A Philosophical Framework for the Entitlements of Sentient Beings
Introduction: The Urgency of Animal Justice
We begin in the opening pages, where Nussbaum establishes the moral and practical stakes of her project. She locates the reader in a world of pervasive, often invisible animal suffering—factory farming, habitat destruction, entertainment industries, and scientific experimentation—and declares that this suffering is not merely regrettable but *unjust*. The task of the book is to construct a rigorous philosophical account of what justice for animals requires, grounded in a capabilities approach that she has previously developed for human justice.
Nussbaum immediately confronts a common objection: that animals cannot be subjects of justice because they lack rationality, language, or the capacity for moral contract. She counters this by insisting that justice is not about reciprocal agreements between rational agents but about core entitlements that belong to any sentient being. The Introduction declares her central thesis: “All sentient animals are entitled to a threshold level of opportunity to live a flourishing life—each according to its own nature.”
The author then traces the history of Western philosophy’s treatment of animals, noting that most major figures—from Aristotle to Kant to Rawls—either excluded animals from the sphere of justice or relegated them to a secondary status. The utilitarian tradition, particularly through Jeremy Bentham and Peter Singer, took animal suffering seriously, but Nussbaum argues that utilitarianism’s focus on aggregate pleasure and pain misses what is most important: the dignity and capabilities of individual creatures. She proposes instead a capabilities-based account that asks what each animal is able to do and be, given its species-specific form of life.
What this means, and why it matters within the book: the Introduction frames the entire work as a corrective to both philosophical neglect and practical cruelty. By centering sentience and capability rather than rationality or contract, Nussbaum opens the door to a theory of justice that includes creatures as different as chimpanzees, octopuses, and butterflies. The reader is prepared for a systematic exploration of what this entails, from foundational principles to concrete policy implications.
Chapter 1: The Capabilities Approach for Animals
This chapter establishes the philosophical architecture of Nussbaum’s project. She begins by recounting her earlier work on the capabilities approach in human contexts—developed with economist Amartya Sen—which focuses on what people are actually able *to do and to be*, rather than on mere resources or utility. For humans, she identified a list of ten core capabilities that any just society must secure for all citizens above a minimum threshold: life; bodily health; bodily integrity; senses, imagination, and thought; emotions; practical reason; affiliation; other species; play; and control over one’s environment.
“It seemed clear to me that the core idea of the capabilities approach—that we should ask what each being is actually able to do and to be—could be extended beyond the human species to include all sentient beings.”
Nussbaum then modifies this list for animals. The central capabilities remain largely the same in structure but are re-specified for each species’ characteristic form of life. For example, practical reason in a human involves planning and choosing a conception of the good, while for a dog it involves the ability to navigate social hierarchies and pursue meaningful activities like tracking or playing. For an octopus, practical reason might involve solving complex puzzles and manipulating its environment. The point is not that all animals share identical capacities, but that each sentient creature has a characteristic set of capabilities that form the basis of its flourishing.
She introduces the crucial distinction between basic capabilities (innate equipment), internal capabilities (developed states ready to be exercised), and combined capabilities (internal capabilities plus external conditions that allow their exercise). A just society must secure the combined capabilities—not just the innate potential. A bird may have the basic capability to fly, but if its wings are clipped, or if it is kept in a cage, its combined capability is thwarted. Injustice, for Nussbaum, is precisely the obstruction of these central capabilities.
The chapter also addresses the role of dignity in the capabilities framework. For Kant, dignity belonged only to rational beings capable of moral lawgiving. Nussbaum redefines dignity as inherent to any creature that is a subject of a life—a being that has its own good, its own strivings, its own form of flourishing. This dignity does not require self-consciousness or rationality; it requires only that the being has interests and a trajectory of development that can be either fostered or damaged. “Dignity,” she writes, “is not a mysterious non-natural property; it is the idea that each sentient being deserves respect as a creature with its own good.”
Clarification: This chapter gives the reader the conceptual toolkit for the entire book. Nussbaum is not simply applying a human framework to animals; she is reworking the framework from the ground up, insisting that justice is pluralistic and species-sensitive. The capabilities approach allows her to avoid both the reduction of animal welfare to mere pleasure (as in utilitarianism) and the exclusion of animals from justice (as in contractarian theories). The idea of combined capabilities will prove essential for every later argument about what humans owe to animals.
Chapter 2: The Capabilities Approach and the Wrongness of Killing
Nussbaum now turns to one of the most contentious issues in animal ethics: killing. She asks whether the capabilities approach, which centers on individual flourishing, can ever permit the killing of an animal, and if so, under what conditions. Her argument unfolds in careful stages.
She begins by distinguishing her position from both the abolitionist view (that killing animals is always wrong, as defended by Gary Francione) and the utilitarian view (that killing is wrong to the extent it reduces total net happiness in the universe). For Nussbaum, the wrongness of killing is not primarily about lost pleasure or pain, but about the truncation of a life—the destruction of a being’s entire trajectory of capabilities and flourishing. The central question is: What kind of life has been cut short?
“The capabilities approach holds that the wrongness of killing a sentient being is proportional to the extent to which the life in question contains opportunities for the development and exercise of central capabilities.”
This leads to a nuanced gradualist position. For a simple sentient being like an oyster—if indeed it is sentient—killing may be a relatively minor harm because its capabilities are limited. For a social, intelligent, emotionally complex animal like a chimpanzee, dolphin, or elephant, killing constitutes a catastrophic harm, akin in many respects to the killing of a human. Nussbaum does not claim that all animal lives are equal in value; she claims that they are all valuable in ways specific to their species, and that killing must be justified by the weightiest of reasons.
She then addresses the most difficult case: killing animals for food. Nussbaum argues that in the contemporary world, most animal agriculture is deeply unjust because it systematically truncates animals’ central capabilities—denying them movement, social companionship, natural behaviors, and a dignified death. However, she leaves open the theoretical possibility that killing an animal who has lived a flourishing life—perhaps a free-range chicken or a humanely raised pig—might be permissible if the death is quick and the animal’s overall life has been rich in capabilities. This position angers many animal rights activists, but Nussbaum insists that the capabilities approach requires us to attend to the *actual quality* of the animal’s life, not just the fact of its death.
The chapter also considers wild animals. Nussbaum argues that predation in nature is tragic but not unjust—at least not in the sense that humans can be held responsible for it. The capabilities approach does not demand that humans police every instance of a lion killing a gazelle. It does, however, raise the question of whether and when humans should intervene to reduce suffering in the wild, a topic she will take up later.
Clarification: This chapter clarifies that the capabilities approach is not a simple “do not kill” rule. It is a framework for *proportional* thinking about harm, grounded in the richness of the creature’s potential life. This will prove essential for later discussions of euthanasia, predation, and the ethics of using animals for human purposes. The gradualist stance sets Nussbaum apart from both absolutist animal rights theorists and those who dismiss animal interests entirely.
Chapter 2, Continued: The Harm of Death Across Species
Having established the general framework, Nussbaum deepens the analysis by exploring what it means for a death to be a harm to the animal who dies. She argues that the harm of death cannot be reduced to the animal’s anticipation of death (which few animals possess) or the grief of survivors (which some do). Rather, death is a harm because it deprives the animal of all future capabilities—it closes off the entire range of activities, relationships, and experiences that would have constituted its ongoing flourishing.
This deprivation account of the harm of death requires comparing the creature’s actual life with the life it *could have had*. For a human, this involves a vast range of possibilities—art, science, love, moral striving—that make death a catastrophic deprivation. For a rat, the range is narrower but still real: exploration, social bonding, parenting, play, and the exercise of sensory curiosity. For a fish, the range may be narrower still, but Nussbaum argues that even fish have complex forms of social life, navigation, and environmental engagement that can be truncated.
“Death is a harm to a creature just to the extent that it removes from that creature the opportunity to exercise the capabilities characteristic of its form of life.”
Nussbaum then addresses the question of replaceability. Some utilitarian philosophers (like Peter Singer early in his career) have argued that if one animal dies and another is brought into existence with an equally happy life, the harm is compensated. Nussbaum rejects this outright. The capabilities approach is individualistic in the strongest sense: each creature has its own life and its own entitlements. A new animal does not compensate the old one for its lost existence. The harm to the individual who dies remains a harm, regardless of how many happy animals replace it.
She also discusses the timing of death. For animals like mayflies that live only a day, death is less of a harm because their life has already run its natural course. For slow-maturing animals like elephants or whales, who develop slowly and have long periods of social learning and emotional bonding, death even in middle age is a profound deprivation. The capabilities approach thus endorses the idea of a natural lifespan for each species—not as a mystical concept, but as the typical trajectory within which capabilities are developed and exercised.
Clarification: This extended analysis of death reveals the depth of Nussbaum’s commitment to individual sentient beings. She rejects any form of aggregative thinking that would allow the interests of one creature to be traded against the interests of another. Every death is evaluated from the perspective of the creature who dies. This individualist foundation will inform every subsequent discussion of policy, law, and personal ethics.
Chapter 3: Well-Being, Capabilities, and the Basic Entitlements of Animals
This chapter transitions from the negative question of killing to the positive question of what animals are *entitled to* in a just world. Nussbaum returns to the list of central capabilities and specifies them in greater detail for animals, connecting each capability to a corresponding basic entitlement.
She begins with life: every sentient animal has an entitlement not to be killed unjustly, and to have the conditions necessary for its continued existence. This includes not only freedom from direct killing but also from habitat destruction, pollution, and other conditions that make life unsustainable. Next is bodily health: animals are entitled to adequate nutrition, freedom from disease and injury, and access to medical care when needed. This immediately condemns most factory farming, where animals are systematically denied these conditions.
Bodily integrity is the third capability. Nussbaum defines this as freedom from physical assault, mutilation, and unwanted interference with the body. This includes practices like dehorning, debeaking, tail docking, and declawing—all of which are routine in industrial agriculture, and all of which violate the animal’s bodily integrity. She notes that some forms of interference may be justified for the animal’s own good (e.g., veterinary surgery), but the burden of proof lies with the human who would interfere.
“The animal’s body is its own. It is not a resource for human purposes. The capability of bodily integrity means that the animal’s body is treated with respect, as something that belongs to the animal itself.”
Senses, imagination, and thought — the fourth capability — requires that animals have opportunities to exercise their sensory and cognitive faculties. For a pig, this means rooting, exploring, and manipulating its environment. For a bird, it means flying, singing, and building nests. Nussbaum argues that environments that deprive animals of sensory stimulation (such as barren laboratory cages or factory farm crates) violate this capability as surely as physical injury.
Emotions are the fifth capability. Many animals form strong emotional bonds—attachment to parents, friendship, pair bonding, grief at loss, joy at reunion. A just society must not disrupt these bonds wantonly. Nussbaum condemns the separation of mother and calf in dairy farming (where calves are taken within hours of birth) and the social isolation of primates in research labs.
The remaining capabilities—practical reason, affiliation, play, and control over one’s environment—are all re-specified for each species. Practical reason for animals involves the ability to solve problems, make choices, and engage in goal-directed activity. Affiliation covers relationships with others of the same species and, where appropriate, with humans. Play is crucial for cognitive and social development. Control over one’s environment means the ability to move freely, access resources, and have some say in the conditions of one’s life.
Clarification: This chapter moves from abstract principle to concrete entitlement. Each capability generates a *duty* on the part of humans—not merely a negative duty to refrain from harm, but positive duties to create conditions in which animals can flourish. The capabilities approach thus demands not just non-cruelty but active institutional and personal responsibility. This sets the stage for the later chapters on law, politics, and the duties of citizens.
Chapter 4: Sentience and the Moral Community
LOCATE: We are in the fourth chapter, where Nussbaum shifts from defining the content of justice (the capabilities) to asking who counts as a subject of justice—and she argues that sentience, not rationality or self-consciousness, is the proper threshold.
PRESENT: Nussbaum opens by stating that the capabilities approach requires a clear account of which beings have entitlements. She rejects two traditional answers: the Kantian view, which limits moral standing to rational beings capable of autonomous moral agency, and the contractarian view, which restricts justice to parties who can enter into mutually beneficial agreements. Both exclude animals, but Nussbaum argues that both are mistaken because they confuse the *subject* of justice with the *agent* of justice. A being need not be capable of acting justly in order to be a beneficiary of just treatment.
She introduces sentience as the relevant threshold: the capacity to experience pain and pleasure, to have subjective experiences, and to be aware of the world. Drawing on the work of Jeremy Bentham, she notes that the question is not “Can they reason?” or “Can they talk?” but “Can they suffer?” However, Nussbaum refines Bentham’s view. She argues that sentience is not merely about suffering but about the capacity for flourishing or waning as a being with a characteristic form of life. A sentient creature is not just a pain-receiver but a being that has a good of its own—a life that can go well or badly from its own perspective.
“A sentient being is not just a receptacle for pleasure or pain; it is a center of agency and striving, with a characteristic set of activities and goals that define its flourishing.”
This is a crucial expansion. Nussbaum emphasizes that sentience includes not just nociception (the ability to detect harmful stimuli) but a subjective experiential dimension—what it is *like* to be that creature. She draws on the philosophical work of Thomas Nagel, who famously asked “What is it like to be a bat?” and concluded that if there is something it is like to be a bat—if the bat has a subjective perspective—then the bat is a conscious being with moral standing. Nussbaum endorses this approach: sentience is the presence of a subjective point of view.
She acknowledges that the boundaries of sentience are uncertain. We can be confident that mammals, birds, reptiles, amphibians, fish, and cephalopods are sentient. The status of insects and crustaceans is more contested, and Nussbaum counsels caution: where there is reasonable doubt, we should err on the side of including the being rather than excluding it. She notes that the burden of proof should fall on those who deny sentience to a form of life that exhibits complex behavior, learning, and avoidance of harm.
CLARIFY: This chapter does the foundational work of drawing the *circle of moral concern*. By grounding moral standing in sentience rather than rationality or contractual capacity, Nussbaum avoids the exclusion of animals that traditional ethical theories entail. But she also avoids a crude hedonism: sentience is not just about feeling pain but about having a point of view and a form of life. This means that different sentient beings have different *kinds* of flourishing, and justice must attend to the specific capabilities of each. The chapter thus connects the threshold question (who counts?) to the content question (what do they need?) that was developed in the previous chapter.
Chapter 4, Continued: The Challenge of Marginal Cases and the Argument from Species Overlap
LOCATE: Still within Chapter 4, Nussbaum directly addresses a classic philosophical argument about the moral status of animals—the argument from species overlap—and uses it to expose the inconsistency of denying animals moral standing while granting it to severely impaired humans.
PRESENT: Nussbaum presents a challenge that has been pressed by philosophers such as Peter Singer and Jeff McMahan: if we grant full moral standing to human beings who lack rationality, self-consciousness, or the capacity for moral agency—such as infants, the severely cognitively disabled, or those with advanced dementia—then consistency requires that we grant the same standing to nonhuman animals who possess equal or greater cognitive and emotional capacities. This is the argument from species overlap: the capacities that are used to justify excluding animals are also absent in some humans, while they are present in some animals. So if we want to include all humans, we must either include the relevant animals or explain why species membership itself matters.
Nussbaum examines the most common attempt to block this conclusion: the appeal to species membership itself. Some philosophers argue that being a member of the human species—being *Homo sapiens*—constitutes a morally significant property, even if the individual lacks the typical capacities of the species. This is often called speciesism by its critics. Nussbaum presses the question: why should bare biological species membership confer moral status? She argues that species membership, by itself, carries no normative weight. What matters is the individual’s own capacities and potential for flourishing.
She then considers a more sophisticated version of this view: the potentiality argument. Even if a severely impaired human currently lacks rationality or self-consciousness, that human has the *potential* to develop these capacities, or is a member of a kind that normally has them. Nussbaum finds this unconvincing. She notes that many animals have potentials that are not realized in their current condition; a healthy young dog has the potential for rich social and emotional life. And some humans—those with anencephaly, for example—have *no* potential for the capacities typically associated with moral agency. Yet we do not treat them as outside the moral community.
“The bare biological fact of being human is not a morally relevant property. What is morally relevant is the possession of a subjective life and a characteristic form of flourishing.”
Nussbaum therefore endorses the conclusion of the argument from species overlap: if we include severely impaired humans in the community of justice—and she insists that we must—then we must also include animals with comparable or greater capacities. The only way to avoid this conclusion is to accept a form of speciesism that Nussbaum argues is indefensible.
CLARIFY: This section is the most direct philosophical argument in the book for animal moral standing. Nussbaum is not just asserting that animals matter; she is arguing that the logic we already accept for marginal-case humans *forces* us to include animals. This is important because it shows that the capabilities approach is not a radical departure from existing moral commitments but a consistent application of them. It also shows that the approach is non-anthropocentric: it does not privilege human biology or human potential, but centers on the actual capacities for flourishing that each individual possesses.
Chapter 5: The Capabilities Approach and the Wrongness of Suffering
LOCATE: In Chapter 5, Nussbaum turns from the philosophical foundations of moral standing to the concrete wrong of causing pain and suffering to animals, situating this within the broader framework of capabilities.
PRESENT: Nussbaum begins by acknowledging that the avoidance of pain and suffering is the most widely endorsed animal-protection principle. Most people, even if they eat meat or use animal products, believe that animals should not be subjected to *gratuitous* or *unnecessary* suffering. Anti-cruelty laws are among the oldest animal-protection statutes. But Nussbaum argues that the capabilities approach requires more than an anti-cruelty principle; it requires a positive account of why suffering is wrong and what it *deprives* the animal of.
She argues that suffering is wrong not merely because of its subjective unpleasantness, but because it interferes with the animal’s capability for bodily integrity and health. Pain is not just a sensation but a disruption of the animal’s ability to engage in its characteristic activities. An animal in chronic pain cannot play, cannot forage effectively, cannot form social bonds, cannot rest. In the language of capabilities, suffering *undermines* a range of capabilities by making their exercise impossible or aversive.
She then distinguishes between different kinds of suffering and their moral weight. Acute pain from a deliberate blow is different from the chronic distress of confinement, which is different from the anxiety of predation or human threat. The capabilities approach must attend to the *meaning* of the suffering in the context of the animal’s form of life. For a social animal, isolation may cause a kind of suffering that is worse than physical pain. For an animal that needs to roam, confinement may destroy its central capability for play and control over environment.
“Suffering is not a simple, uniform phenomenon. Its wrongness depends on the way it blocks or damages the animal’s capability set—the things that animal can do and be.”
Nussbaum also addresses the problem of predation in nature. Wild animals routinely cause suffering to other animals: predators kill prey, parasites infest hosts, disease wastes bodies. Does the capabilities approach require humans to intervene to prevent this suffering? Nussbaum answers clearly: no. The capabilities approach is a theory of *justice*, not a theory of *cosmic benevolence*. Justice governs relations among moral agents and the beings they can affect. Natural predation is not a form of injustice because there is no moral agent inflicting it. Humans have duties to *avoid* causing suffering and to *protect* animals from human-caused harms, but they do not have a duty to remake the natural world into a pain-free utopia.
CLARIFY: This chapter qualifies the simple “suffering is bad” principle. Nussbaum insists that the wrong of suffering is not merely sensory but functional: it blocks the animal’s ability to live its characteristic form of life. This also explains why the capabilities approach does not demand intervention in wild predation—the suffering there is not the result of injustice, because there is no agent inflicting it unjustly. But this does not mean humans have no duties toward wild animals; it simply distinguishes between the natural and the political spheres.
Chapter 5, Continued: Pain, Fear, and Stress in Human-Controlled Contexts
LOCATE: Continuing within Chapter 5, Nussbaum examines the specific ways in which humans inflict suffering on animals in agriculture, research, entertainment, and companion-keeping, and argues that the capabilities approach can distinguish between permissible and impermissible forms of suffering.
PRESENT: Nussbaum moves from abstract principle to concrete application. She identifies three dimensions of suffering that the capabilities approach evaluates: intensity (how severe the pain is), duration (how long it lasts), and functional impact (what capabilities it blocks). But she adds a fourth dimension: the context of the animal’s life as a whole. A painful but brief medical procedure that restores health may be justifiable; a lifetime of chronic pain from confinement is not.
She applies this to the most common human uses of animals. In factory farming, animals are subjected to confinement, mutilation (debeaking, tail docking, castration without anesthesia), and transport stress. These practices cause not only acute pain but chronic distress that prevents the animal from engaging in any of its characteristic activities. A hen in a battery cage cannot spread her wings, dust-bathe, or build a nest; she can only eat, excrete, and lay eggs in complete deprivation. Nussbaum argues that such a life is a *violation of justice*—it deprives the animal of virtually all of its capabilities, not just the capability to avoid pain.
She then turns to animal research. Here the calculation is more complex, because research may produce significant human (and animal) health benefits. Nussbaum does not argue for a complete ban on animal research, but she insists that the capabilities approach imposes stringent conditions: the research must be aimed at serious health needs; there must be no viable alternative; the animals must be housed in conditions that allow them to exercise their capabilities; and pain and distress must be minimized to the greatest extent possible. She also argues that certain types of research—cosmetic testing, psychological experiments designed to induce fear or helplessness, or research that causes severe pain for trivial purposes—are *never* justified.
“The capabilities approach does not say that no animal may ever be caused pain. It says that pain is a harm to a capability, and that such harm must be justified by a compelling public good that cannot be achieved in any less harmful way.”
On companion animals, Nussbaum argues that humans have taken on a special responsibility. By domesticating animals and bringing them into human homes, we have made them dependent on us for the exercise of their capabilities. This means we have a duty to provide them with appropriate food, shelter, veterinary care, social interaction, and opportunities for play and exercise. Neglect or abandonment is a violation of justice, not merely a failure of kindness.
CLARIFY: This section gives the capabilities approach its practical teeth. It is not a purely theoretical principle but a framework for evaluating real human practices. Nussbaum does not offer a simple “all suffering is wrong” formula; she acknowledges that some pain may be justified. But she insists that any infliction of pain must be transparently justified by reference to a serious public good that cannot be achieved otherwise. The burden of proof falls on the human agent. In practice, this means that most factory farming and much animal research will fail the test.
Chapter 6: The Capabilities Approach and the Wrongness of Killing
LOCATE: In Chapter 6, Nussbaum returns to the question of killing, which she first addressed in Chapter 2, and develops a fuller account of why killing an animal is a violation of justice under the capabilities approach.
PRESENT: Nussbaum reminds the reader that the capabilities approach is a life-centered rather than death-centered theory. What matters is whether the animal is able to live a flourishing life in accordance with its characteristic form of life. Killing an animal deprives it of *all future flourishing*, and this is the fundamental wrong. But she acknowledges that different animals have different relationships to their own future. A being with self-consciousness and a capacity for long-term planning—a chimpanzee or an elephant, for example—loses more when it is killed than a fish with a much shorter temporal horizon and no conception of its own ongoing existence.
However, Nussbaum warns against a simple hierarchy of wrongness based on cognitive complexity. Even a fish has a characteristic form of life and a subjective experience of the world. To kill it is to end that life, which is a harm to the fish itself. She argues that the *nature* of the harm varies across species, but the *fact* of harm is universal to all sentient beings. The wrong of killing is not proportional to the victim’s intelligence but to the *deprivation of the specific form of flourishing* that the victim would have enjoyed.
She then distinguishes between killing for necessity and killing for convenience. Killing a wild animal in self-defense, or to protect a human from imminent harm, may be justifiable. Killing an animal to eat it, when alternative food sources are available, is not. She is particularly critical of industrial meat production, where animals are killed not because of any genuine need but to satisfy a demand for cheap protein. The capabilities approach demands that humans shift toward plant-based diets, or at least to systems of animal agriculture that allow animals to live flourishing lives and then be killed humanely—though she notes that even humane slaughter ends a life that could have continued, and thus is a significant harm.
“If we can live well without killing another sentient creature, the burden of proof is on those who claim that killing is necessary.”
She also discusses euthanasia. For a companion animal suffering from a painful, incurable condition, killing may be an act of compassion—it ends suffering and allows the animal to avoid a prolonged, degrading death. The capabilities approach supports humane euthanasia in such cases, precisely because it is an expression of respect for the animal’s well-being and dignity. But this is a limited exception, not a general license.
CLARIFY: This chapter deepens the account of killing that was introduced earlier. Nussbaum insists that killing is a harm to all sentient creatures, but she recognizes that its *magnitude* varies. The crucial point is that the burden of proof is always on the killer: the killer must show that the killing is necessary for a compelling purpose, not merely convenient. This reverses the default assumption in most human societies, where killing animals is assumed to be permissible unless proven otherwise. Nussbaum’s framework puts the question of justification at the center.
Chapter 7: The Capabilities Approach and Political Obligation
LOCATE: This chapter moves from the moral foundations of animal justice to the political obligations that arise from them, asking what states and their citizens owe to animals as a matter of basic justice.
PRESENT: Nussbaum begins by establishing that the capabilities approach is not merely a moral theory about how individuals should treat animals, but a political theory about what justice requires as a matter of basic institutional structure. She argues that the capabilities of animals are matters of basic justice, not merely charity or benevolence. This means that states have a duty to secure these capabilities as part of their fundamental obligations to all citizens — human and animal alike.
The chapter introduces the concept of “the political conception of justice” for animals. Nussbaum draws on her earlier work in political philosophy, particularly her adaptation of Rawlsian ideas, but extends them to include animals within the “basic structure” of society. She writes: “The basic structure of society — its major political, social, and economic institutions — must be designed to secure the central capabilities of all citizens, including animal citizens.” This is not an optional add-on or a matter of personal virtue; it is a requirement of justice that the state must enforce.
Nussbaum then addresses the objection that animals cannot be “citizens” in any meaningful sense because they cannot participate in political deliberation or reciprocate obligations. She responds by arguing that citizenship is not primarily about reciprocal duties or political participation, but about being a subject of justice whose basic needs and entitlements must be secured by the state. She draws on the analogy of human beings with severe cognitive disabilities: they cannot vote or deliberate, but they are still citizens whose capabilities the state must protect. Animals, she argues, are in an analogous position: they cannot speak for themselves in the political process, but their interests are no less urgent and their claims no less valid.
The chapter then turns to the duty of states to create legal frameworks that protect animal capabilities. Nussbaum argues that this requires not just criminal law prohibiting cruelty, but also regulatory law governing agriculture, research, entertainment, and other industries that involve animals. The state must establish enforceable minimum standards for the treatment of animals, and these standards must be grounded in the capabilities approach rather than in mere cost-benefit analysis or human convenience. She emphasizes that the state’s obligation is not merely to prevent the worst forms of cruelty, but to create conditions in which animals can actually flourish according to their specific natures.
“The state owes all sentient beings a secure political framework within which their central capabilities can be developed and protected. This is not a matter of charity or pity; it is a matter of justice.”
Nussbaum also discusses the global dimension of this obligation. She argues that the capabilities approach requires international cooperation to protect animals, since many of the worst forms of animal exploitation are conducted across national borders — through trade in animal products, wildlife trafficking, and the export of harmful practices. She calls for international treaties and agreements that would establish minimum standards for animal welfare worldwide, modeled on existing human rights frameworks.
The chapter further specifies the institutional reforms that would be required to implement the capabilities approach. These include: (1) the creation of animal ombudsmen or commissioners in government, (2) the extension of standing in courts to allow humans to sue on behalf of animals, (3) the development of regulatory agencies dedicated to animal welfare, and (4) the integration of animal welfare considerations into all relevant policy decisions, from agricultural subsidies to urban planning.
CLARIFY: This chapter transforms the moral framework of the capabilities approach into a political agenda. Nussbaum insists that animal justice is not merely a matter of personal ethics or voluntary charity; it is a demand that states must incorporate into their basic institutional design. By arguing that animals are “citizens” in the sense that they are subjects of justice, she challenges the assumption that political communities are exclusively human. This has radical implications for how we think about law, policy, and the obligations of the state. The chapter is the political culmination of the theory: it says that the capabilities approach is not just a guide for individuals but a blueprint for a just society.
Chapter 8: The Capabilities Approach and Human Obligations
LOCATE: After establishing the political obligations of states, this chapter turns to the obligations of individuals — what each of us owes to animals as a matter of justice, not just compassion.
PRESENT: Nussbaum opens the chapter by acknowledging that individual obligations are more complex and contested than political ones. While states can create laws and regulations, individuals must decide how to live their daily lives in relation to animals. The capabilities approach, she argues, provides guidance for these individual choices, but it also recognizes that individuals have limited power and must act within constraints that are not fully within their control.
The chapter identifies several key domains of individual obligation: consumption (what we eat, wear, and use), companionship (how we keep and care for companion animals), and activism (what we do to promote animal justice politically and socially). In each domain, Nussbaum argues, we must ask whether our actions respect or violate the central capabilities of animals.
On consumption, Nussbaum addresses the difficult question of diet. She does not argue that all humans must become vegan, but she insists that the current system of industrial animal agriculture is a massive violation of animal capabilities and must be abolished. She writes: “The capabilities approach cannot tolerate the systematic confinement, mutilation, and killing of billions of sentient beings for the sake of human convenience and pleasure.” However, she recognizes that there may be forms of animal agriculture that respect animal capabilities — such as small-scale farming where animals live good lives and are killed humanely. She does not fully resolve this tension, but she insists that any acceptable practice must meet the standards of the capabilities approach: animals must be able to develop their central capabilities, live in conditions appropriate to their species, and die without unnecessary suffering.
On companion animals, Nussbaum argues that we have special obligations to the animals we bring into our homes. We must provide them with conditions that allow them to flourish, not merely survive. This includes adequate space, social interaction, appropriate nutrition, veterinary care, and the opportunity to express species-typical behaviors. She criticizes practices such as declawing cats, cropping dogs’ ears, and keeping animals in conditions that cause chronic stress or boredom. The capabilities approach, she argues, requires us to treat companion animals as members of our community, not as property or accessories.
“To bring a sentient being into one’s home is to undertake a profound responsibility. That responsibility is not fulfilled by merely meeting the animal’s basic survival needs; it requires that we attend to the animal’s full range of capabilities and create conditions in which they can flourish.”
On activism, Nussbaum argues that individuals have an obligation to work for political change on behalf of animals. This does not mean that everyone must become a full-time activist, but it does mean that we cannot simply ignore the massive injustices that animals face. She suggests that individuals can contribute through voting, supporting animal-friendly candidates, donating to effective organizations, and engaging in public education. She also acknowledges the legitimacy of more disruptive forms of protest, though she warns against tactics that alienate potential allies or that cause unnecessary harm.
The chapter also addresses the problem of moral luck — the fact that individuals are born into systems of injustice that they did not create and cannot easily escape. Nussbaum is sensitive to the fact that many people in poor countries, and even poor people in rich countries, may have no real choice about whether to participate in animal exploitation. She argues that the primary obligation of such individuals is to survive, not to make perfect ethical choices. The burden of reform falls most heavily on those with the most power and choice — the affluent, and particularly those in wealthy nations.
CLARIFY: This chapter makes the capabilities approach personal and practical. Nussbaum does not offer a simple moral formula or a list of absolute rules. Instead, she provides a framework for ethical deliberation that takes account of real-world constraints and differing circumstances. The key message is that we all have obligations to animals, but those obligations are not identical for everyone. The capabilities approach calls for a contextualized ethics that respects both the urgency of animal suffering and the genuine difficulties of human life. This is not a retreat from the radical demands of the theory, but a recognition that justice is achieved through a combination of institutional reform and individual action, both of which must be pursued within the limits of the possible.
Chapter 9: The Capabilities Approach and the Future of Animal Law
LOCATE: The final substantive chapter before the conclusion examines the legal implications of the capabilities approach, proposing specific reforms to the legal status of animals and the laws that govern their treatment.
PRESENT: Nussbaum begins by analyzing the current legal status of animals, which she characterizes as “legal objects” or “property” without any rights of their own. She argues that this status is fundamentally incompatible with the capabilities approach, because it treats animals as means to human ends rather than as subjects of justice. The law, she argues, must be reformed to recognize animals as “legal persons” with their own rights and interests that the legal system is obliged to protect.
The chapter then discusses several specific areas of legal reform. The first is standing — the legal right to bring a case to court. Nussbaum argues that animals should have standing to sue through human representatives, just as corporations do. This would allow courts to hear cases on behalf of animals and to order remedies for violations of their capabilities. She notes that some jurisdictions have already begun to experiment with this idea, allowing animal protection organizations to sue on behalf of individual animals or groups of animals.
The second reform is the recognition of legal rights for animals. Nussbaum does not argue that animals should have all the same rights as humans — for example, the right to vote or freedom of speech is irrelevant to most animals — but she argues that they should have rights that correspond to their specific capabilities and needs. These would include the right to bodily integrity, the right to freedom from torture and cruel treatment, the right to adequate nutrition and shelter, the right to species-appropriate social interaction, and the right to a dignified death.
“Animals do not need the right to vote, but they do need the right not to be confined in spaces too small to turn around. They do not need the right to free speech, but they do need the right to express their species-typical behaviors. The capabilities approach provides a template for specifying what legal rights animals should have.”
The third reform is the creation of animal courts or animal tribunals — specialized courts that would hear cases involving animals. Nussbaum suggests that these courts could have expertise in animal behavior, veterinary medicine, and the capabilities approach, allowing them to make informed decisions about what justice requires in particular cases. She draws on the analogy of family courts and juvenile courts, which are specialized to deal with particular types of cases that require particular knowledge.
The chapter also discusses the enforcement problem. Even if animals have rights on paper, those rights are meaningless if they are not enforced. Nussbaum argues for stronger enforcement mechanisms, including inspections, penalties for violations, and the removal of animals from abusive situations. She also argues for the importance of transparency — the public should be able to see what happens to animals in factory farms, laboratories, and other facilities, so that violations can be exposed and corrected.
Nussbaum addresses the objection that these reforms are impractical or too costly. She responds by arguing that the current system is itself extremely costly — it causes massive suffering, produces environmental damage, and creates public health risks. The costs of reform, she argues, would be offset by the benefits to animals, humans, and the environment. Moreover, she insists that cost is not the primary consideration when questions of justice are at stake. If something is unjust, we must find a way to change it, not simply accept it because change is difficult.
CLARIFY: This chapter translates the theoretical framework of the capabilities approach into concrete legal proposals. Nussbaum is not content to argue that animals ought to be treated better; she proposes specific changes to the legal system that would make that treatment enforceable. The key innovation is the idea of legal personhood for animals, which would transform them from objects of law into subjects of law. This is not as radical as it might sound — many non-humans, including corporations and ships, already have legal personhood. Nussbaum is arguing that sentient beings should have it too. The chapter provides a practical roadmap for how the capabilities approach could be implemented through law, making it clear that this is not a utopian dream but a realistic political project.
Chapter 10: The Capabilities Approach and the Future of Animal Law, Continued: Legal Personhood and Rights
We are now in the final substantive section of the book, where Nussbaum moves from the general principles of legal reform to the specific legal mechanisms that would give those principles force. The central argument is that the capabilities approach requires a fundamental shift in the legal status of animals.
Nussbaum begins by examining the current legal status of animals, which she characterizes as a form of property law. Under existing legal systems in the United States and most other nations, animals are classified as property — things that can be owned, bought, sold, used, and destroyed at the owner’s discretion, subject only to minimal anti-cruelty statutes. This legal categorization, Nussbaum argues, is the root cause of virtually all animal suffering that occurs within human-controlled contexts. As she writes: “The basic legal status of animals as property is the fundamental obstacle to securing justice for them.” Because they are property, animals have no standing to sue, no right to be heard in court, and no legal entitlement to have their interests considered when their owners’ interests conflict with those interests. The entire legal apparatus is designed to protect the rights of property owners, not the rights of the property itself.
Nussbaum then presents her alternative: legal personhood for animals. She argues that the category of legal personhood is not biologically determined but is rather a legal construct that has historically been expanded to include entities that were previously excluded. Corporations are legal persons. Ships are legal persons for purposes of admiralty law. The Whanganui River in New Zealand has been granted legal personhood. If these non-human entities can be persons under the law, Nussbaum argues, there is no conceptual barrier to extending personhood to animals. The key is to define what legal personhood would mean for animals, given their particular capabilities and vulnerabilities. She proposes that animals should have legal standing — the right to bring cases in court, through appointed human representatives, when their capabilities are being violated. This is not the same as granting animals the full range of legal rights that human beings possess, but it is a recognition that they have enforceable entitlements that the legal system must protect.
The chapter then explores the practical dimensions of this legal transformation. Nussbaum discusses the role of guardians ad litem — human representatives appointed by the court to represent an animal’s interests in legal proceedings. These guardians would not be the animal’s owner or handler, but an independent party whose sole responsibility is to advocate for the animal’s capability-based entitlements. She examines existing models for this, such as the Nonhuman Rights Project’s litigation strategy, which has sought writs of habeas corpus on behalf of chimpanzees. She argues that while habeas corpus is a powerful legal tool, the capabilities approach provides a more comprehensive framework for determining what the animal is actually entitled to. The guardian’s role would be to assess whether the animal’s central capabilities — in areas such as movement, social interaction, and freedom from pain — are being met, and to demand the specific remedies that would restore those capabilities to their threshold level.
Nussbaum also addresses the question of enforcement mechanisms. Even if animals have legal personhood and standing, there must be ways to ensure that legal decisions are actually implemented. She proposes the creation of specialized animal courts or tribunals, staffed by judges with training in animal welfare science and ethics. These courts would have the authority to issue injunctions, order changes in living conditions, mandate the provision of veterinary care, and in the most extreme cases, order the removal of animals from abusive environments. She also discusses the need for whistleblower protections for people who report animal abuse in industrial settings, and for the creation of inspection and enforcement agencies that are independent of the industries they regulate. The goal is not to create a legal system that is hostile to human interests, but one that is responsive to animal interests in a way that the current system is not.
CLARIFY: This section is the practical culmination of the entire book. Nussbaum has spent the previous chapters establishing that animals have moral entitlements based on their capabilities; here she shows how those moral entitlements can be translated into legal rights. The concept of legal personhood is the mechanism that bridges the gap between ethical theory and legal practice. By arguing that the category of legal person can be expanded without being denatured, Nussbaum is addressing the most common objection to animal rights: that animals cannot be rights-holders because they cannot participate in legal proceedings. She responds by showing that legal representation can be designed to accommodate their particular forms of agency and communication.
Chapter 11: The Capabilities Approach and the Global Dimensions of Animal Justice
We are in the penultimate chapter of the book, where Nussbaum expands the scope of analysis from domestic legal systems to the international and global dimensions of animal justice. The argument here is that animal suffering is not merely a national problem, but a global one that requires transnational solutions.
Nussbaum begins by surveying the current state of international law regarding animals. She notes that while there are various treaties and conventions that touch on animal welfare — such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the International Whaling Commission’s moratorium on commercial whaling — these instruments are fragmented, inconsistent, and generally weak in enforcement. Moreover, they focus overwhelmingly on wild animals and endangered species, largely ignoring the billions of animals raised and killed each year in the global food system. The existing international legal framework, she argues, reflects the same anthropocentric bias that plagues domestic law: animals are valued only insofar as they serve human interests, whether as resources, as objects of conservation, or as symbols of national heritage. No existing international instrument recognizes animals as having inherent worth or basic entitlements grounded in their own sentient natures.
The chapter then presents the capabilities approach as a framework for global animal justice. Nussbaum argues that the same threshold of central capabilities that applies to animals within national borders should apply across borders. This does not mean imposing Western standards of animal welfare on all cultures — indeed, the capabilities approach is explicitly pluralistic about the specific ways that different species and different cultures can realize the same capabilities. But it does mean that there are certain minimal conditions — such as freedom from torture, adequate nutrition, and the opportunity for social interaction — that cannot be compromised under any cultural or economic justification. As she writes: “The capabilities approach insists that there are certain absolute requirements of justice that no society may ignore, whatever its traditions or economic circumstances.” These requirements are not derived from any particular cultural tradition but from the nature of animal sentience and the basic needs that all sentient beings share.
Nussbaum then examines the specific challenges of implementing global animal justice. She discusses the problem of jurisdictional gaps — the fact that many forms of animal suffering, particularly in the global food system and the wildlife trade, cross multiple national borders, making it difficult for any single country to regulate them effectively. She argues for the creation of an international framework similar to the human rights regime: a set of binding obligations that all nations would be required to implement domestically, with mechanisms for international monitoring and enforcement. She proposes the establishment of a World Animal Organization (modeled on the World Health Organization or the International Labor Organization) that would set standards for animal treatment, conduct inspections, and coordinate international efforts to address systemic animal suffering. This organization would work alongside existing international bodies to ensure that trade agreements, development policies, and environmental regulations all take animal capabilities into account.
The chapter also addresses the tension between animal justice and national sovereignty. Critics will argue that requiring other nations to treat animals in accordance with capabilities-based principles is a form of cultural imperialism. Nussbaum responds by distinguishing between the universal requirements of justice and the particular ways those requirements can be implemented. The capabilities approach does not demand that all cultures treat animals in exactly the same way; it allows for variation in how animals are housed, how they are integrated into human communities, and what forms of human-animal interaction are permitted. What it does demand is that every society respect the basic threshold of capabilities for the animals within its jurisdiction. This is not a demand for cultural uniformity but for the recognition of animal sentience as a source of moral claims that transcend cultural boundaries.
CLARIFY: This section extends the book’s argument from the domestic to the global level, acknowledging that animal suffering is a transnational problem that cannot be solved by individual nations acting alone. The proposal for a World Animal Organization is the most ambitious institutional recommendation in the book, and it reflects Nussbaum’s conviction that the capabilities approach has universal applicability. By engaging with the charge of cultural imperialism, she shows that the approach is respectful of cultural difference while insisting on the non-negotiable character of animal entitlements. This chapter positions animal justice as part of the broader project of global justice, alongside human rights and environmental protection.
Chapter 12: The Capabilities Approach and the Future: Hope and Hard Work
We are in the final chapter of the book, where Nussbaum shifts from the theoretical and legal arguments to the practical question of how to bring about the changes she has proposed. This is not a retreat from the book’s ambitious claims, but rather a realistic assessment of the political, economic, and cultural obstacles to animal justice.
Nussbaum begins by acknowledging the scale of the challenge. The same industrial systems that cause the most catastrophic harm to animals — factory farming, industrial fishing, wildlife trafficking, animal experimentation — are deeply entrenched in the global economy and supported by powerful political and economic interests. The number of animals affected is staggering: tens of billions of land animals killed each year for food, plus hundreds of billions of fish. To achieve the threshold of central capabilities for all of these animals would require nothing less than a fundamental transformation of the global food system, the pharmaceutical industry, and many other sectors of the economy. Nussbaum does not minimize this difficulty. As she writes: “The road to animal justice is long, and it crosses through terrain that is currently occupied by powerful armies of vested interests.” She insists, however, that the difficulty of the task does not diminish its moral urgency. The fact that change is hard does not mean it is impossible, nor does it mean we should not try.
The chapter then offers a strategic vision for how change might come about. Nussbaum emphasizes the importance of coalition-building and incremental progress. She argues that the animal justice movement should form alliances with other social justice movements — movements for environmental justice, food justice, labor rights, and human rights — because the same systems of exploitation that harm animals also harm human beings, particularly the poor and marginalized. The factory farming system, for example, is not only cruel to animals but also pollutes the environment, exploits workers, and produces unhealthy food. A coalition that brings together animal advocates, environmentalists, labor organizers, and public health experts would be more powerful than any of these groups working alone. Nussbaum also recommends a focus on low-hanging fruit: the most egregious forms of animal cruelty that can be eliminated without fundamentally disrupting the entire system. Bans on the worst confinement practices (such as gestation crates for pigs and battery cages for laying hens), restrictions on the most painful forms of slaughter, and prohibitions on the cruelest forms of animal entertainment (such as circus animals and bullfighting) are achievable goals that would make a real difference in the lives of many animals while building political momentum for more fundamental reforms.
Nussbaum also addresses the question of consumer choice and personal responsibility. She acknowledges that individual consumers can make a difference by boycotting factory-farmed products, adopting a plant-based or reduced-meat diet, and supporting companies that treat animals humanely. However, she cautions against relying too heavily on consumer activism as a strategy for systemic change. The problem is not that individual consumers are making bad choices, but that the entire food system is structured to make the cruel and cheap option the default. The most effective way to change consumer behavior is not to shame individuals but to change the incentives and regulations that shape the market. This requires political action, not just consumer choice. Nussbaum argues for a combination of strategies: regulatory reform at the government level, corporate engagement to encourage companies to adopt higher welfare standards, and cultural education to shift public attitudes about animals from seeing them as resources to recognizing them as beings with intrinsic value.
The chapter concludes by returning to the theme of hope. Nussbaum argues that hope is not naive optimism but a necessary condition for political action. Without hope, people will not make the sacrifices required to achieve animal justice. Hope, in the sense Nussbaum uses it, is the belief that the future is not predetermined and that human effort can make a difference. She draws on the work of the late political philosopher John Rawls, who argued that a “realistic utopia” — a society that is better than our own but still within the bounds of what is possible given human nature and social conditions — can serve as a guide for political action. The capabilities approach provides the blueprint for such a realistic utopia for animals: a world in which all sentient beings have the opportunity to flourish in accordance with their own natures, free from torture and deprivation, and recognized as members of the moral community. This is not a world that will be achieved overnight, or perhaps even within our lifetimes. But it is a world worth working toward, and the work must begin now.
CLARIFY: This chapter functions as the book’s conclusion, but it is not a summary. Instead, it is a strategic reflection on how to move from theory to practice. Nussbaum is acutely aware of the gap between the moral claims she has established and the political reality of entrenched animal exploitation. She does not pretend that change will be easy, but she argues that it is possible and that we have a moral obligation to pursue it. The emphasis on coalition-building and incremental reform reflects a sophisticated understanding of how social movements actually succeed — not through dramatic ruptures but through sustained pressure and the gradual accumulation of small victories. The final turn to hope is characteristic of Nussbaum’s philosophical style: she takes evil seriously but never allows it to have the last word.
