With respect to the references given at the end of the several chapters, I may note that their aim is simply to afford the reader some preliminary guidance in the further prosecution of his studies. They make no pretence to completeness, and are by no means exclusively drawn from writers who support my own conclusions. One or two important works of which I should have otherwise been glad to make extended use have appeared too recently for me to avail myself of them. I may mention especially the late Professor Adamson’s _Lectures on the Development of Modern Philosophy_, Professor Ostwald’s _Vorlesungen über Naturphilosophie_, and Mr. B. Russell’s _Principles of Mathematics_, vol. 1. Finally, I have to express my gratitude to my friends Professor S. Alexander and Mr. P. J. Hartog for their kindness in reading large portions of my proofs and offering many valuable corrections and suggestions. 1903 -------------- The sudden demand for a re-issue of this volume prevents my making any alterations beyond the correction of a number of misprints. Had the opportunity offered, I should have been glad, while leaving the main argument essentially as it stands, to have attempted certain improvements in details. I may mention in particular, as the most important of the changes I could have wished to make, that the treatment of the problem of infinite regress and of the Kantian antinomies would have been remodelled, and I trust improved, as a consequence of study of the works of Mr. Bertrand Russell and M. Couturat. I should like to take this opportunity of thanking all those who have been kind enough to favour me with criticisms of the book. CONTENTS BOOK I GENERAL NOTIONS CHAPTER I THE PROBLEM OF THE METAPHYSICIAN PAGE