If, with Hume, I had removed the objective reality from the concept of causality in its theoretic use not only with regard to things in themselves (the suprasensible) but also with regard to objects of the senses, then the concept would have lost all signification and, as a theoretically impossible concept, would have been declared entirely unusable; and since one also can make no use of nothing, the practical use of a theoretically null concept would have been entirely absurd.