‘These people do not sit on the beach and listen to the steady roar of the pounding surf. They sit on the beach and listen to the aperiodic atmospheric compression waves produced as the coherent energy of the ocean waves is audibly redistributed in the chaotic turbulence of the shallows … They do not observe the western sky redden as the sun sets. They observe the wavelength distribution of incoming solar radiation shift towards the longer wavelengths as the shorter are increasingly scattered away from the lengthening atmospheric path they must take as terrestrial rotation turns us slowly away from their source.’
A humorous picture, perhaps, but there is a serious purpose behind Canadian-born philosopher Paul Churchland’s 1979 vision of a future comprehended by science. In time, Churchland argues, as our scientific understanding advances, ‘folk psychology’ – our ordinary ways of thinking and expressing our mental lives, in terms of beliefs, desires, intentions and so on – will fall out of the picture, to be replaced by accurate concepts and descriptions drawn principally from neuroscience.
In company with most of today’s philosophers and scientists, Churchland is a materialist (or physicalist). Impressed by the undeniable successes of science, he believes that the world and everything in it, including human beings, are composed of matter; that the universe is exclusively physical and explicable, in principle at least, purely in terms of physical laws and processes. One consequence of this is that nothing can be non-physical: there is no place for the spiritual or supernatural (including gods), nor for minds and mental phenomena to the extent that these are considered to lie outside the physical realm. It is true that Churchland’s ‘eliminative materialism’, so called from its ambition to jettison the concepts of folk psychology altogether, puts him at the radical end of materialist views. Yet the problem that he seeks to address is one faced by any materialist. We are all immediately conscious of our consciousness and of the rich array of mental phenomena with which it is populated. How can this teeming mental life, essentially subjective and private, possibly be accommodated within a purely physical account of the world – the kind of account, that is, that would be given by science, which is essentially objective, nonperspectival and publicly accessible?
‘Nobody has the slightest idea how anything material could be conscious. Nobody even knows what it would be like to have the slightest idea about how anything material could be conscious. So much for the philosophy of consciousness.’
Jerry Fodor, US philosopher, 1992
Difficult relations Advances in neuroscience have established beyond doubt that mental and physical states are intimately related. With the exception of eliminativists like Churchland, who regard mental concepts as some sort of primitive, soon-to-be-obsolete constructs, materialists agree, broadly, that conscious experience emerges from, or is somehow determined by, electrochemical activity within the mass of neural fibres that constitutes the brain. Views differ considerably, however, on the nature of this ‘emergence’.
At one time many materialists believed that a particular mental state could in principle be identified with a particular brain state, so that pain, for instance, might be correlated directly with the excitation of a certain set of neural fibres; pain, on this view, would not be some kind of by-product of a particular brain event – it would be (identical to) that brain event. However, so-called ‘multiple realizability’ – the recognition that a single mental state can be produced by several different physical states – put paid to such naive identity theories. Today, materialists sometimes introduce a non-symmetrical dependency relation called ‘supervenience’, according to which the mental supervenes on the physical in the sense that the former is wholly determined by the latter, yet the latter could occur without the former. A parallel might be drawn with the aesthetic qualities of objects, which are determined by certain underlying physical features of the objects, yet remain distinct from those features. Without further elucidation, however, it seems that the notion of supervenience merely relocates the problem, rather than solving it.
Amongst recent materialists, probably the most influential and widely held view on the relation between mind and body is functionalism, a theory that grew out of an earlier, flawed position known as behaviourism (basically, the thesis that mental phenomena could be translated, without loss of content, into kinds of behaviour or dispositions to behaviour).
‘Without consciousness the mind–body problem would be much less interesting. With consciousness it seems hopeless.’
Thomas Nagel, US philosopher, 1974
According to the functionalist account, mental states are functional (not physical) states: a certain mental state is identified as such by virtue of the role or function it has in relation to various inputs (the causes that typically bring it about), the effects it has on other mental states, and various outputs (the effects it typically has on behaviour). A significant problem for functionalism (as for behaviourism before it) is that it casts no light on mental states themselves and focuses purely on their relations to one another and to inputs (various kinds of stimuli) and outputs (various kinds of behaviour). In effect, functionalism says nothing about consciousness per se and so fails to address what is, for most people, the aspect that is most in need of explanation.
the condensed idea
Matter over mind