The Flamingo’s Smile

by Stephen Jay Gould

  This principle of early experimentation and later standardization dictates a general reduction of variation—particularly the elimination of extremes. We often misunderstand the reason for a loss of extremes because we try to interpret the disappearance of oddities as a trend in its own right and not as an inevitable consequence of decreasing variation within a natural system. Essay 14 on the disappearance of .400 hitters in baseball considers another example of the same process. Conventional explanations for this most striking and widely discussed trend in baseball invariably look for some directional change—introduction of relief pitching or more grueling schedules composed mostly of night games—that would diminish high hitting alone. But I reasoned that the decline of high hitting may simply reflect the stabilization and general perfection of play that must accompany a game as its standards rise (analogous to the reduction of body plans as successful designs predominate in life’s history). As pitching, fielding, and hitting all improve, variation in each category decreases. I was able to show that league averages have not changed between the great era of .400 hitting (1890–1920) and today, but that both highest averages (the .400 hitters) and lowest averages have converged toward the league average. In other words, extremes have been eliminated at both ends—the same principle of early experimentation (or toleration) and later standardization.

  The second explanation is unconventional and based on random processes. A pattern of shift from few species in many groups to many species in fewer groups would occur even under regimes of random extinction, provided that we allow greater average change per event of speciation early in the history of life (as seems warranted in an initially “empty” world open to almost any experiment in form).

  Extinction, as ecoactivists remind us, is forever. Once we lose a complex experiment in form, it will not arise again; the mathematical odds are too strongly against such a repetition of numerous complex steps (biologists refer to this principle as “the irreversibility of evolution”). Thus, inevitably, we lose most of the early experiments and begin to fill our oceans with repeated examples of the few surviving major groups. Intrigued as I am by random processes, I doubt that they will explain our entire pattern of reduction in body plans, if only because the idea of early experimentation and later standardization makes so much sense. But I would urge that the predictable consequences of random processes be granted much more attention than they usually receive. Random processes do produce high degrees of order—and the existence of pattern is no argument against randomness.

  We live in a world of history and change. As creatures of habit who feel comforted by the discovery of order, we search for principles that grant time a direction—that admit a bit of order into the buzzing and blooming confusion of history. But arrows of time are hard to find and science hasn’t given us many. The second law of thermodynamics, with its increasing entropy and decreasing order in closed systems, is our most famous agent of direction. Most proposals from evolutionary biology are spurious and based more on our hopes and expectations than the workings of natural selection—the notion of continual progress in particular. But this principle of diversity—early experimentation and later standardization—may be a true mark of history, producing trends towards decreased variation in basic designs of life. We should therefore care about conodonts, even if we have never correlated a rock or tend to look askance at inch-long worms with faint tail fins and bilobed heads. For their age, their taxonomic uniqueness, and their demise may record the nature of history.

  5 | Politics and Progress

  17 | To Show An Ape

  TODAY, WE CLASSIFY all humans in a single species, Homo sapiens. But Carolus Linnaeus, in the founding document of animal taxonomy, the Systema Naturae (System of Nature) of 1758, recognized a second species, Homo troglodytes. While Linnaeus devoted several pages to Homo sapiens in all our diversity, Homo troglodytes merited only a paragraph. This second species, active only at night and speaking in hisses, offered little information to back up its existence. Homo troglodytes emerged as a compound of exaggerated travelers’ reports based on imperfect observations of anthropoid apes humanized or native peoples degraded. Linnaeus even ventured the possibility of a third species, Homo caudatus, or man with a tail, but he admitted that this creature, incola orbis antarctici (an inhabitant of the antarctic regions), remained so obscure (if it existed at all) that he could not determine “whether it belongs to the human or monkey genus.”

  Why did this sober naturalist include such poorly supported fiction in the description of his first and most important genus? As a basic answer, Linnaeus worked with a theory that anticipated such creatures; when something should exist anyway, imperfect evidence becomes more acceptable.

  I often write about the interaction of theory and fact in these essays because no other theme so well displays the human side of science—the intrusion of mind into nature and their necessary interpenetration in all creative activity. Science does not follow a one-way path from yielding nature to objective mind. This theme also illustrates why we must abandon as bankrupt the common procedure of judging past scientists by their accuracy according to present knowledge. Some incorrect theories, as grand and generous syntheses of knowledge, pose large and exciting questions, and may thereby produce as many new discoveries as notions that we accept today (see essay 6 in Hen’s Teeth and Horse’s Toes on James Hutton’s use of final causes).

  In this case, an incorrect theory, the chain of being, led Linnaeus to expect intermediate forms between apes and humans. For the objects of nature formed a single chain stretching without a break from the simplest amoeba to us. But the chain of being had always faced a substantial empirical problem—large and apparent gaps between major units, in particular, minerals and plants, plants and animals, monkeys and humans (see essay 18 for a further discussion of this problem). Indeed, Sir Thomas Browne, in his Religio Medici (1642), had declared that the gaps increased as we mounted the scale:

  There is in this Universe a Stair, or manifest Scale of creatures, rising not disorderly, but with a comely method and proportion. Between creatures of mere existence, and things of life, there is a large disproportion of nature; between plants and animals or creatures of sense, a wider difference; between them and Man, a far greater: and if the proportion hold on, between Man and Angels there should be yet a greater.

  For those dedicated to filling the gaps, the apparent distance between monkey and human posed the greatest resolvable dilemma—and Homo troglodytes fit right in between.

  But if Homo troglodytes only recorded the vivid imagination of early travelers, the great apes—gibbons, chimps, orangs, and gorillas—did exist. None was adequately known or described in Western Europe before the seventeenth century, thus increasing the apparent distance between humans and the most advanced primate. Arthur O. Lovejoy, in his classic treatise, The Great Chain of Being, explicitly cited the impetus given to the study of apes as an important empirical consequence of this false theory. He wrote:

  The principle of continuity was not barren of significant consequences. It set naturalists to looking for forms which would fill up the apparently “missing links” in the chain…. The metaphysical assumption thus furnished a program for scientific research. It was therefore highly stimulating to the work of the zoologist…. It therefore became the task of science at least to increase the rapprochement of man and ape.

  The first adequate description of a great ape was not published until 1699, exactly one hundred years before the last great defense of the static chain—Charles White’s treatise, analyzed in the next essay. In that year, Edward Tyson, England’s finest comparative anatomist, published his “Orang-Outang, sive Homo sylvestris: or, the anatomy of a pygmie compared with that of a monkey, an ape, and a man.” (In Tyson’s day, orangutan, literally man of the forest, served as a general term for all great apes, both African and Asian, not only for the Asian form, as today. Tyson, overly cautious in this case, also doubted reports of Pygmy humans in Africa and assumed that
his baby chimpanzee, which he falsely regarded as nearly full grown, formed the source of such rumors.)

  The title page of Tyson’s Anatomy of a Pygmie (1699).

  Edward Tyson (1650–1708) studied at both Oxford and Cambridge, and then practiced as a physician in London. He taught human anatomy for fifteen years at Surgeon’s Hall and became chief physician to England’s most noted mental hospital, Bethlehem (whence our word bedlam). There he introduced the practice of female nursing and set up a department to follow patients after their release, an early example of outpatient care. He was, however, best known as a comparative anatomist and specialist on glandular systems. He wrote monographs on a porpoise and an opossum, but his 1699 treatise on a young chimpanzee became his most famous and enduring work. He was a wealthy, quiet, and conservative man who never married and showed unusual dedication to his anatomical studies and his avocation of classical learning. A funeral poem written to his memory in 1708 celebrated his sole devotion to Minerva, goddess of wisdom, among women:

  No Brow cou’d richer Chaplets ever twine,

  At least with Gems from Wisdom’s sacred Mine.

  No Wonder ne’er by Beauty Captive led,

  No Bridal Partner ever shared his Bed.

  No, to the blinder God no Knee e’er paid,

  To great Minerva his whole Court he made.

  Ashley Montagu’s fine biography of Tyson (see bibliography) remains the standard work on this important but neglected figure in the history of science.

  We now regard great apes as the most humanlike of primates and the closest to us in ancestry among living forms. However, great apes and humans differ substantially, not only in anatomy, but particularly in speech and mental functioning. Chimpanzees, our closest living relatives, are members of an evolutionary side branch, not ancestors or intermediate forms. But Tyson placed his pygmy, or juvenile chimpanzee, squarely in the middle between other primates and humans. When forced to categorize, Tyson did place his pygmy among the animals: “Our Pygmie has many advantages above the rest of its species, yet I still think it but a sort of ape and a mere brute; and as the proverb has it, an ape is an ape, tho’ finely clad.” Yet, in several other passages, Tyson demands an intermediate status for his chimp: “Our Pygmie is no man, nor yet the common ape; but a sort of animal between both.” (In Tyson’s day, before scientists had recognized the great apes as a separate group among primates, the term ape referred to any large monkey.)

  Tyson’s willingness to place great apes even nearer to humans than current understanding permits has become the source of a major historical misunderstanding about him—and the initial impetus for this essay based upon my continuing concern with the relationship between fact and theory. In the “heroic” school that analyzes past figures in terms of their success by modern standards, Tyson wins high acclaim for his courage in recognizing, so long ago, the affinity of apes and humans. He was able to discern this basic truth, the myth continues, for two major reasons: he was an outstanding empiricist, willing to cast aside old prejudices and simply record what he saw; and he used the modern method of comparative anatomy—explicit contrasts, part by part, of his chimp with other primates and humans.

  This tradition of praising Tyson for his supposed modernism pervades the history of comment on his great 1699 treatise. T.H. Huxley, for example, in his seminal essay on Man’s Place in Nature (1863), singled out Tyson for praise because he had written “the first account of a manlike ape which has any pretensions to a scientific accuracy and completeness.” In the preface to his biography, Ashley Montagu states that he first became interested in Tyson when he read, as a student, the comment in a standard text on anthropology (1904) that Tyson’s work “constitutes a most remarkable anticipation of modern methods of research.” George Sarton, our century’s foremost historian of science, wrote in the foreword to Ashley Montagu’s biography that Tyson’s treatise “is one of the outstanding landmarks in the history of science…a landmark in the history of the theory of evolution”—even though Tyson speaks only of the static chain, not of evolution at all.*

  The myth of Tyson’s supposed courageous modernism is belied by two anomalies, also prominently reported. First, if he was such an iconoclast in his willingness to place an animal so near our exalted selves, why is he universally described as so cautious and conservative in character? Secondly, if the award of intermediate status to his chimp was so controversial, why did it elicit so little contemporary comment—even though later generations granted Tyson so much praise? Ashley Montagu states: “The fact that Tyson is so little referred to in contemporary correspondence is not a little puzzling.”

  I believe that the solution to this dilemma lies simply in abandoning the fallacious approach to the history of science that generated it. Tyson was no modernist. He was a conservative man and he worked under the common preconceptions of his time. He did not place his chimp in an intermediate position between monkeys and humans because he anticipated evolution or simply saw more clearly through a veil of common prejudice. Rather, Tyson was a staunch exponent of the chain of being—a common and accepted ordering of nature in his time. Gaps between major groups vexed this theory sorely—and the space between monkey and man seemed particularly glaring and embarrassing. Scientists sought intermediate forms eagerly (and anxiously); Tyson’s discovery produced a welcome confirmation of an established theory—the static chain of being—not a challenge based on a radically different idea—evolution—that would not be widely and seriously discussed for another century. Tyson’s work received little comment because it was comforting and noncontroversial.

  Moreover, Tyson’s use of the comparative method does not mark him as an enlightened modernist, but also arises from his commitment to the chain of being. If you wish to place an animal between a monkey and a human, what else can you do but tabulate its relative resemblance to each?

  I do not in the least mean to criticize Tyson or to detract from his legitimate place in the pantheon of scientific heroes. Fitting a man into his time should only enhance our understanding. After reading Tyson’s treatise, I can certainly affirm the elaborate care and accuracy of his descriptions, attributes highly valued in any age. Still, as the major theme of this essay, I want to argue that the outstanding feature of Tyson’s treatise is not an accuracy emerging from the renunciation of old prejudices, but rather Tyson’s exaggeration of the humanlike character of his pygmy—a result of his prior commitment to the chain of being. Theory always influences perception, and not always for the worse.

  Tyson states right at the outset his commitment to the chain of being and his intention to use it as the organizing theme of his treatise.

  ’Tis a true remark, which we cannot make without admiration, that from minerals, to plants; from plants, to animals; and from animals, to men: the transition is so gradual, that there appears a very great similitude, as well between the meanest plant, and some minerals; as between the lowest rank of men, and the highest kind of animals. The animal of which I have given the anatomy, coming nearest to mankind, seems the nexus of the animal and rational.

  He then defends the comparative technique, not as something controversial and modern, but as the appropriate method for placing a creature in the scale of being:

  To render this disquisition more useful, I have made a comparative survey of this animal, with a monkey, an ape, and a man. By viewing the same parts of all these together, we may better observe nature’s gradation in the formation of animal bodies, and the transitions made from one to another; than which, nothing can more conduce to the attainment of the true knowledge, both of the fabrick, and uses of the parts. By following nature’s clew in this wonderful labyrinth of the creation, we may be more easily admitted into her secret recesses, which thread if we miss, we must needs err and be bewilder’d.

  Despite several assertions that, at what later centuries would call the “bottom line,” his pygmy was a “brute” and not a rational creature, Tyson continually emphasizes the humanlike
qualities of his chimpanzee. At the very end, in a list of features, he cites forty-eight points of greater resemblance between chimp and human than chimp and ape, and only thirty-four for closer affinity between chimp and ape. The entire text continually emphasizes the smoothly intermediate position of Tyson’s chimp: “In this chain of the creation, as an intermediate link between an ape and a man, I would place our pygmie.”

  Since chimps are, in general anatomical aspect, probably more similar to other primates than to humans, this conclusion requires some exaggeration of the humanlike qualities of Tyson’s pygmy. Quite unconsciously, I suspect, and for two quite different reasons, Tyson continually overemphasizes the human similarities and as often underestimates the relationship with apes.

  For the first reason, Tyson simply and consistently favors the human side in ambiguous situations. Note particularly his statements on posture. Tyson’s chimp was brought to England from Angola and arrived both ill and very weak (it died within a few months and thus became available for Tyson’s dissection). He observed that it occasionally but rarely walked erect; Tyson’s chimp usually progressed, as great apes characteristically do, by walking on its knuckles—feet firmly on the ground but hands bent over. Tyson attributed this peculiar posture to its weakened state and insisted that its natural mode of locomotion must be erect on legs alone, as in humans—even though his empirical data identified knuckle walking as far more common: