To take another example, Sigmund Freud, in proposing his famous Oedipus complex, concluded that infant boys had a strong incestuous attraction to their mothers and that society should therefore enact ''the most stringent prohibitions'' to prevent such behavior. Experiments have shown, Wilson says, that humans have an intense natural aversion to incest. Many species of animals, too, avoid incest. The most likely explanation, Wilson says, is that the aversion is a consequence of evolution. Incestuous unions produce offspring with a high chance of genetic defects, and evolution selects against that.
Society therefore needs no prohibitions against incest.
Wilson worries about that attitude. Consilience is a provocative book, worth reading simply for the opportunity to spend time with one of today's great scientific minds. Nonscientists will find Wilson a congenial and approachable host. He isn't quite successful in making the case that the humanities and the arts are amenable to scientific investigation. He contends, however, that such issues as ethnic conflict, arms escalation, overpopulation, abortion, and environmental crises ''cannot be solved without integrating knowledge from the natural sciences with that of the social sciences and humanities.'' Unifying human knowledge might be difficult or impossible, he admits.