George Roche, the thoughtful president of Hillsdale College, says it takes just two people to befuddle the theory of evolution: the man who leaps from a bridge to commit suicide, and the man who leaps off the bridge to save him. Neither action fits into the Darwinian scheme of things: If a human being's most basic drive is self-preservation and the replication of his genes, the first man wouldn't have jumped, but if he did, the second man wouldn't have risked his own life to save him. Bothersome things such as death-wishes and altruism are roadblocks for the scientists who are on a spiritual quest: the search for the Theory of Everything. Stephen Hawking has sought it; even Einstein was relatively sure it must be out there. In short, this Grand Theory would explain everything, fill in all the gaps in our understanding, and wrap up the universe in a tidy package. These are the thinkers, we should note, who call religion "fanciful." Consilience, by Harvard biologist Edward O. Wilson, is the latest attempt to fit everything together. His contribution to the Theory of Everything is an arranged marriage between the physical sciences and the social sciences. "Consilience," he says, is "literally a 'jumping together' of knowledge by the linking of facts and fact-based theory across disciplines to create a common groundwork of explanation." No longer will sociology and psychology be considered "soft" sciences, he predicts; as we learn more about the evolution of the brain, we will learn more about the chemical and genetic causes of human behavior. Soon everything will be reducible to the laws of physics. It promises to be a rocky marriage, however. Mr. Wilson is disdainful of his social-science bride: Its adherents, he says, "are easily shackled by tribal loyalty. Much of what passes for social theory is still in thrall to the original grand masters.... Consequently, too many social-science textbooks are a scandal of banality." (No kidding.) The real test of the marriage, Mr. Wilson writes, will be finding a way to stuff the arts into evolutionary theory. And he gives it a go, but with very limited success. He jumps from cave art to Milton's Paradise Lost and says they're essentially environmental metaphors, the "consequence of spreading activation of the brain during learning." He then optimistically concludes, "It follows that even the greatest works of art might be understood fundamentally with knowledge of the biologically evolved epigenetic rules that guided them." There is one very bright spot in this chapter, however. Mr. Wilson promises that biologists will someday-may it be soon!-trounce the postmodernists, since postmodernists dare say that science and truth are relative and personal. There is, of course, already a Theory of Everything. It has often been summed up, scientifically speaking, in the statement, "God saves sinners." If any one of those three little words is removed, then the universe becomes completely unfathomable. But taken together, they demonstrate true consilience.