Philosophy of Physics Graduate Lunch Seminar (Monday - Week 6, HT20)
The talk analyses and develops on Bell’s (1987) proposed variant of the Everett interpretation, hitherto understudied or hastily dismissed in the literature. The resulting theory is about the holistic system, comprised of –but not necessarily reducible to – all particles in the universe, each located in ordinary, 3-dimensional space. This many-particle system as a whole performs random jumps through 3N-dimensional configuration space. The distribution of its spontaneous localisations in configuration space is given by the Born Rule probability measure for the universal wavefunction. Contra Bell, the theory is argued to be a minimally Bohmian theory – hence dubbed “Minimal Bohmian Mechanics” (MBM) – within the Primitive Ontology framework (for which I offer a metaphysically more perspicuous formulation than is customary). MBM’s formalism is that of ordinary Bohmian Mechanics (BM), without the postulate of continuous particle trajectories and their deterministic dynamics. This “rump formalism” receives, however, a different interpretation. Rebutting objections voiced by Bell and Maudlin, I defend MBM as an empirically adequate and coherent quantum theory. The “for all practical purposes”-classical, Everettian worlds (i.e. quasi-classical histories) exist sequentially in MBM (rather than simultaneously, as in the Everett interpretation). In a temporally coarse-grained sense, they quasi-persist. By contrast, the individual particles themselves cease to persist. MBM, we propound, poses a serious challenge to its orthodox, deterministic cousin, especially in light of the latter’s empirically underdetermined dynamics.