Interpretation Neutrality in the Ontology of Quantum Mechanics

It is widely assumed that the only way to be ontologically serious about quantum mechanics (QM) is to go beyond the standard textbook account and to opt for one of the versions (or interpretations) of QM that were developed in response to the measurement problem. This assumption seems to be confirmed by the observation that recent proposals which seek to remain neutral with respect to such interpretations do not yield a substantive ontology of QM. I will argue against this received wisdom by developing an account that takes standard (“textbook”) QM ontologically seriously, despite its failure to solve the measurement problem. I show that the customary association of quantum ontology with some particular solution to the measurement problem rests on a dubious identification of ontology with fundamental ontology and a concomitant failure to acknowledge the inherently non-fundamental character of QM. After a general defense of my non-fundamentalist approach to ontology, I will demonstrate its viability in some concrete examples of QM. In particular, I will show how an ontologically robust view of some key concepts of textbook QM (spin, wave function collapse, wave packets) does not depend on choosing a particular response to the measurement problem. Finally, I will reply to two possible objections: first, that the ontological posits of my proposal aren’t local beables, and second, that my account only purchases what looks like an ontological commitment at the price of semantic vagueness