These two theories are, up to the present, the only ones by which the attempt has been made to explain rationally[93] the origins of religious thought. Thus the capital problem raised by the history of religions is generally reduced to asking which of these two solutions should be chosen, or whether it is not better to combine them, and in that case, what place must be given to each of the two elements.[94] Even those scholars who do not admit either of these hypotheses in their systematic form, do not refuse to retain certain propositions upon which they rest.[95] Thus we have a certain number of theories already made, which must be submitted to criticism before we take up the study of the facts for ourselves. It will be better understood how indispensable it is to attempt a new one, when we have seen the insufficiency of these traditional conceptions. I 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.