People have been tryi~g to explain the emergence of new concepts for over two thousand years. Writers of almost every kind have been at one time or another concerned with it: philosophers, theologians, psychologists, physical scientists, poets. The history of their theories ranges from Plato to Saint Augustine, from Bacon and Descartes to Hartley, Hobbes, Locke, and Hume; from the Romantic poets of the nineteenth century to Bergson, Freud, and the Gestalt psychologists. In our own time the body of literature on the subject has reached epic proportions. American industry, for its own reasons, has developed a kind of manic preoccupation with the subject and many writers from the academic world, largely in one or another of the social sciences, have reflected industry's concern.