loS E. L. THORNDIKE. 



tent of territory covered and the need of brevity have prevented 

 completeness in explanation or illustration. If the reader cares 

 here, at the end, to have the broadest possible statement of our 

 conclusions and will take the pains to supply the right meaning, 

 we might say that our work has described a method, crude but 

 promising, and has made the beginning of an exact estimate of 

 just what associations, simple and compound, an animal can 

 form, how quickly he forms them, and how long he retains 

 them. It has described the method of formation, and, on the 

 condition that our subjects were representative, has rejected rea- 

 son, comparison or inference, perception of similarity, and 

 imitation. It has denied the existence in animal consciousness 

 of any important stock of free ideas or impulses, and so has de- 

 nied that animal association is homologous with the association 

 of human psychology. It has homologized it with a certain lim- 

 ited form of human association. It has proposed, as necessary 

 steps in the evolution of human faculty, a vast increase in the 

 number of associations, signs of which appear in the primates, 

 and a freeing of the elements thereof into independent existence. 

 It has given us an increased insight into various mental pro- 

 cesses. It has convinced the writer, if not the reader, that the 

 old speculations about what an animal could do, what it thought, 

 and how what it thought grew into what human beings think, 

 were a long way from the truth, and not on the road to tt. 



Finally, I wish to say that, although the changes proposed in 

 the conception of mental development have been suggested 

 somewhat fragmentarily and in various connections, that has 

 not been done because I think them unimportant. On the con- 

 trary, I think them of the utmost importance. I believe that 

 our best service has been to show that animal intellection is 

 made up of a lot of specific connections, whose elements are re- 

 stricted to them, and which subserve practical ends directly, and 

 to homologize it with the intellection involved in such human 

 associations as regulate the conduct of a man playing tennis. 

 The fundamental phenomenon which I find presented in animal 

 consciousness is one which can harden into inherited connections 

 and reflexes, on the one hand, and thus connect naturally with a 

 host of the phenomena of animal life ; on the other hand, it 



