If we propose to set forth the origin of these fundamental propositions and try to do so by the psychological method, we violate their sense. For they do not tell us what happens, _i.e._ by what rule our cognitive powers actually operate, and how we judge, but how we ought to judge; and this logical objective necessity does not emerge if the principles are merely empirical. Hence that purposiveness of nature for our cognitive faculties and their use, which is plainly apparent from them, is a transcendental principle of judgements, and needs therefore also a Transcendental Deduction, by means of which the ground for so judging must be sought in the sources of cognition _a priori_. We find in the grounds of the possibility of an experience in the very first place something necessary, viz. the universal laws without which nature in general (as an object of sense) cannot be thought; and these rest upon the Categories, applied to the formal conditions of all intuition possible for us, so far as it is also given _a priori_. Now under these laws the Judgement is determinant, for it has nothing to do but to subsume under given laws. For example, the Understanding says that every change has its cause (universal law of nature); the transcendental Judgement has nothing further to do than to supply _a priori_ the condition of subsumption under the concept of the Understanding placed before it, _i.e._ the succession [in time] of the determinations of one and the same thing. For nature in general (as an object of possible experience) that law is cognised as absolutely necessary.--But now the objects of empirical cognition are determined in many other ways than by that formal time-condition, or, at least as far as we can judge _a priori_, are determinable. Hence specifically different natures can be causes in an infinite variety of ways, as well as in virtue of what they have in common as belonging to nature in general; and each of these modes must (in accordance with the concept of a cause in general) have its rule, which is a law and therefore brings necessity with it, although we do not at all comprehend this necessity, in virtue of the constitution and the limitations of our cognitive faculties. We must therefore think in nature, in respect of its merely empirical laws, a possibility of infinitely various empirical laws, which are, as far as our insight goes, contingent (cannot be cognised _a priori_), and in respect of which we judge nature, according to empirical laws and the possibility of the unity of experience (as a system according to empirical laws), to be contingent. But such a unity must be necessarily presupposed and assumed, for otherwise there would be no thoroughgoing connexion of empirical cognitions in a whole of experience. The universal laws of nature no doubt furnish such a connexion of things according to their kind as things of nature in general, but not specifically, as such particular beings of nature.