Animal Psychology, the Old and the New 15 



knowledge extends only to bodily things, but intellect 

 takes cognizance of things incorporeal, as wisdom, 

 truth and the relations between objects." The won- 

 derful adaptiveness and perfection of instinct are 

 not to be ascribed, in any measure, to the animal's 

 own initiative, but redound to the credit of the Cre- 

 ator. 



The ideas of Aquinas on animal psychology, like 

 his ideas on so many other subjects, were greatly 

 influenced by the teachings of Aristotle, but he em- 

 phasized much more than his master did the differ- 

 ences between -brute and human intelligence. Aris- 

 totle greatly perplexed his followers and interpre- 

 ters by his vague and somewhat vacillating treat- 

 ment of the relations of the rational soul to the sen- 

 sitive soul and to the body. But the learned St. 

 Thomas promptly settles these problems with a de- 

 cisiveness that leaves no room for doubt concerning 

 his own standpoint. The writings of Aquinas served 

 to define the position of the church in regard to the 

 status of the animal mind. The opinions of this 

 prelate were widely followed and have continued 

 to influence opinion even down to the present time. 



In the writings of Descartes we find animal be- 

 havior interpreted, for the first time, in terms of 

 the functions of the nervous system. Descartes was 

 an original investigator of the structure and func- 

 tions of the nervous system and he arrived at many 

 of our fundamental conceptions of nerve physiology. 

 His celebrated doctrine that animals are automata, 



