Is Diversity the Mother of Invention?

THE LEVER OF RICHES: TECHNOLOGICAL CREATIVITY AND ECONOMIC PROGRESS, By Joel Mokyr. New York: Oxford University Press. 349 pp., $24.95 IS America losing its technological edge? Are its invention and innovation - its much-vaunted ``Yankee ingenuity'' - giving ground to other nations? If so, how can the drift be stemmed? If not, why are Americans so worried about competition from Japan, Germany, and the Asian tigers?

It is into this nest of current questions that Joel Mokyr sets his book, ``The Lever of Riches.'' He doesn't answer them, nor does he try: This is a book about history, ending abruptly at 1914. But his examples are so comprehensive, his knowledge so detailed, and his conclusions so broad and firmly drawn that the reader comes away full of insight into the issues - and oddly comforted about the prospects for the global future.

First, the insight. The reigning metaphor for Professor Mokyr, who teaches economics and history at Northwestern University, is that of the free lunch. In economic terms, that lunch - that appearance of getting something for nothing - arises in the world of commerce whenever there is ``an increase in output that is not commensurate with the increase in effort and cost necessary to bring it about.'' Such advances come most frequently, he argues, as a result of technological creativity, which he describes as a ``change in the application of information to the production process in such a way as to increase efficiency.''

The bulk of his book teases out the history of technological creativity from antiquity to the 20th century. A potentially dull subject, it is enlivened by the wealth of Mokyr's examples. Part of the interest comes from the recognition that so many things we take for granted were once inconceivable: Imagine a world without stirrups, wheelbarrows, water mills, or the crank, all inventions of medieval Europe.

Part of the interest, too, comes from the surprises of historical juxtaposition. Mokyr notes, for example, that Rome in AD 100 had ``better paved streets, sewage disposal, water supply, and fire protection'' than the European capitals of 1800, and that four centuries before the Industrial Revolution of Europe, China was on the brink of industrialization and then slipped into technological decline.

And part of the interest certainly lies in a range of delightful and revealing quotations that reflect Mokyr's capacious reading - Aristotle, for instance, observing that ``no man can practice virtue who is living the life of a mechanic or laborer,'' or an Arab proverb, dating from the days of the square-riggers, that ``no one but a madman or a Christian would sail to windward.''

But the book's heart is a 41-page chapter titled ``Understanding Technological Progress.'' Carefully and thoughtfully, Mokyr examines a bevy of theories that seek to explain why technological creativity arises in some societies and not in others.

Is it, he asks, a matter of life expectancy, since short lives leave little time or incentive to improve knowledge? Is it nutrition, whereby a lack of proper diet produces ``a lethargic and supine personality'' not given to invention? Is it related to one's willingness to bear risks, or to one's geographic environment, or to a need to reduce high labor costs?

Or is it related (and here he waxes more philosophical) to the role of science, which before the 17th century tended to see the world through biological rather than mechanistic metaphors and did not teach that man could have systematic dominion over its forces?

Or is it rather a religious question of whether man should have that dominion? Religion, Mokyr argues, will support innovation only to the extent that religious beliefs enhance ``the willingness to challenge and manipulate the physical environment.'' Or is it a questions of secular values - since, after all, the desirability of useful innovations depends on whether one's culture puts a high value on usefulness in contrast to beauty, virtue, or knowledge for its own sake?

While Mokyr shies away from espousing any single cause, he clearly likes some less than others - dismissing, for instance, the popular notion that war is the mother of invention by arguing that, throughout history, peace has proved far more conducive to technological progress.

Scholar that he is, he revels in the multiplicity of explanations. Which is what is oddly comforting about his book. For as with his explanations, so with societies themselves: Diversity appears to be the key.

If it is true, as many historians have observed, that no single society ever retains its technological lead for very long, then what most matters is the preservation of a broad range of cultures in which inventiveness might arise.

``As long as some societies remain creative,'' he notes, ``others will eventually be dragged along.'' The food may shift tables, in other words, but it's still a free lunch.

And that, in the end, is one of the powerful contributions of his thesis. These days, there's plenty of talk about diversity. It figures in discussions of the workplace and the nursery school, the arts and the academy, the preservation of endangered species. It must also figure in discussions of technology and the global economy. Maintain the diversity of societies, says history, and you ensure the continuity of technological creativity. Destroy that diversity, and sooner or later you kill off the free lunch.