Why Lamarck did not Discover the Principle of Natural Selection MAXINE SHEETS-JOHNSTONE Department of Dance Temple University Philadelphia, Pennsylvania 19122 In commenting on the work of Georges Buffon, Jean Baptiste Lamarck, and Charles Darwin, the historian J. S. Wilkie suggested that one of these scientists could be "observed in the act of not discovering the principle of natural selection. ''1 Although it was actually Buffon who came under the author's sleuthful gaze in this particular instance, his essay leaves no doubt that Lamarck too could have been caught in the act. Indeed he was, and has been since by other historians, though perhaps not so red-handedly. These examples illustrate the point: Lamarck's problem was not limited to a lack of evidence in support of the idea of organic change. He was also unable to provide a satis- factory mechanism to account for the facts of adaptation... Natural selection, the key to explaining adaptation that was discovered by Darwin and Wallace, never occurred to Lamarck. 2 Organic evolution implies that animate nature is in a constant state of change, but Lamarck was unwilling to push his concept to its logical extreme, a Instead of looking for such a factor [adaptation], I_amarck talked vaguely of "the cause which tends to the complication of organiza- tion," thus introducing an idea inconsistent with his materialistic outlook. 4 One more instance in which Lamarck made the wrong guess! s 1. J. S. Wilkie, "Buffon, Lamarck and Darwin: The Originality of Darwin's Theory of Evolution," in Darwin "s Biological Work, ed. Peter Robert Bell (Cam- bridge: Cambridge University Press, 1959), p. 278. 2. Richard W. Burkhardt, Jr,, The Spirit of System (Cambridge, Mass.: Harvard University Press, 1977), p. 212. 3. Frank N_ Egerton, "Studies of Animal Populations from Lamarck to Darwin," J. Hist. Biol., 1 (1968), 228. 4. John C. Greene, The Death of Adam (Ames: Iowa State University Press, 1959), p. 166. 5. Ernst Mayr, "Lamarck Revisited," J. Hist. Biol., 5 (1972), 72. Journal of the History of Biology, vol. 15, no. 3 (Fall 1982), pp. 443-465. 0022-5010/82/0153/0443 $02.30_ Copyright © 1982 by D. Reidel Publishing Co., Dordrecht, Holland, and Boston, U.S.A_ MAXINE SHEETS-JOHNSTONE Historians of science generally concur that Lamarck did not discover the principle of natural selection, but they appear at times to believe that he let the principle slip through his fingers. The impression is clearly, "If only Lamarck had .... then he would have... " The belief that he muffed it, so to speak, is apparent in a variety of contexts, but perhaps nowhere is it more clearly illustrated than in the following passage. The author is considering Lamarck's rightful, but alas, short- sighted, emphasis upon the environment with respect to adaptation: Here was an opportunity for Lamarck, the experienced zoologist, to test his theory. For instance, when he cites the sloth (Bradypus) as an animal which, owing to its arboreal locomotion, leaf-eating habits, and existence in the hot tropics, has acquired all sorts of adaptations, including extreme slowness of movement, he should have asked himself whether other equally tropical and arboreal mammals with similar food habits, such as the leaf-eating monkeys, had become slothlike. He would have found out that they acquired entirely different adaptations and have remained quick and lively. 6 The purpose of the present paper is, first, to question whether the historical view of Lamarck implicit in the above citations, and in the title of this essay as well, is tenable or whether it is based on a pastiche of preconceptions, assumptions, nationalistic traditions, habit, and so on. It is, second, to suggest an alternative view through a consideration of Lamarck's conceptual scheme of the world; that is, through an examination of what that scheme did and did not allow. The initial task, then, is to uncover the rationale underlying the common historical conception of Lamarck as a man who missed his opportunity, and to point out its liabilities and the difficult issues it raises. To begin with, the conception was founded on the belief that certain ideas were "in the air" during Lamarck's lifetime and would, if correctly assembled, have yielded the principle of natural selection. Consider these two statements, by Loren Eiseley and Albert Vandel: We have now come, at the midpoint of the eighteenth century, into a world where several ideas are beginning to emerge without quite coalescing into an organized whole - the theory which will unite them is still to be manufactured, 7 L'id6e d'6volution 6tait clans Pair depuis la fin du XVIII e si~cle, s 6. Ibid., p. 79. 7. Loren Eiseley, Darwin's Century (Garden City, N.Y.: Doubleday, Anchor Books, 1961),p. 35. 8. Albert Vandel, "Lamarck et Darwin," Rev. Hist. Sci.. 13 (1960), 63. 444 Why Lamarck Did Not Discover Natural Selection A belief in airborne ideas encourages a particular standard of judg- ment in appraising the work of Lamarck and of course of other natu- ralists of the period as well; namely, their grasp and use of the readily available airborne ingredients to fashion a theory of evolution, and their distance from what might be acknowledged as an acceptable theory. Eiseley notes, for instance, that "Buffon managed, albeit in a somewhat scattered fashion, at least to mention every significant ingredient which was to be incorporated into Darwin's great synthesis of 1859." Eiseley goes on to say, however, that Buffon "did not.., quite manage to put these factors together. ''9 Vandel tells us, on the other hand, that the idea of evolution which was in the air, "devait ~tre clairement expos6e par Lamarck, tout d'abord dans les ouvertures de ses cours de zoologie, puis dans la Philosophie zoologique." 10 Now one of the problems with espousing the notion of airborne ideas is quite precisely illustrated by these contrasting conceptions of their nature: in what sense, one may ask, were evolutionary ideas in the eighteenth-century air? Were they there like so many flies in a swarm, ready to be picked off; or were they more like pollen dust, rather diffused and impalpably present? The notion of muffing it obviously hangs in the conceptual balance. One can hardly muff some- thing that is not either near at hand or already in hand. A more basic problem lies in considering the very existence of airborne ideas: were evolutionary ideas in the air all along for Lamarck, or were they there only because we recognize them from our more privileged-because-distant vantage point? A twentieth-century vantage point, after all, allows us to take in the whole range of eighteenth to nineteenth-century biological speculations, irrespective of national or linguistic differences. It also allows us to line up and assay all those speculations with respect to an ultimate, half-century-later standard; we know where all those speculations were headed. In effect, it would seem crucial to adjudge whether evolutionary ideas were in the air for Lamarck, or whether they were there only in retrospect. Not only must we determine in just what sense, if any, ideas were in the air, and for whom they were in the air, but also - if Eiseley's and Vandel's statements are to be taken as prototypic - we must wrestle with the adequacy of particular versions of evolutionary theory. In other words, given evolutionary airborne ideas, is any assemblage of them a theory of evolution, or is there only a preferred theory? Does a 9. Eiseley,Darwin's Century, p. 39. 10. Vandel, "Lamarck et Darwin," p. 63. 445 MAXINE SHEETS4OHNSTONE more or less diverse assemblage of the ingredients constitute a theory of evolution, as Vandel would seem to suggest, or must a much more tightly unified theory be made from the ingredients, as Eiseley seems to suggest? Just as one's answer to the earlier set of questions is com- plicated by questions of apparency, discovery, hindsight, and the like, so one's answer to the present question is complicated by one's own preferences and readings of history. Ignoring the problems and complications posed by airborne ideas and proceeding simply (if naively) on the assumption that Lamarck was aware of all of the necessary ingredients of a bona fide theory of evolution, one might understandably be led to wonder how it was that Lamarck did not construct the "great synthesis." Airborne ideas, after all, supply only the opportunity for the synthesis; they do not reveal anything about how or why Lamarck did not come to formulate it. If we are to probe the rationale underlying the conception of Lamarck as a man who missed his opportunity, we shall have to consider not only the notion of airborne ideas but typical historical characterizations of Lamarck as well. To ask why it is that Lamarck did not seize upon the principle of natural selection and thus ultimately upon the currently accepted theory of evolution is to ask in a quite specific sense why Lamarck failed. It implies that Lamarck sought something, and that he was unsuccessful in attaining it. Since failure can only be predicated of those who try, Lamarck's lack of appreciation of the principle of natural selection can be adjudged a failure only if he is viewed as having tried somehow to arrive at it. The question of whether Lamarck was in fact aiming in that direction is of critical importance. H But that very question has been skirted altogether; if we assume eighteenth and nineteenth-century evolutionary airborne ideas and the subsequent Darwinian synthesis, it appears that Lamarck must have been headed in one direction and one direction only.