What Is Reflective Equilibrium? A Fresh Look Based Upon a Formal Model

Reflective equilibrium (RE) is often taken to be a fruitful method in the foundations of logic (N. Goodman) and in the philosophy of science (J. Ladyman). Some authors have even gone as far as to recommend it for philosophy (D. Lewis) or understanding more generally (C. Elgin). But what exactly is reflective equilibrium? Despite its apparent popularity, the method is only vaguely characterized, poorly developed and almost never applied to real-world problems in an open-minded spirit.
The aim of this lecture is to make progress in our conception of RE. The starting point is an informal characterization of what I take to be the key idea of RE, viz. an elaboration of one's commitments due to pressure from a systematic theory. This key idea is spelled out using a formal model. It has been developed in the framework of the Theory of Dialectical Structures proposed by G. Betz. In the model, the commitments of an epistemic agent as well as theories are described as positions in a dialectical structure, respectively; desiderata for the commitments, the theories and their relationship are formulated, and a dynamics for the mutual adjustment of commitments and principles is defined. Simple examples, in which the model is applied, display a number of features that are well-known from the literature about RE. But they raise interesting systematic questions too. The lecture concludes by discussing how the model advances our understanding of RE. - The lecture is based upon work done jointly with G. Betz and G. Brun.