You’ll be hearing that a lot on science blogs over the next year-and-a-half in the run-up to November 24, 2009, the 150th anniversary of the publication of Charles Darwin’s “Origin of Species”. But we should start with another 150th anniversary that is marked today, July 1, 2008…
One hundred fifty years ago, this date fell on a Thursday. On that Thursday, the meeting of the Linnean Society in London had a reading of an essay by Alfred Russel Wallace and a manuscript chapter extract and a letter from Charles R. Darwin on the topic of tranformism, or the evolution of new species from existing species. This collage of material was presented under a single title, On the tendency of species to form varieties; and on the perpetuation of varieties and species by natural means of selection.
The reading itself produced hardly a ripple in the currents of scientific discourse; the Linnean Society president Thomas Bell noted in his journal that nothing of importance took place in that year. The real story lay in how it came to be that there was a joint presentation of material from Wallace and Darwin, rather than Wallace alone, and in the course of history that followed on.
(Original posting at the Austringer.)
Wallace was a naturalist in the field, his field being first the Amazon basin and later the Malay Archipelago. One of the hazards of being a European naturalist out in those regions was disease, and Wallace suffered an attack of malaria. While feverish, Wallace worked out the basics of how natural causes could explain the adaptations that mark different species of organisms. Once recovered, he wrote out an essay on the subject, and sent that on to Charles Darwin, with whom he had previously corresponded on the topic of transformism.
The essay, titled “On the Tendency of Varieties to depart indefinitely from the Original Type”, caught Darwin rather by surprise. While Darwin appreciated Wallace’s previous paper promulgating the “Sarawak Law” that all species are found in geographic proximity to allied species, Darwin had apparently classed Wallace’s views on tranformism as corresponding to progressive creationism. In the essay Darwin read in spring of 1858, though, Wallace clearly laid out the very mechanism of natural selection that Darwin had cogitated over for about twenty years. Clearly, Wallace’s essay deserved publication, but what of Darwin’s own, unpublished, work on the topic? Darwin took the matter to his friends, Charles Lyell and Joseph Hooker. They have a preface to the piece read to the Linnean Society 150 years ago that explains their solution to the problem.
MY DEAR SIR,—The accompanying papers, which we have the honour of communicating to the Linnean Society, and which all relate to the same subject, viz. the Laws which affect the Production of Varieties, Races, and Species, contain the results of the investigations of two indefatigable naturalists, Mr. Charles Darwin and Mr. Alfred Wallace.
These gentlemen having, independently and unknown to one another, conceived the same very ingenious theory to account for the appearance and perpetuation of varieties and of specific forms on our planet, may both fairly claim the merit of being original thinkers in this important line of inquiry; but neither of them having published his views, though Mr. Darwin has for many years past been repeatedly urged by us to do so, and both authors having now unreservedly placed their papers in our hands, we think it would best promote the interests of science that a selection from them should be laid before the Linnean Society.
Taken in the order of their dates, they consist of:—
Extracts from a MS. work on Species*, by Mr. Darwin, which was sketched in 1839, and copied in 1844,2 when the copy was read by Dr. Hooker,3 and its contents afterwards communicated to Sir Charles Lyell. The first Part is devoted to “The Variation of Organic Beings under Domestication and in their Natural State;” and the second chapter of that Part, from which we propose to read to the Society the extracts referred to, is headed, “On the Variation of Organic Beings in a state of Nature; on the Natural Means of Selection; on the Comparison of Domestic Races and true Species.”
An abstract of a private letter addressed to Professor Asa Gray, of Boston, U.S., in October4 1857, by Mr. Darwin, in which he repeats his views, and which shows that these remained unaltered from 1839 to 1857.1
An Essay by Mr. Wallace, entitled “On the Tendency of Varieties to depart indefinitely from the Original Type.”2 This was written at Ternate in February 1858, for the perusal of his friend and correspondent Mr. Darwin, and sent to him with the expressed wish that it should be forwarded to Sir Charles Lyell, if Mr. Darwin thought it sufficiently novel and interesting. So highly did Mr. Darwin appreciate the value of the views therein set forth, that he proposed, in a letter to Sir Charles Lyell, to obtain Mr. Wallace’s consent to allow the Essay to be published as soon as possible. Of this step we highly approved, provided Mr. Darwin did not withhold from the public, as he was strongly inclined to do (in favour of Mr. Wallace), the memoir which he had himself written on the same subject, and which, as before stated, one of us had perused in 1844, and the contents of which we had both of us been privy to for many years. On representing this to Mr. Darwin, he gave us permission to make what use we thought proper of his memoir, &c.; and in adopting our present course, of presenting it to the Linnean Society, we have explained to him that we are not solely considering the relative claims to priority of himself and his friend, but the interests of science generally; for we feel it to be desirable that views founded on a wide deduction from facts, and matured by years of reflection, should constitute at once a goal from which others may start, and that, while the scientific world is waiting for the appearance of Mr. Darwin’s complete work, some of the leading results of his labours, as well as those of his able correspondent, should together be laid before the public.
We have the honour to be yours very obediently,
JOS. D. HOOKER.
As solutions to wrangles over scientific priority go, this one is near the lead for deference being paid all around. Wallace and Darwin became, via this joint presentation, co-discoverers of natural selection and its proposed role in the production of new species from existing ones. The reading also forced Darwin’s hand, and the following months saw him discard his long-term project of writing a large monograph on natural selection, and instead hurry to produce an “abstract” of his work. That “abstract” is what we now know as the book, “Origin of Species”, published in November, 1859.
The Lyell-Hooker solution of producing a joint presentation to the Linnean Society has been endlessly argued over. The primary question posed would be, was the solution unfair to Wallace, whose essay lays out the logic of natural selection in graceful and economical prose, preferred by some to Darwin’s own explication? There’s a book length treatment by Brackmann of the argument that Wallace was thoroughly swindled by Darwin and Darwin’s colleagues, set to play a subordinate role to the elder naturalist. Brackmann, though, appears to have been letting a general animus for Darwin determine his approach to the material. The record of continued cordial correspondence between Darwin and Wallace, though strained at times by their varying views of selection with respect to human mental capacity, seems to run counter to various conspiratorial readings of the situation.
I’ll close this post with the final paragraph of Wallace’s Ternate essay, the last part of the presentation given to the Linnean Society 150 years ago today.
We believe we have now shown that there is a tendency in nature to the continued progression of certain classes of varieties further and further from the original type—a progression to which there appears no reason to assign any definite limits—and that the same principle which produces this result in a state of nature will also explain why domestic varieties have a tendency to revert to the original type. This progression, by minute steps, in various directions, but always checked and balanced by the necessary conditions, subject to which alone existence can be preserved, may, it is believed, be followed out so as to agree with all the phenomena presented by organized beings, their extinction and succession in past ages, and all the extraordinary modifications of form, instinct, and habits which they exhibit.
Check out material on this anniversary at the Beagle Project, too.