constitutes the forms of our intellect; indeed, this is less an explanation than merely the distinct expression of the fact itself. For a priori means nothing else than "not gained on the path of experience, thus not come into us from without." But what is present in the intellect, and has not come from without, is just what belongs originally to the intellect itself, its own nature. Now if what is thus present in the intellect itself consists of the general mode or manner in which it must present all its objects to itself, this is just saying that what is thus present is the intellect's forms of knowing, i.e., the mode, fixed once for all, in which it fulfils this its function. Accordingly, "knowledge a priori" and "the intellect's own forms" are at bottom only two expressions for the same things thus to a certain extent synonyms.
Therefore from the doctrine of the Transcendental Æsthetic I knew of nothing to take away, only of something to add. Kant did not carry out his thought to the end, especially in this respect, that he did not reject Euclid's whole method of demonstration, even after having said on p. 87; V. 120, that all geometrical knowledge has direct evidence from perception. It is most remarkable that one of Kant's opponents, and indeed the acutest of them, G. E. Schulze (Kritik der theoretischen Philosophie, ii. 241), draws the conclusion that from his doctrine an entirely different treatment of geometry from that which is actually in use would arise; and thus he thought to bring an apagogical argument against Kant, but, in fact, without knowing it, he only began the war against the method of Euclid. Let me refer to § 15 of the first book of this work.
After the full exposition of the universal forms of perception given in the Transcendental Æsthetic, one necessarily expects to receive some explanation as to its content, as to the way in which the empirical perception comes into our consciousness, how the knowledge of this whole world, which is for us so real and so important, arises in
