Animal Psychology, the Old and the New 29 



adaptations quite independently of natural selection. 

 This is done by endowing the organism with a teleo- 

 logical principle which makes all the adjustments re- 

 quired to meet its needs ; these adjustments are then 

 transmitted to the descendants and thus gradually 

 effect a progressive adaptive modification of the 

 species. 



Without raising the question as to whether the 

 vitalistic explanation of adaptation really explains 

 anything, it might be remarked that, since a teleo- 

 logically working principle is assumed as the basis 

 for the acquired adjustments of the individual, the 

 same principle might also be evoked to guide the 

 entire course of evolution without appealing to an 

 agency of such questionable potency as the Lamarck- 

 ian factor. Entia nan sunt multiplicanda praeter 

 necessitatem. If we invoke any vitalistic agencies 

 or ideological principles we might as well give them 

 plenty to do. 



The theory of organic evolution having been 

 firmly established, and the conviction having be- 

 come quite general among psychologists that the hu- 

 man mind has resulted by a continuous process of 

 development from the mind of animals, the contro- 

 versial Interest in various questions that stimulated 

 the earlier post-Darwinian students of the animal 

 mind has to a considerable extent subsided. The 

 effort to trace the evolution of particular instincts 

 and mental faculties continues to afford an absorbing 

 and fruitful occupation, but such work is pursued, 



