468 KINSHIP AND ADAPTATION 
becomes simplified in the course of its evolution and, so passes 
to a lower level of structure, it is said to degenerate. Much 
more extreme instances of degeneration will be dealt with in 
the following chapter. 
It thus appears that degeneration, persistence, and extinc- 
tion of types accompanies the general progress which charac- 
terizes organic evolution. In the evolution of human society 
likewise we find degeneration, persistence, and extinction of 
races along with a general progress of mankind from savagery 
to civilization. Here as in the evolution of lower organisms we 
may observe adaptation to changed conditions through sud- 
den or gradual modification. Migrations also play an import- 
ant part and have many consequences, among which conflicts 
are the most apparent although not necessarily the most sig- 
nificant. Periods of greater progress have been times of 
greater peace. Conflicts destroy or test; they do not create. 
Men or races unfit to live, if such there be, of course are better 
dead, and those menacing the progress of mankind are better 
subdued; but it is surely a partial view of human affairs that 
regards the world as one vast battlefield whose horrors have 
fostered the most precious characteristics of civilization. How- 
ever inevitable mortal conflicts have been, however fierce the 
struggle of competition, and however necessary it may have 
been to kill the worse that the better might live, we cannot 
say that anyone has been made better by the killing. Yet 
we may be sure that human advance toward the most perfect 
and abundant life has been delayed, and that whatever real 
progress Man has made has been in spite of his competitive 
struggles. The economies of co-operation and the advantages 
of mutual service achieve what competition never can. Mere 
struggle for supremacy when fiercest destroys most of what 
is best. Man’s mastery over nature and over his lower self 
has come through learning and choosing the better way. 
The evolution of mankind and that of lower organisms 
are alike in so many ways, it is thought that each may throw 
light upon the other. In human progress we recognize as the 
controlling factors of change: Opportunity,—offered by the 
environment; Experience,—representing its effect; Choice,— 
as the response to it, guided by Ideals. Of these the pivotal 
