Thus all tends to show that, in spite of the credit it still enjoys, the animistic theory of the soul must be revised. It is true that to-day the primitive attributes his dreams, or at least certain of them, to displacements of his double. But that does not say that the dream actually furnished the materials out of which the idea of the double or the soul was first constructed; it might have been applied afterwards to the phenomena of dreams, ecstasy and possession, without having been derived from them. It is very frequent that, after it has been formed, an idea is employed to co-ordinate or illuminate--with a light frequently more apparent than real--certain facts with which it had no relation at first, and which would never have suggested it themselves. God and the immortality of the soul are frequently proven to-day by showing that these beliefs are implied in the fundamental principles of morality; as a matter of fact, they have quite another origin. The history of religious thought could furnish numerous examples of these retrospective justifications, which can teach us nothing of the way in which the ideas were formed, nor of the elements out of which they are composed.
It is also probable that the primitive distinguishes between his dreams, and does not interpret them all in the same way. In our European societies the still numerous persons for whom sleep is a sort of magico-religious state in which the mind, being partially relieved of the body, has a sharpness of vision which it does not enjoy during waking moments, do not go to the point of considering all their dreams as so many mystic intuitions: on the contrary, along with everybody else, they see in the majority of their dreams only profane conditions, vain plays of images, or simple hallucinations. It might be supposed that the primitive should make analogous distinctions. Codrington says distinctly that the Melanesians do not attribute all their dreams indiscriminately to the wanderings of their souls, but merely those which strike their imagination forcibly:[109] undoubtedly by that should be understood those in which the sleeper imagines himself in relations with religious beings, good or evil geniuses, souls of the dead, etc. Similarly, the Dieri in Australia sharply distinguish ordinary dreams from those nocturnal visions in which some deceased friend or relative shows himself to them. In the first, they see a simple fantasy of their imagination; they attribute the second to the action of an evil spirit.[110] All the facts which Howitt mentions as examples to show how the Australian attributes to the soul the power of leaving the body, have an equally mystic character. The sleeper believes himself transported into the land of the dead or else he converses with a dead companion.[111] These dreams are frequent among the primitives.[112] It is probably upon these facts that the theory is based. To account for them, it is admitted that the souls of the dead come back to the living during their sleep. This theory was the more readily accepted because no fact of experience could invalidate it. But these dreams were possible only where the ideas of spirits, souls and a land of the dead were already existent, that is to say, where religious evolution was relatively advanced. Thus, far from having been able to furnish to religion the fundamental notion upon which it rests, they suppose a previous religious system, upon which they depended.[113]