The Foundations of the Origin of Species.
by Charles Darwin.
INTRODUCTION
We know from the contents of Charles Darwin"s Note Book of 1837 that he was at that time a convinced 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?
{1} See the extracts in _Life and Letters of Charles Darwin_, ii.
p. 5.
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 extermination 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. They die, without they change, like golden pippins; it is a _generation of species_ like generation _of individuals_."
"If _species_ generate other _species_ their race is not utterly cut off."
{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 _Darwin 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.
These quotations show that he was struggling to see in the origin of species a process just as scientifically comprehensible as the birth of individuals. They show, I think, that he recognised the two things not merely as similar but as identical.
It is impossible to know how soon the ferment of uniformitarianism began to work, but it is fair to suspect that in 1832 he had already begun to see that mutability was the logical conclusion of Lyell"s doctrine, though this was not acknowledged by Lyell himself.
There were however other factors of change. In his Autobiography{5} he wrote:--"During the voyage of the _Beagle_ I had been deeply impressed by discovering in the Pampean formation great fossil animals covered with armour like that on the existing armadillos; secondly, by the manner in which closely allied animals replace one another in proceeding southward over the Continent; and thirdly, by the South American character of most of the productions of the Galapagos archipelago, and more especially by the manner in which they differ slightly on each island of the group; none of the islands appearing to be very ancient in a geological sense. It was evident that such facts as these, as well as many others, could only be explained on the supposition that species gradually become modified; and the subject haunted me."
{5} _Life and Letters_, i. p. 82.
Again we have to ask: how soon did any of these influences produce an effect on Darwin"s mind? Different answers have been attempted.
Huxley{6} held that these facts could not have produced their essential effect until the voyage had come to an end, and the "relations of the existing with the extinct species and of the species of the different geographical areas with one another were determined with some exactness." He does not therefore allow that any appreciable advance towards evolution was made during the actual voyage of the _Beagle_.
{6} _Obituary Notice_, _loc. cit._
Professor Judd{7} takes a very different view. He holds that November 1832 may be given with some confidence as the "date at which Darwin commenced that long series of observations and reasonings which eventually culminated in the preparation of the _Origin of Species_."
{7} _Darwin and Modern Science._
Though I think these words suggest a more direct and continuous march than really existed between fossil-collecting in 1832 and writing the _Origin of Species_ in 1859, yet I hold that it was during the voyage that Darwin"s mind began to be turned in the direction of Evolution, and I am therefore in essential agreement with Prof. Judd, although I lay more stress than he does on the latter part of the voyage.
Let us for a moment confine our attention to the pa.s.sage, above quoted, from the Autobiography and to what is said in the Introduction to the _Origin_, Ed. i., viz. "When on board H.M.S. "Beagle," as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent." These words, occurring where they do, can only mean one thing,--namely that the facts suggested an evolutionary interpretation. And this being so it must be true that his thoughts _began to flow in the direction of Descent_ at this early date.
I am inclined to think that the "new light which was rising in his mind{8}" had not yet attained any effective degree of steadiness or brightness. I think so because in his Pocket Book under the date 1837 he wrote, "In July opened first note-book on "trans.m.u.tation of species."
Had been greatly struck _from about month of previous March_{9} on character of South American fossils, and species on Galapagos Archipelago. These facts origin (_especially latter_), of all my views."
But he did not visit the Galapagos till 1835 and I therefore find it hard to believe that his evolutionary views attained any strength or permanence until at any rate quite late in the voyage. The Galapagos facts are strongly against Huxley"s view, for Darwin"s attention was "thoroughly aroused{10}" by comparing the birds shot by himself and by others on board. The case must have struck him at once,--without waiting for accurate determinations,--as a microcosm of evolution.
{8} Huxley, _Obituary_, p. xi.
{9} In this citation the italics are mine.
{10} _Journal of Researches_, Ed. 1860, p. 394.
It is also to be noted, in regard to the remains of extinct animals, that, in the above quotation from his Pocket Book, he speaks of March 1837 as the time at which he began to be "greatly struck on character of South American fossils," which suggests at least that the impression made in 1832 required reinforcement before a really powerful effect was produced.
We may therefore conclude, I think, that the evolutionary current in my father"s thoughts had continued to increase in force from 1832 onwards, being especially reinforced at the Galapagos in 1835 and again in 1837 when he was overhauling the results, mental and material, of his travels. And that when the above record in the Pocket Book was made he unconsciously minimised the earlier beginnings of his theorisings, and laid more stress on the recent thoughts which were naturally more vivid to him. In his letter{11} to Otto Zacharias (1877) he wrote, "On my return home in the autumn of 1836, I immediately began to prepare my Journal for publication, and then saw how many facts indicated the common descent of species." This again is evidence in favour of the view that the later growths of his theory were the essentially important parts of its development.
{11} F. Darwin"s _Life of Charles Darwin_ (in one volume), 1892, p.
166.
In the same letter to Zacharias he says, "When I was on board the _Beagle_ I believed in the permanence of species, but as far as I can remember vague doubts occasionally flitted across my mind." Unless Prof.
Judd and I are altogether wrong in believing that late or early in the voyage (it matters little which) a definite approach was made to the evolutionary standpoint, we must suppose that in 40 years such advance had shrunk in his recollection to the dimensions of "vague doubts." The letter to Zacharias shows I think some forgetting of the past where the author says, "But I did not become convinced that species were mutable until, I think, two or three years had elapsed." It is impossible to reconcile this with the contents of the evolutionary Note Book of 1837.
I have no doubt that in his retrospect he felt that he had not been "convinced that species were mutable" until he had gained a clear conception of the mechanism of natural selection, _i.e._ in 1838-9.
But even on this last date there is some room, not for doubt, but for surprise. The pa.s.sage in the Autobiography{12} is quite clear, namely that in October 1838 he read Malthus"s _Essay on the principle of Population_ and "being well prepared to appreciate the struggle for existence ..., it at once struck me that under these circ.u.mstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here then I had at last got a theory by which to work."
{12} _Life and Letters_, i. p. 83.
It is surprising that Malthus should have been needed to give him the clue, when in the Note Book of 1837 there should occur--however obscurely expressed--the following forecast{13} of the importance of the survival of the fittest. "With respect to extinction, we can easily see that a variety of the ostrich (Petise{14}), may not be well adapted, and thus perish out; or on the other hand, like Orpheus{15}, being favourable, many might be produced. This requires the principle that the permanent variations produced by confined breeding and changing circ.u.mstances are continued and produce according to the adaptation of such circ.u.mstances, and therefore that death of species is a consequence (contrary to what would appear in America) of non-adaptation of circ.u.mstances."{13} _Life and Letters_, ii. p. 8.
{14} Avestruz Petise, _i.e. Rhea Darwini_.
{15} A bird.
I can hardly doubt, that with his knowledge of the interdependence of organisms and the tyranny of conditions, his experience would have crystallized out into "a theory by which to work" even without the aid of Malthus.
In my father"s Autobiography{16} he writes, "In June 1842 I first allowed myself the satisfaction of writing a very brief abstract of my theory in pencil in 35 pages; and this was enlarged during the summer of 1844 into one of 230 pages{17}, which I had fairly copied out and still possess." These two Essays, of 1842 and 1844, are now printed under the t.i.tle _The Foundations of the Origin of Species_.
{16} _Life and Letters_, i. p. 84.
{17} It contains as a fact 231 pp. It is a strongly bound folio, interleaved with blank pages, as though for notes and additions.
His own MS. from which it was copied contains 189 pp.
It will be noted that in the above pa.s.sage he does not mention the MS.
of 1842 as being in existence, and when I was at work on _Life and Letters_ I had not seen it. It only came to light after my mother"s death in 1896 when the house at Down was vacated. The MS. was hidden in a cupboard under the stairs which was not used for papers of any value, but rather as an overflow for matter which he did not wish to destroy.
The statement in the Autobiography that the MS. was written in 1842 agrees with an entry in my fathers Diary:--
"1842. May 18th went to Maer. June 15th to Shrewsbury, and on 18th to Capel Curig.... During my stay at Maer and Shrewsbury (five years after commencement) wrote pencil sketch of my species theory." Again in a letter to Lyell (June 18, 1858) he speaks of his "MS. sketch written out in 1842{18}." In the _Origin of Species_, Ed. i. p. 1, he speaks of beginning his speculations in 1837 and of allowing himself to draw up some "short notes" after "five years" work," _i.e._ in 1842. So far there seems no doubt as to 1842 being the date of the first sketch; but there is evidence in favour of an earlier date{19}. Thus across the Table of Contents of the bound copy of the 1844 MS. is written in my father"s hand "This was sketched in 1839." Again in a letter to Mr Wallace{20} (Jan. 25, 1859) he speaks of his own contributions to the Linnean paper{21} of July 1, 1858, as "written in 1839, now just twenty years ago." This statement as it stands is undoubtedly incorrect, since the extracts are from the MS. of 1844, about the date of which no doubt exists; but even if it could be supposed to refer to the 1842 Essay, it must, I think, be rejected. I can only account for his mistake by the supposition that my father had in mind the date (1839) at which the framework of his theory was laid down. It is worth noting that in his Autobiography (p. 88) he speaks of the time "about 1839, when the theory was clearly conceived." However this may be there can be no doubt that 1842 is the correct date. Since the publication of _Life and Letters_ I have gained fresh evidence on this head. A small packet containing 13 pp. of MS. came to light in 1896. On the outside is written "First Pencil Sketch of Species Theory. Written at Maer and Shrewsbury during May and June 1842." It is not however written in pencil, and it consists of a single chapter on _The Principles of Variation in Domestic Organisms_. A single unnumbered page is written in pencil, and is headed "Maer, May 1842, useless"; it also bears the words "This page was thought of as introduction." It consists of the briefest sketch of the geological evidence for evolution, together with words intended as headings for discussion,--such as "Affinity,--unity of type,--foetal state,--abortive organs."
{18} _Life and Letters_, ii. p. 116.
{19} _Life and Letters_, ii. p. 10.