apocalyptic visions miniscript Philosophy of Mind SS05 University of Osnabrueck Florian Halbritter [[email protected]] http://www-lehre.inf.uos.de/˜fhalbrit July 2, 2005 1 2 Prologue This document represents my attempt for a summary of the lecture. It is a compilation of the lecture slides and some additional information gained from literature and personal considerations. I neither claim this overview to be complete nor flawlessly correct. If you notice any mistakes and/or feel an urge to utter any (constructive) criticism, contact me via email at [email protected] Feel free to distribute this document amongst your friends. Good luck, Florian Halbritter Osnabrueck, July 2, 2005 CONTENTS 3 Contents 1 Introduction 4 2 Theories 5 2.1 Folk Psychology . 5 2.2 Semantic Physicalism . 6 2.3 Identity Theory . 6 2.4 Functionalism . 8 2.5 Computational Theory of Mind . 9 2.6 Emergentism . 10 2.7 Eliminative Materialism . 12 3 Levels of Analysis 13 4 Animals and Beliefs 14 5 Phenomenal Qualities 15 6 Emotions 16 4 1 INTRODUCTION 1 Introduction Methods: • by ourselves (introspection) • by others • by modelling artificial minds Central topics: • characteristic features of the mental • mind-body problem = relation between the mental and the physical • intentionality and phenomenal consciousness • emotions • freedom of will Typical kinds of questions: • metaphysics/ontology: Which entities exist (mental ones?)? What is the real nature of an entity x? How do certain entities relate (mind-body)? Do certain entities possess a causal power? Can we reduce mental entities to physical ones? • epistemology: What is and how can we gain knowledge? What kind of knowledge is accessible to us? Knowledge of our own mind (problem of privileged access) vs. mental states of other people (other minds problem) How can I be sure that other beings experience mental events, too? Can I be even sure about my own ones? • semantics: What is the meaning and reference of the expression e (i.e. of certain mental concepts)? How do we learn this? • methodology: What methods are available to study certain phenomena? Do purely philosophical means suffice or do we have to consider e.g. findings from neuroscience, too? 5 – methodological behaviorism – cognitive/computational approach – neuroscientific approach – introspection 2 Theories 2.1 Folk Psychology Folk Psychology = The basic knowledge people have (or think to have) about the mind. Referred to as the basis of the prediction and explanation of behavior in our everyday lives. Vocabulary: beliefs, desires Advocacy: Jerry Fodor, Aristotle Predictions and explanations are based upon the assumption of rationality and truthfulness! Reasoning done by some kind of practical syllogism1. Where does the knowledge of our mind / other people’s minds come from? • Introspection (Descartes, Wundt, James) introspection = non-inferential access to one’s own mind, first-person mental state ascriptions are incorrigible and infallible • Methodological (Psychological) Behaviorism (Watson, Skinner) Claim: A correct methodology should be concerned with observable and objective measures (i.e. behavior) →it may not refer to mental states + introspection is an scientifically improper approach BUT: meth.beh. does not state that there are no mental states with a privileged access which may be described in out common-sense con- cepts • Logical (Philosophical) Behaviorism / Semantic Physicalism (Ryle, Hempel, Carnap) Claim: Beliefs and desires inhering in an unobservable mind do not exist. These terms actually refer to publicly observable events, i.e. in dispositions to behave in a certain way 1desire + belief = action, compare to the classical/ theoretical syllogism: assump- tion/observation1 + a/o2 = conclusion 6 2 THEORIES →since beliefs and intentions are not internal they cannot be revealed by introspection (cont. in next section) 2.2 Semantic Physicalism Semantic Physicalism = It is possible to define every mental expression in terms of behavioral and physical expressions Advocacy: Ryle, Hempel, Carnap, Wittgenstein Focused on the question, how to analyze and understand the vocabulary we use to talk about mental states. →rules out any kind of dualism or pluralism (’unity of science’) →(Hempel, Carnap:) the meaning of any sentence is captured by observ- able, physical circumstances which verify it (positivist translatability), i.e. anything can be expressed without a loss of content in a physicalist language (translated to and/or defined in terms of) →(Wittgenstein, Ryle:) most philosophical problems are caused by linguis- tic and conceptual confusion and therefore solved by careful analysis Modern physicalism is behavioristic. Consciousness is either a special type of behavior or a disposition to behave in a certain way. Objections to Semantic Physicalism: • infinity of explanation: trying to define mental predicates in a solely physical language is an infinite endeavor • infinity of qualifications: qualifications themselves entail mental concepts and we therefore run into a cycle 2.3 Identity Theory Identity Theory = Reductive Physicalism or Materialism = Every mental property is identical with some physical property. Every mental predicate denotes a physical predicate. Advocacy: Place, Smart, Armstrong, Feigl Preconditions of identification (”A is B”): • the identity somehow follows from the meanings of A and B 2.3 Identity Theory 7 • the statement can philosophically informative only if it is in same way reductive • note that the reference of two things can be the same, whereas their sense is not! (cp. the ’morning star’) Arguments pro identity theory: • Smart: Everything in the world is describable in terms of its physical con- stituents, so why should consciousness be something over and above these? Saying that mental states are correlated to brain processes does not help. • Kim: – decrease of the number of entities →improves ontological sim- plicity – can help conceptual or linguistic simplicity, i.e. while men- talistic vocabulary might be indispensable in practice, it does not describe anything but the facts described by a physical language – decrease of the number of lawlike correlations Arguments contra identity theory: • Putnam: Pain is not a physicochemical brain state but a functional state of a whole organism. Argument: In order to allow identification, a cross-racially shared brain state for pain had to be determined (and even one for all other mental states), which is extremely unlikely. – countered by Local Reduction (Kim): The pain of every species can be reduced to a physical property Pi and similarly for other species • Kripke: Objection in terms of logics in possible worlds. Rigid designators are names that denote the same entities in all these worlds. Propositions are necessarily true, iff they are true in all worlds. Four kinds of truths: – necessary, a priori (e.g. ’all bachelors are unmarried’) – contingent, a posteriori (e.g. ’ten years ago there was no CogSci program in Osnabrueck’) 8 2 THEORIES – necessary, a posteriori (e.g. ’Peter Bieri = Pascal Mecieri’) – contingent, a priori (e.g. ’I am now here’) To make the identity theory true, we require necessary truth. There- fore ’pain’ and ’brain state’ have to be rigid designators. However, we can conceive circumstance under which ’pain’=’brain state’ is not true and these circumstances cannot be explained away as illusions, ergo the identity statement cannot be true. 2.4 Functionalism Functionalism = Mental states are in fact functional states characterized by their causal role (i.e. the relation between inputs and outputs) Advocacy: Block Types of functionalism: • functional analysis (considered with decomposing complex systems into their subcomponents and explaining the working of the whole in terms of the relations amongst these parts) • computation-representation functionalism (mental processes are decomposed to atomic parts, psychological states represent the world in a language of thought, mental processes are computations using those representations) • metaphysical functionalism (theory of the nature of mind, con- cerned with what mental states are and not with how they account for behavior) →mental states are inner causes of behavior characterized by – input clauses – output clauses – interaction clauses • machine functionalism (computer functionalism) typically referring to some kind of Turing machines (i.e. simple automata that relate inputs via a machine table to other states or to outputs) →rules from the transition table can be mapped to Ramsey sentences of the form ∃x1∃x2TSystem(x, x1, x2). These sentences can be used to define the concept of a System and the functional states. • causal-role functionalism 2.5 Computational Theory of Mind 9 • functional states as a causal role or as the bearer of that role? Functionalism stays ontologically neutral (so it does not take a physical- istic side, i.e. it does not say how functional states are realized) Problems for functionalism: • strange realizations (Block): We might have an artificial system behaving just like humans do (e.g. by completely mirroring the human brain). Instead of a computer, this simulation might be run by the whole population of China, too. However, this seems very unrealistic... • how to specify inputs and outputs • intentionality and the problem of understanding (Searle) • qualia – inverted spectrum – absent qualia 2.5 Computational Theory of Mind Intentionality = The power of the mind to be about, to represent or to stand for something Brentano: • intentional phenomena are directed towards something different