4 INTRODUCTION 
“‘ Each of us,” says Ross, “ considers a change progressive 
when it advances society toward his ideal. But one man’s ideal 
is freedom, while another’s is order; one man borrows from biol- 
ogy the criterion of differentiation, while another imports from 
psychology the idea of harmony; one man’s touchstone is the 
happiness of the many, while another’s is the perfecting of the 
superior few. It is, therefore, hopeless as yet to look for a test of 
progress that shall be objective and valid for all. Since change is 
a matter of observation, whereas progress is a matter of judgment 
involving the application of a subjective standard, those who 
desire to see sociology a true science are justified in insisting that 
social dynamics deal with the factors and manner, not of social 
progress merely, but of social change.” 1 This is very true for 
sociology as a science which deals with facts and laws, but sociol- 
ogy is also a philosophy which evaluates. Social science observes 
and systematizes social phenomena and their relations; but social 
philosophy seeks to understand these phenomena not merely in 
their relations of co-existence and sequence but as a system, —a 
causal order. 
It is nearly a hundred years since Auguste Comte gave the 
world his Positive Philosophy as a theory of social progress, first as 
lectures, later in published form. Since then many have followed 
in his footsteps and many more, without pretending to think 
social phenomena as a whole, have contributed to social science 
by the discovery and formulation of social laws. 
In the history of social science and social philosophy, if I 
observe correctly, one word, or the principle of which it is the 
symbol, stands out with ever increasing prominence, — that of 
adaptation. It is the main purpose of this book to trace the 
development of this doctrine as a theory of social progress. 
The Value of Social Philosophy.—Our discussion will lead us to 
consider such questions concerning the social group, large and 
small, as have ever perplexed thoughtful souls concerning their 
own existence, whence, how, whither, and why?® But as con- 
sideration of such ultimate questions is tabooed by so many in 
1 Foundations of Sociology, p. 186. 
* Cf. Ward, Applied Sociology, p. 3. 
