Philosophy of Mind

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Philosophy of Mind

• Lecture Three Type-Type Identity

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Previously

• Weve looked at dualism.
• Specifically, weve seen dualism giving us
  alleged reasons why physicalism is wrong
  (impossibility of thinking etc.) and moving from
  that to dualism.
• So we still have problems for physicalism.
• Its just unclear whether these problems are
  motivations for dualism.
• So time now to turn to the materialist/physicalist
  enterprise.

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Types and Tokens

• But before we dive in, we need some more
  terminology.
• We need to introduce types and tokens.
• Take washing machines.
• Imagine I have two Samsung washing machines.

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Types and Tokens

• There is one type of kitchen utility present.
• Namely, the type of washing machine.
• However, there are two tokens of that type.
• If there were three washing machines, there would
  be one type, and three tokens of that type.

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Types and Tokens
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Types and Tokens

• You can also have tokens of different types.
• For instance, imagine that there was a Samsung
  washing machine and a Zanussi washing machine.

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Types and Tokens
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Types and Tokens

• You can also have tokens of different types.
• For instance, imagine that there was a Samsung
  washing machine and a Zanussi washing machine.
• There we have one type (washing machine) of which
  there are two tokens.
• There is also the type Zanussi product of which
  there is one token.
• There is also the type Samsung product of which
  there is one token.

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Types and Tokens

• So in general x and y can be tokens of type T
  without both being tokens of type T.
• Heres another example of the type/token
  distinction.
• How many letter types are there in the following?

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Types and Tokens
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Types and Tokens

• So in general x and y can be tokens of type T
  without both being tokens of type T.
• Heres another example of the type/token
  distinction.
• How many letter types are there in the following?
• So there are two.

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Types and Tokens

• How many tokens?

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Types and Tokens

• How many tokens?
• Four.
• So there are four letter tokens, but two types of
  letter.
• Each type having two tokens.

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Types and Tokens

• But this lecture is on neither the philosophy of
  laundry, nor of typology.
• So what has this got to do with the mind?
• Simply put, there are mental types and mental
  tokens.

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Mental Types

• For instance, some mental states are pain states.
• You have them when youre in pain.
• So imagine you punch me.
• I enter into a certain mental state (of being in
  pain).
• Again you punch me.
• Again, I have a mental state of pain.
• Again you punch me!
• And again I have a mental state of pain.
• Thats three pain tokens.
• But all of the same type.

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Mental Types

• Similarly, if I punched you, you would be in
  pain.
• Youd have your pain token and Id have my pain
  token.
• Wed both be in pain not in virtue of both having
  the same pain token
• but having mental tokens of the same type.

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Types and Tokens

• So hopefully that gives you an idea of the
  difference between types and tokens.
• This is going to be important. So if you dont
  know the difference, say so now.

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Physicalism

• There are two varieties.
• Type-type and token-token.
• Funnily enough the definitions are
• Type-Type Identity Every mental type is
  identical to a physical type.
• Token-Token Identity Every mental token is
  identical to a physical token.
• One is about Types, one is about Tokens, and as
  those things are very different the physicalist
  theories are very different.

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Type-Type Identity Theory

• We will concentrate on Type-Type today.
• Although a lot of what is said applies generally
  to physicalist theories.
• Whilst we briefly look at some criticisms of
  type-type, it isnt until week 7 when we get to
  the main problems posed against it.

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Type-Type Identity Theory

• So what does Type-Type Identity involve?
• Well, we have mental types
• Being in pain
• Being in love
• Desiring to play Halo
• And we have physical types
• Being in a certain brain state
• A state of certain C-fibres firing

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Type-Type Identity Theory

• The TTIT identifies those types.
• So the type of being in pain just is a certain
  physical type.
• A type of certain brain state.
• So the pain tokens in my head are also tokens of
  that brain state.
• Anything in that brain state is in pain anything
  in the pain state falls under that type.

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Type-Type Identity Theory

• Think of it like this
• Being a car
• Being a voiture
• A Ferrari is a token of both types because those
  two types are the same.
• So your pain token is a brain state token as well
  because those types are the same.

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Why be a physicalist?

• So weve got our first type of physicalism.
• Chronologically it comes next.
• So first there is dualism, then behaviourism
  (from last year), then physicalism in the form of
  TTIT.
• So the early arguments for physicalism were
  actually arguments for TTIT.
• However many will count as arguments for
  token-token identity theory (which we look at in
  more detail later).

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Why be a physicalist?

• So why should we believe physicalism?
• Well, it solves various problems
• Correlation
• Causal interactionism
• Causal closure

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Why be a physicalist?

• We can note that there is a strong level of
  correlation between brain states and mental
  states.
• For instance, you care greatly about the well
  being of your brain because you think that
  impacts on your mental life.
• Senile Dementia.
• Visual Agnosia.
• Brain surgery (and onion smells).

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Why be a physicalist?

• Even dualists must admit there is a close
  correlation between brain states and mental
  states.
• Now imagine youre John McClane.
• You find a correlation between the presence of
  the butler in a given area, and the presence of
  the murderer killing his victims.
• One excellent explanation is that the butler is
  the murderer.

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Why be a physicalist?

• Similarly, physicalists can happily explain the
  correlation.
• We get a correlation between mental states and
  brain states because mental states are brain
  states.
• The state being in pain just is certain c-fibres
  firing.

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Why be a physicalist?

• So its more parsimonious.
• JJC Smart argues that the dualist theory has more
  than it needs.
• Once weve got the brain states and the evidence
  of correlation its just simpler to identify
  them.
• Just as its odd to think there is rampant causal
  overdetermination, its odd to add unnecessary
  mental states distinct from physical ones.

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Why be a physicalist?

• It also solves the problem of causal
  interactionism (if indeed there is one).
• How can mental states interact with the physical
  ones?
• Easily!
• They are the physical ones.

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Why be a physicalist?

• Ditto for causal closure.
• Last lecture we saw how being a physicalist
  avoided the problem of certain events being
  caused both by brain states and by mental states.
• Theres no problem given physicalism as they are
  the same state.
• No weirder than George Bush and the President of
  the USA being responsible for the invasion of
  Iraq.

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Why be a physicalist?

• So it solves problems.
• Note also that it comes from a scientific
  discovery.
• Physicalism is known a posteriori.
• Only by going out into the world can we come to
  know that mental states are brain states.
• This fuels Armstrongs argument.

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Armstrongs Argument for Physicalism

• Armstrong asks us to consider genes.
• Long before we discovered DNA, we knew about
  genes.
• Mendel noted that characteristics were passed on
  from parent organisms.
• The entity responsible for this inheritance was
  termed a gene.

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Armstrongs Argument for Physicalism

• Research into DNA uncovered that it was portions
  of DNA that caused the hereditariness of certain
  characteristics.
• So an identification was made
• Portions of DNA genes
• The identification was made, so says Armstrong,
  because we defined a gene as being that thing
  that played a certain causal role.

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Armstrongs Argument for Physicalism

• So when we turn to mental states, Armstrong says
  we should do the same.
• Pain is that state which causes you to yelp
  withdraw your hand from the stove utter
  sentences such as I am in a lot of pain right
  now.
• So according to Armstrong when we identify the
  physical state that causes you to do these things
• then that is the mental state of pain.

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Epistemological Problems

• Before finishing, I want to quickly look at a
  common strawman objection to this theory.
• If pain is actually a state of C-fibres firing
  there is this issue.
• People who know nothing about C-fibres firing can
  still know an awful lot about their own mental
  states.
• So they cant be one and the same thing.

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Epistemological Problems

• There seems to be a use of Leibnizs Law taking
  place here.
• The law says that if x and y are (numerically)
  identical then they are qualitatively identical.
• Example Gordon Brown and the prime minister
  being different heights.

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Epistemological Problems

• So if state x and y are identical then they
  should have the same properties.
• So if we know about one, we must know a lot about
  the other.
• But this is all (allegedly) a strawman.
• LL fails in lots of contexts namely intensional
  contexts.
• Believing, fearing, knowing etc. are intensional
  contexts.

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Epistemological Problems

• Clearly LL does not hold in such contexts.
• Lois Lane knows Superman can fly.
• Clark Kent is numerically identical to Superman.
• It does not follow from LL that Lois Lane knows
  Clark Kent can fly.

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Epistemological Problems

• Clearly LL does not hold in such contexts.
• Lois Lane knows Superman can fly.
• Clark Kent is numerically identical to Superman.
• It does not follow from LL that Lois Lane knows
  Clark Kent can fly.
• Why? Because knowing that p is an intensional
  context.

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Epistemological Problems

• Similarly, you might know a lot about pain.
• You might know nothing about C-fibres firing.
• But as knowledge is intensional, that doesnt
  indicate that they are distinct.

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Next Lecture

• In future lectures we will see criticisms of
  Type-Type Identity Theory.
• And turn to the Token-Token alternatives.
• Next lecture, though, a general problem for
  physicalism.