To compare humans with other animals in regard to behavior amenable to observation is just; but unfavorable comparisons on the basis of first-person accounts emanating from within the animals themselves, their reports of their thoughts and insights, are unfair if no channel of communication into their internal lives has yet been opened. Absence of evidence is not evidence of absence. Were we better able to enter into the mind of the ape, might we not find much more there than we guess?—a point made almost three centuries ago by Henry St. John, the first Viscount Bolingbroke:Man is connected by his nature … with the whole tribe of animals, and so closely with some of them, that the distance between his intellectual faculties and their … appears, in many instances, small, and would probably appear still less, if we had the means of knowing their motives, as we have of observing their actions.3
An oft-cited difference purported to exist between human beings and other animals is religion. Only humans, it is said, have religion, and that settles the matter. But what is religion? How could we know whether animals have it? In The Descent of Man, Darwin cites the comment, “a dog looks on his master as a god.” Ambrose Bierce4 defined reverence as “the spiritual attitude of a man to a god and a dog to a man.” The omega looks on the alpha as something like a god, and the depths of his submission and self-abasement are reached in few extant religions. It is hard to know how profoundly dogs or apes feel reverence, how tinged with awe their attitudes are toward a stern “master” or a well-established alpha, whether they have a sense of the sacred, pray for forgiveness, and otherwise seek to placate and influence forces more powerful than they. Animals raised, educated, and disciplined by much stronger and wiser parents, animals spring-loaded to fit into a dominance hierarchy, animals moreover faced with the daunting presence of human beings armed with life-and-death powers and meting out rewards and punishment—such animals may well have feelings akin to what we call religious. Many mammals and all primates satisfy these conditions.
Over the course of human history, some religions, it is true, have become much more than this—at their best transcending intimidation, hierarchy, and bureaucracy, while providing comfort for the powerless. A few, rare, religious teachers have acted as a conscience for our species, have inspired millions by the example of their lives, have helped us to break out of baboonish lockstep. But none of this contradicts the thesis that a generalized religious predisposition, ready to be put to use by the local social structure, may be a commonplace in the kingdom of the animals.
Perhaps, if we were able to peer into the mind of the ape in a state of nature, we would find—among a flurry of other feelings—a sense of satisfaction about its apeness rivaling ours about our humanity. Every species may feel something similar. It would be far more adaptive than its opposite. If anything like this is true, then we would be denied even our self-congratulatory distinction of being the only animal that makes self-congratulatory distinctions.
If we have not much peered into the hearts and minds of other species and have not even studied them carefully, we may impute to them virtues and strengths as well as vices and deficiencies that in fact they lack. Consider this bit of verse by the poet Walt Whitman:I think I could turn and live with animals, they’re so placid and self-contain’d,I stand and look at them long and long.
They do not sweat and whine about their condition,They do not lie awake in the dark and weep for their sins,They do not make me sick discussing their duty to God,Not one is dissatisfied, not one is demented with the mania of owning things,Not one kneels to another, nor to his kind that lived thousands of years ago,Not one is respectable or unhappy over the whole earth
On the basis of the evidence presented in this book, we doubt if any of Whitman’s six purported differences between other animals and humans is true—at least given a little poetic license; that is, in the spirit if not the letter of the poem. Montaigne thought6 that when we conclude that other animals have “ambition, jealousy, envy, revenge, superstition, and despair,” we are simply projecting our own “sickly qualities” onto the beasts; but this goes too far, as the lives of the chimps make clear. While many commentators have exaggerated the differences between humans and “animals” and warned of anthropomorphizing, others, like Whitman and Montaigne, have romanticized and sentimentalized the animals. Both excesses serve to deny our kinship.
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The proximate cause of human success must have something to do with the conjoining of our intelligence and our talent for making and using tools. Surely, our globe-girdling civilization arises chiefly from these two abilities. Without them, we would be nearly defenseless. But “a little dose … of judgment or reason often comes into play, even in animals very low in the scale of nature,” Darwin wrote in The Origin. Late in life, he made extensive studies of what you might think is an unpromising subject, the intelligence of earthworms. He gave them intelligence tests involving the manipulation of real and artificial leaves. They did very well. Flatworms can work their way through a simple maze to get a reward; even worms have a degree of intelligence. Galapagos woodpecker finches, studied by Darwin on the voyage of the Beagle, use twigs to worry wood-dwelling larvae out of branches; even birds have a rudimentary technology.
Certainly we could not have invented civilization without intelligence and technology. But it would be unfair to describe civilization as the determining characteristic of our species, or as establishing the level of intelligence and manual dexterity required for our definition, especially because the first 99 percent of the tenure of humans on Earth was spent in an uncivilized state. We were humans then, as now, but we hadn’t dreamed up civilization. Yet the fossil remains of the earliest known humans and hominids—dating back not just hundreds of thousands but millions of years—are often accompanied by stone tools. We had the talents, at least in partial measure. We just hadn’t gotten around to civilization yet.
The contrast between the proclivity for tools in humans and the absence of tool use in so many other animals has made it tempting to define ourselves as the tool-using or the tool-making animal—as seems to have first been suggested by one of the members of Josiah Wedgwood’s and Erasmus Darwin’s Lunar Society, Benjamin Franklin. On April 7, 1778, James Boswell confesses to admiring Franklin’s definition. The ever-grumpy and sometimes over-literal Samuel Johnson objects: “But many a man never made a tool; and suppose a man without arms, he could not make a tool.” Again, if we are to define a human being, should we use traits that, without exception, every human being possesses, or traits that may be present only potentially? And if the latter, who knows what traits lie smoldering in other animals, not yet fully elicited by circumstance or necessity?
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Blasé, matter-of-fact, encumbered by the infant (who, face to her chest, clutches her fur), she carefully positions the hard-shelled fruit on the log and smashes it open—using a stone tool procured for the purpose. Hammer and anvil. No light bulb goes off above her head. There’s no chin to fist, no hint of insight struggling to emerge, no moment of revelation, no strains from Also Sprach Zarathustra. It’s just another routine, humdrum thing that chimps do. Only humans, who know where tools can lead, find it remarkable.