08. Mind-Brain Type-Identity Theory

• Ontological reduction is the claim that mental properties are identical to physical properties of the brain.
• Mind-Brain Type-Identity Theory is the theory that mental properties are identical (ontologically reducible) to physical properties of the brain.
• A state type is a type of mental state.
• A token is an instance of a type.
• The claim that mental state types are identical to brain state types is much stronger than the claim that mental states and brain states are identical as tokens.
• Empirical observation and Ockham’s razor support the claim that mental properties are identical to physical properties of the brain.
• The principle of causal closure supports the claim that mental properties are identical to physical properties of the brain.
• Mind-brain type-identity theory can cohere with what we know empirically, i.e. neuroscientific explanations.
• Mind-brain type-identity theory does not violate the principle of causal closure.
• An identity relation is the simplest explanation of correlations between mental and physical properties compared to supervenience or causation.
• The objection from multiple realisability comes from Hilary Putnam.
• The multiple realisability objection to Mind-brain Type-identity theory is that the claim that one and the same mental state can be ‘realised’ (have its function performed) by different physical states.
• P1: If mental property type M is identical to human brain property type B, then any instance of M must be an instance of B.
• Multiple Realisability Premise: It is empirically plausible that some instances of M are not instances of B, they are instances of non-human brain properties and therefore M-Type is not identical to B-Type
• Lewis’ reply to the multiple realisability objection is that our everyday concept of pain is actually the concept pain-in-humans.
• Lewis says that species-relativity is implicitly built in; when we think about a dog in pain, we implicitly use the concept pain-in-dogs.
• Lewis’ reply does not succeed in avoiding the problem of intra-species variation.
• Different individuals from within the same species can have different brain states while experiencing the same mental state type.
• Correlation is a relationship between two things whereby one always accompanies the other
• Correlation is distinct from identity
• The correlation between mental and brain properties can be explained by causation, supervenience and identity
• We want to be able to say that one mental state is identical to one physical state, not one mental state being identical to multiple physical states
• Intra-species variation claims that individual humans can differ in terms of which brain states correspond to certain mental states
• Intra-species variation claims that different individuals from within the same species can have different brain states while experiencing the same mental state