14 Heredity and Social Progress 



slight, but it is through their agencies, acting 

 perhaps no more rapidly than at present, that 

 great mountain ranges were lowered. The 

 present changes throw light on the past, and 

 the study of former changes is necessary to a 

 knowledge of the present. It has been hap- 

 pily said, " Geology is the study of the past 

 in the light of the present, while geography 

 is a study of the present in the light of the 

 past." 



Do we not observe the same relations be- 

 tween biology and economics? The more 

 elementary forms of life and the lower ani- 

 mals may be said to be the past of human 

 evolution as geology is the past of physical 

 evolution. Each organism was a changing 

 being and then became a fixed type. Man, 

 however, is changing; all the forces that have 

 ever been at work on organisms are still at 

 work on him. He has upbuilding forces and 

 denuding forces ; they may be studied in ac- 

 tual operation just as the changes due to natu- 

 ral forces may still be studied in geography. 



The laws of human evolution are the laws 

 of natural evolution, and the order of its 



