Frontiers of Justice Summary: Nussbaum's Three Challenges to Rawls

What is Frontiers of Justice?

Frontiers of Justice: Disability, Nationality, Species Membership is a 2006 book by Martha Nussbaum that examines three areas in which influential theories of social justice, particularly the social contract tradition, face serious difficulties. Nussbaum focuses on people with significant disabilities, people whose lives are affected by global inequalities across national borders, and nonhuman animals. Her central claim is that these cases expose assumptions built into traditional contract theories about who counts as a participant in a political society and what makes cooperation just.

The book does not reject John Rawls's political philosophy altogether. Nussbaum takes Rawls very seriously and retains important elements of his political liberalism. Her disagreement concerns the foundation and reach of the contract model. She argues that justice should not depend on the assumption that all those to whom justice is owed are parties capable of entering a reciprocal agreement for mutual benefit.

Nussbaum therefore turns to her Capabilities Approach. Rather than asking only who can participate in a social contract, she asks what opportunities are necessary for every individual to live a life worthy of human dignity. This allows her theory to address forms of exclusion that become difficult to explain when justice begins with bargaining among approximately equal parties.

The Rawlsian starting point

In A Theory of Justice (1971), Rawls asks what principles free and equal people would choose to govern society if they did not know their particular position within it. His device is the original position, in which the parties deliberate behind a veil of ignorance. They do not know their class, wealth, talents, race, gender, religion or other particular circumstances, and this restriction is designed to prevent them from choosing principles that unfairly benefit themselves.

Rawls's approach belongs to the social contract tradition associated with thinkers such as Hobbes, Locke and Rousseau, although Rawls substantially reconstructs the tradition. His theory is concerned with the principles that should regulate the basic structure of a democratic society. See also our entry on A Theory of Justice.

Nussbaum admires Rawls and describes herself as a political liberal. However, she argues that the assumptions surrounding the original position do not adequately address people who cannot participate in social cooperation on terms of roughly equal bargaining power, people living outside the political community, or beings who cannot participate in a contract at all. These cases form the three "frontiers" examined in the book.

The social contract and mutual advantage

A social contract theory generally asks us to imagine people establishing principles of political cooperation through some form of agreement. In Rawls's version, the parties in the original position are treated as free and equal moral persons capable of participating in the construction of principles that will govern their shared institutions. The device is not meant as a historical claim that actual societies were literally created through such a bargain.

Nussbaum's concern is that this model can make reciprocity and cooperation appear more fundamental than they should be. If the imagined contractors are assumed to be roughly capable of contributing to social cooperation, what happens to someone who requires extensive care throughout life? If the parties are assumed to be members of one political society, what principles govern people born outside that society? And if the contractors are human, what moral basis remains for justice toward animals?

Nussbaum's argument is not that cooperation, reciprocity or agreement have no moral importance. Instead, she argues that they cannot be the ultimate basis for determining who is entitled to justice. A theory of justice must be able to explain why people who cannot bargain on equal terms can still possess strong claims against institutions and other agents.

The three frontiers of justice

Nussbaum identifies three major areas where traditional contractarian thinking faces difficulties. They are different problems, but they share a common structure: each involves beings or relationships that do not fit easily into the picture of independent, approximately equal parties cooperating for mutual advantage.

These three frontiers also show why Nussbaum believes the scope of justice should be determined by the claims of vulnerable beings rather than by the limits of a particular bargaining model. The three cases are distinct and require different institutional responses, but the capabilities framework gives Nussbaum a common language for addressing all of them.

Disability and care

The first frontier concerns people with physical and cognitive disabilities. If citizens are imagined primarily as independent, rational and mutually productive participants in a system of cooperation, people with severe impairments can appear to fall outside the original contract. Nussbaum argues that this is not merely a problem of applying justice to an unusual group; it reveals a deeper limitation in the assumptions used to construct the theory in the first place.

Nussbaum draws on feminist work on dependency and care, including Eva Kittay's analysis of dependency, to argue that human beings are vulnerable to dependence throughout life. Children, elderly people and people with significant disabilities may require substantial care, while almost anyone can become dependent through illness or injury. A just society therefore cannot treat care as an economically invisible activity performed outside the main structure of justice.

This also has a gender dimension because unpaid and underpaid care work has historically fallen disproportionately on women. Justice must therefore consider both the person receiving care and the person providing it. Nussbaum's capability framework asks what each person is actually able to do and be with appropriate social support, rather than judging people by their ability to contribute economically to a system of cooperation.

Nationality and global justice

The second frontier concerns the moral significance of national borders. Rawls addressed international relations in The Law of Peoples (1999), but Nussbaum argues that a theory of global justice needs to take more seriously the enormous inequalities in capabilities that exist between people living in different countries. The fact that someone was born on one side of a border rather than another can profoundly affect health, education, security, political freedom and economic opportunity.

Nussbaum's cosmopolitan argument begins from the idea that the basic claims of human beings do not disappear at national boundaries. A person's nationality is morally relevant to political institutions, but it should not determine whether that person's basic human capabilities matter at all. Severe global deprivation therefore creates responsibilities that extend beyond the domestic state.

These responsibilities are not assigned only to individual citizens of wealthy countries. Nussbaum considers the roles of states, international institutions, multinational corporations and other powerful organizations. Her position is therefore concerned with the structures that produce and maintain global inequality, not simply with individual acts of charity. This connects with the Stoic tradition of cosmopolitanism that also informs her later work on global justice.

Species membership and animal justice

The third frontier concerns nonhuman animals. Social contract theories generally begin with human beings capable of reasoning, bargaining and participating in reciprocal agreements. Animals cannot participate in such an agreement, so they can appear outside the direct scope of contractual justice.

Nussbaum argues that this is an inadequate basis for excluding animals from justice. Animals can experience suffering, have interests and pursue species-specific forms of activity and flourishing. A capability approach can therefore ask what each kind of animal needs to live a life appropriate to its species rather than asking whether the animal can participate in a human political bargain.

Her position differs in emphasis from utilitarian approaches associated with Peter Singer. Singer's animal ethics is strongly concerned with suffering and the equal consideration of interests, whereas Nussbaum's approach emphasizes the opportunity for animals to flourish according to their characteristic forms of life. For a direct comparison, see Nussbaum vs Singer.

Human dignity as an alternative foundation

Nussbaum's response to the three frontiers begins with a different question from the social contract model. Instead of first asking which beings can participate in a reciprocal agreement, she asks what conditions are necessary for a life worthy of human dignity. This makes the moral standing of a person independent of their productivity, bargaining power or ability to contribute to social cooperation.

The idea of dignity is connected to Nussbaum's list of central capabilities. Justice requires that people have genuine opportunities to live in ways consistent with basic human dignity. These include opportunities relating to life, bodily health, bodily integrity, thought, emotion, practical reason, affiliation, relations with nature, play and control over one's political and material environment.

This foundation is particularly important for the three frontiers because the people or beings involved cannot all be represented as equal contractors. Someone with profound cognitive disabilities does not lose their claim to justice because they cannot bargain. A person born in a poorer country does not lose their basic moral status because they belong to another nation. And an animal does not become morally irrelevant simply because it cannot participate in a human political agreement.

Nussbaum's alternative: the Capabilities Approach

Instead of grounding justice in a contract among mutually cooperating parties, Nussbaum applies the Capabilities Approach to the three frontiers. The basic question becomes whether each individual has the opportunity to achieve central forms of functioning appropriate to a dignified life. The theory therefore focuses on what people are actually able to do and to be, not simply on what resources they possess or what agreements they could hypothetically make.

For human beings, Nussbaum proposes a threshold of ten central capabilities that political institutions should secure. The threshold is intended as a minimum condition of justice rather than a complete account of the good life. People remain free to choose different functionings once the relevant opportunities are secured.

This distinction is particularly important for avoiding paternalism. The theory does not require everyone to use every capability in the same way. A government can protect the capability for political participation without forcing someone to vote, or protect educational opportunity without forcing someone to pursue a particular career. The aim is to secure the freedom to choose rather than prescribe a single life plan.

Political liberalism and overlapping consensus

Nussbaum's theory is not simply an attempt to impose her personal philosophical conception of human flourishing on everyone. She identifies herself with political liberalism and wants the political principles of justice to be compatible with citizens holding different religious, philosophical and moral doctrines.

Her capabilities are therefore presented as political principles that can be supported from different comprehensive viewpoints. The idea of an overlapping consensus, developed in Rawls's later political philosophy, is important here. People may disagree about why a capability is valuable or what ultimately makes life meaningful while still agreeing that institutions should protect a basic level of it.

This allows Nussbaum to combine a substantive account of minimum justice with pluralism about how individuals should live. The state establishes a floor of basic opportunities, but it does not have to determine everything above that floor.

Criticisms and replies

Frontiers of Justice has generated important debate because Nussbaum's alternative raises its own questions. Critics do not all reject the three problems she identifies; some instead argue that the social contract tradition can be modified to address them without abandoning its central ideas.

• Rawlsians say that the contract model can be extended. Additional stages or principles could potentially address dependency, disability or international justice without abandoning the original framework.
• Global justice critics ask how far international obligations should extend and how responsibilities should be divided among states, institutions, corporations and individuals.
• List objection. Critics of the Capabilities Approach question whether Nussbaum's list of central capabilities can claim universal authority across cultures and traditions.
• Measurement objection. Capabilities such as affiliation, practical reason and emotional development are considerably harder to measure than income or other conventional economic indicators.
• Animal ethics objection. Some critics question how species-specific flourishing should be defined and how conflicts between human interests and animal interests should be resolved.
• Nussbaum's reply. She argues that extending a contract model to cover cases for which its original assumptions were not designed can reveal deeper limitations, while the capabilities framework starts directly from the moral claims of vulnerable beings.

Why Frontiers of Justice matters

Frontiers of Justice matters because it asks a fundamental question about the boundaries of justice: who gets included when we construct a theory of a just society? Nussbaum argues that theories can appear universal while quietly building exclusions into their starting assumptions. Disability, nationality and species membership make those exclusions visible.

The book also expands the meaning of political equality. Equality is not simply about giving everyone identical resources or treating everyone according to the same formal rules. If people begin from very different physical, social or political circumstances, identical treatment may leave some people without meaningful opportunities. Justice therefore requires attention to the actual capabilities people possess.

The three frontiers also connect several areas of Nussbaum's philosophy: her work on human dignity, the Capabilities Approach, feminism, global justice, dependency and animal ethics. Frontiers of Justice is therefore important not only as a criticism of Rawls but as an attempt to broaden the scope of contemporary theories of justice.

Frequently asked questions

What is Frontiers of Justice about?

Frontiers of Justice is Martha Nussbaum's 2006 examination of three problems that she argues traditional social contract theories do not adequately resolve: justice for people with disabilities, justice across national borders and justice for nonhuman animals.

What are the three frontiers of justice?

The three frontiers are disability, nationality and species membership. Nussbaum uses them to examine who is included within theories of justice and whether traditional assumptions about reciprocal cooperation are sufficient.

Why does Nussbaum criticize Rawls?

Nussbaum argues that Rawls's contract model begins with assumptions about free and equal citizens participating in social cooperation, and that these assumptions do not adequately explain justice for people with significant disabilities, people outside the national political community or nonhuman animals.

Does Nussbaum reject Rawls completely?

No. Nussbaum is strongly influenced by Rawls and retains important elements of his political liberalism. Her criticism is directed primarily at the limits of the social contract as the foundational method for determining who is owed justice and what justice requires.

What does Nussbaum offer instead?

Nussbaum applies the Capabilities Approach, which evaluates justice by the real opportunities available to individuals. For human beings, she argues for a minimum threshold of ten central capabilities connected to human dignity.

Why is disability important in Frontiers of Justice?

Disability exposes the difficulty of grounding justice in reciprocal cooperation among approximately equal parties. Nussbaum argues that people who require substantial care are still full subjects of justice and that caregivers also deserve social and economic support.

What does Nussbaum say about global justice?

Nussbaum argues that national borders cannot eliminate the basic moral claims of people living elsewhere. Global justice therefore requires attention to severe inequalities in capabilities and to the responsibilities of states, international institutions and other powerful actors.

Why does Nussbaum include animals?

Nussbaum argues that animals can be wronged and have species-specific forms of flourishing. Because animals cannot participate in a human social contract, a theory of justice based solely on contractual participation risks excluding them from direct moral consideration.