Bully for Brontosaurus

by Stephen Jay Gould

  On February 26, 1922, Bryan published an article in the Sunday New York Times to further his legislative campaign against the teaching of evolution. Bryan, showing some grasp of the traditional parries against Darwin, but constantly confusing doubts about the mechanism of natural selection with arguments against the fact of evolution itself, rested his case upon a supposed lack of direct evidence for the claims of science:

  The real question is, Did God use evolution as His plan? If it could be shown that man, instead of being made in the image of God, is a development of beasts we would have to accept it, regardless of its effect, for truth is truth and must prevail. But when there is no proof we have a right to consider the effect of the acceptance of an unsupported hypothesis.

  The Times, having performed its civic duty by granting Bryan a platform, promptly invited Osborn to prepare a reply for the following Sunday. Osborn’s answer, published on March 5 and reissued as a slim volume by Charles Scribner’s Sons under the title Evolution and Religion, integrated two arguments into a single thesis: The direct, primarily geological evidence for evolution is overwhelming, and evolution is not incompatible with religion in any case. As a motto for his approach, and a challenge to Bryan from a source accepted by both men as unimpeachable, Osborn cited a passage from Job (12:8): “…speak to the earth, and it shall teach thee.” When, on the eve of the Scopes trial, Osborn expanded his essay into a longer attack on Bryan, he dedicated the new book to John Scopes and chose a biting parody of Job for his title—The Earth Speaks to Bryan (Charles Scribner’s Sons, 1925).

  When a man poses such a direct challenge to an adversary, nothing could possibly be more satisfying than a quick confirmation from an unanticipated source. On February 25, 1922, just the day before Bryan’s Times article, Harold J. Cook, a rancher and consulting geologist, had written to Osborn:

  I have had here, for some little time, a molar tooth from the Upper, or Hipparion phase of the Snake Creek Beds, that very closely approaches the human type…. Inasmuch as you are particularly interested in this problem and, in collaboration with Dr. Gregory and others, are in the best position of anyone to accurately determine the relationships of this tooth, if it can be done, I will be glad to send it on to you, should you care to examine and study it.

  In those bygone days of an efficient two-penny post, Osborn probably received this letter on the very morning following Bryan’s diatribe or, at most, a day or two later. Osborn obtained the tooth itself on March 14, and, with his usual precision (and precisely within the ten-word limit for the basic rate), promptly telegraphed Cook: “Tooth just arrived safely. Looks very promising. Will report immediately.” Later that day, Osborn wrote to Cook:

  The instant your package arrived, I sat down with the tooth, in my window, and I said to myself: “It looks one hundred per cent anthropoid.” I then took the tooth into Dr. Matthew’s room and we have been comparing it with all the books, all the casts and all the drawings, with the conclusion that it is the last right upper molar tooth of some higher Primate…. We may cool down tomorrow, but it looks to me as if the first anthropoid ape of America has been found.

  But Osborn’s enthusiasm only warmed as he studied the tooth and considered the implications. The human fossil record had improved sufficiently to become a source of strength, rather than an embarrassment, to evolutionists, with Cro-Magnon and Neanderthal in Europe (not to mention the fraudulent Piltdown, then considered genuine and strongly supported by Osborn) and Pithecanthropus (now called Homo erectus) in East Asia. But no fossils of higher apes or human ancestors had ever been found anywhere in the Americas. This absence, in itself, posed no special problem to evolutionists. Humans had evolved in Asia or Africa, and the Americas were an isolated world, accessible primarily by a difficult route of migration over the Bering land bridge. Indeed, to this day, ancient humans are unknown in the New World, and most anthropologists accept a date of 20,000 years or considerably less (probably more like 11,000) for the first peopling of our hemisphere. Moreover, since these first immigrants were members of our stock, Homo sapiens, no ancestral species have ever been found—and none probably ever will—in the Americas.

  Still, an American anthropoid would certainly be a coup for Osborn’s argument that the earth spoke to Bryan in the language of evolution, not to mention the salutary value of a local product for the enduring themes of hoopla, chauvinism, and flag-waving.

  Therefore, Osborn’s delight—and his confidence—in this highly worn and eroded molar tooth only increased. Within a week or two, he was ready to proclaim the first momentous discovery of a fossil higher primate, perhaps even a direct human ancestor, in America. He honored our hemisphere in choosing the name Hesperopithecus, or “ape of the western world.” On April 25, less than two months after Bryan’s attack, Osborn presented Hesperopithecus in two simultaneous papers with the same title and different content: one in the prestigious Proceedings of the National Academy of Sciences; the other, containing figures and technical descriptions, in the Novitates of the American Museum of Natural History—“Hesperopithecus, the First Anthropoid Primate Found in America.”

  Hesperopithecus was good enough news in the abstract, but Osborn particularly exulted in the uncannily happy coincidences of both time and place. Cook had probably written his letter at the very moment that the compositors were setting Bryan’s oratory in type. Moreover, for the crowning irony, Hesperopithecus had been found in Nebraska—home state of the Great Commoner! If God had permitted a paleontologist to invent a fossil with maximal potential to embarrass Bryan, no one could have bettered Hesperopithecus for rhetorical impact. Needless to say, this preciously ironical situation was not lost on Osborn, who inserted the following gloat of triumph into his article for the staid Proceedings—about as incongruous in this forum as the erotic poetry of the Song of Songs between Ecclesiastes and Isaiah.

  It has been suggested humorously that the animal should be named Bryopithecus after the most distinguished Primate which the State of Nebraska has thus far produced. It is certainly singular that this discovery is announced within six weeks of the day (March 5, 1922) that the author advised William Jennings Bryan to consult a certain passage in the Book of Job, “Speak to the earth and it shall teach thee,” and it is a remarkable coincidence that the first earth to speak on this subject is the sandy earth of the Middle Pliocene Snake Creek deposits of western Nebraska.

  Old Robert Burns certainly knew his stuff when he lamented the frequent unraveling of the best laid plans of mice and men. Unless you browse in the marginal genre of creationist tracts, you will probably not have encountered Hesperopithecus in anything written during the past fifty years (except, perhaps, as a cautionary sentence in a textbook or a paragraph on abandoned hopes in a treatise on the history of science). The reign of Hesperopithecus was brief and contentious. In 1927, Osborn’s colleague William King Gregory, the man identified in Cook’s original letter as the best-qualified expert on primate teeth, threw in the towel with an article in Science: “Hesperopithecus Apparently not an Ape nor a Man.” Expeditions sent out by Osborn in the summers of 1925 and 1926 to collect more material of Hesperopithecus, and to test the hypothesis of primate affinity, had amassed a large series to complement the original tooth. But this abundance also doomed Osborn’s interpretation—for the worn and eroded Hesperopithecus tooth, when compared with others in better and more diagnostic condition, clearly belonged not to a primate but to the extinct peccary Prosthennops.

  One can hardly blame modern creationists for making hay of this brief but interesting episode in paleontology. After all, they’re only getting their fair licks at Osborn, who used the original interpretation to ridicule and lambaste their erstwhile champion Bryan. I don’t think I have ever read a modern creationist tract that doesn’t feature the tale of “Nebraska Man” in a feint from our remarkable record of genuine human fossils, and an attempted KO of evolution with the one-two punch of Piltdown and Hesperopithecus. I write this essay to argue that Nebraska man
tells a precisely opposite tale, one that should give creationists pause (though I do admit the purely rhetorical value of a proclaimed primate ancestor later exposed as a fossil pig).

  The story of Hesperopithecus was certainly embarrassing to Osborn and Gregory in a personal sense, but the sequence of discovery, announcement, testing, and refutation—all done with admirable dispatch, clarity, and honesty—shows science working at its very best. Science is a method for testing claims about the natural world, not an immutable compendium of absolute truths. The fundamentalists, by “knowing” the answers before they start, and then forcing nature into the straitjacket of their discredited preconceptions, lie outside the domain of science—or of any honest intellectual inquiry. The actual story of Hesperopithecus could teach creationists a great deal about science as properly practiced if they chose to listen, rather than to scan the surface for cheap shots in the service of debate pursued for immediate advantage, rather than interest in truth.

  When we seek a textbook case for the proper operation of science, the correction of certain error offers far more promise than the establishment of probable truth. Confirmed hunches, of course, are more upbeat than discredited hypotheses. Since the worst traditions of “popular” writing falsely equate instruction with sweetness and light, our promotional literature abounds with insipid tales in the heroic mode, although tough stories of disappointment and loss give deeper insight into a methodology that the celebrated philosopher of science Karl Popper once labeled as “conjecture and refutation.”

  Therefore, I propose that we reexamine the case of Nebraska Man, not as an embarrassment to avoid in polite company, but as an exemplar complete with lessons and ample scope for the primary ingredient of catharsis and popular appeal—the opportunity to laugh at one’s self. Consider the story as a chronological sequence of five episodes:

  1. Proposal. Harold Cook’s fossil tooth came from a deposit about 10 million years old and filled with mammals of Asiatic ancestry. Since paleontologists of Osborn’s generation believed that humans and most other higher primates had evolved in Asia, the inclusion of a fossil ape in a fauna filled with Asian migrants seemed entirely reasonable. Osborn wrote to Cook a month before publication:

  The animal is certainly a new genus of anthropoid ape, probably an animal which wandered over here from Asia with the large south Asiatic element which has recently been discovered in our fauna…. It is one of the greatest surprises in the history of American paleontology.

  Osborn then announced the discovery of Hesperopithecus in three publications—technical accounts in the American Museum Novitates (April 25, 1922) and in the British journal Nature (August 26, 1922), and a shorter notice in the Proceedings of the National Academy of Sciences (August 1922, based on an oral report delivered in April).

  2. Proper doubt and statement of alternatives. Despite all the hoopla and later recrimination, Osborn never identified Hesperopithecus as a human ancestor. The tooth had been heavily worn during life, obliterating the distinctive pattern of cusps and crown. Considering both this extensive wear and the further geological erosion of the tooth following the death of its bearer, Osborn knew that he could make no certain identification. He did not cast his net of uncertainty widely enough, however, for he labeled Hesperopithecus as an undoubted higher primate. But he remained agnostic about the crucial issue of closer affinity with the various ape branches or the human twig of the primate evolutionary tree.

  Osborn described the tooth of Hesperopithecus as “a second or third upper molar of the right side of a new genus and species of anthropoid.” Osborn did lean toward human affinity, based both on the advice of his colleague Gregory (see point three below) and, no doubt, on personal hope and preference: “On the whole, we think its nearest resemblances are with…men rather than with apes.” But his formal description left this crucial question entirely open:

  An illustration from Osborn’s article of 1922, showing the strong similarity between worn teeth of Hesperopithecus and modern humans. NEG. NO. 2A17804. COURTESY DEPARTMENT OF LIBRARY SERVICES, AMERICAN MUSEUM OF NATURAL HISTORY.

  The Hesperopithecus molar cannot be said to resemble any known type of human molar very closely. It is certainly not closely related to Pithecanthropus erectus in the structure of the molar crown…. It is therefore a new and independent type of Primate, and we must seek more material before we can determine its relationships.

  3. Encouragement of further study. If Osborn had been grandstanding with evidence known to be worthless or indecipherable, he would have made his public point and then shut up after locking his useless or incriminating evidence away in a dark drawer in the back room of a large museum collection. Osborn proceeded in exactly the opposite way. He did everything possible to encourage further study and debate, hoping to resolve his own strong uncertainties. (Osborn, by the way, was probably the most pompous, self-assured S.O.B. in the history of American paleontology, a regal patrician secure in his birthright, rather than a scrappy, self-made man. He once published a book devoted entirely to photographs of his medals and awards and to a list of his publications; as an excuse for such vanity, he claimed that he harbored only a selfless desire to inspire young scientists by illustrating the potential rewards of a fine profession. “Osborn stories” are still told by the score wherever vertebrate paleontologists congregate. And when a man’s anecdotes outlive him by more than half a century, you know that he was larger than life. Thus, the real news about Hesperopithecus must be that, for once, Osborn was expressing genuine puzzlement and uncertainty.)

  In any case, Osborn reached out to colleagues throughout the world. He made numerous casts of Hesperopithecus and sent them to twenty-six universities and museums in Europe and North America. As a result, he was flooded with alternative interpretations from the world’s leading paleoanthropologists. He received sharp criticisms from both sides: from Arthur Smith Woodward, describer of Piltdown, who thought that Hesperopithecus was a bear (and I don’t mean metaphorically), and from G. Elliot Smith, another “hero” of Piltdown, who became too enthusiastic about the humanity of Osborn’s tooth, causing considerable later embarrassment and providing creationists with their “hook.” Osborn tried to rein both sides in, beginning his Nature article with these words:

  Every discovery directly or indirectly relating to the prehistory of man attracts world-wide attention and is apt to be received either with too great optimism or with too great incredulity. One of my friends, Prof. G. Elliot Smith, has perhaps shown too great optimism in his most interesting newspaper and magazine articles on Hesperopithecus, while another of my friends, Dr. A. Smith Woodward, has shown too much incredulity.

  Moreover, Osborn immediately enlisted his colleague W. K. Gregory, the acknowledged local expert on primate teeth, to prepare a more extensive study of Hesperopithecus, including a formal comparison of the tooth with molars of all great apes and human fossils. Gregory responded with two detailed, technical articles, both published in 1923 with the collaboration of Milo Hellman.

  Gregory followed Osborn in caution and legitimate expression of doubt. He began his first article by dividing the characters of the tooth into three categories: those due to wear, to subsequent erosion, and to the genuine taxonomic uniqueness of Hesperopithecus. Since the first two categories, representing information lost, tended to overwhelm the last domain of diagnostic biology, Gregory could reach no conclusion beyond a basic placement among the higher primates:

  The type of Hesperopithecus haroldcookii represents a hitherto unknown form of higher primates. It combines characters seen in the molars of the chimpanzee, of Pithecanthropus, and of man, but, in view of the extremely worn and eroded state of the crown, it is hardly safe to affirm more than that Hesperopithecus was structurally related to all three.

  In the second and longer article, Gregory and Hellman stuck their necks out a bit more—but in opposite directions. Hellman opted for the human side; Gregory for affinity with “the gorilla-chimpanzee group.”

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bsp; 4. Gathering of additional data. Osborn knew, of course, that a worn and eroded tooth would never resolve the dilemma of Hesperopithecus, no matter how many casts were made or how many paleontologists peered down their microscopes. The answers lay in more data buried in the sands of Nebraska, and Osborn pledged, in his diatribe against Bryan, to make the earth speak further:

  What shall we do with the Nebraska tooth? Shall we destroy it because it jars our long preconceived notion that the family of manlike apes never reached the Western world, or shall we endeavor to interpret it, to discover its real relationship to the apes of Asia and of the more remote Africa. Or shall we continue our excavations, difficult and baffling as they are, in the confident hope, inspired by the admonition of Job, that if we keep on speaking to the earth we shall in time have a more audible and distinct reply [from The Earth Speaks to Bryan, p. 43].

  To his professional audiences in Nature, Osborn made the same pledge with more detail: “We are this season renewing the search with great vigor and expect to run every shovelful of loose river sand which comprises the deposit through a sieve of mesh fine enough to arrest such small objects as these teeth.”

  Thus, in the summers of 1925 and 1926, Osborn sent a collecting expedition, led by Albert Thomson, to the Snake Creek beds of Nebraska. Several famous paleontologists visited the site and pitched in, including Barnum Brown, the great dinosaur collector; Othenio Abel of Vienna (a dark figure who vitiated the memory of his fine paleontological work by later activity in the Austrian Nazi party); and Osborn himself. They found abundant material to answer their doubts. The earth spoke both audibly and distinctly, but not in the tones that Osborn had anticipated.