The concept of right is one of the three main concepts of practical reasoning; the other two are the concepts of value (the good) and moral worth (TJ 94). Contrary to teleological theories of justice, Rawls rejects that the concept of right can be defined in terms of any of the other two main concepts of practical reasoning. Instead Rawls follows the contractualist tradition and argues that the concept of right should be understood in terms of what appropriately situated and motivated parties would agree to. On this contractualist understanding of the concept of right, we can identify the best conception of right for a given subject by asking what principles would be agreed to by all parties in an appropriately defined initial situation (CP 59, 63, 222–223; TJ 95).

The concept of right divides according to the various domains of agency that are subjects of right, so that we can talk about the concept of right for individuals, for social systems and institutions, and for the law of nations. A special and fundamental subject of right is the basic structure of society. The concept of right for this special case is the concept of justice, the norm of proper balance between competing claims to the benefits and burdens of social cooperation. Utilitarians favor one set of principles for deciding how the competing claims to the benefits and burdens of social cooperation should be negotiated, libertarians another, perfectionists a third. Rawls argues that the principles of justice as fairness provide a superior interpretation.