38 THE LESSON OF EVOLUTION 



ciently developed, animals showed the commencement 

 of a psychological evolution of mind. At first this 

 latest development of evolution was entirely intel- 

 lectual, and was chiefly employed in the preservation 

 of the race. At a later stage a higher development took 

 place and a moral evolution commenced. Physical 

 evolution, biological evolution, and psychological evolu- 

 tion are still going on. So far as the earth is con- 

 cerned, physical evolution has reached, probably it has 

 passed, its optimum ; for the earth cannot in the future 

 be better fitted for the development of life than it 

 is now. Biological evolution has also reached its 

 optimum in man, whose body has been practically 

 stationary since the middle of the pleistocene period, 

 and cannot now be affected by natural selection. 

 Indeed, ever since the beginning of the neolithic age 

 man has been engaged in combating natural selection 

 by endeavouring to alter the surrounding conditions 

 to suit himself. This he does by making artificial 

 warmth, building houses, making clothes, and cultivat- 

 ing land. 



Psychological evolution, however, has not yet 

 reached its optimum. The development of the human 

 mind is but in its infancy. Man's origin dates back 

 only some tens of thousands of years, while he has 

 several millions of years before him. During that 

 time it is impossible to predict what will happen ; but 

 so long as the external conditions are favourable for 

 the working of the brain, we may feel sure that 

 psychological evolution will continue. 



Any other kind of evolution besides those of 

 matter, life, and mind is unimaginable, because we 

 know of nothing else on the earth to evolve. The 



