INTRODUCTION 7 
his day great advance has been made and the leaders of thought 
and life in the western world are coming to agreement as never 
before on fundamental principles of life and progress. 
During the last quarter of the nineteenth century evolution 
was the open sesame to the interpretation of all phases of life, but 
this term has proven too vague. More and more that general 
concept is being analyzed, narrowed, defined. Its place, as we 
shall see, is being usurped by the more definite concept of adap- 
tation, which has already obtained a foremost place in educational 
philosophy, even in that narrower and more conservative sphere 
of education which is concerned primarily with the religious phase 
of life, and is invading, too, the domain of political science. A 
second purpose of this thesis, then, will be to indicate the utility 
of this concept of adaptation in interpreting various phases of 
social endeavor. 
Method.— Our subject naturally calls for an analysis of systems 
of social philosophy with the one special aim of showing the con- 
tribution of each to this doctrine of adaptation. It will be in our 
province, also, to investigate the writings of others outside the 
sphere of sociology proper who have contributed to the develop- 
ment of this doctrine. We shall not attempt, however, to trace 
this development back in its several root forms to early ages. 
Such a task would be too great and of too little value. Indeed 
this field has been cultivated already to a considerable extent. 
Professor Osborn has traced the development of the doctrine of 
adaptation as a theory of biological evolution back to the early 
Greek physicists, especially to Empedocles,! and Professor 
Flint’s Philosophy of History contains abundant material for the 
study of the use of this concept among early social philosophers. 
Modern sociology is generally conceded to take its rise from 
Auguste Comte, so our investigation may well begin with him, 
although reference will be made to some who lived in an earlier 
age. 
Several methods of procedure are open to us. The subject 
suggests a historical method, but inasmuch as the period covered 
is less than a century such a method presents many difficulties. 
1 From the Greeks to Darwin. 
