SFUJVCJB AND DARWIN. 821 



explanation of tlie origin of species. Darwin's discovery con- 

 verted them en hloc. It was easy to understand, by means of the 

 clew he afforded, not merely that organisms had been naturally 

 evolved from simple primitive forms, but also lioiv and icliy they 

 had been so evolved. Darwin's great work, then, consisted in 

 this that he made credible a theory which most people before 

 him had thought incredible ; that he discovered a tenable modus 

 operandi for what had before been rather believed or surmised 

 than definitely imagined. 



I do not mean to say that Darwin did no more than this. He 

 supplied the great key of natural selection ; but he also added 

 much in other ways to the doctrine, especially in the direction of 

 piling up facts and meeting objections. His work had thus a 

 double value. On the one hand, it is not probable that the gen- 

 eral biological public would have been converted to evolutionism 

 half so quickly if it had not been for the enormous mass of con- 

 firmatory evidence adduced by Darwin. In the second place, even 

 those who, like Spencer, were already evolutionists evolutionists 

 in fiber, incapable of taking any supernaturalist view of the uni- 

 verse in which they lived gladly availed themselves of Darwin's 

 discovery of natural selection, as an explanation of one important 

 set of features in organic evolution, thitherto most imperfectly 

 and inadequately explained. Or, let us put it another way. 

 From the point of view of contribution to thought, it is natural 

 selection that forms Darwin's great glory. But from the point 

 of view of mere effective persuasion, it is the weight of evidence 

 he brought up in favor of the older principle of descent with 

 modification that told and still tells with the average mind. 

 Hence it has happened, and perhaps will always happen, that 

 Darwin has received more credit for that part of his theory 

 which was not of his own invention than for that part of which 

 he can justly claim the almost exclusive glory. Almost, I say, 

 because the modifying adverb is demanded by justice to Mr. 

 Alfred Russel Wallace, whose partial coincidence with Darwin 

 in the discovery of natural selection now needs no advertisement. 



As thinker, then, it is on natural selection as a vera causa 

 of specialization and adaptation among plants and animals that 

 Darwin most securely rests his claim to celebrity. As prophet 

 and apostle, on the other hand, it must be frankly admitted that 

 he ranks first as a preacher of organic but only of organic 

 evolution. In this respect, his importance, in England especially, 

 can hardly be overrated. For it is a peculiarity of the practical 

 English mind that it is more moved by a vast array of evidence, 

 a serried mass of cumulative instances, than by any possible 

 cogency of logical reasoning. Darwin's own mind was in this 

 way intensely English. He piled up fact after fact, added case 



