On Ancient Medicine on the nature of human beings.

This paper discusses the theory of human nature (phusis) presented in On Ancient Medicine. In contrast to thinkers who claimed that medicine must be based on an account of the origin and development of human beings out of elemental constituents, the author of this treatise argues that the true foundation of medicine is knowledge of the humoral constitution of different individuals and of the interactions of the internal organs with fluids and air in the body. Such knowledge is limited in scope and can be attained only by reasoning from everyday experience and experience in medicine.