principles which are not determinant, as they must be in Doctrine, it must constitute a special part of the Critique. On the other hand, the aesthetical Judgement contributes nothing towards the knowledge of its objects, and thus must be reckoned as belonging to the criticism of the judging subject and its cognitive faculties, _only_ so far as they are susceptible of _a priori_ principles, of whatever other use (theoretical or practical) they may be. This is the propaedeutic of all Philosophy. IX. OF THE CONNEXION OF THE LEGISLATION OF UNDERSTANDING WITH THAT OF REASON BY MEANS OF THE JUDGEMENT The Understanding legislates _a priori_ for nature as an Object of sense--for a theoretical knowledge of it in a possible experience. Reason legislates _a priori_ for freedom and its peculiar casuality; as the supersensible in the subject, for an unconditioned practical knowledge. The realm of the natural concept under the one legislation and that of the concept of freedom under the other are entirely removed from all mutual influence which they might have on one another (each according to its fundamental laws) by the great gulf that separates the supersensible from phenomena. The concept of freedom determines nothing in respect of the theoretical cognition of nature; and the natural concept determines nothing in respect of the practical laws of freedom. So far then it is not possible to throw a bridge from the one realm to the other. But although the determining grounds of causality according to the concept of freedom (and the practical rules which it contains) are not resident in nature, and the sensible cannot determine the supersensible in the subject, yet this is possible conversely (not, to be sure, in respect of the cognition of nature, but as regards the effects of the supersensible upon the sensible). This in fact is involved in the concept of a causality through freedom, the _effect_ of which is to take place in the world according to its formal laws. The word _cause_, of course, when used of the supersensible only signifies the _ground_ which determines the causality of natural things to an effect in accordance with their proper natural laws, although harmoniously with the formal principle of the laws of Reason. Although the possibility of this cannot be comprehended, yet the objection of a contradiction alleged to be found in it can be sufficiently answered.[10]--The effect in accordance with the concept of freedom is the final purpose which (or its phenomenon in the world of sense) ought to exist; and the condition of the possibility of this is presupposed in nature (in the nature of the subject as a sensible being, that is, as man). The Judgement presupposes this _a priori_ and without reference to the practical; and thus furnishes the mediating concept between the concepts of nature and that of freedom. It makes possible the transition from the conformity to law in accordance with