THIS BOOK has been written from a profound conviction that men engaged in the development of physical theory can profit from philosophical reflection about the meaning of their research, and that modern physics holds a message for philosophy. This latter argument is not a novel one, and in espousing it the author enters with some diffidence an arena that teems with gladiators of distinction. He should therefore state his challenge. It is that he believes the attitudes of uncritical realism, unadorned operationalism, and radical empiricism, which pervade most of the discussions and much of the thinking on subjects of science, to be outmoded and in disharmony with the successful phases of contemporary physics. He starts by analyzing all experience, not only the peripheral part called empirical knowledge in a narrow sense. He ends with an epistemology which is in keeping with both classical physics and the quantum theory, a philosophy of science which allows this reputedly heterodox new discipline, this breeding ground for paradoxes, to be seen as a culmination of methods long present in natural science.
Brief explanations of several features which are apt to evoke objections from the philosophic reader will be offered here. The early chapters of the book may seem needlessly discursive and may appear to deal with traditional philosophic problems which it is not wholly proper for scientists to raise. These chapters were nevertheless included not only because they prepare the way for the nonphilosophic reader, but more particularly because the later portions of the book will argue that "traditional" questions have greater relevance for science than is frequently believed. However, omission of the first three chapters will not preclude understanding of the book's main points.
An explanation should also be made for the occasional use of mathematics, albeit a very limited use. No major conclusions are drawn from purely mathematical arguments, and the reason-