Mind-Brain Type Identity

The most Physical Physicalist idea of the mind that you can get.

Specification's Definition: All mental states are identical to brain states (‘ontological’ reduction) although ‘mental state’ and ‘brain state’ are not synonymous (so not an ‘analytic’ reduction).

What is Mind-Brain Type Identity Theory?

The AQA definition, and so the definition you should use for 3 markers and for defining it in essays, is: All mental states are identical to brain states (‘ontological’ reduction) although ‘mental state’ and ‘brain state’ are not synonymous (so not an ‘analytic’ reduction).
Mental states reduce to brain states, so mental states ARE just brain states.
Consciousness and sensations are only brain processes.
An example often used in Philosophy of the Mind is:

The mental state of pain is reducible to c-fibres firing.

Analytic vs Ontological Reduction

This is an important distinction for this topic, and it's the most confusing part.
Analytic reduction is when we show that one thing can be broken down into something else without losing any of its meaning.
For example: Triangle can be reduced to 3-sidedness without any loss of meaning and are therefore analytically reduced to each other. You cannot deny an analytic reduction.
Analytic reductions are true in the meaning of the words.
Ontological reductions are when two things ARE the same thing, but we understand them differently. They are exactly the same in terms of sharing the same spatial coordinates, the same space/time qualities. But they're conceptually different.
For example, Christmas Day and the 25th December are the exact same thing but one is just a date and the other is a holiday. Conceptually different despite being the same.

JJC Smart: Sensations and Brain Processes

JJC Smart is the brain behind MBTIT.
Smart claims that mental states ontologically reduce to brain states.
What this means is that mental state ARE brain states, but we understand them differently.
Pain is ontologically reduced to c-fibres firing; what this means is that pain literally IS just the brain's c-fibres sending off electrical impulses, but we also understand pain to be all the feelings and negative emotions.
Mental states reducing to brain states is NOT an analytic reduction because we can deny them without causing a contradiction.

Analytic vs Ontological Reduction (again)

Again, I think this is the most complicated part of this topic, so I just wanna go through it once more.
Ontological Reductions: if X reduces to Y, then X and Y are the same thing. But we interpret X and Y differently.
Analytic Reduction: Two ways of saying the exact same thing, no interpretation necessary.
Small test: Which of these is Ontological Reduction, which are Analytic?

Water is H2O

A bachelor is an unmarried man

Lightning is electrical discharge

Shannon is a good Philosophy teacher

Christmas Day is the 25th December

A sister is a female sibling

The phrase “Entia non sunt multiplicanda praeter necessitatem” (“Entities should not be multiplied beyond necessity”) is often attributed to William of Ockham, but it does not appear in his surviving works. The earliest known use is by John Punch in 1639, and it was later popularised by Libert Froidmont in 1649, who credited Ockham with the principle.

Portrait_of_Sir_Isaac_Newton,_1689_(brightened).jpg

"We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances." - Isaac Newton

"Whenever possible, substitute constructions out of known entities for inferences to unknown entities." - Bertrand Russell

Support: Occam's Razor

We can use Occam's Razor to support MBTIT, and just about any physicalist theory.
Occam's Razor states: "Do not multiply entities beyond necessity".
So, simply put, the simplest explanation is the best one.
What this means is that when two theories make the same prediction, the theory that requires the smallest number of entities in its explanation is probably the correct one.
Dualism and Physicalism both try to explain the nature of mental states. Dualism does this with:
1. Physical body.
2. Non-physical quality (soul/mind/qualia etc)

Physicalism does this with:
1. Physical body

Therefore, physicalism relies on the fewest amount of entities in its explanation and it probably the correct one.
If physicalism can explain everything about the mind just with a physical substance, there is no need to bring in anything else.

Problem: Location

If MBTIT claims that pain is reducible to c-fibres firing, that implies that pain has a distinct location within the brain.
So, presumably you could put someone into an MRI scanner and see exactly where the c-fibres, and thus the pain, is located.
However, pain doesn't always have the same physical location.
If you locate someone's c-fibres, you've not located where their pain is.
Remember, ontological reduction means that the two things are identical and share the same spatial coordinates.
But, they clearly don't. C-fibres are in the brain, and your pain is located elsewhere. They do not share the same location and cannot be identical.

Problem: Multiple Realisability

This is a theory put forward by Hilary Putnam which states that pain (and other mental states) cannot be reduced to brain states because mental states are multiply realisable.
What this means is that mental states can be realised in multiple kinds of systems, not just human brains.
Putnam argues that a theory like MBTIT fails because it assumes that if animals such as humans, birds, reptiles, or octopi were to experience pain, they would all require some single “physical-chemical kind” common to each of them, which is not the case.
Due to the diversity in neuroanatomy between animals, it seems to suggest that brain states alone are not enough to understand mental states.
This attempts to demonstrate that MBTIT is too narrow because it does not allow for organisms without human brains to have mental states.

Problem: Zombies

The Zombie argument is mainly used against behaviourism, and to support Property Dualism, but we can use it to argue against MBTIT.
Zombies are entities that do not have mental states / conscious experience and the point of them is to show that purely physical facts are not enough to describe a person fully.
A person and a zombie could be physically identically the same, but because one does not have the mental state they are fundamentally different.
So, a zombie could have the same brain state without the mental state that MBTIT says they are identical to. A zombie's c-fibres firing doesn't mean they are actually in pain.
This suggests that physical facts alone do not guarantee conscious experience. Consciousness might be something other than just brain states.