mind brain type identity theory

Question 1

two types of identity

Answer 1

• qualitative identity: sometimes when we say that things are identical, we mean they have the same qualities (e.g. identical twins are qualitatively identical)
• numerical identity: sometimes when we say that things are identical, we mean that they are one in the same (e.g. Peter Parker is spiderman)

Question 2

mind brain type identity theory

Answer 2

• J.J.C. Smart argued that since neuroscience is increasingly discovering that our mental states are correlated with brain states, then it is preferable to hold the view that our mental states are numerically identical with brain states
• this means that they are ontologically reducible to brain states
• although they are not analytically reducible (our mental concepts do not mean the same thing as our brain concepts)

Question 3

other examples of ontological reduction from science

Answer 3

• water is H20
• science will tell us how our mental states are reducible to brain states
• e.g. pain is c-fibres firing

Question 4

difference with behaviourism

Answer 4

• behaviourists claim that the meaning of mental terms can be explained in terms of behaviour
• e.g. Ryan is in pain means Ryan is clutching his arm and crying
• mind brain type identity theory does not claim that our mental concepts mean the same thing as our brain concepts
• the identity is not analytic
• it is a scientific discovery that the two are identical, just like the discovery that water is H20

Question 5

Ockham’s razor

Answer 5

• can be used as an argument for mind brain type identity theory (and all versions of physicalism)
• ‘do not multiply entities beyond necessity’
• if two theories can both explain our observations, we should prefer the simpler one
• if the theory that there is just the brain is just as good as the theory that there is a mind and a brain, then we should accept the first option

Question 6

objection: dualist arguments applied to mind brain type identity theory

Answer 6

• introspection revels a range of thoughts, emotions and experiences that seem totally unlike neurophysiological states
• Chalmers’ zombie argument suggests that we can conceive of beings who have exactly the same brain states and without any mental states
• if this is possible, then mind brain type identity theory must be incorrect

Question 7

response to: dualist arguments applied to mind brain type identity theory

Answer 7

• we should not expect our subjective experiences to be like the physical reality they are perceiving
• e.g. our colour perceptions allow us to distinguish between physical structures on the basis of the kind of light they reflect or absorb
• counter-response: when we are talking about our brain states and the way they appear to us, it doesn’t make sense to distinguish between them unless our subjective awareness is distinct from the brain state itself, something that identity theorists deny

Question 8

objection: multiple realisability of mental states - recovering from brain damage

Answer 8

• patients who have suffered damage to their brain (e.g. a stroke) will lose certain functions (e.g. speech)
• over time, other parts of the brain can learn to take over this function
• but, according to identity theory, if this is a different brain state then it must be a different mental state

Question 9

objection: multiple realisability of mental states - different kinds of brains

Answer 9

• different kinds of brain: according to mind brain type identity theory, two mental states can only be of the same types if they are identical with the same type of brain state, this would mean that those with different kinds of brains couldn’t have the same mental states
• e.g. animals: pain in octopi are caused by o-fibres firing, whereas in humans it is caused by c-fibres firing
• aliens: if aliens have silicon based brains (rather than carbon based brains that human have), then aliens and humans could not have any of the same beliefs

Question 10

response to: multiple realisability of mental states - different kinds of brains

Answer 10

• identity theorists can accept that different kinds of brain state can result in the same mental state, just not multiple kinds of mental state corresponding to the same brain state
• e.g. like the relationship between a person and their shadow
• counter-response: this means there are many different kinds of pain, octopus pain, human pain, alien pain, etc
• what do all of these states have in common that means we should call them pain?
• we could say that it is because they all result in the same behaviour
• but then this makes the theory look like behaviourism

Question 11

objection: the irreducibility of intentionality

Answer 11

• intentionality: the ‘aboutness’ of certain mental states
• we don’t just believe, we believe something, we don’t just desire, we desire something
• many of our mental states are about something else
• brain states are not anything, they just are
• this suggests that intentionality cannot be reduced to brain states, therefore at least some mental states are not identical with brain states

Question 12

response to: the irreducibility of intentionality

Answer 12

• perhaps the brain represents the things they are about
• it could be that the brain state that is a belief about a car represents a car
• counter-response: our brain could be said to represent a walnut, but that doesn’t make them about walnuts