First published in 1931 and originally delivered as the Deems Lectures at New York University in 1929, this book examines what scientific discoveries in many different branches of science reveal, and the implications of such discoveries for philosophy. Esteemed philosopher F. S. C. Northrop surveys a variety of advances, including relativity and quantum mechanics, and how they correlate to his epistemological theory of concepts. This book will be of value to anyone with an interest in the history of science and the connection between science and philosophy.