146 THE DESCENT OF MAN, 



the wild plains of America, and on the isolated islands in 

 the PaciMc Ocean. At the present day civilized nations 

 are everywhere supplanting barbarous nations, excepting 

 where the climate opposes a deadly barrier; and they suc- 

 ceed mainly, though not exclusively, through their arts, 

 which are the products of the intellect. It is, therefore, 

 highly probable that with mankind the intellectual facul- 

 ties have been mainly and gradually perfected through 

 natural selection; and this conclusion is sufficient for our 

 purpose. Undoubtedly it would be interesting to trace the 

 development of each separate faculty from the state in 

 which it exists in the lower animals to that in which it 

 exists in man; but neither my ability nor knowledge per- 

 mits the attempt. 



It deserves notice that as soon as the progenitors of man 

 became social (and this probably occurred at a very early 

 period), the principal of imitation and reason and experi- 

 ence would have increased and much modified the intel- 

 lectual powers in a way, of which we see only traces in the 

 lower animals. Apes are much given to imitation, as are 

 the lowest savages; and the simple fact previously referred 

 to, that after a time no animal can be caught in the same 

 place by the same sort of trap, shows that animals learn by 

 experience and imitate the caution of others. Now, if some 

 one man in a tribe, more sagacious than the others, invented 

 a new snare or weapon, or other means of attack or defense, 

 the plainest self-interest, without the assistance of much 

 reasoning power, would prompt the other members to imi- 

 tate him; and all would thus profit. The habitual practice 

 of each new art must likewise in some slight degree 

 strengthen the intellect. If the new invention were an 

 important one, the tribe would increase in number, spread, 

 and supplant other tribes. In a tribe thus rendered more 

 numerous there would always be a rather greater chance of 

 the birth of other superior and inventive members. If 

 such men left children to inherit their mental superiority, 

 the chance of the birth of still ntore ingenious members 

 would be somewhat better, and in a very small tribe decid- 

 edly better. Even if they left no children, the tribe would 

 still include their blood-relations; and it has been ascer- 

 tained by agriculturists* that by preserving and breeding 



* I have given instances in my " Variation of Animals under Dq- 

 Wjestication," vol. ii, p. 196. 



