The theory of Reincarnation when properly understood will appear as a supplement to the theory of Evolution. Without this most important supplement the Evolution theory will never be complete and perfect. Evolution explains the process of life, while Reincarnation explains the purpose of life. Therefore, both must go hand in hand to make the explanation satisfactory in every respect.
James Freeman Clarke says:
“That man has come up to his present state of development by passing through lower forms, is the popular doctrine of science to-day. What is called Evolution teaches that we have reached our present state by a very long and gradual ascent from the lowest animal organizations. It is true that the Darwinian theory takes no notice of the evolution of the soul, but only of the body. But it appears to me that a combination of the two views would remove many difficulties which still attach to the theory of natural selection and the survival of the fittest. If we are to believe in Evolution let us have the assistance of the soul itself in this development of new species. Thus science and philosophy will co-operate, nor will poetry hesitate to lend her aid.”
(P. 190, “Ten Great Religions,” II.) Evolution of the body depends upon the evolution of the germ of life or the individual soul. When these two are combined the explanation becomes perfect.
The theory of Reincarnation is a logical necessity for the completion of the theory of Evolution. If we admit a continuous evolution of a unit of the germ of life through many gross manifestations then we unconsciously accept the teachings of the doctrine of Reincarnation. In passing through different forms and manifestations the unit of life does not lose its identity or individuality. As an atom does not lose its identity or individuality (if you allow me to suppose an atom has a kind of individuality) although it passes from the mineral, through the vegetable, into the animal, so the germ of life always preserves its identity or individuality although it passes through the different stages of evolution.
Therefore it is said in the “Bhagavad GÃ®tÃ¢,” as in our ordinary life the individual soul passes from a baby body to a young one and from a young to an old, and carries with it all the impressions, ideas and experience that it has gathered in its former stage of existence and reproduces them in proper time, so when a man dies the individual soul passes from an old body into a new one, and takes with it the subtle body wherein are stored up all that it experienced and gathered during its past incarnations.
Knowing this, wise men are never afraid of death. They know that death is nothing but a mere change from one body into another. Therefore, if any one does not succeed in conquering the lower nature by the higher, he will try again in his next incarnation, after starting from the point which he reached in his past life. He will not begin again from the very beginning, but from the last stage at which he arrived. Thus we see that Reincarnation is the logical sequence of evolution. It completes and makes perfect that theory and explains the cause of the moral and spiritual nature of man.