﻿Characters as Adaptive and Specific. 249 



great majority of naturalists follow Darwin by answering 

 it in the affirmative. And this is enough to show the 

 only point which we need at present concern ourselves 

 with showing — viz. that the question is, at the least, 

 an open one. For as long as this question is an open 

 one among believers in the theory of natural selection, 

 it must clearly be an unwarrantable deduction from 

 that theory, that all species, and a fortiori all specific 

 characters, are necessarily due to natural selection. 

 The deduction cannot be legitimately drawn until 

 the possibility of any other cause of specific modifica- 

 tion has been excluded. But the bare fact of the 

 question as just stated being still and at the least an 

 open question, is enough to prove that this possibility 

 has not been excluded. Therefore the deduction must 

 be, again on this ground alone (C), unwarrantable. 



Such are my several reasons — and it is to be 

 observed that they are all independent reasons — foi 

 concluding that it makes no practical difference to 

 the present discussion whether or not we entertain 

 Heredity as a criterion of specific distinction. Seeing 

 that our species- makers have paid so little regard to 

 this criterion, it is neither absurd nor preposterous 

 to have adduced, in the preceding chapter, the facts 

 of climatic variation. On the contrary, as the defini- 

 tion of " species " which has been practically followed 

 by our species-makers in No. 3, and not No. 4, these 

 facts form part and parcel of our subject. It is per- 

 fectly certain that, in the vegetable kingdom at all 

 events, " a large proportional number " of specifically 

 diagnostic characters would be proved by experiment 

 to be (i somatogenetic " ; while there are numerous 



