Without entering into the details of this religious construction we see that, like the ethics and the politics, it depends upon the “perfect mental coherence” founded, in the first place, by positive philosophy. In its turn, this perfect mental coherence, reduces itself to the unity of the understanding, whose necessary and sufficient conditions are “homogeneity of doctrine and unity of method.” Now, when Comte began to write, this homogeneity and this unity already existed for all the categories of natural phenomena. The moral and social phenomena alone were still an exception. In conclusion everything was reduced to this question: “can moral and social facts be studied in the same way as the other natural phenomena?” If not, we must be resigned to the indefinite duration of the disorder of minds, and consequently of the disorder of customs and institutions. But, if the contrary is true, then the human understanding reaches the unity to which it aspires. Is sociology impossible? then we have no politics and no religion. Is sociology founded? then all the rest is based upon it. Thus, the creation of social science is the decisive moment in Comte’s philosophy. Everything starts from it and comes back to it. As in Platonism, all paths lead to the theory of ideas, so, from all the avenues of positivism we see sociology. Here, as in a common centre, are joined the philosophy of the sciences, the theory of knowledge, the philosophy of history, psychology, ethics, politics and religion. Here, in a word, is realised the unity of system, a unity which, in Comte’s eyes, is the best proof of its truth. If, in sociology, we chiefly consider the end which Comte proposes to attain by its means, it is true that this doctrine is principally a political one, and the very title of Comte’s second great work bears this out. But, considered in itself, it is essentially a speculative effort, and the principle of a philosophy in the proper sense of the term. What Kant called a totality of experience is made possible by the creation of social science. Before Comte, this totality had been attempted many times. But those who attempted it started from this postulate that philosophy is specifically distinct from scientific knowledge proper. Whether philosophy were dogmatic or critical, whether it had bearings upon the essence of things or rather upon the laws of the mind, it none the less presented characteristics of its own, which seemed to separate it from positive science, and even allowed it to dominate over this science, and to “explain” its principles. Comte rejects this postulate. He is going to endeavour to see if, by taking the contrary postulate as his foundation, he will not succeed better than his predecessors.