Darwin and Divergence: The Wallace Connection - Darwin... · Darwin and Divergence: The Wallace Connection 3 As Kohn puts it, "When and how Darwin came to formulate the principle

Darwin and Divergence: The Wallace Connection

BARBARA G. BEDDALL

Crosslands, Box 90 Kennett Square, Pennsylvania 19348

Divergence of character has a double purpose and use. In the first place it enables a species which is being overcome by rivals, or is in process of extinction by enemies, to save itself by adopting new habits or by occupying vacant places in Nature. This is the immediate and obvious effect of all the numerous examples of divergence of character which we have pointed out. But there is another and less obvious result, which is, that the greater the diversity in the organisms inhabiting a country or district the greater will be the total amount of life that can be supported there. Hence the continued action of the struggle for existence will tend to bring about more and more diversity in each area.

Alfred Russel Wallace, Darwinism, 18891

In late April 1857, Charles Darwin received his first letter from the traveling naturalist Alfred Russel Wallace, a letter written on October 10, 1856, from Celebes, an island in the Malay Archi- pelago. A bit more than five months later, on September 5, Darwin wrote out and sent to the American botanist Asa Gray a concise outline of his theories, concluding with what he called his principle of divergence. It seems to be generally agreed by scholars that this was Darwin's first full articulation of this principle, and its formulation is considered an important step in the development of his theories; the rare unanimity on this score does not, however, extend to the theories proposed to explain the events that preceded it.

Matters of scientific priority are frequently controversial. One of the most famous cases concerns the respective roles of Darwin

1. Alfred Russel Wallace, Darwinism: An Exposition of Natural Selection, with Some oflts Applications (New York: Humboldt, 1889), p. 77.

Journal of the History of Biology, vol. 21, no. 1 (Spring 1988) pp. 1--68. © 1988 by Kluwer Academic Publishers.

2 BARBARA G. BEDDALL

and Wallace regarding the theory of natural selection, as well as a principle of divergence. It is not surprising that in recent years new hypotheses about their relationship should have been suggested. What is surprising is that questionable tactics are being approved, in particular "delicate arrangements" and "editorial manipulation," to help in the resolution of a problem that is, it will be held here, essentially unresolvable. The present study will attempt to clarify the situation through a close examination of the relevant hypotheses.

This paper is organized as follows: I. Recent Publications; II. Wallace's 1855 paper; III. 1855--1857; IV. 1858--1859; Chronology.

I. RECENT PUBLICATIONS

Among recent works treating the discovery of a principle of divergence are the following: Arnold C. Brackman, A Delicate Arrangement (1980); John L. Brooks, Just before the Origin (1984); Janet Browne, "Darwin's Botanical Arithmetic and the 'Principle of Divergence,' 1854--1858" (1980), and The Secular Ark (1983); Howard E. Gruber, Darwin on Man (1974); H. Lewis McKinney, Wallace and Natural Selection (1972); Dov Ospovat, The Development of Darwin's Theory (1981); and Silvan S. Schweber, "Darwin and the Political Economists" (1980). Also joined in the discussion are the review of Brackman's book by David Kohn (1981) and those of Brooks's book by Peter Bowler (1984) and Gareth Nelson (1984), as well as Barbara G. Beddall, "Wallace, Darwin, and the Theory of Natural Selection" (1968). Only two authors, Brackman and Brooks, recognize any substan- tial role for Wallace; McKinney touches only lightly on divergence, while Beddall does not discuss it at all. 2

2. Arnold C. Brackman, A Delicate Arrangement: The Strange Case of Charles Darwin and Alfred Russel Wallace (New York: Times Books, 1980); John Langdon Brooks, Just before the Origin: Alfred Russel Wallace's Theory of Evolution (New York: Columbia University Press, 1984); Janet Browne, "Dar- win's Botanical Arithmetic and the 'Principle of Divergence,' 1854--1858," J. Hist. Biol., 13 (1980), 53--89; idem, The Secular Ark: Studies in the History of Biogeography (New Haven: Yale University Press, 1983); Howard E. Gruber, Darwin on Man: A Psychological Study of Scientific Creativity, Together with Darwin's Early and Unpublished Notebooks, transcribed and annotated by Paul H. Barrett (New York: Dutton, 1974); H. Lewis McKinney, Wallace and Natural Selection, Yale Studies in the History of Science and Medicine, no. 8 (New Haven: Yale University Press, 1972; authorized facsimile, Ann Arbor: University

Darwin and Divergence: The Wallace Connection 3

As Kohn puts it, "When and how Darwin came to formulate the principle of divergence is the subject of intense historical re- search. ''3 More recently yet, David Oldroyd has remarked: "A point that must be emphasized is that even now, after all the efforts of the Darwin Industry in recent years, we still cannot say precisely how Darwin arrived at his theory. ''4 It will be the purpose of this paper to suggest alternatives or additions of various kinds to present views; for example, I will discuss the obvious unevenness in treatment accorded Wallace and Darwin, particularly by the Darwin scholars represented here.

But why should Wallace be included? There is a documented Wallace connection that, despite efforts to delineate it, still remains to be properly identified, a strand running concurrently with other recognized influences. Unfortunately, Wallace has not been well served by claims that are at times either exaggerated, or too narrowly focused, or not well founded. Brackman and Brooks, whose books contain much otherwise excellent material, have both made claims that Wallace never made himself. Wallace is the loser in the resulting controversy, as he has been made to suffer for the sins of his supporters. This extends even to Wallace's 1858 contribution to the "joint papers" read before the Linnean Society on July 1 of that year. Kohn remarks, for example, that

Microfilms International, 1984); Dov Ospovat, The Development of Darwin's Theory: Natural History, Natural Theology, and Natural Selection, 1838--1859 (Cambridge: Cambridge University Press, 1981); Silvan S. Schweber, "Darwin and the Political Economists: Divergence of Character," J. Hist. Biol., 13 (1980), 195--289. Reviews: Peter J. Bowler, "Wallace and Darwinism," Science, 224 (1984), 277--278 [a review of Brooks above]; David Kohn, "On the Origin of the Principle of Diversity," Science, 213 ( 1981), 1105 -- 1108 [a review of Brackman above]; Gareth Nelson, "Just before the Origin," Syst. Zool., 33 (1984), 248--249 [a review of Brooks above]. In addition: Barbara G. Beddall, "Wallace, Darwin, and the Theory of Natural Selection: A Study in the Development of Ideas and Attitudes," J. Hist. Biol., 1 (1968), 261--323; Frederick Burkhardt and Sydney Smith, eds. A Calendar of the Correspondence of Charles Darwin, 1821--1882 (New York: Garland, 1985) (letter numbers used throughout this paper are taken from the Calendar; see below, n. 176).

3. Kohn, "Origin of Principle," p. 1105. 4. For a recent summarizing of the literature on divergence, see David R.

Oldroyd, "How Did Darwin Arrive at His Theory? The Secondary Literature to 1982," Hist. Sci., 22 (1984), 353--357, 360, 373n44. Oldroyd notes that "there have been some insinuations and accusations in the literature that Darwin filched the divergence principle from Wallace . . . . And now that we have Dov Ospovat's reconstruction of how Darwin arrived at the principle, the accusations against Darwin on this matter can, I think, be discounted" (p. 353).


Hooker and Lyell, however, did go one step further. Brackman is right when he says that they manipulated the order of submission (without Darwin's knowledge) by putting Darwin's pieces before Wallace's paper. By placing the documents in the chronological order of their composition they favored Darwin's priority over Wallace's. No doubt they colored the judgment of history. Did this act constitute a conspiracy? No, just a delicate arrangement?

More recently, Nelson, in reviewing Brooks's book, has taken this argument still further:

In particular, history has given Darwin priority for the theory of evolution by means of natural selection. Historians agree and approve that such was arranged in part through editorial manipulation, by Darwin's friends Lyell and Hooker, of an essay in manuscript sent in 1858 by Wallace, who was in the Moluccas, to Darwin in England. 6

- - this last a startling conclusion drawn, it would appear, from Kohn above. But the approval of such methods strongly implies their necessity, at least on occasion, which is itself a distasteful conclusion in what might be called Lyell's legacy.

Two considerations are combined here. The first is that Lyell acted precipitately in presenting the joint papers at a special meeting of the Linnean Society, in the process displacing the paper that George Bentham had been scheduled to present at the canceled meeting of June 17. The second is, that how these arrangements were made is still unknown, and much of the material that might explain the details is missing. It is the conse- quent uncertainty that attracts attention.

In spite of all this, however, Wallace is quite well able to stand on his own feet. Indeed, in 1985 "the largest entomological expedition ever mounted to study the insects of Indonesia's rainforest" was named "Project Wallace" in his honor by the Royal Entomological Society, of which Wallace was once the president, in celebration of its 150th aimiversary. 7 Furthermore, there is a growing recognition of the many differences between the work of Darwin and that of Wallace, and thus of the many useful contribu-

5. Kohn, "Origin of Principle," p. 1108. 6. Nelson, "Just before the Origin," p. 248. 7. Bill Knight and Chris Schofield, "Sulawesi: An Island Expedition," New

Scientist, 105 (January 3, 1985), 12--15.


tions made by Wallace quite apart from Darwin's; these have been pointed out by Bowler, Brooks, Kohn, Ernst Mayr, and others, and are well worth investigation.

M o d e m Theories

Accounts of various theories about a principle of divergence and its discovery follow, beginning with the most recent:

Brooks (1984) told Brackman that " 'the heart of my hypothesis on the Wallace-Darwin relationship is that when Wallace mailed his manuscript to Darwin, Darwin received it May 18, 1858,'" not June 18 as commonly supposed. 8 Not only did this enable Darwin to make use of it, according to Brooks, it also served to recall Wallace's 1855 paper to mind, leading Darwin to take ideas from it, including the tree analogy and diagram. The papers in question are "On the Law Which Has Regulated the Introduction of New Species" and "On the Tendency of Varieties to Depart Indefinitely from the Original Type" (1855 and 1858, respectively). 9

That Darwin needed this reminder can easily be disproved, for he never had a chance to forget the 1855 paper. Not only did Lyell urge Darwin to begin writing for publication on account of it, but Wallace himself initiated a correspondence with Darwin, his first letter reaching Darwin in late April 1857. Darwin wrote two letters to Wallace in 1857 (in May and December) and in both he mentioned the 1855 paper in the Annals and Magazine o f Natural History.

Brooks's theories about the use made by Darwin of Wallace's ideas require an arrival date for Wallace's 1858 manuscript sometime in May, either on the eighteenth or on the twenty-eighth or twenty-ninth. This would have given Darwin time to incorporate various ideas into his own text, in particular into his section on divergence in what became his Natural Selection, before its completion on June 12.1°

Three points on dates should be mentioned here: (1) The letter from Darwin to Lyell informing him of the arrival of Wallace's manuscript is usually dated June 18, but the month was added

8. Brackman, Delicate Arrangement, p. 348. 9. Alfred Russel Wallace, "On the Law Which Has Regulated the Introduc-

tion of New Species," Ann. Mag. Nat. Hist., 2nd Ser., 16 (September 1855), 184--196; idem, "On the Tendency of Varieties to Depart Indefinitely from the Original Type," J. Linn. Soc. London ( Zool.), 3 (1858), 53--62.

10. Brooks, Before the Origin, pp. 251--257. Brackman is barely mentioned.


later by another hand. Perhaps, says Brooks, the month was May. Or, if received in June, perhaps it was written in May and mailed later.11 But there is no real proof for these suggestions.

(2) The accepted date for the receipt of Wallace's 1858 paper is also June 18 (see above). McKinney has shown that a letter from Wallace to Frederick Bates (the brother of Wallace's old friend Henry Walter Bates), presumably mailed at the same time as the manuscript, was received in London on June 3. According to Brooks, this includes an unexplained two-week delay. 12 But could not other such delays account for an arrival on June 18?

On an uninterrupted voyage from the Far East, the manuscript could have reached London on May 14. The minimum travel time from Ternate to London was a little over two months -- that is, March 9 to May 14, according to Dutch mailboat schedules obtained by Brooks) 3 Thus, Brooks considers that "May 17--18 is the most likely time for Wallace's letter and manuscript to have reached Darwin's hands." With a two-week delay, the letter and paper would have arrived on May 28--29.14 Although there is no solid proof for either of the May dates, Brooks prefers the earlier date - - but for reasons that are both subjective and far from compelling, not to mention tautological, as they apply only to what happened after the paper's arrival:

First, there is the tone of Darwin's "18th" letter to Lyell; it sounds honest and despairing . . . . (A second letter, dated "Friday," leaves a quite different impression.) The second reason is the length of time required to make the long insertions into the "Natural Selection" chapter. 15

But this ignores the fact that the addition on divergence in Darwin's Natural Selection is closely related to the letter to Gray in the previous September, not to Wallace's 1858 paper. In this case, the results would be the same whether the paper had arrived early or not. To have any validity, Brooks's belief requires independent proof of the early arrival. But, as the date cannot be unequivocally determined, this important point is left hanging, as Brooks himself acknowledges. An arrival date of June 18 cannot

11. Ibid., pp. 251--252. 12. McKinney, Wallace, pp. 138--141; Brooks, Before the Origin, p. 256. 13. Brooks, Before the Origin, pp. 254--256. 14. Ibid., p. 256. 15. Ibid., p. 257.


yet be ruled out, while an established date of June 18 would destroy Brooks's argument.

(3) From pencil marks made by Darwin on his personal copy of Wallace's 1855 paper, Brooks concludes that some were made in May--June of 1858; but this judgment is based on some differences in these marks, evidence that is far from convinving. 16

Bowler (1984) remarks that "Brooks goes on to claim that Wallace's views on branching evolution played a key role in stimulating Darwin to develop his own principle of divergence. This is not a new idea. It was advanced by Arnold Brackman in 1980. ''17 This leads into the subject of the tree analogy and diagram; but this was not a new idea for Darwin, who had been familiar with it since at least 1837 (this will be more fully discussed below).

Bowler is ambiguous, probably unintentionally, when he says that "according to Brooks, though, Darwin did not complete his theory of divergence through ecological specialization until Wal- lace's 1858 paper led him to reread the earlier one. ''18 Brooks specifically says that "it should be emphasized here that Darwin's view of the significance of ecological diversity in causing divergence and then extinction is entirely his own; it has no counterpart in Wallace's conceptions, either in 1855 or in 1858," but was accepted by him later (see the opening quotation)) 9

Browne (1980, 1983) claims that until mid-1857 Darwin was not even aware of a need for a "principle" of divergence. He "had established this principle by the end of August 1857. Yet it had meant nothing to him the previous March, when he was putting the final touches to Chapter VI." This was brought about, in her opinion, by a reconsideration of the calculations for his botanical arithmetic in mid-July, which led to his principle of divergence as stated in the letter to Asa Gray on September 5, 1857. 20

Ospovat (1981; not discussed in either Brooks 1984 or Browne 1983) is of the opinion that Darwin began his work on a principle of divergence in September 1854. It grew "out of work on classi-

16. Ibid., pp. 246--248. 17. Bowler, "Wallace and Darwinism," p. 278; Brackman, Delicate Arrange-

ment, pp. 51--52. 18. Bowler, "Wallace and Darwinism," p. 278. 19. Brooks, Before the Origin, p. 243. 20. Browne, SecularArk, pp. 211--213.


fication," and it culminated two years later when he succeeded in integrating his principle of divergence into the theory of natural selection. He did this by showing that "large genera are increasing," that "the most diverse forms can best succeed," and that "diversity is beneficial. ''2~ Further: "In the process of integrating this principle into the theory of natural selection, Darwin came to see it as implying a tendency toward ecological diversification and hence ecological rather than geographical speciation." 22

"If pressed," Ospovat remarks, "to locate more precisely the point between November 1854 and March 1857 at which the transformation [to his revised theory] occurred, I would say the second half of 1 8 5 6 . . . about September) 3

Ospovat scarcely mentions Wallace. Nevertheless, it is Ospo- vat's theories with which the theories to be proposed here are the most compatible. Indeed, the present paper might be considered as contributing towards filling in the background of the development of Darwin's theories as delineated by Ospovat.

Kohn (1981) raises the following points in reviewing Brack- man's book: unacknowledged borrowings by Darwin; Darwin's indifferent response to parts of Wallace's 1855 paper, in sharp contrast to the favorable reactions of Lyell and Edward Blyth; Lyell's urgent advice in May 1856 that Darwin begin to write for publication and priority; the Darwin commentary on his personal copy of Wallace's 1855 paper; Darwin's dilatory answer to Wallace's first letter; Darwin's letter to Gray in September 1857; May arrival dates for Wallace's 1858 manuscript; revisions made by Darwin in his Natural Selection manuscript on divergence; material that is apparently missing; Wallace's subordinate role in the Linnean Society papers; and Darwin and priority. Various of these points will be considered in the following sections of this paper. 24

Brackman (1980) notes the early arrival dates for Wallace's 1858 manuscript suggested by Brooks (May) and McKinney (early June), and himself suggests June 3--4, 8, or 14. 25 Brooks, he says,

21. Ospovat, Darwin's Theory, pp. 171,177, 179, 180. 22. Ibid., p. 189. 23. Ibid.,p. 192. 24. Kohn is considered by Nelson ("Just before the Origin," p. 248) to have

used "strong words" in criticizing Brackman's book; he is considered by Oldroyd ("Darwin's Theory," pp. 353, 372n322) to have "effectively demolished" it with his review in Science in 1981.

25. Brackman, Delicate Arrangement, pp. 16--21.


"is convinced that Darwin drew his concept of divergence from Wallace's Sarawak Law [1855] and the Ternate Essay [1858]. "26 As for Brackrnan himself, he claims that "in 1857 the impact of Wallace's work apparently dawned upon him, and Darwin began to work out his theory of divergence. ''27 Further, he suggests that the complete solution to the problem of divergence did not occur to Darwin until after the early arrival of the 1858 manuscript. He bases these arguments on a letter from Darwin to Joseph Hooker on June 8, which was sent, he claims, five days after the arrival of the Bates letter - - and, presumably, of the Wallace paper as well - - on June 3:28

I will try to leave out all allusion to genera coming in and out in this part [the long chapter on variation in a state of nature], till when I discuss the "Principle of Divergence," which, with "Natural Selection," is the keystone of my book. 29

Alternatively, according to Brackman, the manuscript arrived on June 8, the day of Darwin's letter to Hooker, or on the "14th Pigeons (interrupted), ''3° but what is to be made of the letter to Hooker in this case?

I agree with Kohn when he says that here "Darwin was referring to the organization of his book, not announcing the discovery of a new principle. ''3~ Nevertheless, Brackman interprets this to mean that Darwin was "elated to report that he had at last resolved the frustrating problem of how species diverge in nature. ''32 An early June arrival, he asserts, would have permitted Darwin a week or more of time in which to "rework a problem" of divergence "that had baffled him for almost two decades." The result, he claims, was the forty-plus-page interpolation (24 pages in the published edition of Darwin's Natural Selection, pp. 226--250) on his principle of divergence, 33 which now included tree diagrams (as

26. Ibid., p. 18. 27. Ibid., p. 51. 28. Ibid., p. 17. 29. Charles Darwin, More Letters of Charles Darwin: A Record of His Work

in a Series of Hitherto Unpublished Letters, ed. Francis Darwin and A. C. Seward, 2 vols. (New York: Appleton, 1903), I, 109; ( # 2282).

30. Brackman, Delicate Arrangement, p. 19; Charles Darwin, "Darwin's Journal," ed. Gavin de Beer, Bull. Brit. Mus. (Nat. Hist.), Hist. Ser., 2 (1959), 14.

31. Kohn, "Origin of Principle," p. 1107. 32. Brackman, Delicate Arrangement, p. 17. 33. Ibid., p. 350.


far as this goes, Brooks would agree, except for the June date). The letter to Hooker on June 8 "indicates," says Brackman, "that [Darwin] may have made the discovery shortly before that date. Did he make it after reading Wallace's Ternate Paper -- assuming that the latter had arrived five days earlier? Or did Darwin make his discovery independently?" 34

Brackman also notes "Darwin's failure to uncover the principle of divergence until 1858," as explicated by Schweber, but in so doing he misinterprets Schweber's reference to "a third stage" (of the development of Darwin's theory of natural selection, not his principle of divergence), which "occurred in 1858 with the amalgamation of the tree-of-life visualization of the process of speciation." This misinterpretation provides Brackman with further support for his belief that Darwin did not work out his principle of divergence until June 1858. 35

But for all this supposed flurry of activity in the month of June 1858, Darwin was represented at the Linnean Society meeting, not by the forty-page insert (about which he had written to Hooker on June 8), but by the outline sent to Gray the preceding September. Even if Darwin had copied from Wallace's 1858 paper, he would have gained no priority rights for any of the ideas found there. These were first given to the world by Wallace, whose paper was read at the Linnean Society meeting on July 1. As explained in section II below, the principle of divergence found in the letter to Gray was based on a still earlier version; it was itself amplified in Darwin's Natural Selection (not published until 1975), and later on in the Origin as well.

Brackman maintains that "it was Wallace's manuscript that contained the first complete exposition, in writing, of descent and divergence with modification through variation and natural selection. ''36 He seems to underrate the fact that this very paper was published as written, becoming publicly available in August 1858. One might feel that Wallace's paper should have been placed first at the Linnean Society meeting (about which there can be honest disagreement), without at the same time suggesting that Darwin took Wallace's ideas for himself, which is an entirely different matter. In fact, any particular ideas expressed by Wallace in his 1858 paper (and there were more than a few, owing to the many differences in detail) automatically had priority, by virtue of prior

34. Ibid., p. 18. 35. Ibid., p. 350; Schweber, "Darwin and the Political Economists," pp.

213n50, 288. 36. Brackman, Delicate Arrangement, p. 19.


publication, over any similar ideas later expressed by Darwin, stolen or not.

Schweber (1980) takes a different tack. Of crucial importance in the development of Darwin's principle of divergence, he holds, was Henri Milne-Edwards's Introduction ~ la zoologie grnrrale (1851). 37 This author and his works were well known to Darwin. But "when Darwin claimed to have obtained the principle of divergence around 1852 [a date suggested by Gavin de Beer on the basis of a letter Darwin wrote to Bentham], he seems," writes Schweber, "to have forgotten the insights he had gained in 1837 and in the period after he read Malthus. ''38 De Beer himself, it should be noted, claims that what Darwin "was referring to in 1852 was not the fact of divergence, but a causal explanation of how it occurs and how it increases." 39

If the year 1852 is accepted as the date of Darwin's discovery of the principle itself, awkward problems arise. Schweber notes: "That the insight into divergence of character may have occurred twice has previously been suggested by Gruber, Darwin on Man, p. 117" - - perhaps, as Mayr has suggested, because Darwin's later approach differed from his earlier one? °

Schweber traces many possible sources and influences on Darwin's thinking, but has little to say about the period from 1852 to 1858. In any event, he says that "there can be no doubt that Darwin had the concept of divergence of character before May or June 1858. The letter of September 1857 to Asa Gray would be sufficient proof of that."41

According to Schweber, Darwin's development of his theory of natural selection occurred in three stages: (1) the period ending in 1844; (2) the influence of Milne-Edwards (up to 1852); and (3) "the amalgamation of the tree-of-life visualization of the process of speciation" in 1858. 42

Gruber (1974) begins with the tree analogy found in Darwin's first notebook in 1837. That Darwin did not include this in either his 1842 or 1844 sketches, but did include it in his Natural

37. Schweber, "Darwin and the Political Economists," pp. 249--257. 38. Ibid., p. 220 and n. 70, 71. 39. Gavin de Beer, Charles Darwin: A Scientific Biography (Garden City,

N.Y.: Doubleday, 1965), p. 140. 40. Schweber, "Darwin and the Political Economists," pp. 220 and n. 70, 211

and n. 43. 41. Ibid., p. 213n50. 42. Ibid., pp. 287--288; Brackman, Delicate Arrangement, p. 350.


Selection, means to Gruber that it was forgotten in the interval and then rediscovered. However, he fails even to discuss the letter to Gray beyond saying that Darwin "confided in him about his theory of evolution two years before the publication of the Origin, in 1859. "43

Apparently, few people are aware of Darwin's markings on his personal copy of Wallace's paper. A small diagram of a tree of life found there closely resembles a diagram sketched by Darwin in his first notebook. This suggests a continuum, not a division, in the development of Darwin's theory, although Brooks claims that Darwin did not actually sketch it there until 185 8.44

McKinney (1972) established that it would have been possible for Wallace's 1858 manuscript to have arrived on June 3, because a letter sent by Wallace to Frederick Bates arrived in London on that date. If mailed at the same time, McKinney claims, the 1858 paper could have arrived at Down House on the same day - - but of the importance of this, he is unsure. 45 He also discusses the Darwin commentary on Wallace's 1855 paper, noting Darwin's ambivalent reactions to it. 46 As for the principle of divergence, he says that he "strongly agrees with Prof. Brooks that the subject of divergence bears close examination, especially Darwin's 'note on divergence' added to Ch. VI of the long version of the Origin," but he comes to no conclusions of his o w n . 47

Beddall (1968). The thrust of this paper is the development of Wallace's theories and the establishment of which of certain key letters and other material written at the time of the Linnean Society meeting were missing (as they had been for some time - - and indeed, most still are), as well as other details about the meeting itself. This paper was written before the present controversy on a principle of divergence arose. The conclusions reached in 1968 were directed at some of the more extravagant claims of writers like Loren Eiseley:

And so the story rests, with some questions still unanswered.

43. Gruber, Darwin on Man, pp. 117, 68. 44. Wallace, "On the Law," p. 186. The diagram was sketched on Darwin's

personal copy of the Annals and Magazine of Natural History in which Wallace's 1855 paper appeared.

45. McKinney, Wallace, pp. 139--141. 46. Ibid.,pp. 117--119. 47. Ibid., p. 141; McKinney also points out that Brooks's original argument

in 1968 "falls to mention the Asa Gray letter" (p. 141 n23).


Why did Wallace first write to Darwin? Why did Darwin send the outline of his theory of natural selection to Asa Gray? What became of the letters Darwin received from Wallace, Lyell, Hooker , and Gray? w h e r e is Wallace's manuscript? The answers are in the missing material, and what really happened must remain speculation. The fact that much other material is also missing does not invalidate the point that evidence to support some commonly accepted explanations is inadequate or lacking and that other explanations are clearly in error. 48

Only three of the pieces previously considered here to be missing have since turned up: Gray to Darwin, August 1857 ( # 2129, an unpublished fragment); Hooker to Darwin, July 13, 1858 ( # 2307, published by Huxley); Wallace to Hooker, Octobr 6, 1858 ( # 2337, in the possession of Quentin Keynes).

II. W ALLAC E 'S 1855 PAPER

[p.] 185 Wallace's paper: Laws of Geograph. Distrib. Nothing very new -- [p.] 186 His general summary "Every species has come into existence coincident in time & space with pre- existing species." - - Uses my simile of tree - - It seems all creation with him - - alludes to Galapagos [p.] 189 on even adjoining species being closest - - (It is all creation, but why does his law hold good; he puts the facts in striking point of view -- [p.] 194 argues against our supposed geological perfect knowledge -- Explains Rudimentary organs on same idea (I should state that put generation for creation & I quite agree) . . . .

Charles Darwin, handwritten commentary on Wallace's 1855 paper 49

In September 1855 there appeared in the Annals and Magazine of Natural History an important paper by Wallace, "On the Law Which Has Regulated the Introduction of New Species." Among its readers was Darwin, whose interest is signaled by the many marks and comments found on his personal copy -- in particular, by the comments added at the end of that volume of the Annals

48. Beddall, "Wallace, Darwin," p. 318. Note also the table of letters on pp. 319--323; see also n. 192.

49. Charles Darwin, handwritten commentary on Wallace's 1855 paper. Not discussed here are rudimentary organs or geological knowledge.


and repeated here (see above). The discussion that follows is organized around some of the more pertinent points.

[p.] 185 Wallace's paper: Laws o f Geograph. Distrib. Noth ing very new . . . alludes to Galapagos [p.] 189 on even adjoining species being closest. This was the first of Darwin's comments, and on a subject of great interest to him. Long before, he had written in his R e d N o t e b o o k that "when we see Avestruz two species. Certainly different, not insensible change. - - Yet one is urged to look to common parent? Why should two of the most closely allied species occur in same country?" And, in his first notebook on transmutation of species, that he looked "at two Ostriches as strong argument of possibility of such change; as we see them in space, so might they in time." 50

Wallace had phrased his own "law" on this subject as follows: "Every species has come into existence coincident both in space and time with a pre-existing closely allied species." 51 He noted in his 1855 paper that "when a group is confined to one district, and is rich in species, it is almost invariably the case that the most closely allied species are found in the same locality or in closely adjoining localities, and that therefore the natural sequence of the species by affinity is also geographical." 52

In his own notebook Wallace had objected to Lyell's assumption, in 1853, that, when conditions changed, "the animals & plants of Nor thern Africa would disappear, & the region would gradually become fitted for the reception of a population of species perfectly dissimilar in their forms, habits & organization." 53 That they were not became an important tenet of Wallace's law. "But have we not reason," Wallace asked, "to believe they would be modified forms of the previously existing Nor thern African species?" 54

It is small wonder that Lyell was struck with Wallace's paper, or that he saw instantly a connection between WaUace's law and

50. Charles Darwin, The Red Notebook of Charles Darwin, ed. Sandra Herbert (Ithaca, N.Y.: Cornell University Press, 1980), p. 71; Gavin de Beer, "Darwin's Notebooks on Transmutation of Species: Part I. First Notebook (July 1837--February 1838)," Bull. Brit. Mus. (Nat. Hist.), Hist. Ser., 2 (1960), 43. The Red Notebook was written in the first part of 1837.

51. Wallace, "On the Law," p. 186. 52. Ibid.,p. 185. 53. Alfred Russel Wallace, "Notebook, 1855--1859," MS, Linnean Society

of London, p. 50; Charles Lyell, Principles of Geology: or, The Modern Changes of the Earth and Its Inhabitants . . . . 9th ed. (London: Murray, 1853), p. 695.

54. Wallace, "Notebook," p. 50.


Darwin's natural selection, in April 1856, when Darwin first explained the latter to him. 55

Of special interest to Wallace was Darwin's 1845 account of the inhabitants of the Gakipagos Archipelago:

The only light which I can throw on this remarkable difference in the inhabitants of the different islands, is, that very strong currents of the sea running in a westerly and W.N.W. direction must separate, as far as transportal by sea is concerned, the southern islands from the northern ones; and between these northern islands a strong N.W. current was observed, which must effectually separate James and Albemarle Islands. As the archipelago is free to a most remarkable degree from gales of wind, neither the birds, insects, nor lighter seeds, would be blown from island to island. And lastly, the profound depth of the ocean between the islands, and their apparently recent (in a geological sense) volcanic origin, render it highly unlikely that they were ever united; and this, probably, is a far more important consideration than any other, with respect to the geographical distribution of their inhabitants. Reviewing the facts here given, one is astonished at the amount of creative force, if such an expression may be used, displayed on these small, barren, and rocky islands; and still more so, at its diverse and yet analogous action on points so near each other. I have said that the Gal~ipagos Archipelago might be called a satellite attached to America, but it should rather be called a group of satellites, physically similar, organically distinct, yet intimately related to each other, and all related in a marked, though much lesser degree, to the great American continent. 56

If Darwin had no solution to this puzzle, Wallace would pro- pose one to take the place of Darwin's "creative force":

Such phenomena as are exhibited by the Gahipagos Islands, which contain little groups of plants and animals peculiar to themselves, but most nearly allied to those of South America, have not hi therto received any, even a conjectural explanation.

55. Charles Lyell, Sir Charles Lyell's Scientific Journals on the Species Question, ed. Leonard G. Wilson (New Haven: Yale University Press, 1970), p. xlv.

56. Charles Darwin, Journal of Researches into the Natural History and Geology of the Countries Visited during the Voyage of H.M.S. Beagle round the World, 2nd ed. (London: Murray, 1845), p. 398 (emphasis added). This is a somewhat expanded version of what appeared in the first edition in 1839.


The GaNpagos are a volcanic group of high antiquity, and have probably never been more closely connected with the continent than they are at present. They must have been first peopled, like other newly-formed islands, by the action of winds and currents, and at a period sufficiently remote to have had the original species die out, and the modified prototypes only remain. In the same way we can account for the separate islands having each their peculiar species, either on the supposition that the same original emigration peopled the whole of the islands with the same species from which differently modified prototypes were created, or that the islands were successively peopled from each other, but that new species have been created in each on the plan of the pre-existing ones. 57

What Wallace still lacked, however, was a theory by which to explain his modified prototypes. Darwin, on the other hand, could say of the birds of the Gal~ipagos Islands that he supposed that "nearly all the birds had to be modified, I may say improved by selection in order to fill as perfectly as possible their new places. ''58 But Darwin never commented directly, either then or later, on Wallace's proposed solution in regard to the peopling of the Galfipagos Islands, even when corresponding with Wallace himself. And in the Origin (by which time Wallace had worked his theory out), he confined his identifying words to "a volcanic island," with no mention here of the GaNpagos:

If it can be shown to be almost invariably the case, that a region, of which most of its inhabitants are closely related to, or belong to the same genera with the species of a second region, has probably received at some former period immigrants from this other region, my theory will be strengthened; for we can clearly understand, on the principle of modification, why the inhabitants of a region should be related to those of another region, whence it has been stocked. A volcanic island, for instance, upheaved and formed at the distance of a few hundreds of miles from a continent, would probaly receive from it in the course of time a few colonists, and their descendants, though modified, would still be plainly related by inheritance to the inhabitants of the continent. Cases of this nature are common, and are, as we

57. Wallace, "On the Law," p. 188 (emphasis added). 58. Charles Darwin, Charles Darwin's Natural Selection: Being the Second

Part of His Big Species Book Written from 1856--1858, ed. Robert Stauffer (Cambridge: Cambridge University Press, 1975), p. 257.


shall hereafter more fully see, inexplicable on the theory of independent creation. This view of the relation of species in one region to those in another, does not differ much (by substituting the word variety for species) from that lately advanced in an ingenious paper [not further identified here or elsewhere in the Origin] by Mr. Wallace, in which he concludes, that "every species has come into existence coincident both in space and time with a pre-existing closely allied species." A n d I now know f rom correspondence, that this coincidence he attributes to generation with modification. 59

Darwin put this even more strongly in a letter to Wallace dated April 6, 1859: "You must remember that I am now publishing only an Abstract, and I give no references. I shall of course allude to your paper on Distribution; and I have added that I know from correspondence that your explanation of your law is the same as that which I offer."6°

How important these ideas were to Darwin can be judged from the following:

The most striking and important fact for us in regard to the inhabitants of islands, is their affinity to those of the nearest mainland, without being actually the same species. Numerous instances could be given of this fact. I will give only one, that of the Galfipagos Archipelago . . . .

The law which causes the inhabitants of an archipelago, though specifically distinct, to be closely allied to those of the nearest continent, we sometimes see displayed on a small scale, yet in a most interesting manner, within the limits of the same archipelago. Thus the several islands of the Galfipagos Archi- pelago are tenanted, as I have elsewhere shown, in a quite marvellous manner, by very closely related species; so that the inhabitants of each separate island, though mostly distinct, are related in an incomparably closer degree to each other than to the inhabitants of any other part of the world . . . .

The principle which determines the general character of the

59. Charles Darwin, On the Origin of Species, 1st ed. (London: Murray, 1859; facsimile reprint, Cambridge: Harvard University Press, 1964), pp. 354-- 355 (emphasis added).

60. James Marchant, Alfred Russel Wallace: Letters and Reminiscences (New York: Harper, 1916), p. 113 ( CA 2449).


fauna and flora of oceanic islands, namely, that the inhabitants, when not identically the same, yet are plainly related to the inhabitants of that region whence colonists could most readily have been derived, - - the colonists having been subsequently modified and better fitted to their new homes, - - is of the widest application throughout nature. We see this on every mountain, in every lake and marsh. 61

That Darwin was not overly generous in acknowledging the work of others, as seems apparent here, has been noted more than once. 62 Even Lyell complained, not only on his own account, but also on Wallace's - - in particular, in regard to the 1855 paper. "My dear Wallace," Lyell wrote on April 4, 1867,

I have been reading over again your paper published in 1855 in the Annals on "The Law Which Has Regulated the Introduc- tion of New Species;" passages of which I intend to quote, not in reference to your priority of publication [italics added; but what precisely did Lyell mean by this?], but simply because there are some points laid down more clearly than I can find in the work of Darwin itself, in regard to the bearing of the geological and zoological evidence on geographical distribution and the origin of species. I have been looking into Darwin's historical sketch [first added in 1861] thinking to find some allusion to your essay at page xx., 4th ed., when he gets to 1855, but I can find no allusion to it. Yet surely I remember some- where a passage in which Darwin says in print that you had told him that in 1855 you meant by such expressions as "species being created on the type of pre-existing ones closely allied," and by what you say of modified prototypes, and in the passage in which you ask "what rudimentary organs mean if each species has been created independently," etc., that new species were created by variation and in the way of ordinary generation. 63

Lyell apparently overlooked the brief recognition accorded by Darwin, mentioned above. Curiously, this was altered somewhat at a later date, appearing in the sixth edition of the Origin as follows:

This view of the relation of the species of one region to those of

61. Darwin, Origin (1859), pp. 397,399--400,403. 62. Beddall, "Wallace, Darwin," pp. 269, 312--314. 63. Marchant, Wallace, Letters, pp. 279--280.


another, does not differ much from that advanced by Mr. Wallace, who concludes that "every species has come into existence coincident both in space and time with a pre-existing closely allied species." And it is now well known that he attributes this coincidence to descent with modification. 64

There was never any mention of the title or date of Wallace's 1855 paper in the Origin, nor was it ever included in Darwin's own Historical Sketch, where other references were properly cited. "Nothing very new," Darwin's comment on Wallace's remarks on geographical distribution, seems more than a little disingenuous.

Uses my simile of tree. It is Brooks's claim that Darwin took the tree analogy from Wallace in 1857 and that its (apparently almost accidental?) elaboration in 1858 was an important step in the development of Darwin's principle of divergence (also called divergence of character). Confusingly, he claims that Darwin derived his tree diagram from Wallace's 1855 paper in 1858 (although it was sketched there by Darwin, not Wallace) and the tree analogy from the same paper in 1857 in his September letter to Asa Gray, overlooking Darwin's long-time familiarity with both the tree analogy and diagrams of it. 65

But why should Darwin have referred to it as "my ]italics added] simile of tree" if he had never heard or read about it before? In point of fact, as is well known, Darwin had used this simile himself in 1837, complete with diagrams, in the first of his notebooks on the "Transmutation of Species," a point entirely passed over by Brooks. "Organized beings," Darwin had written at the time,

represent a tree, irregulary branched; some branches far more branched, hence genera, - - As many terminal buds dying, as new ones generated. There is nothing stranger in death of species, than individuals . . . . The tree of life should perhaps be called the coral of life, base of branches dead, so that passages cannot be seen. 66

-- a point illustrated by the first of three diagrams, which resem-

64. Charles Darwin, On the Origin of Species, 6th ed. (1872; reissued New York: Collier, 1962), p. 371.

65. Brooks, Before the Origin, pp. 242--243, 246. 66. De Beer, "Darwin's Notebooks," pp. 43--47.


bles the diagram sketched by Darwin in the margin of his copy of Wallace's 1855 paper. 67

It is de Beer's opinion that this first notebook "contains a splendid discussion of the principle of branching and sub-branching of the evolutionary tree, and this shows that Darwin had already grasped fully the principle of divergence," although not everyone shares his interpretation. 68

Nor was Darwin the only person who was familiar with the tree analogy. Besides Richard Owen and Edward Forbes, 69 there was also the then still-anonymous author of the Vestiges of the Natural History of Creation, Robert Chambers. By means of a "simple diagram" the latter illustrated the main stem of life with offshoots for its diverging forms, remarking:

This diagram shews only the main ramifications; but the reader must suppose minor ones, representing the subordinate differences of orders, tribes, families, genera, etc., if he wishes to extend his views to the whole varieties of being in the animal kingdom. 7°

That Darwin was concerned that someone like Chambers could easily appropriate Darwin's ideas is demonstrated by his caution- ary words to Asa Gray in September 1857 (see below, section III).

Brooks presumes that Darwin was unfamiliar with the tree analogy before reading Wallace's 1855 paper; he comments on Darwin's marginalia as follows:

The third and remaining notation is the most relevant to our argument. As figure 11.2 shows, there is a straight dotted line alongside another dotted line which splits into three diverging

67. See Brooks, Before the Origin, p. 247, for an illustration of Darwin's marks. All the marks and remarks are found, of course, on Darwin's personal copy of Wallace's paper.

68. Gavin de Beer, introduction to "Darwin's Notebooks," p. 40 (see above, n. 50). See also Philip D. Gingerich, "Punctuated Equilibria -- Where is the Evidence?" Syst. Zool., 33 (1984), 335--338, for a brief and lucid account of the present status of Darwin's diagram as defined by an adherent of gradualism.

69. Ospovat, Darwin's Theory, p. 174. 70. Robert Chambers, Vestiges of the Natural History of Creation (London:

John Churchill, 1844; reprint, New York: Humanities Press, 1969), pp. 212-- 213. Lamarck also made use of the tree analogy and diagram, as pointed out by the referee of this paper; see Jean Baptiste Lamarck, Zoological Philosophy: An Exposition with Regard to the Natural History of Animals, trans. Hugh Elliot (New York: Hafner, 1963; originally published as Philosophie Zoologiqueqn 1809), pp. 178--179.


lines toward the bottom. And it can be seen from the figure that this diagram is opposite the text in which Wallace describes these two possible kinds of lineages. Note, too, that this passage had been marked by Darwin earlier but that the concept of simple and dive~ing lineages apparently had made no lasting impression, for it was not selected for the summary on the blue slip at the end of the Annals for 1855. Nor are the ideas detectable in Darwin's 1857 writings. 7~

That Darwin, for lack of comprehension, did not work this out until after the arrival of Wallace's paper in May 1858 (Brooks's date) is a pivotal argument essential to Brooks's hypothesis, but it cannot be sustained. Indeed, far from having "made no lasting impression," the ideas not otherwise "detectable in Darwin's 1857 writings" can be traced back to 1837 when Darwin opened his first transmutation notebook.

Brooks also suggests that Darwin's marginalia were made at two different times, indicated, he says, by apparent differences in the pencils used, the first occasion on first reading the paper, and the second in May or June 1858. 72 But how such otherwise indistin- guishable marks can be so neatly tied to particular dates is a mystery and a weakness in Brooks's theory. Nevertheless, Brooks uses these assumptions to claim that

this, I believe, substantiates the conclusion that on rereading Wallace's 1855 paper in May or June 1858 Darwin grasped the fuller significance of Wallace's statements. Further, I believe that the marginal diagram on page 186 is the prototype of the sole diagram of Darwin's "Natural Selection" manuscript [pp. 236--246] and therefore the prototype of the sole diagram in the Origin of Species [pp. 116--125]. 73

The last sentence could well be true as far as it goes - - that is, if one omits Darwin's 1837 notations -- but even so the result is Darwin's construction, not Wallace's.

What prompted this rereading? According to Brooks, it was the early arrival of Wallace's 1858 paper (a requirement of his theory) that gave Darwin time to peruse, and possibly to take from, Wallace's new paper; its early arrival also served to recall Wallace's

71. Brooks, Before the Origin, p. 246 (emphasis added). 72. Ibid.,p. 248. 73. Ibid.


1855 paper to Darwin's mind, he says. And it was as a result of this rereading that Darwin took the tree diagram, sketched in by himself, from the latter in the spring of 1858:

We are left, I believe, with the most likely stimulus for Darwin's restudy of Wallace's 1855 paper, namely, Wallace's concept of the dynamics of the origin of species as elaborated in his Ternate manuscript. This included explicit explanations for extinction and divergence. Darwin's marginal drawing on Wal- lace's 1855 paper, of simple and divergent lines of descent, is, I believe, the early result of that reexamination. It suggests the genesis of the diagram and text of the inserted folios, 26* through 26nn [pp. 226--249 in Darwin's Natural Selection]. This new construction of Wallace's ideas about diverging lineages and the significance of extinction was called by Darwin "Divergence of Character." While the elaboration of "Diver- gence of Character" occupied essentially all of the insert, it was introduced by mention of the relatively greater amount of variation in the species of larger genera as compared with smaller ones, followed by a rehearsal of the Gray letter's "principle of divergence." 74

Every statement found in the 1857 letter to Gray occurs not only in Natural Selection but also in the Origin. Furthermore, Darwin's additions to his discussion of divergence in the Origin (i.e., those not found in the letter to Gray) are not found in Wallace either; for example, theoretical reliance on domestic animals and artificial selection, naturalization of plants and animals, Milne-Edwards and the physiological division of labor, and tree diagrams and their relationship to Darwin's principles.

This last deserves attention. In the chapter on divergence in Darwin's Natural Selection he notes that "the complex action of these several principles, namely, natural selection, divergence & extinction, may be best, yet very imperfectly, illustrated by the following Diagram . . . . -75 He reiterated this position in the Origin, going on to add other principles such as the "principle of great benefit being derived from divergence of character . . . [which, in combination with the principles of natural selection and of extinction] . . . will generally lead to the most different or divergent variations . . . being preserved and accumulated by

74. Ibid.,p. 250. 75. Darwin, NaturalSelection, p. 238.


natural selection." 76 The interactions were illustrated by diagrams similar to those in Natural Selection. 77

Darwin's principles provided a framework for the development of his theories that is not to be found in Wallace's papers. And yet, in spite of all the differences, Darwin continued to the end of his life to believe that their theories were the same, noting in his "Autobiography" that his earlier "plans were overthrown, for early in the summer of 1858 Mr. Wallace, who was then in the Malay archilepago, sent me an essay, and this essay contained exactly the same theory as mine. ''78 Although their theories may have had equal force, they were certainly not the same in detail.

Schweber interprets the situation thusly, with recourse neither to Wallace's paper nor to the Darwin commentary on Wallace's 1855 paper, but to Darwin's notes of 1837 and 1857, and the letter to Gray in September 1857:

The principle was once again amplified when Darwin worked on the "Geographical Distribution" [sic] chapter of Natural Selection in the spring of 1858. It was evidently then that it occurred to him to amalgamate the visualization of the tree-of- life diagrams of the early B notebooks with the dynamics of the principle of divergence. The famous diagram on page 116 of the Origin (which also appears in Natural Selection) represents the process of speciation both in space and in time. It is the high point of the Origin and dramatically illustrates the origin of species. 79

It seems all creation with him. It is difficult to gauge the tenor of Darwin's argument here. Kohn interprets it to reflect a "disquali- fying religious tone, ''8° but Darwin himself repeatedly used the word "creation" in his own writings. What other words were available? Darwin suggested the word "generation," but it is important to keep in mind that he had long since worked out his theory of evolution by means of natural selection, and that, at this particular time, Wallace was still three years away from working out his own theory. In actual fact, Wallace used several terms interchangeably -- for example, "created," '~formed," "came into

76. Darwin, Origin (1859), pp. 116--117. 77. Ibid.,pp. 116--126. 78. Charles Darwin, "Autobiography," in Life and Letters of Charles Darwin,

ed. Francis Darwin, 3 vols. (London: Murray, 1888), I, 84--85. 79. Schweber, "Darwin and the Political Economists," pp. 213--214. 80. Kohn, "Origin of Principle," p. 1106.


existence" -- while Darwin continued to use "creation" as a convenient kind of shorthand. Thus, it is hardly surprising that in 1855 Wallace should also make use of this common term, "creation." In the words of the British anatomist Richard Owen: "Always, also, it may be well to bear in mind that by the word 'creation' the zoologist means 'a process he knows not what.' "81

There was nothing esoteric or arcane in the choice of topics discussed in books of the period. A number of them made a regular appearance: affinities, analogies, classification, centers of creation, origin of species, extinction, geographical distribution, rudimentary organs -- but, although frequently used, these and other words lacked clear definition, adding to the complexities of interpretation. 82 The same topics were discussed, whatever their precise meaning, by Lamarck, Lyell, and Chambers, for instance, because they were commonly thought to be important.

To add another twist, Darwin and Wallace came upon the theory of natural selection by different routes. From the beginning there was a fundamental distinction between their theories, as well as a number of others of lesser significance. Even when the same words were used, they were often imbued with different meanings. Darwin based his argument on domesticated animals and plants, while Wallace based his on wild animals and plants living in a state of nature.

It is all creation, but why does his law hold good; he puts the facts in striking point of view. What, indeed, did Wallace's law encompass? In Wallace's opinion, his law

agrees with, explains, and illustrates all the facts connected with the following branches of the subject: - - 1st, The system of natural affinities. 2nd, The distribution of animals and plants in space. 3rd, The same in time, including all the phenomena of representative groups, and those which Professor Forbes supposed to manifest polarity. 4th, The phenomena of rudimentary organs. 83

Darwin's question, "why does his law hold good?" is noteworthy in several respects. There were always to be differences between himself and Wallace, but at this time the gulf between them was particularly wide. Darwin already had theories of evolution and

81. Darwin, Origin (1872), p. 20. 82. See, for example, Brooks, Before the Origin, pp. 210--212, 224. 83. Wallace, "On the Law," p. 186.

Darwin and Divergence: The Wallace Comlection 25

natural selection to work with, and Wallace did not. Wallace was describing the situation as he saw it; Darwin could go beyond this to raise questions. And, in asking why Wallace's law held good, he was essentially asking the question, "why divergence?"

"It is evidently possible," Wallace had written, "that two or three distinct species may have had a common antitype, and that each of these may again have become the antitypes from which other closely allied species were created. ''84 Tracing these backwards revealed straight or parallel lines in cases involving a succession of single species. "But if two or more species have been independently formed on the plan of a common antitype, then the series of affinities will be compound, and can only be represented by a forked or many-branched line. ''85 (It was at this point that Darwin lightly sketched his diagram of a tree on his personal copy of Wallace's 1855 paper.)

Whether the lines were parallel or divergent, species could be traced back to common antitypes. Wallace gave no reason for "the species being so numerous and the modifications of form and structure so varied" other than to suggest that they had arisen

probably from the immense number of species which have served as antitypes for the existing species, and thus produced a complicated branching of the lines of affinity, as intricate as the twigs of a gnarled oak or the vascular system of the human body. Again, if we consider that we have only fragments of this vast system, the stem and main branches being represented by extinct species of which we have no knowledge, while a vast mass of limbs and boughs and minute twigs and scattered leaves is what we have to place in order, [so as] to determine the true position each originally occupied with regard to the others, the whole difficulty of the true Natural System of classification becomes apparent to us . . . .

. . . The extinction of species, however, offers but little difficulty, and the modus operandi has been well illustrated by Sir C. Lyell in his admirable Principles . . . . To discover how the extinct species have from time to time been replaced by new ones down to the very latest geological period, is the most difficult, and at the same time the most interesting problem in the natural history of the earth. The present inquiry, which seeks to eliminate [sic] from known facts a law which has deter-

84. Ibid. 85. Ibid.


mined, to a certain degree, what species could and did appear at a given epoch, may, it is hoped, be considered as one step in the right direction towards a complete solution of it. 86

Much effort has been expended in trying to determine when Darwin worked out his explanation of divergence -- so far, inclusively. The theory offered here suggests that this occurred sometime between September 1855 (the publication date of Wallace's paper) and September 1857 (when Darwin wrote to Asa Gray) and is derived, at least in part, from Darwin's question to himself on why Wallace's law held good. Darwin himself was not too forthright in this regard. "It is to me really laughable," he wrote to George Bentham on June 19, 1863, "when I think of the years which elapsed before I saw what I believe to be the explanation of some parts of the case; I believe it was fifteen years after I began before I saw the meaning and cause of the divergence of the descendants of any one pair. ''87 As already mentioned, de Beer calculated from this information that the year in question was 1852, but this was for the discovery, not of the fact of divergence, but of a causal explanation for it. 88 Brown points out that this could have taken place in any year between 1852 and 1857, as the beginning date is not clearly specified. 89 But whatever the date, the letter to Bentham suggests a continuum in Darwin's thinking, not a brand new discovery.

Darwin later added other details in his "Autobiography":

But at that time I overlooked one problem of great importance; and it is astonishing to me, except on the principle of Columbus and his egg, how I could have overlooked it and its solution. This problem is the tendency in organic beings descended from the same stock to diverge in character as they become modified. That they have diverged greatly is obvious from the manner in which species of all kinds can be classed under genera, genera under families, families under sub-orders, and so forth; and I can remember the very spot in the road, whilst in my carriage, when to my joy the solution occurred to me; and this was long after I had come to Down. The solution, as I believe, is that

86. Ibid., pp. 187,190 (emphasis added). 87. Charles Darwin, The Life and Letters of Charles Darwin, Including an

Autobiographical Chapter, ed. Francis Darwin, 3 vols. (London: Murray, 1888), III, 26.

88. De Beer, Charles Darwin, p. 140. 89. Browne, "Botanical Arithmetic," p. 82n63.


modified offspring of all dominant and increasing forms tend to become adapted to many and highly diversified places in the economy of nature. 9°

Schweber makes the following observations:

Given the importance that Darwin attached to the principle of divergence, it is interesting that although he could remember the very spot in the road where the solution occurred to him, he could not pinpoint more accurately the date of his insight. It would seem that there were sufficient milestones in his life - - e.g., the completion of his first volume on the cirripedes -- for Darwin not to have to append "I believe" to his dating. Also, in view of the importance of the principle, it is odd that Darwin does not indicate the context in which he arrived at his principle. 91

If its discovery was in any way connected with Wallace, Darwin would have been loath to say so, and this might account for the otherwise curious absence of detail.

But what turned Darwin's attention to a principle of divergence in the first place? It seems possible that he might not have worked one out if he had not been challenged by Wallace's 1855 paper - - not, however, because he was unaware of divergence, but because he would have thought it unnecessary, divergence falling under his broader theory, natural selection. In January 1855 he wrote that "On Theory of Descent, a divergence is implied & I think diversity of structure supporting more life is thus implied." 92

Francis Darwin shared this opinion:

In reading the Sketch of 1844, I have found it difficult to recognise, as a flaw in the Essay, the absence of any definite statement on the principle of divergence. Descent with modification implies divergence, and we become so habituated to a belief in descent, and therefore in divergence, that we do not notice the absence of proof that divergence is in itself an advantage. As shown in the Autobiography, my father in 1876 found it hardly credible that he should have overlooked the problem and its solution. 93

90. Darwin, "Autobiography," p. 84. 91. Schweber, "Darwin and the Political Economists," pp. 216--217. 92. Ospovat, Darwin's Theory, p. 180. 93. Darwin, "Autobiography," pp. 15-- 16.


In the original table of contents for his "big species book," Darwin indicated that two pages were reserved for "Extinction & Divergence plays part," folios 26 and 27. Folio 27 is missing, 94 but a substitute has been discovered among Darwin 's notes by Ospovat :

Every single organism may be said to try its u tmost to increase (geometrically), therefore there is strongest possible power tending to make each site to suppor t as much life as possible - - H o w to measure life Chemical act ion - - H o w can most life be suppor ted? By diversity ((utilizing different food - - like division o f labour in organs)) - - Explain chemicity [?] facts - - isl d - - coral islets - - square yard of turf - - Better still grasses - - Wheats - - Heaths - - Clovers at Lands End. Results - - habit ult imately structure - - Ch. 6.95

A further hint comes f rom some words that can be deciphered, a l though they are crossed out, at the top of folio 28: "a small and a very large scale. The principle of divergence, I believe, plays an impor tant par t in the affinities or classification of all organic beings." 96

M a n y of the points just ment ioned can be t raced f rom these scraps to the letter to Gray, and thence to Natural Selection and the Origin. For instance, the phrase "a small and a very large scale," found at the top of folio 28, is carr ied over to Natural Selection in expanded form:

We see on a great scale, the same general law in the natural distr ibution fo organic beings; if we look to an extremely small a r e a . . . Heaths [etc.]; 97

and is fur ther refined in the Origin:

The truth of the principle, that the greatest amount of life can

94. Darwin, Natural Selection, pp. 213, 572; Brooks, Before the Origin, pp. 232--234.

95. Ospovat, Darwin's Theory, p. 184. 96. Brooks, Before the Origin, p. 234; Ospovat, Darwin's Theory, p. ! 84. 97. Darwin, Natural Selection, p. 229. Kohn ("Origin of Principle," p. 1107)

properly takes Brackman to task for not understanding the relationships con- necting the letter to Gray to the Origin. Brooks, who earlier did not mention the letter to Gray at all (see n. 47 above), in 1984 said that he thought it "reasonable to assume that most of the text of folio 27 was essentially similar to the treatment of the 'principle of divergence' in the letter to Gray" (Before the Origin, p. 235).


be supported by great diversification of structure, is seen under many natural circumstances. In an extremely small area, especially if freely open to immigration, and where the contest between individual and individual must be severe, we always find great diversity in its inhabitants. For instance, I found that a piece of tuff, three feet by four in size, which had been exposed for many years to exactly the same conditions, supported twenty species of plants, and these belonged to eighteen genera and to eight orders, which shows how much these plants differed from each other. So it is with the plants and insects on small and uniform islets; and so in small ponds of fresh water. Farmers find that they can raise most food by a rotation of plants belonging to the most different orders: nature follows what may be called a simultaneous rotation. Most of the animals and plants which live close round any small piece of ground, could live on it (supposing it not to be in any way peculiar in its nature), and may be said to be striving to the utmost to live there; but, it is seen, that where they come into the closest competition with each other, the advantages of diversification of structure, with the accompanying differences of habit and constitution, determine that the inhabitants, which thus jostle each other most closely, shall, as a general rule, belong to what we call different genera and orders. 98

Darwin's chapter 6 on "Nat: Selection" was originally finished on March 31, 1857. Counting from Darwin's first notebook in 1837, there are five stages of his work to be consulted, culminat- ing, of course, in the Origin. Second are the note found by Ospovat and folios 27 and 28, written before March 31, 1857; third, the letter to Gray, September 5, 1857; fourth, the forty-page insert on divergence added to Natural Selection, late spring, 1858; fifth, the discussion on divergence in the Origin, 1859.

In the letter to Gray, Darwin remarked that "it follows, I think, from the foregoing facts, that the varying offspring of each species will try (only few will succeed) to seize on as many and as diverse places in the economy of nature as possible"99 _ _ demonstrably a benefit or advantage, and an answer to Darwin's original question, "but why?"

Ospovat describes this as follows:

In Natural Selection and the Origin of Species Darwin retained

98. Darwin, Origin (1859), p. 114. 99. Darwin, Life and Letters, II, 125 ( # 2136).


the division of labor as a leading theme in his exposition of divergence. But in his account of the process, he shifted the emphasis from the group to the individual or variety within the group. He argued that it follows from the principle that the most diverse can best succeed, that among the varying offspring of a species those that are most different from the others and from the parent form have the best chance of surviving. In this way the advantage of diversity, a group characteristic of the larger group, was translated into the advantage of being different, which is a characteristic of individuals or varieties and hence selectable. 1°°

After writing the letter to Gray on September 5, 1857, Darwin did not return to the subject of divergence until the following spring (except briefly in a letter to Gray on November 29 [see below, n. 153]). Perhaps it was then that he discarded the statement on a principle of divergence in t. 27 (now missing), finding it outmoded by the advances in his thinking over the past year. Its place was taken by an insert of over forty pages, written or corrected between April 14 and June 12, 1858.1°1 Darwin was ready to proceed with the development of his new theory. "[B]ut our principle of divergence explains," he wrote, "how the most diversified varieties will generally have decided advantages over the less diversified & intermediate varieties." New principles were now added, namely, those of natural selection and of extinction. 1°2 Summarizing, Darwin explained:

Taking a more modest glance into futurity, we may predict that the dominant genera, now abounding with common & widely difused species, will tend to be still more dominant for at least some considerable lapse of time, & will give rise to new groups of species, always diverging in character, & seizing on the places occupied by the less favoured forms, whether or not their near blood relations, supplanting them & causing their extermination. The great & flourishing genera both of plants & animals, which now play so important a part in nature, thus viewed become doubly interesting, for they include the ances- tors of future conquering races. In the great scheme of nature, to that which has much, much will be given.

100. Ospovat, Darwin's Theory, p. 181. 101. Darwin, NaturalSelection, p. 213. 102. Ibid., pp. 242, 238.


Finally, then, in regard to our principle of Divergence, which regulates the natural Selection of variations, & causes the Extinction of intermediate & less favoured forms, I believe it to be all important as explaining why the average difference between two species of the same genus, the parents of which by our theory once existed as mere varieties, is greater than the average difference between two such varieties. It bears on, & I think explains, the classification or natural affinities during all times of all organic beings, which seeming to diverge from common stems are yet grouped like families within the same tribes . . . .

The relation of all past & present beings may be loosely compared with the growth of a few gigantic trees . . . . 103

Darwin developed his theory further in the Origin, adding several new principles, among them the following: that the greatest amount of life can be supported by great diversification of structure; of great benefit; of inheritance; of preservation, "called, for the sake of brevity, Natural Selection."1°4 "We may," he said, "I think,"

assume that the modified descendants of any one species will succeed by so much the better as they become more diversified in structure, and are thus enabled to encroach on places occupied by other beings. Now let us see how this principle of great benefit being derived from divergence of character, combined with the principles of natural selection and of extinction, will tend to act . . . .

• . . Only those variations which are in some way profitable will be preserved or naturally selected• And here the importance of the principle of benefit being derived from divergence of character comes in; for this will generally lead to the most different or divergent variations . . . being preserved and accumulated by natural selection . . . .

. . . Natural selection, as has just been remarked, leads to divergence of character and to much extinction of the less improved and intermediate forms of life. On these principles, I believe, the nature of the affinities of all organic beings may be

103. Ibid., pp. 248--249. 104. Darwin, Origin (1859),pp. 114, 116,127.


explained. It is a truly wonderful fact - - the wonder of which we are apt to overlook from familiarity - - that all animals and all plants throughout all time and space should be related to each other in group subordinate to group, in the manner which we everywhere behold. 1°5

Again Darwin mentioned the tree analogy, remarking that "the affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth." The tree diagram that Darwin drew in the margin of his copy of Wallace's paper dated back to his first notebook of 1837. More complicated diagrams are to be found both in Natural Selection and, in somewhat revised form, in the Origin, the latter also including the much simpler sketch already referred to. 1°6

Of the several points raised by Darwin in his summary remarks about Wallace's paper, Kohn mentions only the following: "uses my simile of tree," "creation," and "nothing very new." "There was no principle of divergence in the 1855 paper," Kohn says, "nothing to be influenced by, nothing to steal." 107 But he forgets the difference in vantage points, for Darwin already had his theories of evolution and natural selection, while Wallace had neither.

It is precisely here that Wallace could exert his greatest influence on Darwin's thinking, for Darwin could recognize that the problem of divergence posed in Wallace's paper required a solution, and he asked, as noted, "why does his law hold good?" Clearly, Wallace was not the only influence on Darwin's thinking, but he was one of the few Darwin competitors in the field of biology. Indeed, Wallace's 1858 paper, judging from its title, "On the Tendency of Varieties to Depart Indefinitely from the Original Type," might itself be considered as one long effort to arrive at a satisfactory answer, especially as Wallace himself had by this time arrived at theories of both evolution and natural selection.

To recapitulate, Wallace's law holds good because it explains the branching patterns of the tree of life with its parallel and

105. Ibid.,pp. 116, 117, 128. 106. Darwin, Origin (1859), p. 129, and between pp. 116 and 117; idem,

Natural Selection, pp. 236--237. Not discussed in the present paper are Wallace's arguments "against our supposed geological perfect knowledge" or the explanation of rudimentary organs, positions on which Darwin and Wallace both agreed.

107. Kohn, "Origin of Principle," p. 1106 (emphasis added).


diverging lines by demonstrating that divergence is not random. It is related both to "what species could and did appear at a given epoch" (Wallace), and to the fact that divergence was itself a benefit because it allowed more life to exist in "the same spot" (Darwin). 1°8 At the same time, the gradually increasing complexity of Darwin's principle of divergence, from the note of January 1855 to the letter to Gray, and through to Natural Selection and the Origin, argues for the recency of these developments. How closely these steps are related to Darwin's first efforts in 1837 can be debated. As Oldroyd has remarked, "later investigators of Darwin's work on divergence have been inclined to see significant differences between the fully-fledged principle and the early idea of branching." 109 His early efforts marked a beginning at least, but it is the developments from 1855 on that are the most important here. In any case, Darwin's familiarity with the subject does date back to 1837.

Ill. 1855--1857

6. One other principle, which may be called the principle of divergence, plays, I believe, an important part in the origin of species. The same spot will support more life if occupied by very diverse forms: we see this in the many generic forms in a square yard of turf (I have counted twenty species belonging to eighteen genera), or in the plants and insects, on any little uniform islet, belonging to almost as many genera and families as to species. We can understand this with the higher animals, whose habits we best understand. We know that it has been experimentally shown that a plot of land will yield a greater weight, if cropped with several species of grasses, than with two or three species. Now every single organic being, by propagat- ing rapidly, may be said to be striving its utmost to increase in numbers. So it will be with the offspring of any species after it has broken into varieties, or sub-species, or true species. And it follows, I think, from the foregoing facts, that the varying offspring of each species will try (only few will succeed) to seize on as many and as diverse places in the economy of nature as possible. Each new variety or species when formed will generally take the place of, and so exterminate its less well-fitted parent. This, I believe, to be the origin of the classification or

108. Wallace, "On the Law," p. 190; Darwin, Life and Letters, II, 124 (#2136).

109. Oldroyd, "Darwin's Theory," p. 371n257.


arrangement of all organic beings at all times. These always s e e m to branch and sub-branch like a tree from a common trunk; the flourishing twigs destroying the less vigorous -- the dead and lost branches rudely representing extinct genera and families.

Charles Darwin to Asa Gray, September 5, 1857 H0

In a letter to his cousin William Darwin Fox on March 27, 1855 (more than a year before Lyell warned Darwin that he should begin to write for publication), Darwin summarized his thoughts as follows:

I forget whether I ever told you what the object of my present work is, - - it is to view all facts that I can master (eheu, eheu, how ignorant I find I am) in Natural History (as on geographical distribution, palaeontology, classification, hybridism, domestic animals and plants, &. &. &.) to see how far they favour or are opposed to the notion that wild species are mutable or immut- able: I mean with my utmost power to give all arguments and facts on both sides. I have a n u m b e r of people helping me in every way, and giving me most valuable assistance; but I often doubt whether the subject will not quite overpower me. 11t

Eight months later, on November 28, the eminent British geologist Charles Lyell opened the first of seven scientific journals on the species question. The very first entry was an outline of Wallace's recently published paper (dated September 1 8 5 5 ) " O n the Law Which Has Regulated the Introduction of New Species," which Lyell had read for the first time only a day or two earlier. 112 "This seems to have struck [him] so forcibly," comments Leonard Wilson, "that he entered some notes on it in the first of" his series of notebooks. 113 Lyell's immediate reaction to Wallace's law was that it

goes far towards Lamarck's doctrine [of change].

It may be that the old combination of Geological condit, s still continues so nearly that as it never did before or since, yet some

110. Darwin, Life and Letters, II, 124-- 125 ( # 2316). 111. Ibid., II, 49 ( # 1656). 112. Lyell, Scientific Journals, pp. 3--8, 65--66. 113. Ibid., p. xli.


new condit, s required a modific." beyond the variability of the old species so a new allied one is required. 114

Thomas Huxley was another who was "forcibly" struck by Wallace's 1855 paper. "Wallace was," as he said,

far away in the Malay Archipelago; but, apart f rom his direct share in the promulgation of the theory of natural selection, no enumerat ion of the influences at work, at the t ime I am speak- ing of, would be complete without the mention of his powerful essay . . . . 1~5

In April 1856 the Lyells visited the Darwins at Down, f rom the thirteenth to the sixteenth of that month. It was on this occasion, apparently, that Darwin first discussed his theory of natural selection with Lyell, and Lyell first discussed Wallace's paper with him, and again, Lyell's reaction was immediate:

The reason why Mr. Wallace['s] introduction of species, most allied to those immediately preceding in Time, or that new species was in each geol. t period akin to species of the period immediately antecedent, seems explained by the Natural Selec- tion Theory. 116

This is the paper that Darwin dismissed, according to Browne, as "merely another creationist tract, ''117 although four years later his opinion as expressed in the Origin differed little f rom that expressed by Lyell, who always thought highly of it. Two years later, when Wallace's 1858 paper reached Darwin, Darwin recalled Lyell's words: "Some year or so ago you recommended me to read a paper by Wallace in the 'Annals, ' which had interested

114. Ibid., p. 66. Lyell also noted (p. 6): "Of innumerable ways in which Omnipotence might fit a new species to all the present and future condit. S of its existence, there may be one which is preferable to all others, and if so this will cause the new species to be in all probability allied to preexisting and extinct or with many coexisting species of the same genus."

115. Thomas Henry Huxley, "On the Reception of the Origin of Species," in Darwin, Life and Letters, II, 185.

116. Lyell, Scientific Journals, xliii--xlvii, 55. Did Darwin read Wallace's paper before or after this meeting with Lyell? The comments on his personal copy of it are not dated.

117. Browne, Secular Ark, p. 173. Kohn makes a similar claim in his "Origin of Principle," p. 1106.


you . . . . Your words have come true with a vengeance - - that I should be forestalled." 118

One wonders whether Darwin and Lyell discussed the subject again in the interval. Whether or no, Lyell took the matter seriously enough to urge Darwin to begin writing for publication - - and for priority. 119 "With respect to your suggestion of a sketch of my views," Darwin wrote Lyell on May 3, 1856, "I hardly know what to think . . . . I rather hate the idea of writing for priority." On the nineth he wrote to Hooker , saying that "I believe I should sneer at any one else doing this, and my only comfort is, that I truly never dreamed of it, till Lyell suggested it . . . . " Again, on the eleventh to Hooker , that "it yet strikes me as quite unphilosophical to publish results without the full details which have led to such results." 120

In spite of his reluctance, however, on May 14, 1856, Darwin "began by Lyell's advice writing Species Sketch. ''121 But, "by October 1856, Darwin had come to the conclusion that he could not publish a short sketch of his theory, but must begin to write a full account as well as he could from his accumulated information," as Wilson states it322 On October 3 he wrote again to Fox:

I r emember you protested against Lyell's advice of writing a sketch of my species doctrines. Well, when I began I found it such unsatisfactory work that I have desisted, and am now drawing up my work as perfect as my materials of nineteen years ' collecting suffice, but do not intend to stop to perfect any line of investigation beyond current work. Thus far and no farther I shall follow Lyell's urgent advice)23

This is what became Darwin's "big species book," which he entitled Natural Selection.

It was also about this time, according to Ospovat , that, with the integration of the principle of divergence into the theory of natural selection, Darwin's theories reached a new level of refinement.

118. Darwin, Life and Letters, 1I, 116 ( # 2285). 119. Lyell proposed publication in a still-unpublished letter dated May 1,

1856 (# 1862): "I wish you would publish some small fragment of your data 1,] pigeons if you please & so out with the theory & let it take date -- & be cited, & be understood."

120. Darwin, Life and Letters, II, 67--70 (# 1866, # 1870, # 1874). 121. Darwin, "Darwin's Journal," p. 14. 122. Lyell, Scientific Journals, p. xlix. 123. Darwin, Life and Letters, II, 84 ( # 1967).


This occurred "in about September 1856," Ospovat writes. 124 It is worth recalling that Lyell saw a connection between Wallace's law and Darwin's natural selection some months previously, in April 1856.

Darwin could not have known it, but at almost the same moment - - October 10, 1856 - - Wallace, then in the Far East, was initiating a correspondence with Darwin. 125 He was at that time in the Dutch town of Macassar on the island of Celebes, two years into the extensive travels that took him from one end of the Malay Archipelago to the other.

Meanwhile, Darwin worked steadily away on his new plan, finishing the second chapter "& before part of Geograph Distr." on October 13; the third, on December 16; the fourth, on "Var: Nature," on January 26, 1857; the fifth, "Struggle for Existence," on March 3; and the sixth, on "Nat: Selection," on March 31. The seventh and eighth chapters were completed on September 29, followed by a chapter on "Hybridism" on December 29.126

Within weeks of finishing the chapter on natural selection on March 31, 1857, Darwin received his first letter from Wallace. "I am much obliged," Darwin answered on May 1, '~for your letter of Oct. 10th from Celebes, received a few days ago. ''127 Brackman, basing his claim on usual travel times, maintains that Darwin must have received this letter written on October 10 much earlier, "most likely around New Year's Day," and that he delayed several months in answering it 128 _ _ but surely this is any correspondent 's prerogative. More importantly, the contents of Wallace's letter, now missing, can in part be determined from Darwin's answer:

In a laborious undertaking, sympathy is a valuable and real encouragement. By your letter and even still more by your paper in the Annals, a year or more ago, I can plainly see that we have thought much alike and to a certain extent have come to similar conclusions. In regard to the paper in the Annals, I agree to the truth of almost every word of your paper; and I daresay that you will agree with me that it is very rare to find oneself agreeing pretty closely with any theoretical paper. 129

124. Ospovat, Darwin's Theory, p. 193. 125. Marchant, Wallace, Letters, p. 107. 126. Darwin, "Darwin's Journal," p. 14. 127. Marchant, Wallace, Letters, p. 107 (# 2086). 128. Brackman, Delicate Arrangement, pp. 44--45; Kohn disputes Brackman

on this point ("Origin of Principle," p. 1107). 129. Marchant, Wallace, Letters, p. 107 (emphasis added); see n. 132 below.


Barely a year had passed since Lyell, spurred by Wallace's 1855 paper, had warned Darwin that he should begin writing for publication and priority. Lyell had had no difficulty then in understanding the relationship between the theories of Darwin and Wallace, the latter's law seeming, as he put it, to be."explained by the Natural Selection Theory. ' 'la° The letter f rom Wallace could only have served to heighten Darwin's anxiety and reinforce the need to follow Lyell's advice. If Lyell had grasped the meaning so quickly, what was to prevent Wallace f rom working this out on his own - - as indeed he did less than a year later, turning Lyell's premonit ion into hard reality.

In his letter of May 1, 1857, Darwin gave a hint to Wallace on the raison d '&re for his work:

This summer will make the twentieth year (!) since I opened my first note-book on the question how and in what way do species and varieties differ from each other [italics added; a short paper by Wallace on a similar topic was published in the Zoologist in January 1858 131[. I am now preparing my work for publication, but I find the subject so very large, that though I have written many chapters, I do not suppose I shall go to press for two years . . . .

• . . It is really impossible to explain my views in the compass of a letter as to causes and means of variation in a state of nature; but I have slowly adopted a distinct and tangible idea - - whether true or false others must judge)32

Browne takes this to have been a warning, apparently unnoticed by Wallace, and a resolve on Darwin's part that "he had no intention of disclosing more than was absolutely necessary; as far as he was concerned the topic was discreetly closed. ''133 This recalls Ger t rude Himmelfarb 's claim some years ago that Wallace was "duly warned off" by Darwin's answer in the letter of May 1, 1857.134 More likely, his agreement was a spur.

130. Lyell, Scientific Journals, pp. xlv, 55. 131. Alfred Russel Wallace, "Note on the Theory of Permanent and

Geographical Varieties," Zoologist, 16 (1858), 5887--88. 132. Marchant, Wallace, Letters, pp. 107--108. Darwin, Life and Letters, II,

95--96, gives a shortened version ( # 2086). 133. Browne, Secular Ark, p. 176. 134. Gertrude Himmelfarb, Darwin and the Darwinian Revolution (Garden

City, N.Y.: Anchor Books, 1962), p. 245.


Judging from this letter, Wallace's letter was far-ranging: the need to keep domestic and wild varieties distinct; the parentage of domestic animals; the sterility of hybrids; and the small effect of "climatic conditions. ''135 Whether Darwin referred to all the sub- jects brought up by Wallace cannot be known for certain, because Wallace's letter is missing (as are various other documents related to the early period of the Darwin-Wallace connection). 136 What can be said here is that Wallace showed himself to be a man of wide interests, befitting someone who at this time was planning a book of his own, as he mentioned to Darwin in his second letter (a scrap of which does remain). 137 At this point, it was based largely on Wallace's "long private argument with Lyell" over the latter's Principles of Geology.138

A few months later, on January 4, 1858, Wallace outlined his plans for a book in a letter to his old friend Bates:

To persons who have not thought much on the subject I fear my paper ]1855] on the succession of species will not appear so clear as it does to you. That paper is, of course, only the announcement of the theory, not its development. I have pre- pared the plan and written portions of an extensive work embracing the subject in all its bearings and endeavouring to prove what in the paper I have only indicated. It was the promulgation of Forbes's theory which led me to write and publish, for I was annoyed to see such an ideal absurdity put forth when such a simple hypothesis will explain all the facts.

I have been much gratified by a letter from Darwin [May 1, 1857], in which he says that he agrees with "almost every word" of my paper. He is now preparing for publication his great work on species and varieties, for which he has been collecting information twenty years. He may save me the trouble of writing the second part of my hypothesis by proving that there is no difference in nature between the origin of species and varieties ]italics added], or he may give me trouble by arriving at another conclusion, but at all events his facts will be given for me to work upon. Your collections and my own will furnish most valuable material to illustrate and prove the universal

135. Marchant, Wallace, Letters, p. 108. 136. Seen. 184below. 137. Beddall, "Wallace, Darwin," p. 282 and n. 60. For reproductions of

both sides of this scrap, see McKinney, Wallace, pp. 31, 127. 138. Beddall, "Wallace, Darwin," p. 271.


applicability of the hypothesis. The connect ion between the succession of affinities and the geographical distribution of a group, worked out species by species, has never yet been shown as we shall be able to show it. 139

To return to Darwin and to Wallace 's first letter, it seems possible that Darwin could have found this letter more than a little disquieting, especially if Wallace had included any reference to his own b o o k plans here. At the least, Darwin could not have been expecting to co r respond with the man whose recent paper had, upon Lyell 's urging, spurred his own effort.

On September 5, 1857, Darwin sent a letter to Asa Gray, enclosing an outline of his theories, including his principle of divergence, the sixth and last paragraph. 14° O n this score there is no doubt. What directly preceded this, however, has been a matter of dispute, subject to various interpretations.

Accord ing to Browne, "the ' trigger' which sparked off Darwin 's sudden formulat ion of the principle of divergence" was his recognition of an e r ror in the method of calculating his botanical arithmetic, pointed out to him by John L u b b o c k on July 13, 1857, a "relatively trivial event" in itself. This necessitated "two or three weeks' lost work," as Darwin ment ioned to H o o k e r the following day. TM

Ospova t shares Browne 's view on the heightened activity during the summer of 1857, at tr ibuted by both to Darwin 's problems with his botanical arithmetic, which is very likely true as far as it goes. ~42 But there was another possible source of anxiety (not

139. Marchant, Wallace, Letters, p. 54. The comments on Wallace's plans for his book are similar to the comment made to Darwin in Wallace's letter of September 27, 1857: "The mere statement & illustration of the theory in that paper [Wallace's 1855 paper] is of course but preliminary to an attempt at a detailed proof of it, the plans of which I have arranged, and in part written..." (see n. 137 above). Kohn says that Darwin had finished ten and a half chapters of his book, and that "Darwin had virtually completed the plan that Wallace was just contemplating" ("Origin of Principle," p. 1108). But Wallace was beyond this step, as his letter to Bates shows. The reference to Forbes is the following: Edward Forbes, "On the Manifestation of Polarity in the Distribution of Organized Beings in Time," Proc. Roy. Inst. London, 57 (October 1854), 332-- 337; see also Beddall, "Wallace, Darwin," p. 279, and McKinney, Wallace, pp. 44--46.

140. Darwin, Life and Letters, II, 120-- 126 ( # 2136). 141. Browne, "Botanical Arithmetic," pp. 77, 88; Darwin, Life and Letters,

II, 103--104 (~2123, #2124). 142. Ospovat, Darwin's Theory, p. 185.


mentioned by either, and antedating Lubbock's criticism by two months or so), and that was Wallace himself. If feeling pressed, Darwin may have felt the necessity of testing his theories out, and this could have led to the letter to Gray in September.

"In July 1857 [the seventh]," according to Kohn, "Gray had very directly asked Darwin to explain his views: 'It is just such sort of people as I that you have to satisfy and convince, and I am a very good subject for you to operate on, as I have no prejudice nor prepossessions in favour of any theory at all.'-143 The context, however, suggests a much narrower focus -- that is, extinction and its relation to genera and their ranges:

Of any given local species, it seems to me a priori, quite as likely (to say the least) that it never had a wide dominion, as that it had, and is on the road to extinction: - - that is of species of continents. As to islands, when you know their geological history, the presumption may be quite the other way, no doubt.

That is the way the question strikes an outsider like me -- a cautious and slow one, - - just at first view. If I had ever thought over the matter, and investigated it as you have, very likely I should think quite differently. But it is just such sort of people as I that you have to satisfy and convince, and I am a very good subject for you to operate on, as I have no prejudice nor prepossessions in favour of any theory at all.

I never yet saw any good reason for concluding that the several species of a genus must ever have had a common or continuous area. Convince me of that, or show me any good grounds for it (beyond the mere fact that it is generally the case), - - i.e. show me why it ought to be so, and I think you would carry me a good way with you -- as I dare say you will, when I understand it. 144

Clearly, Gray was referring here to the concerns of the moment. In fact, and contrary to Kohn's assertion, Darwin made the

request himself, perhaps on the strength of Gray's letter of July 7 (see above), in his answering letter to Gray dated July 20, 1857) 45

143. Kohn, "Origin of Principle," p. 1107. 144. Gray to Darwin, July 1857 ( # 2120, unpublished). 145. Darwin, Life and Letters, II, 78--80; A. Hunter Dupree, Asa Gray,

1810--1888 (Cambridge: Harvard University Press, 1959), pp. 244--245; BeddaU, "Wallace, Darwin," p. 291. This letter was originally placed in the year


These letters have not previously been associated, the first because it is still unpublished, the second because it has been misplaced in the year 1856, when it should be in the year 1857, which clearly alters the context and the interpretation of it. Indeed, the interpretation of all the correspondence of the summer of 1857 is thrown off course if the letter of July 20 is thought to belong in 1856.

"I should like to tell you (and I do not think I have) . . . ," written on July 20, was followed on September 5 by, "As you seem interested in the subject, and as it is an immense advantage to me to write to you and to hear, ever so briefly, what you think, I will enclose (copied, so as to save you trouble in reading) the briefest abstract of my notions on the means by which Nature makes her species" 146 _ _ marking Darwin as the initiator of this exchange in the summer of 1857.

Returning to Darwin's letter of July 20:

What you say about extinction, in regard to small genera and local disjunction, being hypothetical seems very just. Something direct, however, could be advanced on this head from fossil shells; but hypothetical such notions must remain [confirming the subject matter of the preceding letter; omitted in Life and Letters]. It is not a little egotistical, but I should like to tell you (and I do not think I have) how I view my work. Nineteen years (!) ago it occurred to me that whilst otherwise employed on Nat. Hist., I might perhaps do good if I noted any sort of facts bearing on the question of the origin of species, and this I have since been doing. Either species have been independently created, or they have descended from other species, like varieties from one species . . . . But as an honest man, I must tell you that I have come to the heterodox conclusion, that there are no such things as independently created species - - that species are only strongly defined varieties. I know that this will make you despise me . . . .

I must say one word more in justification (for I feel sure that your tendency will be to despise me and my crotchets), that all

1856; it was Dupree who placed it correctly in 1857 ( # 2125). Both Braekman (Delicate Arrangement, pp. 53--54) and Brooks (Before the Origin, p. 261) accept the original dating, 1856. This letter is not mentioned at all by Browne, Gruber, Ospovat, or Schweber.

146. Darwin, Life and Letters, II, 78, 121 ( # 2125, # 2136).


my notions about how species change are derived from long- continued study of the works of (and converse with) agricul- turists and horticulturists; and I believe I see my way pretty clearly on the means used by nature to change her species and adapt them to the wondrous and exquisitely beautiful conting- encies to which every living being is exposed. 147

On August 22, 1857, Darwin wrote to Hooker:

If it all hold good it is very important for me; for it explains, as I think, all classification, i.e., the quasi-branching and sub-branching of forms, as if from one root, big genera increasing and splitting up, etc. as you will perceive. But then comes in, also what I call a principle of divergence, which think I can explain, but which is too long, and perhaps you would not care to hear.148

Darwin seems not to have pursued this tack. Instead, on September 5 he wrote the letter to Gray, enclosing an outline of his theories, which included his principle of divergence. Briefly, his six points covered the following topics: (1) Selection by man; (2) Slight changes, unlimited time; (3) Natural Selection, natural population increase; (4) Country undergoing changes; extermination of parent forms; some better adapted; (5) "Extreme imper- fections of our geological records" (a point also emphasized by Wallace); (6) Principle of divergence. 149

The personal note that accompanied the outline is of course not a part of the official record of the Linnean Society meeting, but there can be little doubt that this letter to Gray followed Darwin's letter of July 20. In Gray's August answering letter, of which a fragment remains, he had apparently taken exception to Darwin's fear that Gray would despise him for his views, and he signed the

147. Ibid., pp. 78--80. 148. Browne, "Botanical Arithmetic," pp. 82--83; Schweber, "Darwin and

the Political Economists," pp. 214--215; Darwin, More Letters, I, 99 (#2134, emphasis added).

149. Darwin, Life and Letters, II, 120--125 (the six points appear on pp. 122--125) (# 2136). "The date is given as October in the 'Linnean Journal,'" Francis Darwin noted: "The extracts were printed from a duplicate undated copy in my father's possession, on which he had written, 'This was sent to Asa Gray 8 or 9 months ago, I think October 1857'" (Life and Letters, II, 120n). The original is in the possession of the Gray Herbarium. Darwin wrote to Gray on July 4, 1858, requesting the correct date ( # 2302, unpublished).


letter "with the highest regard." ~5o Darwin answered in his letter of September 5 that

I should have been a strange mortal, seeing how much I owe to your quite extraordinary kindness, if in saying this [that Gray "would utterly despise" him] I had meant to attribute the least bad feeling to you . . . .

I thank you most truly for the kind spirit of your last letter. I agree to every word in it, and I think I go as far as almost any one in seeing the grave difficulties against my doctrine. 151

The letter includes an odd, often-remarked request:

In regard to my Abstract, you must take immensely on trust, each paragraph occupying one or two chapters in my book. You will, perhaps, think it paltry in me, when I ask you not to mention my doctrine; the reason is, if any one, like the author of the "Vestiges," were to hear of them, he might easily work them in, and then I should have to quote from a work perhaps despised by naturalists, and this would greatly injure any chance of my views being received by those alone whose opinions I value.152

Given the attendant circumstances, Wallace seems as likely a candidate as Chambers to have given occasion for these precau- tionary words.

What was Darwin's purpose in sending his outline to Gray in the first place? He clearly feared premature disclosure ( " . . . I ask you not to mention my doctrine"), but he also wanted to test his ideas out. Gray would make a better sounding board than Hooker for the very reasons that Gray himself had mentioned in his letter of July 7 (see above). Hooker , on the other hand, was already privy to many of Darwin's theories. Whether Darwin was also trying to preserve his own priority in regard to his theories cannot be determined (he was certainly within his rights to try), although in fact this was the outcome some nine months later.

Darwin was apparently satisfied with Gray's response (missing), writing him in answer on November 29. This letter, not published

150. Gray to Darwin, Aug. 1857 ( ¢~ 2129, unpublished). 151. Darwin, Life and Letters, II, 120--121 (# 2136). 152. Ibid.,p. 122.


until 1903, has also been misdated and placed in the year 1859 instead of 1857. In it Darwin expressed his appreciation of Gray's criticisms:

This shall be such an extraordinary note as you have never received from me, for it shall not contain one single question or request. I thank you for your impression on my views. Every criticism from a good man is of value to me. What you hint at generally is very, very true: that my work will be grievously hypothetical, and large parts by no means worthy of being called induction, my commonest error being probably induction from too few facts. I had not thought of your objection of my using the term "natural selection" as agent.

Omitted from the published letter was the following:

This rule, as I must consider it [,] of the large genera varying most, I look at as most important for my work and I believe it to be the foundation of the matrix in which all beings are grouped in classifications, together with what I rather [?] call my principle of divergence, i.e., the tending to the preservation from extinction of the most different members of each group. ~53

IV. 1858--1859

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, when they become wild, 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

153. Darwin, More Letters, I, 126--127 (#2176); redated by Dupree, Asa Gray, p. 459n24; Beddall, "Wallace, Darwin," pp. 311, 320. The second paragraph quoted here, on Darwin's principle of divergence, was omitted when the letter was first published.

46 B ARBARAG. BEDDALL

in past ages, and all the extraordinary modifications of form, instinct, and habits which they exhibit.

Alfred Russel Wallace, "On the Tendency of Varieties to Depart

Indefinitely from the Original Type," 1858154

On December 22, 1857, Darwin answered the second letter that he had received from Wallace (written on September 27, again from Macassar during his second stay on Celebes, from July to November 18 5 7).155 Among other things, Darwin remarked:

You say that you have been somewhat surprised at no notice having been taken of your [1855] paper in the Annals . I cannot say that I am; for so very few naturalists care for anything beyond the mere description of species. But you must not suppose that your paper has not been attended to: two very good men, Sir C. Lyell, and Mr. E. Blyth at Calcutta, specially called my attention to it. 156

Lyell's reaction has already been mentioned. Blyth, the curator of the museum of the Asiatic Society of Bengal in Calcutta and one of Darwin's regular correspondents, wrote to him on Decem- ber 8, 1855, asking him:

What think you of Wallace's paper in the Ann . N. Hist.? Good! Upon the w h o l e ! . . .

What do you think of the paper in question? Has it at all unsettled your ideas regarding the persistence of species, - - not perhaps so much from novelty of argument, as by the lucid collation of facts & phenomena.157

154. Wallace, "On the Tendency," here quoted from Alfred Russel Wallace, Natural Selection and Tropical Nature: Essays on Descriptive and Theoretical Biology (London: Macmillan, 1891), p. 33.

155. Alfred Russel Wallace, The Malay Archipelago: The Land of the Orang- utan and the Bird of Paradise: A Narrative of Travel, with Studies of Man and Nature (London: Macmillan, 1869; reprint, New York: Dover, 1962), p. 175.

156. Darwin, Life and Letters, II, 108--110 (#2192) (a third of Darwin's letter is omitted here); Marchant, Wallace, Letters, p. 109.

157. Barbara G. Beddall, "Wallace, Darwin, and Edward Blyth: Further Notes on the Development of Evolution Theory," J. Hist. Biol., 5 (1972), 155, 157 (# 1792). On November 19, 1856, Wallace's friend Henry Walter Bates, still in South America, wrote approvingly about the 1855 paper: "The theory I quite


In the meantime, Darwin continued to work on his "big species book," completing the planned chapters consecutively. In April 1858 he finished revising his botanical calculations, and on the fourteenth of that month he began "Discussion on large genera & small & on Divergence & correcting Ch. 6. (Moor Park) finished June 12th." He was at Moor Park, a hydropathic establishment, from April 22 to May 6. On May 6 he sent his MS on large and small genera to Hooker , arranging on the sixteenth to talk this over with him. 158

If Darwin had planned on using the letter to Gray as the basis for an expansion of his ideas on a principle of divergence, there is nothing surprising about his having done so after finishing other chapters for which he had already done much work. In fact, ideas first found in the notes quoted by Ospovat were carried through to the Gray letter, Natural Selection, and the Origin.

Nevertheless, various suggestions have been put forward to account for Darwin's return, in the spring of 1858, to the subject of divergence, mentioned in the original outline of his chapter on natural selection and first finished on March 31, 1857. For Brooks, it was the conjectural arrival of Wallace's 1858 manuscript in late May; for Browne and Ospovat, the finishing of the recalculations of his botanical arithmetic. 159 There were others, of course, who deemed that no further explanation was necessary. R. C. Stauffer refers to the work done in the spring of 1858 as "additions and revisions," but the latter word gives the impression that major corrections were involved. 16° It was, rather, Darwin's first attempt at a detailed working out of his principle of divergence, amounting to a forty-plus-page insert, which replaced the two-page outline of the preceding year.

The year 1858 was a momentous one in the history of evolutionary theory. In late February Wallace was on the Moluccan island of Ternate, where he wrote out his paper "On the Tendency of Varieties to Depart Indefinitely from the Original type. ''161

assent to, and, you know, was conceived by me also, but I profess that I could not have propounded it with so much force and completeness" (Marchant, Wallace, Letters, pp. 52--53).

158. Darwin, "Darwin's Journal," p. 14; idem, Life and Letters, II, 107 ( # 2269, and # 2274, unpublished).

159. Brooks, Before the Origin, p. 250; Browne, Secular Ark, p. 216; Ospovat, Darwin's Theory, pp. 188,207.

160. Darwin, NaturalSelection, p. 213. 161. McKinney (Wallace, pp. 131--138) claims that Wallace was on Gilolo,

not Ternate; Brackman (Delicate Arrangement, p. 198n) dismisses such a "deception" as "ludicrous."


Having by now received at least one answering letter f rom Darwin, he seems to have decided to make use of this opening by sending his new paper to Darwin, with the request that he "foreward it" to Lyell) 62

The date on which Darwin received this paper has been a subject of contention in recent years. Brackman, Brooks, and McKinney have all asserted that it was earlier than the commonly accepted date of June 18, allowing time for Darwin to incorporate some of Wallace's ideas into his own work. 163 In fact, this is a pointless argument, at least as far as the joint papers are con- cemed, for within weeks Wallace's paper was read before the Linnean Society. Not only that, Darwin's work of the preceding months was not a part of what became the joint papers, for Darwin's claims were based on his letter to Gray of September 1857.

Furthermore, on many key points Wallace and Darwin strongly disagreed. Indeed, some of their beliefs were then considered to be incompatible. Darwin, for instance, relied heavily on arguments based on domestic animals and plants and artificial selection. "As has always been my practice," Darwin noted, "let us seek light on this head f rom our domestic productions. ''164 Wallace, on the other hand, questioned many of the deductions that followed from this line of reasoning - - the relative stability or instability of domestic versus wild varieties, for example - - and he based his own theories entirely on wild species living in a state of nature. 165 Such differences, as well as differences of definition, make comparisons difficult and "stealing" even more so.

Another important difference arose f rom Darwin's conviction that "the same spot will support more life if occupied by very diverse forms," which gave an ecological cast to his argument on divergence. 166 Wallace, on the other hand, based his argument on the appearance of varieties better equipped to withstand environmental stresses of one kind or another, leading to "progression and

162. Darwin, Life and Letters, II, 116--117 ( # 2285). 163. Brackman, Delicate Arrangement, pp. 16--19, 348; Brooks, Before the

Origin, pp. 252--257; McKinney, Wallace, pp. 138--141. See also Schweber, "Darwin and the Political Economists," p. 213n50, for some details on Brooks. Schweber was misinterpreted by Brackman (see above, Section I).

164. Darwin, Origin (1859),pp. 111--112. 165. Wallace, "On the Tendency," pp. 22--23. 166. Darwin, Life and Letters, II, 124 (#2136) -- an integral component of

Darwin's principle of divergence, later accepted by Wallace (see quotation from his Darwinism, n. 1 above); Darwin, Origin (1859), p. 114, a slightly altered form.


continued divergence" (italics Wallace's). 167 Extinction for Darwin was brought about by the extermination by a variety of its "less well-fitted parent." For Wallace, extinction was brought about by environmental stresses, the superior variety remaining. 168

But such differences in detail apparently gave way before the functional equivalence of the theories of the two men. This idea is lost, however, when comparisons are made based on the unspoken assumption that Darwin's exposition approaches some sort of ideal or "perfect" state, from which any deviations or omissions are considered to be faults. This Whiggish interpretation is exem- plified by Bowler when he says that

the two men were certainly arguing along different lines: Wallace did not deal with selection of individual differences, postulated only an episodic selection of varieties, and had no concept of divergence through ecological specialization. One can only conclude that it was quite reasonable for Darwin's friends to give Wallace's paper a subordinate position in the joint presentation to the Linnean Society. 169

But what would it have availed Darwin to have taken any ideas from Wallace's new paper? After its arrival (perhaps even on that disputed date of June 18), Darwin chose to have his position demonstrated by the letter to Gray of the preceding September, not by any more recent statements. In a letter to Lyell on June 25, Darwin wrote: "About a year ago I sent a short sketch, of which I have a copy, of my views (owing to correspondence on several points) to Asa Gray, so that I could most truly say and prove that I take nothing from Wallace." 170

There was certainly no impropriety here, whether one considers Darwin "secretive" or not. Nor was there any in Darwin's having written out this statement in the first place, whether his motive was to protect his ideas (implied by the request to Gray "not to mention my doctrine" in order to keep it from people like the author of the Vestiges), ~.71 or to test it against a knowledgeable person like Gray, or for any other reason. What impinged on Wallace's reputation was what followed in regard to publication.

167. Wallace, "On the Tendency," pp. 28--29. 168. Darwin, Life and Letters, II, 125 (¢~2136); Wallace, "On the Tend-

ency," pp. 28--29. 169. Bowler, "Wallace and Darwinism," p. 278; see also Mayr, n. 208 below. 170. Darwin, Life and Letters, II, 117 ( # 2294). 171. Beddall, "Wallace, Darwin," p. 292.


Here Darwin was the winner and Wallace the loser in regard to priority in what now became, in game-theory terms, a zero-sum game. Up to this point it had been a non-zero-sum game in which Darwin's productivity was stimulated by Wallace, but with no loss to the latter. The converse is also true: witness Wallace's attempted solution to the Gakipagos islands puzzle posed by Darwin. 172

But a loss on one level does not necessarily mean loss at all levels. Even if Darwin was awarded overall priority, for example, Wallace did not lose priority on his own individual contributions where the details differed from those proposed by Darwin. That this is a complex matter can be seen from Darwin's claim that his theories and Wallace's were the "same," a position he held for the rest of his life. And from this point of view, priority of presentation, whatever the details, was indeed the plum.

The worst possible outcome, and a real scandal, would have been the concealment of the Wallace manuscript, or even its destruction. But Wallace's paper was published in short order, certainly establishing his rights in regard to the details therein, while any liberties taken by Darwin, if there were any, would not see the light of day until the publication of the Origin in November 1859.

From the time when Lyell had first urged Darwin to write for publication, Darwin had been troubled by priority, but there was never any doubt that he understood the role of publication. "I rather hate the idea of writing for priority," he had written to Lyell on May 3, 1856, "yet I certainly should be vexed if any one were to publish my doctrines before me. ''173 That day had now arrived, as Lyell and Darwin had feared it might, the challenge arising from a not unexpected quarter, Alfred Russel Wallace. Darwin's first reaction (keeping here to the June 18 date) was to write to Lyell that "he does not say he wishes me to publish, but I shall, of course, at once write and offer to send to any journal. So all my originality, whatever it may amount to, will be smashed . . . . ,, 174

This was mentioned in the introductory statement accompanying the joint papers: "So highly did Mr. Darwin appreciate the value of the views therein set forth, that he proposed, in a letter

172. John von Neumann and Oskar Morgenstern, Theory of Games and Economic Behavior (Princeton, N.J.: Princeton University Press, 1947), pp. 34n2, 46--47. See also n. 211 below.

173. Darwin, Life and Letters, II, 68 ( # 1866). 174. lbid.,p. 116(#2285) .

Darwin and Divergence: The Wallace Connec t ion 51

to Sir Charles Lyell, to obtain Mr. Wallace 's consent to allow the Essay to be published as soon as possible." A t the least, this would have al lowed sufficient time to work out a more satisfactory answer to the problem. Instead, the letter of transmittal claimed that "both authors having now unreservedly placed their papers in our hands, we think it would best p rom o t e the interests of science that a selection f rom them should be laid before the Linnean society. ''175 If indeed both m e n had been consulted, the mat ter would rest there, but this is no t the case.

Wi th the recent publicat ion of the Calendar of the Correspon- dence of Charles Darwin, the s tory takes a new t u r n ) TM Firstly, all the dates used in the above analysis of what happened in the summer of 1857 are conf i rmed there. Secondly, and at a key point - - that is, Darwin 's letter to Lyell on June 25, 1858 - - certain of Francis Darwin 's textual omissions, hi therto unnot iced, are now seen to be significant. Apparent ly , this letter was no t received by Lyell until June 29. The italicized sentences below were omit ted by Francis Darwin and do not appear in the published Life and Letters:

I am very sorry to t rouble you, busy as you are, in so merely personal an affair; but if you will give me a deliberate opinion, you will do me as great a service as ever man did, for I have entire conf idence in your judgment and honour . I should not have sent off your letter [to Wallace?] without further reflexion, for I am at present quite upset, but write now to get subject for time out of mind. But I must confess that it never did occur to me, as it might, that Wallace could have made any use of your letter.

There is nothing in Wallace 's sketch which is not written out

175. Charles Darwin, Evolution and Natural Selection: An Anthology of the Writings of Charles Darwin, ed. Bert James Loewenberg (Boston: Beacon Press, 1959), pp. 138, 137.

176. The Calendar, an extraordinarily bountiful source of information, nevertheless contains a few shortcomings. Not indicated are either previous erroneous datings or previous textual omissions, nor are there references to letters now missing but known from other correspondence to have existed. There are also occasional oversights, in particular in regard to Wallace's September 27, 1857, letter to Darwin (# 2145). This letter is represented by a scrap only, one side of which answers Darwin's question on jaguars, while the other concerns Wallace's plans for his own book; both sides of this scrap are reproduced in McKinney, Wallace, pp. 31,127.


much fuller in my sketch, copied out in 1844, and read by Hooke r some dozen years ago. About a year ago I sent a short sketch, of which I have a copy, of my views (owing to correspondence on several points) to Asa Gray, so that I could most truly say and prove that I take nothing f rom Wallace. I should be extremely [itahcs in original] glad now [italics in original] to publish a sketch of general views in about a dozen pages or so; but I cannot persuade myself that I can do so honourably. Wallace says nothing about publication, and I enclose his letter. But as I had not intended to publish any sketch, can I do so honourably, because Wallace has sent me an outline of his doctrine? I would far rather burn my whole book, than that he or any other man should think that I had behaved in a paltry spirit. Do you not think his having sent me this sketch ties my hands? I do not in least believe that that [sic] he originated his views from anything which I wrote to him. If I could honourably publish, I would state that I was induced now to publish a sketch (and I should be very glad to be permitted to say, to follow your advice long ago given) f rom Wallace having sent me an outline of my general conclusions [a similar statement occurs in the introduction to the Origin]. We differ only, that I was led to my views f rom what artificial selection has done for domestic animals. I would send Wallace a copy of my letter to Asa Gray, to show him that I had not stolen his doctrine. But I cannot tell whether to publish now would not be base and paltry. This was my first impression, and I should have certainly acted on it had it not been for your letter [missing]. 177

The first omission suggests that, in his now-missing letter to Darwin in answer to Darwin's letter of June 18, Lyell himself was concerned about what he proposed to say to Wallace, as Darwin apparently was also. This letter appears not to have been sent. The second omission is more surprising and puts the shoe on the other foot. Far f rom substantiating claims such as those made by Brackman and Brooks, it clearly shows that the opposite was the case: that the question was whether Wallace could have gleaned anything f rom Darwin's letters to him, not what Darwin might have taken f rom Wallace. Together, these omissions also demon- strate that Francis Darwin, the editor of his father's papers, was not above omitting key references to Wallace. "No doubt," to use

177. Darwin, Life and Letters, II, 117--118 (# 2294). The complete text is at the American Philosophical Society.


Kohn's phrase, he also "colored the judgment of history," along with Hooker and Lyell.

These circumstances may explain Lyell's haste in setting up the Linnean Society meeting. It might have been an attempt to salvage something before something else occurred.

On June 26, Darwin wrote to Lyell again:

Wallace might say, "You did not intend publishing an abstract of your views till you received my communication. Is it fair to take advantage of my having freely, though unasked, communi- cated to you my ideas, and thus prevent me forestalling you?" The advantage which I should take being that I am induced to publish from privately knowing that Wallace is in the field. It seems hard on me that I should be thus compelled to lose my priority of many years' standing, but I cannot feel at all sure that this alters the justice of the case. First impressions are generally right, and I at first thought it would be dishonourable in me now to publish. 178

These sentiments were countered by Darwin's friends in a solution to his dilemma that was worked out by Lyell, with Hooker's assistance. What became known as the "joint papers" were read at a meeting of the Linnean Society on July 1, a forum only accidentally available because of the death of a council member; the next regularly scheduled meeting would not take place until the following November. 179 On the night of June 29 Darwin wrote to Hooker that he was sending Wallace's manuscript as well as his own sketch of 1844 ("never," he appended in a note in the published version, "intended for publication, and therefore was not written with care"), in which divergence was not mentioned, and the letter to Gray of September 5, 1857 (of which he wrote similarly to Gray, that it was "never written, & not fit for such purposes"), 18° in which it was:

I have just read your letter [missing], and see you want the papers at once. I am quite prostrated, and can do nothing, but I send Wallace, and the abstract of my letter to Asa Gray, which gives most imperfectly only the means of change, and does not

178. Ibid., pp. 118--119 ( # 2295). 179. Beddall, "Wallace, Darwin," pp. 299--318; the letter to Gray

( # 2136) was erroneously dated October 1857 on this occasion. 180. Darwin, Evolution and Natural Selection, p. 138; Darwin to Gray, July

4, 1858 (#2302).


touch on reasons for believing that species do change. I dare say all is too late. I hardly care about it. But you are too generous to sacrifice so much time and kindness. It is most generous, most kind. I send my sketch of 1844 solely that you may see by your own handwriting that you did read it. I really cannot bear to look at it. Do not waste much time. It is miserable in me to care at all about priority.IS1

The letter transmitting these documents to the Linnean Society was dated June 30, which gave little time for a thoughtful appraisal of their contents. According to Lyell and Hooker, Darwin had given them

permission to make what use we thought proper of his memoir, &; 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. 182

At a celebration of this event in 1908, Hooker, then ninety-one (Lyell had died at seventy-eight in 1875), remarked:

It cannot fail to be noticed that all these inter-communications between Mr. Darwin, Sir Charles Lyell, and myself were con- ducted by correspondence, no two of us having met in the interval between June the 18th and July the 1st, when I met Lyell at the evening meeting of the Linnean Society; and no fourth individual had any cognisance of our proceedings. 183

It was Hooker who, on this occasion, first called attention to the fact that material was missing:

181. Darwin, Life and Letters, II, 119--120 ( # 2297, # 2298). 182. Darwin, Evolution andNaturalSelection, pp. 138--139 (#2299). 183. Beddall, "Wallace, Darwin," p. 301. This particular paragraph was

omitted from the account given in Marchant (Wallace, Letters, p. 98), but see Linnean Society of London, The Darwin-Wallace Celebration HeM on 1st July, 1908, by the Linnean Society of London (London: The Society, 1908), p. 15.

Darwin and Divergence: The Wallace Connection 5 5

It must also be noticed that for the detailed history given above there is no documentary evidence beyond what Francis Darwin has produced in the "Life and Letters." There are no letters from Lyell relating to it, not even answers to Mr. Darwin's of the 18th, 25th, and 26th of June; and Sir Leonard Lyell has at my request very kindly but vainly searched his uncle's correspondence for any relating to this subject beyond the two above mentioned. There are none of my letters to either Lyell or Darwin, nor other evidence of their having existed beyond the latter's acknowledgment of the receipt of some of them; and, most surprising of all, Mr. Wallace's letter and its enclosure have disappeared. 184

To return to the Linnean Society meeting in 1858, if Darwin had ever hoped to preserve his priority by way of the letter to Gray, Lyell, as his principal sponsor on this issue, could now ensure it. Indeed, this was not the first time that Lye[i, clearly quick and impatient by nature, had played this role. In a letter to Hooker on May 11, 1856, Darwin mentioned a previous occasion on which, "(again from Lyell's urgent advice), I published a preliminary sketch of the Coral Theory, and this did neither good nor harm," a point that apparently bothered Hooker, who feared that such early publication "might supersede and take away all novelty and value from any future larger Book." 185

At the evening meeting, as Hooker noted afterwards, "Lyell's approval, and perhaps in a small way mine, as his lieutenant in the affair, rather overawed the Fellows, who would otherwise have flown out against the doctrine. ''186 Lyell was by far the senior member of the trio, sixty-one to Hooker's forty-one and Darwin's forty-nine. Hooker later recalled a more active role for himself, 187 but at the time this role seems to have been Lyell's.

184. Marchant, Wallace, Letters, pp. 98--99. Kohn ("Origin of Principle," p. 1107) ignores not only Hooker's statement of the case, but also the listing of letters, missing or otherwise, in Beddall, "Wallace, Darwin," pp. 309--311, 318-- 323. Brackman's Delicate Arrangement can be considered as a failed attempt to account for the missing material mentioned by Hooker in 1908. Kohn answers this problem by comparing ratios of missing/nonmissing material for others of Darwin's correspondents, concluding that the survival ratios were all roughly similar. But this presupposes an egalitarianism among papers, whether missing or not, that simply does not exist. Some papers are surely more equal than others, and their disappearance cannot be so lightly dismissed.

185. Darwin, Life and Letters, II, 71 ( # 1870). 186. Ibid.,p. 126. 187. Marchant, Wallace, Letters, pp. 97--99.


The possibility, first suggested to him by Lyell, that Wallace had somehow been able to copy from him, continued to plague Darwin, and in a still-unpublished letter of July 4, he wrote to Asa Gray about it:

It is very unlikely, but if by any chance you have my notions of "Natural Selection" and would see whether it or my letter bear any date, I should be very much obliged. Why I ask this, is as follows. Mr. Wallace, who is now exploring New Guinea, has sent me an abstract of the same theory, most curiously coincident even in expressions. And he could well have heard a word of my views.

But how, and from whom? He had already removed himself as a possible source, leaving only Lyell, Hooker, and Gray as other possibilities. As for the latter, he had, after all, specifically re- quested that Gray not "mention my doctrine" for fear that "any one, like the author of the 'Ves t iges ' . . . might easily work them in." Hooker and Lyell could be counted out, but Gray, he seemed to say, could not. Darwin's letter continues:

He directed me to forward it to Lyell. Lyell, who is acquainted with my notions, consulted with Hooker, (who read a dozen years ago a long sketch of mine written in 1844) urged me with much kindness, not to let myself to be quite forestalled & to allow them to publish with Wallace's paper an abstract of mine; & as the only very brief thing which I had written out was a copy of my letter to you. I sent it and I believe it has just been read, (though never written, & not fit for such purposes) before the Linnean Society; and this is the reason, why I should be glad of the date. But do not hunt for it, as I am sure it was written in September, October or November of last year. I have troubled you with a long story on this head; do pray forgive me & believe me . . . . 188

(But, although he denied it, Darwin himself might have been at fault by lending encouragement to Wallace. "I agree to the truth of almost every word of your paper [in the Annals]," Darwin had written in his first letter to Wallace. In the days before copying machines, Darwin would not have had a copy at hand to consult later.)

188. # 2302, not yet published (emphasis added).


Gray's answer to this letter, written on July 27, is missing. In Darwin's reply to it, of August 11, he remarks that "it is a real and great pleasure to me to write to you about my notions." 189 There was no further discussion about how Wallace might have arrived at his own theories.

On July 13, Darwin wrote to Hooker about a letter to Wallace:

Your letter to Wallace seems to me perfect, quite clear and most courteous. I do not think it could possibly be improved, and I have to-day forwarded it with a letter of my own. I always thought it very possible that I might be forestalled, but I fancied that I had a grand enough soul not to care; but I have found myself mistaken and punished; I had, however, quite resigned myself, and had written half a letter to Wallace to give up all priority to him, and should certainly not have changed had it not been for Lyell's and your quite extraordinary kindness. I assure you I feel it, and shall not forget it. I am m o r e than satisfied at what took place at the Linnean Society. I had thought that your letter and mine to Asa Gray were to be only an appendix to Wallace's paper) 9°

The fact is, however, that neither Darwin nor Wallace was well served by Lyell's haste. It does not redound to Darwin's credit that his priority claim appeared to require special help, nor were Darwin's qualms properly addressed. Indeed, his express wishes were subverted, while Wallace's rights were neglected. To have been scrupulously fair, Lyell, as an interested party (if not the prime mover) and a self-selected referee, could (or should) have turned the decision over to someone else. His precipitous action in thus presenting unpublished works, bypassing the judgment of referees who might reject them as "not strictly scientific, ''~91 has left some questions open, and a lingering doubt about the fairness remains.

This has spawned some remarkable conclusions, for, other than by fiat, there is now no final way to resolve the problem. Thus, in spite of the passage of 125 years, the matter still lacks a definitive answer. At one extreme is the stand taken by Eiseley:

When Wallace sent his theory to Darwin and there occurred

189. Darwin, Life and Letters, II, 135 (# 2321). 190. Ibid., p. 128 ( # 2306). 191. Ibid.,p. 127 (#2303).

5 8 BARBARA G. BEDDALL

that mutual nobility of behavior so justly celebrated in the annals of science -- a tolerance and recognition of their two claims which led to the reading of their preliminary papers jointly before the Linnean Society in 1 8 5 8 . . )92

-- when, in fact, Wallace was halfway round the world and knew nothing whatever about the reading of the papers until the following October. "It was printed," Wallace wrote later, "without my knowledge, and of course without any correction of proofs. I should, of course, like this fact to be stated." 193

At another extreme are the claims made by Lyell and Hooker in "the interests of science generally" in presenting the papers, "taken in the order of their dates," before the society) 94 As noted above, once the decision had been made, Darwin readily agreed with the verdict. Wallace too was pleased, and he wrote both to Hooker on October 6 and to his mother on the same date, expressing his pleasure in his recognition by "these eminent men. ''~95 But whether approval by the protagonists should have any bearing on scientific approval is another question.

Darwin had been further pleased that Hooker was planning to write to Wallace: "I certainly should much like this, as it would quite exonerate me." 196 And on July 18 Darwin wrote to Lyell that he did not "think that Wallace can think my conduct unfair in allowing you and Hooker to do whatever you thought fair. ''197 Darwin himself must have had some lingering doubts.

But that Wallace's work was indeed of value can be seen from the fact that Darwin "began Abstract of Species book" -- which became the Origin - - between July 20 and August 12, only weeks after the reading of the joint papers. 198 In the introduction to the Origin a year later, Darwin acknowledged Wallace's role:

My work is now nearly finished; but as it will take me two or

192. Loren Eiseley, Darwin's Century." Evolution and the Men Who Dis- covered It (Garden City, N.Y,: Doubleday, 196 l), p. 292; see n. 48 above.

193. A, B. Meyer, "How Was Wallace Led to the Discovery of Natural Selection?" Nature, 52 (August 29, 1895), 415; based on a letter from Wallace, dated November 22, 1869. See also Beddall, "Wallace, Darwin," p. 313.

194. Darwin, Evolution andNaturalSelection, p. 138. 195. Marchant, Wallace, Letters, p. 57. The letter to Hooker is in the

possession of Quentin Keynes ( # 2337). 196. Darwin, Life and Letters, II, 127. 197. Ibid.,p. 129(#2309) . 198. Darwin, "Darwin's Journal," p. 14.


three more years to complete it, and as my health is far from strong, I have been urged to publish this Abstract. I have more especially been induced to do this, as Mr. Wallace, who is now studying the natural history of the Malay archipelago, has arrived at almost exactly the same general conclusions that I have on the origin of species. Last year he sent to me a memoir on this subject, with a request that I would forward it to Sir Charles Lyell, who sent it to the Linnean Society, and it is published in the third volume of the Journal of that Society. Sir C. Lyell and Dr. Hooker , who both knew of my work -- the latter having read my sketch of 1844 -- honoured me by thinking it advisable to publish, with Mr. Wallace's excellent memoir, some brief extracts from my manuscripts. 199

Many years later, Darwin wrote in his autobiography that he had been forestalled in only one important point,

which my vanity has always made me regret, namely, the explanation by means of the Glacial period of the presence of the same species of plants and of some few animals on distant mountain summits and in the arctic regions. This view pleased me so much that I wrote it out in extenso, and I believe that it was read by Hooker some years before E. Forbes published his celebrated memoir on the subject. In the very few points in which we differed, I still think that I was in the right. I have never, of course, alluded in print to my having independently worked out this view. 2°°

At this remove, he also claimed, rather disingenuously, that he "cared very little whether men attributed most originality" to himself or Wallace, "and his essay no doubt aided in the reception of the theory. "2°1 He no longer seemed to feel that he had been forestalled by Wallace.

Some years ago, Charles Gillispie, in a paper on Lamarck and Darwin, remarked that "even though my argument is that Darwin's original contribution was the theory and not the evidence, I shall in the interests of economy perpetuate the injustice which makes Wallace's role in the history of science little more than an object

199. Darwin, Origin (1859), pp. 1--2. 200. Darwin, "Autobiography," p. 88. 201. Ibid.


lesson in the agonizing generosity of creative minds. ''2°2 When later questioned on this point by Brackman, however, he had altered his opinion, turning back, intentionally or no, to the form of patronage practiced by Lyell:

I believe that it now seems to me less of an injustice that the theory of natural selection should be associated primarily with Darwin than it did when I wrote the sentence that you quote to me . . . . I have come to have what may be a more mature appreciation of the intrinsic importance of institutional factors, and contextual factors, in making a scientific theory viable. Darwin was in an enormously better position than Wallace, personally, socially, financially, as to influence . . . . He was in a position to get a hearing . . . . 203

But how are scientific theories to be identified, and when? And by whom? Indeed, the argument as presented here sounds more political than scientific.

Other standards have recently been put forward. Kohn, for example, justifies "editorial manipulation" in the interests of Darwin's claims. There is no doubt, he says, that Lyell and Hooker "colored the judgment of history." In fact, he even goes so far as to agree with Brackman that the favoring of Darwin's priority over Wallace's was indeed "a delicate arrangement. "2°4 Nelson goes further yet in reporting that historians both agree with and approve of the use of "editorial manipulation" in the establishment of Darwin's priority 2°5 - - all of which suggests that finagling was required.

Does all this really mean what it appears to say, that the quality of scientific work is to be judged in accordance, not with its intrinsic merit, but with the position in life of the person who did the work? Who is to decide when such measures should be applied? And who is to be the judge? Interested persons, or disinterested persons? The self-appointed, who may have an interest in the outcome of the affair? Is such treatment to apply

202. Charles Coulston Gillispie, "Lamarck and Darwin in the History of Science," in Forerunners of Darwin: 1745--1859, ed. Bentley Glass, Owsei Temkin, and William L. Straus, Jr. (Baltimore: The Johns Hopkins Press, 1959; paperback reprint, 1968), p. 267.

203. Brackman, Delicate Arrangement, p. 345. 204. Kohn, "Origin of Principle," p. 1108. 205. Nelson, "Just before the Origin," p. 248; a position hardly flattering to

Darwin.


generally, or is it reserved for the Darwins of this world, however they might be determined?

"As with Newton in his controversy with Leibniz over the invention of the calculus," Rober t Merton has recently observed, "concern with establishing priority can lead to the use of dubious means to buttress valid claims." 206 But if such standards are not to become embedded in the literature, as it appears they might, they ought to be rejected now. Perhaps the fairest solution in the present case is to follow Mayr in his recognition of Wallace as a "co-discoverer" of the theory of natural selection. 2°7

Furthermore, Mayr, in his most recent book - - The Growth of Biological Thought - - asks the following questions:

The story about Darwin receiving Wallace's essay in June 1858 raises numerous questions. Was Darwin justified in writing to Lyell, "I never saw a more striking coincidence; if Wallace had my ms. sketch written out in 1842, he could not have made a better short extract! Even his terms now stand as heads of my chapters"? Was Wallace's theory really so nearly identical with Darwin's? H o w did Wallace assemble the pieces of his theory? Did he arrive at it by the same steps as Darwin, or by a process of convergence? 208

But whatever the answers to Mayr 's questions, these were not the questions being asked at the time. Darwin never gave up his conviction that Wallace's "essay contained exactly the same theory as mine," as he wrote many years later in his autobiography - - perhaps, as suggested above, because he continued to view the two as functional equivalents. 2°9 Lyell, too, was of this opinion, writing in 1863 that Wallace had "thought out, independently for himself, one of the most novel and important of Mr. Darwin's theories. ''2~°

206. Robert K. Merton, "Scientific Fraud and the Fight to Be First," Times Lit. SuppL, November 2, 1984, p. 1265.

207. Ernst Mayr, "The Triumph of Evolutionary Synthesis," Times Lit. Suppl., November 2, 1984, p. 1261.

208. Ernst Mayr, The Growth of Biological Thought." Diversity, Evolution, and Inheritance (Cambridge: Harvard University Press, 1982), p. 494; see also pp. 494--498 for his answers to these questions, and n. 169 above. Kohn ("Origin of Principle," p. 1106) says that "Wallace and Darwin derived two fundamentally different principles"; but if so, where does this leave the dispute over priority?

209. Darwin, "Autobiography," p. 85. 210. Charles Lyell, Antiquity of Man (London: Murray, 1863), pp. 408--

409.


This opinion was shared in 1858 by Darwin (see his letter to Lyell on June 18) and by Hooker and Lyell (see the letter of transmittal sent to the Linnean Society on June 30); and in 1859 by Darwin (see his letter to Wallace on April 6, as well as the introduction to the Origin and the text reference on p. 355).

Theories are rarely arrived at by identical routes, nor are they themselves absolutely identical, either, even when the concept is thought to be "in the air." Thus, "simultaneous" discoveries may resemble each other in varying degrees at different levels, with their similarities or differences depending on the definition of problems and solutions at the time. Priority is therefore an outcome of judgments made on whether the theories are considered to be the same. Publication serves as a useful standard and a way of imposing a certain amount of order.

In the narrow focus espoused both by the participants in the events leading up to and including the "joint papers," and by their successors, priority in this case has been treated as a "single event, ''2H a zero-sum game with winners and losers, an occasion when "editorial manipulation" and "delicate arrangements" could be invoked. But, as seen above, the matter is far more complex than this approach would indicate. It requires a broader perspec- tive in which the enormous contributions made by both Darwin and Wallace can be recognized. In game theory this would be a non-zero-sum game, where both Darwin and Wallace benefited from the work of the other, thus becoming codiscoverers of the theory of evolution by means of natural selection. If this interpretation of the events is rejected, the status of the matter reverts to a zero-sum game, which brings back with it not only its winners and losers, but also the problems of "editorial manipulation" and "delicate arrangements," as posed by Kohn and Nelson.

C O N C L U D I N G S T A T E M E N T

Wallace's contributions to biological thought tend to be overlooked or overly praised, neither of which produces a satisfactory assessment. Examples of the latter tendency are the recent exposi- tions by Brackman and Brooks; although both books contain much worthwhile material, both are flawed. At critical points their theories fail to measure up, Brackman's because of his misinter- pretations of events in the month of June 1858, and Brooks's

211. Dictionary of the History of Science, s.v. "priority disputes," which are "sometimes associated with an oversimple conception of discovery as a single event."


because of the tautological reasoning behind his datings of the events of May--June of that same year. This situation is more than counterbalanced by arguments that do not consider Wallace at all -- namely, those of Browne (1980), Ospovat, and Schweber. Nevertheless, the theories most compatible with those worked out in the present paper are those presented by Ospovat.

Some of the long-standing difficulties in regard to the matter of priority can be traced back to Lyell and his self-chosen role as dispenser of patronage at the time of the joint papers, which thus precluded other solutions to the problem. It is here, in what might be called Lyell's legacy, that a degree of unfairness can be detected, which has given rise to efforts to clarify the matter, especially as part of the documentation is missing. This, in turn, has led to the serious consideration of questionable standards such as "editorial manipulation" and "delicate arrangements," which, though applied to substantiate Darwin's priority, yet becloud his record.

Francis Darwin contributed to the confusion by omitting certain key statements -- in particular, Darwin's rejoinder to Lyell that he did not think that Wallace could have taken ideas from anything that Darwin had written to him. This sentence falls in the middle of a paragraph, which must mean that its removal was intended. Its absence, however, has allowed the opposite opinion to be put forward, as, for example, in the books by Brackman and Brooks.

Events of the year 1857 have been reinterpreted here, based on the following information regarding various letters: two 1857 letters have been misdated -- that of July 20 as 1856 (#2125) , and that of November 29 as 1859 (#2176) . Two others are still unpublished -- July 7 (# 2120) and August ( # 2129). And two others are missing -- Wallace's first letter to Darwin, received in late April 1857 and answered by Darwin on May 1, and a letter from Gray to Darwin written in the fall of 1857.

Wallace's influence on Darwin's thinking can be epitomized by Darwin's question about Wallace's law: "Why does his law hold good?" Also important in Darwin's commentary on Wallace's paper are his observation that Wallace "uses my simile of tree" -- a concept basic to a principle of divergence -- as well as his remarks on Wallace and creation, and on geographical distribution.

It seems possible that the letter from Wallace, which arrived in late April 1857, along with what was already evident in his 1855 paper, made Darwin take Lyell's warnings to heart. Indeed, if he did not take Wallace seriously, he should have, for within months Wallace had worked out the theory of natural selection for himself.


Darwin's September 5 letter to Gray could, and probably did, represent an ordering of his ideas in response to a felt challenge.

A fruitful way to characterize the relationship between Darwin and Wallace may be found ]n terms of game theory. Most scholars look upon the relationship as a zero-sum game, with a winner and a loser, the matter of priority being considered as a "single event." Another approach would be to look upon it as a non-zero-sum game with each man influencing the other. In this case, the productivity of one is stimulated by the contributions of the other, resulting in a net gain in knowledge overall, and both men become winners, or codiscoverers. This approach is possible if Wallace's contributions to the theory of evolution by means of natural selection are recognized.

Acknowledgments

For permission to quote from manuscript documents in their possession, I would like to express my appreciation to the following: to the American Philosophical Society for permission to quote from Darwin's letter to Lyell, June 25, 1858 (#2294); to the Syndics of Cambridge University Library, to quote from Lyell's letter to Darwin, May 1, 1856 (# 1862), Gray to Darwin, July 7, 1857 (#2120), Gray to Darwin, August 1857 (#2129), and Darwin's commentary on Wallace's 1855 paper; to the Gray Herbarium, to quote from Darwin's letters to Gray, November 29, 1857 (#2176), and July 4, 1858 (#2302); and to The Linnean Society of London, to quote from Wallace's "Notebook, 1855-- 1859," p. 50. I would like once again to thank my husband for his long-continued interest, support, and encouragement, not to mention an introduction to game theory many years ago.

CHRONOLOGY

(Numbers are those of the Calendar of the Correspondence of Charles Darwin; an asterisk indicates that the piece in question is missing; CD equals Charles Darwin, ARW equals Alfred Russel Wallace.)

1837 July CD opened his first notebook: "organized beings re-

present a tree, irregularly branched" (p. 43).

1839 CD's Journal and Remarks published.


May 18-- June 18

1842 CD: "wrote pencil sketch of my Species theory."

Feb .--July 1844

CD: "enlarged & improved pencil sketch in 35 pages" to 230 pages.

1845 CD's Journal of Researches published.

1852 De Beer and CD's causal explanation of divergence.

Sept. 9 1854

CD: "Began sorting notes for Species theory."

Jan.

March 27 Sept. 9

Nov. 26 Nov. 28

Dec. 8

1855 "On Theory of Descent, a divergence is implied" (see Ospovat, p. 180). CD to Fox (# 1656) explaining his plans. ARW's "Law" paper published in Annals. CD commentary on own copy of ARW's paper, date or dates unknown. Lyell read ARW's paper. Lyell began his first species notebook with notes on ARW's paper. Blyth in Calcutta to CD (# 1792) on ARW's paper.

April 13-- 16

April 16

May 1

May 3 May 9 May 11 May 14 Sept.

Oct. 3

1856 Lyells visiting at Down.

Lyell spoke of ARW's paper to CD, and CD to Lyell on his theory of natural selection. Lyell to CD (# 1862) urging CD to publish; letter is unpublished. CD to Lyell ( # 1866) on this suggestion. CD to Hooker (# 1870) on Lyell's suggestion. CD to Hooker (# 1874) on same. CD: "Began by Lyell's advice writing Species Sketch." Successful integration of divergence and natural selection, resulting in principle of divergence (Ospovat). CD to Fox (# 1967) on longer version, which became Natural Selection (published 1975); letter in 1903.


Oct. 10 Oct. 13

Nov. 19 Dec. 16

*ARW's first letter to CD, from Celebes. CD: "finished 2nd Chapt (& before part of Geograph Distr.)." Bates to ARW on latter's paper in Annals. CD: finished "3rd Chapt."

Jan. 26 March 3 March 31

Late April May 1

July 7

July 13-- 14

July 20

Aug. 22

Aug. ?

Aug. ? Sept. 5 Sept. 27

Sept. 29 Sept. 30--

Dec. 29 Autumn Nov. 29

Dec. 22

1857 CD: "Finished Ch. 4. Var: Nature." CD: "Fin d Ch. 5. Struggle for Existence." CD: "Finished Ch. 6 Nat: Selection." CD did not yet have a principle of divergence (Browne). CD received ARW's first letter, now missing. CD to ARW (#2086); nearly half omitted in LL; "I agree . . . " (see Marchant, Wallace, Letters, pp. 107-- 109). Gray to CD (#2120) on ranges of large and small genera; unpublished. CD to Lubbock (# 2123), and to Hooker (# 2124) on mathematical errors; CD unaware of need for a "principle" of divergence until mid-1857 (Browne). CD to Gray (#2125): "I should like to tell you"; redated from 1856. CD to Hooker (#2134) , mentioning principle of divergence; published 1903. Gray to CD (#2129); unpublished fragment (not missing). CD had "principle" of divergence (Browne). CD to Gray (# 2136), outlining his theories. ARW to CD (#2145) , answering #2086; scrap remains: black jaguars, plans for own work on other side. CD: "Finished Ch. 7 & 8." CD: "on Hybridism," ch. 9.

*Gray to CD, see # 2176. CD to Gray (# 2176): "I thank you for your impressions of my views"; omission on principle of divergence; published 1903; redated from 1859. CD to ARW ( # 2192), answering # 2145.

Jan. 4 Jan.

Feb.

1858 ARW to Bates on plans for his own book. ARW's "Note on the Theory of Permanent and Geog- raphical Varieties," published in Zoologist. *ARW's "On the Tendency of Varieties to Depart


March 9 April 1 4 -

June 12 May 6 May 16

May June 3

June June 8

June 12 June 14 June 17

June 18

June ? June 25 June 26

June ? June 29 June 29

June 30

July 1 July 4

July 5

Early July Early July July 13

July 13 July 13

Indefinitely from the Original Type," written in Ter- nate and sent with a letter to CD, both of which are missing. CD: "finished instinct chapter," ch. 10. CD: "Discussion on large genera & small & on Diver- gence & correcting Ch. 6." CD to Hooker ( # 2269) on large and small genera. CD to Hooker (# 2274) on large and small genera; unpublished. Brooks's arrival dates for ARW's paper: 18, 28--29. McKinney's date for London arrival of letter to Frederick Bates. Brackman's arrival dates for ARW's paper: 4, 8, 14. CD to Hooker ( # 2282); mentions principle of divergence; published 1903. CD: "finished June 12th & Bees cells." CD: "Pigeons (interrupted)." Linnean Society meeting canceled on the death of Robert Brown, botanist, on June 10. CD to Lyell (# 2285) on being forestalled by ARW's paper, just arrived. *Lyell to CD in answer to # 2285; see also # 2294. CD to Lyell ( # 2294): omissions by Francis Darwin. CD to Lyell (#2295) on CD's letter to Gray (#2136) . *Hooker to CD, see # 2297 and # 2298. CD to Hooker ( # 2297). CD to Hooker (#2298): "I send Wallace, and . . . Gray." Lyell and Hooker letter (# 2299) to Linnean Society transmitting the "joint papers." Linnean Society meeting, "joint papers" read. CD to Gray (# 2302): how did ARW come upon his ideas? Letter unpublished. CD to Hooker ( # 2303), mentioning exoneration, referees. *Hooker to ARW, see # 2306; lost by ARW. *Hooker to CD, see # 2307. Hooker to CD (#2307): "you overrate the extent of my opposition to your method"; in Huxley (not missing). *CD to ARW, see # 2306; lost by ARW. CD to Hooker (#2306): Hooker's letter to ARW "perfect."


July 18 July 20--

Aug. 12 July 27 Aug. 11

Oct. ? Oct. 6

Nov. 30

CD to Lyell ( # 2309): "more than satisfied." CD "began Abstract of Species book," i.e., the Origin.

*Gray to CD, see # 2302 and # 2321. CD to Gray (# 2321): "It is a real and great pleasure to me to write to you about my notions." *ARW to CD, see # 2405. ARW to Hooker on Linnean meeting; in possession of Quentin Keynes (# 2337, not missing). *ARW to CD, see # 2449.

Jan. 25 April 6

Nov. 24

1859 CD to ARW ( # 2405). CD to ARW ( # 2499): "your explanation of your law is the same as that which I offer," answering ARW of Nov. 30. Publication of the Origin.

Other missing Wallace letters include the following still known only from Darwin's answers: received by CD August 7, 1859; received March (?) 1860; February 16, 1860, received May 14, 1860.

Aug. 28 1908

Hooker spoke about the missing letters at a celebration to commemorate the 'Joint communication" of 1858.

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