The theory of transmigration is one of the oldest theories accepted by the people of the Orient to solve the problems concerning life and death as well as to explain the continuity of existence after death. This theory presupposes the existence of the soul as an entity which can live even when the gross material body is dead or dissolved into its elements. Those who deny the existence of the soul, of the self-conscious thinker and actor, as an entity distinct from the gross material body, necessarily deny this theory of transmigration.
The materialistic thinkers of all ages have refused to accept this theory, because they do not admit the existence of a soul or a self-conscious thinker and actor as an entity, separate from the gross material body. Consequently they do not ask or discuss whether the soul will exist after death or not, whether it will continue to live or not. Such materialists are not the creatures of the twentieth century, but they have lived in all ages, in all countries. In India and in other civilized countries of ancient times you will find that materialistic thinkers prevailed and they gave the same arguments which we hear now from the agnostics and scientists of to-day. Their arguments are generally one-sided and unsatisfactory.
They try to deduce the soul or self-conscious entity from the combination of matter or material forces, but they have not succeeded in giving a scientific proof of it. No arguments in favor of the existence of a soul as an entity will convince them, because they deny the existence of anything that cannot be perceived by sense powers. If we could bring the soul down on the sense plane and make it visible to these materialistic thinkers, and if they could make experiments upon it, then perhaps they would be convinced to a certain extent, but not until then. But how can we bring the soul down on the sense plane when it is ethereal and finer than anything that we can perceive with our senses?
Those who try to explain the cause of our earthly life by the theory of heredity do not believe in the truth of transmigration. The modern scientists, agnostics and materialists generally accept the theory of heredity and endeavor to explain everything by it; but if we examine their arguments for the theory of heredity, we shall find that the theory of transmigration is much more satisfactory, much more rational than that of heredity.
Among the followers of the great religions of the world, the majority of Christians, Jews, Mohammedans and Parsees deny the truth of transmigration. Of course, there was a time when the Christians believed in this transmigration theory. Origen and other Church Fathers accepted it until the time of Justinian, who anathematized all those who believed in Reincarnation or the pre-existence of the soul. Among the Jews we find that in the Cabala this idea of transmigration plays the most important part. In fact the Cabalists accepted this theory to explain all the difficulties that could not be explained by any other theory. But those Jews, Christians, Mohammedans and Parsees who do not believe in the theory of transmigration accept the one-birth theory; that is, that God creates the souls at the time of birth out of nothing, and these souls, having come into existence out of nothing, continue to live forever; that this is our first and last birth that we receive; we did not exist before, we are suddenly created by God, and after death each one of us will continue to live either in heaven or hell to enjoy or to suffer throughout eternity. Among the modern Spiritualists we find that those who are born and brought up with this idea of one birth do not accept the theory of transmigration. Still there are millions and millions of people all over the world who do believe in transmigration and who have found comfort and consolation in their lives as well as a satisfactory solution of the problems of life and death.