The slightest self-observation must show every one a remarkable difference between the various immediate conditions of his consciousness, which we may also call representations. For some of them appear altogether dependent upon our freedom, and we cannot possibly believe that there is without us anything corresponding to them. Our imagination, our will, appears to us as free. Others, however, we refer to a Truth as their model, which is held to be firmly fixed, independent of us; and in determining such representations, we find ourselves conditioned by the necessity of their harmony with this Truth. In the knowledge of them we do not consider ourselves free, as far as their contents are concerned. In short: while some of our representations are accompanied by the feeling of freedom, others are accompanied by the feeling of necessity. Reasonably the question cannot arise—why are the representations dependent upon our freedom determined in precisely this manner, and not otherwise? For in supposing them to be dependent upon our freedom, all application of the conception of a ground is rejected; they are thus, because I so fashioned them, and if I had fashioned them differently, they would be otherwise. But it is certainly a question worthy of reflection—what is the ground of the system of those representations which are accompanied by the feeling of necessity and of that feeling of necessity itself? To answer this question is the object of philosophy; and, in my opinion, nothing is philosophy but the Science which solves this problem. The system of those representations, which are accompanied by the feeling of necessity, is also called _Experience_—internal as well as external experience. Philosophy, therefore, to say the same thing in other words, has to find the ground of all Experience.