ANIMAL AND RATIONAL INTELLIGENCE 241 



of the law of natural selection. It will present!} 7 

 appear that our estimates of memory and imagination 

 must be restricted in like manner. In passing these, 

 we do not overlook them as characteristics of animal 

 life. We only fix attention on the action of intelligence 

 in order to ask the single question : Can Animal Intel 

 ligence account for evolution of rational power ? 



We advance along the single available line, when 

 we consider the relation of simple ideas to those more 

 complex, inquiring whether there can be any causal 

 relation between these two. We ask whether inter 

 pretation of signs can unfold into the higher exercises 

 enumerated. We seek to have it decided whether 

 those effects of training appearing in the intelligence 

 of the dog, can be regarded as disclosing operations 

 contributing towards evolution of human intelligence. 

 Dr. Romanes, drawing upon Locke s discussion of the 

 question, how far brutes partake in the comparing 

 and compounding of simple ideas, 1 has directed 

 inquiry along the proper line. 2 By following this, we 

 may reach some clear understanding of the relations 

 of animal intelligence to human. How do the simple 

 ideas of the dog, compare with the complex ideas 

 of man ? The mental exercise of the animal must be 

 placed alongside the reflective exercise of man. In 

 this way, we may find it possible to say whether the 

 simpler has potency for evolving the higher. 



Keeping to the terms used by Locke, Romanes 

 speaks of the comparing, compounding, and en 

 larging of ideas ; admitting that the procedure Locke 

 has in view is the conscious or intentional comparing, 



1 Locke s Essay, Ch. on Discerning, Bk. n. chap. xi. 5. 

 - Romanes s Mental Evolution in Man, p. 28. 



