Local Causality and Completeness: Bell vs. Jarrett

TL;DR

This paper clarifies the concept of local causality in Bell's theorem by contrasting Bell's original understanding with Jarrett's interpretation, revealing a crucial difference that impacts the interpretation of quantum nonlocality.

Contribution

It provides a detailed analysis of the differences between Bell's and Jarrett's understanding of local causality, clarifying misconceptions in the interpretation of Bell's theorem.

Findings

Identifies a crucial difference between Bell's and Jarrett's definitions of local causality.

Shows that misconceptions about Bell's understanding have influenced interpretations of quantum nonlocality.

Clarifies the conceptual foundations of Bell's theorem in relation to local causality.

Abstract

J.S. Bell believed that his famous theorem entailed a deep and troubling conflict between the empirically verified predictions of quantum theory and the notion of local causality that is motivated by relativity theory. Yet many physicists continue to accept, usually on the reports of textbook writers and other commentators, that Bell's own view was wrong, and that, in fact, the theorem only brings out a conflict with determinism or the hidden-variables program or realism or some other such principle that (unlike local causality), allegedly, nobody should have believed anyway. (Moreover, typically such beliefs arise without the person in question even being aware that the view they are accepting differs so radically from Bell's own.) Here we try to shed some light on the situation by focusing on the concept of local causality that is the heart of Bell's theorem, and, in particular, by contrasting Bell's own understanding with the analysis of Jon Jarrett which has been the most influential source, in recent decades, for the kinds of claims mentioned previously. We point out a crucial difference between Jarrett's and Bell's own understanding of Bell's formulation of local causality, which turns out to be the basis for the erroneous claim, made by Jarrett and many others, that Bell misunderstood the implications of his own theorem.