Bohm’s Approach and Individuality

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. This chapter draws attention to a version of quantum theory, namely the Bohm theory (BT), according to which particles do have definite trajectories at all times. This would suggest that quantum particles are individuals after all, with position being the property in virtue of which particles are always different from one another. LR dismiss this possibility because they think that the individuality of particles of BT requires haecceities. Following Brown et al., this chapter suggests that this need not be the case. However, it acknowledges that the individuals of BT are very different from those of classical physics. To understand their nature, structuralist considerations are relevant, which suggests an affinity with LR’s views.