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accepting it by the theological objection that it appeared to substitute 
the action of a physical force for the direct action of the Deity. In 
France, where ideas not of French origin are very apt to be but 
slowly apprehended, the opposition to the Newtonian theory was not 
silenced till 1759, when Clairaut and Lalande, by calculating the 
retardation of Halley’s comet, furnished such crucial proof as could 
not possibly be overcome. At this time Newton had been thirty-two 
years in his grave ; seventy-two years had elapsed since the publica 
tion of the Princiftia, and ninety-four since the hypothesis was first 
definitely conceived{Darwinism and other Essays, ftp. 1-2.) 
Mr. Wallace asserts that new facts fit in satisfactorily 
with the theory of Natural Selection, but since he wrote his 
Contributions to the Theory of Natural Selection, there have 
not been wanting experts who contend that certain facts 
can hardly be reconciled with the theory of Natural 
Selection ; and it is not too much to say that a reaction 
against Pure Darwinism, if not against Natural Selection, 
has already set in. 
Mr. Wallace pleads in favour of the doctrine of Natural 
Selection “ the evidence of necessity.” He meets the 
objection, that we have no direct evidence for the action of 
this selecting power in nature, thus :— 
1,1 But it seems to me we have better evidence than even direct 
observation would be, because it is more universal—namely, the 
evidence of necessity. It must be so.”—(Contributions. ft. jog.) 
The assertion that Natural Selection is a necessary 
truth is so far true that, if we grant its premises, the result 
which it predicts must necessarily take place. But the 
reliability of the result depends upon the correctness of 
the statement of the case. If you assume that the 
fecundity of the organic world, and the limited area for 
the accommodation of living forms, must lead to a struggle 
for existence; that this struggle for existence must 
exercise a selective influence in all essential respects 
analogous to the selection practised by the cattle- 
breeder and the pigeon-fancier—if you assume that this