CHAPTER II. 



INSTINCT AND INTELLIGENCE ACCORDING TO MODERN 

 ZOOLOGY. 



IN his above-mentioned essay Ziegler tries to explain 

 the difference between instinct and intelligence in the 

 following manner: "Those associations in the life of 

 animals are due to intelligence which spring from 

 impressions gained by individual sense perceptions; 

 those, however, which do not depend on individual 

 experience, are instinctive." This explanation, accord- 

 ing to which only those psychic actions of the animal 

 are said to be instinctive, which immediately arise from 

 hereditary dispositions, whilst all those which presup- 

 pose individual experience are due to intelligence, is, by 

 the way, not at all new. It might simply be styled the 

 animal psychology of modern zoology, especially since 

 the days of Charles Darwin. Let us therefore carefully 

 examine, whether this view of the question corresponds 

 to the demands of scientific psychology. 



What is meant by "hereditary instinct"? Complex 

 representations or combinations of certain affections with 

 certain impulses that are inherited complete ay such, 

 do not exist. 1 Only the psychic faculty, or the dis- 



*) We have previously proved that the assumption of innate, cogni. 

 tive images (species objective innatae), in order to explain instinct, is 

 highly improbable, even from a mere psychological standpoint ("Der 

 Trichterwickler," p. 154 flf.). It is still less probable from a zoological 

 (somatological) point of view- as every possible instinctive representation 

 would have to pre-exist in the embryonic disposition of the animal in a 

 definite, material part or element (whether it be an Id or a Determinant 

 of Weismann). 



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