Underdetermination: A Realist Interpretation of Quantum Mechanics and Bohmian Mechanics

James T. Cushing

Darrin W.S. Belousek

A. Matzkin, Nvrock

The de Broglie-Bohm interpretation of quantum mechanics (BM) has been favored as the preferred alternative to standard quantum mechanics on the ground that it allows a realist construal of the quantum world. We examine in the present work whether BM is consistent with scientific realism. Indeed, Bohmian mechanics makes strong ontological claims but accepts in principle the impossibility of generating epistemic warrants in support of its assumptions. We will argue that such a situation gives rise, at best, to an unsolvable underdetermination dilemma. This leads in turn to the following paradox: although Bohmian mechanics has frequently been invoked to reconcile quantum mechanics with realism, its status as a valid interpretation of quantum mechanics hinges nonetheless on nonevidential epistemological arguments traditionally associated with antirealism.

Dennis Dieks

James D. Fraser, Peter Vickers

The existence of multiple interpretations of quantum mechanics appears to pose a serious challenge for knowledge claims about the quantum domain. Hoefer argues that a scientific realist epistemology must be abandoned in this context, while Callender 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 that all the major ontic interpretations of quantum mechanics agree on. It is commonly believed that Everettian, Bohmian, and GRW (Ghirardi–Rimini–Weber) 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.

Bradford Skow

Bohmian mechanics faces an underdetermination problem: when it comes to solving the measurement problem, alternatives to the Bohmian guidance equation work just as well as the official guidance equation. Dürr, Goldstein, and Zanghì have argued that of the candidate guidance equations, the official guidance equation is the simplest Galilean‐invariant candidate. This symmetry argument—if it worked—would solve the underdetermination problem. But the argument does not work. It fails because it rests on assumptions about how Galilean transformations (especially boosts) act on the wavefunction that are (in this context) unwarranted. My discussion has larger morals about the physical significance of certain mathematical results (like, for example, Wigner’s theorem) in non‐orthodox interpretations of quantum mechanics.