Abstract

Part 1 (a fortnight ago) introduced stochastic Einstein locality (SEL), which is a version of the idea of relativistic causality, i.e. the idea that influences propagate at most as fast as light. SEL is similar to Reichenbach’s Principle of the Common Cause (PCC), and Bell’s Local Causality. We also discussed formulations of SEL for a fixed background spacetime.

In this Part Two, I will review this material (so having heard Part One is not necessary!). Then I will argue that SEL is violated by the outcome dependence shown by Bell correlations, both in quantum mechanics and in quantum field theory. It needs arguing, in the light of some recent literature which argues that outcome dependence does not violate the PCC .

Finally, I briefly discuss how to formulate relativistic causality if there is no fixed background spacetime. I will describe Kent’s 2005 proposed experiment, and the formulations of SEL in causal sets of the sort studied by Sorkin, Dowker, Brightwell, Rideout Henson et al.