mind brain identity theory Flashcards
what is an ontological reduction and how is it a theory of ontological reduction
where one type of entity is shown to be in reality the same as another type of entity, often of a more fundamental level of reality
—> water is identical to H20, water really is just H20
—>the mental state of pain is just C-fibres firing
- there are not two different things, the same instead
- MBIT is a theory of ontological reduction as it ontologically reduces mind and brain to be the same
what does MBIT claim about mental states
- mind is identical to the brain
- mental properties are just physical properties
- all mental states are identical to brain states (ontological reduction)
- although, the terms “mental state” and “brain state” are not synonymous (no analytic reduction)
what does type identity theory claim about mental states
- each token of the type “mental state” is identical to each token of the type “brain state”
- every mental state can be ontologically reduced to, and directly correlated to, a neurological state in the brain
- strong claim about the nature of the mind
- mental states like “fear” are identical to human brain states
- different brains will have different mental states
that does token identity theory claim about mental states
- some tokens of the type “mental state” are identical to some tokens of the type “brain state”
- some mental states can be ontologically reduced to, and directly correlated to, some neurological states in the brain
- weaker claim that type identity theory, makes less of a substantial claim about the nature of the mind
- may be that some mental states are really brain states, but others aren’t, and could still be non-physical
what evidence is there to suggest that the mind is just the brain
- empirical evidence of correlation between changes in brain states and mental states –> Phineas Gage
- MBIT moves beyond mere identification of correlation to a stronger claim that these two things are the same
how could ockhams razor support MBIT
- MBIT posts the fewest amount of entities whilst still remaining the most explanatorily powerful
- the physical world can be explained by science, as can the brain
- if the mind is just the brain, then it too can be explained by science
what is a nomological dangler and how does Smart use this to support MBIT
- something that cannot be accounted for by the normal laws of nature, they are described by science
- if dualism were true, then mental states were really non-physical, then they would be nomological danglers
- they would be anomalous, since they alone cannot be explained by science
- therefore unlikely that mental states are distinct from physical states
what are 4 reasons why MBIT might be compelling
- explanatory power of neuroscience –> has made progress, can explain far more and better than dualism can
- coherence with science –> MBIT is fully coherent as if the mind is just the brain then the mind can be investigated via the brain, which is exactly what neuroscience does
- solves the problem of interaction –> if the mind and brain are identical then there is no problem of interaction, we know and can investigate how the brain interacts with itself, the body and the outside world
- solves the problem of other minds –> if minds are just brains then we just need to identify whether a being has a brain to know if they have a mind
- also folloes okhams razor, intuitive
what are the 5 objections to MBIT
- multiple realisability of mental states (Putnam) —> most crucial
- substance dualism applied to identity theory
- property dualism applied to identity theory
- the location problem
- identity theory violates Leibniz’s law (Saul Kripke)
what does it mean for mental states to be multiple realisable in MBIT
- if it can be shown in many different physical systems, such as human brains, dog brains, machines
- for example pain is a mental state experienced by humans and dogs however a dogs brain is different to a humans, it is conceivable that this is the case for aliens too
- this would mean that mental states aren’t identical to brain states
- this is different to multiple realisability in behaviourism which instead means mental states can be instantiated via a variety of different behaviours
how does type identity theory deny the multiple reliability of mental states
- it claims the mind is identical to the brain, so all the mental states we can conceive of and experience are mental states that are specific to human minds and therefore human brains
- so it limits minds to human beings, non-human animals, machines and aliens have different physical structures so cannot have the same mental states as us
outline formally the objection to MBIT about multiple realisability
P1) Each type of mental state is multiply realisable through more than one distinct type of physical state
P2) If each type of mental states is multiple realisable through more than one distinct type of physical state, then it cannot be identical to any specific type of physical state
C1) Therefore, no type of mental state is identical to any specific type of physical state
P3) According to type identity theory, each type of mental state is identical to a specific type of physical state
C2) Therefore, type identity theory is false
how might token identity theory respond to the issue of multiple realisability
- token theory claims that only some mental states are identical to some brain states
- so there will be some human mental states that are identical to some human brain states, but also some that aren’t
- there mental states are those, like pain, that are multiply realisable
- therefore it is conceivable that some mental states are multiple realisable and some aren’t
what is the weakness of token identity theory
- leaves open the possibility for many mental states to not be identical to brain states
- so it might be the case that no mental state is identical to brain states
how does Descartes indivisibility argument provide an objection to MBIT and how would a type theorist respond
- argument proves mind and body cannot be the same thing since they do not share any properties (Leibniz’s Law), so physicalism must be false, the mind and brain aren’t identical
- response that his argument “begs the question”, logical fallacy meaning the conclusion of the argument is assumed in the argument itself
- Descartes assume that the mind is different from the body and has different properties
outline Descartes conceivability argument applied to MBIT
P1) It is conceivable that for any type of mental state, there can be a being that has that mental state without having the brain state with which it is identical (as the identity theorist claims)
P2) What is conceivable is also metaphysically possible
C1) Therefore, it is metaphysically possible that for any type of mental state, it can exist in the absence of the brain state with which the identity theories claims it is identical
P3) If one thing can exist in the absence of another then they aren’t identical
C2) Therefore, mental states cannot be identical to brain states and MBIT is false
how might Descartes conceivability argument, applied to MBIT fails
- MBIT response that it isn’t conceivable to have a mental state without a corresponding physical state, so P1 is false
- they might rely on physical evidence of correlation between brain activity and mental activity
how does the knowledge argument pose as an issue for MBIT
- qualia and phenomenal facts in general cannot be shown to be physical facts, so if they exist, then there exist mental states than aren’t ontologically reducible to physical states
- so type identity theory is false but token identity could still be true
how might Chalmers conceivability (philosophical zombie) argument pose as an issue for MBIT
- the argument shows the possibility of physically identical duplicates existing which lack phenomenal properties
- if physicalism were true then this would not be possible but since it is then physicalism cannot be true
- as a physicalist theory, this means that identity theory is false
what is the location problem and why is it an issue for MBIT and why is it a strong argument
- brain states have a physical location, we can identify where they are empirically
- if MBIT is true then mental states, as they are physical states, would have a location too
- example of the colour red, we cannot point to a particular part of the brain to locate this mental state
- whilst physical states do indeed have a location, mental states do not, so according to Leibniz’s Law, they cannot be identical
- inductive argument with empirical evidence so is strong
outline how Saul Kripke argued that both versions of identity theory violate Leibniz’s Law
P1) identity theory is the view that mental states are identical to brain states
P2) it also claims that the identity of mental and brain states is discovered via empirical research, which is also how we gain matters of fact according to Hume
C1) Therefore, identity theory is a contingent relation, it is established via evidence and it is never contradictory to say that X is not identical to Y (that pain is not identical to C-Fibres moving)
P3) However, identity theory claims that the mind must be identical to the brain, it isn’t possible that the identity relation between mind and brain could be contingent (this would mean we could say the mind is the whole body, or some particular part, and there would be no contradiction)
P4) Identity is in fact a necessary relation - it is a logical relation not an empirical one, evidence cannot establish identity claims and so neuroscience cannot demonstrate that the mind is in the brain
C2) Therefore, since this necessary relation has not been logical established there can be no identity relation between mental states and brain states so both type and token identity theory are false
