Bohm's approach and Individuality

TL;DR

This paper defends the Bohm theory as a genuine interpretation of quantum particles as individuals, discusses its limitations and modifications, and explores its mathematical and philosophical implications related to holism and structural realism.

Contribution

It clarifies that Brown et al.'s research does not dismiss Bohm theory's individuality, analyzes modifications to BT, and connects it to symplectic geometry and implicate order concepts.

Findings

Bohm theory can be interpreted as describing quantum particles as individuals.

Modified Bohm theory emphasizes the holistic and context-dependent nature of particles.

Bohm's implicate order shares similarities with structural realism.

Abstract

Ladyman and Ross (LR) argue that quantum objects are not individuals (or are at most weakly discernible individuals) and use this idea to ground their metaphysical view, ontic structural realism, according to which relational structures are primary to things. LR acknowledge that there is a version of quantum theory, namely the Bohm theory (BT), according to which particles do have definite trajectories at all times. However, LR interpret the research by Brown {\em et al.} as implying that "raw stuff" or {\em haecceities} are needed for the individuality of particles of BT, and LR dismiss this as idle metaphysics. In this paper we note that Brown {\em et al.}'s research does not imply that {\em haecceities} are needed. Thus BT remains as a genuine option for those who seek to understand quantum particles as individuals. However, we go on to discuss some problems with BT which led Bohm and Hiley to modify it. This modified version underlines that, due to features such as context-dependence and non-locality, Bohmian particles have a very limited autonomy in situations where quantum effects are non-negligible. So while BT restores the possibility of quantum individuals, it also underlines the primacy of the whole over the autonomy of the parts. The later sections of the paper also examine the Bohm theory in the general mathematical context of symplectic geometry. This provides yet another way of understanding the subtle, holistic and dynamic nature of Bohmian individuals. We finally briefly consider Bohm's other main line of research, the "implicate order", which is in some ways similar to LR's structural realism.