On A Theory of Justice

John Rawls's A Theory of Justice, published in 1971, revived political philosophy as a serious discipline almost single-handedly and remains the most important work of political theory of the twentieth century. Its question is the oldest one in political philosophy, what makes a society just, and its answer is built on a thought experiment so powerful that it has shaped how educated people argue about fairness ever since, often without knowing its source. Rawls asks us to design the basic rules of a society without knowing what place in it we ourselves would occupy.

This is the famous device of the original position behind a veil of ignorance. Imagine, Rawls says, that you must choose the fundamental principles governing a society, the rules determining rights, liberties, and the distribution of wealth and opportunity, but you must choose them without knowing who you will be in that society: your class, your race, your sex, your talents, your religion, your conception of the good life, even your generation, all hidden from you. Stripped of the knowledge of your own situation, you cannot rig the rules in your own favor, because you do not know what favoring yourself would mean. Whatever principles a rational person would choose under that veil, Rawls argues, are the principles of justice, because they are chosen fairly, from a position no one could tilt toward their own advantage.

What would such people choose? Rawls argues they would settle on two principles. First, each person should have the most extensive basic liberties compatible with the same liberties for all, the freedoms of conscience, speech, political participation, and the rest, guaranteed equally and not to be traded away. Second, social and economic inequalities are permissible only if they are attached to positions open to all under fair equality of opportunity, and only if they work to the greatest benefit of the least advantaged members of society. This last idea, that inequalities are just only insofar as they help those at the bottom, is the celebrated and contested difference principle, and it gives a rigorous foundation to a politics of fairness toward the worst-off.

The genius of the approach is that it makes fairness concrete. We argue endlessly about what a just distribution of rights and resources would be, each of us influenced, consciously or not, by our own interests. Rawls's veil of ignorance is a way to subtract that bias, to ask what we would accept if we did not know whether we would be rich or poor, powerful or weak, and his answer is a society that secures liberty for all and arranges its inequalities to benefit the least fortunate. The framework has been challenged from every direction, and the libertarian and communitarian responses to it are themselves major works, but the terms of the debate were set by Rawls.

The book belongs at the philosophical heart of this library, the modern foundation for thinking rigorously about what a just society owes its members. It sits with Dworkin, Sen, and the older political philosophers throughout the collection. A Theory of Justice is in copyright and widely available in print and digital editions. It is demanding and best read with patience, but the central device, designing society from behind the veil of ignorance, is one of the most useful tools for moral and political reasoning ever devised. Read it to learn to ask what rules you would accept if you did not know who you would be.