A long history of inquiry about human nature and the self stretches from the ancient tradition of Socratic self-knowledge in the context of ethical life to contemporary discussions of brain function in cognitive science. It begins with a conflict among the ancients. On one view, which comes to be represented most clearly by Aristotle, the issue is settled in terms of a composite and very complex human nature. Who I am is closely tied to my embodied existence. The other view, found as early as the Pythagoreans, and developed in the writings of Plato, Augustine and Descartes, held that genuine humanness is not the result of an integration of 'lower' functions, but a purification of those functions in favour of a liberating spirituality. The animal elements are excluded from the human essence. The modern debate on the problem of the self, although owing much to the insights of Locke and Hume, can still be situated within the context of the two schools of ancient thought.