To W. R. Greg 31 December 1878
Down | Beckenham
Dec 31, 1878
My dear Mr Greg,
I have read the chapter on design & it seems to me very cleverly done. If your son has not read a book by “Physicus” just published by Trübner, I think it would be worth his reading as bearing on the argument from general laws; not that Physicus appears to me to have made out his case, tho’ the subject is beyond my tether. To come to my own subjects, I do not think that any of your sons objections are new, tho’ some of them are put in a new way. It would take a volume to discuss all, but I will make a few miscellaneous remarks. If your son cares to see what I think about variations having been designed, he will find this subject briefly discussed in the 3 last pages of Vol II of my ‘Variation under Domestn’. Your son would hesitate in saying that no close series of forms have been found fossil if he were to read Saporta on the Tertiary plants of S. France,—Geinitz & Oppell on the Jurassic ammonites—or Neumayr on the Miocene fresh water shells of East Europe. Your son says that no links have been found between such forms as the ass & zebra but he forgets that it is doubtful whether any palæontologist could distinguish their bones; & bones alone afford evidence when we come to fossil mammals. With respect to new variations being obliterated by crossing, I have insisted on the improbability of such well marked variations as that of the Ancon sheep being preserved under nature. I cannot doubt that the process of selection under nature is the same as that called by me “unconscious selection”, when the more or less best fitted are preserved, & the more or less ill fitted are destroyed. If your son thinks it worth while he can see what I mean by unconscious selection in Ch XX of Varn under Domn. Your son does not notice the effects of separation, as on islands, in preventing crossing. By the way he says I rest exclusively on natural selection; whereas no one else as far as I know has made so many observations on the effects of use & disuse. Nor do I deny the direct effect of external conditions, tho’ I probably underrated their power in the earlier editions of the Origin. We know far too little about the laws of inheritance to argue about them: what is certain is that some new variations are strongly inherited from the first, whilst some seem never or very rarely to be transmitted; nor until trial is made can we predict what will be the result. Your son believes that our domesticated animals were developed for man’s use; but let us suppose that they were all destroyed, does your son believe that man would not succeed in domesticating other quadrupeds, for instance some of the larger antilopes; & in this case ought not your son to maintain that such animals had been specially designed for man. Owen goes further than your son for in referring to race horses he says that he believes the diastema or open space between their teeth to have been specially designed for the bit; & as a friend of mine remarked no doubt the little jockeys were specially designed to ride them.
Your son seems to believe that ice has been made lighter than water, as otherwise it would have sunk & whole pools or seas have been frozen into a solid mass. But melted bismuth when cooling & solidifying expands largely (by of its bulk) & of course floats, is this a special adaptation? It is much more wonderful & apparently unique case that solid bismuth if subjected to an enormous pressure becomes of less specific gravity; if this lightness had been of any use to man, assuredly it would have been called a special adaptation. But I shall weary you, & I remain, my dear Mr Greg
Yours sincerely | Charles Darwin
Discusses a chapter on design, written by WRG’s son [Percy Greg, The devil’s advocate (1878)]. Comments on the younger Greg’s criticisms of natural selection and evolution.
Please cite as
Darwin Correspondence Project, “Letter no. 11812,” accessed on 28 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-11812