PREFACE 



The present volume consists of a series of eight 

 addresses delivered as the Hewitt Lectures of Columbia 

 University at Cooper Union in New York City during 

 the months of February and March, 1907. The purpose 

 of these lectures was to describe in concise outline the 

 Doctrine of Evolution, its basis in the facts of natural 

 history, and its wide and universal scope. They fall 

 naturally into two groups. Those of the first part deal 

 with matters of definition, with the essential character- 

 istics of Uving things, and, at greater length, with the 

 evidences of organic evolution. The lectures of the 

 second group take up the various aspects of human 

 evolution as a special instance of the general organic 

 process. In this latter part of the series, the subject 

 of physical evolution is first considered, and this is 

 followed by an analysis of human mental evolution; 

 the chapter on social evolution extends the funda- 

 mental principles to a field which is not usually con- 

 sidered by biologists, and its purpose is to demonstrate 

 the efficiency of the genetic method in this department 

 as in all others ; finally, the principles are extended 

 to what is called "the higher human life," the realm, 

 namely, of ethical, religious, and theological ideas and 

 ideals. 



Naturally, so broad a survey of knowledge could not 

 include any extensive array of specific details in any 



