Examination of Some Objections. 71 



genuine intelligence, the power of logical thought. 

 Therefore scholastic psychology cannot be held respon- 

 sible for these results. Our attitude towards modern 

 animal psychology rests, on the contrary, on an un- 

 prejudiced, critical examination of biological facts, 

 which forces us to uphold an essential difference be- 

 tween instinct and intelligence, between the psychic fac- 

 ulties of man and animals. 



The second point of Ziegler's reply is, that no natu- 

 ralist can tell how much self-consciousness accompanies 

 the psyhic actions of animals, and that it is impossible 

 to establish an essential difference between their psychic 

 faculties and those of man. If naturalists had no other 

 source of knowledge than what they see, feel, hear and 

 smell, then this difficulty would be to the point. But 

 this supposition annihilates any and every reasonable 

 investigation of nature. Naturalists have not only 

 sense faculties, but also an intellect, with which they 

 must infer the causes of facts from their external ap- 

 pearance. This principle is theoretically acknowledged 

 and practically followed by all naturalists in all branches 

 of science. Therefore, it must also hold goocl for com- 

 parative animal psychology. If animals do not mani- 

 fest activities which demand the assumption of self- 

 consciousness, we are not allowed to ascribe it to them, 

 because simpler causes explain the phenomena; and if 

 the assumption of self-consciousness contradicts other 

 activities, we must say that animals have none. Other- 

 wise we would act uncritically and not as reasoning 

 naturalists. But this is identical with the assertion of 

 an essential difference between the psychic faculties of 

 man and those of the animal. 



