Of the prospect of progress in philosophy, it would be rash to speak with confidence. Many of the traditional problems of philosophy, perhaps most of those which have interested a wider circle than that of technical students, do not appear to be soluble by scientific methods. Just as astronomy lost much of its human interest when it ceased to be astrology, so philosophy must lose in attractiveness as it grows less prodigal of promises. But to the large and still growing body of men engaged in the pursuit of science--men who hitherto, not without justification, have turned aside from philosophy with a certain contempt--the new method, successful already in such time-honoured problems as number, infinity, continuity, space and time, should make an appeal which the older methods have wholly failed to make. Physics, with its principle of relativity and its revolutionary investigations into the nature of matter, is feeling the need for that kind of novelty in fundamental hypotheses which scientific philosophy aims at facilitating. The one and only condition, I believe, which is necessary in order to secure for philosophy in the near future an achievement surpassing all that has hitherto been accomplished by philosophers, is the creation of a school of men with scientific training and philosophical interests, unhampered by the traditions of the past, and not misled by the literary methods of those who copy the ancients in all except their merits. INDEX Absolute, 6, 39. Abstraction, principle of, 42, 124 ff. Achilles, Zeno's argument of, 173. Acquaintance, 25, 144. Activity, 224 ff. Allman, 161 n. Analysis, 185, 204, 211, 241. legitimacy of, 150. Anaximander, 3. Antinomies, Kant's, 155 ff. Aquinas, 10. Aristotle, 40, 160 n., 161 ff., 240. Arrow, Zeno's argument of, 173. Assertion, 52. Atomism, logical, 4. Atomists, 160. Belief, 58. primitive and derivative, 69 ff. Bergson, 4, 11, 13, 20 ff., 137, 138, 150, 158, 165, 174, 178, 229 ff. Berkeley, 63, 64, 102. Bolzano, 165. Boole, 40. Bradley, 6, 39, 165. Broad, 172 n. Brochard, 169 n. Burnet, 19 n., 160 n., 161 n., 170 n., 171 ff. Calderon, 95. Cantor, vi, vii, 155, 165, 190, 194, 199. Categories, 38. Causal laws, 109, 212 ff. evidence for, 216 ff. in psychology, 219. Causation, 34 ff., 79, 212 ff. law of, 221. not _a priori_, 223, 232. Cause, 220, 223. Certainty, degrees of, 67, 68, 212. Change, demands analysis, 151. Cinematograph, 148, 174. Classes, 202. non-existence of, 205 ff. Classical tradition, 3 ff., 58. Complexity, 145, 157 ff. Compulsion, 229, 233 ff. Congruence, 195. Consecutiveness, 134. Conservation, 105. Constituents of facts, 51, 145. Construction _v._ inference, iv. Contemporaries, initial, 119, 120 n. Continuity, 64, 129 ff., 141 ff., 155 ff. of change, 106, 108, 130 ff.