Darwin, has established certain positions which have been regarded as
of special significance for ethics.

In the first place, it is an assertion of the unity of life. And we
must not limit the generality of this proposition. It is not merely
a denial of the fixity of species, an assertion that there are no
natural kinds so inseparable from one another that each must be the
result of a distinct creative act. It is also an assertion that human
life must be treated as a part in the larger whole of organic being,
that the mind of man is continuous with animal perception, that moral
activity is continuous with non-moral impulse. And the assertion of
the unity of life is at the same time an assertion of the progress of
life. What we call the higher forms are in all cases developments from
simpler and lower forms.

Further, the method of this progress has been described. Herein indeed
lay Darwin's most important achievement. He detected and demonstrated
the operation of a factor hitherto unsuspected. This new factor to
which he drew attention as the chief agent in organic development was
called by him 'natural selection,' The name has a positive sound and
suggests a process of active choice. But Darwin was fully aware that
the process to which he gave this name was a negative and not a
positive operation; and as such it was clearly recognised by him. The
name was, no doubt, chosen simply to bring out the fact that the
same kind of results as those which man produces by conscious and
artificial selection may be arrived at without conscious purpose by
the operation of merely natural forces. Instead of the 'fit' being
directly chosen or encouraged, what happens is simply that the 'unfit'
die out or are exterminated, so that room to live and means of life
are left for the survivors.