The Reluctant Mr. Darwin (3 page)

He wrote the notebook entries in telegraphic style without much concern for punctuation or grammar. There were insertions, cross-outs, abbreviations, bad spellings. He had trouble with “heredetary,” and with “Scicily” (or was it “Siicily”?), an island less unique zoologically than the Galápagos, though harder to spell. He was brainstorming. The written words were just a record for his own memory. He started with big questions. “Why is life short.” And, following Grandpa Erasmus: Why is sex so important? From there he went straight to a crucial insight—that the mixing bowl of sexual reproduction somehow allows creatures to vary. Offspring differ from their parents. Siblings differ from one another, unless they happen to be identical twins. Body patterns change slightly from generation to generation; so do aspects of intellect and instinct. One result: “adaptation.” To what eventual effect? Put a single pair of cats or dogs onto an island, Darwin suggested, and let them breed there, slowly increasing in number despite the pressure of enemies; then “who will dare say what result.” He dared, but only to himself: “According to this view animals, on separate islands, ought to become different if kept long enough.” There was
something
about islands. Their simplicity and isolation and anomalous faunas, like premises of a thought experiment, helped clear the head.

For instance, take the Galápagos tortoises and mockingbirds, or the miniature foxes he'd seen in the Falklands. “Each species changes,” Darwin wrote. This alone was a bold statement, explicitly contradicting orthodox tenets, both in science and in religion. Furthermore, changing species diverge continually from one another, he hazarded, producing the gaps between genera and still broader categories of classification, such as family, order, class: the diversity of life. On one notebook page he drew a rough diagram of a lineage, like a tree trunk, splitting into limbs and branches. The end of each branch he labeled with a letter, representing a species. Birds and mammals, vertebrates and insects, even animals and plants—they were all branches from a single primordial trunk. His mind was flying. Then he wrote: “Heaven knows whether this agrees with Nature:
Cuidado
.” Not so fast, Charles. Be careful.

What's remarkable in the “B” notebook, besides the private evidence of his leap into evolutionary thinking, is the breadth of facts, notions, sources, and themes that Darwin was already pulling together, some of which would remain pillars of his work and his arguments for decades to come. He seized on the idea of adaptation. He saw that variation among offspring made it possible. He grasped the significance of biogeography (that is, geographical patterns of species distribution) and of classification (how living things can be sorted into groups) as evidence that transmutation and divergence of species have occurred. He called attention to rudimentary structures—limbs and organs that seem too small, too primitive to be useful, as though they haven't been fully formed, or have latterly fallen into disrepair. Such rudiments exist even among humans. Why do men have nipples? Darwin, restless seeker, wanted to know. Why do some species of beetle, especially on windy islands, possess good wings sealed uselessly beneath fused elytra (those shelly wing covers) that can never open? Why would a smart, busy God create something so dumb and wasteful?

Flightless beetles were puzzling enough, but he wondered also about flightless birds, with their nubby little wings—the ostrich, the penguins, the rheas he'd seen in Patagonia, the apteryx of New Zealand. “Apteryx,” he wrote, “a good instance probably of rudimentary bones.” He hadn't collected an apteryx during his New Zealand stop with the
Beagle
, hadn't even glimpsed one, and he didn't call it by its native Maori name, the kiwi. But he knew enough from his reading to mention it, a small piece of the great puzzle, whose place would be found later.

3

For two years he lived a strange double life, like a spy in the corridors of the British scientific establishment, which at that time was closely attuned to Anglican orthodoxy and grounded in the tradition of natural theology.

Biology hadn't yet emerged as a secular profession. Studying nature was considered a path toward piety. Many prominent natural historians such as Gilbert White, author of a mellifluous little book of observational lore titled
The Natural History of Selborne
, first published in 1789, were clergymen who preached on Sunday and watched birds or chased insects the rest of the week. A blacksmith's son named John Ray, after an education at Oxford (which was then an Anglican university, like Cambridge), had sounded the theme back in 1691 with his book
The Wisdom of God Manifested in the Works of the Creation
. William Paley reaffirmed it in 1802 with
Natural Theology
, subtitled
Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature
, a book Darwin had read for amusement during his time at Cambridge. Paley popularized the analogy of the divine watchmaker: If we find a watch lying on the ground, we infer that some intelligent craftsman has made it; if we find intricately designed and marvelously adapted animals and plants, we should likewise infer that some wise, powerful Creator has made them. A series of books called the
Bridgewater Treatises
, published during the 1830s, offered eight further statements, from highly respected researchers, of the same argument about God's wisdom, power, and direct role in creating the natural world piece by piece. One of those
Bridgewater
authors was William Whewell, a polymathic scholar and science philosopher whose influence spread in many directions, and who invented the very word “scientist.” Whewell's treatise considered astronomy and physics “with Reference to Natural Theology.”

Behind the Paleyite natural theology lay even deeper and older forms of conventional belief, such as essentialism, the notion that reality is undergirded by a finite number of “natural kinds,” the essential patterns or archetypes of entities seen in the world. This one goes back to Plato. Following his influence, essentialists held that these natural kinds are discrete and immutable, and that physical objects are merely their inexact manifestations. Geometric shapes, for instance, were thought of as natural kinds—triangles being always three-sided, various in their minor characteristics (equilateral, isosceles, scalene) and forever distinct from rectangles or octagons. Inorganic elements were another example—iron being always iron, and lead always lead unless some alchemist found a magical way of turning it into gold. Animal and plant species were also considered natural kinds, rigidly demarcated and unchangeable, though individual dogs or chickens might be various
within
their hard-sided categories. The essential form of a species, according to this view, is more fundamental and durable than the individuals embodying it at a given time. That's what William Whewell meant when, in 1837, he wrote emphatically: “
Species have a real existence in nature
, and a transition from one to another does not exist.” To believe otherwise was to reject an assumption that was interwoven with ecclesiastic teachings and ideas of civil order.

Whewell, whose interests and writings ran to geology, mineralogy, political economics, moral philosophy, and German literature as well as astronomy and biology, became one of the heavyweight intellectuals of his time. The comment about species is from his
History of the Inductive Sciences
, produced in a later intellectual generation and a more rigorous scientific spirit than Paley's
Natural Theology.
Other British scientists and philosophers contemporary with Whewell, such as John Herschel and John Stuart Mill, shared that lingering belief in natural kinds, buried beneath their disagreements about scientific method and logic. In France, the eminent comparative anatomist Georges Cuvier proposed a system of animal classification—sorting every species into one of four great
embranchements,
or groups—that also rested on essentialist assumptions. Finding order within the animal world meant, to Cuvier, reading the evidence in each species for its conformity with an underlying essence, not the clues suggesting change and divergence over time. A philosopher of science from our own era, David Hull, has traced this vein of essentialism in early nineteenth-century biological thinking. Hull concludes: “Seldom in the history of ideas has a scientific theory conflicted so openly with a metaphysical principle as did evolutionary theory with the doctrine of the immutability of species.”

Darwin had read Herschel, as well as Paley, back at Cambridge. Whewell had been a professor of mineralogy there. Essentialism and natural theology were as thick in the air of Darwin's world as coal smoke and the scent of horse manure. True, those weren't the only contemporary perspectives on the natural world. The private medical schools of London and Edinburgh harbored wilder ideas during the 1830s, including some inchoate versions of evolutionary progressivism. But those institutions, which employed some professional anatomists who taught by dissecting human bodies, who lived on their salaries and not on inherited wealth, and who tended toward radical politics, were alien to Darwin, despite the family tradition of doctoring. He had tried medical training himself, in Edinburgh at age sixteen, following the footsteps of his brother (in the shadow of his father), and he hated it. After two years, bored by the lectures and appalled by the bloody operations done without anesthetic, Charles had scooted down to Cambridge for a drier, less gruesome education. While there, at Christ's College, he had drifted toward clerical ordination, not from any sense of vocation (he wasn't devout) or Church commitment (he'd descended from Unitarians on his mother's side and Darwin freethinkers like his father and old Erasmus) but by the least-worst logic that it would allow him to find some respectable niche as a parson-naturalist, after the model of Gilbert White. The
Beagle
trip had intervened. The ship carried him a long way from Christ's College but it eventually returned him to the same social context he had left behind, in which many of his scientific teachers, friends, and connections—John Henslow and Adam Sedgwick at Cambridge, Leonard Jenyns, the entomologist Frederick Hope, William Whewell himself—were Anglican clergymen. Even his scientific idol, Charles Lyell, had imbued
Principles of Geology
with an orthodox view of biological creation. During 1837 and '38, Darwin began steeling himself to shock and scandalize them all. His view of mutable species directly contradicted their essentialism and all the pious science-flavored theologizing that stood upon it. He poured his dark speculations into the transmutation notebooks while conducting himself outwardly as a clubbable young naturalist on the rise.

He cut back on his socializing, with apologies about being too busy, then added to his chores and his status by accepting a role as secretary to the Geological Society, under Whewell's presidency. He finished the manuscript of his
Beagle
journal (but it couldn't be published until FitzRoy's book was ready), and talked his way into another big publishing venture: a lavish compendium to be called
The Zoology of the Voyage of H.M.S. Beagle
. He would be the editor of this multi-volume
Zoology
, gathering contributions from his consulting experts, writing introductions and commentaries, commissioning expensive illustrations, to be financed with a grant from Her Majesty's Treasury. He was now well embedded within the seamless matrix of government, Church, and gentlemanly science. Secretly, he continued talking to himself in the seditious notebooks.

When he'd filled notebook “B,” he started a new one, in maroon leather and labeled “C,” after which would come “D” and “E,” each devoted to transmutation. He was reading widely in the literature of exploration and natural history, plus a diverse selection of books on animal and plant breeding, history, and philosophy of science; and he had begun putting cryptic questions to anyone who knew anything about the odd, targeted topics that interested him. He debriefed his father, a gusty source of lore on human mental attributes, and his father's gardener. He quizzed livestock breeders about variation and heredity among domestic species. There were so many unknowns to consider. How did inheritance work? What was the difference between species and varieties? What might be deduced from patterns of species distribution around the world? All the islands of Oceania have skinks with golden streaks, he noted. Wild pigs in the Falklands grow stiff, brick-red hair. The kingfisher of the Moluccas scarcely differs from European kingfishers, he wrote, except that its beak is longer and sharper. Were they separate kingfisher species, or just varieties? Cassowaries in New Guinea, tenrecs in Madagascar, geckos on St. Helena. There are no snakes on islands of the central Pacific, he wrote. Black rabbits, introduced onto the Falklands back in 1764, had yielded decades worth of variously colored offspring. Clues, clues, clues. What did they signify, how did they fit? The cuckoos of Java versus the cuckoos of Sumatra and the Philippines—species or varieties? He wanted every possible piece of relevant data, whatever the source. He went to the Regent's Park Zoo to see its newly acquired orangutan. He became a greedy amasser of seemingly unconnected facts. He busted his brain to connect them. It was an intense program of research and cogitation, all in hours stolen from his public commitments.

“The changes in species must be very slow,” he figured, not nearly so fast as when domestic breeders select which animals they want to pair. Slow or not, there was a problem to address: When animals continue interbreeding freely, won't the adaptive differences get blurred away? If so, “all the change that has been accumulated cannot be transmitted.” Maybe isolation somehow prevents that. Maybe sterility between different forms, like the sterility of hybrids in domestic breeding, allows the accumulated change to persist. By now he was making some cocky comments in the notebook about “my theory,” although that was premature. His theory hadn't yet coalesced. He was still groping to see the scope of the phenomenon, let alone to find a mechanism that would explain it. “Study the wars of organic being,” he advised himself. Imagine that mankind didn't exist and that monkeys, breeding, improving, eventually produced some sort of alternate intellectual being. Manlike but not Man, and transmuted from four-handed, arboreal animals. That was hard to grasp, sure, but maybe not so much harder than Lyell's idea about slow, incremental processes accounting for all the big effects in geology. Remember the apteryx, Darwin told himself. If New Zealand had been divided into many islands, would there now be many apteryx species?