It is Tylor who formed the animist theory in its essential outlines.[96] Spencer, who took it up after him, did not reproduce it without introducing certain modifications.[97] But in general the questions are posed by each in the same terms, and the solutions accepted are, with a single exception, identically the same. Therefore we can unite these two doctrines in the exposition which follows, if we mark, at the proper moment, the place where the two diverge from one another.
In order to find the elementary form of the religious life in these animistic beliefs and practices, three _desiderata_ must be satisfied: first, since according to this hypothesis, the idea of the soul is the cardinal idea of religion, it must be shown how this is formed without taking any of its elements from an anterior religion; secondly, it must be made clear how souls become the object of a cult and are transformed into spirits; and thirdly and finally, since the cult of these spirits is not all of any religion, it remains to be explained how the cult of nature is derived from it.
According to this theory, the idea of the soul was first suggested to men by the badly understood spectacle of the double life they ordinarily lead, on the one hand, when awake, on the other, when asleep. In fact, for the savage,[98] the mental representations which he has while awake and those of his dreams are said to be of the same value: he objectifies the second like the first, that is to say, that he sees in them the images of external objects whose appearance they more or less accurately reproduce. So when he dreams that he has visited a distant country, he believes that he really was there. But he could not have gone there, unless two beings exist within him: the one, his body, which has remained lying on the ground and which he finds in the same position on awakening; the other, during this time, has travelled through space. Similarly, if he seems to talk with one of his companions who he knows was really at a distance, he concludes that the other also is composed of two beings: one which sleeps at a distance, and another which has come to manifest himself by means of the dream. From these repeated experiences, he little by little arrives at the idea that each of us has a double, another self, which in determined conditions has the power of leaving the organism where it resides and of going roaming at a distance.