ETs and a search for wobbly truths

四月 12, 2002

The publishers' handout accompanying this impressive volume exclaims that "philosophy will never look the same again; science transforms the concepts of truth, objectivity, necessity, contingency, consciousness and ethics". Well, science has of course been doing that transforming on and off for some time. What Robert Nozick does in this book is to use certain recent movements in particular sciences to throw light on these traditional philosophical topics. His main lamp-standards are those areas of modern physics that have proved hardest to describe in intelligible terms; theories of evolutionary psychology that suggest that we are preadapted to understand the world in certain ways rather than in others; and neurobiological theories on matters such as blindsight that have an impact on problems about consciousness.

The first half of the book deals with "The structure of the objective world", examining our notions of truth, objectivity and necessity. It asks:

"Is truth absolute, or is it possible for truth to be relative?" - a question that obviously interests many of us. New readers should be warned, however, that Nozick does not pursue it in the direction that they might expect. He concentrates entirely on the truth of propositions in difficult areas of physics, drawing practically all his examples from questions on matters such as quantum mechanics, string theory and 11-dimensional space-time.

These topics do actually raise interesting questions about truth, because it is so hard to see just how their statements relate to what we think of as the real world. Indeed, Richard Feynman remarked that in his own area of electrodynamics their relation to it was very obscure, even though the concepts that he used worked well in practice. This means that the idea of truth as a simple "correspondence with the facts" wobbles and is hard to apply in these areas. Whatever "facts" are being mentioned here often do not seem to be approachable except in terms of the theories that are themselves under investigation. That is why some people have deemed this kind of talk to be only an arbitrary social construction.

Yet, as Feynman says, it works, and it is continuous with a whole web of other much more ordinary propositions that have a more normal kind of meaning. Physicists do have ways in which, given time, they can use the rest of their science to sort out and apply the new theories. So (says Nozick) we do not have to choose between rejecting the new theories and rejecting the whole concept of objective science: "There is another response that is possible, that science is rational and objective, not in spite of the complicating factors but because of them. The complicating factors play a role in the advance of science. They contribute to science's rationality and objectivity."

He concludes that we must indeed drop the simple view of truth as correspondence, but this does not mean abandoning the ideals of objectivity and truth. It means that our concepts of them must become subtler and more sensitive. We do manage to talk about the real world. But in doing so we use various conceptual schemes - different grids or pairs of spectacles that pick out different elements in it.

In one of his very few non-scientific examples (to which many readers will surely cling like drowning sailors), Nozick discusses an imaginary inter-planetary encounter: "That we and the Alpha Centaurians assign the same non-modal predicates to an object shows that we are talking of the same object, even though we and they do not pick out the same subset of these predicates as salientI Identity is based upon, and is a function of, essential properties... which [are] based upon, and (are) a function of the interests and needs that we have (or that the Alpha Centaurians have)."

Thus both parties can be saying what is true, but neither should claim to have the whole truth.

This is surely right. Nozick discusses admirably the subtleties that are needed for these revamped concepts. He ends, as he has so often done, with a reasonable, humane and attractive solution to an awkward dilemma. But his strategy of starting on it from this angle is surely a strange one, and not just because these examples are difficult and technical. The trouble is that they are so untypical of the cases where we normally have to talk about truth, so remote from the places where that concept raises real problems. In theoretical physics, language is being used to reach out, so to speak, into the void. It may not matter much there whether we talk of these highly abstract theories as aiming at truth or just at usefulness. But in everyday life the opposite of truth is falsehood . That word does not appear in the index to this book.

Nozick's discussion of consciousness is interesting but not, I think, strikingly original. But what is striking is the immense respect that he shows, throughout the book, for recent speculations in evolutionary psychology. Repeatedly, he accounts for particular ways of thinking by suggesting that they have perhaps become innate because they were attended by evolutionary advantage. This is a suggestion that often seems persuasive when it is applied to extremely general tendencies, but it surely gets less and less so when applied, as it is here, to specific patterns.

Moreover, it has the drawback of blocking other kinds of explanation. Thus, in discussing ethics, Nozick writes: "The capacity for following norms... is innate. It will be helpful to consider this as a specialised capacity - a 'normativity module'. (I think it unlikely that it arose as a side-effect of some other function of a large and complicated brain.)" This suggestion seems to isolate morality from other thinking, substituting an assumed evolutionary function for an examination of its continuity with the rest of our lives. Nozick's arguments do better, I think, when left to stand on their own feet than they do when they are supplied with flimsy support of this kind.

Mary Midgley was formerly senior lecturer in philosophy, University of Newcastle upon Tyne.

Invariances: The Structure of the Objective World

Author - Robert Nozick
ISBN - 0 674 00631 3
Publisher - Harvard University Press
Price - £23.95
Pages - 448

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