Consilience: The Unity of Knowledge
By Edward O. Wilson
Alfred A. Knopf; 332 pages; $26
In his 1755 Dictionary, Samuel Johnson derided the idea that a dictionary "can embalm his language, and secure it from corruption and decay, that it is in his power to change sublunary nature, and clear the world at once from folly, vanity, and affectation." Few people today know what he meant by the lovely word sublunary. Literally, it means "beneath the moon," and Johnson was alluding to an ancient, widespread belief that there was an unbreachable division between the cosmos, thought to be pristine, lawful, and unchanging, and our grubby, chaotic Earth below. The division was already obsolete by Johnson's time: Newton had shown that a single set of laws pulled the apple toward the ground and kept the moon in its orbit around Earth.
E.O. Wilson has chosen another lovely but little-known word, consilience, as the title and theme of his new book. Literally "jumping together," consilience means the linking of facts and theory across disciplines into a single coherent system of explanation. That sounds innocuous, but it has a radical implication: that the divisions between nature and society, matter and mind, biology and culture, and the sciences and the humanities, arts, and social sciences are as obsolete as the division between the sublunary and supralunary spheres.
For centuries, the progress of science has been a story of increasing consilience. The collapse of the wall between the terrestrial and celestial was followed by a collapse of the once equally firm (and now equally forgotten) wall between the past, when divine cataclysms were supposed to have shaped the earth, and the present, with its seemingly permanent mountains and oceans. Less than a century after Johnson, the geologist Sir Charles Lyell showed that today's Earth could have been sculpted by everyday erosion, earthquakes, and volcanoes acting in the past over immense spans of time. The living and nonliving, too, no longer occupy different realms. Two centuries before Lyell, physician William Harvey showed the human body to be a machine that uses hydraulics and other mechanical principles. Lyell's contemporary, the German chemist Friedrich Wöhler, showed with his synthesis of urea that the stuff of life is not a magical gel but ordinary compounds following the laws of chemistry. Charles Darwin showed how the astonishing diversity of life and its ubiquitous signs of design could arise from the physical process of the natural selection of replicators. Gregor Mendel, and then James D. Watson and Francis Crick, showed how replication itself could be understood in physical terms.
For Wilson, the final chasm that separates biology from the humanities will be bridged by an understanding of human nature that comes from neuroscience, psychology, and evolutionary biology. Human thoughts and feelings are patterns of activity of the brain, whose design is a product of natural selection. The brain was "engineered" as a dynamic neural computer that calculated the strategies of survival and reproduction needed by our evolutionary ancestors. As humans discovered things about their world and each other and shared these discoveries, and as they instituted conventions and rules to coordinate their desires, the phenomenon called "culture" arose.
Culture and society, then, are not autonomous forces but products of minds interacting with one another, and culture evolved along with the brain. Sociology and anthropology are the study of the products of the human tendency to form clans, partnerships, and coalitions. Economics ideally would be based on real human preferences and decision-making strategies (rather than the idealized "rational agent" assumed by economists today). Literature comes from people's obsession with universal life-and-death themes such as kinship, danger, and rivalry. Art depends on an innate eye for optimal habitats and forms, and on the biases of our visual systems. Morality comes from the sense of empathy and the internalized standards that allow people to live harmoniously in groups.
Science students often experience the exhilarating realization that the laws of the whole world fit together. Wilson refers to that blessed state as the Ionian Enchantment, after the 6th century B.C. founder of the physical sciences, Thales of Ionia. Like many scientists, Wilson had an Ionian Enchantment as a student, but Consilience comes from a second enchantment he experienced in the 1970s, when he was already an esteemed entomologist. (Click to see how he uses entomology--the ultimate multicultural curriculum--to open his readers' eyes to the dependence of human culture on human nature.) Evolutionary biologists had recently worked out the implications of Darwin's theory for the social lives of organisms. Former paradoxes of animal behavior such as cooperation, sexuality, aggression, pacifism, and communication were being increasingly understood in terms of the natural selection of genes. Wilson wrote a famous book in 1975 called Sociobiology: The New Synthesis, and he later extended it with bits of psychology and mathematical modeling to yield a theory he called "gene-culture coevolution."
Not everyone was enchanted. Angry critics charged that if the mind had an innate structure, different people (or classes, sexes, and races) could have different innate structures, justifying discrimination. They said that if obnoxious behaviors such as aggression and clannishness were innate, that would make them "natural" and hence good; or, even if bad, they would be "in the genes" and hence unchangeable, subverting hopes for social reform. They said that if behavior were caused mainly by the genes, individuals could not be held responsible for their actions. Some of these scholars expressed their disagreement by dousing Wilson with a pitcher of water at a scientific convention, yelling for his dismissal over bullhorns, urging people to bring noisemakers to his lectures, and publishing righteous manifestoes and sarcastic, book-length denunciations.
In fact, many of the accusations--for example, that he was really trying to justify male philandering--were simply preposterous, and others could be countered easily. Innate similarities do not imply innate differences. Genetically influenced behavior is not necessarily good and not necessarily unchangeable. Explanations of bad behavior that appeal to genes do not absolve a person any more than do explanations that appeal to upbringing.
L ife has been kinder to Wilson since then. He won two Pulitzers (for On Human Nature, 1978, and The Ants, 1990). His articulate advocacy of biodiversity and his graceful autobiography (Naturalist, 1994) changed his image in the popular press from bad guy to good guy. His insights on sociobiology, minus the inflammatory connotations, have become widely accepted in new fields such as behavioral ecology and evolutionary psychology.
The tide has turned so much that one might wonder whether Wilson needs to make such a fuss about the unity of knowledge. I can confirm he does, for I have tried to convey the same Ionian Enchantment in my recent book How the Mind Works. Anyone who thinks that consilience is banal or obvious is invited to read my debates with the sociologist Alan Wolfe in Slate and with the biologist Steven Rose in Edge. (Or click to read my summary of Wolfe's and Rose's positions.)