All Sufficiency of Natural Selection 193 



view that natural selection by itself is sufficient to account 

 for the transformation of species, we shall bring forward 

 only a very small number. For we believe it worth 

 while to limit ourselves to the most characteristic and 

 certain ones, which serve better than the others as an 

 indirect support for the Lamarckian theory. And so 

 much the more since in the case of many objections dis- 

 cussion is idle. For and this may be said once for all 

 if our adversary adopts the complete sufficiency of 

 natural selection both as his thesis and as the ground 

 for the defense of this thesis, naturally it will be very 

 difficult, indeed, often quite impossible for us to carry 

 on the contest from a purely logical standpoint. 



Candidly one could wish that Weismann would prove 

 this omnipotence of natural selection by some facts. But 

 he has still to furnish this proof. For, as we have seen, 

 he has limited himself to showing that among the various 

 hypotheses which have been devised to give account for 

 certain special formations, natural selection is the one 

 which fulfills this purpose relatively best. 



But when once our adversary sets up this almighti- 

 ness of natural selection as an axiom, to be employed 

 at need as thesis or as the support of the thesis, it will 

 then be very difficult, we repeat, in most cases to point 

 out any contradiction in his tenets, which is the only 

 means by which a logical refutation can proceed and 

 reach any result. In other words, if in order to demon- 

 strate the complete sufficiency of selection Weismann 

 starts off with the supposition that natural selection is 

 omnipotent, how can one by pure reasoning convict him 

 of error? 



And in fact: One investigator offers the objection 

 that fortuitous variations even though they are useful 



