Knowledge of the Quantum Domain: an Overlap Strategy

Abstract

The existence of multiple interpretations of quantum mechanics appears to pose a serious challenge for knowledge claims about the quantum domain. Hoefer (2020) argues that a scientific realist epistemology must be abandoned in this context, while Callender (2020) argues that the realist’s only option is to break the underdetermination between rival interpretations by appealing to extra-empirical virtues. We develop a different response to the quantum underdetermination problem based on identifying statements about the unobservable which all the major ontic interpretations of quantum mechanics agree on. It is commonly believed that Everettian, Bohmian and GRW quantum mechanics share nothing but empirical content. We argue that, while they say very different things about the fundamental nature of quantum systems, they can be understood as agreeing on a plethora of more abstract theoretical claims. In our view, focusing on this descriptive overlap represents the most promising strategy for defending knowledge claims in the quantum domain. We close by considering how this overlap strategy relates to working posits formulations of scientific realism.