The Reluctant Mr. Darwin (18 page)

The littler book, Darwin's abominated volume, has a more complicated editorial history. Let's say you've decided to read or to reread
The Origin of Species
. Immediately you face another decision: Which
Origin
? Six different editions appeared in England during his lifetime, each of the latter five showing revisions by the author. Many of those revisions were substantive. Sentences were added and others cut, passages were rewritten for clarity, second thoughts replaced first thoughts and then third thoughts replaced those, qualifications were inserted, fudges were factored, whole blocks of new argument answered criticisms of the more astute reviewers. Another literary scholar, Morse Peckham, assembled all the changes made throughout sequential editions into a “variorum text” of
The Origin
, published in 1959 on the book's centenary. From Peckham we know, for instance, that for the hurried second edition demanded by John Murray after the sellout, 9 sentences were dropped, 30 were added, and 483 received some tinkering. To the third edition, in 1861, Darwin attached what he called “An Historical Sketch of the Recent Progress of Opinion on the Origin of Species”—that is, a survey of his intellectual predecessors—in response to accusations that he was taking credit for ideas that others had published before him. This sketch, placed as a preface, acknowledged earlier thinking by Lamarck, Geoffroy, his old Edinburgh mentor Robert Grant, the still anonymous author of
Vestiges
, the anatomist Richard Owen, an obscure writer on shipbuilding timber named Patrick Matthew (who'd gotten jealously miffed over Darwin's natural selection, insisting he'd mentioned the same idea back in 1831), and his own grandfather Erasmus, among others.

For the fourth edition, in 1866, Darwin added two pages of further credits to the historical sketch and expanded the main text by 10 percent, including an enlarged section on embryology and development. The fifth edition was the first in which Darwin adopted Herbert Spencer's famous phrase, “the Survival of the Fittest,” as a rough synonym for natural selection. All these later editions incorporated more supporting facts and examples, some drawn from the recent work of scientists inspired by
The Origin
itself as the cycle of evolutionary theory and research began to turn round. Darwin's text was evolving, adapting, in reaction to the ongoing debate it had triggered. For the sixth edition he included a whole new chapter, “Miscellaneous Objections,” answering one of his most aggressive critics point by point. This was the edition, too, for which Darwin struck the word “On” from his title, so that
On the Origin of Species by Means of Natural Selection
could henceforth be accurately shortened, in casual speech, to
The Origin of Species
.

The sixth edition, published by Murray in 1872, was the last worked on by Darwin himself, and for that reason has often been taken as the authoritative text, the one people should read if they want to know what Darwin
really, finally
meant to say. In my non-expert opinion, this is misguided. The last version wasn't necessarily the best, the most interesting, or the most significant. It wasn't even, to revert to that problematic word, the most “Darwinian.” Not all the changes Darwin made to
The Origin
between 1859 and 1872 were improvements, and not all his improvements were as consequential as what he'd said, most daringly, in the book as first published. After thirteen years of extraordinary international hubbub, its main ideas had become widely known, from secondhand reportage and literary chatter as well as from the text itself. Those ideas were now swirling throughout the scientific communities of Britain, continental Europe, and America, and swirling also (more blurrily) in the public awareness, independent of whatever subtle revisions Mr. Darwin made for his latest edition. Evolution by natural selection was, by 1872, a bigger intellectual phenomenon than
The Origin of Species
, whereas in November 1859 the book was (with all due respect to Wallace) the definitive embodiment of the theory. Fiddle as he might with refinements, rebuttals, and adjustments of emphasis, Darwin wasn't perfecting or undoing what he had initially done, which was to startle the world with a new way of seeing life on Earth.

So my advice is, ignore the afterthoughts. Ignore the paperback reprints of the sixth edition. Trust no one; before you buy, before you read, check the small print in front under “Note on the Text,” or the discreet line of dating opposite the title page. Whether you turn to
The Origin of Species
as a scientific work or as a historical and literary document, do yourself and Charles Darwin a favor: Find a reprint (preferably a facsimile reprint, with the original typeface and pagination) of the first edition. That's the book, with all its courageous freshness and its flaws, that provoked the most cataclysmic change in human thinking within the past four hundred years.

33

The book opens in a mild, unassuming tone of reminiscence:

The passage reads easily but there's much alluded to: biogeography, paleontology, closely allied species adjacent in time. For the “mystery of mysteries” phrase from John Herschel, Darwin had dipped back into his transmutation notebook “E,” using an entry he'd made as an excited young man in December 1838. The part about throwing “some light” is a whopping understatement, which he will repeat to good effect, even more whoppingly understated, at the end of the book. Beyond touching those points, his other smart choice here is to come sailing into view—offering himself to our first impression—aboard the
Beagle
. It makes him seem personable and grounded in experience; back in 1859, it also reminded readers that this middle-aged theorist was the same fellow who, twenty years earlier, had delivered the popular travel narrative,
Journal of Researches
.

Darwin's six-page introduction, begun with that sentence, is a sort of overture in which he sounds his major themes: that “innumerable species inhabiting this world have been modified,” giving them amazing “perfection of structure and coadaptation,” and that the mechanism he calls “natural selection” can account for those modifications. He doesn't use the word “evolution.” (That term appears nowhere in the first edition, though Darwin does conclude the book's very last sentence by saying that many wondrous species “have been, and are being, evolved.”) The old, familiar, and provocative word “transmutation” is omitted here, too. Instead he talks in these opening pages about “modification and coadaptation” (and, later in the book, about “descent with modification” or his “theory of descent”). The other important theme announced in his introduction is the “struggle for existence,” the same phrase for the same idea that Alfred Wallace hit upon independently. And of course he mentions Malthus.

Then he writes:

Add just two further ideas—that continued selection leads to prodigious extremes of adaptation, and also eventually to divergence of lineages—and this could stand as the abstract of the abstract.

The main text is divided into fourteen chapters. The peculiar sequence of those chapters reflects a counterintuitive decision by Darwin: to discuss the mechanism by which evolution occurs before calling attention to the consequent phenomena. That is, he works first to persuade readers about natural selection—that it
can
happen and
must
happen, given variation and the struggle for existence. Only afterward does he offer evidence showing that evolution itself, by whatever mechanism,
has
happened. This may seem backward to us, but in 1859 it was shrewd, given that species transmutation was a familiar idea that had been proposed and rejected previously, whereas natural selection was the breakthrough concept that could make transmutation plausible, even irresistible, to skeptics.

Darwin devotes his first chapter to variation among domestic animals and plants, noting how much of it routinely occurs, and how breeders use such small differences to transform lineages of livestock, pets, and crops. Dogs, cows, pigs, goats, strawberries, potatoes, dahlias, hyacinths, rabbits, sheep, horses, ducks—every domesticated species encompasses variation. One chicken, if you know your birds, is not quite like another. A good pig differs from a mediocre pig. And so also, of course, with pigeons—especially fancy pigeons, his favorite case. Drawing on the expertise gleaned from his own coops, his esoteric reading, and the London fanciers' clubs he occasionally visited, Darwin argues that all pigeon breeds—the tumbler, the fantail, the pouter, and many others—are descended from one species of wild dove,
Columba livia
. What explains their extravagant forms of differentiation? The answer is selection, as practiced by humans. What explains racehorses versus dray horses, greyhounds versus bloodhounds? Again, selection by breeders. Nature somehow provides the small variations. Humans select preferred variations when they pair their animals or pollinate their plants. Those preferred variations are perpetuated—and magnified, through accumulation—over generations of domestic breeding. The result is specialized forms, differing from their ancestors in ways that people find useful or amusing.
Artificial
selection: the first leg of Darwin's cardinal analogy.

Then he turns to variation in the wild. “No one supposes that all the individuals of the same species are cast in the very same mould,” he says. Anyone who looks closely will admit that wild animals within any species, like domestics, differ slightly from one another. Wallace saw it among his boxes of beetles, birds, and butterflies collected for sale. Darwin saw it among his infernal barnacles. Variation is exactly what made taxonomy so damned difficult. But most people in 1859 assumed that such differences, among wild creatures, are limited and evanescent. Other naturalists besides Darwin and Wallace had noticed them, but considered them unimportant. If species are immutable, according to this view, then variations are minor wobbles around the archetypal essence of each species, to which every digression will eventually return. Varieties within a species are populations of such wobblers, insignificant and impermanent anomalies constrained by uncrossable boundaries of species identity.

No, it isn't so, says Darwin. Varieties can't be so easily dismissed. In fact, even defining the two words—“species” and “variety”—is a tricky task. The tricky part is distinguishing one of those categories from the other, and the hardest thing about classifying specimens within such a category is that sometimes ambiguity can't be resolved. Lines blur. Taxonomists disagree. One botanist will look at a large group of plants and see 251 species; another expert will look at the same group and see only 112 species, plus 139 false or trivial distinctions. From his Galápagos experience and the trouble afterward in classifying the birds, Darwin remembers being “much struck how entirely vague and arbitrary is the distinction between species and varieties.” The real distinction, he concludes, is this: a difference in degree. Species within a genus differ more than—but in the same ways as—varieties within a species do. The minor differences between varieties can accumulate, until they become the major differences between one species and another. It's the very point that headlined Wallace's 1858 paper, “On the Tendency of Varieties to Depart Indefinitely from the Original Type.” Darwin didn't need to see that paper (and he certainly didn't want to) because he had arrived at the same insight himself.

These opening chapters represent Darwin's direct assault on the old mode of thinking, which held species to be divinely created and fixed, like ideas stored in the file cabinet of God. The two chapters lay a groundwork for his discussion of natural selection, but they do more. They deliver one of his most profound contributions to scientific thought. As the population geneticist Richard Lewontin has lately written: “Darwin revolutionized our study of nature by taking the actual variation among actual things as central to the reality, not as an annoying and irrelevant disturbance to be wished away.” He allowed us to see the living world as endlessly various. He helped us understand the whole physical universe as a realm of concrete contingencies, not imperfectly represented ideals.

Chapter III is his treatment of the struggle for existence, using Malthusian arithmetic and empirical data to dispel the notion of nature in a state of divinely ordered tranquility. Nature's real order
isn't
peaceable; it's a desperate scramble, even when the desperation is muted and obscure. Darwin alludes to a famous statement by the Swiss botanist A.-P. de Candolle, suggesting that “all nature is at war, one organism with another, or with external nature.” Predation, competition, parasitism, overcrowding. As species continue to procreate, there just isn't enough food or enough space for their offspring. Reproductive rates are geometric. Habitat is finite. Fortunately, many dangers loom. If struggle and death didn't sweep away most individuals of most species, the lands, seas, and skies would be impossibly full. Humans are relatively slow breeders, but the arithmetic holds true even for us: If we all bred and survived, doubling our population every generation, within a few thousand years there wouldn't be standing room for another person on the planet. Elephants breed even more slowly. But their inherent rate of increase is geometric, too. A single female elephant, if she produced just six offspring in her lifetime, and if every descendant reproduced similarly, would in five centuries (according to Darwin's rough calculation) yield a population of 15 million. That's a lot of elephants. Too many. It doesn't happen. Why not? Because every elephant must struggle—to survive, to reproduce—and many fail.