REVIEWS OF BOOKS.
This book is a welcome sequel to the author's Enquiry concerning the Principles of Natural Knowledge, and it goes far toward realising the ideal of a comprehensive philosophy of nature. The electro-magnetic theory of relativity, which has met with such a favorable reception among the physicists and mathematicians, certainly involves a new philosophy of nature, but most of the students of that theory have naturally been more interested in the scientific revolution it carries with it, than in its philosophical implications. It is fortunate that a person so well equipped from the side of mathematics and physics as Professor Whitehead is, should set himself the task of working out the philosophy of nature required by the theory. Professor Whitehead has evidently read widely and profoundly in recent philosophy, and the results are seen in almost every page of this work. It is therefore inevitable that a book from such an author, who comes as near as it is possible to come to combining knowledge of scientific detail with that of mathematical and philosophical theory, should be of the greatest importance. Whether the view he presents proves to be ultimately acceptable or not, it will form the starting point for subsequent labors in the field, and in this sense, the work is epoch-making.
Such a work is impossible to outline in a short review. I shall therefore not attempt to give to those who have not read it an idea of what it contains. I shall rather pick out some points for discussion, assuming that those who read this review have already read the book. Professor Whitehead frankly declines to go into the metaphysical aspects of the problem, and he does not discuss epistemological questions. He merely assumes the existence of knowledge, as indeed he has the right to do, without inquiring why knowledge should be. In fact, he says that the question as to the why of knowledge is insoluble this is of course an epistemological position; but it is not argued. He says: "We are endeavoring in these lectures to limit ourselves to nature itself, and not to travel beyond entities which are disclosed in sense-awareness. Percipience itself is taken for granted. We consider indeed conditions for percipience, but only so far as those conditions
