The weakness of materialism

The argument

The materialist position this argument targets holds that a mental state simply is a particular physical state of the brain — that to be in pain is to be in one specific neural configuration. Putnam argued that this could not be true, and the objection turns on the range of creatures to which pain applies. We know that cats, dogs, reptiles, birds and molluscs feel pain. But their nervous systems are not like ours: a mollusc's neural organisation differs from a mammal's so profoundly that there is no candidate physical state common to both. If pain were identical to a specific brain state, then either these animals do not feel pain — which we have good reason to reject — or they feel it in virtue of physical states quite unlike the human one. The second option is fatal to the identity claim, because a property identical to state X cannot also be instantiated by states unlike X. This led Putnam to conclude that the relationship between mental states and physical activity in the brain is not one-to-one. The same mental state can be multiply realised — brought about by many different physical arrangements, from many different stimuli. What makes something pain, on this account, is not what it is made of but what it does: the role it plays in registering damage, prompting avoidance and shaping subsequent behaviour. A state filling that role is pain, whatever substrate happens to fill it. That is the functionalist answer to the mind-body problem, and the multiple realisation aspect of it is what has drawn many to favour functionalism over materialist positions. It preserves what materialism got right — that mental states depend on physical goings-on — while explaining something materialism cannot: how creatures built very differently can nonetheless share a mental state.

Context

The strongest arguments for functionalism stem from the weaknesses of the competing mind-body solutions. Putnam, for example, believed materialism was too narrow in its scope. The idea that mental states could be reduced solely to physical occurrences lead to the emergence of a one-to-one relation between the two; we feel pain due to c-fibre stimulation, and nothing else. X causes Y. Without X, Y does not occur.

Premises

Counter-arguments

Qualia Functionalism cannot explain the qualia phenomenon, also known as “what it is like” to have a mental state or an experience. In characterising mental states in causal terms, there is no room to characterise the feeling behind mental states. Someone who sees greens instead of reds might still respond to the stimulus of red in the same way as someone who sees the red. However, their qualia- or the feeling behind the experience- would be wildly different.

Rejecting the premises

Just because others do not offer a comprehensive explanation doesn't mean functionalism does.