Man can contemplate his own mortality and finds the thought intolerable. Any animal will struggle to protect itself from a threat of death. Faced with a predator, it flees, hides, fights or employs some other defensive mechanism, such as death-feigning or the emission of stinking fluids. There are many self-protection mechanisms, but they all occur as a response to an immediate danger. When man contemplates his future death, it is as if, by thinking of it, he renders it immediate. His defence is to deny it. He cannot deny that his body will die and rot — the evidence is too strong for that; so he solves the problem by the invention of an immortal soul — a soul which is more “him” than even his physical body is “him.” If this soul can survive in an afterlife, then he has successfully defended himself against the threatened attack on his life. This gives the agents of the gods a powerful area of support. All they need to do is to remind their followers constantly of their mortality and to convince them that the afterlife itself is under the personal management of the particular gods they are promoting. The self-protective urges of their worshippers will do the rest.

— Desmond Morris