But besides (to judge by analogy) there is a new ground for bringing the Judgement into connexion with another arrangement of our representative faculties, which seems to be of even greater importance than that of its relationship with the family of the cognitive faculties. For all faculties or capacities of the soul can be reduced to three, which cannot be any further derived from one common ground: the _faculty of knowledge_, the _feeling of pleasure and pain_, and the _faculty of desire_.[9] For the faculty of knowledge the Understanding is alone legislative, if (as must happen when it is considered by itself without confusion with the faculty of desire) this faculty is referred to nature as the faculty of _theoretical knowledge_; for in respect of nature (as phenomenon) it is alone possible for us to give laws by means of natural concepts _a priori_, _i.e._ by pure concepts of Understanding.--For the faculty of desire, as a higher faculty according to the concept of freedom, the Reason (in which alone this concept has a place) is alone _a priori_ legislative.--Now between the faculties of knowledge and desire there is the feeling of pleasure, just as the Judgement is intermediate between the Understanding and the Reason. We may therefore suppose provisionally that the Judgement likewise contains in itself an _a priori_ principle. And as pleasure or pain is necessarily combined with the faculty of desire (either preceding this principle as in the lower desires, or following it as in the higher, when the desire is determined by the moral law), we may also suppose that the Judgement will bring about a transition from the pure faculty of knowledge, the realm of natural concepts, to the realm of the concept of freedom, just as in its logical use it makes possible the transition from Understanding to Reason. Although, then, Philosophy can be divided only into two main parts, the theoretical and the practical, and although all that we may be able to say of the special principles of Judgement must be counted as belonging in it to the theoretical part, _i.e._ to rational cognition in accordance with natural concepts; yet the Critique of pure Reason, which must decide all this, as regards the possibility of the system before undertaking it, consists of three parts; the Critique of pure Understanding, of pure Judgement, and of pure Reason, which faculties are called pure because they are legislative _a priori_. IV. OF JUDGEMENT AS A FACULTY LEGISLATING _A PRIORI_