Errors of interpretation are very often due to a lack of historical perspective. Once they have been formulated and adopted by current opinion they are difficult to rectify. Time is needed in order that beneath superficial differences, deep seated resemblances may appear. During many years Kant was in all sincerity looked upon as a sceptic in France. Those who criticised him could not conceive how any one could give up metaphysical dogmatism, without at the same time abandoning the doctrines which had been cast in the metaphysical form before Kant. In the same way, in the eyes of most of his adversaries, Comte’s system must have appeared as the very negation of philosophy, because the terms “philosophy” and “relative” seemed incompatible to them. But this system, which is an effort to realise, from the point of view of positive science, the unity of the understanding, and the “perfect logical coherence,” in reality ends by putting the traditional problems of philosophy in a form suitable to the spirit of our age. IV. If the relationship between Comte’s philosophy and the doctrines which preceded it is sufficiently evident, it does not follow that this philosophy has brought with it nothing new. On the contrary, the “transposition” of problems and the constant effort to substitute the relative to the absolute point of view, entails serious consequences with very far reaching effects. Some of these were at once apparent, and first served to characterise positive philosophy in the eyes of the public. Others, more remote, but no less important, appeared more slowly. The negative consequences almost alone attracted attention at first. The chief characteristic of the new philosophy seemed to be the denial of the legitimacy and even of the possibility of metaphysics in all its forms: rational psychology, the philosophical theory of matter and of life, rational theology, etc. It seemed also to deny the possibility of introspective psychology, of ethics in its traditional form, as well as of logic. In a word, one after another, it excluded all the parts of what constituted a “course of philosophy.” No wonder, then, if this doctrine which took the name of “positive” appeared to be chiefly negative. However, in reality, the negation only affected the so-called “rational” or “philosophical sciences.” Comte reproached them with what Aristotle calls τὸ κένως ζητεῖν. Stringently applying the principle of the relativity of knowledge, he refused to admit anything absolute. He was therefore perfectly true to himself in rejecting doctrines founded upon metaphysical principles. But this entirely negative aspect of his philosophy is very far from being the one according to which we can best understand it. Truly speaking, it is only preparatory, and historians have often committed the mistake of allowing people to believe that it is essential. “_We only destroy what we replace_,” said Comte.