As part of our ongoing event series with The Philosopher, Jeremy Bendik-Keymer sat down with Martha Nussbaum, Ernst Freund Distinguished Service Professor of Law and Ethics at the University of Chicago, to discuss her new book, Justice for Animals: Our Collective Responsibility. In the course of their conversation, they discuss animal sentience and capabilities, Nussbaum’s collaboration with her late daughter Rachel, the evolution of animal ethics within philosophy, and much more. Below is a transcript of their conversation, which has been edited for clarity and concision.

Learn more about our Fall 2022 philosophy event series here.

Anthony Morgan: How can we create a world in which human beings are truly friends of animals, rather than exploiters or users? The world needs an ethical awakening, a consciousness movement of international proportions. The context for this event is the publication of Martha Nussbaum’s new book, Justice for Animals: Our Collective Responsibility.


Jeremy Bendik-Keymer: This is an incredibly rich book, Martha. You write in the introduction:

For me this book is a work of love and, now, of what I might call constructive mourning—attempting to carry forward the commitments of a person the world has tragically lost. My daughter, Rachel Nussbaum, was my mentor and inspiration as I began, relatively late in life, to take a keen interest in the plight of non-human animals. [This book] looks forward, attempting to further the causes she loved with a theory she knew about and supported. This theory, a version of my capabilities approach, measures justice by asking whether people (or, in this case, sentient animals) have been enabled by laws and institutions to live a decently flourishing life, as defined by a list of opportunities for choice and activity that the creature has (or lacks) in its political and legal context.

What questions guided this book and drove you through the process? What did you learn from writing it?


Martha Nussbaum: For years I’ve been very dissatisfied with the two dominant theories that direct our practical efforts in the animal area. The first is what I call the “So Like Us” approach—the anthropocentric approach of the Nonhuman Rights Project and Steven Wise. This approach has directed lots of litigation, but it judges the worthiness of animals by their likeness to humans. The second, which is a lot better but still not quite right, is the utilitarian theory of Peter Singer, and before him, Jeremy Bentham and John Stuart Mill, which focuses on pain as the single bad thing. I think this view flattens the world too much, leaving out the many things that animals are trying to do, such as social life, moving around in a large space, play, and interspecies relationships.

Animals are not passive; they can be participants in the political community.

I wanted to argue that my version of the capabilities approach would be a better guide, because it focuses on the idea that minimal justice is achieved only when a creature, in this case each variety of animal, has the opportunity to live a flourishing life of that species’ own kind. This theory corresponds to what good scientists and sensitive judges are already doing. But I wanted to spell it out, and rigorously set it forth and give the arguments for and against the different views.

Along the way, I had to include a lot of science to say what sentience is—what creatures are included in this view. I had to talk about the tragic conflicts we get when the goods of one species are pitted against the goods of others. I had to devote separate chapters to companion animals and to wild animals. And then, finally, I had to try to say something about the inadequacy and shortcomings of law and where law should be going. What did I learn? Well, that was the great joy of writing this book: I read a huge amount of science. And in the last three years, there’s really been a tremendous deepening of our knowledge of animal lives; so I learned so much.


JBK: There’s also a portion of the book that’s focused on Christine Korsgaard’s work, which you admire quite a bit.


MN: Korsgaard’s Fellow Creatures: Our Obligations to the Other Animals (2018) is a stunning book. I agree with quite a lot of it, because she discards a lot of the bad views of the historical terms, and she develops her own view, from both Kantian and Aristotelian material. I think toward the end of the book, she comes back, to my mind, too much to Kant in that she says that because we’re the only creatures capable of ethical deliberation, we’re the only ones who can be active citizens on behalf of animals. Now, she clearly doesn’t think this makes us better. She refuses all such ranking. But she does think it makes us the only ones who can take an active step politically to defend the rights of animals.

But I say, look: animals are speaking all the time about what they want and what they don’t want. Their behavior and their languages indicate so much about their preferences. After all, with human children and people with cognitive disabilities, we don’t have to wait until they can speak fluent English or whatever language. We listen to them, and we look at them, and we see what they’re indicating by their behavior. We should be doing the same for animals. Animals are not passive. They can be participants in the political community.


JBK: How does this book relate to your philosophical work? Does it have ties to work you’ve done in the past? And why did you feel the need to do this work now, beyond your allegiance to your daughter, Rachel?


MN: I think it does go back to my doctoral dissertation on Aristotle’s De Motu Animalium, because he said that we really need a common explanation for the movement of both humans and other animals towards their goals: that whatever the differences are, there’s a common framework that all creatures use forms of perception and forms of desire to get going, to move towards their objects of desire. It’s obvious that it goes back to my first writings on the capabilities approach in Women and Human Development (1999), Frontiers of Justice (2006), which has a chapter on animals, and finally Creating Capabilities (2011). But I think it also goes back to my work on emotions, because I do talk about wonder and compassion. My work hangs together, I think, around the issue of seeing living beings as vulnerable to accidents beyond their control. And my work on emotion says that emotions are ways of getting in touch with the goods outside ourselves that we don’t control, and that they’re valuable in practical reasoning and valuable in life because they do put us in touch with what it is to have or lose or find threatened a good thing ourselves that we don’t control. All of the emotion work hangs together with the capabilities approach to this idea of vulnerability: capabilities are things that need to be protected because we’re vulnerable beings. We don’t automatically have life, bodily integrity, bodily health, and all the other things on my capabilities list. But we need those spaces to be protected for us precisely because of our vulnerability.

Why now? The world has gotten to a point where I think it is ready to hear about this. There’s so much going on, and I hear every day from people who are, for the first time, feeling a passion to do something for animal rights. But I also feel that science has taken such strides that now we can no longer say, “Oh, birds are stupid,” or whatever. We know too much. And people are really interested in the science, too. Scientists have written very well, and they have used wonderful books with pictures and so forth, so we can learn. Now, we have no excuse to be behind the learning that is available to us.


JBK: I don’t think I’ve read a book of yours that is so far-reaching in the way that it characterizes domination in the world. The picture in this book is one of a world where animals everywhere live directly or indirectly dominated by human societies. And you have a problem with that.


MN: I wanted people to understand that there is no space on the land, in the sea, and in the air, that’s not dominated by human beings. On the land, the most free that animals are is in a large wildlife refuge that’s policed and tended—if it’s tended well—by human beings in an African nation. I think people think the seas are a great bastion of wildness and freedom. In fact, they’re full of things that human beings have put there. Plastic. There are whales dying because they swallow plastic trash: a whale was found dead with eighty-eight pounds of plastic trash calcified into a plastic brick in its stomach. But also, the pollution of sound. Whales and other marine mammals negotiate the world much more by sound than by sight or smell. And it is not just sonar programs that are responsible for pollution. Actually, the U.S. Navy’s low-frequency sonar program has been declared illegal now by a very good judgment, that I talk about quite a lot in the book, which says it has an adverse impact on the life activities of whales. But that’s only in the coastal waters. Out in the wild, so to speak, oil companies are trying to drill. And before they can decide where they’re going to drill, they have to figure out what the cartography of the ocean floor is. And they send air guns down to the ocean floor, and of course, this has a terrible effect on the migration patterns, the reproduction, the energy, and the emotional stability of marine mammal population.

Each animal should have the opportunity to live a flourishing life of that species’ own kind.

In the air, about half the migratory species that we have are threatened now. One big threat is air pollution. Another is buildings. Last spring, there was a shift in the migration route of some species of birds. They started crashing into our building, and dead birds were found all over the place. So that’s what we do. And we can stop it, but we just don’t take care. The point is that human beings are negligent. And they’re not always malignant—they don’t always intend to cause harm. But negligence is also a crime. We’re a very negligent species because we just don’t know what’s going on.


JBK: What was it like to collaborate on substantial parts of this work with Rachel? And how did the work you did together relate to her vocation and purpose? How would she hope that we develop the work that you two did?


MN: Rachel had a passion for whales and other marine mammals. We wrote four articles together. One was a general point about what goes beyond utilitarianism: What do we need in a theory that goes beyond utilitarianism? The second was about the complaint that some practitioners of harpoon whaling make: that it destroys the life of indigenous people. The third addresses the other Japanese complaint: that they think there’s scientific knowledge that requires killing whales. And the last was in a symposium at the Journal of Human Development and Capabilities about friendship between human beings and other animals. That was more general; it wasn’t just about whales. She supplied the law from the papers she’d already written, which we had to then rewrite, and I supplied the capabilities approach philosophy. But we had a lot of fun doing it. She would come to the meetings of the Human Development and Capability Association (HDCA). We tried to convince the other members of that association to take these issues to heart—not always successfully. They often thought, “Oh, human beings are so much in need that we really should focus on human beings.” But we tried hard: we would enjoy shaking things up and making an inroad.


JBK: At one of the HDCA meetings, the one in Cape Town, there was quite an uproar that had to do with the concern that your focus on other animals would take people away from addressing pressing issues of human development. I’m wondering if you could say a little bit about this concern.


MN: I think there are certainly some genuinely tragic dilemmas in this area. I talk about some of those in my chapter on tragic dilemmas, where it does look like the two groups—animals and humans—are pitted in a kind of tragic way for life and sustenance. One might be elephants and African villagers. Elephants need tree bark to live, and they need all the kinds of things that are in villages. And of course, they’re not malevolent. Elephants are very gentle and harmless creatures. But they really do take things the villagers need.

My approach in all of these areas is to ask, what would a world be like in which those tragic dilemmas don’t arise anymore? What can we do to fix the world to, as Hegel would put it, aufheben the conflict? I think that’s one of the most difficult ones, because it really requires, first of all, limiting human populations. Let’s face it: these things arise because human beings are too numerous. And sometimes I think we might want to limit animal population where an animal can’t sustain itself in its given habitat. For example, we might need to use contraception to limit the elk population.

But for the most part, it’s the humans who need to adapt. And certainly not the elephants, because they’re an endangered species. People have gotten used to not taking animals seriously. They think that anything we do for animals will take away from us. I would like to say that a full development of our humanity requires developing our capacities to care for the world of nature and for the animals in it. And we should see it much more in positive terms than in zero-sum terms.


JBK: Thirty years ago, animal ethics was marginal in philosophy. Now it’s increasingly mainstream. Has your relationship to philosophy changed at all in the course of building towards, and then writing, this book over the last decades? And what about in your involvement with HDCA?


MN: I’ve always gravitated to philosophy, because I think of it as so rigorous, and I feel I grow much more in that field than I would in any other field that I’ve been attached to in one way or another. So I haven’t been alienated from the field. I’ve still felt philosophy is the source of the best critiques and the most rigorous theories. But I have thought it needs to change to make room not just for animals, but also for the voices of non-Western peoples and cultures. I think people are beginning to see how important it actually is, and I’m very, very glad to see this. So many good young people are coming along in philosophy, but also in law. My law students have become really enamored of this issue. I taught the book as a seminar, and they gave me such wonderful comments. And now they’re graduating this year. They’re doing things like stating pro bono programs at their law firms, and they’re really going to beef up the work. I think having a theory enabled them to feel that they could keep up the work as a part of their intellectual life, not just as a part of their philanthropy and their personal conduct.

By now, Amartya Sen and other prominent people in the HDCA do take the animal issue seriously. But there are people who don’t. And the economics profession, which is such a dominant profession, is a little bit slow to take up any new idea. People go into economics largely because they’re good at math these days, and they gain success because they’re good at math. Thinking normatively about a new issue is not really what they’re trained to do, and not really what they want to do. I’m really worried about the association. And look at that name: the Human Development and Capability Association. I proposed, and I’ve written, that we really should just call it the “Development and Capabilities Association.” It’s not just humans.


JBK: I want to ask a slightly more specific question that goes back to the first bit about Korsgaard. The discipline of philosophy has really privileged human exceptionalism and human superiority, usually by emphasizing the property or the capacity of reason. In political philosophy, it’s quite common to base theories of citizenship on the capacity to, say, deliberate. One of the things that’s surprising in your book and in your capabilities approach is that you push toward a broader form of intelligence, which you group under sentience.

You talk about how your theory of justice is dependent on the standard animal package in which, to put it simply, the animal wants to be sentient. It has a particular form of subjectivity. And in your critique of Korsgaard, the problem with the Kantian approach is it still won’t let go of the categorical distinctness of reasoning. And you develop a kind of continuum. You say we need to look at the continuum. And in your discussion of citizenship, you are quite strongly against, for example, environment ethicists like Steven Vogel, in talking about how animals actually make demands, and you just have to learn how to understand their communication. Could you say a little bit about what you’re doing with the hallowed category of reason, or if you want to flip it around, what you’re doing with animal sentience and citizenship?


MN: I think we have to learn much more science. We really have to see that animals are capable of many forms of reasoning and problem solving. I think one problem with Korsgaard is that she doesn’t seem aware of what scientists have discovered in the last thirty years. Animals are great problem solvers, and they also reason normatively. They solve ethical problems, they make peace, and they settle conflicts—often better than we humans do. The continuum includes a continuum in moral reasoning, and in the part of rationality that consists of having a variety of sophisticated emotions. Every biologist now who works on animals thinks they have emotions and that their emotions embody thoughts about good and ill. And that’s why they evolved. That’s why animals have them. We must first of all not weigh reason like a flag of separateness. We must understand how it permeates the animal world. But sentience means, to me—and it’s what it means for the biologists that I draw from—having somebody at home inside: in other words, having a distinctive perspective on the world.

We must not weigh reason like a flag of separateness: we must understand how it permeates the animal world.

Experiments now show that animals of all kinds have this property. Being able to feel pain is not the whole of it, of course. Having subjective perception is much broader than pain. But pain is the easiest thing to do experimental research on. And we now know that fish, for example, feel pain. Crustaceans are very much in dispute. Cephalopods do seem to have sentience: the octopus, the squid, and so on. But crustaceans, in dispute. And insects are very much in dispute. The consensus right now that insects do not have sentience. But whatever the empirics of it turn out to be, I think the crucial thing is the philosophical issue that having that ability really is a dividing line between creatures that are like someones and creatures that are not. Now, that doesn’t mean we can use the rest of nature in any old way, or that there’s no ethical imperative to treat the rest of nature well. I think there are many ethical reasons to treat nature well. But justice, to me, is a matter of having a striving being who is wrongfully thwarted in its striving. So that’s why sentience matters, because it’s a necessary condition of striving, so to speak. I think sentience is important, and I do not think that plants are sentient, although I think there are many, many reasons, some instrumental and some intrinsic, for treating plants and the world of nature well. But my book is about justice.


AM: Thanks, Martha. We’re going to turn now to questions from our audience. The first asks, can you give us the top three capabilities that relate to humans that may apply as well to most animals at this stage of our consciousness?


MN: I’m ready to admit I’m wrong if I’m shown to be wrong. The first three on the list are life, bodily health, and bodily integrity. But then I would go on to include all the others: senses, imagination and thought, affiliation, practical reason, meaning to be able to make choices about how your life goes, play, relationships with other species and the world of nature, control over your material environment. I think all, actually, are pertinent to animal lives.


JBK: This next question asks, is it truly the overpopulation of humans? Or is it that the unnecessary excesses of production, consumerism, and commercialism can be scaled back, limited, and converted to spaces and practices that contribute to Earth and animal healing and regrowth? In other words, is it a particular form of civilization and its economy that’s really at stake?


MN: Well, I think both are in question. The oil rigs that are out there drilling, that is an incursion into the seas that I think we would be better off without. But the fact is, in the case I was talking about with the elephants in Africa, people are living in a very rudimentary subsistence level in these villages. There are just an awful lot of them, and the elephants are very few in number, but they do need to strip the bark off of trees. Whole organizations have grown up to mediate those conflicts. But one way they need to be mediated is to give women a chance to regulate their own fertility. It’s partly a gender dominance issue, because men don’t want to use contraception often, and the women would quite like them to do that.


AM: Could you elaborate on where you think justice for animals finishes and justice for non-sentient beings begin? Do insects deserve justice? What about ecosystems? Bacteria? Related to that is a question asking whether you would extend the capabilities approach to the ethics of AI. If not, what is the key difference between animals and AI according to your model?


MN: According to the way that I understand justice, it pertains only to beings who are sentient, because it’s about the wrongful thwarting of a certain kind of striving, which requires perception to get you going towards the object of desire: the things that Aristotle talks about in the De Motu Animalium. Now, insects do many things in the world. But according to me, and according to current scientific research, they’re not subject to the theory of justice, because they’re not striving creatures. The world doesn’t look like anything in particular to them. They don’t have goals and so on. Now, that doesn’t mean we don’t have any duties to insects. It’s just justice that we’re talking about. And the same is true of plants. Now, what kind of ethical duties might we have? Insects are very important, first of all, instrumentally in the lives of sentient beings. So there’s that whole set of duties that we might have to preserve insect population. But also, they may have intrinsic interest and worth. That’s just not the part of ethics that I’m writing about. I’m writing about justice. Somebody else can defend the intrinsic importance of insect life and plant life, and I’d be very glad for them to do that. Now, AI is tricky. I don’t know anything, in truth, about AI, and I really have never studied it, and I do know that that’s a really complicated issue. I guess the question would be whether robots, for example, can be sentient. And I guess that’s a big question in that literature, too, to how we think about sentience in that connection. I would just wait to hear from people who know a lot more than I do about AI to see how they think about that issue.


JBK: A number of people are interested in the ethics of eating: not just humans eating other animals, but animals eating other animals. One question is, what if the characteristic form of flourishing as a species includes the hunting and devouring of other species? It seems plausible that hunting species experience powerful fulfillment through a hunt successfully executed. Does justice require enabling such opportunities? The question with humans has to do with your stance on veganism. What’s your stance on eating meat?


MN: On veganism, I do not think that the arguments for not using any form of animal product are good arguments. For example, wool. Sheep that are not regularly shorn, as they’ve now evolved to be, suffer from having their heavy coat dragging them down. I agree with Sue Donaldson and Will Kymlicka that there are forms of use that are perfectly okay. I agree with them, too, that eggs may be okay if they’re totally cage-free, and if we make sure that the animal still has options to reproduce. The dairy industry is much more difficult. Kymlicka and Donaldson say there’s no way to reform it to make it ethically adequate because the calf has to be taken from its mother. In any case, I agree with vegans in some respects, but not in all.

In terms of eating, we have to ask that old philosophical question: When is death a harm? And is it a harm? And for whom? That’s an issue that goes way back to Epicurus, who said that death isn’t a harm because we’re not there after we die. The termination, if it’s painless, is not itself a harm. I find fault with that argument: what’s wrong with death, I say, is the interruption of activities that you value. If they’re cut short in midstream, that harms the shape of your life, ex post. I do think death can be a harm for a being who’s got valuable projects underway. I do think that includes most animals, certainly until they get very old and decrepit. Most of the animals who are eaten are either very young, like lambs and calves—which is always totally unacceptable—or are in their prime. If they are animals that have a sense of time and have projects evolving through time, that’s a harm to that animal.

What would a world be like in which tragic dilemmas between humans and animals don’t arise anymore?

I do right now believe that it’s different for fish. Utilitarians, from Bentham to Jeff McMahan, have said that animals live in the moment. They don’t have these projects evolving through time. I think they’re wrong about most animals, but I do think that they’re right about fish. I think that’s how fish think. And therefore, the painless death of a fish—and I really mean painless: not line fishing, but conking with a mallet, for example—who’s had plenty of time to swim around in the wild and must have had a pretty decent life overall is not a harm to the fish, I believe. So I actually do eat fish. And I am less troubled about that than needing seventy grams of protein a day to stay healthy with my age and my exercise level. I feel happier about that than I feel about any dairy product that I might use. It’s something I wonder about, and I don’t feel happy about it, and I want us to learn more, but that’s where I am right now.

Now, about the first question. McMahan wrote an op-ed floating the question of whether we should eliminate, by gradual outbreeding, predatory species because of the harm that they do. Now, of course, that has drastic implications for the ecosystem. That’s one problem. But also, these animals are not doing anything wrong. They’re not deliberately inflicting harm. When humans kill other humans, we should expect them not to do that. With most predatory animals, that’s not the case. There’s another proposal made by some neo-Aristotelians that says, “Well, this is what they’re put there for. Just as the tiger’s there to kill a gazelle, so the gazelle’s purpose—its telos—is to be eaten by the tiger.” No! That’s just bogus Aristotelianism. Each species, we know, evolves to live, not to die. And they’re there because they were capable of surviving, and in this case, they’re being harmed and eaten up by a predator. I think we have to face up to the fact that they’re being harmed. But what can we do about those harms? In companion animal life, I think we do try to do something about it. Most companions of cats do not let their cats kill little birds, either by keeping them indoors, or if they’re outside, by taking them away from that activity. But they recognize that this is an innate instinct, so they give the cat a substitute activity: playing with a ball, playing with a scratching post, and all the things that good cat companions do.

Can we do that with other species in the wild? I think we just know too little to even venture in this direction. I suggest in the book that at least we can say to people, “Don’t make money out of exploiting this desire to see blood and gore.” People love to shell out a lot of money to go to Botswana and watch wild dogs jump on a little gazelle and tear it limb from limb before it’s even dead. Horrible death. When I went on a safari, four of the six people in my Jeep were there for that reason. But it’s really bloodlust, like the Roman gladiatorial games. I think we should stop what I call “sado-tourism.” That will at least show a recognition that the lives of these antelopes make a difference. Beyond that, I think we have to be hands-off until we know a lot more.


AM: Could you clarify what you mean in saying that negligence is a crime?


MN: Negligence is illegal. Obviously, you can be sued for negligence, and there are legally established criteria for saying that you have been wrongfully negligent. Now, there are some times when it actually comes into the criminal law. Different nations divide between civil law and criminal law in different ways. Reckless endangerment can be a criminal offense, even though it’s not deliberate. But anyway, the point is that I’m talking about both negligence and malice.


AM: Many people will be with us as we talk about companion and wild animals. They may even join us in condemning factory farming. Yet they’ll remain desperate to find some justification for continuing animal agriculture, even while claiming to respect and care for its victims. How can we break through those powerful social norms and push towards ending all needless exploitation, harming, and killing of sentient beings?


MN: I am an incrementalist. I think the best course is to end the worst abuses first. If we were left with only humanely raised pigs and chickens, that would still be bad, but it would be a lot better than the factory farming industry. And right now, politically, the factory farming industry has a lock grip on our whole political process through the money that’s bottled up there. You can’t pass any law that doesn’t have an exemption for the factory farming industry. We have these ag-gag laws that effectively forbid people to divulge the conditions in the factory farming industry. Those have been challenged in every state where they exist, but they haven’t been repealed yet or declared unconstitutional in all the states. So we need to fight on that first front and get this horrendous industry out of our political lives.

A full development of our humanity requires developing our capacities to care for the world of nature and for the animals in it.

But the larger issue is about how livelihoods can be changed. Every time we make an ethical improvement in some area of our lives, there are people who are put out of work. In Britain, when they ended fox hunting, the big complaint was, all the people who work in that industry, what are they going to do? Right now, a lot of whales are killed by lobster fishing lines that are used to hold the lobster pot as it goes down into the floor of the ocean: these lines get wrapped around the whale’s body, and slash it, and cause a terribly painful death. The debate around that is about how these fishermen are going to live. Well, you have to think about that. But I think there are Hegelian solutions which are, “There’s a new form of lobster line that doesn’t cause that problem,” and so forth. We need to think how these people are going to live. Maybe in the same industry, but maybe in a different industry. A lot of the people who were employed in the tobacco industry have not totally died, but they found other jobs in other industries, and that’s the way the economy works. In thinking about the ending of humane farming, we would then really have to take care for the people who work in that industry and finding them employment, absolutely.

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