ASPECTS OF KINETIC EVOLUTION 285 



and the Darwinian doctrines were crystallized into formulae 

 which were believed to demonstrate evolution from the facts of 

 the struggle for existence and the survival of the fittest. 



PROVED FACTS. NECESSARY CONSEQUENCES. 



Rapid Increase of Organisms. "1 _ . . _ . 



m itvt ^ i-r j- -j i ox »• ^Struggle for Existence. 



1 otal Number of Individuals stationary. J 



Struggle for Existence. "i _ . , . . „. , 



TT b ° . , TT . . ^Survival of the Fittest. 



Heredity with Variation. J 



Survival of the Fittest. \ Changes of Organic 



Change of External Conditions. J Form. 



The earlier Darwinists were practical men and made the best 

 use of the facts as they knew them. Whether the facts they 

 regarded as proved would really be able to bring about evolution 

 in normally stationary species is a question which might still be 

 debated on philosophical grounds, like the fourth dimension of 

 space and other hypothetical problems. But for practical pur- 

 poses there is no need to reopen the discussion, since it is now 

 apparent that formulae like those quoted above leave out of 

 account a very important part of the facts of nature, the very 

 facts, as it happens, which are most potent in the development 

 of organic types. The evolution, if any, which the formula 

 would provide would certainly not be that found in nature. 



Scientific progress, at least in biology, does not follow the 

 lines of formal mathematics or logic, but depends on history and 

 human nature, like political and economic movements. It could 

 not be expected that the evidences of evolutionary processes 

 would be carefully weighed and correctly appreciated at a time 

 when the very idea of evolution was being assaulted as an im- 

 moral perversion of intellect. 



The best that could be done at the time was to drive the piles 

 of accepted inferences into the mud of ignorance. The struc- 

 ture reared on such a foundation could not be a permanent one, 

 but it has served to shelter a generation of students of nature, 

 and enabled them to prepare the foundations of a more secure 

 edifice of evolutionary doctrine based directly on ascertained 

 facts. 



