127 
Inconsistencies of Utilitarianism . 
forms, in whatever way it is secured, is the one necessary 
and always effective causeof divergence, so, in nature, wherever 
there arises the isolated breeding of other than average 
forms, there divergence will be produced ; or that, as exposure 
to different environments is only one of the causes that lead 
isolated bands of men to desire and select different types of 
variation in the same species of animal, so exposure of wild 
species to different environments is only one of several classes 
of causes that may subject isolated portions of one of these 
species to different forms of selection, producing divergence ; 
or, again, that as differences in the uses to which men put an 
animal are not necessarily useful differences, so the differences 
in the uses which isolated portions of a species make of the 
environment, though they produce diversity of natural selec- 
tion, leading to permanent divergence, are not necessarily 
useful differences. These, with other allied doctrines, which 
were presented in my paper on u Divergent Evolution through 
Cumulative Segregation,” have received adverse criticism 
from Mr. Wallace in the work mentioned above. He says : — 
a In Mr. Gulick’s last paper (Journ. of Linn. Soc., Zoology, 
vol. xx. pp. 189-274) he discusses the various forms of 
isolation above referred to under no less than thirty-eight 
different divisions, with an elaborate terminology, and he 
argues that these will frequently bring about divergent evolu- 
tion without any change in the environment or any action 
of natural selection. The discussion of the problem here 
given will, I believe, sufficiently expose the fallacy of his 
contention ; but his illustrations of the varied and often recon- 
dite modes by which practical isolation may be brought 
about may help to remove one of the popular difficulties in 
the way of the action of natural selection in the origination 
of species ” (note on p. 150). 
In this passage Mr. Wallace seems to take issue with each 
and all of my propositions ; but after a careful study of his 
whole discussion one cannot but be in doubt whether he fully 
dissents from any of them. This uncertainty arises either 
from his failing to recognize distinctions which I have made, 
or from ambiguities and inconsistencies in his own statements. 
Extending the meaning of Natural Selection does 
not save the Theory . 
He represents me as contending that divergent groups are 
frequently found in which the action of natural selection is 
wanting. He here fails to distinguish between the absence of 
diversity in the action of natural selection and the absence of 
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