20. Epiphenomenalism

William Kingdon Clifford was a panpsychist. His friend, Thomas Huxley, was an epiphenomenalist. Both agreed in adopting the physicalist principle of the closedness of the physical world (World 1). In Clifford's words ([1886], p. 260): "all the evidence that we have goes to show that the physical world gets along entirely by itself. . .".

The difference between epiphenomenalism and panpsychism is mainly this.

(1) Epiphenomenalism does not assert that all material processes have a psychical aspect, and

(2) Epiphenomenalism is very far from regarding conscious states or processes as the things in themselves, as at least some of the post-Leibnizean and post-Kantian panpsychists do.

(3) Epiphenomenalism may be linked with a parallelist view (like a partial panpsychism) or it may allow for a one sided causal action of the body upon the mind. (The latter view is liable to clash with Newton's third law — the equality of action and reaction.¹) I will criticize here a parallelist epiphenomenalism; but nothing in my criticism depends on this choice.

Huxley ([1898], p. 240; cp. pp. 243f.) puts his epiphenomenalism very well: "Consciousness . . . would appear to be related to the mechanism of [the] body, simply as a . . . [side] product of its working, and to be as completely without any power of modifying that working as the [sound of a] steam-whistle which accompanies the work of a locomotive ... is without influence upon its machinery."

Thomas Huxley was a Darwinian — in fact, the first of all Darwinians. But I think that his epiphenomenalism clashes with the Darwinian point of view. For from a Darwinian point of view, we are led to speculate about the survival value of mental processes. For example we might regard pain as a warning signal. More generally, Darwinists ought to regard "the mind", that is to say mental processes and dispositions for mental actions and reactions, as analogous to a bodily organ (closely linked with the brain, presumably) which has evolved under the pressure of natural selection. It functions by helping the adaptation of the organism (cp. the discussion of organic evolution in section 6, above). The Darwinian view must be this: consciousness and more generally the mental processes are to be regarded (and, if possible, to be explained) as the product of evolution by natural selection.

The Darwinian view is needed, especially, for understanding intellectual mental processes. Intelligent actions are actions adapted to foreseeable events. They are based upon foresight, upon expectation; as a rule, upon short term and long term expectation, and upon the comparison of the expected results of several possible moves and countermoves. Here preference comes in, and with it, the making of decisions, many of which have an instinctual basis. This may be the way in which emotions enter the World 2 of mental processes and experiences; and why they sometimes "become conscious", and sometimes not.

The Darwinian view also explains at least partly the first emergence of a World 3 of products of the human mind: the world of tools, of instruments, of languages, of myths, and of theories. (This much can be of course also admitted by those who are reluctant, or hesitant, to ascribe "reality" to entities such as problems and theories, and also by those who regard World 3 as a part of World 1 and/or World 2.) The existence of the cultural World 3 and of cultural evolution may draw our attention to the fact that there is a great deal of systematic coherence within both World 2 and World 3; and that this can be explained — partly — as the systematic result of selection pressures. For example, the evolution of language can be explained, it seems, only if we assume that even a primitive language can be helpful in the struggle for life, and that the emergence of language has a feedback effect: linguistic capabilities are competing; they are being selected for their biological effects; which leads to higher levels in the evolution of language.

We can summarize this in the form of the following four principles of which the first two, it seems to me, must be accepted especially by those who are inclined towards physicalism or materialism.

(1) The theory of natural selection is the only theory known at present which can explain the emergence of purposeful processes in the world and, especially, the evolution of higher forms of life.

(2) Natural selection is concerned with physical survival (with the frequency distribution of competing genes in a population). It is therefore concerned, essentially, with the explanation of World 1 effects.

(3) If natural selection is to account for the emergence of the World 2 of subjective or mental experiences, the theory must explain the manner in which the evolution of World 2 (and of World 3) systematically provides us with instruments for survival.

(4) Any explanation in terms of natural selection is partial and incomplete. For it must always assume the existence of many (and of partly unknown) competing mutations, and of a variety of (partly unknown) selection pressures.

These four principles may be briefly referred to as the Darwinian point of view. I shall try to show here that the Darwinian point of view clashes with the doctrine usually called "epiphenomenalism".

Epiphenomenalism admits the existence of mental events or experiences — that is, of a World 2 — but asserts that these mental or subjective experiences are causally ineffective byproducts of physiological processes, which alone are causally effective. In this way the epiphenomenalist can accept the physicalistic principle of the closedness of World 1, together with the existence of a World 2. Now the epiphenomenalist must insist that World 2 is indeed irrelevant; that only physical processes matter: If a man reads a book, the decisive thing is not that it influences his opinions, and provides him with information. These are all irrelevant epiphenomena. What matters is solely the change in his brain structure that affects his disposition to act. These dispositions are indeed, the epiphenomenalist will say, of the greatest importance for survival: it is only here that Darwinism comes in. The subjective experiences of reading and thinking exist, but they do not play the role we usually attribute to them. Rather, this mistaken attribution is the result of our failure to distinguish between our experiences and the crucially important impact of our reading upon the dispositional properties of the brain structure. The subjective experiential aspects of our perceptions while reading do not matter; nor do the emotional aspects. All this is fortuitous, casual rather than causal.

It is clear that this epiphenomenalist view is unsatisfactory. It admits the existence of a World 2, but denies it any biological function. It therefore cannot explain, in Darwinian terms, the evolution of World 2. And it is forced to deny what is plainly a most important fact - the tremendous impact of this evolution (and of the evolution of World 3) upon World 1.

I think that this argument is decisive.

To put the matter in biological terms, there are several closely related systems of controls in higher organisms: the immune system, the endocrinal system, the central nervous system, and what we may call the "mental system". There is little doubt that the last two of these are closely linked. But so are the others, if perhaps less closely. The mental system has, clearly, its evolutionary and functional history, and its functions have increased with the evolution from lower to higher organisms. It thus has to be linked with the Darwinian point of view. But epiphenomenalism cannot do this.

An important but separate criticism is this. If applied to arguments, and our weighing of reasons, the epiphenomenalist view is suicidal. For the epiphenomenalist is committed to arguing that arguments or reasons do not really matter. They cannot really influence our dispositions to act — for example, to speak or to write — nor the actions themselves. These are all due to mechanical, physico-chemical, acoustical, optical and electrical effects.

Thus the epiphenomenalist argument leads to the recognition of its own irrelevance. This does not refute epiphenomenalism. It merely means that if epiphenomenalism is true, we cannot take seriously as a reason or argument whatever is said in its support.

The problem of the validity of this argument was raised by, among others, J. B. S. Haldane. It will be discussed in the next section.

¹ The principle is re-affirmed by Einstein ([1922]; [1956], chapter 3, p. 54) when he says: ". . . it is contrary to the mode of thinking in science to conceive of a thing. . . which acts itself, but which cannot be acted upon."