The revelation of such an original fundamental activity of the spirit must induce us to undertake to form our whole world from this activity, and to produce from it or to transform into it that which exists over against activity as an independent realm of experience. This has been attempted for thousands of years with the summoning of an enormous amount of spiritual power and the arousing of a proud self-consciousness. But failure was inevitable because it was not recognised that the development of the spiritual life in man is conditioned. However certain it may be that original spiritual movements must be active within us, they are not so with organised content and overwhelming power from the beginning, but they acquire content and power only through the process of life itself, only in grappling with the oppositions of experience and in the appropriation of the tasks and stimuli which experience brings to them. The incompleteness and the mutability of what was accepted earlier as a fixed and unchangeable racial possession of the spiritual life is to-day quite clearly perceived. What great changes morality, for example, has undergone in the course of the ages; how toilsomely has much been won which later ages have considered self-evident! To be sure, morality remains, even through all such changes, an original spiritual phenomenon, which can never be derived from an external source, but which could emerge and establish itself only as an inner necessity of the spiritual life in opposition to the realm of mere utility. But the actuality of this original phenomenon gives rise to a difficult problem, for the solution of which a closer contact with the environment, a fundamental arrangement with experience, is necessary. And so the problem is traced to a more ultimate source, and, though this makes the matter less simple, it gives a higher significance to our work and to the movement of history. Even the fundamental forms of thought which are often accepted as of everything the most fixed share in this gradual amplification. Man, so far as he participates in spiritual impulse, thinks, of course, in conceptions; he gives to appearances fixed points of support by the establishing of things, and relates events causally. But all this is full of problems and is comprehended only in its upward endeavour; it raises more problems than it solves; and around the solution of these the whole work of science moves. What different things the "idea" meant to Plato and to Kant, and to ancient and to modern thought generally: how every thinker of moment has given a particular conception of substance and of causality; how whole epochs have exhibited their particular nature in the treatment of these problems!