T.] MR. DARWIN'S CRITICS. 249 



unaccompanied by consciousness. In other words, if 

 there is no ground for believing that a clog thinks, 

 neither is there any for believing that he feels. 



As is well known, Descartes boldly faced this dilemma, 

 and maintained that all animals were mere machines and 

 entirely devoid of consciousness. But he did not deny, 

 nor can anyone deny, that in this case they are reason- 

 ing machines, capable of performing all those operations 

 which are performed by the nervous system of man 

 when he reasons. For even supposing that in man, 

 and in man only, psychosis is superadded to neurosis 

 the neurosis which is common to both man and 

 animal gives their reasoning processes a fundamental 

 unity. But Descartes's position is open to very serious 

 objections, if the evidence that animals feel is insuf- 

 ficient to prove that they really do so. What is the 

 value of the evidence which leads one to believe that 

 one's fellow-man feels ? The only evidence in this 

 argument of analogy, is the similarity of his structure 

 and of his actions to one's own. And if that is good 

 enough to prove that one's fellow-man feels, surely it is 

 good enough to prove that an ape feels. For the differ- 

 ences of structure and function between men and apes are 

 utterly insufficient to warrant the assumption, that while 

 men have those states of consciousness we call sensations, 

 apes have nothing of the kind. Moreover, we have as 

 good evidence that apes are capable of emotion and 

 volition as we have that men other than ourselves are. 

 But if apes possess three out of the four kinds of states 

 of consciousness which we discover in ourselves, what 

 possible reason is there for denying them the 'fourth ? 

 If they are capable of sensation, emotion, and volition, 

 why are they to be denied thought (in the sense of 

 predication) \ 



No answer has ever been given to these questions. 



