John Rawls was one of the greatest and most influential political philosophers of the last century. At a time when political philosophy was dominated by utilitarians on the one hand and Marxists on the other, he created a new way of thinking about fundamental questions of justice. In so doing he revived both the field of political philosophy and the idea that it was possible to do interesting work in moral philosophy not just by analyzing terms, but by constructing a substantive theory.

The main question Rawls tried to answer was: How can you tell whether the most basic institutions of a society are just? By what principles should you assess them? He was not concerned with assessing individual actions, or with justifying ad hoc redistributions, but with the institutions that structure our lives: the Constitution, the family, the market.

Rawls’s famous answer is that a just system is one that would be chosen by people in an imaginary situation that he calls the “Original Position.” In the Original Position, people know all sorts of general facts about the world: science, economics, psychology and so forth. However, they do not know any particular facts about themselves: their race, their gender, their talents, or their religion and values. They could be anyone.

The parties to the Original Position know that they have some conception of the kind of life they want to lead, and they want to ensure that they are in a position to lead it. But they do not know what it is. They do know, however, that there are some things that are generally useful for almost any plan of life: liberty, opportunity, income and wealth, and what Rawls calls “the social bases of self-respect.” To make sure that they will be able to live the lives they want to live, they would therefore try to choose principles that ensure that whoever they turn out to be, they will have those things. Rawls argues that they would first protect their basic liberties, then ensure genuine equality of opportunity, and finally allow any further inequalities only if the least well-off members of society would be better off with those inequalities than without them.

Since the Original Position is wholly imaginary, why should we care what people would choose if they were in it? For Rawls, the point is “simply to make vivid to ourselves the restrictions that it seems reasonable to impose on arguments for principles of justice, and therefore on these principles themselves.” If I accept some principle of justice only because of facts about my gender, my profession, my talents, and so forth, then I have no good reasons for accepting it at all. By excluding knowledge of these facts from the Original Position, Rawls ensures that facts that we do not regard as reasons for choosing one principle over another play no role in our decision.

Many people would agree that we should not accept some principle of justice only because it would give advantages to people with our particular constellation of talents or to people of our race or gender. But is religion a different matter? Why should, say, Catholics or Muslims base their views of justice on an imaginary contract that requires that they choose as if they did not know that God exists, or what he thinks justice requires?

Rawls has an answer to this question: It is precisely because religion matters so much to us that the parties to the Original Position choose to protect their religious freedom. If you know that you might hold some religious view, and that if you do, you will probably take it seriously, then you cannot afford to gamble with your freedom to practice it. If you knew that you would be part of a religious majority, then you might be tempted to structure your society in accordance with the dictates of your religion. But because you do not know what religion (if any) you follow, or how many others share your views, you will not want to risk not being able to live by your faith. Instead, you will choose principles that secure your (and everyone’s) freedom of religion.

Still, believers might wonder whether this reply does justice to their views. And since liberalism is often thought of as a secular philosophy, they might also wonder whether Rawls really understood how important religion is to a believer. A Brief Inquiry into the Meaning of Sin and Faith should answer that question once and for all.

The heart of the book is Rawls’s undergraduate thesis, written at a time when he was a very devout Episcopalian. In their introduction, Joshua Cohen and Thomas Nagel accurately describe Rawls’s thesis as “an extraordinary work for a 21-year-old, animated by youthful passion and powerful ethical conviction.” It is written in a much more personal style than Rawls’s later work. Rawls has found an idea that he thinks is very important; in his preface he writes that “we are proposing more or less of a ‘revolution.’” Reading it, one can feel the young Rawls strapping on the breastplate of truth and sallying forth to defend this idea, as well as his frustration when he feels he cannot do it justice. And while in his later work Rawls keeps his own religious views to himself, in the thesis he wears them on his sleeve. He begins by stating his presuppositions, the first of which is “that there is a being whom Christians call God and who has revealed Himself in Christ Jesus.”

Rawls’s thesis centers on the distinction between what he calls the “natural” and the “personal,” a distinction that he believes is crucial for understanding human life and Christianity, but which many philosophers and theologians, including Augustine and Aquinas, have neglected. Marking this distinction clearly and explaining its importance is the “revolution” that Rawls proposes.

Rawls does not use the term “natural” in the ordinary sense, in which it refers to what can be described and explained in terms of the natural sciences. Instead, he defines it as one of three kinds of relations: the causal relations in which two objects can stand to one another; natural relations, which include the various relations in which persons can stand to objects; and personal relations, which can only exist between persons. Natural relations include perceiving something, desiring it, fearing it, wanting to avoid it, and so on. The natural cosmos, for Rawls, is “any universe in which all of the relations are conceived of in natural terms.”

Others resemble us, first and foremost, in being active participants in our relationships to them. Consider the difference between taking a hike alone and taking one with a friend. When you hike alone, you decide where to go. If one path appeals to you more than another, then you take it. When you hike with a friend, by contrast, the two of you choose your path together. You might end up taking the path you would have chosen if left to yourself, but then again, you might not. Likewise, if you decide that you want a new car, the car has no say in the matter. But if you decide that you want to be someone’s friend, that person can choose whether or not to accept your friendship, and if she accepts, the two of you will jointly determine its course.

Rawls believes that our capacity to enter into these kinds of reciprocal relationships with others is what makes us human: “The distinctive thing about man is not his reason, not his appreciation of beauty, not his various powers; no, man’s distinctiveness from other worldly creatures is that he was made for community and that he is a personality necessarily related to community.”

We sin when we destroy community, which we can do in two ways. First, our personal relationships can be the kind that destroy community: hatred, envy, anger. Second, we can treat other persons as though they were mere objects of desire and aversion. If we regard people in this way, then we will not see them specifically as persons, and we will inhabit a solitary, solipsistic world.

The result of sin is what Rawls calls “aloneness.” His descriptions of it are strikingly personal: “Take a fish out of water and it dies; extract man from community and man dies likewise. Aloneness, to which sin leads, is that spiritual death on the border of which all of us sinful men live. This precipice is always at our side. Some of us have fallen over it; others of us sit along its side, dangling our feet over the space below.”

If sin is solitude, then salvation, for Rawls, is the establishment of community between ourselves and God. This is not a matter of belief: Belief is an attitude toward propositions, while faith is a relationship between ourselves and God. Nor is faith a matter of coming to recognize that our desires should be directed not to pleasure or worldly glory, but to God. To see God in this light is, for Rawls, a deep error, and one that he attributes to Augustine, Aquinas, and others. God is not the most desirable of all objects. He is a person, whom we should not desire but love.

And because the relationship to God is a personal one, he must be active in it. Rawls believes we often try to avoid thinking of our relationship with God in this way: We try to strike bargains with him, or to figure out what good conduct of ours will cause him to approve of us. These unilateral efforts are, to Rawls, doomed to failure, since they rely on our regarding God as an object to be manipulated, and not as a person. We can be restored to community only when God bursts in on our solitude, and we lie in his presence, flattened and exposed, and accept his gift of love.

Rawls’s religious beliefs did not survive his experiences in World War II. He describes this change in “On My Religion,” written in the 1990s and also published in this volume. After the Holocaust, he found it impossible to believe that history was directed by a just God. Moreover, a close friend was killed while on a mission that Rawls himself might have been sent on but for blind luck. This might have had particular resonance for Rawls since it was not the first time that luck had favored him while striking down someone he loved: When he was a child, two of his four brothers died of diseases they had contracted from him.

Though Rawls abandoned his religious views, some of the central themes of his undergraduate thesis appear in secular form in his later work. One of Rawls’s aims in his undergraduate thesis is to show that if we conceive of our relations to other beings simply in terms of desire, aversion, and the other relations he calls “natural,” we cannot understand either Christianity or ourselves. Rawls argues that naturalism “excludes personality, community, and God, although it may use His name,” and leaves out “the spiritual and personal element which forms the deep inner core of the universe.” Rawls wants to show what naturalism leaves out, and to present an alternative.

In A Theory of Justice, Rawls tries to construct an alternative to utilitarianism, which is the view that we should always do what maximizes happiness. Most utilitarians define happiness either as pleasure and the avoidance of pain, or as the satisfaction of our desires. Both wanting something and taking pleasure or pain in it are, in Rawls’s terms, natural relations, and utilitarians think that everything that matters morally can be derived from them. Morality, for utilitarians, simply requires that we take everyone’s happiness into account. Utilitarianism is, in Rawls’s sense, a form of naturalism.

Rawls finds this view as unsatisfying in his later work as he does in his thesis, and for similar reasons. Utilitarianism notoriously implies that we should maximize happiness even when doing so involves making some people suffer, and even when those people will not themselves enjoy any benefit from their suffering. Rawls argues that this is wrong. It applies to all people a standard of rationality appropriate to a single individual, and so “does not take seriously the distinction between persons.” Where there are no distinct persons, there can be no personal relations, and no community.

In his thesis, there is no evidence that Rawls thought that questions like “what should I do?” or “how should political institutions be structured?” would be particularly difficult to answer once one had turned away from sin and opened one’s heart to God. Since Rawls spent the rest of his life trying to work out detailed answers to some of these questions, he plainly changed his mind on this point. But his concern for the kinds of personal relations he described in his thesis remained constant. One way to describe his later work is as a sustained attempt to work out what a society would have to be like in order for the relations between its citizens to be, in his sense, personal rather than natural.

In such a society, citizens would regard one another as jointly determining the structure of their society under conditions that respect each of them as autonomous persons, and that they themselves regard as fair. They would view their fellow citizens as persons whose individual interests must be taken seriously, not just lumped together in an aggregate to be maximized, or sacrificed for a larger good. They would want the least well-off among them to know that their basic liberties were protected, that they could compete on a level playing field, and that the inequalities that separate them from others were to their benefit. As Rawls wrote in A Theory of Justice, a society that meets these principles “comes as close as a society can to being a voluntary scheme, for it meets the principles which free and equal persons would assent to under circumstances that are fair. In this sense its members are autonomous and the obligations they recognize self-imposed.”

In his thesis, Rawls writes that “the elect are chosen to re-establish the community”: a community based not on natural relations or mutual advantage, but on the personal relations of reciprocity, respect, and love. While he gave up his religious beliefs, he never abandoned this task. Trying to explain what such a community would be like, and to show that it could not just accommodate but perfect its members’ individuality, was his life’s work. To paraphrase Adrienne Rich: “Without faith, he was faithful.”