Book excerpt: One of the nation's leading neuroscientists presents a radically new view of the function of the brain and the nervous system. Its central idea is that the nervous system in each individual operates as a selective system resembling natural selection in evolution, but operating by different mechanisms. This far-ranging theory of brain functions is bound to stimulate renewed discussion of such philosophical issues as the mind-body problem, the origins of knowledge and the perceptual bases of language. Notes and Index.