We have now reached a point where it will be possible in a few sentences to indicate the rise of the metaphysical reflection and the ground on which it rests. If we consider both the mathematical and the physical ways of looking at things, we will find that they possess this feature in common,--they are purely external, having nothing to say respecting the _inner_ and, therefore, _real_ nature of the things with which they deal. Or, if we concede the latest claims of some of the physical speculators and agree that the aim of physics is an ultimate physical explanation of reality, it will still be true that the whole standpoint of this explanation will be external. Let me explain briefly what I mean substantially by the term _external_ as I use it here. Every interpretation of a world is a function of some knowing consciousness, and consequently of some knowing self. This is too obvious to need proof. A system will be _external_ to such a knower just to the extent that the knower finds it dominated and determined by categories that are different from those of its own determination. A world physically interpreted is one that is brought completely under the rubrics of physics and mathematics; whose movements yield themselves completely, therefore, to a mechanical calculus that gives rise to purely descriptive formulæ; _or_ to the control of a dynamic principle; that of natural causation, by virtue of which everything is determined without thought of its own, by the impulse of another, which impulse itself is not directly traceable to any thought or purpose. Now, the occasion for the metaphysical reflection arises when this situation that brings us face to face, with, nay, makes us part and parcel of, an alien system of things, becomes intolerable, and the knower begins to demand a closer kinship with his world. The knower finds the categories of his own central and characteristic activity in experience. Here he is conscious of being an agent going out in forms of activity for the realization of his world. The determining categories of the activity he is most fully conscious of, are interest, idea, prevision, purpose, and that selective activity which goes to its termination in some achieved end. The metaphysical interpretation arises out of the demand that the world shall be brought into bonds of kinship with the knower. And this is effected by generalizing the categories of consciousness and applying them as principles of interpretation to the world. The act of reflection on which the metaphysical interpretation proceeds is one, then, in which the world of science is further transformed by bringing the inner nature of things out of its isolation and translating the world-movements into process the terms of which are no longer _phenomena and hidden ground_, but rather inception and realization, or, more specifically, _Idea_ and _Reality_. And the point to be noted here is the fact that these