Whereas claims of human uniqueness used to revolve around the soul, they now revolve around the brain. Ever since Thomas Willis and his Oxford circle colleagues discovered in the late 1600s that the brain governs behavior, scientists have devoted considerable attention to this complex and inscrutable organ. Until recently, most approaches to the brain have been introspective and deductive. Philosophers and scientists traditionally have attempted to explain the brain's workings by examining its current functioning. They study, in other words, modern minds. While this top-down approach has yielded many insights, the limitations are obvious. To understand the human brain, a historical or evolutionary approach is necessary. It is only by locating the brain in deep time and tracing its evolutionary development that ...