them. How should it be otherwise, if psychology has for its object the study of the human mind working for practical utility, and if metaphysics is but this same mind striving to transcend the conditions of useful action and to come back to itself as to a pure creative energy? Many problems which appear foreign to each other as long as we are bound by the letter of the terms in which these two sciences state them, are seen to be very near akin and to be able to solve each other when we thus penetrate into their inner meaning. We little thought, at the beginning of our enquiry, that there could be any connexion between the analytical study of memory and the questions which are debated between realists and idealists, or between mechanists and dynamists, with regard to the existence or the essence of matter. Yet this connexion is real, it is even intimate; and, if we take it into account, a cardinal metaphysical problem is carried into the open field of observation, where it may be solved progressively, instead of for ever giving rise to fresh disputes of the schools within the closed lists of pure dialectic. The complexity of some parts of the present work is due to the inevitable dovetailing of problems which results from approaching philosophy in such a way. But through this complexity, which is due to the complexity of reality itself, we believe that the reader will find his way if he keeps a fast hold on the two principles which we have used as a clue throughout our own researches. The first
