3 December 2025

3:25 PM – 4:10 PM

Amphi Petit Kursaal

Jacques Dubucs

Jacques Dubucs, a former student of the École Normale Supérieure de Saint-Cloud (1972-1977) and holder of an agrégation in philosophy since 1976, is a French philosopher and logician whose academic and institutional career reflects a constant commitment to research and the structuring of the humanities and social sciences. After a postgraduate thesis in logic (1978) and a doctoral thesis in 1984 on the theory of demonstration, he worked as a senior lecturer in mathematics at the École Normale Supérieure in Rabat from 1980 to 1985, then as a research fellow (1985-1988) and finally as director of research at the CNRS from 1992 onwards. He directed the Institute for the History and Philosophy of Science and Technology (CNRS-Paris I) from 2002 to 2010 and has served on numerous national and European bodies, such as the French National Committee for the History and Philosophy of Science (since 2001), the European Science Foundation, COST and ESFRI, where he chaired the “Social and Cultural Innovation” strategic group (2014-2018). He has also held important administrative positions at the CNRS and the Directorate General for Research (2002-2018), and continues to contribute to research evaluation as a project manager for the High Committee for the Evaluation of Research and Higher Education.

How should we act in borderline cases?

Most concepts are vague, meaning that they admit borderline cases. These are objects or situations where, even with all the available information about them, we cannot decide whether the concepts in question apply to them or not. Logicians have developed formalisms capable of representing these fuzzy concepts, taking into account the fact that introducing a third value, “undetermined,” alongside true and false, fails to address the fact that the notion of a borderline case of a fuzzy concept is itself a fuzzy concept, with borderline cases of its own! It remains to be studied how human action manages to operate in the presence of these fuzzy concepts. At the individual level, the most studied case is that of the “categorical” perception of spoken sounds: certain sub-doxastic mechanisms filter the details of sounds accessible to consciousness and drastically reduce hesitation about the nature of what is heard. At the collective level, the problem is more difficult, since the coordination of action requires agreement on the nature of borderline cases. I will examine a few cases of industrial accidents caused by different understandings of these borderline cases by the agents involved.