456 PROGRESS OF SCIENCE IN THE CENTURY. 



perhaps have been expected, an auspicious beginning 

 has been made. 



Historical Outline. Though Descartes set a 

 splendid example, there were few in pre-Darwinian 

 days who even attempted a scientific study of the 

 animal mind. Even those who were careful ob- 

 servers usually remained content with theological or 

 metaphysical interpretations. H. S. Reimarus, who 

 published a large work on Instincts in 1760, and the 

 philosopher Schelling may be named as representa- 

 tive. 



The development of physiology (e.g., the theory 

 of reflexes) and of human psychology, and the in- 

 fluence of the evolution-idea, led to a more scientific 

 outlook. Alfred Russel Wallace and others showed 

 that many cases of alleged instinctive activity were 

 really cases of rapid learning and that " instincts " 

 were neither so perfect, unerring, or stereotyped as 

 had been supposed. An attempt was made to arrange 

 vital activities in a psychological series as if on 

 an inclined plane automatic physiological rhythms, 

 simple reflexes, complex reflexes, instinctive activi- 

 ties, habitual intelligent actions, intelligent behav- 

 iour, and rational conduct. Theories as to the 

 origin of instincts began to abound, the Lamarckian 

 school regarding them as the outcrop of inherited 

 habits (either intelligent activities or complex re- 

 flexes to start with), the strict Darwinian school re- 

 garding them as the result of the action of Natural 

 Selection on congenital cerebral variations. 



Although the term " instinctive activity " is still 

 used to include several different modes of action, we 

 have placed it on the inclined plane between reflex 

 action and habitual intelligent action. Instinctive 

 activities differ from habitual-intelligent activities in 



