The recent revival of conceptual engineering in experimental philosophy is often linked to Rudolf Carnap. To highlight some key discrepancies between this contemporary approach and Carnap’s original vision, I focus on the case of reflective equilibrium, as discussed by Brun (2017). From Carnap’s perspective, the integration of explication with reflective equilibrium, as proposed in that paper, may appear to be a promising and theoretically fruitful step toward a more comprehensive method of conceptual re-engineering. The emphasis on theoretical virtues and the recognition of historical and systematic links between the two approaches would likely be welcomed, as would the acknowledgment of concept systems and the move beyond linear processes, which better reflect actual theory development. Nevertheless, several critical concerns would arise. Chief among them is the lack of formal precision in the iterative adjustments of reflective equilibrium. The process of ‘mutual adjustment’ remains too vague and intuitive; clearer rules would be needed to guide and evaluate the process systematically. The method also underplays the transformative power of explication, favoring continuity and similarity over radical conceptual innovation, which could limit progress in theoretical frameworks. The treatment of conceptual systems presents another issue. The combined approach lacks a clear methodology for managing interdependent concepts or coordinating multiple explications. Its non-linear structure, though flexible, introduces uncertainty about the direction and endpoint of the adjustment process. Criteria for achieving equilibrium and resolving competing outcomes remain underdeveloped. Another shortcoming lies in the insufficient attention to background theories. Any method of conceptual revision, from this perspective, must be grounded in an explicit and coherent theoretical framework. Finally, the response to the subject-change challenge appears too cautious, leaning toward preservation rather than embracing explication as a tool for systematic replacement and theoretical advancement. In sum, while the combined method is a valuable contribution, it remains incomplete. Further refinement is needed to enhance formal rigor, emphasize conceptual transformation, and provide clearer strategies for handling complex systems and background commitments – essential steps for a scientifically oriented philosophy. I conclude by examining the extent to which Carnap’s likely objections – viewing the method as incomplete and in need of greater formal rigor, a stronger emphasis on theoretical transformation, and clearer strategies for handling systems of concepts and background theories – might apply more broadly to conceptual re-engineering.
Paweł Kawalec: Full Professor, Department of Epistemology, Faculty of Philosophy, John Paul II Catholic University of Lublin (KUL). Member of the Science of Science Committee of the Polish Academy of Sciences. Publishes on the theory and methodology of science, Bayesian epistemology, argumentation theory and early analytic philosophy. Monographs: Pluralistic Progress in Economics (Routledge 2026, forthcoming), Integral Methodology (2018, in Polish); Causality and Explanation (2006, in Polish) and Structural Reliabilism (2003, Kluwer). Editor and translator of the Polish editions of Carnap’s Der logische Aufbau der Welt (2011) and Logical Foundations of Probability (2024). Editor of over 15 collective volumes in the field of science studies.
