14 Darwin's Predecessors 



Selection in his exposition of the eliminative processes which go on 

 in mankind, the suggestive value of his essay is undeniable, as is 

 strikingly borne out by the fact that it gave to Alfred Russel Wallace 

 also " the long-sought clue to the effective agent in the evolution of 

 organic species 1 ." One day in Ternate when he was resting between 

 fits of fever, something brought to his recollection the work of Malthus 

 which he had read twelve years before. "I thought of his clear 

 exposition of 'the positive checks to increase' — disease, accidents, 

 war, and famine — which keep down the population of savage races to 

 so much lower an average than that of more civilized peoples. It 

 then occurred to me that these causes or their equivalents are 

 continually acting in the case of animals also ; and as animals usually 

 breed much more rapidly than does mankind, the destruction every 

 year from these causes must be enormous in order to keep down the 

 numbers of each species, since they evidently do not increase regularly 

 from year to year, as otherwise the world would long ago have been 

 densely crowded with those that breed most quickly. Vaguely 

 thinking over the enormous and constant destruction which this 

 implied, it occurred to me to ask the question, Why do some die 

 and some live ? And the answer was clearly, that on the whole the 

 best fitted live. From the effects of disease the most healthy escaped ; 

 from enemies the strongest, the swiftest, or the most cunning ; from 

 famine the best hunters or those with the best digestion ; and so on. 

 Then it suddenly flashed upon me that this self-acting process would 

 necessarily improve the race, because in every generation the inferior 

 would inevitably be killed off and the superior would remain — that 

 is, the fittest would survive 2 ." We need not apologise for this long 

 quotation, it is a tribute to Darwin's magnanimous colleague, the 

 Nestor of the evolutionist camp, — and it probably indicates the line 

 of thought which Darwin himself followed. It is interesting also to 

 recall the fact that in 1852, when Herbert Spencer wrote his famous 

 Leader article on "The Development Hypothesis" in which he 

 argued powerfully for the thesis that the whole animate world is 

 the result of an age-long process of natural transformation, he wrote 

 for The Westminster Review another important essay, "A Theory 

 of Population deduced from the General Law of Animal Fertility," 

 towards the close of which he came within an ace of recognising that 

 the struggle for existence was a factor in organic evolution. At 

 a time when pressure of population was practically interesting men's 

 minds, Darwin, Wallace, and Spencer were being independently led 

 from a social problem to a biological theory. There could be no 

 better illustration, as Prof. Patrick Geddes has pointed out, of the 

 Comtian thesis that science is a "social phenomenon." 



1 A. E. Wallace, My Life, A Record of Events and Opinions, London, 1905, Vol. i. p. 232. 



2 Ibid. Vol. i. p. 361. 



