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 
