A New Demonstration.==
§ 15. Cases which are not comprised among the old established meanings of the Principle.
FROM the summary given in the preceding chapter we gather, that two distinct applications of the principle of sufficient reason have been recognized, although very gradually, very tardily, and not without frequent relapses into error and confusion: the one being its application to judgments, which, to be true, must have a reason; the other, its application to changes in material objects, which must always have a cause. In both cases we find the principle of sufficient reason authorizing us to ask why? a quality which is essential to it. But are all the cases in which it authorizes us to ask why comprised in these two relations? If I ask: Why are the three sides of this triangle equal? the answer is: Because the three angles are so. Now, is the equality of the angles the cause of the equality of the sides? No; for here we have to do with no change, consequently with no effect which must have a cause.—Is it merely a logical reason? No; for the equality of the angle is not only a proof of the equality of the sides, it is not only the foundation of a judgment: mere conceptions alone would never suffice to explain why the sides must be equal, because the angles are so; for the conception of the equality of the sides is not contained in that of the equality of the angles. Here therefore we
