chosen component of $\mathbf{\sigma }_{2}$ \[in the Bohm-EPR scenario\], by previously measuring the same component of $\mathbf{\sigma }_{1}$, it follows that the result of any such measurement must actually be predetermined. (*op. cit.*, p. 15)

Afterwards he repeatedly stressed that any theory proposed as an attempt to complete quantum theory while restoring locality and causality need not be *assumed* to be deterministic: to recover such perfect (anti)correlations it would *have* to be deterministic. This argument warrants closer examination, and I’ll come back to it. But in later work Bell offered formulations of locality conditions tailored to theories that were not deterministic.

An initial motivation may have been to facilitate experimental tests of attempted local, causal completions of quantum mechanics by suitable measurements of spin or polarization components on pairs of separated systems represented by entangled quantum states. Inevitable apparatus imperfections would make it impossible to confirm a quantum prediction of perfect (anti)correlation for matched components, so experiment alone could not require a local, causal theory to reproduce them. Einstein himself thought some theory might come to underlie quantum mechanics much as statistical mechanics underlies thermodynamics. In each case there would be circumstances in which the more basic theory (correctly) predicts 