228 SCIENCE AND THE HUMAN MIND 



economist desired to emulate, without understanding, 

 the discoveries of Newton. His view, analogous to 

 the immutability of species of the older zoology, was 

 undermined by the historical school, which, in many 

 directions, has shown that economic laws are only 

 valid in suitable circumstances, and that their appli- 

 cation changes with the ever- varying environment. 



But, as in biology, the changes in political institu- 

 tions and in economic conditions are alike slow. We 

 cannot take short cuts to the next stage by means of 

 a surgical operation ; nor indeed do we know where 

 the next stage will lead us. Survivals of past times 

 are found side by side with rudimentary forms ready 

 for new growth. As morphology discloses in the 

 animal body vestiges of organs useful in past phases 

 of organic evolution, so the study of social institutions 

 shows traces of the older stages through which they 

 have passed. From these traces, rightly interpreted, 

 their history and origin may ofttimes be inferred. And 

 from a knowledge of history and origin light is cast 

 on present meaning and true significance. Such books 

 as Tylor's Primitive Culture and Frazer's Golden Bough 

 show how the concepts of evolution illumine the study 

 of sociology. 



If man has been brought into being by the same pro- 

 cesses of evolution as the animal races, he must be sub- 

 ject still to the same variation and selection. Darwin's 

 cousin, Francis Galton, working on this idea, traced the 

 inheritance of physical and mental qualities in mankind, 

 and showed that, to secure the continued progress of 

 the race in the direction that civilized men have agreed 

 to consider upward, even to prevent its deterioration, 

 it was necessary that selection should continue. 



