Graham Greene wrote a book which was made into a 1949 movie starring Joseph Cotten and Orson Wells. To give away the plot would be crass, but the question the story asks is: Who is the “third man”?
This question also stalks the findings on how evolution actually occurs: by a process called natural selection. And though I’ve studied and taught evolution for over three decades, I myself only recently became aware of the “Third Man”, Patrick Matthew. The other two, of course, are Charles Darwin and Alfred Russel Wallace. Patrick Matthew discovered and wrote of the process – natural selection – by which evolution occurs in his book On Naval Timber and Arboriculture; With Critical Notes on Authors who have Recently Treated the Subject of Planting in 1831. For context, this was also the year when Charles Darwin set sail on the Beagle, which took him to the Galapagos where he conceived the idea of individuals best adapted to the environment surviving to pass on their genes in an iterative process, leading to better and better adaptation in future generations.
Patrick Matthew was a Scottish landowner who opined that the growing of trees suitable for use in shipbuilding which helped “Britannia rule the waves” as predicated on the quality of the trees themselves. Thus, he set himself to studying agriculture and forestry. From his practical experience, he came up with the idea of the “circumstance-adaptive” law by which nature selected the best trees to perpetuate, but man with his incomplete knowledge perpetuated poor specimens.
Matthew wrote: “There is a law universal in nature, tending to render every reproductive being the best possibly suited to its condition that its kind, or that organized matter, is susceptible of, which appears intended to model the physical and mental or instinctive powers, to their highest perfection, and to continue them so. This law sustains the lion in his strength, the hare in her swiftness, and the fox in his wiles. As Nature, in all her modifications of life, has a power of increase far beyond what is needed to supply the place of what falls by Time’s decay, those individuals who possess not the requisite strength, swiftness, hardihood, or cunning, fall prematurely without reproducing – either a prey to their natural devourers, or sinking under disease, generally induced by want of nourishment, their place being occupied by the more perfect of their own kind, who are pressing on the means of subsistence.”[1]
Patrick Matthew’s work was recently (2015) reintroduced to the world by Michael Weale of King’s College, London. In his paper to the Linnaean Society, famously the place where Darwin and Wallace jointly presented their work in 1858, Weale writes: “The great conceptual leap was to see natural selection as a mechanism for the origin of species, or ‘macroevolution’ (as defined here to include speciation). Famously, Charles Darwin and Alfred Russel Wallace saw this, revealing it in their joint paper to the Linnean Society.[2] However, the first person known to have made this leap, 27 years earlier, is also the least famous. Patrick Matthew proves that the idea was accessible to someone from outside the usual naturalist circles. At the same time, he is proof of how inaccessible that idea was, for apparently no fourth person thought of it in that 27-year period, or appreciated his version of it, and even Matthew appeared not to understand all of its implications.”
There are four key points that Matthew pointed out that, later, Darwin and Wallace also agreed on:
- Struggle for existence. There is overproduction and many individuals die, while some go on to reproduce.
- Variation is the basis of selection. There are a huge variety of individuals with different abilities. This variability is the factor that natural selection acts on; some survive environmental pressures and others do not.
- Heritability of traits. Traits that are successful for survival are passed on to the offspring in their genes, making them iteratively better adapted to the environment.
- Macroevolution by natural selection. New species are descended from species that went before by modification of certain traits that make them more adapted to the environment. This is descent with modification.
Darwin and Wallace agreed on some other factors: the existence of a single origin for all life and the absence of spontaneous generation of life, which Matthew disagreed with; Wallace and Matthew shared an opinion on progressive evolution and designed universal laws which Darwin did not credit; and Darwin and Matthew agreed on inheritance of acquired characters and absence of an intelligent intervention in evolution, both of which Wallace did not agree with. Thus they are overlapping similarities in their thinking, but their thinking is not alike.
In 1860, after Darwin and Wallace were feted for their idea of evolution by natural selection, Matthew wrote to point out the similarities in ideas to his own 1831 work. Both Darwin and Wallace accepted that Matthew had made important contributions, although neither acknowledged being aware of, or affected by, these ideas. Darwin wrote: “”I freely acknowledge that Mr. Matthew has anticipated by many years the explanation which I have offered of the origin of species,” while Wallace wrote publicly in 1879 of “how fully and clearly Mr. Matthew apprehended the theory of natural selection, as well as the existence of more obscure laws of evolution, many years in advance of Mr. Darwin and myself,” and that Matthew was “one of the most original thinkers of the first half of the 19th century.”
Had Matthew’s work been better known, perhaps Darwin’s and Wallace’s exceptional contributions would have helped to build its reputation further. As it is, Darwin’s body of work was already so extraordinary, his acceptance of Matthew’s contributions provide support for an obscure landowner’s obscure studies. Perhaps we can all take a leaf out of Matthew’s book and observe and think about something in our familiar backyards, and derive a meaningful and thoughtful contribution, publicized or no.
[1]. Weale, M.E. (2015) Patrick Matthew’s law of natural selection. Biological Journal of the Linnean Society, Volume 115, Issue 4, , Pages 785–791, https://doi.org/10.1111/bij.12524
[2]. Darwin CR, Wallace AR. (1958) On the tendency of species to form varieties; and on the perpetuation of varieties and species by natural means of selection. Journal of the Proceedings of the Linnaean Society: Zoology. 3, 45-62
