[100] Pol. pos., I. 447. [101] Pol. pos., II. 101-2. BOOK II THE PHILOSOPHY OF THE SCIENCES INTRODUCTION The Philosophy of the Sciences is one of the leading parts of Comte’s work. No other brings out more clearly the essential differences which distinguish his doctrine from previous systems. In Comte’s eyes the philosophy of the sciences is inseparable from the philosophy of history and from the theory of progress. For the sciences are great sociological facts and, as such, are subject, in their evolution, to invariable laws. The method of the philosophy of the sciences could therefore only be the positive method, ever like to itself. Moreover,--and this is an immediate consequence of this first consideration,--the object of the positive philosophy of the sciences is in no way to “explain” what the sciences themselves do not explain. The sciences, as is well known, do not inquire into their data and their principles. They consider them as sufficiently established by the implicit consent of all men, or at least by the universal usage of learned men. The geometer leaves to others the care of speculating upon the essence of space, or upon the _a priori_ character of his definitions. The physicist, if he form an idea of matter for himself, unhesitatingly adopts the one which appears to be the most immediately advantageous, that is to say, the one which is best in accordance with what he knows of its properties and of its laws. He attributes no more value than that of a simple hypothesis to this idea. Up to the present the business of solving the questions which the scientific man does not examine has belonged to the philosopher--understand by this term the metaphysician. It is for him to seek what matter, time, movement, space, etc., may be “in themselves.” Whether he descends from metaphysics to the positive sciences, or ascends from the latter to metaphysics, he always endeavours to show that such and such a transcendental hypothesis is more in accordance than any other with what we know to-day of the laws of nature. In a word; the philosophy of the sciences has been, in general, an effort to interpret scientific knowledge metaphysically. This explanation remains in respect to such a knowledge an “extrinsic denomination.” It explains but does not touch it. Now, according to Comte, there are not two forms of knowledge, the one positive and properly speaking scientific the other metaphysical and properly called philosophical. _The whole_ of our real knowledge in the end bears upon special or general facts. There can therefore be no question of a philosophy which should be essentially distinct from positive knowledge. Any attempt to explain by essences, causes, principles or ends, is excluded by the positive method. Metaphysical problems can no longer be set and, in this sense, when they disappear, the philosophy of the sciences disappears with them.