Reflective equilibrium is a state of balance or coherence among a set of beliefs arrived at by a process of deliberative mutual adjustment among general principles and particular judgements. Although he did not use the term, philosopher Nelson Goodman introduced the method of reflective equilibrium as an approach to justifying the principles of inductive logic (this is now known as Goodman's method<!--boldface per WP:R#PLA-->). The term reflective equilibrium was coined by John Rawls and popularized in his A Theory of Justice as a method for arriving at the content of the principles of justice.
has pointed out that there are many interpretations of reflective equilibrium that deviate from Rawls' method in ways that reduce the cogency of the idea. Among these misinterpretations, according to Hübner, are definitions of reflective equilibrium as "(a) balancing theoretical accounts against intuitive convictions; (b) balancing general principles against particular judgements; (c) balancing opposite ethical conceptions or divergent moral statements".
Rawls applied this technique to his conception of a hypothetical original position from which people would agree to a social contract. He arrived at the conclusion that the optimal theory of justice is the one to which people would agree from behind a veil of ignorance, not knowing their social positions.
Wide reflective equilibrium
<!--Wide reflective equilibrium redirects here (MOS:HEAD)-->
Wide reflective equilibrium, first introduced by Rawls, has been described by Norman Daniels as "a method that attempts to produce coherence in ordered triple sets of beliefs held by a particular person, namely: (a) a set of considered moral judgments, (b) a set of moral principles, and (c) a set of relevant (scientific and philosophical) background theories".
Relation to constructivism
Kai Nielsen has asserted that "philosophers who are defenders of reflective equilibrium are also constructivists", in response to what he considered to be the misconception that reflective equilibrium works with some necessarily preexisting coherent system of moral beliefs and practices: