The notion of a well-ordered society has been a central idea in Rawls’s thinking about justice at least since his great opus, A Theory of Justice, in which it plays a crucial role. The core idea of a well-ordered society is a society whose citizens all accept the same conception of justice, its institutions actually conform to that conception, and both of these facts are publicly known. By envisioning different societies, each organized by a particular conception of justice, and so each “well-ordered” in terms of that conception, we can get some traction on the question of which of the many conflicting conceptions of justice is the most reasonable, is the most worthy of adoption. Over time the idea of a well-ordered society has come to play an increasingly important role. In Justice as Fairness: A Restatement, Rawls presents the idea of a “well-ordered society” as one of two “companion fundamental ideas” to the “most fundamental idea in [his] conception of justice,” which is the “idea of society as a fair system of social cooperation” (JF 5). (The second companion idea is the “idea of citizens…as free and equal persons.”) Rawls offers a definition or explication of this term in each of his major writings, and in many papers as well. Though there are slight differences among these formulations, the core idea has remained fairly stable.