One of Us

Can animals think or feel, experience joy or sadness? Can they know their own existence?

By John Jeremiah Sullivan


Young Herdsmen with Cows, by Aelbert Cuyp, ca. 1655–60. The Metropolitan Museum of Art, Bequest of Benjamin Altman, 1913.

These are stimulating times for anyone interested in questions of animal consciousness. On what seems like a monthly basis, scientific teams announce the results of new experiments, adding to a preponderance of evidence that we’ve been underestimating animal minds, even those of us who have rated them fairly highly. New animal behaviors and capacities are observed in the wild, often involving tool use—or at least object manipulation—the very kinds of activity that led the distinguished zoologist Donald R. Griffin to found the field of cognitive ethology (animal thinking) in 1978: octopuses piling stones in front of their hidey-holes, to name one recent example; or dolphins fitting marine sponges to their beaks in order to dig for food on the seabed; or wasps using small stones to smooth the sand around their egg chambers, concealing them from predators. At the same time neurobiologists have been finding that the physical structures in our own brains most commonly held responsible for consciousness are not as rare in the animal kingdom as had been assumed. Indeed they are common. All of this work and discovery appeared to reach a kind of crescendo last summer, when an international group of prominent neuroscientists meeting at the University of Cambridge issued “The Cambridge Declaration on Consciousness in Non-Human Animals,” a document stating that “humans are not unique in possessing the neurological substrates that generate consciousness.” It goes further to conclude that numerous documented animal behaviors must be considered “consistent with experienced feeling states.”

That is technical language, but it speaks to a riddle age-old and instinctive. These thoughts begin, for most of us, typically, in childhood, when we are making eye contact with a pet or wild animal. I go back to our first family dog, a preternaturally intelligent-seeming Labrador mix, the kind of dog who herds playing children away from the street at birthday parties, an animal who could sense if you were down and would nuzzle against you for hours, as if actually sharing your pain. I can still hear people, guests and relatives, talking about how smart she was. “Smarter than some people I know!” But when you looked into her eyes—mahogany discs set back in the grizzled black of her face—what was there? I remember the question forming in my mind: can she think? The way my own brain felt to me, the sensation of existing inside a consciousness, was it like that in there?

For most of the history of our species, we seem to have assumed it was. Trying to recapture the thought life of prehistoric peoples is a game wise heads tend to leave alone, but if there’s a consistent motif in the artwork made between four thousand and forty thousand years ago, it’s animal-human hybrids, drawings and carvings and statuettes showing part man or woman and part something else—lion or bird or bear. Animals knew things, possessed their forms of wisdom. They were beings in a world of countless beings. Taking their lives was a meaningful act, to be prayed for beforehand and atoned for afterward, suggesting that beasts were allowed some kind of right. We used our power over them constantly and violently, but stopped short of telling ourselves that creatures of alien biology could not be sentient or that they were incapable of true suffering and pleasure. Needing their bodies, we killed them in spite of those things.

Only with the Greeks does there enter the notion of a formal divide between our species, our animal, and every other on earth. Today in Greece you can walk by a field and hear two farmers talking about an alogo, a horse. An a-logos. No logos, no language. That’s where one of their words for horse comes from. The animal has no speech; it has no reason. It has no reason because it has no speech. Plato and Aristotle were clear on that. Admire animals aesthetically, perhaps, or sentimentally; otherwise they’re here to be used. Mute equaled brute. As time went by, the word for speech became the very word for rationality, the logos, an identification taken up by the early Christians, with fateful results. For them the matter was even simpler. The animals lack souls. They are all animal, whereas we are part divine. 

Who sleepeth with dogs shall rise with fleas.

- John Florio, 1578

And yet, if you put aside church dogma, and lean in to look at the Bible itself, or at the Christian tradition, the picture is more complicated. In the Book of Isaiah, God says that the day will come when the beasts of the field will “honor” Him. If there’s a characteristic of personal identity more defining than the capacity to honor, it’s hard to come up with. We remember St. Francis, going aside to preach to the little birds, his “sisters.” Needless to say he represented a radical extreme, conclusions of which regarding the right way of being in the world would not seem reasonable to most of the people who have his statue in their gardens. In one of his salutations, that of virtues, he goes as far as to say that human beings desiring true holiness should make themselves “subject” to the animals, “and not to men alone, but also to all beasts.” If God grants that wild animals eat you, lie down, let them do “whatsoever they will,” it’s what He wanted.

Deeper than that, though, in the New Testament, in the Gospel According to Luke, there’s that exquisite verse, one of the most beautiful in the Bible, the one that says if God cares deeply about sparrows, don’t you think He cares about you? One is so accustomed to dwelling on the second, human, half of the equation, the comforting part, but when you put your hand over that and consider only the first, it’s a little startling: God cares deeply about the sparrows. Not just that, He cares about them individually. “Are not five sparrows sold for two pennies?” Jesus says. “Yet not one of them is forgotten in God’s sight.” Sparrows are an important animal for Jesus. In the so-called Infancy Gospel of Thomas, a boy Jesus, playing in mud by the river, fashions twelve sparrows out of clay—again the number is mentioned—until a fellow Jew, happening to pass, rebukes him for breaking the Sabbath laws (against “smoothing,” perhaps), at which point Jesus claps and says, “Go!”, and the sparrows fly away chirping. They are not, He says, forgotten. So God remembers them, bears them in mind. Stranger still, He cares about their deaths. In the Gospel According to Matthew we’re told, “Not one of them will fall to the ground apart from your Father.” Think about that. If the bird dies on the branch, and the bird has no immortal soul, and is from that moment only inanimate matter, already basically dust, how can it be “with” God as it’s falling? And not in some abstract all-of-creation sense but in the very way that we are with Him, the explicit point of the verse: the line right before it is “fear not them which kill the body, but are not able to kill the soul.” If sparrows lack souls, if the logos liveth not in them, Jesus isn’t making any sense in Matthew 10:28–29. The passage may make no sense anyway. The sparrow population shows little sign of divine ministrations: two years ago the Royal Society for the Protection of Birds placed house sparrows on its “Red List” of globally threatened species. Charles Darwin [London, page 55] supposedly said that the suffering of the lower animals throughout time was more than he could bear to think of. That feels, if slightly neurotic, more scrupulously observed.


The modern conversation on animal consciousness proceeds, with the rest of the Enlightenment, from the mind of René Descartes, whose take on animals was vividly (and approvingly) paraphrased by the French philosopher Nicolas Malebranche: they “eat without pleasure, cry without pain, grow without knowing it; they desire nothing, fear nothing, know nothing.” Descartes’ term for them was automata—windup toys, like the Ren­aissance protorobots he’d seen as a boy in the gardens at Saint-Germain-en-Laye, “hydraulic statues” that moved and made music and even appeared to speak as they sprinkled the plants. This is how it was with animals, Descartes held. We look at them—they seem so full of depth, so like us, but it’s an illusion. Everything they do can be attached by causal chain to some process, some natural event. Picture two kittens next to each other, watching a cat toy fly around, their heads making precisely the same movements at precisely the same time, as if choreographed, two little fleshy machines made of nerves and electricity, obeying their mechanical mandate. 

Descartes’ view drew immediate controversy. Writers such as the naturalist John Ray, in The Wisdom of God Manifested in the Works of the Creation (1691), protested on behalf of “the common sense of mankind” that if “beasts were automata or machines, they could have no sense, or perception of pleasure, or pain…which is contrary to the doleful significations they make when beaten, or tormented.” A view with which most of us can sympathize, but one that rests to a regrettable extent on naked anthropomorphism—their screams sound like ours, and so must mean the same thing.

Buffalo chased by its keeper, Mughal drawing, southern India, c. 1700.

Buffalo chased by its keeper, Mughal drawing, southern India, c. 1700. © British Library Board. All Rights Reserved © The Bridgeman Art Library. 

Thomas Hobbes, writing soon after Descartes’ death, proposed more philosophically salient qualifications to Descartes’ theory. First, he points out, there is more overlap between us and the beasts than Descartes allowed. Beasts have memory (they can learn sequences of events, avoiding negative outcomes), and they can at least engage with speech (dogs learn our commands). Hobbes even claims—somewhat vaguely—that beasts possess a form of imagination brought about “by words or other voluntary signs,” one that we “generally call understanding.” What they don’t have, he says, is an understanding of their own “conceptions and thoughts.” They are not self-conscious. They are not, as we might put it today, “meta.” Hobbes identifies this self-consciousness as the divine spark.

Hobbes’ contemporary, the Dutch Jewish philosopher Baruch Spinoza, hesitated to make even that kind of essential distinction between us and them. The difference was rather one of degree, or more than that, one of kind. He writes in Ethics,

Hence it follows that the emotions of the animals which are called irrational…only differ from man’s emotions to the extent that brute nature differs from human nature. Horse and man are alike carried away by the desire of procreation, but the desire of the former is equine, the desire of the latter is human…Thus, although each individual lives content and rejoices in that nature belonging to him wherein he has his being, yet the life, wherein each is content and rejoices, is nothing else but the idea, or soul, of the said individual…It follows from the foregoing proposition that there is no small difference between the joy which actuates, say, a drunkard, and the joy possessed by a philosopher.

Apart from the general point—horses feel horse joy, cats feel cat joy, etc.—Spinoza makes two less familiar but equally significant claims. The first is his lovely definition of the soul: that it is in some way wrapped up with, coextensive with, the “essence” of the creature possessing it. The particular nature in which every creature is able to rejoice precisely by being most entirely itself is the soul. That settles the matter of whether animals have souls. Of course they do. The horse has a horse soul, the fish has a fish soul. The second claim is Spinoza’s radical—but instantly persuasive—statement that one human being’s essence could be unintelligible to another. The drunkard is a different type of human being than the philosopher, but he is also a different creature, full stop. Are we so sure that species identification is proof against the canyons of misapprehension that separate us from, say, the monkey spider? This could be a frightening thought: accepting that no two consciousnesses can ever have transparency, or at any rate can never have certainty about it, leaves us on some level cosmically alone. Spinoza takes the notion in stride. He’d be more prone to say, Well, no doubt we sometimes understand each other.

Suprisingly, perhaps, these thoughts did not lead Spinoza to a recommendation of total empathy with the animal kingdom, as the animal-rights activist in us would hope. He is fairly cold-eyed, even cold-hearted, writing,

It is plain that the law against the slaughtering of animals is founded rather on vain superstition and womanish pity than on sound reason. The rational quest of what is useful to us further teaches us the necessity of associating ourselves with our fellow men, but not with beasts, or things, whose nature is different from our own; we have the same rights in respect to them as they have in respect to us. Nay, as everyone’s right is defined by his virtue, or power, men have far greater rights over beasts than beasts have over men. Still I do not deny that beasts feel: what I deny is that we may not consult our own advantage and use them as we please, treating them in the way which best suits us; for their nature is not like ours.

In order to understand this, we have to know something about Spinoza’s definition of fundamental or natural right, which comes very close to meaning, simply, power. We have the right to do with them “as we please,” just as they have the “right” to eat us, if the meeting happens on ground more favorable to them. Spinoza isn’t trying to argue that we shouldn’t act kindly toward them, when we can, but he does imply that we needn’t feel guilty about it, when we treat them violently. It’s our right. It suits us. 


The whole “animal consciousness” problem remained more or less static for the next two hundred years. Which is to say, it remained philosophical, and retained more or less the contours of the dispute as it had existed among Descartes and his contemporaries, one side arguing that animals did not possess reason or the capacity for meaningful self-awareness, the other countering that we really have no idea what they think, and given that they often seem to undergo states equivalent to our own, why shouldn’t we assume that they do? After all, absence of proof isn’t proof of absence. But it isn’t proof of presence, either, and that’s what science wants. 

There were flashes. Scattered experiments on animal behavior began to occur around the 1780s, and, of course, throughout the nineteenth century an enormous amount of direct observation was taking place—people were bumping up against the question more than ever. But mostly it was like arguing about the existence of life on other planets, or some other topic considered inescapably mysterious. 

In On the Origin of Species, Darwin made the intriguing claim that among the naturalists he knew it was consistently the case that the better a researcher got to know a certain species, the more each individual animal’s actions appeared attributable to “reason and the less to unlearnt instinct.” The more you knew, the more you suspected that they were rational. That marks an important pivot, that thought, insofar as it took place in the mind of someone devoted to extremely close and meticulous study of living animals, a mind that had trained itself not to sentimentalize. Even at so intimate a range of scrutiny, looking not just at apes and dogs but also at birds and worms, Darwin rediscovered that feeling, which even children know. Or which children believe, as a mechanist might say.

Satyr Mourning over a Nymph, by Piero di Cosimo, c. 1495.

Satyr Mourning over a Nymph, by Piero di Cosimo, c. 1495. National Gallery, London. 

It’s Darwin who finally wrenches these questions away from the salon and into the lab, where they’ve mostly stayed. We stand now at the end of a century’s intense scientific research on the interiors of animal minds—it’s been roughly a hundred years since the publication of Edward L. Thorndike’s Animal Intelligence (1911). Thorndike, a psychologist at Columbia University, designed the famous “puzzle boxes,” from which he challenged poor cats to escape, concluding that they possessed a kind of reward-and-repeat mechanism but not what he called “insight” (suggesting among other things that vagueness of terms has been a hereditary pitfall of the field). 

The sheer number and variety of experiments carried out in the twentieth century—and with, if anything, a renewed intensity in the twenty-first—exceeds summary. Reasoning, language, neurology, the science of emotions—every chamber where “consciousness” is thought to hide has been probed. Birds and chimps and dolphins have been made to look at themselves in mirrors—to observe whether, on the basis of what they see, they groom or preen (a measure, if somewhat arbitrary, of self-awareness). Dolphins have been found to grieve. Primates have learned symbolic or sign languages and then been interrogated with them. Their answers show thinking but have proved stubbornly open to interpretation on the issue of “consciousness,” with critics warning, as always, about the dangers of anthropomorphism, animal-rights bias, etc. 

Regardless, though, of whether they can talk to us, we’ve learned more and more about the complex ways in which they talk to each other. Entomologists mastered the dance code of the bees and spoke it to them, using a tiny bee-puppet. (For the bees it may have been as if the puppet had a strange accent). In more recent years the numerous calls that elephants make to one another across 150-mile distances have been recorded and decoded. Evidently the individual animals can tell each other apart. So there are conversations of some kind taking place. Zoologists have observed elephants having, for instance, a “departure conversation” at a watering hole, rustling their great heads together in a “rumbling,” communicating about the decision to leave; the water is no good here, we should move on. Who knows what they’re saying. Ludwig Wittgenstein said that if a lion could talk, we wouldn’t understand it. It may, as it turns out, be truer to say that we wouldn’t understand it very well.

If we put aside the self-awareness standard—and really, how arbitrary and arrogant is that, to take the attribute of consciousness we happen to possess over all creatures and set it atop the hierarchy, proclaiming it the very definition of consciousness (Georg Christoph Lichtenberg wrote something wise in his notebooks, to the effect of: only a man can draw a self-portrait, but only a man wants to)—it becomes possible to say at least the following: the overwhelming tendency of all this scientific work, of its results, has been toward more consciousness. More species having it, and species having more of it than assumed. This was made boldly clear when the “Cambridge Declaration on Consciousness” pointed out that those “neurolog­ical substrates” necessary for consciousness (whatever “consciousness” is) belong to “all mammals and birds, and many other creatures, including octopuses.” The animal kingdom is symphonic with mental activity, and of its millions of wavelengths, we’re born able to understand the minutest sliver. The least we can do is have a proper respect for our ignorance. 

The righteous know the needs of their animals, but the mercy of the wicked is cruel.

- Book of Proverbs, 500 BC

The philosopher Thomas Nagel wrote an essay in 1974 titled, “What Is It Like To Be a Bat?”, in which he put forward perhaps the least overweening, most useful definition of “animal consciousness” ever written, one that channels Spinoza’s phrase about “that nature belonging to him wherein he has his being.” Animal consciousness occurs, Nagel wrote, when “there is something that it is to be that organism—something it is like for the organism.” The strangeness of his syntax carries the genuine texture of the problem. We’ll probably never be able to step far enough outside of our species-reality to say much about what is going on with them, beyond saying how like or unlike us they are. Many things are conscious on the earth, and we are one, and our consciousness feels like this; one of the things it causes us to do is doubt the existence of the consciousness of the other millions of species. But it also allows us to imagine a time when we might stop doing that.

In Michel de Montaigne’s excellent passage on animal minds in the “Apology for Raymond Sebond” [Aquitaine, page 111], in which he writes about playing with his cat and wonders who is playing with whom, there is a funny and deceptively profound final sentence: “We divert each other with monkey tricks,” he writes. Meaning he and the cat. Both human being and cat are compared with a third animal. They are monkeys to each other, strange animals to each other. (The man is all but literally a monkey to the cat.) All three creatures involved in Montaigne’s metaphor are revealed as points on a continuum, and none of them understands the others very well. This is what the study of animal consciousness can teach us, finally—that we possess an animal consciousness. 

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