CHAPTER X 



ANIMAL INSTINCTS AND TROPISMS* 



I. The idea that the organism as a whole cannot 

 be explained from a physicochemical viewpoint rests 

 most strongly on the existence of animal instincts 

 and will. Many of the instinctive .actions are "pur- 

 poseful," L e., assisting to preserve the individual and 

 the race. This again suggests "design" and a design- 

 ing "force," which we do not find in the realm of 

 physics. We must remember, however, that there was 

 a time when the same " purposef ulness " was believed 

 to exist in the cosmos where everything seemed to 

 turn literally and metaphorically around the earth, 

 the abode of man. In the latter case, the anthropo- 

 or geocentric view came to an end when it was shown 

 that the motions of the planets were regulated by 

 Newton's law and that there was no room left for the 



' Ideas similar to those expressed in this chapter may be found in the 

 writer's former book Comparative Physiology of the Brain and Compara- 

 tive Psychology, New York, 1900, and in the books by George Bohn, 

 La Naissance de V Intelligence, Paris, 1909, and La nouvelle Psychologic 

 animale, Paris, 1911. 



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