All sorts of theories have been advanced, in the search for a plausible explanation, but again, in all the ages of civilization, no conclusive proof has been found that any one of them is the right one.
In ancient times the theory seemed to be that the purpose of life was to develop the body to its highest state of prowess and beauty and to make liberal sacrifices to the gods, in order to gain and retain their favor. The idea seems to have been current for many centuries that when the spirit mounted to another world, it somehow carried the shape and characteristics of the earthly body along with it. Reason enough to make the body strong and beautiful, if the spirit were to continue tied up to it eternally.
Even in Shakespeare's time and all through the Middle Ages, whenever departed spirits were supposed to come back to earth to communicate with mortals, they always appeared in the same bodily form they had had on earth.
On this assumption, if one individual happened to die when his body was young and strong and handsome, his spirit would have an advantage over another individual, who lasted on earth until his body was old, decrepit and ugly.
It may be that the unfairness of this thought had something to do with the eventual discarding of the belief. It may also be that in the course of time and accumulated experience, the more advanced intellects arrived at the conclusion that sacrifices made to the gods had little perceptible effect on the course of events. In any case European civilization appears to have arrived at a stage where it was ripe and ready for another sort of conception.
This other conception was the unimportance and unworthiness of the body and all material things. The spirit was the only thing that signified and that was to be dedicated to the service of the Lord, as announced in divine commandments. Sacrifices on the altar or gifts to the priests would avail nothing, if the spirit were undutiful. The Lord was to be worshipped and addressed in prayer—and He was at all times prepared to mete out rewards and punishments in strict accordance to the deserts of the spirit. Good and worshipful spirits would be blessed with everlasting life in paradise, while those who disobeyed the commandments, or neglected to be baptized and worship in the ordained way would be consigned to eternal torture and damnation.
This theory was accepted by many millions of people and for a long time held an awe-inspiring sway over their imaginations.
At the same time, in different parts of the world, India, China, Mexico, Egypt and various countries, a number of other theories concerning the spirit and the body were advanced as the basis of religious beliefs; and these were accepted by countless other millions of people with the same awe-inspiring credulity.
One feature of these various religions which appears to apply to them all, is worth noting. Each professed the belief that their God or gods ruled in supreme control of the entire universe, eternally, and that all other so-called gods and so-called religions of other peoples which interfered with this idea must necessarily be false and spurious.
In this respect, our own Christian view is like the others. In pursuance of it, immense sums of money, untiring effort and many lives have been spent by devout believers to convince remote peoples of the error of their doctrines and the truth of ours.