Years later, when the reclusive poet Emily Dickinson archly wrote that “we thought Darwin had thrown ‘the Redeemer’ away,” she was almost certainly remembering Asa Gray’s series of articles about the Origin of Species that appeared in the Atlantic Monthly during the summer of 1860. Dickinson’s father never purchased Darwin’s book, but he did subscribe to the Atlantic, and his daughter assiduously scoured the magazine each month. (It was the prominent Atlantic contributor and abolitionist Thomas Wentworth Higginson to whom she wrote in 1862, asking whether her verses “breathed” and initiating a lifelong correspondence.) As with many Americans, Dickinson’s first encounter with Darwin was through Gray’s reviews.
By February 1860 the book had already received notices in the New York Times, the Boston Daily Advertiser, and the Springfield Republican, as well as in Harper’s New Monthly Magazine, the North American Review, the New England Review, the Christian Intelligencer, the Methodist Quarterly Review, the American Theological Review, and the Biblical Repertory and Princeton Review. Some of these publications focused on the work’s ethnological implications. Others criticized the way Darwin’s ideas undermined religion. One pious reviewer noted that natural selection stripped divine intention from the center of the physical universe and replaced it with chance and accident. The Origin was nothing less than a “sneer at the idea of any manifestation of design in the material universe,” and its theories “repudiate the whole doctrine of final causes,” rendering obsolete “all indication of design or purpose in the organic world.” Another indignant critic, this one for the Christian Examiner, claimed that Darwin’s central idea was “neither more nor less than a formal denial of any agency beyond that of a blind chance.”
Gray would attempt to counter these attacks in his three-part series for the Atlantic, but before he could do so, he had to complete a lengthy review for the American Journal of Science, which would be published in March 1860. There he portrayed Darwin’s theory as a young combatant in an age-old war of ideas. Natural selection could be considered “atheistical,” he admitted, because it did not require God for its operation. But this was true of all theories that tried to explain physical phenomena. Darwin’s ideas were no different from those of Isaac Newton, whose “theory of gravitation and . . . nebular hypothesis assume a universal and ultimate physical cause, from which the effects in nature must necessarily have resulted.” No one seriously believed that gravity banished God from the universe. Gray wondered how any “scientific man” could believe that a material connection between diverse plant and animal species “is inconsistent with the idea of their being intellectually connected with one another through the Deity”?
The “scientific man” he referred to was Agassiz. Throughout his March article Gray argued for cautious, inductive reasoning—something that was impossible when one routinely made a priori assumptions about the role of a divine Creator in the workings of nature. For Gray, there were two ways of understanding the natural world: the transcendental and the material. Both approaches offered appealing explanations for how the universe had come into being, but while the idealistic view assumed an “independent, specific creation of each kind of plant and animal in a primitive stock,” Darwin’s more naturalistic description of creation began instead with “a single pair, or a single individual” that gradually transmuted into separate species. Gray admitted that the developmental theory, as it was commonly referred to, broke down a centuries-old belief that species were stable and immutable. But this belief made no sense when one examined the evidence. All species varied to some degree, some quite remarkably so. Offspring were never simply copies of one another. The source of these variations remained unknown, but their occurrence implied the possibility of change and differentiation.
The main problem with the idealist view of species was not its misreading of evidence, Gray asserted. It was that it relied entirely on a supernatural explanation. Agassiz’s science was “theistic to excess.” This was not to say God was absent from the creation of life—quite the opposite, Gray believed. But science was a method concerned with observing organisms, processes, and laws in the material world. There was simply no place in scientific inquiry for leaps of faith or speculation about the unseen. By referring “the phenomena of both origin and distribution [of species] directly to the Divine will,” Gray wrote, the idealist theory removed the study of organic life from “the domain of inductive science.”
In sharp distinction, Darwin’s new theory was grounded upon close and careful observation. It was based upon data that could be shared and verified. And it revealed something everyone intuitively knew because everyone had observed or experienced it: that “plants and animals are subject from their birth to physical influences, to which they have to accommodate themselves as they can.”
Gray admired Darwin’s book because it reinforced his conviction that inductive reasoning was the proper approach to science. Darwin’s book was both a primer and a meta-text about scientific theories: about their struggle to survive. Hypotheses and conclusions thrived only when they adapted to the harsh demands of evidence and repeatable testing. “A spirited conflict among opinions of every grade must ensue,” Gray observed about the theories of natural selection and special creation, “which—to borrow an illustration from the doctrine of the book before us—may be likened to the conflict in Nature among races in the struggle for life.”
This now seems like a rather obvious point to make. At the time it was radical. Gray was suggesting that whether or not Darwin’s ideas were correct was ultimately less important than how those ideas were to be evaluated. To reach a conclusion about evolutionary theory by way of emotion or inherited belief or any criteria other than empirical reasoning was intellectually untenable. It was dishonest and unsound. It was unscientific. What mattered for Gray was the careful judging and clear-eyed balancing of data. In order to grapple with Darwin’s ideas, one had to follow the evidence wherever it led, ignoring prior convictions and certainties or the narrative one wanted that evidence to confirm. Although he did not say it in quite these terms, Gray was suggesting that readers of Darwin’s book had to be open to the possibility that everything they had taken for granted was in fact incorrect.
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From his perch as the most eminent scientist in America, Louis Agassiz learned of Gray’s review with dismay. Agassiz had received an author’s copy of the Origin in December, around the same time as Gray. Darwin had written to him, “As the conclusions at which I have arrived on several points differ so widely from yours, I have thought (should you at any time read my volume) that you might think that I had sent it to you out of a spirit of defiance or bravado; but I assure you that I act under a wholly different frame of mind. I hope that you will at least give me credit, however erroneous you may think my conclusion, for having earnestly endeavored to arrive at the truth.”
Agassiz never replied.
He did, however, read the book—or at least a portion of it. Like Gray, he read with a pencil in hand, making notes as he went along. But those notes were of a decidedly different cast. “A sentence likely to mislead!” he scribbled. “This is truly monstrous.” About a quarter of the way through the Origin, he indignantly summed up what he took to be the author’s flawed methodology. “The mistake of Darwin has been to study the origin of species among domesticated animals instead of wild ones; his results concerning species are founded not on an investigation of species themselves but on an investigation of breeds.” He wasn’t finished. A few pages later Darwin indirectly attacked Agassiz by discussing the remarkable similarity of species in the same group or family. “On the view that each species has been independently created,” Darwin wrote, “I can see no explanation of this great fact in the classification of all organic beings.” Agassiz replied with exasperation in the margin: “Why not? does the excellences of the classification make it less likely to be the results of intelligent Creation? more likely to be the result of physical creation?” And when Darwin asserted that “every organic being is constantly endeavoring to increase its numbers,” Agassiz sputtered, “Why sir, there is room enough for all the ducks of the world in the forests of North America.” He forced himself to read a few more pages and then, in exasperation, skipped the second half of the book and hastily read its conclusion.
In January 1860 Agassiz discussed the book in public for the first time. “What has the whale in the arctic regions to do with the lion or the tiger in the tropical Indies?” he asked a large audience at the Boston Mercantile Library Association. “There is no possible connection between them.” Agassiz was nettled by Darwin’s hypothesis that all creatures were biologically linked. To him it was inconceivable that whales and lions could be linked by anything other than their mutual conception in the mind of the Creator. “There is behind them & anterior to their existence, a thought,” Agassiz thundered. “There is a design according to which they were built, which must have been conceived before they were called into existence.” He then fell back to his customary theme: “Whenever we study the general relations of animals, we study more than the affinities of beasts. We study the manner in which it has pleased the Creator to express his thoughts in living realities; and that is the value of that study for intellectual Man.”
The problem with evoking the Creator to explain the natural world, of course, was that it foreclosed other hypotheses. It favored dogma at the expense of logic and empiricism. “Tell Darwin that Agassiz has again failed to provide his promised criticism on Darwin for [the] Jour[nal],” Gray wrote Hooker shortly after the speech at the Mercantile Library Association. “I do not wonder that he hesitates to commit himself to print. I really think his mind has deteriorated within a few years.”
Unlike Agassiz, Gray returned to Darwin’s book again and again, rereading passages, marking fresh selections, savoring favorite paragraphs. The Origin was stuffed with one delicious detail after another. The tendency to catch rats instead of mice was a heritable characteristic of cats. A ripe asparagus plant would float in salt water for twenty-three days. All this minutiae added up to something; it formed a larger pattern, a coherent argument. One of the book’s signal accomplishments was to show how even the most trivial interaction between organism and environment was rich with meaning. Such tiny relationships, such insignificant causes and effects, could be decoded; they were in fact the very warp and woof of nature, diverse threads woven together to create a beautifully complex tapestry of life.
This perspective recommended itself to Gray because it revealed how experience and observation together produced facts. Like words in a sentence or pigments in a painting, facts were the essential building blocks of science, leading to the construction of plausible hypotheses, to sound conclusions. The cabinets of Gray’s herbarium—stuffed with tens of thousands of dried plants, each neatly labeled, each examined beneath his microscope and studied for affinities and slight variations—were the repositories of facts. Gray believed that a person could not begin to say anything sensible about how plants grew or thrived, how they were distributed across the Earth or how they interacted with one another in a given environment, until that person had mastered as many of these facts as humanly possible.
Gray’s American Journal of Science article occasionally disagreed with Darwin. It raised questions about reversion, or the tendency of offspring to exhibit characteristics of older ancestors. And Gray worried, like George Templeton Strong and others, about the absence of fossil records. He quibbled over Darwin’s phraseology. But just below the surface of these concerns, he repeatedly challenged Agassiz’s notions about science, argumentation, and the production of hypotheses. And he took Agassiz to task on the matter of race.
It had long been an open secret at Harvard that Agassiz felt a visceral repulsion toward black people. His Swiss upbringing might have conditioned this attitude, which would have been reinforced when he studied with Cuvier, who once described Africans as “the most degraded of human races, whose form approaches that of the beast and whose intelligence is nowhere great enough to arrive at regular government.” But there was something particularly violent about Agassiz’s reaction to the black servants he encountered for the first time during his tour of America. Traveling with Gray along the eastern seaboard in December 1846, he wrote a long letter to his mother describing the American scene. “It was in Philadelphia that I first found myself in contact with Negroes,” Agassiz described, proceeding to detail his disgust at the physical characteristics of black hotel servants and waiters. The “feeling that they inspired in me,” Agassiz confessed, “is contrary to all our ideas about the confraternity of human types (genre) and the unique origin of our species. . . . What unhappiness for the white race—to have tied their existence so closely with that of Negroes in certain countries! God preserve us from such a contact.”
Agassiz did not condone slavery. He thought the institution in appalling taste, cruel to its victims, demeaning to its practitioners. Over time he even came to consider himself a reluctant abolitionist, advocating, when pressed, for the legal equality of blacks. But he never swerved from his basic conviction, forged in the moment when a black man waited on him, that people of African descent had been created separately from Europeans. A decade before reading Darwin’s book, in 1850, Agassiz traveled to South Carolina to address a group of Southern scientists who were particularly interested in his ideas about the separate creation of races. While there he asked his host, the physician Robert W. Gibbes, if he might examine slaves from various African tribes; he wished to catalog the anatomical differences that separated them from whites. Half a dozen slaves were procured from nearby plantations and brought to Agassiz. They stood before him, neither smiling nor looking directly at him, and tried to answer his questions. At some point he asked each one, male and female, to strip to the waist, so that he might study them better. “Agassiz was delighted with his examination of Ebo, Foulah, Gullah, Guinea, Coromantee, Mandingo, and Congo negroes,” Gibbes later recalled. The great naturalist had apparently seen enough to confirm him in his belief that “they have differences from other races.”
Gibbes may have overstated the case somewhat. Agassiz never went as far as some polygenists; he never claimed that blacks and whites belonged to separate species. But he did believe they had been created mutually exclusive from each other, fashioned by God to thrive in their separate provinces. For this reason he was especially horrified by the prospect of the two races intermingling. His principal opposition to slavery was not that it converted people into chattel property or oppressed unfortunate humans by coercing them to perform backbreaking labor. Rather, he was horrified that the institution fostered interbreeding—what was then known as “amalgamation.” The prolific intermixing of blacks and whites through cohabitation and sexual congress was for Agassiz an abomination. It blurred and confounded racial categories. It violated the calm and logical order of the universe and disregarded nature’s most fundamental divisions, which is to say, it violated God’s will.
“Conceive for a moment the difference it would make in future ages,” Agassiz wrote, “for the prospect of republican institutions and our civilization generally, if instead of the manly population descended from cognate nations [he meant Europe] the United States should hereafter be inhabited by the effeminate progeny of mixed races, half Indian, half negro, sprinkled with white blood.” This alarming future was not only possible but in fact probable, given the close proximity of two races that were “more widely different from one another than all the other races.” It was simply inconceivable that blacks and whites could live together as equals. Amalgamation, he added, was “one of the most difficult problems upon the solution of which the welfare of our own race may in measure depend.”
Now, in his article for the American Journal of Science, Asa Gray waded into the polygenesis controversy. He began with an obvious scientific point: according to Linnaeus, two species could not interbreed or produce fertile offspring. That blacks and whites quite clearly did produce offspring together had been dismissed by polygenists, who claimed that biracial children were infertile. “The best marked human races might offer the most likely case” for testing these assumptions, Gray mused. “If mulattoes are sterile or tend to sterility, as some naturalists confidently assert,” that would afford evidence of two distinct human species. “If, as others think, no such tendency is made out, the required evidence is wanting.” He hypothesized that human races might one day become separate species, given enough time and separation from one another. The crucial point, however, was that they shared the same inheritance—a claim his esteemed colleague, Louis Agassiz, disputed without providing evidence.