374 Darwin, and after Darwin. 
The threc objections to which I allude are, (1) that 
a large proportional number of specific, as well as 
of higher taxonomic characters, are seemingly useless 
characters, and therefore do not lend themselves to 
explanation by the Darwinian theory; (2) that the 
most general of all specific characters—viz. cross- 
infertility between allied species—cannot possibly 
be due to natural selection, as is demonstrated by 
Darwin himself; (3) that the swamping effects of 
free intercrossing must always render impossible by 
natural selection alone any evolution of species in 
divergent (as distinguished from serial) lines of 
change. 
These three objections have been urged from time 
to time by not a few of the most eminent botanists 
and zoologists of our century; and from one point 
of view I cannot myself have the smallest doubt that 
the objections thus advanced are not only valid in 
themselves, but also by far the most formidable 
objections which the theory of natural selection has 
encountered. From another point of vicw, however, 
I am equally convinced that they all admit of ab- 
solute annihilation. This strong antithesis arises, as 
I have said, from differences of standpoint, or from 
differences in the view which we take of the theory of 
natural selection itself. If we understand this theory 
to sct forth natural selection as the sole cause of 
organic evolution, then all the above objections to the 
theory are not merely, as already stated, valid and 
formidable, but as I will now add, logically insur- 
mountable. On the other hand, if we take theory 
to consist merely in setting forth natural selection as 
a factor of organic evolution, even although we be- 
