 According to Bell’s theorem (Bell 1964; Clauser et al. 1969; see also the entry on  Bell’s theorem)  and its descendants (e.g., Greenberger, Horne, &amp; Zeilinger 1989; see also Goldstein et al. 2011; Brunner et al. 2014 for an overview), any theory that reproduces all the correlations of measurement outcomes predicted by quantum theory must violate a principle that Bell calls local causality (Bell 1976, 1990; see also Norsen 2011; Wiseman &amp; Cavalcanti 2017). In a locally causal theory, probabilities of spatiotemporally localized events occurring in some region 1 are independent of what occurs in a region 2 that is spacelike separated from region 1, given a complete specification of what occurs in a spacetime region 3 in region 1’s backward light cone that completely shields off region 1 from the backward light cone of region 2. (See, for instance, Figs. 4 and 6 in Bell 1990 or Fig. 2 in Goldstein et al. 2011.)