136 ADAPTATION AND PROGRESS 
elements in the environment (especially in new races), progress of 
the sciences and industry, by education, beliefs, and in many 
other ways. “Ideas,” he says, “ can have no real action on the 
soul of peoples until, as the consequence of a very slow elaboration, 
they have descended from the mobile regions of thought to that 
stable and unconscious region of the sentiments in which the 
motives of our actions are elaborated. They then become ele- 
ments of character and may influence conduct.” 1 
As to the mechanism of propagation of new ideas, it is held to be 
by innovation on the part of the élite and imitation on the part of 
the masses,? under some conditions taking a form analogous to 
contagion. Religious beliefs, he holds, have always constituted 
the most important element of the life of peoples.* 
Le Bon makes verbal connection with our general subject in 
these words: — 
The history of civilization is . . . composed of slow adaptations, of 
slight successive transformations. . . . The brain cells do not assimilate in 
a day what it has taken centuries to create, and what is adapted to the senti- 
ments and needs of organisms that differ from one another. Only slow 
hereditary accumulations allow of such assimilation; § 
but his whole discussion is an elaboration of the concept of psychi- 
cal unity applied to the group, this unity being the progressive 
result of the law of adaptation, the individual member forced to 
adapt himself to the group and the group-soul progressively 
changing in response to new needs until it has attained its full 
growth when there ensues a period of decline. 
Thus with the progress of social evolution and in accordance 
with the law of adaptation we find different social groupings so 
united by a common physiological and psychological heritage, so 
bound together by common interests and ideals, and responding 
so alike to a common stimulus that we may well speak of such 
groups as having a “soul.’’® Though in describing the soul of any 
particular group whether city or state we may use the normal 
frequency curve representing all the people, it is the variation 
1 Psychology of Peoples, p. 168. 4 Psychology of Peoples, p. 190. 
2 Tbid., p. 174. 5 Ibid., p. 96. 
3 Developed in his Crowds. § Ibid., pp. 6, 59, 146, 17%. 
