Prof. Dr. Dr. Beisbart, Claus

How Far Does Reflective Equilibrium Take Us?



Beisbart, Claus; Betz, Gregor; Brun, Georg (2021). Making Reflective Equilibrium Precise. A Formal Model. Ergo 8/15, 441–72.

Reflective equilibrium (RE) is often regarded as a powerful method in ethics, logic, and even philosophy in general. Despite this popularity, characterizations of the method have been fairly vague and unspecific so far. It thus may be doubted whether RE is more than a jumble of appealing but ultimately sketchy ideas that cannot be spelled out consistently. In this paper, we dispel such doubts by devising a formal model of RE. The model contains as components the agent’s commitments and a theory that tries to systematize the commitments. It yields a precise picture of how the commitments and the theory are adjusted to each other. The model differentiates between equilibrium as a target state and the dynamic equilibration process. First solutions to the model, obtained by computer simulation, show that the method allows for consistent specification and that the model’s implications are plausible in view of expectations on RE. In particular, the mutual adjustment of commitments and theory can improve one’s commitments, as proponents of RE have suggested. We argue that our model is fruitful not only because it points to issues that need to be dealt with for a better understanding of RE, but also because it provides the means to address these issues.


Freivogel, Andreas. 2021. “Modelling Reflective Equilibrium with Belief Revision Theory”. In Blicha, Martin; Igor Sedlár (eds). 2021. The Logica Yearbook 2020. London: College Publications. 65–80.

This article brings together two different topics: reflective equilibrium (RE) and belief revision theory (BRT). RE is a popular method of justification in many areas of philosophy, it involves a process of mutual adjustments striving for a state of coherence, but it lacks formally rigorous elaborations and faces severe criticism. To elucidate core elements of RE and provide a solid basis to address objections, a formal model of RE within BRT is presented. A fruitful starting point to the formalization of RE is Olsson’s coherentist interpretation of semi-revision, but it does not come with a comparative notion of stability. This paper develops an account of comparative stability in an RE setting for belief changing operations, which satisfy postulates of rational belief change, and characterize RE states and processes.


Brun, Georg. 2022.  Re-Engineering Contested Concepts. A Reflective-Equilibrium Approach. Synthese.

Social scientists, political scientists and philosophers debate key concepts such as democracy, power and autonomy. Contested concepts like these pose questions: Are terms such as “democracy” hopelessly ambiguous? How can two theorists defend alternative accounts of democracy without talking past each other? How can we understand debates in which theorists disagree about what democracy is? This paper first discusses the popular strategy to answer these questions by appealing to Rawls’s distinction between concepts and conceptions. According to this approach, defenders of rival conceptions of, e.g. justice can disagree without talking past each other because they share the concept of justice. It is argued that this idea is attractive but limited in application and that it fails to do justice to the dynamic and normative aspects of concept formation. Reflective equilibrium is then suggested as an alternative approach. It replaces the static contrast between a conceptual ‘core’ and competing conceptions by a dynamic perspective of concept formation as a partly normative undertaking: pre-theoretic language use and commitments can provide a shared starting point for developing alternative accounts which yield different concepts of, e.g. justice. This perspective provides a new understanding of how it is possible that different theorists defend rival accounts of, e.g. justice, without talking past each other.


Tanja Rechnitzer. 2022. Applying Reflective Equilibrium. Towards the Justification of a Precautionary Principle. Springer.


Technical reports:



Selected theses by students:

Noah Werder. 2023. Debatten mit einem RE-Modell besser verstehen. Eine explorative Anwendung des formalen RE-Modells von Beisbart, Betz und Brun. (BA thesis)

Alexander Koch. 2022. A Robust Model for the Reflective Equilibrium of Goodman and Rawls (MA thesis)

Sebastian Flick. 2022. Ein realistischeres Modell des Überlegungsgleichgewichts (BA thesis)