vin DARWINISM AND HOLISM 189 



achieved by the internal factor. The inner factor, Varia- 

 tion, is positive and creative, producing all the variations 

 which are the raw material for progress. The exter- 

 nal factor, Natural Selection, is essentially negative and 

 destructive, eHminating the harmful or less fit or use- 

 ful variations, and leaving the more fit or useful varia- 

 tions free play to continue and multiply, and in this 

 process fitting and adapting the individual to the char- 

 acter of its environment. As De Vries has phrased it, 

 the inner factor explains the arrival, and the external 

 factor the survival, of the fit or useful variation or 

 organism. 



Darwin's over-emphasis of the second or external factor 

 had one very unfortunate result: it directly and powerfully 

 reinforced and exaggerated the mechanistic conception of 

 the universe. The vera causa of organic change and progress 

 appeared to be Natural Selection, an external factor oper- 

 ating on organisms ab extra, in the same way as physical or 

 dynamical forces are impressed on bodies or their parts 

 from the outside. Mechanical analogies began to be applied, 

 and Evolution came to be looked upon as the mechanics of 

 organic development — Entwicklungsmechanik, as it has 

 been called by Wilhelm Roux. The whole tendency of 

 Darwinism has therefore been vastly to add to the domi- 

 nance of the mechanistic hypothesis, which has through it 

 come to extend its sway from the kingdom of matter to 

 that of life. What is more, the simplicity of the Darwinian 

 theory has helped to make, not only Evolution, but the 

 mechanical view of Evolution, common property. The mys- 

 tery of progress seemed to become quite simple and intelli- 

 gible on this theory. It all depended on the survival of the 

 fittest, and the survival of the fittest was so simple and clear 

 an idea, and one too so deeply rooted in our ordinary empiri- 

 cal experience, that it seemed all a matter of course which 

 had only to be pointed out by Darwin to be accepted by 

 everybody. The difficult part of the theory, the aspect of it 

 which even to Darwin had remained a mystery, the inner 

 creative factor of Variation, was ignored while Darwinism 



