The relationship between mind and matter has eluded and puzzled philosophers and scientists since the earliest times. In this book, a distinguished scientist reminds his readers of some of the paradoxes of this relationship, and offers his own suggestions towards a solution of the problem. He asks what place consciousness occupies in the evolution of life, and what part the state of development of the human mind plays in moral questions. He shows that the biological evidence, while apparently against any systematic increase in man's intellectual powers from one generation to another, is on closer inspection favorable, provided certain conditions are fulfilled. Another problem, that of the lack of sensible quantities (color, warmth, sound) in the scientist's picture of the world is, he suggests, created by the rigid distinctions made in Western thought between subject and object. Is there in fact one real world external to our perceptions? Or is this question itself misleading? Experience after all tells us nothing of the world beyond our senses. Science, similarly, tell us nothing of values; a personal God cannot form part of the space-time picture. But indirectly (for example) Plato, Kant and Einstein, in modifying our conception of time, have helped us with the question of survival. Readers of Professor Schrödinger's other popular scientific works will here find the same clear and sensitive treatment of one of the most difficult of intellectual problems.