Can a Scientific Realist be Neutral About Interpretations of Quantum Mechanics?

In this paper we develop a strategy for articulating modest realist commitments in the quantum domain without committing to a particular interpretation, based on identifying descriptive overlap between the various realism-compatible interpretations. Contrary to what has sometimes been claimed in the literature, we argue that the overlap between many worlds, hidden variables and spontaneous collapse approaches is not purely empirical, and that it is possible to find non-trivial theoretical claims which are endorsed by all of these interpretations.

We start with an exemplar of the kind of statement we have in mind: “Bound electrons in atoms transition between quantised energy states.” We argue that this statement meets three crucial criteria: (i) It is interpretation neutral. (ii) It doesn’t merely concern “what is observable”. (iii) It is non-trivial in its content concerning an aspect of reality.

We further argue that one can find such statements for various other quantum phenomena, such as scattering, tunnelling, and spin phenomena. The general strategy being employed is to abstract away from the details that are provided within any individual interpretation, employing ‘coarse-grained language’ (taking inspiration from Rosaler 2015). That is, we can say things about ‘spin’, ‘possibility’, ‘collapse’ and so on, whilst refusing to take a stance on deeper ontological questions concerning the precise nature of ‘spin’, ‘possibility’, and ‘collapse’.

A concern arises that our ‘overlap strategy’ and the popular ‘selective realist strategy’ give contradictory results vis-à-vis the theoretical claims warranting a realist commitment: it might turn out that posits which cannot be removed from a particular derivation, and are therefore classed as ‘working posits’ warranting realist commitment according to the selective realist strategy, do not appear in the interpretational overlap, and therefore do not warrant realist commitment according to the overlap strategy. We respond to this concern.