In the summer of 1860, Charles Darwin wrote his friend and champion Thomas Henry Huxley to discuss the American campaign currently being waged on behalf of his theory. Restless after completing his book, he had hurled himself into a fresh batch of experiments carried out in his secluded home in the Kentish countryside. He planted orchids and dissected insects. He plundered his wife’s embroidery basket for brightly colored wools and silk to tie onto the stakes that supported his various plants. He covered her azaleas with netting and draped the beans with gauze. (He didn’t bother to tell anyone why he was doing these things.) In the lazy, still afternoons he pollinated primroses with a small paintbrush or attended to the trays of seedlings that were scattered in his study and the outbuildings throughout his estate. In the afternoons he wandered along the path he called the Sand Walk, a trail that skirted a sun-dappled grove near the garden at Down House. He strolled with hands clasped loosely behind his back, head down, pondering.
Throughout July and August he was drawn to sundews: tiny plants that consumed flies and other insects by wrapping sticky leaves around their victims. How did these slow-moving plants trap flies? he wondered. Why did they eat meat instead of using the sun and soil as nutrients, like other plants? Were they in fact some transitional organism between flora and fauna, some strange hybrid creature that embodied features from both? He fed his growing collection of carnivorous plants with scraps of leaves, paper, bits of feather and wood, moss, milk, egg whites, sugar, raw meat. In one harebrained experiment, he paralyzed the plants with doses of chloroform.
Like a fly in the sticky clutches of a sundew, he felt as though he were being slowly digested—or at least that his book was. By July 1860 the Origin of Species had been reviewed by nearly every major British quarterly, defended and denounced by England’s top men of science, lampooned by cartoonists, and excoriated in the religious press. Richard Owen, the nation’s premier primate anatomist, had anonymously attacked the work in the Edinburgh Review, lambasting everything from Darwin’s ideas and prose style to the friends he kept. Domestic animals, the Christian Observer tartly noted, varied only because God wished them to vary. And the popular press enjoyed titillating comments about ape ancestry, the British Quarterly printing an imaginary scene in which a monkey proposed marriage to an honest, goodhearted heroine of the sort one might find in a novel by Thackeray or Eliot.
But Darwin also had his supporters. Joseph Dalton Hooker, Charles Lyell, and Thomas Huxley united to defend the theory of natural selection in Great Britain. Huxley was especially pugnacious and would soon become known as “Darwin’s bulldog.” He believed that the debate over evolution entailed much more than a particular theory. It was an epic battle in the war between science and religion. Huxley stood on the side of clear thought and rational empiricism; with sardonic glee, he blasted theological claptrap and old-fashioned beliefs. “Who shall number the patient and earnest seekers after truth from the days of Galileo until now,” he wrote in the Westminster Review, “whose lives have been embittered and their good name blasted by the mistaken zeal of Bibliolaters?” Religion had blighted the lives of earnest truth-seekers, but disinterested science would surely triumph in the end. “Extinguished theologians lie about the cradle of every science as the strangled snakes beside that of Hercules, and history records that whenever science and dogmatism have been fairly opposed, the latter has been forced to retire from the lists, bleeding and crushed, if not annihilated; scorched if not slain.”
The debate in England came to a head that July in Oxford, at the annual meeting of the British Association for the Advancement of Science. There the Victorian bishop Samuel Wilberforce agreed to speak against the new theory, ponderously expressing his “disquietude” at the possibility of descending from apes. Huxley whispered to a friend, “The Lord hath delivered him into mine hands,” and rose onto the platform to reply, “If I would rather have a miserable ape for a grandfather or a man highly endowed by nature and possessed of great means and influence, and yet who employs those faculties for the mere purpose of introducing ridicule into a grave scientific discussion—I unhesitatingly affirm my preference for the ape.”
A similar battle was raging in America. Throughout the blistering summer months in Cambridge, as Gray’s essays for the Atlantic began to appear, Louis Agassiz continued to sputter and rail at the new theory. His response to Gray’s important essay for the American Journal of Science had still not been published—it had not in fact been written. He promised once and for all to demolish Darwin’s theory of natural selection as soon as he could pull himself away from the completion of his grand museum. Darwin wrote about these developments to Huxley that summer. He reported on the American debate over his theory and wryly observed that Agassiz had his hands full with Asa Gray, whose first article for the Atlantic would soon be reaching England. “Gray goes on fighting like a Trojan,” Darwin wrote. He could scarcely contain his glee.
• • •
The Atlantic seldom published the names of its authors in those days, but everyone seems to have known that Gray was the author of the July article defending Darwin. Entitled “Darwin on the Origin of Species,” it was an instant success. “‘Almost thou persuadest me to be a Darwinite—,’” wrote W. H. Harvey, a Dublin algologist and evolutionary skeptic who read the essay as soon as it arrived in Ireland: “not quite, but thou persuadest me to be a Grayite.” Darwin himself wrote in late July to say that the article was “uncommonly pleasantly written, & will tell well on the public. . . . My conclusion is that you have made a mistake in being a Botanist, you ought to have been a Lawyer, & you would have rolled in wealth by perverting the truth, instead of studying the living truths of this world.”
That same month Gray received a letter from Charles Eliot Norton, the translator of Dante with whom he had discussed the Origin of Species in Jeffries Wyman’s office on the day after Christmas. Norton thanked Gray for his review, praising its comprehensiveness and fair-mindedness. He had read the article twice and was much taken by Gray’s understated differences with Darwin. For Norton it was especially noteworthy that Gray held out the possibility “that specific creation may have had a part in the existing condition of races, as well as variation and natural selection.” Norton had immediately understood that Darwin’s theory implied a biological connection between humans and apes. He had taken comfort in Gray’s statement in the July essay that more evidence was required to settle this issue. In a rare instance of question begging, Gray announced to his readers: “we must needs believe in the separate and special creation of man, however it may have been with the lower animals and plants.” Norton welcomed this passage because it reinforced his own opinion that humans were categorically different from beasts: sentient creatures capable of producing Renaissance masterpieces and intricate allegorical poetry. “I wish that you would give [this idea] a fuller treatment in a succeeding number,” he wrote.
Like many other readers, Norton was convinced that natural selection failed to explain the special condition of humankind. The theory also failed to explain the transformation of inanimate matter into living beings—the true origin of life. “It is plain that neither separate acts of origination, nor the action of all the principles of derivation taken together will alone explain the facts of organic existence,” he continued in his letter to Gray. “. . . It does not seem probable that Darwin’s theory, which at first sight appears to do away with specific creation, may lead to an understanding of the laws of origination as well as of those of development.” Natural selection might explain the emergence of one species from another, he conceded, but it remained silent on that mysterious moment when matter first flickered into life.
Gray had not addressed the issue of life’s origins in his first essay for the Atlantic. Norton encouraged him to do so. “Why should not we have the theory of Gray as well as of Darwin,” he wrote, “—a theory embracing both specific acts of creation and general principles of derivation, and showing the harmony between them?” Gray agreed to tackle the problem in his second article, which was published in August and titled, like the first, “Darwin on the Origin of Species.” There he promised to “inquire after the motives” that impelled Darwin to “press his theory to . . . extreme conclusions” and to propose that all living things could be traced to a single primordial organism.
“Why,” he asked, “should a theory which may plausibly enough account for the diversification of the species of each special type or genus be expanded into a general system for the origination . . . of all species?” Part of the answer was simple: Darwin’s theory accorded with “great classes of facts otherwise insulated and enigmatic.” It explained phenomena that had been previously inexplicable. Why did bird and mammal embryos have gills? Why did two remarkably distinct creatures such as the giraffe and the elephant have the same number of vertebrae in their neck? Community of descent, Gray wrote, explained with sublime eloquence these strange and wonderful occurrences.
Even plants and animals were more similar than commonly assumed. Algae, for instance, were at first “characteristically animal, and then . . . unequivocally vegetable,” Gray explained. (He was referring to the ability of algae to consume other plants like herbivores.) Members of the two kingdoms shared other structural similarities, such as the organs of reproduction; conversely, “lower grades of animals” such as amoebas sometimes produced “offshoots” that eventually separated from the parent stock. These characteristics might be taken for homologies, or similarities that were due to relatedness.
Nothing in nature was as clear-cut or as orderly as it seemed. Some plants were bisexual, Gray wrote, others unisexual. The human fetus had characteristics of a fish. The natural world was fluid and uncertain, its categories radically unstable. Gray was not arguing that differences among species, genera, and families were illusory or fictitious. He was pointing out, rather, that any critique of Darwin’s theory had to take into account all of the anomalous facts that the theory explained.
But for the first time in his discussion, Gray hesitated. He wavered in his support for Darwin’s theory. Natural selection could explain much, he granted, but could it explain all of nature’s marvels? Was one to believe that chance governed every aspect of the universe? Wasn’t it just as likely that some thread of design stitched together pieces of the universe? How else, he asked, explain the eye?
Since at least the time of Socrates, natural philosophers had considered the eye proof that creation had been fashioned by a supernatural being. In 1802 the natural theologian William Paley extended the premise: not only was the eye a remarkably designed optical structure, Paley wrote, but “there is to be seen, in every thing belonging to it and about it, an extraordinary degree of care, an anxiety for its preservation, due, if we may so speak, to its value and its tenderness.” For Paley, the eyeball’s position beneath thick supraorbital bones, as well as the protection afforded by the eyelid, suggested to him that the Creator considered the eye especially worth protecting.
Darwin had anticipated this argument in the Origin. It seemed absurd to “suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection.” Yet, he continued,
reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ ever be useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real.
The sentence is as carefully constructed as a legal brief. Darwin undermines the canonical argument for design in nature, asserting that random variation explained the formation of the eye just as persuasively as divine fiat. All one had to do was imagine gradual adaptive change occurring over vast stretches of time, from primitive eye-buds to the acute optical organ of a hawk.
Gray struggled with this conclusion. In his copy of the Origin, he responded to Darwin’s initial statement that such a hypothesis seemed “absurd in the highest degree” by penciling in the margins, “So it does.” Earlier that year he had written Darwin to say that “what seems to me the weakest point in the book is the attempt to account for the formation of organs,—the making of eyes, &c by natural selection. Some of this reads quite Lamarckian.” He meant that Darwin sometimes implied that animals willed the improvement of their vision, much as giraffes, in Lamarck’s example, had willed longer necks by stretching them. Descent through modification relied on accidental variations.
Darwin replied, “About weak points I agree. The eye to this day gives me a cold shudder, but when I think of the fine known gradations, my reason tells me I ought to conquer the cold shudder.” Creatures still existed with rudimentary eye buds, he continued. One could trace the powerful eyesight of predators to these primitive photosensitive nerves. “I feel pretty sure from my own experience,” Darwin continued, “that if you . . . keep the subject of Origin of Species before your mind, that you will go further & further in your belief.—It took me long years & I assure you I am astonished at the impression my Book has made on many minds.”
But Gray remained skeptical. In his second Atlantic essay, he asked how it was possible that blundering, haphazard chance could account for “the most perfect of optical instruments”? How could accidental variation produce this marvel of exquisite form and function? Surely some deeper purpose or design guided its development. “A friend of ours,” he noted, privately nodding to Darwin, “who accepts the new doctrine, confesses that for a long while a cold chill came over him whenever he thought of the eye.” But Gray was really speaking about himself, not his friend in England.
Something had happened to Gray while he worked on his essays for the Atlantic. A wave of unbelief—a surge of dizzying, sickening doubt—swamped him. Darwin’s description of a world characterized by endless struggle and prolific death had collided with his religious faith. It called into question God’s benevolent hand. Suddenly he felt insignificant: unsheltered and oppressed. Darwin’s book rendered nature little more than an empty machine. Sometime that summer Gray’s world suddenly became quaint and pitiable.
We know this happened because of the abrupt and strong response it provoked in Darwin. Replying to a letter from Gray that is now lost, Darwin wrote, “In truth I am myself quite conscious that my mind is in a simple muddle about ‘designed laws’ & ‘undesigned consequences.’” Gray had apparently asked whether natural selection might be the mechanism of intelligent design. Might not God use evolution to produce His creation? Darwin confessed his own confusion about the matter. While he resisted embracing a purely material philosophy, he wrote to Gray, he could find little consolation in the traditional Christian explanation of events. The natural world was simply too murderous and too cruel to have been created by a just and merciful God. “I see a bird which I want for food, take my gun & kill it, I do this designedly.—An innocent & good man stands under a tree & is killed by flash of lightning. Do you believe (& I really shd like to hear) that God designedly killed this man? Many or most persons do believe this; I can’t & don’t.—”
It was, to put it mildly, a sensitive topic. Gray was a devout Presbyterian, a believer in the Nicene Creed. Throughout his long and illustrious scientific career, he had managed to square his faith in God with his study of the natural world. Sometimes this required him to compartmentalize; after all, by its very definition, science could never settle questions of the spirit, committed as it was to the study of matter. But until now these two very different modes of understanding the world had always seemed to complement each other. God had created a wondrous planet; the job of science was to study His work and, in so doing, to celebrate it.
Darwin injected doubt into this process. If natural selection produced new species by purely mechanistic means, how did we know the rest of the universe hadn’t been created by physical processes? About that man struck by lightning—Darwin asked Gray, “Do you believe that when a swallow snaps up a gnat that God designed that particular swallow shd snap up that particular gnat at that particular instant?” Darwin was perhaps alluding to Christ’s words in the Gospel of Matthew: “Are not two swallows sold for a farthing? and one of them shall not fall on the ground without your Father.” But he had a different explanation than the Bible: “I believe that the man & the gnat are in the same predicament.—If the death of neither man or gnat are designed, I see no good reason to believe that their first birth or production shd be necessarily designed.”
Worried he might have offended his American friend, Darwin hastily concluded, “Yet, as I said before, I cannot persuade myself that electricity acts, that the tree grows, that man aspires to loftiest conceptions all from blind, brute force.”
• • •
Darwin told Thomas Huxley that Gray resembled a Trojan, fighting obsolete science in the name of evolutionary theory. Increasingly, however, Gray began to feel less like a Trojan and more like a Trojan Horse. With his calm and genial voice he had smuggled Darwin’s ideas behind the ramparts of American culture—into academies and churches and publishing houses—where they could colonize the minds of America’s intellectual class. He had done so willingly and without stint because Darwin’s theory was a classic example of evidence-based science. But he had also done so because he wanted to place American botany at the forefront of international science and because of his long-standing antagonism toward Louis Agassiz and the racist demagoguery of the polygenists. Taken together, these factors pushed him to accept Darwin’s premises more enthusiastically than he might otherwise have done. They encouraged him to become the foremost American advocate for the theory of natural selection.
What he didn’t realize—at least until it was too late—was that the Origin was a kind of Trojan Horse, too. It had entered American culture using the newly prestigious language of science, only to attack, once inside, the nation’s cherished beliefs. Once the Origin of Species gained admission inside a reader’s head, it began to compete with all sorts of dearly held convictions, struggling against biblical accounts of the Earth’s age and beginnings, destroying consolatory views that had served as a bulwark for much of history. With special and desolating force, it combated the idea that God had placed humans at the peak of creation.
Now, in the summer of 1860, a similar process was happening to Gray. Just as his essays were appearing in the Atlantic, he experienced second thoughts about evolutionary theory. As if sensing this change, Darwin wrote in September to say that he hoped Gray would continue to support his theory. “I am thinking of taking a very great liberty; but after much consideration I do not think you can object; you said that it was known that you were the author of the 1st article; & as the best chance of getting it reprinted in England in a scientific journal wd be to affix your name, I think of doing this & I hope to Heaven that you will not think this an unwarrantable liberty. I think most highly of this Article & I cannot bear to think it shd not be known in England.”
Gray gave his blessing to the venture, but his third essay, published in October, revealed his increasing difficulty aligning Darwin’s theory with his own religious convictions. Entitled “Darwin and His Reviewers,” Gray’s final article began with a concession: “The origin of species, like all origination . . . is beyond our immediate ken.” Given the limits of our knowledge, we can only hypothesize about first causes and ultimate beginnings. At present, two explanatory hypotheses were available: “One, that all kinds [of species] originated supernaturally . . . the other, that the present kinds appeared in some sort of genealogical connection with other and earlier kinds.” Gray cautioned against settling the point too quickly—“a wise man’s mind rests long in a state neither of belief nor of unbelief”—and he elaborated on this point: “Most people, and some philosophers, refuse to hold questions in abeyance, however incompetent they may be to decide them.” Something in human nature required answers for even the most difficult questions. “Sometimes, and evidently in the present case, this impatience grows out of a fear that a new hypothesis may endanger cherished and important beliefs. Impatience under such circumstances is not unnatural, though perhaps needless, and, if so, unwise.”
Gray now proposed that natural selection might be the process by which God had fashioned the world: “Agreeing that plants and animals were produced by Omnipotent fiat does not exclude the idea of natural order and what we call secondary causes,” he wrote. With this statement Gray became the first to make a theological case for Darwinian theory. Natural selection, he suggested, might be God’s chosen method of creation. This idea would grow increasingly popular in the future because it seemed to resolve the tension between scientific and religious accounts of origins. But it represents a stunning shift for Gray. Before now, he had always insisted that secondary causes were the only items science was qualified to address. First, or final, causes—the beginning of life, the creation of the universe—were the purview of religion: matters of faith and metaphysics.
“Darwin’s particular hypothesis, if we understand it, would leave the doctrines of final causes, utility, and special design, just where they were before,” Gray told his readers. In the ancient primordial past, inanimate matter had inexplicably become animate. Darwin assumed there was a material explanation for this event; Gray believed that since science could not account for it, there was a chance God had intervened.
He returned, one more time, to the eye. Darwin’s theory asserted that all adaptations were “fortuitous or blind.” Gray could not accept this. How could “blind forces” produce organs precisely adapted to specific ends? How could blundering accident produce eyes that were “better adjusted and more perfect instruments or machines than intellect (that is, human intellect) can contrive and human skill execute”?
In making this argument, Gray failed to acknowledge a crucial point of Darwin’s theory. The eye of whales and hawks and humans had not evolved to enjoy a cerulean summer sky or to glory in God’s creation. They had not been fashioned to enjoy the pigments of paint or the delicate tints of autumn leaves. They had developed over aeons in order to plunder, pillage, and overpower: to enable their particular species to survive in the competitive struggle of life. Gray could concede this argument to animals. But he had more difficulty when it came to people. After all, humans were endowed with a moral sense and a perception of divinity.
Gray told his Atlantic readers that Darwin’s theory, correctly understood, “concerns the order and not the cause, the how and not the why of phenomena.” It left questions of design untouched. To illustrate this point he employed an image that would soon be used by others in subsequent debates about natural selection. He asked his readers to imagine streams flowing down a slope. The streams were the counterpart of natural selection. They “may have worn their actual channels as they flowed, yet their particular courses may have been assigned; and where we see them forming definite and useful lines of irrigation, after a manner unaccountable on the laws of gravitation and dynamics, we should believe that the distribution was designed.”
The passage bears a striking resemblance to Thoreau’s description of the “sand foliage” in Walden. It shares Thoreau’s desire to find a deep underlying law in the seemingly random occurrences of water and soil. But in Gray’s analogy the unpredictable movement of streams down a hill is meant to represent variation among species. If streams and variations follow general laws, their mechanisms are unknown. More important, while both resist a strict determinism, both also prove beneficent—Gray’s streams produce “definite and useful lines of irrigation.” Variations enable species to survive, just as the trickle of streams irrigates the soil. In these obscure operations, Gray professed to see design.
The problem with the analogy was that it used a purely physical process to infer the actions of a Creator. Gray had leaped beyond his own rules of science, speculating about something that was untestable. Abandoning scientific rationalism, he found an intelligent cause “forming definite and useful lines of irrigation, after a manner unaccountable on the laws of gravitation and dynamics.”
At some level he must have known that this argument failed to adhere to his own definition of science. But the simple truth was that he found it impossible to live in the world Darwin had imagined: a world of chance, a world that did not require a God to operate. In this way, he was closer to Louis Agassiz than he cared to admit. Like Agassiz, Gray refused to believe that life was a product of pure chance but thought it instead rather like the eye: its splendor inexplicable without a First Cause. “Chance carries no probabilities with it,” he wrote in the third essay for the Atlantic, “can never be developed into a consistent system, but, when applied to the explanation of orderly or beneficial results, heaps up improbabilities at every step beyond all computation.” What Gray meant was that while natural selection might be the process that formed the eye, this process had to be guided by a wise and overseeing providence. The alternative was too meaningless to consider. “To us, a fortuitous Cosmos is simply inconceivable. The alternative is a designed Cosmos.”