Mind, Body and Philosophy Dualism Physicalism Identity Theory of Mind Anomalous Monism Eliminative Materialism Philosophy of Neuroscience Functionalism Thinking Machines (Animals, Martians, etc) An excellent resource… http://consc.net/guide.html

Dualism There are three basic kinds of dualism Substance (Descartes) Mental substances are different from physical substances. Not only are the properties of a mental state are different from the properties of a physical state but they are made of different things Property The qualitative nature of consciousness is different from merely physical states – it is emergent from those physical states but not the same Predicate Mental predicates are necessary for a complete theory of the world Mental predicates cannot be reduced to physical predicates E.g. water = h2o vs pain=firing of c-fibres

How do mind and body interact? Interactionism To at least some degree mental states can cause physical states and vice versa. Epiphenomenalism Mental events are caused by physical events but not vice versa Parallelism Mental events and physical events are in a kinds of continual harmony but neither causes the other

Another dualist problem - location The strangeness of the mental Mental events have two unique properties Subjectivity Intentionality Physical events have Extension is space and time Are causally connected How do we locate subjectivity and intentionality in space and time?

Physicalism Physicalism is essentially the metaphysical claim that everything is physical It is distinguished from materialism (everything is matter) by the fact that physicalists include such entities as energy, magnetism, gravity, etc. which we agree are physical but it’s not clear that they are made of ‘matter’ An important part of physicalism is the notion of supervenience. E.g. Lewis, (1986, On the Plurality of Worlds) A dot-matrix picture has global properties -- it is symmetrical, it is cluttered, and whatnot -- and yet all there is to the picture is dots and non-dots at each point of the matrix. The global properties are nothing but patterns in the dots. They supervene: no two pictures could differ in their global properties without differing, somewhere, in whether there is or there isn't a dot (p. 14).

A Problem for Physicalism Qualia – the feelings/qualities of things Jackson (1986, What Mary Didn’t Know) A famous neuroscientist is confined to a black and white room. She learns about the world via black and white media such as tv, computers, newspapers, etc. Through study, she learns (knows) all that physical theory can teach her. When she is released into the world of colour, it is clear that she did not know what it is like for both herself and others to see colours.

Another Problem for Physicalism Intentionality The ‘aboutness’ of thought is difficult to explain within a physicalist account of meaning via a dispositional theory of meaning (a word means what its use suggests e.g. we use the word blue to talk about blue things) Kripke (1982, Wittgenstein on Rules and Private Language: An Elementary Exposition) Imagine a situation in which (a) the dispositional theory is true (b) the word ‘red’ means red for a speaker S (c) the speaker misapplies the word e.g. they describe a white object viewed through red lenses as red (they don’t know it’s white) So S applies ‘red’ to things which are ‘either red or white but viewed through red lenses’ Therefore the combination of a, b and c leads to a contradiction The dispositional account of meaning cannot be true

Identity Theory of Mind The identity theory of mind claims that mental events and physical events are one and the same (not merely correlated) Two classic papers are: Is Consciousness a brain process? (U.T. Place, 1956) The “Mental” and the “Physical”? (H.Feigl, 1958) Identity theorists, in part, argue that a problem has arisen because philosophers have confused ‘meaning’ and ‘reference’ E.g. ‘very bright star in the morning’ and ‘very bright star in the evening’ have different meanings but both statements refer to the planet venus In this sense, identity theory is ‘contingent’ and subject to empirical investigation

Anomalous Monism This philosophy of mind comes from the writings of Donald Davidson It is based on three basic principles At least some mental events causally interact with at least some physical events Events related by causes must follow strict laws There are no strict laws that for mental events can relate, explain, predict other events In order to resolve some of problems associated with this line of reasoning Davidson invokes a final principle Supervenience If two events share all their physical properties they will also share all their mental properties

Eliminative Materialism Feyerabend (1963) argued that our intuitions (‘folk psychology’) about the relationship between mind and body are simply wrong. Any form of materialism or physicalism automatically excludes the mental – there are no mental events If mental events are physical events (and only physical events) then our lack of a language to describe those physical events is just that and no more The Churchlands (Paul & Patricia) are two of the most vocal exponents of this viewpoint: Eliminative Materialism and the Propositional Attitudes (1981) Neurophilosophy: Toward a Unified Science of the Mind Brain (1986)

Functionalism Functionalism is the claim that what makes a mental state a particular mental state is not it’s ‘internal constitution’ but rather the role is plays in relation to sensory input, behaviour, and other mental states. Functionalism is not committed to a physicalist view of the world Functionalism allows different physical instantiations of the same ‘mental states’ A functional description of the mental state pain may be something of the form ∃x∃y∃z∃w ( x tends to be caused by bodily injury & x tends to produce states y, z, and w & x tends to produce wincing or moaning). For a more extensive discussions of functionalism see Lewis, (1972, “Psychophysical and theoretical identifications” and Block (1980, Readings in the Philosophy of Psychology, Volumes 1 & 2)

Problems for Functionalism Absent and Inverted Qualia It is possible to imagine a being whose mental state is exactly that as described by a functionalist account but whose mental state has no ‘quale’ It is possible to imagine a being whose mental state is exactly that as described by a functionalist statement but whose ‘quale’ is not the same as another person/being A conceivable zombie It is possible to imagine a being (zombie) without mental states who is functionally identical to other beings that possess mental states

Thinking Machines (Animals, Martians, etc) If functionalism is correct then machines, animals, martians can ‘think’. However, Searle (1980, Minds, Brains and Programs) argued that this is clearly impossible A English language speaker is locked in a room. In that room there are some Chinese symbols and some rules written in English for manipulating those symbols. Some more symbols are passed into the room and by using the rules the person can pass the correct symbols out the room. An onlooker looks at the input and output to the room and concludes that the person in the room understands Chinese. However, the person in the room clearly doesn’t understand Chinese and would tell you so. The ability to manipulate symbols in a functional way is not evidence that a machine is actually thinking.

Replies to the Chinese Room Experiment The systems reply While the individual in the room doesn’t understand the ‘complete system’ does understand The robot reply A robot moving, seeing and acting in the world would acquire the necessary understanding The brain simulator reply Instead of instantiating the rules via a person in the room you used a complete simulation of a Chinese person’s mind. This would understand. The other minds reply How do you know that other Chinese speakers ‘understand’ Chinese The intuitions reply Perhaps Searle’s intuitions about ‘understanding’ are simply wrong.