Bully for Brontosaurus

by Stephen Jay Gould

  5. Retraction. After all this buildup and detail, the denouement can only be described as brief, simple, and conclusive. The further expeditions were blessed with success. Abundant new specimens destroyed Osborn’s dream for two reasons that could scarcely be challenged. First, the new specimens formed a series from teeth worn as profoundly as Hesperopithecus to others of the same species with crown and cusps intact. The diagnostic pattern of the unworn teeth proclaimed pig rather than primate. Second, the unworn teeth could not be distinguished from premolars firmly residing in a peccary’s palate found during a previous expedition. Osborn, who was never praised for a charitable nature, simply shut up and never mentioned Hesperopithecus again in his numerous succeeding articles on human ancestry. He had enjoyed the glory, but he let Gregory take the heat in a forthright retraction published in Science (December 16, 1927):

  Among other material the expedition secured a series of specimens which have led the writer to doubt his former identification of the type as the upper molar of an extinct primate, and to suspect that the type specimen of Hesperopithecus haroldcookii may be an upper premolar of a species of Prosthennops, an extinct genus related to modern peccaries.

  Why should the detractors of science still be drawing such mileage from this simple story of a hypothesis swiftly refuted by science working well? I would divide the reasons into red herrings and a smaller number of allowable points. The red herrings all center on rhetorical peculiarities that anyone skilled in debate could use to advantage. (Debate, remember, is an art form dedicated to the winning of arguments. Truth is one possible weapon, rarely the best, in such an enterprise.) Consider three good lines:

  1. “How can you believe those evolutionists if they can make monkeys out of themselves by calling a pig a monkey?” As a trope of rhetoric, given the metaphorical status of pigs in our culture, the true affinity of Hesperopithecus became a blessing for creationists. What could possibly sound more foolish than the misidentification of a pig as a primate. My side might have been better off if Hesperopithecus had been, say, a deer or an antelope (both members of the order Artiodactyla, along with pigs, and therefore equally far from primates).

  Yet anyone who has studied the dental anatomy of mammals knows immediately that this seemingly implausible mix-up of pig for primate is not only easy to understand but represents one of the classic and recurring confusions of the profession. The cheek teeth of pigs and humans are astonishingly and uncannily similar. (I well remember mixing them up more than once in my course on mammalian paleontology, long before I had ever heard the story of Hesperopithecus.) Unworn teeth can be told apart by details of the cusps, but isolated and abraded teeth of older animals are very difficult to distinguish. The Hesperopithecus tooth, worn so flat and nearly to the roots, was a prime candidate for just such a misidentification.

  A wonderfully ironic footnote to this point was unearthed by John Wolf and James S. Mellett in an excellent article on Nebraska Man that served as the basis for my researches (see bibliography). In 1909, the genus Prosthennops was described by W. D. Matthew, Osborn’s other paleontological colleague at the American Museum of Natural History, and—guess who—the same Harold Cook who would find Hesperopithecus ten years later. They explicitly warned their colleagues about the possible confusion of these peccary teeth with the dentition of primates:

  The anterior molars and premolars of this genus of peccaries show a startling resemblance to the teeth of Anthropoidea, and might well be mistaken for them by anyone not familiar with the dentition of Miocene peccaries.

  2. “How can you believe those evolutionists if they can base an identification on a single worn tooth?” William Jennings Bryan, the wily old lawyer, remarked: “These men would destroy the Bible on evidence that would not convict a habitual criminal of a misdemeanor.”

  My rejoinder may seem like a cavil, but it really isn’t. Harold Cook did send but a single tooth to Osborn. (I do not know why he had not heeded his own previous warning of 1909. My guess would be that Cook played no part in writing the manuscript and that Matthew had been sole author of the statement. An old and admirable tradition grants joint authorship to amateur collectors who often find the material that professionals then exploit and describe. Matthew was the pro, Cook the experienced and sharp-eyed local collector.) Osborn sought comparative material in the Museum’s collection of fossil mammals and located a very similar tooth found in the same geological strata in 1908. He added this second tooth to the sample and based the genus Hesperopithecus on both specimens. (This second tooth had been found by W. D. Matthew, and we must again raise the question of why Matthew didn’t heed his own warning of 1909 about mixing up primates and peccaries. For Osborn showed both teeth to Matthew and won his assent for a probable primate identification. In his original description, Osborn wrote of this second tooth: “The specimen belonged to an aged animal and is so water-worn that Doctor Matthew, while inclined to regard it as a primate, did not venture to describe it.”)

  Thus the old canard about basing a human reconstruction on a single tooth is false. The sample of Hesperopithecus included two teeth from the start. You might say that two is only minimally better than one, and still so far from a whole animal that any conclusion must be risible. Not so. One of anything can be a mistake, an oddball, an isolated peculiarity; two, on the other hand, is the beginning of a pattern. Second specimens always provide a great increment of respect. The Piltdown fraud, for example, did not take hold until the forgers concocted a second specimen.

  3. “How can you believe those evolutionists if they reconstruct an entire man—hair, skin, and all—from a single tooth?” On this issue, Osborn and Gregory were unjustly sandbagged by an over-zealous colleague. In England, G. Elliot Smith collaborated with the well-known scientific artist Amedee Forestier to produce a graphic reconstruction of a Hesperopithecus couple in a forest surrounded by other members of the Snake Creek fauna. Forestier, of course, could learn nothing from the tooth and actually based his reconstruction on the conventional rendering of Pithecanthropus, or Java man.

  The infamous restoration of Hesperopithecus published in the Illustrated London News in 1922. NEG. NO. 2A17487. COURTESY DEPARTMENT OF LIBRARY SERVICES, AMERICAN MUSEUM OF NATURAL HISTORY.

  Forestier’s figure is the one ridiculed and reproduced by creationists, and who can blame them? The attempt to reconstruct an entire creature from a single tooth is absolute folly—especially in this case when the authors of Hesperopithecus had declined to decide whether their creature was ape or human. Osborn had explicitly warned against such an attempt by pointing out how organs evolve at different rates, and how teeth of one type can be found in bodies of a different form. (Ironically, he cited Piltdown as an example of this phenomenon, arguing that, by teeth alone, the “man” would have been called an ape. How prescient in retrospect, since Piltdown is a fraud made of orangutan teeth and a human skull.)

  Thus, Osborn explicitly repudiated the major debating point continually raised by modern creationists—the nonsense of reconstructing an entire creature from a single tooth. He said so obliquely and with gentle satire in his technical article for Nature, complaining that G. E. Smith had shown “too great optimism in his most interesting newspaper and magazine articles on Hesperopithecus.” The New York Times reported a more direct quotation: “Such a drawing or ‘reconstruction’ would doubtless be only a figment of the imagination of no scientific value, and undoubtedly inaccurate.”

  Among the smaller number of allowable points, I can hardly blame creationists for gloating over the propaganda value of this story, especially since Osborn had so shamelessly used the original report to tweak Bryan. Tit for tat.

  I can specify only one possibly legitimate point of criticism against Osborn and Gregory. Perhaps they were hasty. Perhaps they should have waited and not published so quickly. Perhaps they should have sent out their later expedition before committing anything to writing, for then the teeth would have been officially identified as peccaries first,
last, and always. Perhaps they proceeded too rapidly because they couldn’t resist such a nifty opportunity to score a rhetorical point at Bryan’s expense. I am not bothered by the small sample of only two teeth. Single teeth, when well preserved, can be absolutely diagnostic of a broad taxonomic group. The argument for caution lay in the worn and eroded character of both premolars. Matthew had left the second tooth of 1908 in a museum drawer; why hadn’t Osborn shown similar restraint?

  But look at the case from a different angle. The resolution of Hesperopithecus may have been personally embarrassing for Osborn and Gregory, but the denouement was only invigorating and positive for the institution of science. A puzzle had been noted and swiftly solved, though not in the manner anticipated by the original authors. In fact, I would argue that Osborn’s decision to publish, however poor his evidence and tentative his conclusions, was the most positive step he could have taken to secure a resolution. The published descriptions were properly cautious and noncommittal. They focused attention on the specimens, provided a series of good illustrations and measurements, provoked a rash of hypotheses for interpretation, and inspired the subsequent study and collection that soon resolved the issue. If Osborn had left the molar in a museum drawer, as Matthew had for the second tooth found in 1908, persistent anomaly would have been the only outcome. Conjecture and refutation is a chancy game with more losers than winners.

  I have used the word irony too may times in this essay, for the story of Hesperopithecus is awash in this quintessential consequence of human foibles. But I must beg your indulgence for one last round. As their major pitch, modern fundamentalists argue that their brand of biblical literalism represents a genuine discipline called “scientific creationism.” They use the case of Nebraska Man, in their rhetorical version, to bolster this claim, by arguing that conventional science is too foolish to merit the name and that the torch should pass to them.

  As the greatest irony of all, they could use the story of Hesperopithecus, if they understood it properly, to advance their general argument. Instead, they focus on their usual ridicule and rhetoric, thereby showing their true stripes even more clearly. The real message of Hesperopithecus proclaims that science moves forward by admitting and correcting its errors. If creationists really wanted to ape the procedures of science, they would take this theme to heart. They would hold up their most ballyhooed, and now most thoroughly discredited, empirical claim—the coexistence of dinosaur and human footprints in the Paluxy Creek beds near Dallas—and publicly announce their error and its welcome correction. (The supposed human footprints turn out to be either random depressions in the hummocky limestone surface or partial dinosaur heel prints that vaguely resemble a human foot when the dinosaur toe strikes are not preserved.) But the world of creationists is too imbued with irrefutable dogma, and they don’t seem able even to grasp enough about science to put up a good show in imitation.

  I can hardly expect them to seek advice from me. May they, therefore, learn the virtue of admitting error from their favorite source of authority, a work so full of moral wisdom and intellectual value that such a theme of basic honesty must win special prominence. I remind my adversaries, in the wonderful mixed metaphors of Proverbs (25:11,14), that “a word fitly spoken is like apples of gold in pictures of silver…. Whoso boasteth himself of a false gift is like clouds and wind without rain.”

  30 | Justice Scalia’s Misunderstanding

  CHARLES LYELL, defending both his version of geology and his designation of James Hutton as its intellectual father, described Richard Kirwan as a man “who possessed much greater authority in the scientific world than he was entitled by his talents to enjoy.”

  Kirwan, chemist, mineralogist, and president of the Royal Academy of Dublin, did not incur Lyell’s wrath for a mere scientific disagreement, but for saddling Hutton with the most serious indictment of all—atheism and impiety. Kirwan based his accusations on the unlikely charge that Hutton had placed the earth’s origin beyond the domain of what science could consider or (in a stronger claim) had even denied that a point of origin could be inferred at all. Kirwan wrote in 1799:

  Recent experience has shown that the obscurity in which the philosophical knowledge of this [original] state has hitherto been involved, has proved too favorable to the structure of various systems of atheism or infidelity, as these have been in their turn to turbulence and immorality, not to endeavor to dispel it by all the lights which modern geological researches have struck out. Thus it will be found that geology naturally ripens…into religion, as this does into morality.

  In our more secular age, we may fail to grasp the incendiary character of such a charge at the end of the eighteenth century, when intellectual respectability in Britain absolutely demanded an affirmation of religious fealty, and when fear of spreading revolution from France and America equated any departure from orthodoxy with encouragement of social anarchy. Calling someone an atheist in those best and worst of all times invited the same predictable reaction as asking Cyrano how many sparrows had perched up there or standing up in a Boston bar and announcing that DiMaggio was a better hitter than Williams.

  Thus, Hutton’s champions leaped to his defense, first his contemporary and Boswell, John Playfair, who wrote (in 1802) that

  such poisoned weapons as he [Kirwan] was preparing to use, are hardly ever allowable in scientific contest, as having a less direct tendency to overthrow the system, than to hurt the person of an adversary, and to wound, perhaps incurably, his mind, his reputation, or his peace.

  Thirty years later, Charles Lyell was still fuming:

  We cannot estimate the malevolence of such a persecution, by the pain which similar insinuations might now inflict; for although charges of infidelity and atheism must always be odious, they were injurious in the extreme at that moment of political excitement [Principles of Geology, 1830].

  (Indeed, Kirwan noted that his book had been ready for the printers in 1798 but had been delayed for a year by “the confusion arising from the rebellion then raging in Ireland”—the great Irish peasant revolt of 1798, squelched by Viscount Castlereagh, uncle of Darwin’s Captain FitzRoy [see Essay 1 for much more on Castlereagh].)

  Kirwan’s accusation centered upon the last sentence of Hutton’s Theory of the Earth (original version of 1788)—the most famous words ever written by a geologist (quoted in all textbooks, and often emblazoned on the coffee mugs and T-shirts of my colleagues):

  The result, therefore, of our present enquiry is, that we find no vestige of a beginning—no prospect of an end.

  Kirwan interpreted both this motto, and Hutton’s entire argument, as a claim for the earth’s eternity (or at least as a statement of necessary agnosticism about the nature of its origin). But if the earth be eternal, then God did not make it. And if we need no God to fashion our planet, then do we need him at all? Even the weaker version of Hutton as agnostic about the earth’s origin supported a charge of atheism in Kirwan’s view—for if we cannot know that God made the earth at a certain time, then biblical authority is dethroned, and we must wallow in uncertainty about the one matter that demands our total confidence.

  It is, I suppose, a testimony to human carelessness and to our tendency to substitute quips for analysis that so many key phrases, the mottoes of our social mythology, have standard interpretations quite contrary to their intended meanings. Kirwan’s reading has prevailed. Most geologists still think that Hutton was advocating an earth of unlimited duration—though we now view such a claim as heroic rather than impious.

  Yet Kirwan’s charge was more than merely vicious—it was dead wrong. Moreover, in understanding why Kirwan erred (and why we still do), and in recovering what Hutton really meant, we illustrate perhaps the most important principle that we can state about science as a way of knowing. Our failure to grasp the principle underlies much public misperception about science. In particular, Justice Scalia’s recent dissent in the Louisiana “creation science” case rests upon this error in discussing the cha
racter of evolutionary arguments. We all rejoiced when the Supreme Court ended a long episode in American history and voided the last law that would have forced teachers to “balance” instruction in evolution with fundamentalist biblical literalism masquerading under the oxymoron “creation science.” I now add a tiny hurrah in postscript by pointing out that the dissenting argument rests, in large part, upon a misunderstanding of science.

  Hutton replied to Kirwan’s original attack by expanding his 1788 treatise into a cumbersome work, The Theory of the Earth (1795). With forty-page quotations in French and repetitive, involuted justifications, Hutton’s new work condemned his theory to unreadability. Fortunately, his friend John Playfair, a mathematician and outstanding prose stylist, composed the most elegant pony ever written and published his Illustrations of the Huttonian Theory of the Earth in 1802. Playfair presents a two-part refutation for Kirwan’s charge of atheism.

  1. Hutton neither argued for the earth’s eternity nor claimed that we could say nothing about its origin. In his greatest contribution, Hutton tried to develop a cyclical theory for the history of the earth’s surface, a notion to match the Newtonian vision of continuous planetary revolution about the sun. The materials of the earth’s surface, he argued, passed through a cycle of perfect repetition in broad scale. Consider the three major stages. First, mountains erode and their products are accumulated as thick sequences of layered sediments in the ocean. Second, sediments consolidate and their weight melts the lower layers, forming magmas. Third, the pressure of these magmas forces the sediments up to form new mountains (with solidified magmas at their core), while the old, eroded continents become new ocean basins. The cycle then starts again as mountains (at the site of old oceans) shed their sediments into ocean basins (at the site of old continents). Land and sea change positions in an endless dance, but the earth itself remains fundamentally the same. Playfair writes: