limitation of the ethical significance of the principle of natural
selection. For, when we come to this crucial question of conduct,
it is not allowed to give any criterion of moral validity. More
comprehensive attempts on the same lines as Darwin's have been made
subsequently; and various writers have tried to show how the moral
criterion may be resolved into social efficiency, or how it may be
derived from a problematic future state of the human race on this
earth when the need for struggle has disappeared and all things
go smoothly. The former view may be found in Sir Leslie Stephen's
'Science of Ethics'; the latter is the peculiar property of Mr Herbert
Spencer. Somewhat unwillingly I must for the present leave these
special views without consideration,[2] because I wish to bring out
still more plainly the various attitudes of the evolutionists to
morality, and especially to draw attention to a view very different
from those just mentioned, though not altogether without support in
Darwin, which, as put forward some years ago by the late Professor
Huxley[3], produced no little flutter in scientific dovecots.

[Footnote 1: Descent of Man, pp. 205, 206.]

[Footnote 2: For a discussion of these views I may be allowed to
refer to my' Ethics of Naturalism,' chap. viii. (chap. ix. in the new
edition). The same volume contains a more exhaustive examination than
is possible in this lecture of the whole subject of evolutionist
ethics.]

[Footnote 3: The Romanes Lecture, 1893, "Evolution and Ethics." In
1894 this was republished, with prolegomena, in vol. ix. of 'Collected
Essays,' with the title, "Evolution and Ethics, and other Essays."]