Quantum Probabilities & Objectivity: New Pragmatist Insights – QUOPROB

The project investigates the foundations of the “operational” approach to quantum probabilities. Though the effectiveness of this approach is widely acknowledged by physicists, much less consensus exists about its logical consistency – whence the low popularity of Bohr-inspired instrumentalist interpretations of quantum mechanics among philosophers. Our project will pursue various pragmatist lines of inquiry in contemporary epistemology and philosophy of language in order to verify whether it is possible to devise an “operational” probabilistic semantics which can avoid the pitfalls of the so-called measurement problem while in no way implying “subjectivism”. More specifically, we propose to reformulate the operational reconstruction of quantum mechanics as a transcendental argument within the framework of a generalized inferentialist theory of meaning – a framework in which the normative aspects of the constitutive process of objectivity are especially emphasized. We will address the question of whether (in which sense, to which extent) the structural features of quantum mechanics can be taken to express the conceptual presuppositions of empirical knowledge. And we will extend this analysis to a large class of generalized probability theories, which contains quantum mechanics as a particular case, examining the epistemological status of the restrictive axioms which select standard quantum mechanics out of more general formal schemes. While our project explicitly addresses issues relating to the foundations of quantum mechanics as well as possible theoretical developments of the theory, we nonetheless expect that the critical analysis of the conditions under which the proposed approach can be taken to dissolve the interpretive puzzles of quantum mechanics will provide an original contribution to the current debate on inferentialist (vs “representational”) semantics, especially in so far as epistemological implications (relating in particular to the status of logic) are at stake. The project is a cooperation between Michel Bitbol (a philosopher of knowledge based at the Husserl Archives of the Ecole Normale Supérieure of Paris) and Caslav Brukner (a theoretical physicist based at the Institute for Quantum Optics and Quantum Information of the Österreichische Akademie der Wissenschaften of Vienna). It combines various methodological approaches, including mathematical techniques from the study of quantum information, epistemological reflections inspired by the Kantian and Wittgensteinian traditions, and pragmatist theories of meaning as developed in contemporary analytic philosophy.