ADDRESS. 13 



at least many hundred million years for the accomplishment of the stu- 

 pendous process. Of course, if the mathematicians are right, the biologists 

 cannot have what they demand. If, for the purposes of their theory, organic 

 life must have existed on the globe more than a hundred million years 

 ago, it must, under the temperature then prevailing, have existed in a state 

 of vapour. The jelly-fish would have been dissipated in steam long before 

 he had had a chance of displaying the advantageous variation which was 

 to make him the ancestor of the human race. I see, in the eloquent dis- 

 course of one of my most recent and most distinguished predecessors in this 

 chair. Sir Archibald Geikie, that the controversy is still alive. The mathe- 

 maticians sturdily adhere to their figures, and the biologists are quite sure 

 the mathematicians must have made a mistake. I will not get myself into 

 the line of fire by intervening in such a controversy. But until it is 

 adjusted the laity may be excused for returning a verdict of ' not proven ' 

 upon the wider issues the Darwinian school has raised. 



The other objection is best stated in the words of an illustrious disciple 

 pf Darwin, Avho has recently honoured this city by his presence — I refer 

 to Professor Weismann. But in referring to him, I cannot but give, in 

 passing, a feeble expression to the universal sorrow with which in this 

 place the news was received that Weismann's distinguished antagonist, 

 Professor Romanes, had been taken from us in the outset and full promise 

 of a splendid scientific career. 



The gravest objection to the doctrine of natural selection was expressed 

 by Weismann in a paper published a few months ago, not as agreeing to 

 the objection, but as resisting it ; and therefore his language may be taken 

 .as an impartial statement of the difficulty. ' We accept natural selection,' 

 he says, ' not because we are able to demonstrate the process in detail, not 

 even because we can with more or less ease imagine it, but simply because 

 we must— because it is the only possible explanation that we can conceive. 

 We must assume natural selection to be the principle of the explana- 

 tion of the metamorphoses, because all other apparent principles of 

 explanation fail us, and it is inconceivable that there could yet be another 

 capable of explaining the adaptation of organisms without assuming the 

 help of a principle of design.' 



There is the difficulty. We cannot demonstrate the process of natural 

 selection in detail ; we cannot even, with more or less ease, imagine it. It 

 is purely hypothetical. No man, so far as we know, has ever seen it at 

 work. An accidental variation may have been perpetuated by inhei'itance, 

 and in the struggle for existence the bearer of it may have replaced, bv 

 virtue of the survival of the fittest., his less improved competitors ; but as 

 far as we know no man or succession of men have ever observed the whole 

 process in any single case, and certainly no man has recorded the obser- 

 vation. Variation by artificial selection, of course, we know very well ; 

 but the intei'vention of the cattle breeder and the pigeon fancier is the 

 essence of artificial selection. It is effected by their action in crossing, 

 by their skill in bringing the right mates together to produce the progeni- 



