24 The Animal Mind 



minds, human or animal, until science consents to abandon 

 all hypotheses and inferences based on anything short of 

 perfect identity between instances. 



Is it possible to state briefly the special precautions that 

 must be observed in interpreting animal behavior as accom- 

 panied by consciousness, granted that such interpretation is 

 admissible ? Jordan, while holding that the existence of the 

 animal mind may fairly be inferred under certain circum- 

 stances, holds that we are not justified in inferring the actual 

 quality of mental processes in animals. For this reason he 

 objects to the term " comparative psychology" (216). There 

 is no doubt that great caution should be used in regarding the 

 quality of a human conscious process as identical with the 

 quality of the corresponding process in the animal mind. For 

 example, we might say with a fair degree of assurance that 

 an animal consciously discriminates between light and 

 darkness ; that is, receives conscious impressions of different 

 quality from the two, yet the mental impression produced by 

 white light upon the animal may be very different frornjfee 

 sensation of white as we know it, and the impression procmced 

 by the absence of light very different from our sensation of 

 black. Black and white may, for all we know, depend for 

 their quality upon some substance existing only in the human 

 retina. 



A second precaution concerns the simplicity or complexity 

 of the interpretation put upon animal behavior. Lloyd 

 Morgan, in his " Introduction to Comparative Psychology," 

 formulated a conservative principle of interpretation which 

 has often been quoted as " Lloyd Morgan's Canon." The 

 principle is as follows : " In no case may we interpret an action 

 as the outcome of the exercise of a higher psychical faculty, 

 if it can be interpreted as the outcome of the exercise of one 

 which stands lower hi the psychological scale" (280, p. 53). 



