Alfred Russel Wallace on Evolution: A Change of
As a result--and despite good work by such investigators as Barbara Beddall, Lewis McKinney, John Langdon Brooks and Malcolm Kottler--there is still a lot about Wallace that is not generally known. Indeed, much of what is known about him is often overlooked or inadvertently distorted in treatments of his work. A recent ethnological study, for example, refers to him--twice--as 'Sir' Alfred Russel Wallace, a mistake that is best contextualized by noting that as late as 1908 Wallace published a public letter of denial in a deliberate effort to dispel a rumor that he was about to be knighted. The same work states incorrectly that his field studies in Indonesia were subsidized by the British and Dutch colonial regimes. In another recent paper the author states that there is no "testimony" by Wallace himself as to whether his debated 'change of mind' regarding the application of natural selection to humankind was due to his adoption of spiritualist beliefs--despite the fact that such commentary does exist, and in a fairly conspicuous place: the Preface to his book On Miracles and Modern Spiritualism. This writer also states that "there is no evidence" that Wallace was "in any way" influenced by the writings of William Whewell--but Wallace himself discusses Whewell on multiple occasions and the serial literature includes several articles on this very subject.
The situation is even worse in the realm of more popular treatments. Take, for example, materials now available on the World Wide Web. I have recently performed a survey of such offerings; what I found was rather troubling. On one site he is referred to as an American; on another, as a "grad student." From the text of a publicly-presented lecture available at another site we can read: "...like Darwin, he had written a book on the origin of species, citing exactly the same kinds of evidence and reaching precisely the same conclusion. ...Darwin now...said Wallace should be allowed to publish first. Wallace insisted on Darwin's right to be first. So they presented a paper together to the Linnean Society..." Practically all of the assertions made here are, of course, simply untrue: Wallace had not written a book on the origin of species, had not cited the same evidence, hadn't insisted that Darwin be allowed to publish first--nor did they even present a paper together. Another source suggests: "Wallace had requested time to speak at an upcoming conference to officially put forth his theory. Some of Charles Darwin's friends...heard about this and decided that the credit should go to Darwin, not Wallace. They did this by asking the meeting organizers for a few minutes just before Wallace to read aloud excerpts from some of Darwin's letters and notes to them which dealt with his theory of evolution..." And this last quotation comes from the notes for a college course on evolution!
In short, there is still work to do. Earlier I implied that one of the main reasons that Wallace's work has been difficult to assess is the sheer bulk of his writings, and the fact of their being on so many subjects. Few investigators have done more than sample from his overall oeuvre, and in Wallace's case such efforts run the danger of producing conclusions that are based more on 20-20 hindsight resulting from the priority of Darwin's work than on Wallace's own thoughts.
In the time I have here it will not be possible to detail the overall approach to Wallace's world view I have been working out. I should at least like, however, to plant a few seeds of doubt as to whether the current model provides an adequate framework for appreciating his contribution. Wallace, we know, was an evolutionist as far back as 1844 or 1845, the time of his reading of Robert Chambers's Vestiges of the Natural History of Creation. We also know that by 1855 he was ready to promote an evolutionary biogeographic model--in the form of the Sarawak 'On the Law...' paper--in print. Further, there seems to be no reason to disbelieve his own words describing the revelation--natural selection--that came to him in early 1858 during that famous bout with malaria. And we may truly believe in his full support for the theory from that point on to the end of his days.
I believe, however, that a careful study of Wallace's writings--that is to say, all of his writings--leads one to question the common wisdom that his ideas on evolution in general describe a rather straight line development up through 1858, and a major retrenchment thereafter. To the contrary, it appears to me that before 1858 Wallace's position on the nature of adaptation had steered him quite away from a natural selection-like interpretation of development, and instead in a more teleological, even Newtonian, direction. This latter path had resulted from his steadfast resistance to the notion that a general model of the process of adaptation was obtainable--it appeared to Wallace that adaptive functions were quite unrelated to phylogenetic station, and that to argue otherwise was Creationist. Further, he had already come to the conclusion that many human adaptive traits could not be linked directly to environmental causal agents. When in 1858 the principle of natural selection finally occurred to him, it provided a solution to the first problem, but not to the second. His exploration of Spiritualism a few years later provided the final piece to the puzzle, allowing him to view both physical and mental adaptations in causally generalizable terms.
I believe I can make this argument in a variety of ways and in some detail at this point, but for the present I will concentrate on aspects of two related items only: Wallace's supposed post-1858 support of the Darwinian model of natural selection, and what I view as his early resistance to the notion of necessary utility of adaptive structures.
When Wallace returned home to England in 1862 he was something of a celebrity among naturalists. The role he had played in Darwin's publication of On the Origin of Species was well known, at the very least, to insiders in the movement, and they soon embraced his efforts supporting the cause. It is usually thought that Wallace's support for Darwin in the years immediately following 1858 was more or less total, and that he only came to doubt certain tenets of the theory by the mid-1860s. Evidence exists, however, that should lead us to question this understanding.
It may first be noted that Wallace--a man who produced in sum over 10,000 pages of writings, and who never published fewer than ten works in any two year period over the last sixty years of his life--wrote not a single word on the subject of natural selection between February of 1858 (the Ternate essay) and the fall of 1863, when he penned his classic analysis on the manner of construction of bee cells. Indeed, with one or two rather trivial exceptions, his writings during this period hardly mention the subject of evolution in any context, instead concentrating on biogeographical subjects of the kind discussed in the 1855 'On the Law...' essay. Why, we should ask ourselves, was this the case? Why would a man whose every fibre of being had been engaged for some fifteen years in an attempt to answer the question of how evolution took place, suddenly come up short when the opportunity to make his views known at last emerged? Could it possibly be that the answer to the question that he (and Darwin) had set forth did not completely satisfy him, and that he wished to look at the matter further before putting himself on record?
I think that this was in fact the case, and that the 'On the Tendency...' essay represented an interim stage in his thinking only. He may well never have published it--at least in the form that was sent to Darwin--had he had the chance to fully control its fate. Fortifying this impression is an interesting series of events, previously unnoticed, concerning Wallace's future referrals to the work.
In 1869 the German zoologist Adolf Bernhard Meyer sought Wallace's permission to publish a German translation of the Ternate essay. In a letter to Meyer (later itself reprinted in Nature in 1895), Wallace wrote "As soon as my ague fit was over I sat down, wrote out the article, copied it, and sent it off by the next post to Mr. Darwin. It was printed without my knowledge, and of course without any correction of proofs. I should, of course, like this act to be stated." The situation was in fact so stated, as a note to the text, when the translation was printed the next year, but apparently this was not enough to assuage Wallace's sense of historical responsibility. When the essay was reprinted in the monograph collection Natural Selection and Tropical Nature in 1891, Wallace added a single note to it on page 27: "'And that of their offspring' should have been added. But it must be remembered that the writer had no opportunity of correcting the proofs of this paper."
Three mentions of the matter in print were still not enough for him. In the article "The Dawn of a Great Discovery," published in 1903, Wallace stated the situation as follows: "...in the two succeeding evenings [I] wrote it out in full, and sent it by the next post to Mr. Darwin... I also asked him, if he thought well of it, to show it to Sir Charles Lyell, but I said nothing about its publication." Wallace was now eighty years old, but two years later, in Volume One of My Life, he raised the issue yet again: "The paper is reprinted in my Natural Selection and Tropical Nature, and in reading it now it must be remembered that it was but a hasty first sketch, that I had no opportunity of revising it before it was printed in the journal of the Linnean Society..."
These are a lot of apologies for what is arguably among the most influential essays in the history of human thought. Did Wallace possibly feel his words had not been taken up entirely as he intended? If so, what were his real intentions?
In 1853, as part of his book A Narrative of Travels on the Amazon and Rio Negro, Wallace wrote as follows:
"It must strike every one, that the numbers of birds and insects of different groups, having scarcely any resemblance to each other, which yet feed on the same food and inhabit the same localities, cannot have been so differently constructed and adorned for that purpose alone. Thus the goat-suckers, the swallows, the tyrant flycatchers, and the jacamars, all use the same kind of food, and procure it in the same manner: they all capture insects on the wing, yet how entirely different is the structure and the whole appearance of these birds!... What birds can have their bills more peculiarly formed than the ibis, the spoonbill, and the heron? Yet they may be seen side by side, picking up the same food from the shallow water on the beach; and on opening their stomachs, we find the same little crustacea and shell-fish in them all. Then among the fruit-eating birds, there are pigeons, parrots, toucans, and chatterers,--families as distinct and widely separated as possible,--which yet may be often seen feeding all together on the same tree; for in the forests of South America, certain fruits are favourites with almost every kind of fruit-eating bird. It has been assumed by some writers on Natural History, that every wild fruit is the food of some bird or animal, and that the varied forms and structure of their mouths may be necessitated by the peculiar character of the fruits they are to feed on; but there is more of imagination than fact in this statement: the number of wild fruits furnishing food for birds is very limited, and the birds of the most varied structure and of every size will be found visiting the same tree."We find in this early passage evidence that Wallace had rejected the notion of necessary one-to-one association between particular environmental influences and particular adaptations, and between particular adaptations and particular evolutionary lineages. Just how far he would take this bias is evident in the following excerpt from "On the Habits of the Orang-Utan of Borneo," an article published in 1856:
"...Do you mean to assert, then, some of my readers will indignantly ask, that this animal, or any animal, is provided with organs which are of no use to it? Yes, we reply, we do mean to assert that many animals are provided with organs and appendages which serve no material or physical purpose. The extraordinary excrescences of many insects, the fantastic and many-coloured plumes which adorn certain birds, the excessively developed horns in some of the antelopes, the colours and infinitely modified forms of many flower-petals, are all cases, for an explanation of which we must look to some general principle far more recondite than a simple relation to the necessities of the individual. We conceive it to be a most erroneous, a most contracted view of the organic world, to believe that every part of an animal or of a plant exists solely for some material and physical use to the individual,--to believe that all the beauty, all the infinite combinations and changes of form and structure should have the sole purpose and end of enabling each animal to support its existence,--to believe, in fact, that we know the one sole end and purpose of every modification that exists in organic change, and to refuse to recognize the possibility of there being any other. Naturalists are too apt to imagine, when they cannot discover, a use for everything in nature... ...we believe that the constant practice of imputing, right or wrong, some use to the individual, of every part of its structure, and even of inculcating the doctrine that every modification exists solely for some such use, is an error fatal to our complete appreciation of all the variety, the beauty, and the harmony of the organic world."The preceding words may come as something of a shock to those who are used to thinking of Wallace in hyperselectionist terms. One concludes from writings such as these (and there are some others that can be pointed to) that Wallace was having trouble working out a process model of evolutionary change because he had been unable to disabuse himself of the notion that necessary utility of adaptations was a theoretical dead-end leading to Creationism. When finally he did reassess his logic--with the help of Malthus--to derive the theory of natural selection, he found himself with a model that explained what he had thought for many years to be impossible to explain: how all individual adaptations might be functional, yet unpreordained. But the new model still could not explain how wholly creative adaptations--that is, the "higher faculties" of humankind--could come about. At best, the natural selection concept, with its survival of the fittest tenet linked to environmental driving forces, could be used to separate out that class of adaptive mechanisms that truly was a reactive response from that class that was not. And thus, the following early comments in the Ternate essay:
"...it is the object of the present paper to show that [the] assumption ["that varieties occurring in a state of nature are in all respects analogous to or even identical with those of domestic animals, and are governed by the same laws as regards their permanence or further variation"] is altogether false, that there is a general principle in nature which will cause many varieties to survive the parent species, and to give rise to successive variations departing further and further from the original type, and which also produces, in domesticated animals, the tendency of varieties to return to the parent form."I suggest that we need to take a closer look at the wording of this essay, in particular its lack of mention of how humankind might fit into the equation. This absence of mention has been interpreted by historians such as Schwartz and Kottler as indicating that as of 1858 Wallace recognized no distinction between the evolutionary situation of man and the rest of the living world, and therefore had not bothered to draw man into the discussion. This being so, of course, it is easy enough to conclude that Wallace's later treatments, which soon embraced preternatural causal agents, constituted a 'change of mind' on his part. But it is at least as reasonable to think that he kept man out of the 1858 discussion deliberately. Certainly, he had been just as profoundly interested in the evolutionary situation of humankind as he had other living things (we know this from his letters to his confidante Bates); moreover, it is clear that he had connected the historical biogeography model expressed in 'On the Law...' to the development of the human species (from comments made in several places, especially the aforementioned 'On the Habits of the Orang-Utan of Borneo'). This leads me to suspect that he viewed his 1858 'law' as being something quite distinct from--not just an extension of--his 1855 'law': distinct enough, in fact, that he was initially unwilling to associate the lines of argument and evidence of the one with the other.
To summarize... Wallace's writings up to 1858 suggest to me that he had adopted a rather unorthodox form of teleological thinking in which evolution was viewed as proceeding in response to some final cause whose global influence overrode biologically proximate causes. In the years before 1858 he had not been deliberately searching for a theoretical model of the proximate causes of organic change, largely because this approach seemed to presuppose adaptational first causes. The natural selection concept provided him with a proximate causes model, but not one that could explain the emergence of uniquely human qualities. Thus, Wallace's early reluctance to advance natural selection-based explanations, and the later re-emergence in his writings of a global evolutionary position, now embracing characteristics of human development.
Copyright 1999 by Charles H. Smith. All rights reserved.