Heroes in Nature

Taxonomy, the science of classifying and ordering organisms, has an undeserved reputation as a harmless, and mindless, activity of listing, cataloguing, and describing—consider the common idea of a birdwatcher, up at 5:30 in the morning with his binoculars, short pants, and “life list” of every bird he has seen. Even among fellow scientists, taxonomy is often treated as “stamp collecting,” while its practitioners are viewed much as the Biblical hyraxes—“a feeble folk that dwelleth among the rocks.”

It was not always so. During the eighteenth and early nineteenth centuries, taxonomy was in the forefront of the sciences. The greatest biologists of Europe were professional taxonomists—Linnaeus, Cuvier, Lamarck. Darwin’s major activity during the twenty years separating his Malthusian insights from the publication of his evolutionary theory was a three-volume work on the taxonomy of barnacles. Thomas Jefferson took time out from the affairs of state to publish one of the great taxonomic errors in the history of paleontology—he described a giant sloth claw as a lion three times the size of Africa’s version. These heady days were marked by discovery as naturalists collected the fauna and flora of previously uncharted regions. They were also marked by the emergence of intellectual structure as coherent classifications seemed to mirror the order of God’s thought.

A Species of Eternity is an account of America’s part in this great epoch of natural history. We often forget that 150 years ago much of our continent was as unknown and potentially hazardous as any place on earth. During the eighteenth century, when most naturalists denied the possibility of extinction, explorers expected to find mammoths and other formidable fossil creatures alive in the American West.

Kastner’s theme is discovery and the American frontier. His book is a series of short biographies, chronologically arranged, of the dozen or so passionate, single-minded iconoclasts who fought the hostility of wilderness, and often of urban literary people, to disclose the rich fauna and flora of America. For the most part, they worked alone, with small support from patrons or government. The Lewis and Clark expedition is the only official trip treated here—and its primary purpose was not natural history. We may now look upon tales of frontier toughness and perseverance as the necessary mythology of a nation too young to have real legends. But there is often a residue of truth in such tales, and Kastner’s dozen are among the genuine pioneers.

In his stories about them they appear as eccentric, undaunted. Alexander Wilson walked from New England to Charleston peddling subscriptions to his American Ornithology. Thomas Nuttall seems dottily heroic—oblivious to danger, a Parsifal under a lucky star, vanquishing every Klingsor in the woods, he discovered some of the rarest, most beautiful, and most useful of American plants. We find J.J. Audubon lying and drinking his way across Europe but selling his beautiful pictures of birds to lords and kings. Charles Willson Peale, the great promoter of natural history, was snubbed as an old man and excluded from the ceremonies honoring Lafayette on his triumphal return to Philadelphia in 1824. While Peale stood as a spectator on the steps of Independence Hall Lafayette saw his old companion, rushed over to embrace him, and stood by him through all the official homages. John Lawson, captured by Tuscarora Indians, met the following fate according to an eyewitness: “They stuck him full of fine small splinters or torch-woods like hog’s bristles and so set them gradually afire.” David Douglas fell into a pit trap for wild cattle and was stomped to death by a bull.

Kastner’s book is well written and beautifully produced—as Knopf once did routinely, but now does sporadically. It has generous margins and well chosen, finely screened illustrations, several in color, and is presented frankly as a “celebration” of some extraordinary men. But the book suffers badly because Kastner fails to understand (or at least to express) one of the two essential dimensions of excitement in the science of classification. One, which he well appreciates, is the sheer joy of discovering new things. The other is the intellectual pleasure of constructing an order that teaches us something essential about nature—for Kastner’s heroes, that order lay in the plans of God; for us today, in the workings of evolution. Kastner concentrates almost entirely upon discovery, and seems to hold the dated view that science constructs its theories by the accumulation of unadulterated facts. Good science, in this perspective, is the suppression of speculation and attentiveness to fact. In assessing William Bartram, for example, Kastner writes: “For all his poeticizing, [he] was a true scientist who believed the basis of science was observed fact. Naturalists have found him a remarkably reliable source.”

But isolated facts count for little, and meaning does not accrue simply by extending a list. I would not, as Kastner does, sum up the importance of the Lewis and Clark expedition by printing a two-page list of the new species they found. Science is an interplay of changing theories about the world and its structure. New theories are complex products of creative thinking, changing social circumstances, advances in other fields, daring analogies, and, to be sure, new facts. New facts may disturb old theories, but they do not, by themselves, specify new ones. Rather, they achieve their fullest meaning as exemplifications of theory. If changing theory is the stuff of science, then we cannot understand science by cataloguing new facts. And we cannot grasp the history and meaning of taxonomy by focusing only upon discovery.

In trying to explain the accomplishments of America’s early naturalists, Kastner does little more than praise their perseverance and discuss their new species. His final chapter does not summarize their intellectual achievements or state what their discoveries meant for reassessing the order of nature; instead, it merely presents a picture of one species named for each of them—as though Mark Catesby’s legacy resides in the fact that we call the common bullfrog Rana catesbeiana.

The early naturalists did not just gather new species, and taxonomy does not progress simply by adding new items, any more than science progresses by the simple accumulation of information. These men sought the message revealed dimly in the similarities and differences among organisms. We trivialize what they did, and degrade the source of their passion, if we view their accomplishment so largely as a matter of finding new species. I fear that Kastner, in failing to understand that taxonomy seeks the causes of order, has also failed to order his subjects by any criterion other than the record of discovery. He tells fascinating stories, but he might have done much more than that.

Why, then, was taxonomy such a vivid subject during the period Kastner treats? In part, the answer is suggested by some of the background Kastner supplies: unknown plants and animals were streaming into Europe from all over the world. Many were useful as medicines or foods; others were simply beautiful in gardens. But the promise of adding to a list is not enough to inspire the best thinkers. The great taxonomists felt that they finally had sufficient information to apprehend and explain nature’s order. This was Linnaeus’s vision, not one of pigeonholing, but of insight into the why of things.

Kastner portrays the Linnaean system as a form of superior bookkeeping, Linnaeus himself as an arbiter and allocator: “His method was invaluable to science at the time, the best tool yet devised for a natural historian. It imposed an orderly system and was adaptable for the amateur as well as the professional.” But Linnaeus played for much higher stakes—a quest for the “natural system” and its promise of a glimpse into God’s mind itself. As Louis Agassiz, America’s greatest naturalist, put it: taxonomy is the noblest and most sublime of all sciences; for each species is an idea in the mind of God. If we can understand how these ideas are ordered, we may come as close as science can to apprehending the workings of divinity.

Darwin turned the world about, but he maintained the vision that taxonomy could display the causes of order—it could show descent and genealogy rather than divine plan. Some naturalists, he wrote in the Origin of Species, view taxonomy as

a scheme for arranging together those living objects which are most alike, and for separating those which are most unlike; or as an artificial method of enunciating…. But many naturalists think that something more is meant by the Natural System…. I believe that this is the case, and that community of descent—the one known cause of close similarity in organic beings—is the bond, which is partially revealed to us by our classifications.

All the great taxonomists railed against a natural history that sought only to describe and discover new species. Lamarck wrote: “In vain do naturalists consume their time in describing new species, in seizing upon every nuance and slight peculiarity to enlarge the immense list of inscribed species…. If philosophy of science is neglected, its progress will be without reality and its work will forever remain incomplete.” Ernst Haeckel reserved his greatest scorn for a purely descriptive approach to natural history: “Today, unfortunately, scientific morphology is more a confused pile of stones than an inhabitable building. And this pile of stones will never become a building as long as scientists only examine each stone, scrutinize it, describe it, figure it, name it, and then throw it down again…. Only when the consideration of form raises itself to explaining, only when the laws of construction are extracted from the variegated chaos of forms, only then will the lowly art of morphography be transformed into the sublime science of morphology” (Generelle Morphologie, 1866).

The great American naturalists also sought to explain and synthesize. As Kastner mentions, Cadwallader Colden tried to outdo Newton in finding the causes of gravitation. Samuel Latham Mitchill took on Joseph Priestley and argued against his chemical doctrine of phlogiston. Even Constantine Rafinesque, the most obsessed searcher for new species, had dreams of synthesis. He published a long poem arguing that instability was as much a law of nature as attraction or gravitation.

It is true that most grand theories fail; while a well-described species endures. If we judge scientists of the past by today’s standards of validity, then we may exalt the mindless but accurate describers. But we would also misrepresent the sources of excitement and change in science. The price of thinking big is flopping hard, but where would we be if scientists only worked at Haeckel’s stoneheap?

I write now on the island of Great Inagua, among the most remote of the Bahamas. Yesterday, my colleague and I found something that we had sought for five years. We are studying a land snail named Cerion, famous among conchologists. Cerion is divided into some 600 “species,” nearly all invalid because any two forms interbreed when their geographical ranges overlap. No one had ever found a pair of species living in the same area without interbreeding over a long period of time. But we have now confirmed the first case of truly separate species within Cerion—Cerion rehderi and Cerion rubicundum live close together, one in crevices and underground, the other hanging on bushes, fifteen miles east of human habitation on the south coast of Inagua. Our own small adventures in making this find—a punctured tire, a leaky radiator—seem derisory when one considers Nuttall exploring a new world filled with real dangers. But there is no excitement quite like new discovery, nothing so unambiguously and totally satisfying; in Kastner’s book one can glimpse the special intensity of such experiences in the early nineteenth century.