We may open the Critique of Pure Reason wherever we please, we shall always find that in all its discussions these two dogmatic propositions are taken for granted. Cohen [27] and Stadler [28] attempt to prove that Kant has established the a priori character of the propositions of Mathematics and Pure Natural Science. But all that Kant tries to do in the Critique may be summed up as follows. The fact that Mathematics and Pure Natural Science are a priori sciences implies that the "form" of all experience has its ground in the subject. Hence, all that is given by experience is the "matter" of sensations. This matter is synthesised by the forms, inherent in the mind, into the system of empirical science. It is only as principles of order for the matter of sense that the formal principles of the a priori theories have function and significance. They make empirical science possible, but they cannot transcend it. These formal principles are nothing but the synthetic judgments a priori, which therefore extend, as conditions of all possible empirical knowledge, as far as that knowledge but no further. Thus, the Critique of Pure Reason, so far from proving the a priori character of Mathematics and Pure Natural Science, does but delimit the sphere of their applicability on the assumption that their principles must become known independently of experience. Indeed, Kant is so far from attempting a proof of the a priori character of these principles, that he simply excludes that part of Mathematics (see the quotation above) in which, even according to his view, that character might be called in question, and confines himself to the part in which he thinks he can infer the a priori character from the bare concepts involved. Johannes Volkelt, too, comes to the conclusion that "Kant starts from the explicit presupposition" that "there actually does exist knowledge which is universal and necessary." He goes on to remark, "This presupposition which Kant has never explicitly questioned, is so profoundly contradictory to the character of a truly critical Theory of Knowledge, that the question must be seriously put whether the Critique is to be accepted as critical Theory of Knowledge at all." Volkelt does, indeed, decide that there are good grounds for answering this question in the affirmative, but still, as he says, "this dogmatic assumption does disturb the critical attitude of Kant's epistemology in the most far-reaching way." [29] In short, Volkelt, too, finds that the Critique of Pure Reason is not a Theory of Knowledge free from all assumptions. In substantial agreement with our view are also the views of O. Liebmann, [30] Holder, [31] Windelband, [32] Ueberweg, [33] Eduard von Hartmann, [34] and Kuno Fischer, [35] all of whom acknowledge that Kant makes the a priori character of Pure Mathematics and Physics the basis of his whole argumentation.