444 Mental Factors in Evolution 
man from those of the lower animals has been brought about—a 
differentiation the existence of which he again and again acknow- 
ledges. His purpose was rather to show that, notwithstanding this 
differentiation, there is basal community in kind. This must be 
remembered in considering his treatment of the biological founda- 
tions on which man’s systems of ethics are built. He definitely 
stated that he approached the subject “exclusively from the side of 
natural history.” His general conclusion is that the moral sense is 
fundamentally identical with the social instincts, which have been 
developed for the good of the community ; and he suggests that the 
concept which thus enables us to interpret the biological ground-plan 
of morals also enables us to frame a rational ideal of the moral end. 
“As the social instincts,” he says’, “both of man and the lower animals 
have no doubt been developed by nearly the same steps, it would be 
advisable, if found practicable, to use the same definition in both cases, 
and to take as the standard of morality, the general good or- welfare 
of the community, rather than the general happiness.” But the kind 
of community for the good of which the social instincts of animals 
and primitive men were biologically developed may be different from 
that which is the product of civilisation, as Darwin no doubt realised. 
Darwin’s contention was that conscience is a social instinct and has 
been evolved because it is useful to the tribe in the struggle for 
existence against other tribes. On the other hand, J. S. Mill urged 
that the moral feelings are not innate but acquired, and Bain held 
the same view, believing that the moral sense is acquired by each 
individual during his life-time. Darwin, who notes* their opinion 
with his usual candour, adds that “on the general theory of evolution 
this is at least extremely improbable.” It is impossible to enter into 
the question here: much turns on the exact connotation of the terms 
“conscience” and “moral sense,” and on the meaning we attach to 
the statement that the moral sense is fundamentally identical with 
the social instincts. 
Presumably the majority of those who approach the subjects 
discussed in the third, fourth and fifth chapters of The Descent of 
Man in the full conviction that mental phenomena, not less than 
organic phenomena, have a natural genesis, would, without hesitation, 
admit that the intellectual and moral systems of civilised man are 
ideal constructions, the products of conceptual thought, and that as 
such they are, in their developed form, acquired. The moral senti- 
ments are the emotional analogues of highly developed concepts. 
This does not however imply that they are outside the range of 
natural history treatment. Even though it may be desirable to 
1 Descent of Man, Vol. 1. p. 149. 2 Ibid. p. 185. 
3 Ibid. p. 150 (footnote). 
