What sorts of philosophical problems do we face because of the existence of non-human animals? Most humane people would agree that their existence presents us with some moral and legal quandaries. And recently, but only recently, philosophers have taken a serious interest in the character of animal minds. But I have come to think that animals present us with a philosophical problem deeper than either of those—that the existence of non-human animals is the source of a profound disturbance in the way that human beings conceptualize the world. It is almost as if we—I’m using “we” to mean “us human beings” here—are unable to get them firmly into view, to see them for what they really are.

Many people, to take one small example, find nothing odd about the sentence, “I live alone with a cat.” Okay, granted, someone might also say, “I live alone with a child,” at least so long as the child was a very small one. But “I live alone with four children” would be starting to put the language under stress, even if they were all toddlers, while “I live alone with four cats” would not. Here’s another example: People wondering about whether there might be life on other planets sometimes ask, “Are we alone in the universe?” Just look around!

Well, you may reply, they mean to ask whether there is any other intelligent life in the universe. Right. Just look around! Animals also seem to pop in and out of our moral view. Most people would agree that it is wrong to hurt or kill a non-human animal without a good reason, but then it turns out that any reason, short of malicious pleasure, is reason enough. We want to eat the animal, and to raise her cheaply for that purpose; we can learn from doing experiments on her; we can make useful or attractive products out of her; she is interfering with our agriculture or gardening; or maybe we just don’t feel comfortable having her come so near. Her interests have weight, we insist—but never weight enough to outweigh our own.

Then there is the disturbing use of the phrase “treated like an animal.” People whose rights are violated, people whose interests are ignored or overridden, people who are used, harmed, neglected, starved or unjustly imprisoned standardly complain that they are being treated like animals, or protest that after all they are not just animals. Of course, rhetorically, complaining that you are being treated like an animal is more effective than complaining that you are being treated like a thing or an object or a stone, for a thing or an object or a stone has no interests that can be ignored or overridden. In the sense intended, an object can’t be treated badly, while an animal can. But then the curious implication seems to be that animals are the beings that it’s all right to treat badly, and the complainant is saying that he is not one of those.

Do we need that contrast, between the beings it is all right to treat badly and the ones it is not? My otherwise favorite philosopher, Immanuel Kant, seemed to think so. In his essay “Conjectures on the Beginning of Human History,” Kant traces the development of reason through a series of steps, the last of which is this:

The fourth and last step which reason took, thereby raising man completely above animal society, was his … realization that he is the true end of nature … When he first said to the sheep ‘the pelt which you wear was given to you by nature not for your own use, but for mine’ and took it from the sheep to wear it himself, he became aware of a prerogative which … he enjoyed over all the animals; and he now no longer regarded them as fellow creatures, but as means and instruments to be used at will for the attainment of whatever ends he pleased. This notion implies … an awareness of the following distinction: man should not address other human beings in the same way as animals, but should regard them as having an equal share in the gifts of nature. … Thus man had attained a position of equality with all rational beings, because he could claim to be an end in himself … and not to be used by anyone else as a mere means to other ends.

Non-human animals, on this showing, are the ultimate and final Other. They are the beings we can still use as mere means once we have given up the idea that other human beings are there for our purposes—once we’ve rejected the ideas that women are for housework and childcare, that girls are for sex, that boys are for fighting wars that serve older men’s interests, and that people of color are for harvesting the fields and doing the menial jobs that all of us hate. Is that, to revert to this symposium’s theme, what animals are for? Are they there so that there will be someone we can still use as mere means to our ends?

Not being what Kant called a “mere means” is not a privative condition—a way of being useless, say. It’s a positive condition, which Kant calls being an “end in yourself.” For a human being, it means that your choices should be respected and your ends promoted, that you have rights that the community should be prepared to uphold, that your happiness is valuable and your suffering should be cured or mitigated or met with tenderness when it is beyond cure. “Morality” is our name for demanding this kind of treatment from one another, and for meeting that demand. When we do use others to serve our own purposes— for of course we do—it must be done in a way that is consistent with all this, and then we are not treating them as “mere means,” but at the same time as ends in themselves. But why shouldn’t the other animals also be treated as ends in themselves?

I’ll come back to that question. But first, let me respond to those readers who are now tempted to protest that there are plenty of people who do treat the other animals as ends in themselves. After all, it is notorious these days that more people than ever not only live with companion animals, but treat them like human children, keeping them in the house, providing them with toys and furniture, buying them medical insurance, bribing their affection with treats and burying them in graveyards when they die. Of course it’s also true that in tough economic times when there is no longer money for such indulgences, these companion animals are turned loose onto the streets and into shelters in a way that human children ordinarily are not. But even those of us who are convinced that we would never treat our beloved pets in this way should remember that keeping an animal for affection and companionship is also a way of using the animal. Is it using the animal as a “mere means”?

It could be. Even among people, of course, it is possible to use someone for affection and companionship without keeping her existence and value as an independent being firmly in view. In Middlemarch, George Eliot tells the story of Dorothea, an idealistic young woman hungry to do some good in the world, who marries an older man whom she conceives to be a scholar engaged in a great work. Eliot writes:

We are all of us born in moral stupidity, taking the world as an udder to feed our supreme selves: Dorothea had early begun to emerge from that stupidity, but yet it had been easier to her to imagine how she would devote herself to Mr. Casaubon, and become wise and strong in his strength and wisdom, than to conceive with that distinctness which is no longer reflection but feeling—an idea wrought back to the directness of sense, like the solidity of objects—that he had an equivalent center of self, whence the lights and shadows must always fall with a certain difference.

Eliot’s purpose, at the particular moment at which this passage occurs, is to emphasize that Dorothea has failed to understand Casaubon’s feelings. She has not quite managed to get his “center of self” into her view. But the moment is also one of moral revelation, a moment in which Dorothea grasps that “there is as great a need on his side as on her own” and so acquires “a new motive.” Eliot is accusing her heroine, just a little, of having used Casaubon as a mere means to give significance and purpose to her own life. How much easier, then, to do something like that to a creature whose “center of self” you may not—rightly or wrongly—grant to be the “equivalent” of your own.

Is it because the other animals have lesser “centers of self” that so many people suppose they are not entitled to be treated as ends in themselves? In his Tanner Lectures, written as a work of fiction called The Lives of Animals, J. M. Coetzee imagines a professional philosopher who says: “It is licit to kill animals because their lives are not as important to them as ours are to us.” George Eliot reminds us how hard it is to keep in view—not just to tell yourself, but to feel with “the directness of sense”—that other people’s lives are as just important to them as yours is to you. But we are at least theoretically committed to the importance, and the equal importance, of every human life. Many of our religious and philosophical traditions try to explain this equal importance. We, these traditions assert—we human beings, that is—are all God’s children, or have some special sort of intrinsic value that the other animals lack. But what makes it possible to believe such things at all is probably the thing that Coetzee puts in his philosopher’s mouth: the passionate sense of importance that each of us attaches to himself or herself. After all, every human being pursues the things that are important to himself and to those whom he loves as if they were important absolutely, important in deadly earnest—for what else can we do? And just by doing that, we claim our own standing as ends in ourselves. For when we claim that the things that are important to us should be treated as important absolutely, just because they are important to us, we also claim that we are important ourselves. But the other animals also pursue the things that are important to them and their loved ones as if they were important in deadly earnest. Why then should we think they must be less important to themselves than we are to ourselves?

Some of the philosophical views about the nature of animal minds are, among other things, attempts to answer that question. The other animals are not conscious at all, some people argue, or their consciousness is so fleeting and ephemeral that it just does not add up to the consciousness of a self, so nothing really could matter to them in quite the same that way it does to us. A less extreme version of that last view—one that even many defenders of the moral claims of animals, such as Peter Singer, endorse—is that animals live so thoroughly in the moment that their deaths are not regrettable, although their suffering is.

That might seem puzzling. After all, when we consider our fellow human beings, we often regard a capacity for living in the moment as a good thing. The human mind can be so cluttered and overshadowed with worries about the future and regrets about the past that we fail to enjoy the present—the only thing, after all, that is real. So why would the fact that the other animals live in the moment, supposing it is a fact, make their deaths less regrettable? Jeff MacMahan offers this explanation:

… the lives of persons typically have a narrative structure that may demand completion in a certain way. People autonomously establish purposes for their lives, form patterns of structured relations with others, and thereby create expectations and dependencies that require fulfillment. The importance of later events in a typical human life may thus be greatly magnified by their relation to ambitions formed and activities engaged in earlier … In the lives of animals, however, this potential for complex narrative unity is entirely absent. There are no projects that require completion, mistakes that demand rectification, or personal relations that promise to ripen or mature. Rather, as Aldous Huxley once put it, “the dumb creation lives a life made up of discreet and mutually irrelevant episodes.” And each day is merely more of the same.

According to this argument, to deprive a human being of life is worse than to deprive another animal of life, because you are depriving the non-human animal only of “more of the same,” while you may be disrupting the narrative unity of the human being’s life.

I have mixed reactions to this kind of argument. On the one hand, animal lives are not the same every day—rather, at least for many of them, they have a rhythm that is set by the seasons of the year, and by the age of breeding, and may involve the raising of families, migrations, the building of homes, preparation for the winter and so on. Many mother animals raise new young every year or so, and most of those die and presumably are forgotten, but in some social animals, the bonds that result from family ties are permanent and important. Relationships, families and larger social groups persist over time. For some animals there is even a narrative structure to the course of an individual life that we can recognize and describe—even if they cannot. Among social animals, for instance, certain male individuals rise to positions of power and leadership in middle age, only to be deposed by younger members when they are older. Females move through a distinct set of roles in family life as daughters, then mothers, then grandmothers in much the same way that, in many cultures, human females do.

Which brings me to the other side of what bothers me about this—that human lives also have established rhythms set by the seasons of the year and the age of breeding, and that many human lives, especially when you look at the species historically, or at less developed nations, have been pretty much the same every day. You get up, do some work, eat breakfast, then do some more work. You tend the children and prepare the food, or you feed the animals, or you hoe the fields, or you go to the factory, depending on when and where your life takes place, but you go to work, and then you have supper, and then go to bed and start over. Each day is merely more of the same. Perhaps it is exactly those lives that most challenge the ability of the more privileged members of developed nations to feel with “the directness of sense” that every person’s life is just as important to her as ours are to us.

Yet there is clearly something right about MacMahan’s picture. I think it is this: we human beings, unlike the other animals, think of ourselves and our lives in normative terms. We are governed not merely by instinctive likes and dislikes, attractions and aversions, enjoyment and suffering, but by values. Being reflective animals, we endorse or reject our likes and dislikes, attractions and aversions, pleasures or pains, declaring them to be good or bad. Each of us identifies himself in terms of certain roles, relationships, occupations and causes, all of them governed by normative standards, which it is then the business of our lives to live up to. And so we come to think of ourselves as worthy or unworthy, lovable or unlovely, good or bad.

Philosophers disagree about what exactly it is about our nature that makes us like this— whether it is rationality, or a special kind of sentiment, or something else. However that may be, this kind of evaluative self-conception is a condition that gives a strange extra dimension to human life, both a special source of pride and interest, and a profound cause of suffering. It is not that nothing is important to the other animals, for instinctive desire and aversion have an imperative character all their own. But that does not seem to suffuse whatever sense of their own being the other animals have. Some of the other animals seem to have moments of pride, but they don’t seem in general to think of themselves as worthy or unworthy beings. Some of them certainly want to be loved, but they don’t seem to worry about being lovable. Thinking of yourself as having a kind of identity that is at once up to you and subject to normative assessment is a distinctive feature of being human. It gives a human being’s life, in his own eyes, the character of a project, of something at which he can succeed or fail. That possibility of success or failure is what gives human life the kind of narrative structure that MacMahan describes.

If this is right, it shows that human lives are important to human beings in a way that the lives of the other animals are not important to them. But it does not show that our lives are more important than theirs. It is not that our lives have a kind of importance that the lives of the other animals lack. It is rather that our lives have a kind of importance for us that the other animals’ lives do not have for them. And I am prepared to make a further claim here: that there is nothing that is therefore missing from the lives of the other animals.

This is where things start to get a little bit dizzying, conceptually speaking. The difficulty is that everything that is important must be important because it is important to someone: to some person or animal. What makes it important to that person or animal is that it satisfies some desire or conforms to some standard that applies to that person or animal. But the standard of normative success and failure, which goes with the project of making yourself into a worthy or an unworthy being, does not apply to the other animals. There is nothing missing from the lives of the other animals because they fail to see themselves as good or bad, successes or failures. The standards that we use when we measure ourselves in these ways apply to us in virtue of something about our nature, and do not apply to them.

Perhaps a comparison will help. John Stuart Mill famously claimed that it is better to be Socrates dissatisfied than a pig satisfied. Mill believed this because he held that human beings have access to what he called “higher pleasures”—for instance, the pleasures of poetry. But for whom is it better? Would it be better for the pig if he were Socrates? Temple Grandin, in her book Animals Make Us Human, reports that there is nothing pigs love more than rooting around in straw. Poetry is not good for a pig, so it is not something valuable that is missing from the pig’s life, something he would get access to if he were changed into Socrates, any more than rooting around in straw is something valuable that is missing from your life, something you would get access to if you were changed into a pig. But isn’t poetry a higher pleasure than rooting around in straw? If what makes a pleasure “higher” is, as Kant and others have suggested, that it cultivates our capacity for even deeper and greater pleasures of the very same kind, then we must have that capacity before the pleasure can be judged a higher one for us. Since the pig lacks that capacity, poetry is not a higher pleasure for a pig. Of course, we might try the argument that, so far as we can tell, none of the pig’s pleasures are “higher” in this sense. But then perhaps it is only for us jaded human beings that the lower pleasures seem to grow stale. So long as the straw itself is fresh, pigs apparently never lose their enthusiasm for rooting around in straw.

There’s a notorious philosophical problem about thoughts that begin, “if I were you…” When I tell you what I would do if I were you, I must bring something of myself with me, usually some standard for the assessment of actions that also applies to you, or a superior ability to apply some standard that we already share. Otherwise it’s a foregone conclusion that whatever you would do if I weren’t offering you advice is exactly what I would do if I were you. But the standard I bring with me may be one that does not apply to you or that you do not share. David Hume reminds us of the famous story of the advice Parmenio gave to Alexander the Great. “Were I Alexander, said Parmenio, I would accept of these offers made by Darius. So would I too, replied Alexander, were I Parmenio.” This problem pervades our efforts to think about the other animals, for when we try to think about what it is like to be another animal, we bring our human standards with us, and then the other animals seem to us like lesser beings. A human being who lives a life governed only by desires and instincts, not by values, would certainly be a lesser being. But that doesn’t mean that the other animals are lesser beings. They are simply beings of a different kind. When we look at the other animals through the lens of our own standards, just as when we look at them through the lens of our own interests, we cannot get them properly in view.

We are all born, as Eliot says, in moral stupidity, unable to see others except through the lens of our own interests and standards. Kant suggested that it took four steps for us to emerge from this moral stupidity, but perhaps there is a fifth step we have yet to take. That is to try to look at the other animals and their lives unhindered by our own interests and specifically human standards, and to see them for what they really are. What is important about the other animals is what we have in common: that they, like us, are the kinds of beings to whom things can be important. Like us, they pursue the things that are important to them as if they were important absolutely, important in deadly earnest—for, like us, what else can they do? When we do this, we claim our own standing as ends in ourselves. But our only reason for doing that is that it is essential to the kinds of beings we are, beings who take their own concerns to be important. The claim of the other animals to the standing of ends in themselves has same ultimate foundation as our own—the essentially self-affirming nature of life itself.