The actuality of a highest morally-legislating Author is therefore sufficiently established merely _for the practical use_ of our Reason, without determining anything theoretically as regards its being. For Reason requires, in respect of the possibility of its purpose, which is given to us independently by its own legislation, an Idea through which the inability to follow up this purpose, according to the mere natural concepts of the world, is removed (sufficiently for the reflective Judgement). Thus this Idea gains practical reality, although all means of creating such for it in a theoretical point of view, for the explanation of nature and determination of the supreme Cause, are entirely wanting for speculative cognition. For the theoretical reflective Judgement physical Teleology sufficiently proves from the purposes of nature an intelligent World-Cause; for the practical Judgement moral Teleology establishes it by the concept of a final purpose, which it is forced to ascribe to creation in a practical point of view. The objective reality of the Idea of God, as moral Author of the world, cannot, it is true, be established by physical purposes _alone_. But nevertheless, if the cognition of these purposes is combined with that of the moral purpose, they are, by virtue of the maxim of pure Reason which bids us seek unity of principles so far as is possible, of great importance for the practical reality of that Idea, by bringing in the reality which it has for the Judgement in a theoretical point of view.