Materialism in the philosophy of mind

Materialism – which, for almost all purposes, is the same as physicalism – is the theory that everything that exists is material. Natural science shows that most things are intelligible in material terms, but mind presents problems in at least two ways. The first is consciousness, as found in the ‘raw feel’ of subjective experience. The second is the intentionality of thought, which is the property of being about something beyond itself; ‘aboutness’ seems not to be a physical relation in the ordinary sense.

There have been three ways of approaching these problems. The hardest is eliminativism, according to which there are no ‘raw feels’, no intentionality and, in general, no mental states: the mind and all its furniture are part of an outdated science that we now see to be false. Next is reductionism, which seeks to give an account of our experience and of intentionality in terms which are acceptable to a physical science: this means, in practice, analysing the mind in terms of its role in producing behaviour. Finally, the materialist may accept the reality and irreducibility of mind, but claim that it depends on matter in such an intimate way – more intimate than mere causal dependence – that materialism is not threatened by the irreducibility of mind. The first two approaches can be called ‘hard materialism’, the third ‘soft materialism’.

The problem for eliminativism is that we find it difficult to credit that any belief that we think and feel is a theoretical speculation. Reductionism’s main difficulty is that there seems to be more to consciousness than its contribution to behaviour: a robotic machine could behave as we do without thinking or feeling. The soft materialist has to explain supervenience in a way that makes the mind not epiphenomenal without falling into the problems of interactionism.