If, therefore, the Ideas are to become objects of knowledge, this can only happen by transcending the individuality of the knowing subject. The more exact and detailed explanation of this is what will now occupy our attention. § 31. First, however, the following very essential remark. I hope that in the preceding book I have succeeded in producing the conviction that what is called in the Kantian philosophy the _thing-in-itself_, and appears there as so significant, and yet so obscure and paradoxical a doctrine, and especially on account of the manner in which Kant introduced it as an inference from the caused to the cause, was considered a stumbling-stone, and, in fact, the weak side of his philosophy,—that this, I say, if it is reached by the entirely different way by which we have arrived at it, is nothing but the _will_ when the sphere of that conception is extended and defined in the way I have shown. I hope, further, that after what has been said there will be no hesitation in recognising the definite grades of the objectification of the will, which is the inner reality of the world, to be what Plato called the _eternal Ideas_ or unchangeable forms (ειδῆ); a doctrine which is regarded as the principal, but at the same time the most obscure and paradoxical dogma of his system, and has been the subject of reflection and controversy of ridicule and of reverence to so many and such differently endowed minds in the course of many centuries. If now the will is for us the _thing-in-itself_, and the Idea is the immediate objectivity of that will at a definite grade, we find that Kant’s thing-in-itself, and Plato’s Idea, which to him is the only οντως ον, these two great obscure paradoxes of the two greatest philosophers of the West are not indeed identical, but yet very closely related, and only distinguished by a single circumstance. The purport of these two great paradoxes, with all inner harmony and relationship, is yet so very different on account of the remarkable diversity of the individuality of their authors, that they are the best commentary on each other, for they are like two entirely different roads that conduct us to the same goal. This is easily made clear. What Kant says is in substance this:—“Time, space, and causality are not determinations of the thing-in-itself, but belong only to its phenomenal existence, for they are nothing but the forms of our knowledge. Since, however, all multiplicity, and all coming into being and passing away, are only possible through time, space, and causality, it follows that they also belong only to the phenomenon, not to the thing-in-itself. But as our knowledge is conditioned by these forms, the whole of experience is only knowledge of the phenomenon, not of the thing-in-itself; therefore its laws cannot be made valid for the thing-in-itself. This extends even to our own _ego_, and we know it only as phenomenon, and not according to what it may be in itself.” This is the