The Logic of Evolution 



ress demand more than mere knowledge of sur- 

 roundings or environment. Conformity to envi- 

 ronment is the essential thing. The knowledge 

 must result in action, the intellect must stir the 

 will before any real progress can result. Hence 

 the study of perceptions, of discovery, is prac- 

 tically of less importance than that of the motives 

 which have stimulated and determined the line 

 of action; for the line of action and habits in- 

 fluences that of selection and survival, and hence 

 of evolution. Perhaps we ought not to speak 

 of motives among the lowest animals. But we 

 may venture to use this expression in spite of the 

 fact that it implies will and choice. There is 

 no better familiar word to take its place. 



The only motive which the lowest animal can 

 feel and which can spur him to action is hunger, 

 and perhaps we ought to add pain. Worms 

 avoid danger. They act as if they had a dim 

 feeling of fear.. Fear may be a low and primi- 

 tive motive, but it is of great importance. Even 

 the man who cannot fear is either dull or ex- 

 ceedingly reckless. He certainly is not wise. 

 Anger and jealousy soon follow. 



The social instinct beginning with a mere gre- 

 garious feeling goes on into love of mates. The 



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