thus, he does not intend to put them outside of religion; for it is in the essentially religious rites that he shows their action, for example, in the great Mexican ceremonies.[668] If he uses these expressions, it is undoubtedly because he knows no others which mark better the impersonality of these forces and the sort of mechanism with which they operate. Thus this same idea tends to come to light on every side.[669] The impression becomes more and more prevalent that even the most elementary mythological constructions are secondary products[670] which cover over a system of beliefs, at once simpler and more obscure, vaguer and more essential, which form the solid foundations upon which the religious systems are built. It is this primitive foundation which our analysis of totemism has enabled us to reach. The various writers whose studies we have just mentioned arrived at this conclusion only through facts taken from very diverse religions, some of which even correspond to a civilization that is already far advanced: such is the case, for example, with the Mexican religions, of which Preuss makes great use. So it might be asked if this theory is equally applicable to the most simple religions. But since it is impossible to go lower than totemism, we are not exposed to this risk of error, and at the same time, we have an opportunity of finding the initial notion from which the ideas of wakan and mana are derived: this is the notion of the totemic principle.[671] IV But this notion is not only of primary importance because of the rôle it has played in the development of religious ideas; it also has a lay aspect in which it is of interest for the history of scientific thought. It is the first form of the idea of force.