THE concept of a spirit’s entering into an inanimate object, an animal, or a human being, is a very ancient and honorable belief, having prevailed since the beginning of the evolution of religion. This doctrine of spirit possession is nothing more nor less than fetishism. The savage does not necessarily worship the fetish; he very logically worships and reverences the spirit resident therein.
At first, the spirit of a fetish was believed to be the ghost of a dead man; later on, the higher spirits were supposed to reside in fetishes. And so the fetish cult eventually incorporated all of the primitive ideas of ghosts, souls, spirits, and demon possession.