THE DARWINIAN REVOLUTION BEGINS 131 



beginning of the century. This explains why Mr. 

 Darwin's success was so rapid and complete, and it also 

 explains why he came so near being anticipated.' To 

 put it briefly, a priori, creation is from the very first 

 unbelievable; but, as a matter of evidence, Lamarck 

 failed to make evolution comprehensible, or to give a 

 rationale of its mode of action, while Darwin's theory 

 of natural selection succeeded in doing so for those who 

 awaited a posteriori proof. Hence Darwin was able to 

 convert the world, where Lamarck had only been able 

 to stir up enquiry among the picked spirits of the 

 scientific and philosophical coterie. Therein lies the 

 true secret of his rapid, his brilliant, and his triumphant 

 progress. He had found out not only that it was so, 

 but how it was so, too. In Aristotelian phrase, he had 

 discovered the TTWS as well as the on. 



