Consilience: The Unity of Knowledge.

Edward O. Wilson Alfred A. Knopf, $26,322 p.

Like the body of Osiris in the myth, our corporate store of knowledge is now being torn into a thousand pieces which are distributed among ever-growing crowds of specialists. Communally, we know more and more. But it becomes less and less clear who actually knows any part of it. Can we do anything to stop this fragmentation?

The sociobiologist Edward O. Wilson, rightly horrified by this situation, is making a proposal. Wilson is a scientist who really likes and respects the arts, so he is not just destructive. But in his quest for unity he is determined to combine arts and sciences inside a single formal system. He sees this kind of unification as an absolute demand of reason. And the system he chooses just happens to be the one now employed by modern science. He writes:

There is intrinsically only one class of explanation. It traverses the scales of space, time, complexity to unite the disparate facts of the disciplines by consilience, the perception of a seamless web of causes and effects....Consilient explanations are congenial to the entirety of the great branches of learning.

The central idea of the consilience world view is that all tangible phenomena, from the birth of stars to the workings of social institutions, are based on material processes that are ultimately reducible, however long and tortuous the sequences, to the laws of physics [emphasis mine].

All explanations, then, are causal explanations and all causes are material causes, so all questions are, at the deepest level, questions for physics. How does this require us actually to relate the arts with the sciences? Wilson's answer is always that we must bring the arts within the range of scientific methods. Thus, for instance:

Artistic inspiration common to everyone in varying degree rises from the artesian wells of human nature....Creativity is therefore humanistic in its fullest sense. Works of enduring value are those truest to these origins. It follows that even the greatest works of art might be understood fundamentally with knowledge of the biologically evolved epigenetic rules that guided them [emphasis mine].

How will this work? It is not easy to see. When we try to understand, say, War and Peace, or The Marriage of Figaro, our efforts at understanding are not questions about causes at all. Those efforts set out in quite a different direction, inquiring directly about the meaning of the work itself. They ask how it shifts our general picture of life. They also look inward, reshaping our own ideas in response to that shift. We try, in fact, to see what this particular work is saying - indeed, despite the postmodernists, most of us try to see what this particular author is saying. The "understanding" that results is therefore not a causal story. Like much other understanding, it is essentially the imaginative grasp of a new pattern - a distinctive pattern of thought and feeling. People who cannot respond personally in this way to works of art notoriously do not understand them, whatever rules they may claim to have discovered.

Naturally, some grasp of facts does come in here as well, especially over literature. We need some knowledge of the historical and social background of these works. But, again, most of the relevant questions about that background are not causal questions in the sense used in the physical sciences. For instance, the aristocratic way of life that appears in both War and Peace and The Marriage of Figaro was indeed, historically speaking, one "cause" of both the French and Russian Revolutions. But historical causes like this are highly complex general influences, not standard entities linked to their effects by universal laws like the causes invoked in physics.

This point about multiple explanations is not (as Wilson seems to think) some vitalist fantasy, adding bogus extraphysical forces to the ordinary causal scene. Of course, normal causal processes are going on in people's bodies all the time. But those processes are just the relatively fixed background against which exceptional and complex social activities, such as works of art and revolutions, occur. They cannot explain those activities.

Similarly, no doubt our capacity for producing art did indeed develop according to the "biologically evolved epigenetic rules" that Wilson mentions. But these rules were general ones, facilitating every kind of art. Knowledge about them might answer general questions on how art as a whole evolved but could not help us to understand a particular artwork, any more than knowing how our mathematical faculties evolved could help us understand the calculus. Mathematicians are a different kind of expert from evolutionists. These two kinds of explanation do not compete. They supplement each other, lying in quite different directions.

The painful truth is that there are lots of kinds of explanation. The thought patterns which we use in understanding language, or in doing mathematics, or in trying to grasp each other's motives, or in historical research, or in responding to works of art, are not just superficial layers of folk psychology laid over a single basic pattern prescribed by physical science. Instead, they are appropriate devices evolved for dealing with many quite different kinds of human situation, only one of which confronts science.

Their plurality does not mean that we have a fragmented world. It is like the plurality which we find at the front of our atlases where many maps of the world - political, physiographic, climatological, and the rest - confront us without implying that we live in many worlds. Each map, each pattern, selects from the great welter of our experience the details needed for a certain aspect of our life. And what holds the various aspects together is not any imposed formal structure. It is simply their common context, the fact that life itself is a whole.

The idea of supplementing this moderate, realistic kind of unity by finding a single basic formal pattern was, of course, a cherished project of seventeenth-century rationalists in the early days of modern science. Descartes, Spinoza, and Leibnitz all worked on it with intense dedication and between them they exhausted its possibilities. Thereby they showed once and for all that this kind of formal unification is not workable and cannot, therefore, be demanded by reason. If the various provinces of our intellectual world are to work together usefully today - and by God they had better - they must do it by cooperating harmoniously, respecting each other's differences as separate enterprises. They cannot evade this by the kind of one-way assimilation which Wilson himself once rightly described as cannibalism.

Consilience is, on the whole, a much more charitable book and much better adapted to promote intellectual cooperation than Wilson's early work. The frankly cannibalistic academic imperialism of Sociobiology is gone. So is the distorted language of "selfishness." There is much fascinating discussion of the arts and much lively speculation about human nature - a much misunderstood notion which Wilson quite rightly defends - all fueled by a real wish for intellectual harmony. Yet there still remains a strange, unnecessary commitment to devices for unification which cannot work and which threaten that harmony. Since this kind of mistake is still widespread, it is very much to be hoped that Wilson overcomes it and writes us another vigorous book which will make real reconciliation possible.

Mary Midgley is the author of many books on philosophy, including Science and Salvation (Routledge, 1992).