Now, higher biology which deals with moral and intellectual phenomena, has only just been founded by Cabanis and Gall. Comte discovered that it could not be constituted as a science without the help of sociology. It is then to this newly born study that the search after intellectual laws in every way belongs. Positive logic abstains, as we see, from speculating upon the leading principles of knowledge, principles of identity, of contradiction of causality, etc. These kinds of principles are not objects of examination or of discussion. Comte upon this point is in full accord with the Scottish school. No positive science questions its own principles, for how can we submit the very principles of all reasoning to criticism? Nothing is less in accordance with the positive spirit than an attempt of this kind. It is simply metaphysical and has no chance of success. The intellectual laws of which the research is positive are such as the law of the three states (which is the most general of all), or such, for instance, as these: the human mind always makes an effort to place its conceptions in accordance with its observations; in every case the human mind forms the simplest hypothesis, etc. These laws, which are derived from the nature of the human mind, and whose action has always been felt, could only be discovered and formulated quite recently. For biology and sociology, to which they are related, could not be constituted before the more simple fundamental sciences were sufficiently advanced. To reach a scientific knowledge of the intellectual laws, to found a “positive logic,” nothing less was needed than the long evolution whose term is marked by Comte’s philosophy. Applied logic, or theory of method, also finds a new meaning in the positive doctrine. Comte does not fall into the mistake which he has criticised. He does not propose to teach an art _ex professo_, and he will not formulate the rules which positive research must follow in order to be productive. Here again Comte will found his doctrine upon the intellectual evolution of humanity.