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The Meaning of EvolutionThe Morphological Construction and Ideological Reconstruction of Darwin's Theory$

Robert J. Richards

Print publication date: 1992

Print ISBN-13: 9780226712024

Published to Chicago Scholarship Online: March 2013

DOI: 10.7208/chicago/9780226712055.001.0001

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Emergence of Evolutionary Theories of Species Change

Emergence of Evolutionary Theories of Species Change

(p.63) 4 Emergence of Evolutionary Theories of Species Change
The Meaning of Evolution
University of Chicago Press

Abstract and Keywords

This chapter describes the early discussions on embryological recapitulation and species evolution and Charles Darwin's views regarding them. From ancient time to the beginning of the nineteenth century, ideas about species change smoldered but failed to ignite the imaginations of most naturalists. Even Aristotle had acknowledged the creation of new kinds of animals through hybridization, and he elaborated the theory that spontaneous generation of insects, worms, and marine invertebrates would later give support to wobbly proposals of species evolution. Although Georges Leclerc, Comte de Buffon, had initially opposed the idea of transmutation, certain breeding experiments and theoretical considerations brought him to the view that the originally created kinds of animals had degenerated into the myriad of species because of the influence of the environment.

Keywords:   embryological recapitulation, species evolution, Charles Darwin, Aristotle, transmutation

From ancient time to the beginning of the nineteenth century, ideas about species change smoldered but failed to ignite the imaginations of most naturalists. Vague notions of transmutation can be traced to classical Greece, where Anaximander (610–546 B.C.), Anaxagoras (534–462 B.C.), and Empedocles (fl. 444 B.C.) concocted fables about the emergence of new sorts of animals that Aristotle (384–22 B.C.) critically analyzed but did not simply dismiss as incompatible with healthy conception.1 Even the Philosopher acknowledged the creation of new kinds of animals through hybridization; and he elaborated the sort of theory about the spontaneous generation of insects, worms, and marine invertebrates that would later give support to wobbly proposals of species evolution.2 Indeed, the venerable belief in such “equivocal” productions of ignoble creatures helped convince Francis Bacon (1561–1626) (p.64) that while “the Transmutation of Species is, in the vulgar Philosophy, pronounced Impossible,…seeing there appear some manifest Instances of it, the Opinion of Impossibility is to bee rejected; and the Means thereof to bee found out.”3 Subsequently Benoit de Maillet (1656–1738), Julien Offray de La Mettrie (1709–51), Pierre Louis de Maupertuis (1698–1759), Denis Diderot (1713–84), and Immanuel Kant (1724–1804) all spun gauzy notions about species change.4 The great natural historian and founder of the Jardin du Roi, Georges Leclerc, Comte de Buffon (1707–88), had initially opposed the idea of transmutation, but breeding experiments and certain theoretical considerations brought him to the view, in his essay “De la dégénération des animaux” (1766), that the originally created kinds of animals (now the genera and families) had, because of the influence of the environment, degenerated into the myriad of species now populating this decidedly ancient earth.5 Buffon's conviction was not far different from that of his enemy Linnaeus (1707–78), who proposed in his later years the mechanism of hybridization to produce new species from original kinds. Buffon's and Linnaeus's quasi-evolutionary beliefs became known to Erasmus Darwin (1731–1802), who advanced a more radical theory of species alteration in his two-volume Zoonomia (1794–96), according to which that original “living filament” created by God, through irritable response and acquired (p.65) habit, became transmuted over eons into all the warmblooded animals.6 Charles Darwin (1809–82) first brushed against the hypothesis of species evolution, as he recalled in his Autobiography,7 in reading his grandfather. But undoubtedly the equally important early influence on Darwin, as well as the singular stimulus for his contemporaries (especially Robert Grant, Herbert Spencer, Robert Chambers, and Ernst Haeckel), was Jean-Baptiste de Lamarck (1744–1829).

Darwin had learned of Lamarck's hypothesis under the tutelage of Robert Grant (1793–1874), who directed him in a vocational study of invertebrates while he was a very young medical student at Edinburgh (1825–27); and during the voyage on board HMS Beagle (1831–36), Darwin had leisure to examine Lamarck's Histoire naturelle des animaux sans vertèbres (1815–22). In 1832, when sailing down the eastern coast of South America, he received the second volume (1832) of Charles Lyell's Principles of Geology (1830–33). That book contained a sustained presentation and sharply negative critique of Lamarck's arguments “in favour of the fancied evolution of one species out of another.”8

Lamarck had first suggested species change in 1800 but developed his theory more fully in later works, especially in his Philosophie zoologique (1809). It was this treatise that Lyell analyzed. Lamarck proposed that simple monadic life bubbled up from the muck under the influence of the imponderable fluids of caloric and electricity. These forces, which continued to operate even today, caused those elementary vesicles born of slime to become more complex, eventually producing organisms that internalized the fluids. The incessant excavations and articulations by the internal fluids over (p.66)

Emergence of Evolutionary Theories of Species Change

FIGURE 11. Jean-Baptiste de Lamarck, 1774–1829; engraving in 1821. Wellcome Institute Library, London.

(p.67) generations led to greater perfection (i.e., complexity) of organisms, while the heritable effects of habit modified their parts to fit them into a changing environment.9 Unlike Treviranus, Tiedemann, and later Darwin, Lamarck did not appeal to evidence of great extinctions of animals to argue for transformations in organic life. The fossil evidence that Cuvier accumulated had already been piously wedded to the geological theory of catastrophism, while Lamarck cast his lot with uniformitarianism—the theory that geological formations resulted from processes occurring slowly over vast reaches of time instead of being wrenched into place through forces ultimately controlled by an unpredictable Deity. Seemingly extinct creatures, he urged, had been transformed into contemporary species, or might even be found in unexplored regions of the globe.10

Lamarck did not use the term “evolution” to describe the progressive transformation of animal species; rather he referred to the process, in obvious deference to his mentor Buffon, in a negative way, as the inverse of that “degradation [dégradation]” we observe as we cast our eye down the scale of life.11 Lyell gave currency to the English usage of the term “evolution” by applying it indifferently to Lamarck's theory of transmutation and Tiedemann's idea that during embryogenesis the brain of higher animals evolved through stages of the lower. Lyell, however, seems to have gotten the sterling for his (p.68)

Emergence of Evolutionary Theories of Species Change

FIGURE 12. Sir Charles Lyell, 1797–1875, who wrote an extended critique of Lamarck's and Tiedemann's evolutionism; lithograph of portrait done in 1849. Wellcome Institute Library, London.

(p.69) coinage from Serres, as well as perhaps from Joseph Henry Green and fellow Scot Robert Grant.12

Serres, Grant, Green, and Lyell on Recapitulation and Evolution

I have argued that the principle of recapitulation transmitted to the idea of species alteration certain considerations born out of embryological theory. The term “evolution” indexes this transmission. The Germans, especially Tiedemann and Meckel, thought of the principle of recapitulation as reflecting a unity of law that accounted for both individual development and species development. In his own work on recapitulation, which owed much to the Germans, Serres used the expression théorie des évolutions13 ambiguously to refer to the recapitulational métamorphoses of organic parts in the individual and the parallel changes one sees in moving (intellectually) from one family of animals to another and from one class to another. A similar usage was introduced to English audiences at about the same time by two medical zoologists of very different theological and metaphysical persuasions—Robert Grant, in 1826, and Joseph Henry Green, in his Hunterian Lectures for 1827 and 1828.

While at medical school in Edinburgh Darwin made the acquaintance of Robert Grant (1793–1874), who directed him in the investigation of marine invertebrates. In his Autobiography Darwin recalled that Grant “one day, when we were walking together burst forth in high admiration of Lamarck and his views on evolution.” Darwin reacted, he remembered, “in silent astonishment”; but added, perhaps in (p.70) defense of his own accomplishment, that the encounter was “without any effect on my mind.”14 Grant, who received his M.D. from Edinburgh in 1814, traveled through Germany and lingered in France, where, despite Cuvier's towering authority, he became an admirer of Lamarck and a friend of Geoffroy. In 1827 Grant was appointed to the chair of comparative anatomy at the new University of London after the city council refused to meet the monetary demands of the very German Professor Johann Friedrich Meckel, to whom the position had first been offered. In his university capacity, Grant delivered several series of lectures in which recapitulation became the central theoretical focus.15 These lectures might only have hinted at transformationism, but even that would have been obscured by his exceedingly dour style, which was characterized for Darwin by a friend as “rather too grave, & rather too pedantic, too much given to coin hard words, at times…eloquent & animated, generally verbose & lengthy.”16 He was more forthright as a younger man. In an early article (1826), published under a discreet veil of anonymity, Grant declared for Lamarck. The French zoologist, according to Grant, had found “a key to the profoundest secrets of nature,” namely, that infusoria and worms had spontaneously been generated and “that all other animals, by the (p.71)

Emergence of Evolutionary Theories of Species Change

FIGURE 13. Robert Edmond Grant, 1793–1874, whose praise for Lamarck surprised his young friend Darwin; lithograph in 1852. Wellcome Institute Library, London.

(p.72) operation of external circumstances, are evolved from these in a double series, and in a gradual manner.”17 Though Lamarck had not engaged recapitulation theory as part of his conception, it yet became for Grant—probably because of the influence of Geoffroy and Serres—another magical key. It unlocked the secret unity that spread throughout the animal kingdom and revealed the common set of laws that made such unity comprehensible, without, he would argue to friends and insinuate in public lectures, the need of appeal to a meddlesome Deity. Desmond, who has provided the most thorough and subtle account of Grant's life, contends that this Scots materialist vividly illustrated for the more orthodoxly sober, like Richard Owen, the cautionary implications of evolutionary theory.18 Despite, however, the radical dangers to religion and social polity that evolutionary theory might have suggested to some, it could be tamed, as Joseph Henry Green (1791–1863) demonstrated.

Green, who became professor of surgery at the new King's College in 1830, had been educated in Germany and cultivated a knowledge of transcendental anatomy, especially the works of Oken, Tiedemann, and Carus.19 Green was encouraged in this philosophical-physiological pursuit by his friendship (p.73) with Samuel Taylor Coleridge (1772–1834), who knew thoroughly the views of Erasmus Darwin, Treviranus, and Tiedemann. Indeed, Green's Hunterian lectures of 1827 and 1828 were tinctured with Coleridgean “evolutionary” individualism—an elixir later stimulating Herbert Spencer (1820–1903) as well.20 In these lectures, Green suggested to his listeners (among whom was his protégé Richard Owen, and perhaps Lyell)21 that nature, in producing the great types of animal organization, labored “to complete in the evolution (p.74) of the organic realm” her highest Idea, namely, man. This same progressive tendency expressed itself in the parallel evolution of the embryo: “Hence the states, which the individual passes through in all the epochs of its embryonic being, and which having been disappear, are preserved in Nature, and maintain the rank of external and abiding forms.”22 Green hastened to add that this “series of evolutions from the lowest to the highest” occurs not linearly, but as a tree whose “infinitely diversified [branches] manifest the energy of the life within.” Nor did the productive force operate according to “the fanciful scheme” of Lamarck;23 rather, “the ascent is (p.75) the indication of a law, and the manifestation of a higher power acting in and by nature.”24

Desmond argues, almost convincingly, that Green rejected the Lamarckian notion of a lower species being transformed into a higher. He thinks that Green denied species evolution principally because of his Coleridgean class politics. That political attitude, according to Desmond, decreed a stately hierarchy of social orders, while in Green's nostrils the descent thesis reeked of political radicalism. Green must have believed, Desmond reckons, that the spoiled scientific carrion of evolution could only incite the demoecratic levelers.25

The student of history suspicious of a priori schemes, such as those advanced by social constructionists, will forbear immediate acceptance of Desmond's thesis for at least two reasons. (p.76)

Emergence of Evolutionary Theories of Species Change

FIGURE 14. Joseph Henry Green, 1791–1863, an early English evolutionist and transcendental morphologist, and mentor of Richard Owen; lithograph of him at age fifty-five. Wellcome Institute Library, London.

(p.77) First, he claims that Green, in rejecting “the fanciful scheme of Lamarck,” also denied a historical transformation of species. But Green's lectures of 1827 and 1828 indicate clearly that he demurred, not to the idea of genealogical descent, but to two attendant features of Lamarck's scheme, namely, the proposals for the mechanism and for the mode of descent. Green denied Lamarck's “inherent” natural source of species change, since the Frenchman's theory was that “in which the ground and cause is everywhere meaner and feebler than the effect.” Green rather insisted that “the ascent is the indication of a law, and the manifestation of a higher power acting in and by nature.”26 He also maintained against Lamarck that “this gradation and evolution of animated nature is not simple and uniform; [rather] nature is ever rich, fertile, and varied in act and product; [like] some monarch of the forest.”27 Evolution, he argued, spread through great tree-like ramifications. Thus it was not species transmutation per se to which Green objected but to the materialistic and simplified model of that process. Whether he actually believed that one species gave birth to another, even under divine edict, would be difficult to say, since his transcendentalist language slides over those clear distinctions that post-Darwinians require. Certainly there is nothing in his Hunterian lectures that excludes the idea of a gradual transmutation; indeed, given his familiarity with Lamarck's and Tiedemann's ideas and his use of the language of “ascent…by nature,” a straightforward interpretation would have him endorsing progressive species alteration. Like Grant and the Germans whom they both read, Green thought of progressive ascent in embryo and species as comparable transformations that expressed a unity of law governing the living world—and for Green such biological symmetry had the added purpose of lifting our spirits to the Divine. Green's shaded remarks on transmutation but clear perspective on (p.78) the originating sacred cause of species would later be reflected in the ambiguous but safe position of his protégé Richard Owen. Yet just as in the case of Owen (see below), it is obvious that Green did not quite formulate his lectures with our precise question in mind. Rather, as a Germanophilic teleologist of religious passion, he desired to evacuate the possibility that matter alone could rouse itself to more perfect productions.

But even if we drop the question of whether Green was really a species evolutionist—he was certainly an embryological evolutionist who endorsed “Tiedemann,28 who was a species evolutionist—a second consideration needs to be introduced, which leads to the vital center of Desmond's thesis. This concerns the priority of motivation that he has assumed. Desmond has set the friends of Coleridge against the Lamarckians because of class politics rather than because of the intellectual commitment to a certain kind of metaphysics of nature. But one must remember that the Coleridgean belief in the ascent of the individual fed the Lamarckian evolutionism of that anarchistic class smasher Herbert Spencer,29 and at the same time it succored the enlightened radicalism of John Stuart Mill.30 Most scientific theories are politically insipid. The same theory can be consumed by thinkers of very different social ideals (e.g., the evolutionism taken in by Spencer and Marx, or Wilson and Gould). So a particular theory may be chosen for reasons other than a distinctive political flavor. Green perhaps inclined toward the aristocratic, but his Platonic and teleological impulses, along with his detailed knowledge of comparative anatomy—of the sort which led his German guides to species transformation—would have been enough to justify a theory that had nature striving toward greater individuality and consciousness, culminating in (p.79) the precast ideal of rational humanity. A perfectly condign analysis might have Green adopting his theory of the law-governed development of species independently of any political conviction, the reason being its congenial metaphysical implications and the empirical evidence supporting it. Such an analysis, though, might subsequently show how Green then used his science to support a favored political position. Any assumption of the priority of the political motive in determining a scientific stand may vent a late twentieth-century political-historical passion more than an early-nineteenth-century natural-historical one.

But enough (perhaps more than enough). Green's importance—for this historian at least—lies in his use of the term “evolution” to describe, and thus implicitly to identify, the development of the embryo and the parallel development of species and in his formulation of the Germanic notion that a common law, for him a divine command, governed this dual evolution.

Lyell never mentioned Grant or Green in the Principles of Geology, though the likelihood of his knowing their works was great.31 He did, however, cite Serres and refer to Tiedemann in evaluating the evidence which the principle of recapitulation provided for a real evolution of species.32 Lyell thought the principle really only demonstrated a Cuvierian or Geoffroy-like unity of plan within the animal kingdom—transcendental relations but no real historical links. Nonetheless, by use of the term “evolution” he suggested to a wide readership the intellectual connection between the theories (p.80) of individual (that is, embryological) evolution and species evolution. One of those who very carefully dissected Lyell's remarks in the Principles of Geology was Darwin.

Darwin's Theories of Species Change

After returning from the Beagle voyage in October 1836, Darwin began arranging and cataloging his specimens. In March of the next year he set down in his “Red Notebook” brief speculation on species change.33 He further reflected on such changes in a series of notebooks beginning in late spring or early summer 1837, the “Transmutation Notebooks.” In September 1838 he read Malthus, which, as he recalled, gave him “a theory by which to work.”34 The catalyst of Malthus precipitated out of Darwin's thought the bare structure of his mechanism of natural selection. He further developed his ideas about species change in two essays, one in 1842 and its expansion in 1844. These became the spine for the more comprehensive expression of his theory, which he began drafting in 1856. The work on this book, which was to be called “Natural Selection,” was interrupted in 1858 by a letter from Alfred Russel Wallace (1823–1913) that outlined a theory of transmutation very similar to the one Darwin had been laboring over for twenty years. In a white heat, he condensed his huge manuscript and added in smaller compass the further chapters he intended. He published the Origin of Species in 1859. Through this long gestation, one can distinguish certain stages in the development of his theory.35

(p.81) In the earliest stage,36 Darwin—reflecting ideas of his grandfather and Lyell—considered species to be comparable to individuals: under the influence of the environment, species changed over time; but reaching the end of their allotted years, they gave birth to new species and then died off. In the second stage, Darwin retained the adapting mechanism of the heritable effects of environmental agents (taking many hints from his grandfather and Lamarck) but gave up the idea of species having a definite term of life. He supposed that there would be a branching of species, with some continuing to “progress” and “perfecting” through different forms, while others, because of not adapting fast enough, would go extinct.37 This, Darwin thought, was comparable to what occurred when individuals, having adapted to their circumstances, produced offspring with the new modifications; the parents, however, had to die so that progeny could take their place: “generation of species like generation of individuals.—Why does individual die, to perpetuate certain peculiarities, (therefore adaptation)…Now this argument applies to species.—If individual cannot procreate, he has no issue, so with species.”38 Like his grandfather, Grant, Green, and the German transcendentalists, Darwin initially understood (p.82) the goal of species transformation to be higher creatures, ultimately man: “Progressive development gives final cause for enormous periods anterior to Man.”39

In the third stage of his reflections, Darwin realized that the mechanism of the direct effects of the environment would not easily adjust organisms to their surroundings. He then proposed that an animal would develop new habits, which would adapt it to a shifting environment, and that these habits would over time be sifted, so that individual peculiarities would fall out. Finally, by dint of repetition over countless generations, such general habits would become instinctive. These finely articulated innate behaviors would in their turn slowly alter anatomical traits, changing the character of species:

an action becomes habitual is probably first stage, & an habitual action implies want of consciousness & will & therefore may be called instinctive.—But why do some actions become hereditary & instinctive & not others.—We even see they must be done often «to be habitual» or of great importance to cause long memory.—structure is only gained slowly.—therefore it can only be those actions, which Many successive generations are impelled to do in same way—The improvement of reason implies diversity & therefore would banish individual, but general ones might yet be transmitted.40

By postulating gradual modifications introduced by instinct, Darwin constructed his mechanism to Lyellian uniformitarian specifications, while rejecting what he took to be the Lamarckian attribution of conscious will effort to animals.41

In late September 1838, Darwin read Malthuss Essay on (p.83) Population, which brought him to appreciate the sort of pressure to adapt that would be produced by great fecundity. In this light he immediately understood the advantage a favorable trait would have and how it might gradually alter species:

[Sept.] 28th. «I do not doubt, every one till he thinks deeply has assumed that increase of animals exactly proportional to the number that can live.—» We ought to be far from wondering of changes in number of species, from small changes in nature of locality. Even the energetic language of 〈Malthus〉 «Decandoelle» does not convey the warring of the species as inference from Malthus…[I]n Nature production does not increase, whilst no checks prevail, but the positive check of famine & consequently death…One may say there is a force like a hundred thousand wedges trying force 〈into〉 every kind of adapted structure into the gaps 〈of〉 in the oeconomy of Nature, or rather forming gaps by thrusting out weaker ones. «The final cause of all this wedgings, must be to sort out proper structure & adapt it to change.»42

Malthus brought Darwin to see that under increasing population pressure, the features of local environments would select, as it were, those individuals that happened to have traits which could wedge them into unoccupied parts of their surroundings—or which would give them an advantage over competitors already inhabiting particular spaces. Those with the favorable traits would live to propagate another day, while those bested would untimely perish, leaving few behind them. The selected organisms would thus be able to transmit their advantageous traits to offspring and so deliver their competitive virtues down the generations. The resulting proportional increase of those bearing the superior traits would, in the measure of time, gradually transform the species.

In the reflections of 28 September, Darwin's mechanism of (p.84) natural selection came to birth. When it did, it slowly pushed the other devices of species change to the periphery of his theory of evolution. Though he regarded these “Lamarckian” instruments as no longer central to the production of new species, he did retain them as various auxiliary mechanisms in the Origin of Species. So, for instance, anatomical changes produced through acquired habit could, as he yet maintained in the Origin, become impressed upon the hereditary substance and be passed to succeeding generations; as well, such acquired characteristics might also serve as variations upon which natural selection could operate.43 Despite the preservation of these earlier devices of species change, Darwin urged in the Origin that natural selection accomplished most of the work done in evolution.

Natural Selection as the Mechanism of Progressive Evolution

Natural selection appears to modern eyes to foredoom any notions of evolutionary progress. After all, Darwin's mechanism works on chance variations, which it selects to satisfy local requirements. Indeed, Gould, in his interpretation of Darwin, has pounded natural selection into a fine, anti-progressivist blade, which he has wielded to protect the lineage of neo-Darwinism. Gould maintains that “an explicit denial of innate progression is the most characteristic feature (p.85) separating Darwin's theory of natural selection from other nineteenth century evolutionary theories. Natural selection speaks only of adaptation to local environments, not of directed trends or inherent improvement.44 Certainly historians of this mind have the avowal of Darwin himself, when he protested against Lamarck's idea of an “innate tendency toward progressive development.”45

Scientifically sustained ideas of progress appear, from our late-twentieth-century perspective, to be tainted by foreign political agents. Within the Victorian environment of such ideas, natural selection as we now understand it might appear to be a deduction decidedly dangerous. Gould explains:

Its [natural selection's] Victorian unpopularity, in my view lay primarily in its denial of general progress as inherent in the workings of evolution. Natural selection is a theory of local adaptation to changing environments. It proposes no perfecting principles, no guarantee of general improvement; in short, no reason for general approbation in a political climate favoring innate progress in nature.46

The historian, and especially the historian-scientist, can, I believe, become too easily beguiled by the power of present scientific theory and consequently imagine that its ancestor theory carried the same “logical” implications, which are then presumed to have stood clear to the earlier practitioners. It is convenient to forget that scientific theories, like (p.86) biological species, are also historical entities whose logic must be contingently read. While Darwin did reject the hypothesis of an intrinsic cause of necessary progress buried in the interstices of organization, in the beginning he nonetheless insisted, relying on the embryological model, that animals had an internal “tendency to change,”47 which would be progressively molded by the extrinsic agency of the environment. Natural selection would exert, as it were, an external pull, drawing most organisms to greater levels of complexity and perfection.48

The magnetic attraction to perfection would be, Darwin thought, induced by the peculiar dynamic of selection. He supposed that the environment against which organisms were most often selected would be the living environment of other creatures, so that reciprocal developmental responses would be evoked throughout the system. It might be, of course, that extinction of simpler animals in a particular location would lead to some more advanced creatures becoming simplified, to backfill the gap. This would mean that some animal series might show a kind of devolution, but the trend would nonetheless be toward ever-increasing complexity. Darwin expressed his belief in a progressive, natural selection dynamic in his fourth transmutation notebook, some time in January of 1839:

The enormous number of animals in the world depends on their varied structure & complexity.—hence as the forms became complicated, they opened fresh means of adding to their complexity.—but yet there is no necessary tendency in the simple animals to become complicated although all perhaps will (p.87) have done so from the new relations caused by the advancing complexity of others.—It may be said, why should there not be at any time as many species tending to dis-development (some probably always have done so, as the simplest fish), my answer is because, if we begin with the simpler forms & suppose them to have changed, their very changes tend to give rise to others.49

Darwin's notion of an innate tendency to change gradually faded in his theory; it came to be replaced by the supposition of environmental forces producing the kind of variation that could be transmuted into progressive forms during the development of species. (Darwin did argue in the Origin that organisms, especially those in large genera, would inherit a tendency to vary and diverge from parent forms—the residual of his idea of an innate tendency to change.)50 He retained, however, his conception of a progressive dynamic; and in the Origin of Species he integrated that idea into the more general theory of divergent evolution. In large, open areas the environment of other closely related species would promote mutually adaptive lineages, the species of which would, as a result, continuously diverge and improve; for in such situations “the conditions of life are infinitely complex from the large number of already existing species; and if some of these many species become modified and improved, (p.88)

Emergence of Evolutionary Theories of Species Change

FIGURE 15. Charles Darwin; photograph taken in I860, just after publication of the Origin of Species.

(p.89) others will have to be improved in a corresponding degree or they will be exterminated.”51 The general improvements created by natural selection, Darwin suggested elsewhere in the Origin, would not be merely relative to local environments. He appears to have thought natural selection would produce ever more progressive types, so that “the more recent forms must, on my theory, be higher than the more ancient; for each new species is formed by having had some advantage in the struggle for life over other and preceding forms.”52

In the Origin, Darwin augmented the power of this progressive dynamic by attributing to natural selection the beneficent concern for the good of creatures, a concern that had been formerly expressed by the recently departed Deity. Artificial selection of animals was capricious and governed only by selfish desires of men; natural selection altruistically looked to the welfare of the creatures selected. As Darwin put it: “Man selects only for his own good; Nature only for that of the being which she tends.”53 He concluded that natural selection therefore insured progressive evolution: “as natural selection works solely by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection.”54

Lyell, Darwin's friend and mentor, had decried the belief in geological progress because it represented an unwarranted theological intrusion into science; moreover, it was a conception dangerous to the unique moral character of human beings—since man was not merely an advanced orang. Many contemporary historians have shared Lyell's concern about the intrusion of alien wisdom into science, usually today understood as conservative political ideology. They have consequently abjured any interpretation of neo-Darwinism that appears to suggest progressive development, which seems to (p.90) give succor to tainted political values. They imagine, however, that Darwin acquiesced in their understanding. But, as we have seen (and further evidence will be supplied in the next chapter), Darwin was not of a late-twentieth-century mind. Progress was the intended consequence of the model he had originally adopted for species evolution, namely, that of individual evolution. Indeed, the concepts of species change he had become familiar with from his grandfather, from Lamarck, from Grant, and, indirectly, from Tiedemann, Treviranus, Serres, and Geoffroy—all supposed progressive advance of creatures. Darwin worked a compromise in his conception of species transformation by making progress non-necessary, though general, and by placing the guide for advance in the external environment. This sort of compromise has perhaps deflected attention from the conception of embryogenesis that I believe stabilizes the core of Darwin's new theory of species evolution. We should now reconsider the gradual, uniform development of his embryological ideas and their role in his species theory.


(1.) Aristotle certainly had objections (De anima, 198B. 16–32) to Empedocles' theory that creatures might accidentally have acquired parts and those that proved most viable would survive—a vague prototype of natural selection. However, Aristotle did entertain the possibility that man and the quadrupeds might have originated through spontaneous generation of a grub, which presumably would later develop into the familiar species (De generatione animalium, 762B28–763A5). This, as well as much else in Aristotle (e.g., new kinds of animals produced through hybridization—ibid., 746A29–746B12), indicates a need for reevaluating the usual assumption that Aristotelian philosophy could tolerate no consideration of species mutability.

(2.) See preceding note.

(3.) Francis Bacon, Sylva Sylvarum; Or a Naturell Historie in Ten Centuries, 3d ed. (London: William Lee, 1631), p. 132.

(4.) For descriptions of transmutational theories before Darwin, see Bentley Glass, ed., Forerunners of Darwin (Baltimore: Johns Hopkins University Press, 1968); and Robert J. Richards, “Influence of Sensationalist Tradition on Early Theories of the Evolution of Behavior,” Journal of the History of Ideas 40 (1979): 85–105.

(5.) Georges Louis Leclerc, Comte de Buffon, “De la dégénération des animaux” (1766), in Oeuvres complètes de Buffon, ed. Pierre Flourens, vol. 4 (Paris: Garnier, 1852–1855). See also Phillip Sloan, “Buffon, German Biology, and the Historical Interpretation of Biological Species,” British Journal for the History of Science 12 (1979): 109–53.

(6.) Erasmus Darwin, Zoonomia or the Laws of Organic Life, 2d ed. (London: Johnson, 1796), 1: 509.

(7.) Charles Darwin, The Autobiography of Charles Darwin, ed. Nora Barlow (New York: Norton, 1969), p. 49.

(8.) Charles Lyell, Principles of Geology (London: Murray, 1830–33), 2: 60.

(9.) For discussions of Lamarck's theory, see Richard Burkhardt, The Spirit of the System (Cambridge: Harvard University Press, 1977); Pietro Corsi, The Age of Lamarck (Berkeley: University of California Press, 1988); and Robert J. Richards, Darwin and the Emergence of Evolutionary Theories of Mind and Behavior (Chicago: University of Chicago Press, 1987).

(10.) Jean-Baptiste de Lamarck, Systéme des animaux sans vertébres (Paris: Lamarck et Deterville, 1801), p. 407. Lamarck thought the hypothesis of general geological upheavals “a rather convenient means for those naturalists who wish to explain everything and who do not take any trouble to observe and study the course which nature follows in regard to her productions and all that constitute her domain” (ibid.).

(11.) Jean-Baptiste de Lamarck, Philosophie zoologique (Paris: Dentu, 1809), 1:220.

(12.) Adrian Desmond believes Robert Grant to have been the first to introduce the term “evolution” in its species-transforming sense into English print. See his admirable Politics of Evolution (Chicago: University of Chicago Press, 1989), p. 5. Desmond's ascription to Grant of the anonymous journal article of 1826, in which the word appeared, is not unproblematic. See n. 17, below.

(13.) Etienne Reynaud Serres, “Théorie des formations organiques,” Annales des sciences naturelles 12 (1827): 83.

(14.) Darwin, Autobiography, p. 49.

(15.) Beginning in 1833, Grant delivered a series of some sixty lectures at University College on the theme of animal unity. As he considered each organ system of man, he would conclude by pointing to comparable organs in lower animals, which were, he maintained, recapitulated in human embryogenesis. He summed up his position in the final lecture on mammals: “The transient forms of the organs in the higher classes of animals represent successively the permanent forms of the lower, and the laws of animal development have continued to operate with the same undeviating uniformity since the first appearance of animal forms on the earth, as we observe in those which govern the rest of the material world.” See the report of this lecture “On the Generative System of Mammalia,” Lancet 2 (1833–34): 1035.

(16.) F. W. Hope to Charles Darwin (15 January 1834), Correspondence of Charles Darwin, ed. Frederick Burkhardt et al. (Cambridge: Cambridge University Press, 1985–), 1: 363.

(17.) [Robert Grant], “Observations on the Nature and Importance of Geology,” Edinburgh New Philosophical Journal 1 (1826): 293–302; quotation from p. 297. Given the subject of the article, the editor of the journal (the geologist Robert Jameson), and the source of the publication, Lyell very likely read Grant's piece and would have seen the word “evolved” used in description of Lamarck's theory. The established view that Grant authored this essay is criticized by James Secord, who argues with dexterous contextuality that the piece was more likely written by the editor Jameson. See James Secord, “Edinburgh Lamarckians: Robert Jameson and Robert E. Grant,” Journal of the History of Biology 24 (1991): 1–18. While no fast facts fix the identity of the author, the essay certainly expresses a series of views close to ones Grant held.

(18.) See Desmond, Politics of Evolution, pp. 276–79.

(19.) Phillip Sloan discusses Green's background in the masterful “Introduction” to his edition of Richard Owen's Hunterian Lectures, May–June 1837 (London: British Museum [Natural History]; Chicago: University of Chicago Press, forthcoming). I am grateful to Sloan for calling Green's work to my attention. See also Desmond, Politics of Evolution, pp. 260–75.

(20.) Spencer is usually credited with giving currency to the word “evolution” in its use to describe species change. As we have seen, and more evidence will be provided below, the term was commonly used with this meaning prior to Spencer's influential marketing of it. Spencer seems to have first employed the word in 1851, in Social Statics, where he argued that the moral law, or the law of equal freedom, is the same principle that governs the organic development of men toward ever greater individuality—“an endowment,” he claimed, “now in process of evolution.” See Herbert Spencer, Social Statics, or the Conditions Essential to Human Happiness (London: Chapman, 1851), p. 440. Spencer borrowed, as he acknowledged, this conception of life as a progressive evolution toward individuality from Samuel Taylor Coleridge's posthumous essay (1848) “The Theory of Life.” See Samuel Taylor Coleridge, Miscellanies, Aesthetic and Literary: To Which is Added the Theory of Life, ed. T. Ashe (London: Bell & Sons, 1892). Coleridge used “evolution” to describe the tendency of life to attain progressively greater individuality—a view he in turn seems to have adopted from Schelling, whose works he knew extensively and intimately. Coleridge's evolution, like Schelling's, bespoke only ideal relations of species, not historical relations, a metaphysical nicety that probably escaped the young Spencer. Spencer would also have met the term “evolution” in its “species-transformation” sense in Lyell's Principles of Geology and Carpenter's Principles of Comparative Physiology (see below), both of which he read prior to composing Social Statics. See Richards, Darwin and the Emergence of Evolutionary Theories, pp. 267–69, for a discussion of Spencer's use of Lyell and Carpenter.

(21.) Lyell had undertaken serious study of Lamarck's Philosophie zoologique in late summer of 1827, while in Scotland. He returned to London the following January and remained there until his trip to Paris in May. For these months, see Leonard Wilson, Charles Lyell: The Years to 1841 (New Haven: Yale University Press, 1972), pp. 184–90. Green, who had considerable admiration for Lamarck despite certain reservations about the Frenchman's theory, began his lectures that March. Thus Lyell could have attended and would have been motivated to do so. See n. 23 below.

(22.) Joseph Henry Green, “Recapitulatory Lecture” (1828), in his Vital Dynamics. The Hunterian Oration before the Royal College of Surgeons in London, 14th February 1840 (London: Pickering, 1840), p. 103. This line comes directly from Tiedemann (see text to n. 54, chap. 3, above). The “Recapitulatory Lecture” was a transcription of Green's Hunterian Lecture for 1828. Owen was present for the 1828 lecture; see Sloan's introduction to Richard Owen's Hunterian Lectures. Green's Hunterian Lecture for the previous year, 1827, expressed these same “evolutionary” ideas in virtually the same terms. See n. 24 of this chapter for the representative quotation. In his Hunterian Lecture of 1840, Green credited Hunter with first formulating the principle of recapitulation—see n. 3, chap. 3, above. Green met the principle, however, also in the work of many of the German authors he knew intimately, particularly Tiedemann and Carus. In his Lehrbook der Zootomie, which Green used as a textbook, Carus not only advanced a cautious recapitulation theory (see nn. 8 and 77, chap. 3, above) but also maintained that the “evolution of nature [Natur in ihrer Entwicklung]” indicates a unity in the animal kingdom, namely, that constituted by “the Idea of Animality, which has its highest expression in the human organism.” See Carl Gustav Carus, Lehrbuch der Zootomie (Leipzig: Gerhard Fleischer the Younger, 1818), p. 6.

(23.) I have no direct evidence that Lyell was familiar with Green's work; but just like Green, Lyell also characterized Lamarck's ideas as a “fancied evolution” (see text to n. 8 in this chapter), which is at least mildly indicative of an intellectual connection. Further, Green, in his “Recapitulatory Lecture” (p. 122), expressly considered, as did Lyell, Tiedemann's evolutionary theory: “If the facts in question were evidence less decisive of a process of development, the deficiency would be abundantly supplied by the curious researches of Tiedemann, on the formation of the foetal brain (Bildungsgeschichte des Gehirns). In tracing the evolution of the brain, he has satisfactorily shown the correspondence of the temporary stages of its construction in the foetus to the permanent forms of the organ characterizing the inferior classes.”

(24.) Green, “Recapitulatory Lecture,” pp. 108–9. This lecture repeated in almost identical terms the evolutionary perspective he developed in his 1827 lectures on the “Natural History of Birds.” In that earlier presentation he reminded his audience that “we have…set out upon the plan of considering nature as a series of evolutions, from the lower, from the lowest form in which Life manifests its power in a production of animated being up to its most complex forms—& I presented to you this view not under the idea that the lower had any power of assuming the rank and privileges of the higher nor upon any such fanciful scheme as that which that otherwise most meritorious naturalist Lamarck has proposed for the invertebrated series of animals, but as the lower passing by a series of evolutions to the higher, under the law & influence of a higher power acting in and by nature.” See Sloan's transcription of Green's “Introductory Lecture to the Natural History of the Birds, 1827,” included as an appendix to his Richard Owen's Hunterian Lectures.

(25.) Desmond makes a wonderfully contextualized case for deeply held political motives determining the scientific debate over evolutionary theory prior to Darwin's Origin of Species. My principal complaint, which touches the heart of his thesis, concerns his insistence that political motives always crawl just beneath the covers of a scientific proposition. While scientific theories—or historiographic ones for that matter—may be moved principally by the lower life of political partisanship, they may have other stimulating causes, for instance, reason and evidence, which may be embedded in scientific tradition, philosophical conviction, or religious belief. The movement under the spread need not always be politics; sometimes scientific desires resonate to their own particular loves. For Desmond's analysis of Green's motivation, see The Politics of Evolution, pp. 260–75.

(26.) Green, “Recapitulatory Lecture,” p. 108.

(27.) Ibid., p. 109.

(28.) See nn. 22 and 23, above.

(29.) See Richards, Darwin and the Emergence of Evolutionary Theories of Mind and Behavior, pp. 247–60; and also n. 20, above.

(30.) See Mill's essay on Coleridge, in John Stuart Mill, On Bentham and Coleridge, introduction by F. R. Leavis (New York: Harper Torch, 1962).

(31.) See nn. 17, 21, and 23, above. While Lyell was composing the second volume of his Principles, which contained his analysis of Lamarck, he was simultaneously pursuing a professorship at Kings College, London (1831), where Green was the Hunterian professor. See Wilson, Charles Lyell, pp. 308–28, for a discussion of Lyell's efforts to secure a professorship.

(32.) Lyell, Principles of Geology, 2: 62–64. Lyell uses the term “evolution” to refer to both Lamarck's theory of species transmutation (p. 60) and Tiedemann's thesis that during gestation the brain of higher creatures “evolved” through stages of the lower (p. 63).

(33.) For historical analyses of Darwin's first formulations of ideas of species change, see Sandra Herbert's introduction to The Red Notebook of Charles Darwin, ed. Sandra Herbert (Ithaca: Cornell University Press, 1980), pp. 11–12; Frank Sulloway, “Darwin's Conversion: The Beagle Voyage and Its After-math,” Journal of the History of Biology 15 (1982): 325–96; and M. J. S. Hodge, “Darwin and the Laws of the Animate Part of the Terrestrial System (1835–1837),” Studies in the History of Biology 6 (1983): 1–106.

(34.) Darwin, Autobiography, p. 120.

(35.) For analyses of the stages of Darwin's intellectual development, see David Kohn, “Theories to Work by: Rejected Theories, Reproduction, and Darwin's Path to Natural Selection,” Studies in the History of Biology 4 (1980): 67–170; M. J. S. Hodge, “Darwin and the Laws of the Animate Part of the Terrestrial System,” and “Darwin as a Lifelong Generation Theorist,” The Darwinian Heritage, ed. David Kohn (Princeton: Princeton University Press, 1985); and Richards, Darwin and the Emergence of Evolutionary Theories of Mind and Behavior, pp. 83–105.

(36.) Darwin's initial reflections on species change are recorded in his “Red Notebook,” MS pp. 127–30, and “Notebook B,” MS pp. 1–23. These and his other early notebooks have been meticulously transcribed and edited in Charles Darwin's Notebooks, 1836–44, ed. Paul Barrett, Peter Gautrey, Sandra Herbert, David Kohn, and Sydney Smith (Ithaca: Cornell University Press, 1987). The cited references come from pp. 61–62 and 170–76 of the Barrett et al. edition.

(37.) Darwin, “Notebook B,” MS pp. 25–39 (Barrett et al., pp. 177–81).

(38.) Darwin, “Notebook B,” MS pp. 63–64 (Barrett et al., p. 187).

(39.) Darwin, “Notebook B,” MS p. 49 (Barrett et al., p. 182).

(40.) Darwin, “Notebook C,” MS p. 171 (Barrett et al., p. 292). Single wedge quotes indicate Darwin's deletions; double wedge quotes indicate his insertions—the standard convention that will be used from here on out.

(41.) See Richards, Darwin and the Emergence of Evolutionary Theories of Mind and Behavior, pp. 85–98.

(42.) Darwin, “Notebook D,” MS pp. 134e–35e (Barrett et al., pp. 374–75). See n. 40.

(43.) In the Origin, Darwin listed use and disuse among the sources of variation for selection. He said: “From the facts alluded to in the first chapter, I think there can be little doubt that use in our domestic animals strengthens and enlarges certain parts, and disuse diminishes them; and that such modifications are inherited.” See Charles Darwin, On the Origin of Species (London: Murray, 1859), p. 134. He also asserted that acquired habit, like selection, could act more immediately to introduce adaptations; but he yet thought his primary device would always retain the upper hand (ibid., pp. 142–43): “On the whole, I think we may conclude that habit, use, and disuse, have, in some cases, played a considerable part in the modification of the constitution, and of the structure of various organs; but that the effects of use and disuse have often been largely combined with, and sometimes overmastered by, the natural selection of innate differences.”

(44.) Stephen Jay Gould, “Eternal Metaphors of Palaeontology,” Patterns of Evolution as Illustrated in the Fossil Record, ed. A. Hallan (New York: Elsevier, 1977), p. 13.

(45.) Charles Darwin to Alpheus Hyatt (4 December 1872), More Letters of Charles Darwin, ed. Francis Darwin (London: Murray, 1903), 1: p. 344; see similar remarks in Darwin's “Essay of 1842,” transcribed in The Foundations of the Origin of Species: Two Essays Written in 1842 and 1844 by Charles Darwin, ed. Francis Darwin (Cambridge: Cambridge University press, 1909), p. 47.

(46.) Stephen Jay Gould, Ever Since Darwin (New York: Norton, 1977), p. 45.

(47.) Darwin, “Notebook B,” MS pp. 5, 16, 18, 20 (Barrett et al., pp. 171, 175).

(48.) I have analyzed Darwin's use of natural selection as a vehicle of biological progress in Robert J. Richards, “The Moral Foundations of the Idea of Evolutionary Progress: Darwin, Spencer, and the Neo-Darwinians,” Evolutionary Progress, ed. Matthew Nitecki (Chicago: University of Chicago Press, 1988). See Hodge, “Darwin and the Laws of the Animate Part of the Terrestrial System,” for a complementary analysis.

(49.) Darwin, “Notebook E,” MS p. 95 (Barrett et al., pp. 422–23).

(50.) Darwin, Origin of Species, p. 118. Darwin made the idea of a heritable tendency to vary a part of his more general theory of divergence. He believed that the theory of divergence, which he slowly formulated during the years 1854–57, was crucial for explaining the branching character of evolutionary descent. After all, evolution could have proceeded linearly. In a biologically shifting environment, in which new niches were always opening up, individuals that had a tendency to vary would have the most advantage—hence groups would gradually become more ramified. Darwin described his theory of divergence in the Origin, pp. 111–26. For historical analyses of his theory, see Dov Ospovat, The Development of Darwin's Theory (Cambridge: Harvard University Press, 1981), pp. 170–83; and David Kohn, “Darwin's Principle of Divergence as Internal Dialogue,” Darwinian Heritage, pp. 245–58.

(51.) Darwin, Origin of Species, p. 106.

(52.) Ibid., p. 337.

(53.) Ibid., p. 83.

(54.) Ibid., p. 489.