10 Chapter L 



performs an action with or without consciousness? it 

 is always precarious in natural sciences to introduce an 

 element which cannot be examined or identified em- 

 pirically, as a constituent part of any notion." How- 

 ever, Ziegler overlooked the fact, that in critical 

 discussions on the psychic activities of animals we are 

 forced to start from the analogy of the same activities 

 in man ; otherwise our knowledge of animal psychology 

 would be very limited. In our own psychic life, how- 

 ever, we know from experience the difference between 

 intentional and unintentional actions, a difference 

 which is equally characteristic of their exterior mani- 

 festations. But as this is so clearly the case in the 

 psychic life of man, comparative psychology is forced 

 to extend the distinction between intentional and 

 unintentional actions to the psychic life of animals. 

 Nor is this the only reason for doing so. For without 

 this distinction animal psychology would merely become 

 a department of nerve physiology. According to Ziegler 

 the difference between instinctive and intelligent action 

 consists in the fact that the former depends on hereditary 

 nerve mechanisms, and the latter on the individual 

 experience of single beings. Yet, reflex activities depend 

 equally well on hereditary nerve dispositions; hence, 

 according to Ziegler's definition, the difference between 

 instinct and reflex activity would altogether disappear. 

 Therefore it cannot be adopted. It is true, the possibility 

 of hereditary transmission of the instinctive associations 

 of perceptions as was long ago the doctrine of Aris- 

 totelian Philosophy is one of the distinctive features of 

 instinct in contradistinction to intelligence; but it does 

 not constitute the only, and much less the essential 



