268 Darwin, and after Darwin. 
the same community ; and thus we can understand 
the extraordinary degree in which not only co- 
operative instincts, but also largely intelligent social 
habits, have here been developed. Similarly, in the 
case of mankind, we can understand the still more ex- 
traordinary development of these things—culminating 
in the moral sense. I have heard a sermon, preached 
at one of the meetings of the British Association, 
entirely devoted to arguing that the moral sense could 
not have been evolved by natural selection, seeing 
that the altruism which this sense involves is the 
very opposite of selfishness, which alone ought to have 
been the product of survival of the fittest in a struggle 
for life. And, of course, this argument would have 
been perfectly sound had Darwin limited the struggle 
for existence to individuals, without extending it to 
communities. But if the preacher had ever read 
Darwin's works he would have found that, when thus 
extended, the principle of natural selection is bound 
to work in favour of the co-operative instincts in the 
case of so highly social an animal as man; and that 
of these instincts conscience is the highest imaginable 
exhibition. 
What I have called tribal fitness—in contra- 
distinction to individual fitness—begins with the 
family, developes in the community (herd, hive, clan, 
&c.), and usually ends with the limits of the species. 
On the one hand, however, it is but seldom that it 
extends so far as to embrace the entire species; while, 
on the other hand, it may in some cases, and as it were 
1 For cases, see Animal Intelligence, in the chapters on Ants and 
Bees; and, for discussion of principles, AZental Evolution in Animals, 
in the chapters on Instinct. 
