264 THE ASCENT OF MAN 



being, observe the r61e it plays in Nature. The 

 object of the Survival of the Fittest is to produce 

 fitness. And it does so both negatively and posi- 

 tively. In the first place it produces fitness by 

 killing off the unfit. Without the rigorous weeding 

 out of the imperfect the progress of the world had 

 not been possible. If fit and unfit indiscriminately 

 had been allowed to live and reproduce their kind, 

 every improvement which any individual might 

 acquire would be degraded to the common level in 

 the course of a few generations. Progress can only 

 start by one or two individuals shooting ahead of 

 their species ; and their life-gain can only be con- 

 served by their being shut off from their species 

 — or by their species being shut off from them. 

 Unless shut off from their species their acquisition 

 will either be neutralized in the course of time 

 by the swamping effect of inter-breeding with the 

 common herd, or so diluted as to involve no real 

 advance. The only chance for Evolution, then, is 

 either to carry off these improved editions into 

 " physiological isolation," or to remove the unim- 

 proved editions by wholesale death. The first of 

 these alternatives is only occasionally possible ; the 

 second always. Hence the death of the unevolved, 

 or of the unadapted in reference to some new and 

 higher relation with environment, is essential to 



