4 INTRODUCTION 



we could never feel much confidence in any conclusions as 

 to the kind of conscious states which make up their mental 

 life. We may be asked, in what way do we know these 

 animals have conscious states at all? May they not be as 

 Descartes has considered all animals below man, merely 

 unconscious automata? The question throws us back upon 

 what criterion we adopt of consciousness and upon this 

 subject the opinions of psychologists present us with no end 

 of differences. 



The criterion of consciousness which is perhaps most 

 widely adopted at the present time is the ability to learn by 

 experience, or associative memory. Among those who have 

 adopted this standpoint may be mentioned Bethe, Loeb 

 and Bohn. Romanes and Lloyd Morgan, while they 

 recognize that ability to learn is indicative of the presence of 

 consciousness, hesitate to draw the conclusion that con- 

 sciousness is absent in those animals which are devoid of 

 associative memory. In his work on Animal Intelligence 

 Romanes states that "because a lowly organized animal 

 does not learn by its own individual experience, we may 

 not therefore conclude that in performing its natural or 

 ancestral adaptations to appropriate stimuli consciousness, 

 or the mind element, is wholly absent; we can only say that 

 this element, if present, reveals no evidence of the fact." 

 Lloyd Morgan writes likewise in a guarded manner : " When 

 we see that a chick, for example, pecks at first at any small 

 object, it is difficult to say, on these grounds, whether it is 

 a sentient animal or an unconscious automaton; and if it 

 continued to behave in a similar fashion throughout life, 

 our difficulty would still remain. But when we see that 

 some objects are rejected while others are selected, we infer 

 that consciousness in some way guides its behavior. The 

 chick has profited by experience. But even this is only 



