n.l INTELLIGENCE AND INSTINCT 139 



little, even supposing they are remembered at all; but the 

 steam-engine, and the procession of inventions of every 

 kind that accompanied it, will perhaps be spoken of as we 

 speak of the bronze or of the chipped stone of pre-historic 

 times: it will serve to define an age. 1 If we could rid our- 

 selves of all pride, if, to define our species, we kept strictly 

 to what the historic and the prehistoric periods show us 

 to be the constant characteristic of man and of intelli- 

 gence, we should say not Homo sapiens, but Homo faber. 

 In short, intelligence, considered in what seems to be its 

 original feature, is the faculty of manufacturing artificial 

 objects, especially tools to make tools, and of indefinitely 

 varying the manufacture. 



Now, does an unintelligent animal also possess tools 

 or machines? Yes, certainly, but here the instrument 

 forms a part of the body that uses it; and, correspond- 

 ing to this instrument, there is an instinct that knows how 

 to use it. True, it cannot be maintained that all instincts 

 consist in a natural ability to use an inborn mechanism. 

 Such a definition would not apply to the instincts which 

 Romanes called "secondary"; and more than one "pri- 

 mary" instinct would not come under it. But this defi- 

 nition, like that which we have provisionally given of 

 intelligence, determines at least the ideal limit toward 

 which the very numerous forms of instinct are traveling. 

 Indeed, it has often been pointed out that most instincts 

 are only the continuance, or rather the consummation, 

 of the work of organization itself. Where does the activity 

 of instinct begin? and where does that of nature end? We 

 cannot tell. In the metamorphoses of the larva into the 

 nymph and into the perfect insect, metamorphoses that 



1 M. Paul Lacombe has laid great stress on the important influence 

 that great inventions have exercised on the evolution of humanity (P. 

 Lacombe, De I'histoire considere'e comme science, Paris, 1894. See, in 

 particular, pp. 168-247). 



