ii.l INTELLIGENCE AND INSTINCT 137 



This rather narrow view of them has the advantage of 

 giving us an objective means of distinguishing them. In 

 return, however, it gives us, of intelligence in general 

 and of instinct in general, only the mean position above and 

 below which both constantly oscillate. For that reason 

 the reader must expect to see in what follows only a dia- 

 grammatic drawing, in which the respective outlines 

 of intelligence and instinct are sharper than they should 

 be, and in which the shading-off which comes from the 

 indecision of each and from their reciprocal encroachment 

 on one another is neglected. In a matter so obscure, 

 we cannot strive too hard for clearness. It will always be 

 easy afterwards to soften the outlines and to correct what 

 is too geometrical in the drawing — in short, to replace 

 the rigidity of a diagram by the suppleness of life. 



To what date is it agreed to ascribe the appearance 

 of man on the earth? To the period when the first 

 weapons, the first tools, were made. The memorable 

 quarrel over the discovery of Boucher de Perthes in the 

 quarry of Moulin-Quignon is not forgotten. The question 

 was whether real hatchets had been found or merely 

 bits of flint accidentally broken. But that, supposing 

 they were hatchets, we were indeed in the presence of 

 intelligence, and more particularly of human intelligence, 

 no one doubted for an instant. Now let us open a col- 

 lection of anecdotes on the intelligence of animals: we 

 shall see that besides many acts explicable by imitation 

 or by the automatic association 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 manu- 

 facture, whether the animal life succeeds in fashioning a 

 crude instrument or uses for its profit an object made by 

 man. The animals that rank immediately after man in 



