57 



into new species, by the process of natural selection, which 

 process is essentially identical with that artificial selection by 

 which man has originated the races of domestic animals — the 

 struggle for existence taking the place of man, and exerting, in 

 the case of natural selection, that selective action which he 

 performs in artificial selection."^ 



The crucial point in this hypothesis is, that species may be 

 originated by natural selection. But Huxley, and Darwin 

 himself, admit that this has never been proved. Darwin, it is 

 true, draws largely upon an infinite past. He says, " Nature 

 grants vast periods of time for the work of natural selection ; " 

 and again, "The mind cannot possibly grasp the full meaning 

 of a hundred milUon of years. It cannot add up and perceive 

 the full efifects of many slight variations accumulated during 

 almost an infinite series of generations.^' Now as to this 

 "almost infinite past,'' Sir Wm. Thomson, probably the 

 most profound of our physicists, has dissipated all such 

 speculation by showing that life-forms such as Darwin postu- 

 lates could not have existed during an infinite past; "because, 

 assuming that the heat has been uniformly conducted out 

 of the earth, as it is now, it must have been so intense 

 within a comparatively limited period, as to be capable of 

 melting a mass of rock equal to the bulk of the whole 

 earth." f But, be this as it may, one thing is clear, that 

 Darwin and his fellow scientists admit their inability to prove 

 the truth of the Evolution Hypothesis. 



Another point set forth by Darwin is worthy of notice. In 

 answer to the question. How do groups of species arise ? he 

 replies, " From the struggle for life. Owing to their struggle 

 for life, any variation, however slight, aud from whatever 

 cause proceeding, if it be in any degree profitable to an 

 individual of the species, in its infinitely complex relations to 

 other organic beings and to external nature, will tend to the 

 preservation of that individual, and will generally be inherited 

 by its offspring. The offspring, also, will thus have a better 

 chance of surviving." | The essence of this most remarkable 

 hypothesis is, that all the wonderful adaptations which we find in 

 the physical structure of the various species of animals, to the 

 conditions in which they are placed, to the work they have to 

 do, to the wants they have to supply, have sprung from a long 

 aud fortuitous sequence of natural events, to which Darwin 

 gives the name Natural Selection. If this be true, then the 



* See Huxley, Lay Sermons, pp. 292, seq. 



t Frazer, Blending Lights, p. 4. J Origin of Species, p. 61. 



