It was impossible for a person to begin between death and life due to the maturity of his mind and the strength of his observation, or because he was preoccupied with what was more important to him, such as hunting, hunting, and self-defense. It must also be added to that that he was not social, or because most of the death incidents were unnatural. The end of humanity was killing, predation, or death in the forests.
When a person was less exposed to danger, he became more social and paid attention to long sleep. If the corpse became corrupted, the first thing he looked for was the reason for that, and his mind often came to the conclusion that what he saw was the result of an active act or magic. This is how a person came to the distinction between the soul and the body.