DARWIN 



inability to follow abstract thinking. When we turn 

 to the scientific aspects of the theory we should find a 

 different condition of affairs. He was undoubtedly 

 a marvellously keen observer and his powers of scien- 

 tific generalization were of the best; yet, even from 

 the scientific aspect, Darwin's work to establish nat- 

 ural selection is rapidly crumbling on its biological 

 side. This result is again to be traced indirectly to the 

 same deficiency of his mind; he could generalize cor- 

 rectly so long as he confined himself to a narrow field 

 which lay immediately under his own observation, 

 but he could not sustain himself, because of his lack 

 of imagination, when it was necessary to include so 

 vast a field as the evolution of all organisms. 



Darwin based his theory of natural selection on the 

 analogy of the results which man has obtained by se- 

 lective breeding of domesticated animals; he did an 

 enormous amount of work in this field and collected 

 much curious and valuable information about selec- 

 tive breeding. But he never seems to have once real- 

 ized that the analogy is purely specious because the 

 variations of domesticated animals and plants have, 

 in man, a directing force which can arrange and alter 

 the animals' habits, instincts, and environment, so as 

 to foster certain variations and eliminate others. The 

 one essential thing for a rational theory of evolution 

 is to discover what directs the, to us, chance varia- 

 tions of undomesticated organisms so that minute 

 changes will accumulate in a continuous increase un- 



