26.The New Promissory Materialism

A somewhat half-hearted retreat from the identity theory has become fashionable lately. It is a retreat into what may be described as a "promissory materialism". The popularity of promissory materialism is perhaps a reaction to some striking criticisms which have been advanced against the identity theory in recent years. These criticisms show that the identity theory is hardly compatible with ordinary language or with common sense. At any rate, it seems that the new promissory materialism accepts that, at the present time, materialism is not tenable. But it offers us the promise of a better world, a world in which mental terms will have disappeared from our language, and in which materialism will be victorious.

The victory is to come about as follows. With the progress of brain research, the language of the physiologists is likely to penetrate more and more into ordinary language and to change our picture of the universe, including that of common sense. So we shall be talking less and less about experiences, perceptions, thoughts, beliefs, purposes and aims; and more and more about brain processes, about dispositions to behave, and about overt behaviour. In this way, mentalist language will go out of fashion and be used only in historical reports, or metaphorically, or ironically. When this stage has been reached, mentalism will be stone dead, and the problem of mind and its relation to the body will have solved itself.

In support of promissory materialism it is pointed out that this is exactly what has happened in the case of the problem of witches and their relation to the devil. If at all, we now speak of witches either to characterize an archaic superstition, or we speak metaphorically or ironically. The same will happen with mind language, we are promised: perhaps not so very soon — perhaps not even during the life span of the present generation — but soon enough.

Promissory materialism is a peculiar theory. It consists, essentially, of a historical (or historicist) prophecy about the future results of brain research and of their impact. This prophecy is baseless. No attempt is made to base it upon a survey of recent brain research. The opinion of researchers who, like Wilder Penfield, started as identity theorists, but ended as dualists (see Penfield [1975], pp. 104f.) is ignored. No attempt is made to resolve the difficulties of materialism by argument. No alternatives to materialism are even considered.

Thus it appears that there is, rationally, not more of interest to be found in the thesis of promissory materialism than, let us say, in the thesis that one day we shall abolish cats or elephants by ceasing to talk about them; or in the thesis that one day we shall abolish death by ceasing to talk about it. (Indeed, did we not get rid of bedbugs simply by refusing to talk about them?)

Promissory materialists like, it seems, to state their prophecy in the at present still fashionable jargon of linguistic philosophy. But I suggest that this is inessential; and a physicalist might drop the jargon of linguistic philosophy and reply to what I have said here along the following lines.

Physicalist: "You claim, as a critic of physicalism, that reports about subjective experience, and empirically testable theories about subjective experience, constitute evidence against our thesis. However, as you yourself [1034 (b)] always emphasize, all observation statements are theory-impregnated; and as suggested by yourself ([1957 (i)] = [1972 (a)], chapter 5), it has happened in the history of science that statements about facts, and well-tested theories, have been corrected when they have been explained by later theories. Thus it is certainly not impossible that what we now regard as statements about subjective experience will, in the future, be explained and corrected by physicalist theories. If this happens, subjective experience will be left in much the same position as, say, demons or witches are now: it will be part of a theory which was once accepted, but which has now been discarded; and the old evidence for it will have been reinterpreted and corrected."

While I do not wish to suggest that it is impossible that things may happen as the physicalist says here (see my [1974 (c)], p. 1054), I do not think that this argument can be taken seriously. For it says no more than that no observational evidence is final, beyond the possibility of correction, and that all our knowledge is fallible. This is true, of course; but it is not enough to be used, on its own, as a defence of a theory against empirical criticism. The argument, as it stands, is too weak. As mentioned before, it would be as applicable to question the existence of cats or of elephants as it is to question the existence of subjective experience. While there is always a risk involved in accepting evidence and arguments like those here used by me, it seems to me reasonable to take the risk. For all the physicalist offers is, as it were, a cheque drawn against his future prospects, and based on the hope that a theory will be developed one day which solves his problems for him; the hope, in short, that something will turn up.