P952:3, 86:3.1 Death was the supreme shock to evolving man, the most perplexing combination of chance and mystery. Not the sanctity of life but the shock of death inspired fear and thus effectively fostered religion. Among savage peoples death was ordinarily due to violence, so that nonviolent death became increasingly mysterious. Death as a natural and expected end of life was not clear to the consciousness of primitive people, and it has required age upon age for man to realize its inevitability.
P952:4, 86:3.2 Early man accepted life as a fact, while he regarded death as a visitation of some sort. All races have their legends of men who did not die, vestigial traditions of the early attitude toward death. Already in the human mind there existed the nebulous concept of a hazy and unorganized spirit world, a domain whence came all that is inexplicable in human life, and death was added to this long list of unexplained phenomena.
P952:5, 86:3.3 All human disease and natural death was at first believed to be due to spirit influence. Even at the present time some civilized races regard disease as having been produced by "the enemy" and depend upon religious ceremonies to effect healing. Later and more complex systems of theology still ascribe death to the action of the spirit world, all of which has led to such doctrines as original sin and the fall of man.
P952:6, 86:3.4 It was the realization of impotency before the mighty forces of nature, together with the recognition of human weakness before the visitations of sickness and death, that impelled the savage to seek for help from the supermaterial world, which he vaguely visualized as the source of these mysterious vicissitudes of life.