PKOGRESS AND DIFFERENTIATION. 28 1 



for life acts so as to transform human society, just as 

 it modifies animals and plants, and in both cases con- 

 stantly produces new forms. The comparison of the phe- 

 nomena of human and animal transformation is especially 

 interesting in connection with the laws of divergence and 

 progress, the two fundamental laws which, at the end of the 

 last chapter, we proved to be direct and necessary conse- 

 quences of natural selection in the struggle for life. 



A comparative survey of the history of nations, or what 

 is called " universal history," will readily yield to us, as the 

 first and most general result, evidence of a continually in- 

 creasing variety of human activities, both in the life of in- 

 dividuals and in that of families and states. This differenti- 

 ation or separation, this constantly increasing divergence of 

 human character and the form of human life, is caused by 

 the ever advancing and more complete division of labour 

 among individuals. While the most ancient and lowest 

 stages of human civilization show us throughout the same 

 rude and simple conditions, we see in every succeeding 

 period of history, among different nations, a greater variety 

 of customs, practices, and institutions. The increasing divi- 

 sion of labour necessitates an increasing variety of forms 

 corresponding to it. This is expressed even in the for- 

 mation of the human face. Among the lowest tribes of 

 nations, most of the individuals resemble one another so 

 much that European travellers often cannot distinguish 

 them at all. With increasing civilization the physiognomy 

 of individuals becomes differentiated, and finally, among the 

 most highly civilized nations, the English and Germans, 

 the divergence in the characters of the face is so great that 

 we very rarely mistake one face for another. 



