Poulton. ] 384 [May 16, 
beginning if we push our inquiries far enough. In attempting 
this, we are carried: to those remote times in which the ancestors 
of vertebrates arose. Upon these forms we can do no more than 
speculate, but it is at any rate impossible to prove that four bud- 
like projections from the body may not have been useful, from 
their very beginning, to a slender worm-like animal in pushing 
its way through mud or thick weeds. Dr. E. B. Tylor has told 
me that he believes that the same thing holds with regard to 
human weapons. He said that, in examining ancient weapons, 
he was often struck with the fact that a weapon or implement 
had ultimately turned out to be so very much more useful for a 
new purpose rather than that for which it was originally formed. 
Here, then, one origin apparently accounts for several forms of 
implement. 
Another objection raised against natural selection is that a 
selective cause is never a true cause. Professor Cope means to 
imply that when he speaks of the ‘Origin of the fittest.” But 
Darwin’s argument on this point is perfectly sufficient. He says 
that when a man drops iron into sulphuric acid, he does not 
originate the chemical force that operates, but he may be fairly 
said to make sulphate of iron. So natural selection does not 
itself originate the factors upon which it depends, but it is so 
essential to the result that it may be fairly looked upon as the 
true cause (at that level of causation). In Galton’s work we 
have a most complete inquiry into human variation and its inheri- 
tance, and he shows us that such variation by itself, unguided by 
selection, can never advance to anything. Even if you start with 
ancestors who are remarkable for any intellectual or structural 
feature, their descendants, although some of them may partake 
of their parents’ peculiarities, sometimes even to an increased 
extent, will ultimately return to the pattern of the race. There 
is always a ‘‘recession towards mediocrity.” Hence, unguided 
variation can never explain the ‘‘origin of the fittest.” Such a 
view is entirely contradicted by the results of Galton’s researches. 
Any marked change in the direction of fitness can only become a 
character of the species by accumulation through many genera- 
tions, and this can only take place by natural selection. Varia- 
\ tion unguided by selection can never advance on the increase of 
\ fitness present among the individuals of a single generation ; and 
vce these improvements, if relatively marked, can never become 
ee 
