ii INTELLIGENCE AND INSTINCT 145 



tion of images, there are some that we do not hesitate 

 to call intelligent : foremost among them are those that 

 bear witness to some idea of manufacture, whether the 

 animal itself succeeds in fashioning a crude instrument 

 or uses for its profit an object made by man. The 

 animals that rank immediately after man in the matter 

 of intelligence, the apes and elephants, are those that 

 can use an artificial instrument occasionally. Below, 

 but not very far from them, come those that recognize 

 a constructed object : for example, the fox, which 

 knows quite well that a trap is a trap. No doubt, there is 

 intelligence wherever there is inference ; but inference, 

 which consists in an inflection of past experience in the 

 direction of present experience, is already a beginning 

 of invention. Invention becomes complete when it is 

 materialized in a manufactured instrument. Towards 

 that achievement the intelligence of animals tends as 

 towards an ideal. And though, ordinarily, it does not 

 yet succeed in fashioning artificial objects and in 

 making use of them, it is preparing for this by the very 

 variations which it performs on the instincts furnished 

 by nature. As regards human intelligence, it has not 

 been sufficiently noted that mechanical invention has 

 been from the first its essential feature, that even to-day 

 our social life gravitates around the manufacture and 

 use of artificial instruments, that the inventions which 

 strew the road of progress have also traced its direction. 

 This we hardly realize, because it takes us longer to 

 change ourselves than to change our tools. Our in 

 dividual and even social habits survive a good while 

 the circumstances for which they were made, so that 

 the ultimate effects of an invention are not observed 

 until its novelty is already out of sight. A century 

 has elapsed since the invention of the steam-engine, 



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