But, let it be granted that we could discover, not in experience, but in certain firmly-established a priori laws of the use of pure reason—laws relating to our existence, authority to consider ourselves as legislating a priori in relation to our own existence and as determining this existence; we should, on this supposition, find ourselves possessed of a spontaneity, by which our actual existence would be determinable, without the aid of the conditions of empirical intuition. We should also become aware that in the consciousness of our existence there was an a priori content, which would serve to determine our own existence—an existence only sensuously determinable—relatively, however, to a certain internal faculty in relation to an intelligible world.
But this would not give the least help to the attempts of rational psychology. For this wonderful faculty, which the consciousness of the moral law in me reveals, would present me with a principle of the determination of my own existence which is purely intellectual—but by what predicates? By none other than those which are given in sensuous intuition. Thus I should find myself in the same position in rational psychology which I formerly occupied, that is to say, I should find myself still in need of sensuous intuitions, in order to give significance to my conceptions of substance and cause, by means of which alone I can possess a knowledge of myself: but these intuitions can never raise me above the sphere of experience. I should be justified, however, in applying these conceptions, in regard to their practical use, which is always directed to objects of experience —in conformity with their analogical significance when employed theoretically —to freedom and its subject. At the same time, I should understand by them merely the logical functions of subject and predicate, of principle and consequence, in conformity with which all actions are so determined, that they are capable of being explained along with the laws of nature, conformably to the categories of substance and cause, although they originate from a very different principle. We have made these observations for the purpose of guarding against misunderstanding, to which the doctrine of our intuition of self as a phenomenon is exposed. We shall have occasion to perceive their utility in the sequel.
