(_a._) The _hypothetical judgment_ in general is the abstract expression of that most universal form of all our knowledge, the principle of sufficient reason. In my essay on this principle, I already showed in 1813 that it has four entirely different meanings, and in each of these originally originates in a different faculty of knowledge, and also concerns a different class of ideas. It clearly follows from this, that the source of the hypothetical judgment in general, of that universal form of thought, cannot be, as Kant wishes to make it, merely the understanding and its category of causality; but that the law of causality which, according to my exposition, is the one form of knowledge of the pure understanding, is only one of the forms of that principle which embraces all pure or _a priori_ knowledge—the principle of sufficient reason—which, on the other hand, in each of its meanings has this hypothetical form of judgment as its expression. We see here, however, very distinctly how kinds of knowledge which are quite different in their origin and significance yet appear, if thought _in abstracto_ by the reason, in one and the same form of combination of concepts and judgments, and then in this form can no longer be distinguished, but, in order to distinguish them, we must go back to knowledge of perception, leaving abstract knowledge altogether. Therefore the path which was followed by Kant, starting from the point of view of abstract knowledge, to find the elements and the inmost spring of intuitive knowledge also, was quite a wrong one. For the rest, my whole introductory essay on the principle of sufficient reason is, to a certain extent, to be regarded merely as a thorough exposition of the significance of the hypothetical form of judgment; therefore I do not dwell upon it longer here.