  Cabello (2002), using a very similar reasoning, has shown that the MKC models lead to predictions that testably differ from the ones of QM. For DCK, he effectively uses the strategy sketched above: QM gives probabilities for directions in the Clifton-Kent set which their model must match in order to reproduce QM predictions. As these directions are arbitrarily close to directions from a KS-uncolourable set (or directions leading to Clifton’s constraint), this leads to restrictions for these nearby points that are measurably violated by the QM predictions. For Meyer’s DM Cabello’s case is even stronger. He explicitly presents a set of nine rational vectors leading to predictions different from QM (for three of these directions). Hence, the Meyer argument is effectively rebutted (without recourse to Mermin’s requirement): Even if there were only observables corresponding to the rational directions in R3 (which in itself is an implausible assumption) a theory assuming that they all have noncontextual values faithfully revealed by measurement will be measurably at variance with QM. Assume now that the Cabello directions were tested and the QM predictions reliably confirmed, then this would (modulo the reliability of the tests) constitute a proof that Nature is contextual. 