Edward Blyth - On Natural Selection

On Natural Selection

Edward Blyth wrote three articles on variation, discussing the effects of artificial selection and describing the process in nature (later called natural selection) as restoring organisms in the wild to their archetype (rather than forming new species). However, he never actually used the term "natural selection". These articles were published in The Magazine of Natural History between 1835 and 1837.

In February 1855 Charles Darwin, seeking information on variations in domesticated animals of various countries, wrote to Blyth who was "much gratified to learn that a subject in which I have always felt the deepest interest has been undertaken by one so competent to treat of it in all its bearings" and they corresponded on the subject. Blyth was among the first to recognise the significance of Wallace's paper "On the Law which has regulated the introduction of Species" and brought it to the notice of Darwin in a letter written in Calcutta on December 8, 1855:

"What think you of Wallace's paper in the Ann. M. N. H. ? Good! Upon the whole! ... Wallace has, I think, put the matter well; and according to his theory, the various domestic races of animals have been fairly developed into species. ... A trump of a fact for friend Wallace to have hit upon!"

There can be no doubt of Darwin's regard for Edward Blyth: in the first chapter of On the Origin of Species he wrote "Mr. Blyth, whose opinion, from his large and varied stores of knowledge, I should value more than that of almost any one, ..."

In a 1959 paper, Loren Eiseley claimed that "the leading tenets of Darwin's work – the struggle for existence, variation, natural selection and sexual selection – are all fully expressed in Blyth's paper of 1835". He also cited a number of rare words, similarities of phrasing, and the use of similar examples, which he regarded as evidence of Darwin's debt to Blyth. However, the subsequent discovery of Darwin's notebooks has "permitted the refutation of Eiseley's claims". Eiseley argued that Blyth's influence on Darwin "begins to be discernible in the Darwin Note-book of 1836 with the curious word 'inosculate'. It is a word which has never had a wide circulation, and which is not to be found in Darwin's vocabulary before this time." This was incorrect: an 1832 letter written by Darwin commented that William Sharp Macleay "never imagined such an inosculating creature". The letter preceded Blyth's publication, and indicates that both Darwin and Blyth had independently taken the term from Macleay whose Quinarian system of classification had been popular for a time after its first publication in 1819–1820. In a mystical scheme this grouped separately created genera in "osculating" (kissing) circles.

Both Mayr and Darlington interpret Blyth's view of natural selection as maintaining the type:

"Blyth's theory was clearly one of elimination rather than selection. His principal concern is the maintenance of the perfection of the type. Blyth's thinking is decidedly that of a natural theologian..."

"What was the work of Blyth?... Blyth attempts to show how can be used to explain, not the change of species (which he was anxious to discredit) but the stability of species in which he ardently believed."

In this negative formulation, natural selection only preserves a constant and unchangeable type or essence of created form, by eliminating extreme variations or unfit individuals that deviate too far from this essence. The formulation goes back to the ancient Greek philosopher Empedocles, and the theologian William Paley set out a variation on this argument in 1802, to refute (in later pages) a claim that there had been a wide range of initial creations, with less viable forms eliminated by nature to leave the modern range of species:

"The hypothesis teaches, that every possible variety of being hath, at one time or other, found its way into existence (by what cause or in what manner is not said), and that those which were badly formed, perished; but how or why those which survived should be cast, as we see that plants and animals are cast, into regular classes, the hypothesis does not explain; or rather the hypothesis is inconsistent with this phænomenon."

The way Blyth himself argued about the modification of species can be illustrated by an extract concerning the adaptations of carnivorous mammals:

"However reciprocal...may appear the relations of the preyer and the prey, a little reflection on the observed facts suffices to intimate that the relative adaptations of the former only are special, those of latter being comparatively vague and general; indicating that there having been a superabundance which might serve as nutriment, in the first instance, and which, in many cases, was unattainable by ordinary means, particular species have therefore been so organized (that is to say, modified upon some more or less general type or plan of structure,) to avail themselves of the supply."

Stephen Jay Gould writes that Eiseley erred in failing to realize that natural selection was a common idea among biologists of the time, as part of the argument for created permanency of species. It was seen as eliminating the unfit, while some other cause created well fitted species. Darwin introduced the idea that natural selection was creative in giving direction to a process of evolutionary change in which small hereditary changes accumulate. John Wilkins indicates that Blyth considered that species had "invariable distinctions" establishing their integrity, and so was opposed to transmutation of species as if it occurred, "we should seek in vain for those constant and invariable distinctions which are found to obtain". Darwin held the opposite view, and did not read Blyth until after formulating his own theory. In contrast to Eiseley's claim that Blyth felt that Darwin had plagiarised the idea, Blyth remained a valued correspondent of Darwin's after the idea was published, and remained a strong friend of Darwin.