 That was to remain the situation for almost another fifteen years, until John Bell utilized the EPRB set-up to construct a stunning argument, at least as challenging as EPR, but to a different conclusion (Bell 1964). Bell considers correlations between measurement outcomes for systems in separate wings where the measurement axes of the systems differ by angles set locally. In his original paper, essentially using the lemma from EPR governing strict correlations, Bell shows that correlations measured in different runs of an EPRB experiment satisfy a system of constraints, known as the Bell inequalities. Later demonstrations by Bell and others, using related assumptions, extend this class of inequalities. In certain of these EPRB experiments, however, quantum theory predicts correlations that violate particular Bell inequalities by an experimentally significant amount. Thus Bell shows (see the entry on  Bell’s Theorem)  that the quantum statistics are inconsistent with the given assumptions. Prominent among these is an assumption of locality, similar to the locality assumptions tacitly assumed in EPR and (explicitly) in the one-variable and many-variable arguments of Einstein. One important difference is that for Einstein locality restricts factors that might influence the (assumed) real physical states of spatially separated systems (separability). For Bell, locality is focused instead on factors that might influence outcomes of measurements in experiments where both systems are measured. (See Fine 1996, Chapter 4.) These differences are not usually attended to and Bell’s theorem is often characterized simply as showing that quantum theory is nonlocal. Even so, since assumptions other then locality are needed in any derivation of the Bell inequalities (roughly, assumptions guaranteeing a classical representation of the quantum probabilities; see Fine 1982a, and Malley 2004), one should be cautious about singling out locality (in Bell’s sense, or Einstein’s) as necessarily in conflict with the quantum theory, or refuted by experiment.