Functionalism

Functionalism is an interesting physicalist theory because it does not always have to be physicalist.

The AQA definition of Functionalism is: All mental states can be characterised in terms of functional roles which can be multiply realised.

So functionalism is not about what a mind is made of, but what it does. Therefore, technically, a functionalist could be either a physicalist or a dualist.

What is Functionalism?

Functionalism defines mental states as functional states within an organism.
For example, the functional role of pain is to cause an unpleasant sensation that causes the organism to get away from the thing that’s causing it harm.
That function is what mental states, such as pain, are. It is kinda like a series of outputs that fulfill a certain functional role.
Functions should be understood within the context of the entire mind, so including other mental states and physical outputs.
Part of the function of pain is to cause other mental states, like a belief that you are in pain, or a desire for the pain to stop as well as the physical outputs associated with this (running away etc).

Why is Functionalism a bit different?

Functionalists think that what the mind is, is not what it is made from, but what it does.
So while dualists and physicalists argue about what makes up the mind (non-physical vs physical parts), Functionalists ask what the mind's function is.
For example, a mouse trap is normally made from wood and metal. However it could be made of plastic or any other material as long as it fulfills the function of catching a mouse. A group of humans could form a mousetrap with their bodies, even. A mouse trap is not defined by what it is made from, but by what it does.
If I used my hand to cut a sandwich in half, my hand has fulfilled the function of being a knife and cutting something.
A functionalist could be a dualist or a physicalist because they could think a mind could be made from physical stuff or non-physical stuff. As long as something performs the function of a mind, it is a mind.

Hilary Putnam: The Nature of Mental States

As with many theories in Philosophy, Funcationalism begins by criticising other physicalist theories.
Hilary Putnam makes the multiple realisability argument as an objection to type identity theory. So, in an essay this argument can be used to criticise MBTIT and also support functionalism.
Putnam would say that mental states such as pain can be experienced by a human, an octopus or an alien. The key feature of pain is its function.
The function of pain could be an unpleasant sensation to cause a desire for the pain to stop and that causes the animal or alien to get away from the thing that’s causing it harm.
This function is not specific to any physical thing or species, and so anything that serves this function, whether in a human, an octopus, an alien, would count as pain.
The same mental state can be multiply realised and are therefore not reduced to one thing in particular, but something's function. EG: A knife can be made out of many different materials but it has one function which is to cut.

Problem: Inverted Qualia

What if my experience of green was like your experience of red?
For example, if my qualia when I look at the sea are similar to your qualia when you look at fire.
When we both look at the sea, our mental states would be functionally identical. They would both, for example, cause us to believe “the sky is blue”. The output would be us saying "That's a nice blue sky :)"
And since our mental states are functionally identical, functionalism must say they are the same mental state.
But they’re clearly not the same. My qualia are different from yours.
The inverted qualia objection to functionalism states that if two mental states function in the same way, they ARE the same mental state. However, if inverted qualia is true and we experience colours differently then although functionally similar, the phenomenal aspect is different. Therefore the mental states are not identical and functionalism is wrong.

Response: Anti-Dualist
- You don't have to accept this criticism to functionalilsm if you reject the idea of qualia altogether. If there is no qualia and there is no subjective phenomenal mental state, then that means that the two ARE functionally identical and functionalism survives.

Physicalist Response:
- If people have different qualia while looking at the same thing, that means that they could have different functional outputs. Blue is associated with calm, red is associated with anger. So, yes phenomenally the mental states are different, BUT this means they are also functionally different as well. Our mental states when we look at the sea are NOT functionally identical because they are phenomenally different. Therefore, functionalism survives.

Problem: Ned Block's China Brain

The thought experiment:
Imagine we have a complete functional description of human mental states
A human body is connected to the entire population of China and every person in China is linked to other people via two-way radios (simulating neurons) and instructed to communicate according to this functional description.
Some of these people (neurons) are linked to the inputs, and some to the outputs of the body
The system produces exactly the same output as a normal human, with all internal processing being functionally identical.
Why does this criticise functionalism?
Functionalists say yep this is a human mind, because it fulfills the function of one. It's not what it's made of, it's what it does.
Ned Block says that is ridiculous and obviously the population of china is not representative of consciousness because it seems absurd and counter-intuitive.
The individual people all have their own separate consciousnesses, which is fine, but there is no unified subject of experience at the level of the whole system. There is no one big conscious that is representative of the China Brain.
It is, therefore, not the functional role alone that creates consciousness, but there has to be something else whether that is qualia, something biological etc.
This china brain lacks genuine consciousness and also lacks qualia. This means functionalism is incomplete.

Problem: The Mary Knowledge Argument

Mary knows all the physical and functional facts about the mental state of seeing red while she is in the black and white room
But when she leaves the black and white room for the first time and sees red she learns something new, what it is like to see the colour red.
So, there is more to the mental state of seeing red than simply the physical and functional facts.
So, functionalism is wrong – there is more to mental states than their function
In the original argument, it is argued that all the physical facts would not be enough for Mary to know what it’s like to see red if she’d never seen it for herself.
We could respond similarly to how we respond to Property Dualists: Mary only gains new Ability Knowledge. The only thing that changes is what she can DO, not what she knows about the world. Mary gains a new skill, not a new fact. Since abilities can be described functionally, no extra qualia facts are required.