Shadows of Forgotten Ancestors

by Carl Sagan

  Savage-Rumbaugh and her co-workers toy with the possibility that chimps and bonobos exhibit impressive facilities to learn something of human languages because they have their own languages, vocal or gestural, that we have not yet deciphered.33 In announcing the location of prey, or predators, or a hostile patrol, rudimentary language would be strongly favored by natural selection. Long before humans and chimps went their separate ways, considerable aptitudes for thought, invention, and language were probably percolating in our primate ancestors.

  But partly because of Terrace’s work, and partly because of the perceived difficulty of doing clean, controlled, non-anecdotal experiments on so emotional a being as a chimpanzee, financial support for many of these studies has nearly disappeared. In one case, the colony where apes had been taught Ameslan had fallen on hard times. Years had passed. Support was drying up. No one seemed interested in conversing with the chimps anymore. The grounds had become weedy and overgrown. The inmates were about to be shipped to laboratories for medical experimentation. Before the end, they were visited by two people who had known them in the old days. “What do you want?” the visitors asked in Ameslan. “Key,” two chimps are said to have signed back from behind bars, one after the other. “Key.” They wanted out. They wanted to escape. Their request was not granted.34

  ——

  When chimps approach sexual maturity, their behavior changes. Both sexes are then much stronger than humans and given to occasional, unpredictable bouts of rambunctiousness and violence. So as the chimps get older, almost inevitably the experimenters find themselves driven to use steel cages, collars, leashes, and electric cattle prods. The chimps must feel, bit by bit, betrayed by the humans and less inclined to cooperate in their strange language games. Accordingly, back in the days when the research was generously supported, it was thought prudent to terminate experiments on teaching chimps language—requiring, as it does, close face-to-face daily contact—when they begin to mature. As a result, we do not know what the linguistic abilities of an adult chimpanzee might be. Lucy, like some aging child actor, was forced into retirement just a little after puberty. The laboratory in which she had demonstrated her accomplishments in sign language was closed.

  Jane Goodall, who had by then spent a decade and a half living with chimps in the wild, was astonished on meeting Lucy:

  Lucy, having grown up as a human child, was like a changeling, her essential chimpanzeeness overlaid by the various human behaviours she had acquired over the years. No longer purely chimp yet eons away from humanity, she was man-made, some other kind of being. I watched, amazed, as she opened the refrigerator and various cupboards, found bottles and a glass, then poured herself a gin and tonic. She took the drink to the TV, turned the set on, flipped from one channel to another then, as though in disgust, turned it off again. She selected a glossy magazine from the table and, still carrying her drink, settled in a comfortable chair. Occasionally, as she leafed through the magazine she identified [in Ameslan] something she saw …35

  In the second half of her life, Lucy lived with other chimpanzees on a small island in Gambia. Her adjustment to Africa was slow and difficult, and she became

  an emaciated, hairless wreck … She had been born and raised in the United States, and in pampered upper-middle-class circumstances … Lucy, the fastidious, toilet-trained chimpanzee princess … slept on a mattress, sipped soda, developed schoolgirl crushes, and would sit in the living room during the afternoon and leaf through magazines.36

  But after a year or two in Gambia, thanks to the loving care of Janis Carter, she began to adjust. She had regular contact with humans and was often the first chimp to greet visitors to the island. She was used to humans. Her relations with other chimps were more strained. She had missed out on the rollicking childhood of a chimp in the wild.

  In 1987 Lucy’s skeleton was discovered. The most likely reconstruction of events is that humans came to the island, killed Lucy, probably by shooting her, and skinned her body. Her hands and feet, the very organs that had made her famous, were missing.37 Those responsible have never been found.38

  ON IMPERMANENCE

  In the life of a man, his time is but a moment, his being an incessant flux, his senses a dim rushlight, his body a prey of worms, his soul an unquiet eddy, his fortune dark, and his fame doubtful. In short, all that is of the body is as coursing waters, all that is of the soul as dreams and vapours; life a warfare, a brief sojourning in an alien land; and after repute, oblivion. Where, then, can man find the power to guide and guard his steps? In one thing and one alone: the love of knowledge.

  MARCUS AURELIUS, Meditations39

  * Ring-tailed lemur males will smear a pheromone they generate onto their tails and then wave these prominent, black-and-white-banded appendages at each other, wafting the smell into the air. This is mainly a competition for females: Apparently the most aromatic lemur tends to win the most attractive female. In one lemur species, all adult males may have their tail waves answered in the same evening, because all adult females come into heat together, by the light of the silvery (and full) moon.

  * Used in panning for gold.

  * Also called the fallacy of the enumeration of favorable circumstances. No dishonest intent is implied; it is merely one of those failures of logic that humans are prey to. We tend not to be dispassionate observers.

  * One expert reviewer likens this sentence to saying that “90% of the materials dug from a gold mine are not gold ore”

  Chapter 19

  WHAT IS HUMAN?

  Having proved mens & brutes bodies on one

  type: almost superfluous to consider minds.

  CHARLES DARWIN

  Notebooks on Transmutation of Species1

  We humans are the dominant species on the planet, a status affirmed by several standards—our ubiquity, our subjugation (politely called domestication) of many animals, our expropriation of much of the primary photosynthetic productivity of the planet, our alteration of the environment at the Earth’s surface. Why us? Of all the promising lifeforms—implacable killers, professional escape artists, prolific replicators, nearly invisible beings that no macroscopic predator can find—why did one primate species, naked, puny, and vulnerable, manage to subordinate all the rest and to make this world, and others, its domain?

  Why are we so different? Or are we? Unambiguous definitions of humans—definitions that include almost all members of our species, but no one else—can be produced from anatomy or from DNA base sequencing. But they fail the purpose. They explain nothing that we recognize as fundamental about ourselves. Perhaps sometime in the future we will discover that unique sequences of As, Cs, Gs, and Ts encode for particular sequences of amino acids that constitute particular proteins that catalyze particular chemical reactions that motivate particular behavior that we might agree is characteristically human. But so far no such sequence has been found.

  If, then, we can discern no clear-cut distinction in our chemistry (or anatomy) that explains our dominant role, the only ready alternative is to survey our behavior. It seems plausible that the sum of our everyday activities would be sufficiently defining, but a surprisingly large number of those activities can be performed by apes. For example, here’s a description of the accomplishments of Consul, the first chimp acquired, in 1893, by the zoo in Manchester, England:

  [He was] able to put on his own coat and hat, seat himself in his own carriage for a drive, sit at table with company, use his knife and fork with propriety, pass his plate for a fresh supply of food, use his serviette [napkin], wash his hands after meals, put coals on the fire, ring the bell for the maid, go into the kitchen for a romp with the girls, walk into his hotel, shake hands with his friends, kiss the barmaid, smoke his pipe, and mix his own drinks.2

  True, Consul’s deportment may be dismissed as mere mimicry; but that may also be said of those of us who marvel at his abilities.

  Is there anything we do that’s uniquely human—that all or almost all of us, of eve
ry culture, throughout history, do and that no other animal does? You might think something along these lines would be easy to find, but the subject is redolent with self-deception. We have too much of a stake in the answer to be unbiased.

  Philosophers of marauding high-technology civilizations have often argued that humans deserve a category distinct from and above all the other animals.* It is not enough that humans have a different assortment of the qualities evident in the other animals—more of some traits, fewer of others. A radical difference in kind, not some fuzzy-edged difference in degree, is needed, longed for, sought.

  Most of the philosophers adjudged great in the history of Western thought held that humans are fundamentally different from the other animals. Plato, Aristotle, Marcus Aurelius, Epictetus, Augustine, Aquinas, Descartes, Spinoza, Pascal, Locke, Leibniz, Rousseau, Kant, and Hegel were all proponents “of the view that man differs radically in kind from [all] other things”; except for Rousseau, they all held the essential human distinction to be our “reason, intellect, thought, or understanding.”3 Almost all of them believed that our distinction arises from something made neither of matter nor of energy that resides within the bodies of humans, but of no one else on Earth. No scientific evidence for such a “something” has ever been produced. Only a few of the great Western philosophers—David Hume, for instance—argued, as Darwin did, that the differences between our species and others were only of degree.

  Many famous scientists, while fully accepting evolution, have parted company with Darwin on this question. For example, Theodosius Dobzhansky: “Homo sapiens is not only the sole tool-making and the sole political animal, he is also the sole ethical animal.”4 Or George Gaylord Simpson: “[M]an is an entirely new kind of animal … [T]he essence of his unique nature lies precisely in those characteristics that are not shared with any other animal,”5 especially self-awareness, culture, speech, and morality. The difference between humans and non-human animals according to a number of contemporary philosophers6 goes like this:

  Precisely because they are incapable of conceptual thought, animals … are not only (1) incapable of sentence-making that includes statements about the past and future, (2) unable to fabricate tools for remote future use, (3) devoid of a cumulative cultural inheritance that constitutes a long historical tradition, but they are also (4) incapable of any behavior that is not rooted in the perceptually apprehended present situation.

  Apart from quibbles about how long is long in (3), every one of these confident assertions now appears false, on the basis of the sort of evidence we have presented or are about to present in this book. Even if we ourselves are not personally scandalized by the notion of other animals as close relatives, even if our age has accommodated to the idea, the passionate resistance of so many of us, in so many epochs and cultures, and by so many distinguished scholars, must say something important about us. What can we learn about ourselves from an apparent error so widespread, propagated by so many leading philosophers and scientists, both ancient and modern, and with such assurance and self-satisfaction?

  One of several possible answers: A sharp distinction between humans and “animals” is essential if we are to bend them to our will, make them work for us, wear them, eat them—without any disquieting tinges of guilt or regret. With untroubled consciences, we can render whole species extinct—for our perceived short-term benefit, or even through simple carelessness. Their loss is of little import: Those beings, we tell ourselves, are not like us. An unbridgeable gap has thus a practical role to play beyond the mere stroking of human egos.7 Darwin’s formulation of this answer was: “Animals whom we have made our slaves, we do not like to consider our equals.”8

  ——

  We now proceed, in Darwin’s footsteps,9 to examine some of the multitude of proffered definitions of ourselves, explanations of who we are. We will try to see whether they make sense, especially in the light of what we know about the other beings that share the Earth with us.

  One of the earliest attempts at an unambiguous characterization of humanity was Plato’s: Man is a featherless biped. When news of this advance in the art of definition reached the philosopher Diogenes, so the story goes, he introduced a plucked chicken into the weighty deliberations of Plato’s celebrated Academy, asking the assembled scholars to salute “Plato’s man.” This is of course unfair, because chickens are ordinarily born with feathers, just as they are ordinarily born with two feet. How we mutilate them afterwards does not change their fundamental nature. But the academicians took Diogenes’ challenge seriously and added another qualification: Humans were redefined as featherless bipeds with broad flat nails.

  Surely this does not get us very far to the essence of human nature. The Platonic definition might suggest, though, a necessary if not a sufficient condition, because standing on two legs is essential for freeing the hands, hands are the key to technology, and many people think our technology defines us. Still, raccoons and prairie dogs have hands and no technology, and bonobos walk upright a good part of their lives. We will address chimpanzee technology shortly.

  ——

  In his classic justification of free enterprise capitalism, Adam Smith asserts that “the propensity to truck, barter, and exchange one thing for another … is common to all men, and to be found in no other race of animals.”10 Is this true? Private property was proposed as the central difference between humans and the other animals by Martin Luther in the sixteenth century, and by Pope Leo XIII in the nineteenth.11 Is this true?

  Chimpanzees are fond of trade, and understand the idea very well: food for sex, a back rub for sex, betrayal of the leader for sex, spare my baby’s life for sex, virtually anything for sex. Bonobos take these exchanges to a new level. But their interest in barter is by no means restricted to sex:

  [Chimpanzees] are famous for their tradesmanship. Experimental studies indicate that the ability comes without any specific training. Every zookeeper who happens to leave his broom in the baboon cage knows there is no way he can get it back without entering the cage. With chimpanzees it is simpler. Show them an apple, point or nod at the broom, and they understand the deal, handing the object back through the bars.12

  With regard to females at least, chimp males have a well-developed sense of private property (raised to institutional status among the hamadryas baboons), and a rudimentary sense of private property attaches to food and to some tools.

  The Wealth of Nations was published in 1776, well before any serious study had been made of the lives of the apes, even in captivity. However, Smith’s argument about the uniqueness of trade among humans is embedded in a deeper misreading of the animal world:

  In almost every other race of animals, each individual, when it is grown up to maturity, is entirely independent and in its natural state has occasion for the assistance of no other living creature. But man has almost constant occasion for the help of his brethren, and it is in vain for him to expect it from their benevolence only. He will be more likely to prevail if he can interest their self-love in his favor and show them that it is for their own advantage to do for him what he requires of them.13

  But the gregariousness of the primates is one of their hallmarks. Mutual aid in working both sides of the predator/prey relationship and in conflict with other groups of the same species is widespread, not just among the primates, but among most mammals and birds.

  While selfishness, exploitation, and trade are commonplace in chimpanzee society, we cannot use this fact along with our kinship with chimps to justify laissez faire economics. Nor can we use it to discredit free market societies on the grounds of their being ape-like.* Cooperation, friendship, and altruism are also chimp traits, but this is not an argument for some competing socialist economic doctrine. Recall the macaques who would rather go hungry than administer an electric shock to other, not closely related macaques—going so far as to reject even substantial material incentives. Is this a rebuke to advocates of capitalism? At least as far back as Aesop, animal behavior
has been used to buttress this or that economic theory. Even in our ideological debates, we make the other animals work for us.

  ——

  “Man is a social animal,” wrote Aristotle, or, as it is sometimes translated, “Man is a political animal.” This was meant to be characteristic of humans, but not defining; again, a necessary but not a sufficient condition. The subtle and volatile factionalism of chimp and bonobo societies shows how far off the mark this is as a distinction of humanity. The social insects—ants, bees, termites—have much better organized and much more stable social structures than humans. Particular aspects of human social behavior fare no better, although a great many such definitions have been proposed: For example, humans tenderly cherish their young, but so do most other mammals and birds.

  “Courage is the peculiar excellence of man,” Tacitus recorded the Roman aristocrat Claudius Civilis as saying.14 Even if the heroic exploits of mother birds shamming a broken wing, or of elephants and chimps saving their young from predators or rushing water, or of the beta hind staring the wolf in the eye so her companions can escape—even if such examples were unknown in the time of this Claudius, didn’t he know about dogs? He was put in chains and brought before Nero. History does not record how much of the “peculiar excellence” was available to him in his hour of need.