The author proposes and elaborates a definition of philosophy and illustrates the relevance of this definition in the work of six philosophers whose writings have been crucial to the development of Western thought - Plato, Descartes, Hume, Kant, Husserl, and Heidegger. Professor Ballard defines philosophy as the interpretation of archaic experience - that transition or change which forces one to attempt to understand, and usually reformulate, the basic notional framework within which order and value are discovered. He traces the growth and various directions of Western thought, and speculates on the potential for its future development.