i897. COPE'S ''FACTORS OF EVOLUTION:' 41 



after mutation, generation after generation, developing in apparent 

 obedience to obvious physico-chemical or mechanical conditions, that 

 they incline to regard these conditions as causes. And if it be 

 suggested to them that the results they see may have been achieved 

 by the selection of adaptive variations from among a number of 

 promiscuous variations that were not adaptive, they ask why it is that 

 they do not find evidence of these numerous non-adaptive variations in 

 the rocks, when one would suppose that, on any hypothesis except 

 that of definite variation, such forms must have been the more 

 abundant of the two. It is useless to reply to them that the non- 

 adaptive variations in each generation were killed off when young, and 

 so, even if fossilised, are practically undistinguishable ; because they 

 will reply with abundant proof that the adaptive characters chiefly 

 appear in the adult stages of the organism, possibly only in its senile 

 stages, and so are incapable of coming under the action of natural 

 selection during the early undifferentiated stages. How the conversa- 

 tion might continue does not much matter, for it is obvious that it has 

 reached a point beyond which all must be speculation. The facts on 

 which the palaeontologist relies, the facts that Professor Cope adduces 

 with such wealth of knowledge, are strong presumptive evidence in 

 favour of his second thesis. But they are not proof. 



" Chapter VII. — Natural Selection " is included in this part, not 

 because the author regards natural selection as a cause of variation, 

 but because he wishes to controvert that view. It is often stated in 

 the writings of those who are not strict Neo-Darwinians, that some, at 

 least, of the Neo-Darwinians regard natural selection as a cause of 

 -variation. If this be so, Professor Cope is surely right in affirming 

 such Neo-Darwinians to be in error. " A selection cannot be the 

 cause of those alternatives from which it selects." To state that 

 natural selection may preserve the character of variability is another 

 matter ; for variability is just as much a character of some organisms 

 as fixity is a character of others, and this without reference to the 

 -environment ; and since variability is a character that may work 

 good or ill to an organism, it inevitably falls under the action of 

 selection. Apart from this, is there not a slight misunderstanding 

 here, due perhaps to a lax use of the term " natural selection ? " 

 Whereas " selection " means selection and no more, the stereotyped 

 phrase " natural selection" has come to imply the whole process that 

 forms the fundamental conception of Darwinism. For evolution to 

 take place through this process, we must postulate: — first, variation in 

 the off"spring ; secondly, variation in the environment ; thirdly, selec- 

 tion of such variations in the offspring as are in harmony with the 

 variation in the environment. It is this whole series that results in 

 change — change which is definite in kind, and which influences many 

 individuals in the same way. In short, this is " the origin of species 

 by natural selection." 



However elementary the above exposition may seem to some, it 



