When an individual belonging to one religious group joins another religious group after converting to that religion that, in religious terminology, is called proselytism. But this is a limited concept of conversion, which needs to be viewed in a more scientific light.
The religious view of conversion relates only to religious tradition. In this respect it is relatively limited in its spectrum. The scientific outlook, on the contrary, is much broader in scope, being based on the eternal principles of nature itself. Although it would be proper to say that, in the religious context conversion for human beings is a matter of choice, in the scientific sense, this is not so. It is an eternal principle of life, in exactly the same way as the laws of nature have the status of being immutable. We are compelled to accept the principle of conversion, just as we are compelled to accept the morning following the evening, or one season coming after another.