made the naïve assumption that sensibility was a kind of counter on which the external world deposited its wares, that so much of his philosophy is obsolete. Our desideratum is an analysis of the knowledge and experience we happen to possess, not an inquiry into the conditions of the universality and necessity of an imaginary possession which the rationalist asseverates we cannot, as men, be without.[1]
If we have a faculty that supplies us with knowledge without the aid of sense-experience, it is not unreasonable to suppose that it can also tell us a priori what its contributions are. And so Kant asserts that his theory of a priori knowledge is itself a priori. It is spun by reason out of its own resources. And it is absolutely complete and necessary. Reason, as the first preface declared, is an organic unity, so that " whatever it produces entirely out of itself, cannot hide itself, but is brought to light by reason itself." And in so bringing it to light the Critique gives a "perfectly complete" and "absolutely necessary" account, the very opposite of "opinion" or "hypothesis" which, according to the same preface, "in this kind of inquiries it is in no way permissible to propound." As its title at once indicates, The Critique of Pure Reason is an examination of the faculty of a priori cognitions by itself, without appeal to any kind of experience. It is a criticism of pure reason by pure reason. Its aim is to bring reason to a true knowledge of itself. For reason has hitherto misunderstood itself and fallen into self-contradiction. Kant will determine its limits with apodictic certainty, in accordance with immutable principles of its own institution. He can, therefore, boast that his system is "based on no data except the reason itself."[2] It excludes psychological reflection, which can give only empirical data. Kant repudiates such a method and procedure, and claims to prove everything " from absolutely certain principles a priori."[3] For pure reason contains in itself the "criterion (Richtschnur) for the criticism of its entire use."[4] What
