xvi Introduction 



From the point of view of promoting knowledge, the 

 subject matter of a study should be presented as objectively 

 as possible. There should be a statement of the facts mar- 

 shalled to bring out their relationship, and there should be 

 a statement of the generalizations derived from these facts, 

 of the theoretical interpretations of the facts, and of their 

 practical significance. It is almost impossible today to dis- 

 cuss evolution in this manner. Objective and inductive 

 study is so new a method in the intellectual life of the race 

 that most people still get their views of the world as finished 

 pictures transmitted by authority. The diffusion of special- 

 ized knowledge among the general public is so recent a de- 

 velopment that most men and women approach the subject 

 of evolution from a background of doctrine with which 

 evolution is supposed to be in conflict. With every desire 

 to avoid argument, we find ourselves contrasting the plausi- 

 bility of an evolutionary interpretation with that of special 

 creation. As attention is fixed more and more upon the facts, 

 however, the evolutionary interpretation becomes progres- 

 sively more satisfying to the thoughtful person, notwith- 

 standing the increasing difficulty of " explaining " evolution 

 by any simple formula. 



This book attempts to separate the presentation of evolu- 

 tion as a historical process from the various theories designed 

 to account for the origin of species in a rational manner. The 

 purpose is not to convert skeptics and doubters but to inform 

 all and sundry ( i ) of the meaning of the doctrine from the 

 point of view of the scientist; (2) of the facts upon which it 

 rests; (3) of the more important attempts to explain the 

 processes discussed; and (4) of the practical implications of 

 the point of view involved. 



