appearance of the thinking, self-regulating life distinctly human."
Thus, according to some of the best thinkers, the explanation of the
moral and spiritual nature of man as a development of the animal
nature, is quite insufficient and unsatisfactory. The theory of
natural selection in the struggle for existence cannot explain the
cause of the higher nature of man. We cannot say that a theory is
complete because it explains many facts. On the contrary, if it fails
to explain a single fact, then it is proved to be incomplete. As such,
the theory that cannot explain satisfactorily the cause of the moral
and spiritual nature of man cannot be accepted as a complete
theory. That explanation will be considered as complete which will
explain most satisfactorily all the various manifestations of the
animal, moral and spiritual nature. Moreover, supposing the "tendency
to vary" has evolved into the moral and spiritual nature of man,
science does not explain the cause of that tendency to vary, nor how
animal nature can be transformed into moral and spiritual nature. Is
that "tendency to vary" indefinite, or is it limited by any definite
law? Science does not say anything about it.

The explanation of the theologians, that the spiritual nature has been
superadded to the animal nature by some extra-cosmic spiritual agency
is not scientific, nor does it appeal to our reason. Now let us see
what Vedanta has to say on this point. Vedanta accepts evolution and
admits the laws of variation and natural selection, but goes a step
beyond modern science by explaining the cause of that "tendency to
vary." It says, "there is nothing in the end which was not also in the
beginning." It is a law which governs the process of evolution as well
as the law of causation. If we admit this grand truth of nature, then
it will not be difficult to explain by the theory of Evolution the
gradual manifestation of the higher nature of man. The tendency of