The Evidence of Mind 31 



speak of a " mechanism" as forming an "elemental com- 

 ponent" in " psychic phenomena," but these points may be 

 passed over. The power to learn by individual experience 

 is the evidence which Romanes, Morgan, and Loeb will 

 accept as demonstrating the presence of mind in an animal. 



Does the absence of proof that an animal learns by expe- 

 rience show that the animal is unconscious? Romanes is 

 careful to answer this question in the negative. "Because a 

 lowly organized animal," he says, "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 evi- 

 dence of the fact " (364, p. 3). Loeb, on the other hand, writes 

 as if absence of proof for consciousness amounted to disproof, 

 evidently relying on the principle of parsimony, that no 

 unnecessary assumptions should be admitted. "Our crite- 

 rion," he remarks, "puts an end to the metaphysical ideas 

 that all matter, and hence the whole animal world, possesses 

 consciousness" (243, p. 13). If learning by experience be 

 really a satisfactory proof of mind, then its absence in certain 

 animals would indeed prevent the positive assertion that all 

 animals are conscious ; but it could not abolish the possibility 

 that they might be. Such a possibility might, however, be 

 of no more scientific interest than any one of a million wild 

 possibilities that science cannot spare time to disprove. But 

 we shall find that learning by experience, taken by itself, is 

 too indefinite a concept to be of much service, and that when 

 defined, it is inadequate to bear the whole weight of proving 

 consciousness in animals. Such being the case, the possi- 

 bility that animals which have not been shown to learn may 

 yet be conscious acquires the right to be reckoned with. 



The first point that strikes us in examining the proposed 



