Darwin therefore faced only two widely discussed evolutionary systems as he formulated his own. Both were hierarchical, and both proposed an elusive higher-level force of progress, paired with a palpable but limited lower-level force of adaptation. Darwin must have been struck by the enigma that what he could see didn't matter (in the long run of evolutionary advance), and what mattered couldn't be seen. How much of his distinctive single-level theory of extrapolation arose in reaction to this intractable dilemma of hierarchical theories posed in the old and invalid style by Lamarck and Chambers? Hierarchy, as this chapter holds for its primary theme, has been a crucial ingredient of evolutionary theories from the start, and may be more responsible than we have recognized for the eventual character of Darwin's system.
* Spencer's star has fallen dramatically. He was once renowned as a polymathic philosopher; he is now generally regarded as an unread eminent Victorian with acute logorrhea. But he can lay claim to at least one undoubted legacy in our parish; he popularized and won acceptance for the name of our subject, a word that Darwin initially rejected and adopted with resignation only late in life after Spencer's usage had triumphed (Gould, 1977b) — evolution.
* Meaning, of course, not subjectivity in argument, but selection on organisms, or persons. This term became popular in Germany via Haeckel's theory of structural hierarchy (see pp. 208-210, this chapter), in which the body of an organism — Eine Person — enjoyed no special status, but merely represented one level of a six-tiered system ranging from “plastids” (subcellular parts) to “corms” (colonies). I rather wish that we could use this strong, jargon-free term today — for I would gladly adopt “personal selection” in preference to “organismal selection.” But “personal” encompasses, alas, too wide a range of different meanings in the American vernacular, and I therefore desist. This charming term of ordinary language has held fast in at least one area, however. The parts of siphonophores (entire organisms by homology) are called “persons” — even in technical literature, where we can read about “polyp persons” and “mudusa persons” as “organs” of the differentiated colony.
* This remarkable passage anticipates our modern debates about the efficacy of species selection. Weismann's analogy surely holds: this particular case involves no directional selection, but only a sorting out and consequent balance among three species, each in its proper place — just as lung, kidney, and heart develop where they should, and to their appropriate size. However, if such a competition led not to balance and stability, but to differential birth and death of the entities involved, then we could speak of directional species selection. This argument cannot apply at a lower level within an organism, for lung cannot defeat liver without destroying the entire system (but consider cancer as an event of this type). Nonetheless, the higher level version remains potentially valid for competition among species, for the success of one bird species over another will not cause an island to founder into the ocean. Species selection does operate in this manner — and some critics (e.g. Maynard Smith, 1988) have denied a creative status to this higher level because species selection only sorts entities already shaped by organismal selection, a position that I shall challenge in Chapter 8). After all, organismal selection also works only by sorting variants produced at a lower level — yet we rightly deem such a process creative in the building of adaptations.
* The reference to Columbus and his egg puzzled me. The line is often quoted by Darwin scholars, but never explained — so either everyone (but me) knows the old tale, or else most people share my ignorance, and pass the issue by in embarrassed silence. Darwin apparently cites the story as a standard motto, or a schoolboy tale taught to everyone. But modern Americans (of my generation and younger) do not know the story — at least in my informal, but reasonably obsessive, survey. I asked several older Europeans, and caught a ray of light because some recalled such a tale from their distant educational pasts, but couldn't dredge up the details. Finally, the letters column of the New York Times came through. The old chestnut — this one I do know — about balancing an egg at the Spring equinox received an ample airing in 1989, both in editorials and letters. A Mr. Louis Marck unwittingly submitted this lovely resolution of Darwin's puzzling line in a letter of March 26 entitled “Columbus also had a way with eggs”:
In “It's Spring. Go Balance an Egg” (editorial March 19), you say that cheaters “crack the shell to create a flat bottom.” According to a tradition strangely unknown in this country, one person who did that very thing, not as a cheater, but to prove a point, was Christopher Columbus.
My German dictionary of quotations places the apocryphal incident in 1493, at a banquet given in honor of Columbus by Cardinal Mendoza. When the difficulty of his voyage of discovery was put into question, Columbus challenged his interlocutors to balance an egg. When they failed, he did it by cracking the shell.
In German, as well as Spanish, “the egg of Columbus” has become proverbial for solving a difficult problem by a surprisingly simple knack or expedient.
* Since these words directly follow the statement, quoted on p. 230, about division of labor in political economy, Schweber locates a primary influence in this interdisciplinary transfer — not only, of course, via the specific linkage in this particular quotation, but primarily because the dominant political economy of individualism, the philosophy of Adam Smith, Jeremy Bentham and scores of followers, had always been a central inspiration for Darwin from the Malthusian insight onward — see pp. 121-125 and Schweber, 1977.
* Darwin's abysmal handwriting causes endless trouble for scholars. All historians have recognized the crucial status of this final sentence, but each major exegete reads the line in a different way. Ospovat (1981, pp. 180-181) offers the following interpretation: “This is not final cause, but mere results from struggle, (I must think out this last proposition.)” Browne's version (1980, p. 71) reads: “This is not final cause but mere result from struggle (I must think out this last proposition.)” And Kohn (1985, p. 256) offers this deciphering: “This is not final cause, but more [a] result from struggle, (I must think out this last proposition.)” Aside from minor points of articles and punctuation, two disagreements are potentially substantial: First, did Darwin write “mere” or “more” with respect to struggle? “Mere” would be stronger, for then the higher order harmony of ecosystems becomes nothing but a consequence. But “more” still conveys the same sense — for higher order maximization of life would still represent more a consequence of individual struggle than anything else. Second, did Darwin say that maximization is not a final cause (Ospovat, Browne, Kohn), or does he choose to view such abundance of life as the final cause of struggle (Schweber)? These different readings seem to suggest a serious discrepancy, but, in fact, the meaning will be much the same in either case. For Darwin tells us, one way or the other, that individual struggle provides the generating cause, with maximization of life arising as a consequence. Thus, Darwin argues either that Aristotle's notion of “final cause” (“purpose” in the vernacular) has no place in science (since maximization of life only represents a result of struggle); or he states that we may continue to use the term “final cause” in an informal sense, so long as we acknowledge the underlying mechanism, or efficient cause, producing the phenomenon. (We may, in this case, view maximization as a “final cause” so long as we recognize its origin in struggle, and not in created harmony.) The same terminological ambiguity continues today in evolutionary theory. We use the language of final cause, or purpose, in describing adaptation, if only because we do not wish to abandon ordinary language. We say that giraffes evolved long necks “in order to” eat high foliage. But we recognize the causal basis of such adaptive “purpose” in natural selection by unconscious organismic struggle.
* If historians and historically-minded scientists, myself included, often develop an admiration bordering on reverence for Darwin, our judgment arises from his persistent thoroughness,
his insistence on following a train of complex thought into all ramifications and difficulties, and his internal need to resolve each and every little puzzle before achieving satisfaction. Darwin therefore, over and over again, provides resolutions to puzzles that none of his contemporaries even considered or conceptualized. In this sense, no other evolutionist of his generation came close to rivaling Darwin in sophistication — and extensive logical sloppiness permeates the work of many other thinkers. Darwin never resolved several difficult issues (progress, divergence), but he thought about them with almost chilling clarity and integrity.
* I don't wish to jump the gun towards modern incarnations in this historical chapter, but I can't resist noting that this style of treating adaptation vs. constraint has been upheld by Darwinians ever since, thus generating the extreme frustrations of iconoclasts and reformers who wish to assert the importance of constraint in setting — not merely limiting — evolutionary pathways. Later Darwinians (often much more extreme than Darwin himself, and much more inclined to demote constraint even further) would frequently deny that they ignored constraint, pointing to a footnote or side comment that made concession by lip service to the possibility of such influence. But such purposefully restricted acknowledgment cannot count as balance, pluralism, or fairness. Rather, such treatment amounts to classical dismissal by the proper criterion of relative frequency! — and the frustrations of a C. H. Waddington or an E. C. Olson (at the Chicago centennial meetings of 1959) must be understood as deep and justified (see Chapter 7). Most people don't appreciate the style and power of relative frequency, and they will misread the strategy of dismissal by footnote as adequate pluralism rather than sharp rejection. I will never forget George Oster's reply to John Maynard Smith at the Chicago macroevolution meeting in 1980 (cited in full on p. 1023), when John insisted that he had (as an adaptationist) always acknowledged constraint, and George, recognizing footnote and side commentary as dismissal, replied: “Yes John, you may have had the bicycle, but you didn't ride it.”
* I shall discuss, in subsequent sections of this and the next chapter, the functionalist (Paley) vs. structuralist (Agassiz) versions of natural theology, the central role of laws of form in the pre-Darwinian evolutionary debates (particularly the struggle between the structuralist Geoffroy Saint-Hilaire and the functionalist Cuvier), Darwin's own treatment of constraint and correlation of growth, alternatives to Darwinism based upon the centrality of constraint (Galton's polyhedron, various theories of orthogenesis, Bateson on homeosis, de Vries on saltation, Goldschmidt on jumps within channels). The structuralist alternative has always been pursued as an active option by some of the finest thinkers in our field.
* Not all biologists, by any means, favored the arguments of natural theology. Our anglophone parochialism leads us to emphasize this attitude, which held greater sway in Protestant Britain than elsewhere (and had much less influence in Catholic France). Many of the continental formalists, for example, maintained little enthusiasm for such direct providentialism, and tended either towards a pantheism of uncaring (if pervasive) divine presence, sometimes even to materialism (Geoffroy as a child of the Enlightenment), or at least towards the less radical notion that God made nature's laws and then bowed out of her affairs.
* The word adaptation did not enter biology with the advent of evolutionary theory. The Oxford English Dictionary traces it to the early 17th century in a variety of meanings, all referring to the designing or suitability of an object for a particular function, or the fit of one thing to another. The British school of natural theology used “adaptation” as its standard word for illustrating God's wisdom by the exquisite fit of form to immediate function. Darwin, in borrowing this term, simply followed an established definition while completely revising the cause of the phenomenon.
Paley frames his hypothetical opponent as a somewhat caricatured workbench materialist who believes that all natural order arises from physical laws. For Paley, this opponent exists in two versions, one more dangerous — the true atheist who denies God outright; and the theist who has abandoned a directly caring and providential God for a deity who set up the laws of nature at the beginning and then bowed out (or the deist who sees spirit in everything, but calls this directing force physical law, and owns no caring, personal God). Apparently, Paley never conceptualized, as another potential opponent worthy of explicit refutation, the possibility of a principle of selection, in Darwin's version or otherwise. That is, his caricature depicts order as arising from laws of nature, but he never imagines that good order could also emerge as a residue of trying many things out and rejecting most. Such selectionism represents, to us today, an obvious potential alternative to Paley's only conceptual model for order without apparent purpose: direct construction by the action of physical laws.
* Agassiz stuck resolutely to this system until his dying day, despite collapsing evidence, particularly for the union of Coelenterata and Echinodermata within the Radiata (a subject of much personal research by Agassiz). His last, posthumous article, “Evolution and Permanence of Type” (1874), mounts an attack on Darwin from the perspective of this fourfold taxonomy. A good deal of filial piety must lie behind Agassiz's loyalty, for Cuvier, at the end of his life, had befriended the young and inexperienced Swiss naturalist, and even passed on to Agassiz the project that would assure his later fame — a monograph of all fossil fishes. This union also includes a powerful irony, for Cuvier was the most prominent of all functionalist thinkers, and Agassiz uses their shared taxonomic framework as an ultimate defense of formalism. But the richness of great and expansive systems (like Cuvier's) allows such multiplicity of use and interpretation — and sets the curious phenomenon of strange bedfellows, both in politics and intellectual life. Cuvier fancied himself as a committed empiricist. He took the quadripartite system (so amenable to formalist interpretation) as a “given” not particularly subject to analysis at all, and he then lavished his functionalist interpretations on the myriad modifications for adaptive purpose within each plan.
* The original version comes from Pliny, quite a “Renaissance man” himself, who cited Apelles from ca. 325 bc. A last, by the way, is a shoemaker's model foot, not an abstract statement about stubbornness. The original — ne supra crepidam sutor iudicaret — literally states that a cobbler should not judge above his last, and therefore includes some social bias amidst its narrowness.
* Geoffroy wrote this work before Owen's codification of the terms “homology” and “analogy” in their modern meaning. Unfortunately — for the resulting situation could not be more confusing — Geoffroy used the word analogy (theorie des analogues) for similarities of common generating type that we now call homologies. In this chapter, I will use the modern terminology, and only retain Geoffroy's name in direct quotations (but always with a reminder that he speaks of homology by our reckoning).
* Goethe's theory encompasses only the lateral and terminal organs, not the supporting roots and stems. Goethe was often castigated for this omission, unfairly I think. (A theory for all appended parts cannot be dismissed as a mean thing, even if the framework remains unaddressed.) Goethe became quite sensitive to such criticism, and defended his failure to consider roots by heaping disdain upon such lowly parts: “My critics have taken me to task for not considering the root in my treatment of plant metamorphosis ... I was not concerned with it at all, for what had I to do with an organ which takes the form of strings, ropes, bulbs, and knots, and manifests itself in such unsatisfying alternation, an organ where endless varieties make their appearance and where none advance. And it is advance solely that could attract me, hold me, and sweep me along on my course. Let everyone to his own way. Let him, if he can, look back upon forty years of accomplishment, such as the Good Genius has granted me” (from unedited paragraph written in 1824, quoted in Mueller and Engard, 1952).
* Note the isomorphism between Goethe on plant morphology and Lamarck on the mechanics of evolution (see Chapter 3).
Both argued that a progressive force dominated the entire system — yielding, if unopposed, a march up the chain of being for Lamarck and a progressive refinement of organs up the stem for Goethe. But both scientists bowed to the empirical data of greater complexity and messiness in nature. Both therefore needed to postulate orthogonal or deflecting forces to produce discontinuities and lateral morphologies — local adaptation for Lamarck and cycles of expansion and contraction for Goethe.
* Conditions d'existence became Cuvier's motto for his functionalist credo. By this phrase, as evident in this quotation, he did not only designate adaptation to external environment, but also coordination of parts by and for the pursuit of proper function. Note that Darwin used Cuvier's phrase in identifying the functionalist pole of the dichotomy (1859, p. 206, and Section 1 of this chapter).
* This doctrine, called “correlation of parts,” spawned the legend, much abetted by Cuvier's overenthusiasm in the Discours preliminaire, that paleontologists can reconstruct entire skeletons from single bits of bone. (We may do so inductively by knowing that a tooth of distinctive form only grows in a rhino's jaw, but we cannot — as Cuvier hoped and hyped — make such reconstructions analytically. Cuvier, in fact, admitted as much by stating that current practice, in the light of our analytical ignorance, must be empirical — and by bragging that he could outdo any competitor by virtue of his superb collection of skeletons at the Museum! — see Gould, 1991b.)
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