vi INSTINCT 71 



On the other hand, men do perform actions without know- 

 ing the reason why, and come at the reason afterwards by 

 reflection. In short, instinct is a "vera causa." We know 

 it among ourselves. Innate conception is not a "vera 

 causa." To impute it to an animal is to infer, on the 

 ground of actions similar to those of man, an intellectual 

 method opposed to those of man. 



j3. Instinct and Intelligence are opposed in the nature 

 of their contents. 



If we were to regard as the work of thought actions 

 which we usually attribute to instinct, we should have to 

 impute to the animals which perform them a marvellous 

 capacity for intricate scheming and planning. A single 

 instance will be a sufficient illustration. 



" The caterpillar of the emperor moth spins at the upper 

 extremity of its cocoon a double arch of stiff bristles, held together 

 above only by a few fine threads. The cocoon, i.e. y opens at the 

 very least pressure from within, but is able to resist quite strong 

 pressure from without. Autenrieth writes of this in his Amichten 

 uber Natur- und Seelenleben : ' If the caterpillar acted from reflec- 

 tion and with understanding, it must, on human analogy, have 

 pursued the following train of thought : that it had reached its 

 chrysalis stage, and would therefore be at the mercy of any un- 

 lucky accident, without possibility of escape, unless it took certain 

 precautionary measures in advance ; that it would have to issue 

 from its cocoon as imago without having organs or strength for 

 breaking through the cover it had spun as caterpillar, and without 

 possessing any secretion, like other insects, which would, if 

 emitted, eat through the threads of silk ; and that consequently, 

 unless it took care to provide as caterpillar a convenient exit from 

 its cocoon, it must certainly come to a premature end in im- 

 prisonment. On the other hand, it must have clearly recognised 

 during its work upon the cocoon that, in order to have free egress 

 as imago, it would only be necessary to construct an arch which 

 could resist attacks from without while opening easily from 

 within j and that these conditions would be fulfilled if the arch 

 were made of stiff threads, inclined together in the median line, 

 and with their ends left free. At the same time it must have 

 realised that the plan could be carried out if the silk employed for 

 the construction of the other parts of the cocoon were employed 

 with special care and skill at the upper end. Yet it could have 

 learnt nothing of all this from its parents.' " 1 . . . 



1 Wundt, Lectures on Human and Animal Psychology, pp. 391-392, 



