 On the standard eigenvalue-eigenstate link (rule 3) \(\boldsymbol{E}\) is not a state where \(J\) determinately records “spin up”, neither is it a state where \(J\) determinately records “spin down”. So Everett’s interpretational problem is to explain the sense in which \(J\)’s entangled superposition of mutually incompatible records represents a determinate measurement outcome that agrees with the empirical prediction made by the standard collapse formulation of quantum mechanics when the standard theory predicts that \(J\) either ends up with the fully determinate measurement record “spin up” or the fully determinate record “spin down”, with probabilities equal to \(a\)-squared and \(b\)-squared respectively. More specifically, here the standard collapse theory predicts that on measurement the quantum-mechanical state of the composite system will collapse to precisely one of the following two states: 