Early Spiritual Belief
Experience due to the involuntary action of the brain in dreaming, when the ordinary laws of time and space are modified could hardly fail to impress the primitive imagination and suggest the duality of being—physical and spiritual.
In some savage communities at the present day there is a belief that the soul or spirit is absent during sleep and that it would be dangerous to wake the sleeper, as, should he close his mouth, the soul would be unable to return. This belief that the soul should be free to go and come is evidenced in the aperture that has been found in Kist-vaens and other forms of tombs.