The Flamingo’s Smile

by Stephen Jay Gould

  When it went as a quadruped on all four, ’twas ackwardly; not placing the palm of the hand flat to the ground, but it walk’d upon it’s knuckles, as I observed it to do, when weak, and had not strength enough to support it’s body…. Walking on it’s knuckles, as our pygmie did, seems no natural posture; and ’tis sufficiently provided in all respects to walk erect.

  We can’t blame Tyson for not knowing that great apes normally walk on their knuckles, for this most uncharacteristic pose for animals was not well described in his time. Still Tyson’s defense of upright (or humanlike) posture as the normal mode for chimps does seem a bit forced, conditioned more by preconceptions about intermediate status on the chain of being than by direct attention to raw data. Thus, in writing “we may safely conclude, that nature intended it a biped,” Tyson discusses the articulation of femur to pelvis and the “largeness of the heelbone in the foot, which being so much extended, sufficiently secures the body from falling backwards.” Yet in the same discussion he conveniently omits other anatomical features described earlier that might lead us to doubt upright posture—particularly the major differences in pelvic structure between chimps and humans, and the handlike foot with its short and weak big toe.

  Since primates are visual animals, we must never omit (though historians often do) the role played by scientific illustrations in the formation of concepts and support of arguments. Tyson’s magnificent plates are all constructed to enhance the argument for upright posture, even in the absence of direct evidence for it (I include four reproductions with this essay). The first shows his pygmy from the front, standing fully erect, although note that Tyson cleverly provides it with a walking stick to indicate the difficulty that he couldn’t help observing in this mode of progress! Tyson writes: “Being weak, the better to support him, I have given him a stick in his right-hand.” The second plate depicts the chimp from the back, upright again, but this time holding on to a rope above its head for support! Finally, the plates of musculature and skeletal system are all portrayed in a fully upright human posture.

  Front view of Tyson’s pygmie from his 1699 treatise. Note how he reconstructed the animal as walking erect to enhance its humanlike features. But it did not walk this way in life, so Tyson supplied a walking stick. FROM TYSON, 1699.

  Back view of Tyson’s chimp, this time holding on to a rope for support. FROM TYSON, 1699.

  In many other passages, Tyson awards almost human attributes and emotions to his pygmy. He recalls with delight, for example, how the chimp loved to wear clothes and put them on while in bed, although he noted that it never learned not to perform nature’s functions in the same place as well:

  After our pygmie was taken, and a little used to wear cloaths, it was fond enough of them; and what it could not put on himself, it would bring in his hands to some of the company to help him to put on. It would lie in a bed, place his head on the pillow, and pull the cloaths over him, as a man would do; but was so careless, and so very a brute, as to do all nature’s occasions there.

  Often, Tyson discussed the chimp’s behavior in purely human terms: “For I heard it cry myself like a child; and he hath been often seen to kick with his feet, as children do, when either he was pleased or angered.” In one passage, he even grants superiority to his chimp in matters of temperance:

  Once it was made drunk with punch, (and they are fond enough of strong liquors) but it was observed, that after that time, it would never drink above one cup, and refused the offer of more than what he found agreed with him. Thus we see instinct of nature teaches brutes temperance; and intemperance is a crime not only against the laws of morality, but of nature too.

  As a second reason for exaggerating similarities between his chimp and humans, Tyson made a crucial error. He knew that his pygmy was a young animal, for extremities of the long bones were still formed in cartilage and not fully ossified, but he regarded it as nearly full grown because he mistook the complete set of milk teeth for a permanent dentition (the baby teeth of great apes do, in some respects, resemble the permanent teeth of humans). Thus, he did not realize how young an animal—a baby almost—he was dissecting. (This misidentification also enhanced his subsequent error, in a philological treatise appended to his anatomy, of attributing classical legends and more modern reports of African Pygmies to the same animal, which he regarded as just over two feet tall when fully grown.)

  I have often discussed in these essays the role of neoteny (literally, holding on to youth) in human evolution (see Ever Since Darwin and The Panda’s Thumb). We have evolved by slowing down the general developmental rates of primates and other mammals. Thus, human adults resemble juvenile chimps and gorillas much more closely than adult great apes. Consequently, the skeleton of a baby chimpanzee will retain many humanlike characters that an adult would lose—including a relatively large head (human babies, of course, also have relatively larger heads than human adults), a more upright mounting of the head on the spine (since the foramen magnum, or hole of articulation between skull and spinal column, moves back with growth), a more bulbous cranium (since the brain grows much more slowly than the body after birth), weaker brow ridges, and smaller jaws. Tyson’s plate of his pygmy’s skeleton, a remarkably accurate figure (I have seen photos of the original bones), shows all these humanlike features.

  Tyson also noted all these features with delight in his text, but missed the coordinating theme—not that chimps are so like humans, but that he had dissected a very young animal and juvenile primates resemble adult humans in many ways, without demonstrating direct descent or relationship. He wrote, for example:

  As for the face of our pygmie, it was liker a man’s than ape’s and monkeys faces are: for it’s forehead was larger, and more globous, and the upper and lower jaw not so long or prominent, and more spread; and it’s head more than as big again as either of theirs.

  The skeleton of Tyson’s chimp, again with human-like features exaggerated in position of skull on spinal column, upright posture, and subtle details of proportions. A classic example of the use of illustration to demonstrate a point (or illustrate a bias). FROM TYSON, 1699.

  The musculature of Tyson’s chimp. The bizarre “peeling back” of exterior muscles (to show others within) was a convention of anatomical illustration at the time. FROM TYSON, 1699.

  Indeed, the large and humanlike brain of Tyson’s chimp posed quite a problem. Tyson had already determined that the vocal apparatus of his pygmy was sufficiently similar to our own for speech, so why did it not talk? Perhaps a deficiency of brain prevented the expression of this most human attribute. Yet Tyson found little difference, either in basic structure or relative size, between his pygmy’s brain and our own.

  One would be apt to think, that since there is so great a disparity between the soul of a man, and a brute, the organ likewise in which ’tis placed should be very different too. Yet by comparing the brain of our pygmie with that of a man, and with the greatest exactness, observing each part in both; it was very surprising to me to find so great a resemblance of the one to the other, that nothing could be more.

  In a fascinating passage, displaying the seventeenth-century context of his work, Tyson simply denied that physical structure must provide a key to function. The brains are similar indeed, but humans possess some higher principle that potentiates the same matter in a different way:

  There is no reason to think, that agents do perform such and such actions, because they are found with organs proper thereunto; for then our pygmie might be really a man. The organs in animal bodies are only a regular compages of pipes and vessels, for the fluids to pass through, and are passive. What actuates them, are the humours and fluids: and animal life consists in their due and regular motion in this organical body. But those nobler faculties in the mind of man, must certainly have a higher principle; and matter organized could never produce them; for why else, where the organ is the same, should not the actions be the same too?

  If the chain of being had enduring value as a
heuristic prod for the exploration of missing links, and if gaps grew greater as the chain advanced, then what about the chasm even more glaring than the one that Tyson thought he had filled between ape and human—between humans and angels or other celestial beings? Tyson gave the problem a cursory comment, more political than scientific, by suggesting in his dedicatory epistle to John Sommers, Lord High Chancellor of England and President of the Royal Society (publishers of his treatise), that men of such ample learning might well plug the gap themselves!

  The animal of which I have given the anatomy, coming nearest to mankind; seems the nexus of the animal and rational, as your Lordship, and those of your High Rank and Order for knowledge and wisdom, approaching nearest to that kind of beings which is next above us; connect the visible, and invisible world.

  Yet, though Tyson didn’t pursue this issue, the chain’s gap between human and angel became a major impetus for early speculations about a subject currently popular and, for the first time, perhaps approachable—exobiology (see essays in part 7). For the obvious solution must contend that creatures more advanced than humans, and plugging the gap between man and angel, inhabit other planets. The philosopher Immanuel Kant, for example, argued that a large and heavy planet like Jupiter must support such higher creatures. And Alexander Pope gave them explicit notice in his couplets on the chain of being from his Essay on Man (while praising Isaac Newton as a paragon of earthly wisdom at the same time):

  Superior beings, when of late they saw,

  A mortal man unfold all nature’s law,

  Admired such wisdom in an earthly shape

  And show’d a Newton as we show an ape.

  Pope only indulged in reveries framed in heroic couplets. Tyson was the man who first showed an ape with accuracy and admirable thoroughness.

  18 | Bound by the Great Chain

  IN A Child’s Garden of Verses, Robert Louis Stevenson labeled the following couplet as a Happy Thought:

  The world is so full of a number of things,

  I’m sure we should all be as happy as kings.

  Yet most of us do not rejoice when we contemplate the overwhelming diversity of nature; we are stunned by complexity and confusion. We cannot be satisfied until we have established some kind of order; we must make sense of the bewildering variety by classifying it.

  Evolution is a satisfying ordering principle and we use it without hesitation today, for evolution both records the pathway of nature and allows us to classify organisms in a coherent manner. But what systems did scientists use before evolution became so popular during the nineteenth century? The “great chain of being,” or even gradation of all living things, surely held pride of place among all competitors. Arthur Lovejoy, the celebrated historian of ideas who traced the lineage of this notion in his greatest work (see bibliography), called the chain of being “one of the half-dozen most potent and persistent presuppositions in Western thought. It was, in fact, until not much more than a century ago probably the most widely familiar conception of the general scheme of things, of the constitutive pattern of the universe.”

  In the great chain of being, each organism forms a definite link in a single sequence leading from the lowest amoeba in a drop of water to ever more complex beings, culminating in, you guessed it, our own exalted selves.

  Mark how it mounts to man’s imperial race,

  from the green myriads in the peopled grass.

  wrote Alexander Pope in his expostulations in heroic couplets from the Essay on Man.

  Since we tend to confuse evolution with progress, the chain of being has often been misinterpreted as a primitive version of evolutionary theory. Although some nineteenth-century thinkers, in Lovejoy’s words, “temporalized” the chain and converted it into a ladder that organisms might climb in their evolutionary advance, the original chain of being was explicitly and vehemently antievolutionary. The chain is a static ordering of unchanging, created entities—a set of creatures placed by God in fixed positions of an ascending hierarchy representing neither time nor history, but the eternal order of things. The static nature of the chain defines its ideological function: Each creature must be satisfied with its assigned place—the serf in his hovel as well as the lord in his castle—for any attempt to rise will disrupt the universe’s established order. Again, Alexander Pope:

  From Nature’s chain whatever link you strike,

  Tenth, or ten thousandth, breaks the chain alike.

  In this essay I shall analyze the arguments presented in England’s last influential defense of the chain as a static order—physician and biologist Charles White’s 1799 treatise, “An account of the regular gradation in man, and in different animals and vegetables.” Charles White (1728–1813), who lived and practiced in Manchester, England, was a surgeon renowned for his work in obstetrics, particularly for his insistence on absolute cleanliness during delivery. In 1795, he presented his thoughts on the chain of being to the Literary and Philosophical Society of Manchester. He published the results four years later.

  For this conservative physician, the chain functioned in its usual way as an ideological support for social stability and traditional values. From the static nature of the chain itself, White inferred the necessary existence of God as a creative agent—for the only alternative would convert the chain into a temporal product of evolution, a clearly unacceptable interpretation. In the last line of his treatise, White justifies his labors by writing that “whatever tends to display the wisdom, order, and harmony of the creation, and to evince the necessity of recurring to a Deity as a first cause, must be agreeable to man.” And although White expressed his opposition to slavery, and insisted that he merely wished to examine a proposition in natural history, not to cast aspersions upon any race, his conventional ranking of human groups with European whites on top and African blacks on the bottom certainly reinforced the prejudices of his comfortable Caucasian contemporaries. White insisted, speaking of himself:

  Neither is he desirous of assigning to any one a superiority over another, except that which naturally arises from superior bodily strength, mental powers, and industry, or from the consequences attendant upon living in a state of society. He only wishes to investigate the truth, and to discover what are the established laws of nature respecting his subject; apprehending, that whatever tends to elucidate the natural history of mankind, must be interesting to man.

  The chain of being had always vexed biologists because, in some objective sense, it doesn’t seem to describe nature very well. How can we arrange all organisms in a single, finely gradated chain when enormous gaps seem to pervade nature’s system—what comes between plants and animals or invertebrates and vertebrates, for example? And how can we place into a hierarchy of perfection those creatures that seem to represent equivalent variations of a basic design, not lower or higher productions—the breeds of dogs, for example, or the persistent dilemma of human racial diversity?

  In an important way the chain of being had always been a bad argument, even in its own terms and for its own time—at least if one believes that a theory about nature should record its literal appearance accurately (a criterion not always in vogue among the learned). Paradoxically, this very feature of poor harmony with nature makes the chain of being a particularly interesting subject for analysis. Good arguments don’t provide nearly as much insight into human thought, for we can simply say that we have seen nature aright and have properly pursued the humble task of mapping things accurately and objectively. But bad arguments must be defended in the face of nature’s opposition, a task that takes some doing. The analysis of this “doing” often provides us with insight into the ideology or thought processes of an age, if not into the modes of human reasoning itself. White’s defense of the static chain is particularly forthright and unsubtle, but no different in substance from other, more sophisticated versions. It thus becomes an excellent primer for the construction of dubious arguments.

  White regarded the various human races as separately created
species (consistent with his antievolutionary view of gradation in the chain of being) and devoted his treatise to ordering these races as a single sequence from lower to higher. His book pursues two difficult arguments (in sequence) to reach its dubious conclusion. First, White must justify the chain of being in general, and amidst the large gaps that seem to separate plants from animals, and apes from humans. Second, he must arrange human races in a single chain, even though their variation is so multifarious that diverse criteria seem to yield different orderings. In short, how do you construct a single chain when nature seems to present abundant variation but little hierarchy?

  The first part of White’s treatise attempts to justify the chain as a general ordering principle for all of life. He first tackles the problem of apparent gaps between major kingdoms, plants and animals in particular. Previous advocates of the chain had generally “resolved” this dilemma by proposing fanciful arguments for intermediate forms. Thus, Charles Bonnet advocated asbestos as transitional between minerals and plants because its fibrous nature recalled the vascular systems of plants. And the freshwater hydra, a relative of corals, was widely heralded, after its discovery in 1739, as an intermediate form between plants and animals because (like plants) it seemed to lack complex internal organs and it propagated asexually by budding.

  White paid traditional homage to hydras, but his main strategy for bridging the gap between plants and animals invoked an argument for similarity of anatomical design—for if he could show that plants and animals did not differ in basic design, but proceeded from the same mold with plants as less complex versions of the same fundamental plan, then a single order could be constructed. White proposed three poor arguments in attempting to establish a unity of structure between plants and animals. First, he invoked some bad analogies in claiming, for example, that since plants drop their leaves and mammals shed their hair, a fundamental similarity unites bushes and baboons. Second, he plied simple misinformation in claiming that plants have lungs for breathing. Third, he cited similarities now judged irrelevant because they are too general to support any claim for structural similarity—for example, that plants, as well as animals, are subject to disease.