INTRODUCTION 



WE know from the contents of Charles Darwin's 

 Note Book of 1837 that he was at that time a con- 

 vinced Evolutionist 1 . Nor can there be any doubt 

 that, when he started on board the Beagle, such 

 opinions as he had were on the side of immutability. 

 When therefore did the current of his thoughts 

 begin to set in the direction of Evolution ? 



We have first to consider the factors that made 

 for such a change. On his departure in 1831, 

 Henslow gave him vol. i. of Lyell's Principles, then 

 just published, with the warning that he was not to 

 believe what he read 2 . But believe he did, and it 

 is certain (as Huxley has forcibly pointed out 3 ) that 

 the doctrine of uniformitarianism when applied to 

 Biology leads of necessity to Evolution. If the ex- 

 termination of a species is no more catastrophic 

 than the natural death of an individual, why should 

 the birth of a species be any more miraculous than 

 the birth of an individual ? It is quite clear that 

 this thought was vividly present to Darwin when he 

 was writing out his early thoughts in the 1837 

 Note Book 4 :- 



" Propagation explains why modern animals 

 same type as extinct, which is law almost proved. 



1 See the extracts in Life and Letters of Charles Darwin, ii. p. 5. 



2 The second volume, especially important in regard to Evolution, 

 reached him in the autumn of 1832, as Prof. Judd has pointed out in his 

 most interesting paper in Dancin and Modern Science. Cambridge, 1909. 



3 Obituary Notice of C. Darwin, Proc. R. Soc. vol. 44. Reprinted in 

 Huxley's Collected Essays. See also Life and Letters of C. Darwin, ii. 

 p. 179. 



4 See the extracts in the Life and Letters, ii. p. 5, 



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