i MENTAL EVOLUTION 9 



ism to the conditions of the environment. They are in 

 man on a very large and complex scale what the respiratory 

 or muscular mechanism is on a smaller scale. As these are 

 arranged to secure a permanent supply of oxygen, the 

 maintenance of an even bodily temperature and so forth, 

 so the nervous system is arranged to secure such action as 

 will, by however circuitous a route, feed, clothe and pre- 

 serve the organism, cause it to produce children and rear 

 them. The machinery gets more complex, but it is still 

 machinery arranged to secure the ultimate object of the 

 survival of the species. Mind and the world of mind, 

 society, government, the churches, religion, law, are pro- 

 ducts which have grown up under the pressure of the 

 constant and supreme biological need, and exist only to 

 serve that need. They are evolved to meet the require- 

 ments as an aquatic species on taking to the land is held 

 to have evolved lungs, and if their vital function ceases 

 they atrophy as the eyes of a cave-dwelling animal atrophy. 

 Their end and object, their causation, is not in themselves 

 but in the more fundamental biological conditions from 

 which they are thrown up. It must be added that these 

 conditions seem at a vital point to be positively hostile to 

 certain of the effects of mind-development. For it is a 

 general condition of the good adaptation of a species to 

 an environment that the weaker members of the species 

 should be persistently weeded out. ' But with the expan-" 

 sion of mental life come affections and sympathies, and later 

 on religious and ethical sentiments inculcating mutual aid, 

 discouraging the struggle of each for himself and enjoining 

 the preservation of many who but for such assistance 

 would go under in the life-storm. The rise of such senti- 

 ments is from the strictly selectionist point of view a case 

 of the emergence of a functionally noxious variation which 

 must be stamped out if the human species is to survive, 

 and the strict spirit of biology has in consequence waged 

 war for a couple of generations on such schemes of social 

 and political amelioration as tend to peace and equity 

 between nations, co-operation between classes, and mercy 

 and tenderness for the weaker brethren. It is however 

 only fair to say that the resulting contradiction between 



