In speaking of the transcendental fact, it must not be supposed that I allude to certain well-known _a priori_ speculations, which are opposed to my temper of mind and to my mode of teaching. I only use the term transcendental because this is actually the primitive condition of the fact in its inevitable beginning, whatever form the mythical representation may subsequently take. This fact is not peculiar to any individual, people, or race, but it is manifested as an essential organism of the human character, which is in all cases universal, permanent, and uniform.
In order to give a clear explanation of my estimate of the _a priori_ idea, which also takes its place as the factor of experimental and positive teaching, I must observe that for those who belong to the historical and evolutionary school, _a priori_, so far as respects any organism, habit, and psychological constitution in the whole animal kingdom, in which man is also included, signifies whatever in them is fixed and permanently organized; whatever is perpetuated by the indefinite repetition of habits, organs, and functions, by means of the heredity of ages. The whole history of organisms abounds with positive and repeated proofs of this fact, which no one can doubt who is not absolutely ignorant of elementary science. Every day adds to the number of these proofs, demonstrating one of those truths which become the common property of nations.
_A priori_ is therefore reduced by us to the modification of organs in their physical and psychical constitution, as it has ultimately taken place in the organism by the successive evolutions of forms which have gradually become permanent, and are perpetuated by embryogenic reproduction. This reproduction is in its turn the absolute condition of psychical and organic facts, which are thus manifested as primitive facts in the new life of the individual. By this law, the psychical facts, whether elementary or complex, as they occur in the individual up to the point of their evolution, have the necessary conditions of possibility, and may therefore be termed a _priori_ with respect to the laws of evolution, and to the hereditary permanence of acts performed in the former environment of the organism at the time when they appeared.