22 DARWINISM TO-DAY. 



at all shared by the biologists themselves. Biological science 

 contains much that is proved and certain; but also much 

 that is nothing more than working hypothesis, provisional 

 theory, and anticipatory generalisation. As the proved part 

 is largely of the nature of facts of observation, isolated and 

 unrelated, and the unproved part is composed of the large 

 and sweeping generalisations, the plausible, provisional ex- 

 planations, such as the various theories of heredity, of the 

 results of struggle, of the development of mutual aid, etc., 

 that is, is exactly the sort of material that the sociologist 

 needs to weave into his biological foundations for the 

 sociologic study of man, it is exactly this unproved part of 

 biology that the searching sociologist carries home with him 

 from his excursions into the biological field. The recapitula- 

 tion theory looms up large and familiar in biological soci- 

 ology ; it is mostly discredited in biology. The inheritance 

 of acquired characters serves as basis for much sociology ; 

 most biologists believe it impossible. The selection theories 

 are gospel to some sociologists ; they are the principal moot 

 points in present-day biology. And so on. Biology is not 

 yet come to that stage in its development where it can offer 

 many solidly founded generalisations on which other sciences 

 can build. The theory of descent is one such safe great 

 generalisation ; but perhaps Darwinism is not another. At 

 least many scholars do not believe that it is. 



APPENDIX. 



1 For the insects alone entomologists have estimated, on a basis 

 of the numbers of new species being annually found and described, 

 and on the basis of the degree to which the entomological explora- 

 tion of the earth has been carried, that over two million species 

 must be in present existence. 



2 See H. F. Osborn's "From the Greeks to Darwin" (1895) for a 



careful history of the unfolding of the descent idea; 

 scent theory, see a ^ so Edgar Dacque. "Der Descendenzgedanke und 



seine Geschichte," 1903 ; also Carus, J. V., "Geschichte 

 der Zoologie bis auf J. Miiller und C. Darwin," 1872; also Clodd, 



