In and out of the mind

Colin McGinn

  • Renewing Philosophy by Hilary Putnam
    Harvard, 234 pp, £19.95, January 1993, ISBN 0 674 76093 X

In a neglected passage in The Problems of Philosophy Bertrand Russell unapologetically writes:

A priori knowledge is not all of the logical kind we have been hitherto considering. Perhaps the most important example of non-logical a priori knowledge is knowledge as to ethical value ... We judge, for example, that happiness is more desirable than misery, knowledge than ignorance, goodwill than hatred, and so on. Such judgments must, in part at least, be immediate and a priori. Like our previous a priori judgments, they may be elicited by experience ... But it is fairly obvious that they cannot be proved by experience ... Knowledge as to what is intrinsically of value is a priori in the same sense in which logic is a priori.

Thus, for Russell, ethical knowledge enjoys the privileges and securities that the rationalists discerned in our knowledge of logic and mathematics: immediacy, certainty, necessity. It is a paradigm of what true knowledge should be like, and contrasts sharply, in Russell’s epistemology, with the empirical knowledge we seek in science. There Russell finds only uncertainty, indirectness, questionable inference. We know the world of science merely ‘by description’, as a projection from what we are immediately ‘acquainted with’, and we must rely on indirect, subjective ‘signs’ if we are to venture any objective knowledge at all. The nature of the objects described by science is inherently conjectural; even the space that contains them is beyond our faculties of direct awareness. Most disturbing of all, the basic principle of scientific inference – namely, induction – is incapable of empirical support, and subject to radical (and rational) scepticism. According to Russell’s conception of human knowledge, then, ethics ranks a good deal higher than science on the scale of epistemic virtue; it occupies a place our faculties can reach. To compare ethical knowledge unfavourably with scientific knowledge would be absurd. Science is by no means the standard against which all other claims to knowledge are to be judged.

Nor is this position merely eccentric or even obsolete: essentially the same structure emerges from the conception of human knowledge powerfully advocated by Noam Chomsky. Think of the human mind as a modular congeries of special-purpose facilities – organs for knowing – which are biologically based and innately specified. Then science, for Chomsky, is simply the result of a happy convergence between objective truth about the world and the particular epistemic organs we happen to possess. There is no sense in which these faculties were designed with scientific knowledge as their goal – in contrast with (say) our knowledge of language. Science is possible for us only because it is a remote by-product of some independently selected faculty; and it will encounter obstacles of principle where fact and faculty fail to match. We are not natural scientists, but rely on a kind of biological luck. This is why science is so hard to acquire and admits so much variation between individuals – in marked contrast to language.

Moreover, according to Chomsky, it is plausible to see our ethical faculty as analogous to our language faculty: we acquire ethical knowledge with very little explicit instruction, without great intellectual labour, and the end-result is remarkably uniform given the variety of ethical input we receive. The environment serves merely to trigger and specialise an innate schematism. Thus the ethical systems of different cultures or epochs are plausibly seen as analogous to the different languages people speak – an underlying universal structure gets differentiated into specific cultural products. So, while science must depend on faculties whose biological purpose is not itself science – or anything very close to science – ethics seems far more deeply embedded in our original mental design. Perhaps the innate system of commonsense psychology, installed to negotiate our social relations, contains the resources for generating the basic principles of ethics. But there is surely no prospect that knowledge of quantum physics or evolutionary theory will be found to stem thus directly from anything with a well-defined biological function. On the Chomskyan model, both science and ethics are natural products of contingent human psychology, constrained by its specific constitutive principles; but ethics looks to have the securer basis in our cognitive architecture. There is an element of luck to our possession of scientific knowledge that is absent in the case of our ethical knowledge.

The full text of this book review is only available to subscribers of the London Review of Books.

You are not logged in