A structuralist reconciliation of the realist and nomological views in Bohmian mechanics

Abstract

This thesis aims to contribute to the discussion of how to interpret the Bohmian ontology. Bohmian Mechanics is a quantum theory that describes the motion of particles, whose trajectories are determined by the quantum wave-function. This theory faces two key questions. The former concerns the metaphysical characterization of the particles; the latter relates to the ontological status of the wave-function. After briefly presenting two possible metaphysical characterizations of the particles, I dedicate the bulk of this work to investigating the status of the wave-function. In particular, I analyse the realist view (which regards the wave-function as a multi-dimensional field) and the nomological view (which considers the wave-function as a law-like entity). My investigation touches upon different levels of inquiry. First, I show that these two ontological interpretations depend on contrasting formulations of the law that dictates the particle motion. Second, I argue that both views defend very problematic ontologies that not only violate familiar metaphysical criteria but also fail to provide a satisfactory explanation of the relation between the particles and the wave-function. Third, I spell out the implicit methodologies that underlie the two views, arguing that they conflate three important categories that should rather be kept separate: the informationally-complete representation of the system, the ontologically-complete representation of the system, and the ontology itself. Finally, I present and advocate structural realism as the metaphysical framework for investigating and understanding the Bohmian ontology. According to the structuralist interpretation, the wave-function represents a network of modal relations whose relata are the particles. I argue that this third view provides the best account of the Bohmian system for three reasons. First of all, it offers a parsimonious ontology that does not create any issue of metaphysical underdetermination. Secondly, it supplies an explanatorily powerful ontology. Thirdly, it relies on a sound methodological program. I conclude with an interesting insight: this structuralist interpretation can be regarded as reconciling the realist view and the nomological view given that it takes on aspects of both views and is compatible with both formulations of the law of motion for the particles.