Page:Philosophical Review Volume 2.djvu/156

142 and intelligible abstract, it seems impossible to accept an interpretation of the critical problem which, whatever of truth it may contain, has the fatal defect of differing from the explicit statement of it there made by Kant himself.

The same caution is enjoined upon us by the history of Kant's philosophic development. Experiential knowledge, it might easily be shown, never made any difficulty for him. His perplexity began and ended with rational knowledge. That sensuous impressions should give us reports of their objects, he found natural enough. But how assertions made by reason alone should yet be true of objects: that was his great puzzle from 1772 to the completion of the Critique.

Yet in solving the question of a priori synthetic judgments, which remains Kant's central problem, he was brought to a view of experience from which it could no longer be regarded as the opposite of reason, as a simple, self-explaining or ultimate something accounting for a posteriori synthetic judgments, a thing of absolute indifference to the critical philosopher. On the contrary, experience became a matter of vital concern in the determination of the conditions of a priori knowledge. Mathematics, it is true, forms a special domain by itself, and the explanation of its possibility made no reference to experience. But when you ask how an a priori knowledge of nature is possible, you touch an object of which we have also an empirical knowledge. For what, in fact, is nature but the complex of all the objects of experience? Your problem, then, is to explain the possibility of an a priori. knowledge of objects of experience, such, for instance, as we have in the propositions, substance is permanent, and every event is determined by a cause. And if your solution is to the effect that nature, to be known thus a priori, must, though given to us through the senses, yet be subject to mind-imposed conditions, you cannot escape the conclusion that these are mixed up with sense-presentations in our a posteriori knowledge, so as, in fact, to form its constitutive principles, or, in Kant's phrase, to render experience possible. Thus, unintentionally and perhaps unwittingly, you have been forced to