Functionalism as the view that mental states are functional states defined by their causal role, the input, internal state and output structure and its multiple realisability, the contrast with type identity theory and behaviourism, and the objections from the possibility of inverted qualia and absent qualia and from the China brain or nation thought experiment.

What this dot point is asking

AQA wants you to explain functionalism as the view that mental states are defined by their causal role (their relations to inputs, other mental states and outputs), to see how this lets the same state be multiply realised and improves on both behaviourism and type identity theory, and to evaluate the objections from inverted qualia, absent qualia and the China brain (or Chinese nation) thought experiment.

What functionalism claims

How it improves on its rivals

Objections from qualia

• Inverted qualia. Imagine someone functionally identical to you whose colour experiences are systematically inverted (they have a red-experience where you have a green-experience) while all their inputs, outputs and dispositions match yours. If this is possible, then functional role does not fix qualia, so functionalism leaves out the felt quality of experience.
• Absent qualia (Block's China brain / Chinese nation). Suppose the entire population of China were organised to mimic the functional organisation of a brain, sending signals to one another so that, collectively, they realise the functional state of, say, pain. Intuitively this system would have the right functional organisation but no conscious experience at all. If so, functional organisation is not sufficient for qualia, and functionalism omits consciousness.

Replies

Functionalists may deny the conceivability of inverted or absent qualia, argue that the China brain would have experiences (we just cannot imagine it from the inside), or restrict the theory to the intentional mental states (beliefs, desires) while treating qualia separately. The persistence of the qualia objections is what motivates the wider debate about consciousness.

Replies in more depth

The standard functionalist defence treats the qualia objections as a challenge to be absorbed rather than a refutation. Against inverted qualia, some functionalists argue that a fully specified functional role would actually fix the quality, because colour experiences stand in fine-grained similarity and contrast relations (red is experienced as more like orange than like green, and as a warm rather than cool colour). If the functional description captures all those relations, an inverted spectrum that preserved every relation might be impossible, and an inversion that broke them would show up functionally and so would not be a genuine counterexample. Against the China brain, functionalists press the question of why we are so confident the system lacks experience: the intuition may simply reflect that the realising parts (a billion people) look nothing like a brain, which is an appeal to the very physical resemblance functionalism rejects. A more concessive move restricts functionalism to the intentional states (beliefs, desires, intentions), where the theory is strongest, and hands qualia to a separate account, but this concedes that functional organisation alone does not deliver the whole mind.

A useful way to organise an essay is to see that functionalism faces a dilemma about how it specifies the functional roles. If roles are specified purely in terms of physical inputs and behavioural outputs, the theory risks collapsing back towards behaviourism and inherits the qualia worry directly. If roles are specified in richer mental terms (the input is the experience of damage), the theory threatens circularity, defining mental states partly by reference to mental states. The Ramsey-Lewis technique answers this by defining all the mental terms together as a single implicitly defined network, so no one term is taken as primitive, but a strong evaluation should show awareness of the cost on each horn.