This postulate, according to Comte, is sufficiently established by biology, by means of the comparative method. All the principal characteristics which pride and ignorance set up as absolute privileges of our species, also appear, more or less rudimentary, in the majority of the higher animals.[205] The mistake was made because metaphysical ideology and psychology place intelligence foremost in the study of psychical functions. Intelligence indeed puts to-day an immense distance between man and animals. But a more accurate psychology recognises that the most energetic, the most “fundamental” of mental functions are the affective functions, since, in default of the impulse given by them, intelligence itself would not be developed. The analogy between man and the animals at once appears: for the affective functions are common to them both. It is the same with the intellectual functions, when allowance is made for the development they have assumed in man. In a word, if the dynamical superiority of the human species over the other species is strong, its statical superiority is weak. The problem consists in finding how, to such an apparently unimportant difference in the organs, such a considerable difference in the functions corresponds.[206] Here comes in the second postulate: “The fundamental constitution of man is invariable.” _Evolution but not transformation_: this great principle, transmitted by biology to sociology, dominates the latter science entirely. In the course of the long history which leads humanity from savage animality to positive civilisation,[207] nothing absolutely new appears. Everything which manifests itself little by little, pre-existed in the nature of man--in a potential state it is true; and this state would perhaps never have ceased if a number of favourable conditions had not occurred together.