the perception out of which the conceptions are framed, in order to assure ourselves that our thought has still real content. This, however, necessarily presupposes that the conceptions which occupy us are sprung from perception, and it is merely a glance back at their material content, indeed a mere aid to our weakness. But in the case of a priori conceptions which as yet have no content at all, clearly this is necessarily omitted. For these conceptions are not sprung from perception, but come to it from within, in order to receive a content first from it. Thus they have as yet nothing on which they could look back. I speak fully upon this point, because it is just this that throws light upon the secret origin of the Kantian philosophising, which accordingly consists in this, that Kant, after the happy discovery of the two forms of intuition or perception a priori, exerted himself, under the guidance of the analogy, to prove that for every determination of our empirical knowledge there is an a priori analogue, and this finally extended, in the schemata, even to a mere psychological fact. Here the apparent depth and the difficulty of the exposition just serve to conceal from the reader that its content remains a wholly undemonstrable and merely arbitrary assumption. But he who has penetrated at last to the meaning of such an exposition is then easily induced to mistake this understanding so painfully attained for a conviction of the truth of the matter. If, on the contrary, Kant had kept himself here as unprejudiced and purely observant as in the discovery of a priori intuition or perception, he must have found that what is added to the pure intuition or perception of space and time, if an empirical perception arises from it, is on the one hand the sensation, and on the other hand the knowledge of causality, which changes the mere sensation into objective empirical perception, but just on this account is not first derived and learned from sensation, but exists a priori, and is indeed the form and function of the pure understanding. It is also, however,
