 If \(J\) measures a system that is determinately \(x\)-spin up, then \(J\) will determinately record “\(x\)-spin up”; and if \(J\) measures a system that is determinately \(x\)-spin down, then \(J\) will determinately record “\(x\)-spin down” (and we assume, for simplicity, that the spin of the object system \(S\) is undisturbed by the interaction). 