1. Plato's Justice
In The Republic, Plato defines justice as each part of the soul — and each class of the city — performing its proper function. The just city has three classes: producers (workers), guardians (warriors), and philosopher-rulers. Justice consists in each class doing what it is naturally suited to do, without interfering with the others. The just individual mirrors this structure: reason rules, spirit supports reason, and appetite is guided by both.
Plato argues that justice is not merely a social convention or a matter of contracts (as Thrasymachus and Glaucon suggest), but an intrinsic good. A just person is happier than an unjust person, because justice brings harmony to the soul. The unjust soul is in turmoil, ruled by appetite or passion rather than reason. Plato's vision is deeply hierarchical and essentialist: justice is tied to natural abilities and social roles.
Critics object that Plato's justice is authoritarian — it justifies rigid class divisions and the rule of an elite. Aristotle, while influenced by Plato, offered a more egalitarian account. Modern egalitarians find Plato's naturalism troubling: the idea that people have fixed natures that determine their social roles conflicts with contemporary commitments to equal opportunity and social mobility.
2. Aristotle's Distributive Justice
Aristotle distinguished between distributive justice (the fair distribution of goods and honors) and corrective justice (the rectification of wrongs in transactions and crimes). Distributive justice is based on proportionality, not equality: goods should be distributed according to merit or desert. A talented musician deserves more recognition than an untalented one; a brave soldier deserves more honor than a coward.
Aristotle's distributive justice is teleological: it aims at the good of the community. The polis exists to promote the good life, and justice requires that resources be allocated in a way that serves this end. This is not utilitarianism (the greatest good for the greatest number) but a more nuanced view: justice requires giving each person what they are due, relative to their contribution to the common good.
Aristotle's account raises the question: who determines merit, and according to what criteria? His answer — that the virtuous citizen determines what is just — seems circular. Modern critics argue that Aristotle's framework is too vague and too dependent on contested values to provide actionable guidance. Nevertheless, his distinction between distributive and corrective justice remains foundational.
3. Social Contract and Justice
The social contract tradition holds that justice arises from agreements among individuals to form a society. Thomas Hobbes argued in Leviathan (1651) that in the state of nature, life is "solitary, poor, nasty, brutish, and short." Rational individuals agree to surrender their natural liberty to a sovereign in exchange for security and order. Justice, for Hobbes, consists in keeping the contracts one has made and obeying the sovereign.
John Locke offered a more liberal version: individuals have natural rights to life, liberty, and property, and the social contract exists to protect these rights. If the government fails to do so, citizens have a right to revolt. Rousseau, in The Social Contract (1762), argued that legitimate political authority must be based on the "general will" — the collective interest of the people, not the will of a ruler or the sum of private interests.
These three views — Hobbes's authoritarianism, Locke's liberalism, and Rousseau's democratic egalitarianism — represent different interpretations of what the social contract requires. All agree that justice is grounded in consent and mutual advantage, but they disagree sharply about what justice demands in practice.
4. Rawls: Justice as Fairness
John Rawls' A Theory of Justice (1971) is the most influential work of political philosophy in the twentieth century. Rawls proposes a thought experiment: imagine rational individuals choosing the principles of justice for their society from behind a "veil of ignorance" — they do not know their own race, gender, talents, social class, or conception of the good. This "original position" ensures that the principles chosen are fair to everyone.
Rawls argues that people in the original position would choose two principles: (1) each person has an equal right to the most extensive basic liberties compatible with similar liberties for others; (2) social and economic inequalities are permissible only if they benefit the least advantaged members of society (the "difference principle"). These principles rank liberty first, then equality of opportunity, then the difference principle.
Rawls' theory has been enormously influential but also widely criticized. Libertarians like Robert Nozick argue that the difference principle violates individual rights by redistributing wealth. Communitarians like Michael Sandel argue that the original position is unrealistically abstract — real people are embedded in communities with shared values. Feminists and critical race theorists argue that Rawls' framework fails to address structural oppression and historical injustice.
5. Nozick: Entitlement Theory
Robert Nozick, in Anarchy, State, and Utopia (1974), offers a libertarian alternative to Rawls. Nozick's entitlement theory holds that justice in holdings is based on three principles: justice in acquisition (how unowned things become owned), justice in transfer (how holdings change hands), and rectification of injustice (how to correct past wrongs). If your holdings were acquired and transferred justly, you are entitled to them, regardless of how unequal the distribution is.
Nozick famously argues that taxation of the wealthy to fund social programs is "on a par with forced labor." If I earn $100 and the government takes $30 to give to someone else, it is as if I worked three hours for someone else's benefit against my will. This violates my self-ownership. The only legitimate state, for Nozick, is a "minimal state" — limited to protecting against force, theft, and fraud, and enforcing contracts.
Critics argue that Nozick's theory ignores the role of luck, inheritance, and structural advantage in determining outcomes. Rawls responds that no one deserves their natural talents — they are "arbitrary from a moral point of view" — and therefore the distribution of talents does not, by itself, justify unequal outcomes. The debate between Rawls and Nozick remains central to contemporary political philosophy.
6. Utilitarian Justice
Utilitarianism, as developed by Jeremy Bentham and John Stuart Mill, holds that justice is ultimately a matter of maximizing overall happiness or well-being. Bentham dismissed natural rights as "nonsense upon stilts" and argued that the only rational basis for law and policy is the principle of utility: the greatest good for the greatest number. Justice is not a separate principle but a useful social tool for promoting overall welfare.
Mill attempted to reconcile utilitarianism with justice in Utilitarianism (1863). He argued that justice rules (like respecting persons' rights) are useful generalizations that promote utility in the long run. We feel the force of justice because the rules it embodies — do not steal, do not harm — are essential for social cooperation and individual security. Justice is not a separate principle but a useful social tool for promoting overall welfare.
Critics argue that utilitarianism can justify injustice: if sacrificing one innocent person would produce enough happiness for others, utilitarianism seems to require it. Rawls calls utilitarianism "not serious about the distinction between persons" because it aggregates happiness across individuals rather than respecting each person's dignity. Defenders respond that a sophisticated utilitarianism would never permit such sacrifices, because the long-term costs to social trust would outweigh the short-term gains.
7. Marxist Justice
Karl Marx argued that justice under capitalism is an ideological concept — it serves the interests of the ruling class by making exploitative relations appear natural and fair. The "justice" of capitalist society is the justice of property rights, which protect the ownership of the means of production by a small minority. Marx contended that wage labor is inherently exploitative: workers produce more value than they receive in wages, and the surplus is appropriated by capitalists.
Marx's critique goes beyond inequality to the structure of capitalist production itself. In Capital (1867), he analyzed how the commodity form, the labor theory of value, and the accumulation of capital create a system in which exploitation is not a bug but a feature. Justice, for Marx, is not about redistributing wealth within capitalism but about transforming the relations of production through revolution.
Contemporary Marxists and socialists have developed various accounts of justice. G.A. Cohen argued for a principle of egalitarian justice that goes beyond Rawls to address inequalities of talent and opportunity. Others, like Iris Marion Young, have focused on structural oppression and the ways in which capitalist societies perpetuate domination through their economic institutions.
8. Feminist Justice
Feminist philosophers argue that traditional theories of justice have systematically ignored or marginalized the experiences and interests of women. Simone de Beauvoir, in The Second Sex (1949), analyzed how women are constructed as "the Other" in patriarchal societies — defined in relation to men rather than as autonomous subjects. Justice requires not merely formal equality but the dismantling of structures that perpetuate gender hierarchy.
Iris Marion Young identified five faces of oppression: exploitation, marginalization, powerlessness, cultural imperialism, and violence. These forms of oppression are structural, not merely interpersonal, and require structural responses. Justice, for Young, is not just about fair distribution but about addressing the institutional mechanisms that produce and reproduce domination.
Eva Feder Kittay has argued that care work — the unpaid labor of caring for children, the elderly, and the sick — is essential to social functioning but systematically undervalued. A just society must recognize and redistribute the burdens of care. This critique challenges both liberal and Marxist theories, which tend to focus on market work and production rather than the relational labor that makes production possible.
9. Global Justice
Global justice asks: what obligations do we have to people in other countries? Thomas Pogge argues that the existing global order — including trade rules, intellectual property rights, and resource extraction — actively harms the world's poorest people. He proposes a "Global Resources Dividend": a tax on resource extraction that would fund basic needs for the global poor. Pogge's approach is institutional rather than aid-based: the problem is not that we fail to help the poor, but that we actively harm them.
Peter Singer takes a different approach. In Famine, Affluence, and Morality (1972), he argues that if it is in our power to prevent suffering — for instance, by donating to famine relief — without sacrificing anything of comparable moral significance, we are morally obligated to do so. Singer's argument is consequentialist: what matters is the outcome, not the distinction between "our" people and "their" people.
Critics of global justice theories argue that national sovereignty, cultural differences, and the limits of human motivation make such obligations unrealistic. Some, like Michael Walzer, argue that communities have special obligations to their own members that override cosmopolitan duties. The debate between cosmopolitanism and communitarianism remains central to the ethics of global justice.
10. Restorative Justice
Restorative justice shifts the focus of criminal justice from punishment to healing. Rather than asking "what law was broken, who broke it, and what punishment do they deserve?", restorative justice asks: "who was harmed, what are their needs, and whose obligation is it to meet those needs?" This approach centers the victim and the community rather than the state.
Restorative practices include victim-offender mediation, community conferencing, and sentencing circles. These processes give victims a voice, hold offenders accountable in a way that promotes understanding rather than resentment, and engage the community in repairing harm. Research suggests that restorative justice can reduce recidivism, increase victim satisfaction, and promote community cohesion more effectively than traditional punitive approaches.
Critics argue that restorative justice is too lenient on serious crimes and may fail to protect victims or deter future offending. Others worry that it may pressure victims into forgiving offenders or may be co-opted by states seeking to reduce the costs of incarceration. Defenders respond that restorative justice, properly implemented, can be more demanding than punishment, because it requires offenders to face the human consequences of their actions rather than simply serving time.