The author devotes a good number of pages to clarifying the relations between PHN, experimental psychology, and metaphysics. It is this thesis, a problem of the order of knowledge, that we wish to question. We shall first present some of the difficulties that give rise to the problem. Second, we shall indicate the kind of knowledge which PHN is. Third, we shall attempt to demonstrate that in the body of his work the kind of knowledge represented is that of the (...) "metaphysics of man" and not the "philosophy of human nature." Finally, we shall point out the importance, and non-verbal character, of a correct answer to the problem. (shrink)