128 PROBLEMS OF EVOLUTION 



presses onward, those that, passing all other roads, keep on 

 in a particular direction will at length form a species guided 

 by instincts that seldom swerve. Thus evolution proceeds by 

 Natural Selection, but at the cost of an enormous sacrifice 

 of life, even after instincts come in to reduce it. At the 

 higher levels there is an intensification of Natural Selection, 

 but the waste of indiscriminate destruction in a great degree 

 comes to an end. Intelligence and plasticity are the order 

 of the day. The monkey is a good representative of the new 

 system : the caterpillar with his one accomplishment, of the 

 old. Intelligence enables those who have it to make them- 

 selves at home where the creature of instinct would perish. 

 They pass their youth in playing and imitating and thus gain 

 a versatility that protects them amid the shocks of circum- 

 stance. They have merit of a kind that must make itself felt. 

 Though they have marked tendencies, strong likes and dislikes, 

 yet they have withal a certain saving pliancy and elasticity. 

 And greater pliancy in its component individuals leads, as 

 I have tried to show in this section, to greater adaptability 

 in the species. The result is that among the higher plastic 

 classes of animals evolution proceeds more rapidly. 



But obviously the quickening up of evolution is not all. The 

 individual gains in importance. He improves his powers, is able 

 to face a change of environment that otherwise would have been 

 fatal. He makes an environment for his young in which intelli- 

 gence can be developed : he chooses the environment which they 

 shall have when out of the nursery and so decides to some ex- 

 tent what qualities shall be the winning qualities in life. In fact 

 he is beginning to take the helm and steer the species. Or 

 we may put it in this way : when the individuals of one genera- 

 tion decide the environment in which the next shall grow up, 

 selection ceases to be purely natural : it is in part artificial. 



