I’M A JEWISH ATHEIST. You might think this a weird way to begin a book review, especially one about two books of popular science. But each of the books itself includes a profession of faith. J. Scott Turner, a physiologist at the SUNY College of Environmental Science and Forestry, puts his parenthetically in the preface to Purpose and Desire: What Makes Something “Alive” and Why Modern Darwinism Has Failed to Explain It (2017): “(I’m a Christian, if that matters, albeit not a very good one.)” [1] Richard O. Prum, an evolutionary ornithologist at Yale, ends the introduction to The Evolution of Beauty: How Darwin’s Forgotten Theory of Mate Choice Shapes the Animal World — and Us (2017) by defending himself against the charge of “nihilism.” [2] “How weird,” I thought, which seemed a good point of departure.

Turner explains that he mentions being a Christian because of a review of his earlier book, The Tinkerer’s Accomplice: How Design Emerges from Life Itself (2007), that clearly still rankles. The review, by “a fellow scientist of some renown,” had accused Turner of inappropriately hiding his religious beliefs. “This struck me as strange,” Turner writes, “even a tad illiberal. Would he have demanded a confession from an author whose views he had found more congenial?” [3] No doubt some readers could have remained on the straight and narrow, untempted by gossip; not this one. A guilty foray into Web of Science soon produced a piece by the Oxford biochemist and geneticist Jonathan Hodgkin, who did indeed write of Turner that “if he wants to write this kind of book, he should be more explicit about his own religious beliefs.” [4] Now, just what was it that made Hodgkin doubt Turner’s bona fides as an “orthodox Darwinian” and accuse him of writing “like a deist”? Did Turner, for instance, find evidence for the existence of a rational God in the appearance of design in nature? No, God didn’t come into it. Turner’s “deistic” transgression against Darwinism was to ascribe intentionality not to any divine being but to living organisms.

Specifically, Turner identifies homeostasis — the living organism’s ability to maintain a stable inner environment in response to a changeful outer environment — as the “Second Law of Biology” after natural selection. This idea, that the active maintenance of a stable inner environment is the defining condition of life, belongs originally to the 19th-century French physiologist Claude Bernard, who is Turner’s main hero. In Purpose and Desire, Turner pursues his argument that homeostasis demands “at least rudimentary forms of cognition and intentionality,” the ability to recognize and purposefully respond to environmental conditions. [5] Modern Darwinist biology, Turner says, treats the intentionality of living things as merely apparent, a figment, and either ignores it or tries to explain it away. Turner argues that this is a mistake: living agency is not only real, but it is also the defining feature of life and a driving force in evolution. A science that ignores or tries to explain around intentionality is condemning itself to failure. [6]

So, Hodgkin grew suspicious of Turner’s Darwinism because he ascribed intentional agency to living organisms. Curiouser and curiouser. Not only did Darwin himself do the same in everything he wrote, but in doing so, he had the opposite of deistic intentions. Indeed, we might as well go ahead and call them anti-deistic. Darwin and other early evolutionists re-assigned responsibility for shaping living forms from a divine creator to, among other things, the agency of living organisms. In Darwin’s version of Darwinism, natural selection played a key role, but so too did various living agencies, notably one that Darwin called “use and disuse” (using or failing to use a limb or organ, which, he assumed, would have heritable effects) and another that he named “sexual selection.” The latter is the subject of The Evolution of Beauty, which brings me to Prum. It turns out that Prum, too, was put on the metaphorical rack, not by any church inquisitor, but by “a fellow evolutionary biologist over lunch” at “an American university.” (No Web of Science could help with this one, so I leave the reader to speculate.) What had Prum said to alarm his lunch companion? Had he alleged that God was dead, or that life was a tale told by an idiot, full of sound and fury, signifying nothing? No, according to Prum, he had been expounding his theory of “aesthetic evolution”: “[E]volutionary processes that are driven by the sensory judgments and cognitive choices of individual organisms.” [7]

To summarize: In evolutionary biology today, suggesting that living organisms exercise forms of agency such as those mentioned above is so heterodox as to bring down both insinuations of creationism and charges of nihilism. Even stranger: The insinuations of creationism are against a book invoking no divine agencies but only mortal ones; and the charge of nihilism is against a theory dwelling not in the emptiness of life but in its aesthetic and cognitive richness. How could the same idea, that living organisms have evolutionary agency, which seems incompatible with both creationism and nihilism (which are in turn incompatible with one another), expose people to charges of both? I do have an answer to propose, which I withhold for the moment, but here’s a teaser: my answer resides not in logic but in the ironies of history.

History plays a key role in each book. Turner and Prum both present revisionist evolutionary theories ascribing various forms of agency to the evolving organism, and they rest these theories partly on histories of evolutionary biology, explaining when and how they think it became sacrilegious to make such ascriptions. But while their biological ideas are revisionist, their historical ideas are quite traditional, drawn principally from biology’s disciplinary story about itself. For me, a fellow revisionist but on the historical side of things, this made for a curious reading experience, alternately satisfying and maddening.

Episode Umpteen: The Organism Strikes Back 

Turner’s historical observations, in particular, turn me into something like a frustrated Looney Tunes character: I can feel the smoke fuming from my ears. Of Georges Cuvier, a devout Lutheran who categorically rejected the possibility of the transformation of living forms, Turner writes, “[o]f course Cuvier was an evolutionist.” Wait, what? Turner goes on to explain that Cuvier believed “species changed through time.” [8] That’s an odd way to put it: Cuvier was firmly committed to the fixity of species but he did believe in extinctions. He understood the fossils of extinct creatures to reflect not transformation, but rather a series of catastrophes (such as the Great Flood), each eliminating the creatures of a given time and place, to be replaced later by brand-new, equally fixed and unchanging creatures. By finding evidence of extinctions, Cuvier lent empirical support to the doctrine of special creation, that God had created each species for its niche in nature and had replenished the supply of creatures following each catastrophe (such as the Great Flood) by new acts of creation. Turner likens Cuvier’s successive extinctions and acts of divine creation to Stephen Jay Gould’s theory of “punctuated equilibrium,” affectionately known among biologists and fellow travelers as “punk eke,” with bursts of rapid speciation separated by long periods of comparative stability.

Gould, who died in 2002, was my undergraduate thesis advisor, and I’ve tried to imagine how he might have reacted to this comparison. He did praise Cuvier for reading strata as faithfully as he did Scripture, discerning a discontinuous fossil record and integrating geology and theology into a single empirical research program. [9] But, in addition to being a paleontologist and steadfast opponent of modern, fundamentalist creationism, Gould was also a historian, scrupulous about situating people in time and place. Accordingly, he emphasized that Cuvier found evidence in his carefully sifted evidence for divine creation, not evolution.

Turner sees biology as having sold its soul at the beginning of the 20th century by abandoning “vitalism” for mechanism and materialism. With meaning and purpose stripped away, biology has become all about “cogs and gears.” [10] Nietzsche gets a lot of blame for these grim developments: “[o]nce Friedrich Nietzsche declared in 1882 that God was dead,” Turner writes, “something had to fill the gap, and scientists came rushing in,” [11] presumably brandishing cogs and gears. Turner calls for a re-enchantment of biology, by which he means a return to the approach of 18th- and early 19th-century vitalists. [12] One of his examples is the French naturalist Jean-Baptiste Lamarck, coiner of the term “biology” and author of the first developed theory of the transformation of living forms, or what we now call “evolution.” Lamarck, Turner says, despite his “quaint” notions about “vital essences” and forces, arrived at something approaching a right idea when he divined that such forces could act over generations to shape lineages of organisms. [13] But Turner’s primary example is Claude Bernard, who, Turner says, combined rationalism and Romanticism in developing his holistic view of organisms and their continual, active engagement with their environments. [14]

This is a familiar rendition of the history of science: once upon a time, there were Romantics who said beautiful and profound if not quite modern-scientific things about nature, life, and soul. Then there followed a disenchanted, secular age in which modern science took over the role of supplying meaning, offering it up in the form of cold, hard rationalism. But let’s begin with the Romantics. What does it actually mean to call Lamarck a “vitalist”? Turner never defines the term, and Lamarck himself never used it. Indeed, he might not have recognized it, since it came into common usage only in the decades following his death. [15] “Vitalism” is also, like many words, slippery: the earliest usages mostly took it to be a form of materialism (often condemning it for that reason), whereas many later writers —including Turner — have assumed that the two were opposites. [16] In Lamarck’s case, while he did invoke a “power of life” by which living beings strove toward greater complexity, he meant a material quality characterizing living matter, akin to the forces of contemporary physics: light, heat, electricity, magnetism. There were no immaterial forces, causes, or essences in Lamarck’s science. In fact, early occurrences of the word “vitalist” suggest that vitalism smelled strongly of irreligion. For instance, one scandalized reviewer of an early vitalist work wrote: “[T]he dogmatic vitalist, ashamed of the immense extent of [his] ignorance, and too lazy to await the revelations of nature, turns away from the true worship, and pours forth his confession of faith in vitalism — the golden calf of his own imagination.” [17]

Lamarck also proposed that organisms, by responding to their environments, could transform themselves in tiny but incremental and heritable ways, an idea that Darwin took up as “use and disuse” and that later came to be known as “the inheritance of acquired characteristics.” Whether this and Lamarck’s “power of life” idea make him a vitalist depends on what you mean by “vitalist,” but both were fully material processes. In addition to cleaving to materialist explanations, Lamarck was also a mechanist, or so he represented himself. He described living beings as “animate machines.” [18] He used the words “mechanism,” “mechanical,” and “machine” constantly; on the rare occasions when he used the word “soul,” it was to insist on a fully “material soul,” which he identified as the physical phenomenon of heat. In fact, Lamarck pronounced any “immaterial soul” as “baseless and purely imaginary.” [19] “Vitalist” science, in other words, did not imply “enchanted” or “ensouled” science, but just the opposite: materialism, mechanism, naturalism.

Claude Bernard, Turner’s touchstone “vitalist,” explicitly rejected “vitalism” (as Turner acknowledges), finding the notion of a special vital force or tendency to be “antiscientific.” Like Lamarck, Bernard insisted that “an organism is nothing but a living machine.” Its distinctness, he said, resided not in any vital principle but in an organism’s special mode of functioning, directed by a governing “idea.” [20] Bernard also had a reputation for atheism, which he courted for instance by rejecting the Cartesian idea of an immaterial soul responsible for thought: “[T]he brain is the organ of intelligence,” he wrote unequivocally, “in the same way that the heart is the organ of circulation and the larynx the organ of the voice.” [21]

The core theme of Romantic literary and philosophical writing that both Lamarck and Bernard developed in their science was about not enchantment or soul but the material interconnectedness of all things in nature, and the integration of humans into the cosmic continuum. The living organism, Bernard wrote, “takes part in the universal concert of things, and the life of the animal, for example, is only a fragment of the total life of the universe.” [22] Nietzsche, announcing the death of God, was not defeating this Romantic tradition but carrying it forward. With God taken care of, Nietzsche goes on to demand, “[w]hen may we begin to ‘naturalize’ humanity?” [23] He admired Claude Bernard — his physiological ideas and his heroic model of scientific genius — and even came to defend vivisection, a practice of which Bernard was a leading advocate, and over which Nietzsche broke with his erstwhile friend, the anti-vivisectionist composer Richard Wagner. [24] Nietzsche rejoiced that “physiology and the history of animals” had at last begun to reveal the nature of consciousness, and like Bernard, he asserted that a kind of thinking was essential to living: “Man, like every living being, thinks continually without knowing it.” [25]

Finally, let’s consider biologists’ widespread move at the turn of the 20th century away from Lamarck’s and Bernard’s active, holistic approach toward a narrow, proximate, push-me-pull-you sort of mechanical explanation. This was not biology losing or abandoning or selling its soul, as Turner says, but outsourcing it. Around the turn of the 20th century, primarily in the new German research universities, the science faculties entered into a tacit limited partnership arrangement with theology faculties whereby biologists would treat the passive mechanisms of living things, leaving the formative agencies to the theologians. [26] In describing living things as passive mechanical artifacts, biologists drew upon a natural-theological tradition that had originated in the 17th century and reached a pinnacle around the turn of the 19th in the work of the English theologian William Paley. This was the argument from design: finding evidence for the existence of a divine Clockmaker in the artifactual perfection of nature, especially living beings. Naturalists first developed a notion of “fitness” or “adaptation,” consisting of the myriad ways in which living beings are suited to their environments, in seeking ever more refined arguments from design. Darwin recalled having memorized passages of Paley’s writing as a student at Cambridge, and he incorporated elements of Paley’s notion of adaptation into his theory of evolution. This history prepared a basis on which biology and theology could coexist comfortably, so long as biologists stuck to describing living things as fundamentally passive mechanical artifacts.

A key figure in the development of this new approach was August Weismann, the primary author of the neo-Darwinist interpretation of Darwinism around the turn of the 20th century. Weismann’s interpretation of Darwinism imposed a barrier, the so-called “Weismann barrier,” between somatic (body) cells and germ (reproductive) cells, such that no bodily change in the lifetime of an individual organism could be inherited. In other words, Weismann ruled out the inheritance of acquired characteristics along with every other sort of internal formative agency, rendering organisms utterly passive with regard to evolutionary development. Turner writes that Weismann arrived at his view on a “hunch” [27] — but it was more than a hunch. It was an article of faith. As Weismann himself maintained, his approach to science was “absolutely opposed to that of the materialist.” He believed in a teleological “Final Cause” or “Universal Cause” operating “behind” the mechanism of the universe, holding a monopoly on creative agency. [28]

To repeat, it wasn’t a loss of religion (or soul or enchantment) that turned biology from Lamarck’s and Bernard’s approach, in which living beings actively shaped themselves in response to their environments, to Weismann’s world of passive artifact-beings. On the contrary, it was a reconciliation with religion: a turn from the rigorously naturalizing, essentially materialist tradition of Enlightenment and Romantic naturalists toward a theologically infused Anglo-German tradition shaped crucially by Paley and the argument from design. Scientists generally see the history of science as a progressive eradication of the nonrational — superstition, mysticism, religion — and Turner is no exception, though he laments what he takes to be a loss of soul and enchantment. But he has the historical trajectory backward: if he wants to restore something like the science of the late 18th- and early 19th-century naturalists — those he calls “vitalists,” authors of the ideas of evolution and homeostasis — he shouldn’t be calling for a re-enchantment of biology. What Turner should be seeking is a more complete and thorough disenchantment: not an ensoulment but a decisive elimination of soul, at least the metaphysical variety, and a reinfusion of purposeful agency into material nature. That’s what would be required to return to the active, dynamic, holistic, and essentially material world of Romantic science.

Indeed, Turner himself represents such a return, both in his science and his writing. Consider how he describes homeostasis. It is, he tells us, a form of purposeful responsiveness prerequisite to life; the defining qualities of living things are therefore “purpose and desire” in response to a wider world. Assuming that homeostasis had to exist before there could be life, Turner proposes that life originated from the top down rather than the bottom up, as a persistent system of energy, an “order-producing thermodynamic system.” He describes it as a ramification of the continual energetic tidal wave traveling from Sun to Earth,

a complex cascade of energy: a turbulent, frothy wave of electrons interposed between the sun and the rest of the universe. The wave crests first at the interception of light by green plants, tumbles down the curl through animals and ends with the bubbly foam of the decomposer bacteria and fungi. […] This foamy wave of energy is a standing wave. […] Life, therefore, represents a tiny froth on the crest of the Earth’s standing wave of orderliness.

Turner concludes that life emerged “as a massive extended — an intentional — organism.” [29]

Could there be a more quintessentially Romantic idea or image? Here’s Wordsworth: “A motion and a spirit, that impels / All thinking things, all objects of all thought, / And rolls through all things.” [30] And Johann Gottfried Herder: “Be it, that we know nothing of our soul as pure spirit: we desire not to know it as such. Be it, that it acts only as an organic power: it was not intended to act otherwise.” Our own “machine,” Herder observed, is “a growing, flourishing tree,” and so it “feels even with trees; and there are men, who cannot bear to see a young tree cut down or destroyed.” [31] Similarly, according to Erasmus Darwin, Charles’s Romantic grandfather, Mind characterized all Life: even flowers could entertain “ideas” and “passions.” [32] Turner may be a not-very-good Christian in his personal life, but with regard to his science, he’s a quite good neo-Romantic.

It’s not just a matter of historical exactitude to specify that Turner’s science represents neo-Romanticism, not Christian re-enchantment or ensoulment. History matters. It’s important because Turner’s purpose is to bring about an intellectual and cultural change in biology, and to do that, you first need to understand the forces shaping the intellectual culture you want to influence. Turner identifies a crisis of alienation in which the science of evolution has played a crucial role: “[T]he alienation of the science of life from life itself, but more alarmingly, of science from the broader culture.” [33] To be sure, yes, but this alienation did not arise from a loss of soul. Rather, it arose from outsourcing the soul: from the strict limitations on science imposed by its relations to theology around the turn of the 20th century. In the same period, the sciences diverged from the humanities at every level — institutional, methodological, stylistic, substantive — as scientists did indeed largely renounce discussions of meaning and purpose. In so doing, they weren’t celebrating the death of God; they were granting Him a monopoly on agency. In this sense, they far surpassed in deference even the medieval Catholics, whose God presided over a cosmos permeated by agencies of many kinds.

Turner provocatively laments “the shabby treatment that has been meted out to various advocates of and sympathizers to intelligent design theory, even to academicians with long-standing solid reputations who suggest there is a legitimate critique to be made of Darwinism, at least in its modern form.” [34] I rushed to his footnote to see just which intelligent design theorists with solid academic reputations he had in mind, but I didn’t find any. There was only one book, Thomas Nagel’s Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False. This book caused a small firestorm following its publication in 2012 because, like Turner, Nagel appears to flirt with creationism, but also like Turner, Nagel’s not a creationist. He carefully announces in his introduction — another profession of faith! — that he sees no divine purpose in nature and invokes no transcendent being. He advocates for what he calls “teleological naturalism” — or sometimes “naturalistic teleology” — which amounts to acknowledging a direction in nature, a tendency governing the “self-organization of matter,” and incorporating this acknowledgment into science. “My preference for an immanent, natural explanation [of consciousness, action, cognition],” Nagel writes, “is congruent with my atheism.” [35] That Turner’s and Nagel’s theories give off a contradictory whiff of creationism, even to their own noses, is evidence of the historical confusion I’ve been tracing.

Episode Umpty-Umpth: Return of the Bird’s Eye

Reinvesting the passive, mechanical artifact-organisms of neo-Darwinism with agency is also Prum’s central purpose. In his case, it is the agency of sexually reproducing animals to exercise their own aesthetic criteria in choosing their mates, the phenomenon that Darwin named “sexual selection.” Darwin’s paradigm example was the male peacock’s tail, which he lamented had “often been thrown in my teeth” as a structure so intricately beautiful it could only have been designed by God. [36] The idea of sexual selection provided Darwin with an alternative designing force: many generations of discerning peahens. But even in Darwin’s day, and even among proponents of evolution, Darwin’s claim was controversial. Many objected that sexual selection was simply an aspect or part of natural selection: certain traits arose because they reflected general fitness (strength, agility, or whatever adaptive features benefited the animal), and individuals displaying these traits had the additional selective advantage that prospective mates could tell just how fit they were. This “honest signaling” has been the mainstream theory for a century and a half, Prum says, but he disagrees: he sees sexual selection, or what he calls “aesthetic evolution,” as an independent and irreducible force in shaping evolutionary development. [37]

In Prum’s view, animals act upon their own aesthetic sensibilities to shape the evolution of biodiversity. To prove his point, he takes the reader on a guided tour through the art scenes of various species of birds. In their “leks,” territories in which groupings of males engage in mating displays, male manakins perform elaborately composed and choreographed songs and dances, often collaboratively. [38] Male bowerbirds build sophisticated structures of varying sizes, colors, and architectural designs for the sole purpose of attracting mates. The satin bowerbird insists upon only royal blue objects for his bower; the golden bowerbird’s structure consists of two connected, towering maypoles; the vogelkop bowerbird’s bower looks a bit like a side-view of Eero Saarinen’s TWA terminal; and the great bowerbird of eastern Queensland arranges objects of increasing size at increasing distances outside his bower to create a forced-perspective illusion, flattening the landscape for the female looking out. [39]

Despite such displays of deliberate artistry, mainstream evolutionary biology has denied agency to organisms, Prum says, and like Turner he attributes this to an excess of cold, hard rationalism. He reckons the startled lunch companion who accused him of nihilism must have been distraught at the idea that, if animal aesthetic judgments can drive evolution, the universe can’t be fully rational. [40] This is, once again, how scientists traditionally represent the history of science: as the inexorable forward march of rationalism, eradicating all traces of the nonrational. Prum, like Turner, regrets it, but he doesn’t question it. But this view of the history of evolutionary biology is fundamentally mistaken. As we’ve seen, between the turn of the 19th and turn of the 20th centuries, mainstream biology became more, not less, deferential to — and indeed cooperative with — a tradition of Christian theology, the argument from design. Scientific rationalism and Christian faith were not opposing forces in this development but partners: the growing commitment on the part of biologists such as Weismann to a narrow, proximate, mechanist form of rationalism was itself an expression of faith in a supernatural power — or at the very least, a form of political and cultural deference to the claims of such faith. Likewise, sexual selection lost favor almost as soon as Darwin proposed it, not because of his contemporaries’ fierce devotion to rationality, but rather because of their deference to a divine monopoly on creative agency.

Take Prum’s first culprit, Alfred Russel Wallace, a sort of parallel inventor to Darwin of the theory of evolution by natural selection, having arrived independently and concurrently at an essentially similar idea. Prum identifies Wallace as the original author of the “honest signaling” argument against sexual selection. [41] Darwin and Wallace had a long, fraught friendship. They warmly collaborated as allies in defending “our position,” [42] and yet they came to have a profound disagreement in just the area Darwin believed most crucial to defend: the theory’s sufficiency without recourse to a designer god. Darwin sought rigorously naturalist explanations throughout his career, and he became ever more skeptical of religion. In 1860, he wrote to his friend, the Harvard botanist Asa Gray, that he couldn’t believe in divine design because there was just “too much misery in the world.” [43]

Wallace initially agreed with Darwin that evolution could account for all aspects of life, even human life, and said so in an article for Anthropological Review in 1864. [44] But five years later, he had moved sharply away from that view. He published a discussion of natural selection in which he removed human beings from the theory’s purview, concluding that humans could only be the product of a divine creator (and the following year, further inferring that all forces in nature originated in the will of a “Supreme Intelligence”). [45] Darwin was dismayed at losing Wallace as a comrade against those he referred to as “Paley and Co.” [46] He wrote Wallace a letter full of kindness and compliments, calling his explanation of their theory “inimitably good; there never lived a better expounder than you.” Regarding the “remarks on Man,” however, he wrote sorrowfully, “[i]f you had not told me I shd have thought that they had been added by some one else. As you expected I differ grievously from you, & I am very sorry for it. I can see no necessity for calling in an additional & proximate cause in regard to Man.” [47] The next year, in response to Wallace’s further publication of his new views, Darwin continued to lament, softening his regret with humor: “I groan over Man — you write like a metamorphosed (in retrograde direction) naturalist, & you the author of the best paper that ever appeared in Anth. Review! Eheu Eheu Eheu / Your miserable friend / C. Darwin.” [48]

Around the same time that Wallace changed his mind about the importance of a “Supreme Intelligence,” he also changed his mind about sexual selection, and for the same reason. Natural selection, as Wallace saw it, worked unerringly to enhance “utility,” [49] and could easily serve as an instrument of divine design. In contrast, Darwin’s sexual selection, allowing animals to act upon their own preferences, appeared to usurp the divine monopoly on creative agency that Wallace saw expressed through natural selection. “Male rivalry” — the competition of male animals for mates — was a legitimate selective force, Wallace allowed, since it was in fact a form of natural selection. But the “action of female choice or preference” was not: it had “none of that character of constancy and of inevitable result that attaches to natural selection.” [50] Darwin was again distressed at his friend’s change. “I grieve to differ from you,” he wrote, “& it actually terrifies me & makes me constantly distrust myself. — I fear we shall never quite understand each other.” [51] Almost a decade later, Darwin remained humorously reproachful: “P.S. I am very sorry that you have given up Sexual Selection. — I am not at all shaken & stick to my colours like a true Briton. When I think about the unadorned head of the Argus pheasant, I might exclaim, ‘et tu Brute’!” [52]

Wallace’s rejection of sexual selection went along with his abandonment of rigorous naturalism. To insist on natural selection as the only shaping force in living beings was equivalent to maintaining the monopoly of the “Supreme Intelligence” on creative agency. Wallace purged Darwinism of sexual selection, offering the result as “pure Darwinism,” [53] for the same reason that Weismann purged Darwinism of Lamarckian inner agencies. Both Wallace and Weismann believed that a respectable Darwinism for the 20th century must be one deferential to God’s creative monopoly, devoid of any competing agency.

Prum cites another early critic who charged Darwin with having abandoned true Darwinism in advancing his theory of sexual selection, the heterodox Catholic biologist St. George Mivart. Like Wallace, Mivart professed a limited belief in evolution, exempting the human mind as the work of a divine creator, and he saw natural selection as acting “in obedience to a creative fiat originally imposed on the primeval Cosmos, ‘in the beginning,’ by its Creator, its Upholder, and its Lord.” [54] No animal, acting on whatever whimsical bestial preferences an animal might exhibit, could possibly interfere in the Lord’s creative fiat. Accordingly, Mivart wrote that sexual selection — apart from male combat, which like Wallace he took to be “a kind of ‘natural selection,’” and as such, carrying out the divine plan — was not “a vera causa.” [55]

So, the long-established tradition in evolutionary biology that Prum identifies, in which biologists have rejected sexual selection by arguing that it is simply an expression of natural selection, originated not in rationalism but in Christian faith; or rather, in a variety of rationalism, the reductive kind that casts nature as working ever and unerringly to increase “utility,” that was an expression of Christian faith. Initially, those who insisted upon natural selection as the solitary force shaping the development of living forms, and upon the absolute passivity of organisms, were affirming God’s creative monopoly and the perfection of His creation.

By the middle decades of the 20th century, this insistence had become a kind of loyalty oath among evolutionary biologists. But here things get complicated. The heirs to this neo-Darwinist tradition, who have mostly remained categorical in their adherence to natural-selection-only and so to excluding any evolutionary agency on the part of organisms, are not proselytizers for any form of Christianity, but often indeed for atheism: people such as the Oxford evolutionary biologist and popular science writer Richard Dawkins. While they don’t believe in God, these biologists have retained certain foundational elements of Wallace’s and Weismann’s theology. [56] For example, as the instrument of divine purpose, natural selection had to be unitary and unremitting in its action, always working to increase perfection. [57] Also, as the vector of God’s will, natural selection had to be the sole source of reason and meaning; any interloping force such as sexual selection must be “arbitrary” and “meaningless.” [58] Neo-Darwinists, while eventually eliminating God from their picture, have continued to represent natural selection as unitary and unremitting, [59] and all other possible agencies, such as sexual selection, as arbitrary and meaningless. [60] Dawkins’s colleague and former student, the Oxford ethologist and evolutionary biologist Alan Grafen, has, for instance, objected to a particular theory of sexual selection as featuring “arbitrary” factors lacking all “rhyme and reason,” and has even, as Prum notes with amusement, called it methodologically “wicked” [61] — his vocabulary reflecting the forgotten theological origins of his position.

Yet Prum also consistently describes the results of sexual selection as “meaningless and arbitrary.” [62] He doesn’t question the traditional assumption in evolutionary biology of a single axis of meaning or reason in nature. He accepts, too, the extraordinarily narrow definition of reason that has held sway in neo-Darwinist biology. Couldn’t aesthetic judgment be an expression or component of reason? Plenty of philosophers have thought so. Hume argued that in order to form ideas at all, the mind first needed “reflective impressions” to work upon, which it received from two sources: “the sense of beauty” and “the passions.” [63] Kant, who wrote that “the concept of an objective purposiveness of nature is a critical principle of Reason,” also asserted that we apprehend this purposiveness only through aesthetic judgment. [64] You needn’t be a Humean or Kantian to find the utility-maximizing conception of reason awfully limited: outside of neo-Darwinist evolutionary biology, it’s not so easy to find people seriously arguing that aesthetic judgments are irrational.

Except in one other discipline: certain economists have shared this logic with evolutionary biologists, reducing all behavior to a single dimension, the maximization of market value or adaptive fitness respectively. Prum in fact compares neo-Darwinist biologists to efficient-market theorists in their tendency to assume that behavior is rational: animals make mating choices and consumers make purchasing choices based on reasoned assessments of adaptive or market value rather than for “irrational” reasons deriving from passions, desires, and popular influences. [65] But still, he accepts the assumption that utility can be reduced to a single dimension, that every decision either increases or decreases it, and that each one is therefore either rational or irrational. Rather than going for a foundational revisionism — suggesting that reason, meaning, and utility are each irreducibly diverse and complex, and that they include, for example, the exercise of capacities such as aesthetic judgment — Prum seems to offer a shallower sort of revisionism. He affirms the old idea that a trait is either useful or useless, meaningful or meaningless, and simply urges consideration of the “meaningless” ones as products of sexual selection. Even though he rejects the neo-Darwinist tendency to explain all traits as adaptive results of natural selection, he perpetuates the underlying assumption that organisms are reducible to compilations of traits, which are in turn measurable along a single axis of utility.

Indeed, in order to make the case that sexual selection is an autonomous mechanism, not reducible to natural selection, Prum emphasizes that its results are not only useless but sometimes even harmful. The male club-winged manakin, for example, sings his extraordinary song — or plays it — partly by rubbing his feathers together, bowing them like a violin. The structures that make for a good string instrument being presumably different from those that make for a good flying machine, Prum writes that although he can’t prove it yet, he’s sure this is an example of sexual or aesthetic “decadence.” In producing feathers that are good for song, sexual selection has likely damaged the bird’s ability not only to fly but even to survive and reproduce. [66] I think I understand why Prum emphasizes that sexual selection can have results that are non-adaptive and even “decadent,” perhaps leading to the decline or extinction of a species. [67] He sees this as the strongest counterargument to the natural-selection-only position that adaptive changes always necessarily defeat non-adaptive ones and natural selection overwhelms all other mechanisms. So it is, within the old logic of the adaptationist position, a reductive zero-sum-game logic in which gains and losses all occupy a single dimension.

In keeping with the traditional, unitary logic of evolutionary biology, with its assumption of a single common denominator of utility, Prum frequently engages in an either/or kind of reasoning. For example, regarding humans he writes: “[R]egardless of whether the reduction of body hair [in relation to other primates] is an aesthetic trait or not, it’s clear that another unique trait” — the retention of pubic and armpit hair — “is ornamental.” [68] Must it be one thing or the other? This reductive model of organisms as compilations of traits, each one either useful or not, first emerged, as we’ve seen, in conjunction with the theological principle that a divine intelligence designed living things through the mechanism of natural selection. The accompanying reductive logic of neo-Darwinist evolutionary biology is not only originally theological, but also tautologous, as others including Turner have pointed out: [69] natural selection maximizes fitness, and fitness is that which natural selection maximizes. It can’t be false, to be sure, but it’s also of limited use: it says nothing about the possibly irreducible complex of traits and capacities that results in certain forms of life persisting.

Another bit of residual natural theology in neo-Darwinist evolutionary biology is the practice of basing arguments about human society upon theories of evolutionary development. Dawkins again provides an example as a leading proponent of “sociobiology” since the 1970s. [70] Once again, Prum disagrees with Dawkins’s adaptationist arguments and the conclusions he draws from them but still embraces the underlying assumption that evolutionary theory holds direct implications for human society. Dawkins figures in Prum’s story as an extreme partisan of the “honest signaling” argument against sexual selection. He features Dawkins’s memorable explanation of why humans, alone among primates, lack a baculum, or bone, in the penis. Without a baculum, Dawkins reasons, penises can serve as honest indicators to women choosing mates: “[O]nly genuinely healthy or strong males could present a really stiff erection and the females could make an unobstructed diagnosis.” A baculum, however, Dawkins exclaims, “would get in the way! Anybody can grow a bone in the penis; you don’t have to be particularly healthy or tough.” Prum objects to this logic by pointing out that essentially anybody with a penis can have an erection: for men of “mating age,” it doesn’t in fact require one to be “particularly healthy or tough.” He calls Dawkins’s honest signaling explanation “[t]he adolescent male fantasy of erectile omnipotence” transformed into “an explanatory force in human evolution,” and as such, “a masterwork of phallocentric evolutionary biology.” [71]

But phallocentrism is not a distinguishing feature of Dawkins’s reductive selectionism. Prum’s alternative explanation of the human penis is no less phallocentric. Human penises, he says, are “bigger, wider and distinctively shaped” as compared to other primates because that’s how human women like them: turns out, bigger is better. (Reader, you might want to put down your coffee.) Prum goes on to argue that the human penis induces in women an “anticipatory pleasure [that] is then succeeded by the pleasure of experiencing that penis directly during sexual interactions and copulation.” In conclusion, Prum muses fondly, the human penis is “a piece of interactive, personal, tactile sculpture” and a triumph of “genital beauty.” [72]

A surprising proportion of the Evolution of Beauty centers upon penises. There are indeed some remarkably interesting things to be said about them. For instance, certain species of ducks have extremely long, counterclockwise-corkscrew-shaped penises that unfurl explosively during mating. The counterpart duck vaginas, meanwhile, corkscrew in the opposite (clockwise) direction and have trick cul-de-sacs and dead ends. To understand the importance of these details to Prum’s theory, you also have to know that duck sex involves a lot of “forced copulations,” which Prum refers to as “sexual violence” and even suggests one could think of in terms of “rape.” He argues that duck genitalia present an example of coevolution, in this case conflictual coevolution, through sexual selection: “a kind of arms race between males and females” in which each sex has evolved to gain greater control of reproduction. The female ducks are winning: in almost all forced copulations, Prum reports, they manage to avoid fertilization. (This conclusion is based on a series of experiments carried out with his colleague, Patty Brennan, in which they quickly swapped glass models of duck vaginas for actual female ducks at the crucial moment. [73])

“This is a dark evolutionary tale with an amazing and profoundly redemptive outcome,” Prum concludes. Despite “persistent sexual violence,” female ducks have continued to assert their “sexual autonomy,” to exercise reproductive “freedom,” and to pursue their quest for “beauty in their world.” Indeed, Prum calls his duck sex result “a profoundly feminist scientific discovery.” [74] It’s not only ducks — feminist triumphs of sexual autonomy and reproductive choice occur throughout the bird world. Female bowerbirds, Prum writes, have shaped the males’ building of bowers so as produce structures that protect the females from “sexual coercion” [75]; and female manakins have exerted their distaste for aggression and preference for gentle, collaborative males, bringing about the development of leks as “socially cooperative aesthetic gatherings of males” where females can comparison-shop for mates in peace. [76]

Lest readers feel any twinges of concern about where all this bird feminism might lead, Prum is adamant that there is positively no henpecking. “Female sexual autonomy is not a form of female power over males,” he repeatedly assures the reader. Female ducks exert only freedom of choice and not “sexual control over males.” Nor do female bowerbirds have any interest in “wimpy males” that they can “socially or physically dominate.” [77] But I couldn’t help wondering: how do we know that male ducks, manakins, and bowerbirds don’t feel ill-used: emotionally manipulated and driven crazy with collecting royal blue objects and whatnot with no certainty of reward?

Here’s where Prum shares something beyond phallocentrism with Dawkins: a residual, reductive assumption that evolutionary theories provide the foundations for social and political arguments. Why should they? If a divine power has arranged it all, then sure. But if not, what makes duck politics or bowerbird politics, if there is such a thing, relevant to human politics? Prum’s duck sex discovery is “feminist,” he says, because it shows that “[s]exual autonomy is not merely a political idea, a legal concept, or a philosophical theory; rather, it is a natural consequence” of evolution. [78] But why “merely”? Need political ideas, legal concepts, and philosophical theories reduce to natural consequences of evolution to be more than “mere”? Later in the book, Prum returns to the same point: “Sexual autonomy is not a mythical and poorly conceived legal concept invented by feminists and liberals.” [79] But what if it were a legal concept invented by feminists and liberals? Would that make it necessarily mythical and poorly conceived? And if we are to read social and political consequences from Prum’s evolutionary arguments about birds, are they necessarily all redemptive? Should human society be determined by popularity contests, and those whom popular opinion finds less attractive condemned to lead solitary, childless lives?

Prum’s demonstrations of the irreducible importance of sexual selection in bird evolution are fascinating and compelling. But regarding human society and culture, he’s less persuasive. For one thing, he offers a scandalous misreading of Robert McCloskey’s classic 1941 book Make Way for Ducklings. Prum recounts that he was once asked at a dinner party what’s wrong with Mr. Mallard: just as he’s starting a nice family together with Mrs. Mallard, he ups and “takes off!” Prum explained to his scandalized dinner companion that “in many non-territorial waterfowl the male of the pair abandons the female as soon as she begins incubating eggs.” [80] Perhaps so, but not Mr. Mallard. He waited patiently for the ducklings to hatch, an event he witnessed “bursting with pride.” Soon afterward, he did indeed take off — for a week’s trip to survey the Charles River. “‘I’ll meet you in a week, in the Public Garden,’ he quacked over his shoulder,” and when Mrs. Mallard and the ducklings got there, “Mr. Mallard was waiting for them, just as he had promised.” [81] Anyone who can so badly misconstrue a literary classic is hard to trust as a cultural critic.

Then, too, Prum is transparent in projecting familiar social attitudes and preoccupations, not to say clichés, into evolutionary explanations. For example, he writes that whereas certain female traits such as permanent (not only present during lactation) breasts are “ornaments” that emerged because of mating preferences, human males have a relative lack of such ornaments, with one notable exception, as discussed above, the penis. This lack of male ornaments, Prum explains, results from the fact that human females have cared more about “social rather than physical traits” and sought “mates who [would] be good partners to them and good parents to their children.” [82] Here is the same vicious circle long familiar from evolutionary psychology, in which social stereotypes inform scientific theory that then reifies the social stereotypes. Prum also doesn’t say on what basis he judges human females to be better ornamented than human males, other than to cite the field of evolutionary psychology and its findings, also pointing out that (gosh!) there is a much smaller literature on female preferences regarding male ornaments. [83] Here too, Prum’s revisionism is surface-level: he accepts the findings of evolutionary psychology and merely explains them differently, as the results of sexual selection rather than natural selection.

The “deweaponization” of human males — their closeness in size to females, compared with other male primates, and their lack of razor-sharp canines — provides Prum a further example of sexual selection, resulting, he proposes, from female humans’ preferences for non-menacing males, and he once again hastens to assure the reader that such a process “would not result in emasculated, wimpy, or subordinate males.” [84] The same goes for both male and female same-sex behavior: Prum suggests that both evolved through sexual selection to “advance female sexual autonomy” and again reassures the reader: “[T]his hypothesis does not imply that male same-sex behavior evolved through female preferences for weaker, subservient, feminized or emasculated males that females can socially or physically dominate.” [85]

In sum, evolutionary biology reveals a natural order of respectful and collaborative but never wimpy or emasculated men, a world in which women exert their taming influence to make men ever better citizens … and better lovers, too. Prum calls “women’s sexual pleasure” the “most central and enduring mystery about sex. What is its purpose,” he asks rhetorically, “and why does it exist?” The reason for the male orgasm, he explains, has “always seemed obvious”: associated with the ejaculation of sperm, it must have evolved through natural selection as a motivation for men to have lots of sex. Prum then canvasses the long history of variously elaborate and often absurd attempts to explain female orgasm before proposing his own solution: through sexual selection, women have exerted mating preferences for “male traits and behaviors that they find sexually pleasurable.” In fact, because the female orgasm has no other job to do than provide pleasure, Prum speculates that its possibilities are limitless compared to the workaday male orgasm, which is ultimately all about “plumbing.” If you sense another feminist conclusion coming (sorry!), you’re not wrong: “in a delightful and unexpectedly feminist fashion,” Prum writes, it turns out that women are “the active agents in the evolution of their own capacity for orgasmic pleasure.” [86]

Not to keep raining on the feminist parade, but I can’t help questioning the underlying premise, long-established though it may be: Why is women’s sexual pleasure any more mysterious than men’s? I suppose it’s true what Prum says about the plumbing aspect of the male orgasm, but why does it have to feel any better than any other bodily function? Surely, the subjective experience of orgasm for men presents exactly the same “mystery” as for women: neither serves any immediately obvious purpose with regard to reproductive success, other than, presumably, to inspire people to have sex. One could also speculate that physical intimacy, considered quite apart from reproductive sex, carries benefits for people; the capacity to have orgasms might then provide various kinds of selective advantages, and be generally associated with thriving, for males and females alike. In any event, Prum has again accepted the traditional assumption — in this case that women’s sexual pleasure is somehow more “mysterious” than men’s and requires special treatment — before offering his alternative explanation, which seeks and always seems to find a redemptive order in nature.

Herbert Spencer, one of the first to develop and popularize the idea that Darwin’s theory provided a basis for understanding human society (along with everything else), often referred to an “Unknown Power manifested in the Universe.” Rather than seeking to honor this Power “by such titles as ‘The Master-Builder’ or ‘The Great Artificer,’” Spencer wrote, we should realize that it works “after a method quite different from that of human mechanics […] not by manufacture but by evolution.” [87] As we’ve seen, Darwin himself doubted that there was a benevolent, designing power manifesting itself through the natural processes he described. But many of his followers promulgated interpretations of his theory that attached a divine moral authority to it. This natural theology was built deep into the foundations of evolutionary biology, where clearly it still remains.

Here at last is the answer I promised to the question of how the same idea, that living organisms have evolutionary agency, could sound both suspiciously creationist and also dangerously nihilistic to today’s mainstream evolutionary biologists: creationist because it violates a foundational taboo of the discipline, the reasons for which have been long forgotten; and nihilistic because it undermines the single axis of meaning around which the discipline has oriented itself for a century and a half. But in fact, the idea that organisms have evolutionary agency is neither creationist nor nihilistic. It is, rather, an originally Romantic and abidingly radical, rigorously naturalist, scientific approach to the self-making, meaning-making capacity of living things.

¤

Jessica Riskin is a history professor at Stanford University, where she teaches courses in European intellectual and cultural history and the history of science. She is the author, most recently, of The Restless Clock: A History of the Centuries-Long Argument Over What Makes Living Things Tick (2016).

¤

[1] Turner, p. x.

[2] Prum, p. 14; see also p. 148.

[3] Turner, p. x.

[4] Jonathan Hodgkin, “Double Duty,” in the Times Literary Supplement, Issue 5474 (February 29, 2008), p. 30.

[5] Turner, Ch. 2; p. 253.

[6] Turner, 9.

[7] Prum, 14, 8.

[8] Turner, 83.

[9] Gould, Hen’s Teeth and Horse’s Toes: Further Reflections in Natural History (New York: Norton, 1984), Ch. 7.

[10] Turner, xi, 22, 292. On biology’s soul, see also 128–135.

[11] Turner, 46; see also 133.

[12] Turner, 292; see also 185.

[13] Turner, 80–81.

[14] Turner, 98.

[15] On the history of the term “vitalism,” and related words, see Roseleyne Rey, Naissance et développement du vitalisme en France de la deuxième moitié du 18e siècle à la fin du Premier Empire (Oxford, United Kingdom: Voltaire Foundation, 2000); Charles T. Wolfe and Motoichi Terada, “The Animal Economy as Object and Program in Montpellier Vitalism,” Science in Context 21 (2008): 537–579, on pp. 538–543n4; Elizabeth A. Williams, A Cultural History of Medical Vitalism in Enlightenment Montpellier (Burlington, Vermont: Ashgate, 2003).

[16] The first authoritative definition of the term that I can find, in the 1830 volume of a French encyclopedia, defines “vitalist” as “name given to those doctors who explain all the phenomena of life […] by a vital principle.” The rest of the article is devoted to a heated defense of the doctors against an evidently widespread accusation that they were depraved materialists. J. P. Nicholas, “Vitaliste,” in Charles-Joseph Pancoucke, ed., Encyclopédie méthodique, Médecine, 13 (Paris: Agasse, 1830): 474.

[17] “Critical Notices of New Publications,” in The Analyst: A Quarterly Journal of Science, Literature, Natural History and Fine Arts, Vol. 3 (London: Simpkin, Marshall, 1836), 321.

[18] Jean-Baptiste Lamarck, Philosophie zoologique, ou, Exposition des considérations relative à l’histoire naturelle des animaux, two volumes (Paris: Dentu, 1809), 2: 95.

[19] Lamarck, Recherches sur l’organisation des corps vivans (Paris: Chez l’auteur et Maillard, 1802), 102; Philosophie zoologique, 2: 82, 187.

[20] Turner, 25; Claude Bernard, Leçons sur les phénomènes de la vie, communs aux animaux et aux végétaux, 2 vols. (Paris: Baillière, 1878–1879), 1:46, 49; Cahier de notes, 1850–1860, edited by Mirko Dražen Grmek (Paris: Gallimard, 1965), 124; Introduction à l’étude de la médecine expérimentale, 1865 (Paris: Flammarion, 1966), 75 (for “living machine,” see also 64, 78, 87, 90, 94, 180; Bernard, Leçons, 1:293, 316); Leçons, 2:219, Introduction, 90, 94.

[21] Bernard, “Des Fonctions due cerveau,” Revue des deux mondes, 2e période, tome 98, 1872 (373–385), 385.

[22] Bernard, Leçons, 1:67.

[23] Friedrich Nietzsche, The Gay Science, Walter Kaufmann, trans. (New York: Vintage, 1974), Bk. 3, Section 109, p. 169.

[24] Benjamin David Mitchell, Dancing in Chains: A History of Friedrich Nietzsche’s Physiological Relativism. PhD Diss., York University, Toronto, Ontario, 2016. https://yorkspace.library.yorku.ca/xmlui/bitstream/handle/10315/33337/Mitchell_Benjamin_D_2016_PhD.pdf?sequence=2&isAllowed=y. Accessed July 11, 2020.

[25] Nietzsche, Gay Science, Bk. 5 section 354, 297–299.

[26] The research university as we know it today is an originally German, and predominantly Prussian, Protestant institution. Over the course of just a few decades, following the founding of the University of Berlin in 1810 by Wilhelm von Humboldt, German universities developed from medieval theological seminaries to juggernauts of scientific and industrial research and became key organs of the state. By the establishment of the imperial German state in 1871, the research university had taken on pivotal importance in German society and politics. Beginning in 1876 with the founding of Johns Hopkins on the template of the University of Berlin, the United States began to import the model, which subsequently became the primary locus of scientific research worldwide. The new German research universities, however, retained their theology faculties, indeed until the present. The theology faculties modernized alongside the burgeoning scientific disciplines, developing a “scientific theology” that, in the Protestant universities, explicitly associated an empirical, mechanist, positivist approach to natural science with Protestantism and against Catholicism. See Riskin, Restless Clock, 253.

[27] Turner, 122.

[28] August Weismann, “On the Mechanical Conception of Nature,” in Studies in the Theory of Descent, edited and translated by Raphael Meldola (London: Sampson, Low, Marston, Searle, and Rivington, 1882), 2:634–718, on pp. 710, 711, 712; see also 716 on teleology and materialism.

[29] Turner, 289, 254, 248–251, 255

[30] William Wordsworth, “Lines Composed a Few Miles above Tintern Abbey, on Revisiting the Banks of the Wye during a Tour” (1798), in The Complete Poetical Works of William Wordsworth, edited by John Morley (London: Macmillan, 1888), lines 101, 102.

[31] Johann Gottfried Herder, Outlines of a Philosophy of the History of Man, 1784, translated by T. Churchill (New York: Bergman, 1966), 113, 99.

[32] Erasmus Darwin, “Extracts from Zoonomia, or the Laws of Organic Life,” in Romanticism and Science, 1773–1833, edited by Tim Fulford, 5:24–44 (London: Routledge, 2002), 44.

[33] Turner, 293.

[34] Turner, 296.

[35] Thomas Nagel, Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False (Oxford: Oxford University Press, 2012), 12, 93, 95.

[36] Darwin — Roland Trimen, January 16, 1868, Darwin Correspondence Project (hereafter DCP), “Letter no. 5790,” accessed on July 13, 2020, https://www.darwinproject.ac.uk/letter/DCP-LETT-5790.xml.

[37] Prum, 10, 55.

[38] Prum, 93-94,102–106, 212–214.

[39] Prum, 185-87, 189–190, 197–198.

[40] Prum, 14. See also 44, 68, 69, 79, 86, 133, 325.

[41] Prum, 33.

[42] Darwin to Wallace, April 14, 1869, in DCP, letter 6706.

[43] Darwin to Gray, May 22, 1860, in DCP, letter 2814.

[44] Wallace, “On the Origin of Human Races and the Antiquity of Man Deduced from the Theory of ‘Natural Selection,’” in Anthropological Review 2 (1864): clviii–clxxxv, in which Wallace had argued that human intellectual, moral, and social faculties would have been beneficial to the survival of the community of early humans and were therefore explicable by natural selection.

[45] [Wallace, Alfred Russel.] 1869b. Geological climates and the origin of species. [Review of Charles Lyell’s Principles of geology, 10th edition, and Elements of geology, 6th edition.] Quarterly Review 126: 359–94, on 391-94; Wallace, “The Limits to Natural Selection as Applied to Man,” in Contributions to the Theory of Natural Selection, 332–371 (London: Macmillan, 1870), 366–368.

[46] Darwin – Charles Lyell, 17 June 1860, in DCP, “Letter no. 2833,” accessed on July 17, 2020, https://www.darwinproject.ac.uk/letter/DCP-LETT-2833.xml

[47] Darwin to Wallace, April 14, 1869, in DCP, letter 6706.

[48]Alfred Russel Wallace, “The measurement of geological time,” in Nature 1 (1869–’70): 399–401, 452–455; DCP, “Letter no. 7086,” accessed on 17 July 2020, https://www.darwinproject.ac.uk/letter/DCP-LETT-7086.xml.

[49] Wallace, My Life: A Record of Events and Opinions, Volume 2 (London: Chapman and Hall, 1905), Volume 2: 22, 215,

[50] Wallace, Darwinism: An Exposition of the Theory of Natural Selection With Some of Its Applications (London: MacMillan, 1889), 283.

[51] Darwin to Wallace, 23 September [1868], in DCP, Letter no. 6386, accessed on July 17, 2020, https://www.darwinproject.ac.uk/letter/DCP-LETT-6386.xml

[52] Darwin to Wallace, June 17, 1876, in DCP, Letter no. 10538, accessed on July 17, 2020, https://www.darwinproject.ac.uk/letter/DCP-LETT-10538.xml. Fn. 3: “Wallace pointed out that the male argus pheasant’s head, which was unadorned, was completely concealed from the view of a spectator at the front by his ornamented wings; he added that this was a remarkable confirmation of CD’s view that coloured plumes were developed in the male bird for the purpose of display during the breeding season.”

[53] Wallace, Darwinism (1889), viii.

[54] St. George Mivart, The Genesis of Species (London: MacMillan, 1871), 288. Natural selection, Mivart maintained, was “inadequate as an agency without the existence of a profound, teleological cause underlying it.” Mivart, Nature and Thought: An Introduction to a Natural Philosophy (London: Kegan Paul, 1882), 208. The book is in the form of a dialogue between two friends, and these words are spoken by “Maxwell,” a clear stand-in for Mivart himself.

[55] Mivart, “[Review of] The Descent of Man, and selection in relation to sex,” in Quarterly Review 131 (July 1871): 47–90, on pp. 56, 62.

[56] Dawkins has embraced the label of neo-Wallacean — Dawkins, Ancestor’s Tale, 373 — and neo-Weismannist — Extended Phenotype, 113, 169.

[57] Weismann, The Germ Plasm: A Theory of Heredity (New York: Scribner, 1893), 217.

[58] “meaningless”: Wallace, Darwinism, 142; Weismann, “Mechanical Conception,” 672; Weismann, Essays Upon Heredity and Kindred Biological Problems (Oxford: Clarendon, 1889), 224; “arbitrary”: Weismann, Essays, 259–260.

[59] For example, Dawkins represents natural selection as simply selecting “good genes.” See Dawkins, The Selfish Gene (Oxford: Oxford University Press, 2006), 38, 41, 84, 157, 159, 160, 272; Ancestor’s Tale, 543. See also his use of the phrase “successful genes” in Extended Phenotype, 166, 170. There’s a certain circularity in Dawkins’s account since by “good genes” he seems to mean genes that succeed in replicating themselves a lot, i.e., in getting selected.

[60] Recently, Dawkins has considered the possibility that sexual selection “produces quirky, whimsical evolution,” but he remains agnostic about whether the results are fully “arbitrary” or only “apparently arbitrary” with regard to natural selection. Dawkins, Ancestor’s Tale, 370–375.

[61] Prum, 49.

[62] Prum, 148; see also 65, 66, 181.

[63] David Hume, A Treatise of Human Nature, T 2.1.1.3, SBN 276, https://davidhume.org/texts/t/full, accessed July 24, 2020.

[64] Immanuel Kant, Critique of Judgment, J. H. Bernard, ed. and trans. (London: MacMillan, 1914), Introduction, Part VII; §75.

[65] Prum, 84–87.

[66] Prum, 127–132.

[67] Prum, 134–135.

[68] Prum, 233.

[69] Turner, 8.

[70] Dawkins, Selfish Gene, 202.

[71] Prum, 250.

[72] Prum, 251, 255.

[73] Prum, 157, 161–165, 168, 173–174.

[74] Prum, 177–178.

[75] Prum, 199–201.

[76] Prum, 206–210, 214, 223.

[77] Prum, 174, 204.

[78] Prum, 177–178.

[79] Prum, 330.

[80] Prum, 149, 156.

[81] Robert McCloskey, Make Way for Ducklings (New York: Viking Press, 1941).

[82] Prum, 236, 242–243.

[83] Prum, 239.

[84] Prum, 298.

[85] Prum, 310.

[86] Prum, 264–265, 273–274, 276–277, 279.

[87] Herbert Spencer, Essays: Scientific, Political, and Speculative, Vol. 1 (London: Williams & Norgate, 1891), 109.