Thursday, 1 March 2018

Comparing the respective transmutation mechanisms of Patrick Matthew, Charles Darwin and Alfred Wallace

The original article has been published at the Biological Journal of the Linnean Society 123(4): 864-78 (2018): [This link brings you to a guest entrance, that is, through the paywall to the full article.] A pre-print version is available here.

The elaborate acknowledgements
I'd like to take the chance to be more elaborate, here, than in the published paper. After a rash rejection by the Journal of the History of Biology, Mike Weale has, for some time, engaged in a ping-pong game of him commenting on the manuscript and me sending him corrected versions back. I also invited Julian Derry to become co-author around that time, but the plan never panned out for various reasons. Nevertheless, Julian's input via e-mail discussions was as helpful as that of Mike Weale.

Despite these important roles of Julian Derry and Mike Weale, the three of us reconstruct Matthew's views differently. (Reconstruction is inevitable for a record as incomplete as Matthew's. It's as if we have a most complete fossil record for Darwin, most of it for Wallace, but only a jaw, and a leg, and a tail for Matthew.) Let me sketch the differences between Weale, Derry and me as aptly as possible. Weale believes that Matthew proposed an early version of species transmutation through natural selection. Derry and I disagree.
    I think Matthew's scheme proposed species transmutation with natural selection also being in it, but not being the central force that does the transforming. On the contrary, Matthew's scheme suggests that natural selection works species fixing except after catastrophes have ripped remnant species apart and thrown them into habitats which they did not naturally occupy before the catastrophe. That is, natural selection only ever works (anagenetically) to adapt a lineage to its environment and the catastrophe does the lineage splitting. Natural selection does play some role, here, during the process of species transformation and lineage splitting, but not the central role that it does play in Darwin's mature theory. In the latter, natural selection and the principle of divergence were sufficient to effect divergence and speciation in symparty.
    Finally, Derry reads Matthew as having >natural selection and species transmutation, separately, but both do not work together in the transformation. Hence, out three different readings of Matthew (1831, On Naval Timber and Arboriculture) can be aptly summarized as species transmutation through natural selection as the central factor (Weale), species transmutation with natural selection playing a lateral role (me), and species transmutation without natural selection playing any role in it (Derry) but getting a species fixing role after transmutation.

The information about the enigma of Matthew's university education reached me via Mike Weale, but he insisted that his source, Anne Carroll then of Perth Library, be acknowledged for it rather than him.* David Lloyd was a peer reviewer who waved anonymity. He and two anonymous reviewers helped to improve the paper a lot, especially on Alfred Wallace. A rant about the second reviewer (there were four in total) could follow, but everybody knows what "reviewer no. 2" means. I must praise the gumption of the editor in chief, John Allen, however. When I challenged the one glib and uncomprehending sentence that constituted the 2nd review, he bethought himself and revised his decision from rejection to re-write. Finally, thanks to Alexandra Elbakyan for literature.

* [A great amount of new information concerning the enigma of Matthew's education has been collected by a team (Anne Carroll, Julian Derry, Mike Weale, and I) and I have collated it in a blog piece lest I forget the links and details. In my opinion, this is a fine example of a person (Patrick Matthew from Newbigging—not Gourdiehill) that has for a long time rotten in the archives as a person of no historical significance whatsoever, brought back to life and linked to a question of historical significance by four accomplished sleuths.]

A comparison of the evolutionary mechanisms of Patrick Matthew, Charles Darwin, and Alfred Wallace highlights their differences. In Matthew’s scheme, catastrophes initiate periods of radiation and speciation until a fully stocked environment gets into stasis. Catastrophes first needed to exterminate competing species before the survivors could radiate into free niches and diversify into new species. In Darwin's early theory conditions of life, such as prevail under domestication, first need to increase the variability of a species, before natural selection can transform it. In Darwin's mature theory competition replaced conditions as the main drive behind evolutionary change and sympatric speciation becomes possible. Wallace’s theory differed from both Matthew’s and Darwin’s. Interspecific competition was neither a brake halting transmutation (as in Matthew’s) nor intraspecific competition a sufficient drive for it. While each theory integrated natural selection with variability, competition and changed conditions in distinct ways, each allowed for species transmutation somehow. The result was similar (transmutation), but the mechanisms yielding that result (the integration of natural selection with variability, competition, change in conditions) differed significantly.