264 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



for the non-existence of what is not, with the sufficient 

 reason of what is. 



Natural selection has a certain important logical bearing 

 on systematics, as a science of the future, which has scarcely 

 ever been alluded to. Systematics of course has to deal 

 with the totality of the possible, not only of the actual 

 diversities ; it therefore must remember that more forms 

 may be possible than are actual, the word " possible ' 

 having reference in this connection to originating, not to 

 surviving. Moreover, systematics is concerned not only 

 with what has been eliminated by selection, but also with 

 all that might have originated from the eliminated types. 

 By such reasoning natural selection gains a very important 

 aspect but a logical aspect only. 



FLUCTUATING VARIATION THE ALLEGED CAUSE OF ORGANIC 



DIVERSITY 



The second doctrine of dogmatic Darwinism states that 

 all the given diversities among the organisms that natural 

 selection has to work upon are offered to natural selection 

 by so-called fluctuating variation ; that is, by variation as 

 studied by means of statistics. This sort of variation, 

 indeed, is maintained to be indefinite in direction and 

 amount, at least by the most conservative Darwinians ; it 

 has occasionally been called a real differential ; in any case 

 it is looked upon as being throughout contingent with 

 regard to some unity or totality ; which, of course, is not to 

 mean that it has not had a sufficient reason for occurring. 



It could hardly be said to be beyond the realm of 

 possibility that such differences among organic species as 



