34 Studies in Animal Behavior 



development of their animal friends. 



There is little ground for believing that animals 

 have abstract or general ideas, or the power of de- 

 liberate reasoning, but there is considerable experi- 

 mental evidence that they have ideas of a simple 

 sort and a certain power of inference. Careful in- 

 vestigators at present show a wholesome caution 

 about ascribing to the mind of the animal more 

 than the facts really justify. Lloyd Morgan has 

 laid down the principle, since known as the principle 

 of Morgan, that no act should be ascribed to a 

 higher mental faculty if it can be satisfactorily ac- 

 counted for in terms of a lower one. The burden 

 of proof is thus placed upon those who contend for 

 the superior endowments of the animal mind. What 

 we want are not stories of performances which 

 might have involved unusual intelligence, but records 

 of achievements which cannot be accomplished ex- 

 cept by means of unusual intelligence. In the latter 

 case only are we justified in ascribing to the animal 

 the mental attribute in question. In following the 

 principle of Morgan we may often fail to give to 

 the animal full credit for the faculties it may really 

 possess, but our conclusions will be sound so far as 

 they go. 



