greco22, TobeBot, Pollinosisss, Oracleofottawa, Vre- nator, Ashot Gabrielyan, Mccartjt, DARTH SIDIOUS 2, ChanDMan2010, RjwilmsiBot, Jkyriazoglou, EmausBot, ImprovingWiki, - cles31, RA0808, Rarevogel, Mitartep, Princess Lirin, Wikipelli, K6ka, Andrewkim99, Finemann, Tolly4bolly, AleksandrGertsen, DASH- BotAV, Nickbyrd, Gwen-chan, ClueBot NG, Smtchahal, Michaelmas1957, Manubot, Chester Markel, Neoglyph, Jazgirl13, YOPbottle, Widr, Helpful Pixie Bot, Joevandy, Lrocky223, DBigXray, BG19bot, 23x2, Laureos, Martinosacchi, Gabloo, Davidiad, Mark Arsten, Waliddamouny, Glacialfox, Klilidiplomus, This Is M4dn355 300, TheNuszAbides, BattyBot, Liam987, Khazar2, Welshwatch, Vanished user sdij4rtltkjasdk3, Dexbot, Lugia2453, RideLightning, Juc123, Hillbillyholiday, Tentinator, Alphadog3200, RaphaelQS, Sapiente2222, Fredmond4, Kleobulos Jefferson, Abc 123 xyz 456, Ro2am, Monkbot, Sparklesrule, Straight Busta and Anonymous: 656

11.2 Images

• File:Capernaum_roman_olive_press_by_David_Shankbone.jpg Source: http://upload.wikimedia.org/wikipedia/commons/3/3c/ Capernaum_roman_olive_press_by_David_Shankbone.jpg License: CC-BY-SA-3.0 Contributors: Own work Original artist: David Shankbone (attribution required) • File:Folder_Hexagonal_Icon.svg Source: http://upload.wikimedia.org/wikipedia/en/4/48/Folder_Hexagonal_Icon.svg License: ? Con- tributors: ? Original artist: ? • File:Louisstgaudens1.jpg Source: http://upload.wikimedia.org/wikipedia/commons/6/68/Louisstgaudens1.jpg License: CC-BY-3.0 Contributors: Photograph by Dan Vera Original artist: Original uploader was Danvera at en.wikipedia • File:MiletusIonicStoa.jpg Source: http://upload.wikimedia.org/wikipedia/commons/0/04/MiletusIonicStoa.jpg License: Public domain Contributors: Originally from en.wikipedia; description page is/was here. Original artist: Original uploader was Monsieurdl at en.wikipedia • File:Nuremberg_chronicles_f_59r_2.png Source: http://upload.wikimedia.org/wikipedia/commons/1/11/Nuremberg_chronicles_f_ 59r_2.png License: Public domain Contributors: Scan from original book Original artist: Michel Wolgemut, Wilhelm Pleydenwurff • File:People_icon.svg Source: http://upload.wikimedia.org/wikipedia/commons/3/37/People_icon.svg License: CC0 Contributors: Open- Clipart Original artist: OpenClipart 14 11 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

• File:Portal-puzzle.svg Source: http://upload.wikimedia.org/wikipedia/en/f/fd/Portal-puzzle.svg License: ? Contributors: ? Original artist: ? • File:Question_book-new.svg Source: http://upload.wikimedia.org/wikipedia/en/9/99/Question_book-new.svg License: ? Contributors: Created from scratch in Adobe Illustrator. Based on Image:Question book.png created by User:Equazcion Original artist: Tkgd2007 • File:Solar_eclipse_1999_4_NR.jpg Source: http://upload.wikimedia.org/wikipedia/commons/1/1c/Solar_eclipse_1999_4_NR.jpg Li- cense: CC-BY-SA-3.0 Contributors: Own work www.lucnix.be Original artist: Luc Viatour • File:Thales_theorem_1.png Source: http://upload.wikimedia.org/wikipedia/commons/d/d5/Thales_theorem_1.png License: CC-BY- SA-3.0 Contributors: ? Original artist: ?

11.3 Content license

• Creative Commons Attribution-Share Alike 3.0