:The relevance is that all claims that QM implies real cat states are meterphysical, and not part of the mathematical formulation of QM itself. A “cat state, is the claim that an object really does physically exist in more than one of the states given by the general state vector at the same time. Position is just one representative example for illustrative purposes. The specific experiments being discussed are immaterial. It could be spin, momentum or whatever. E.g for |psy> = |1> +|2>, a cat state claim is a claim that in real physicality that the state |1>  and |2> actually exist simultaneously. QM theory specifically denies that such a measurement can ever be made, therefore such claims should not be implied. A superposition of states should not be interpreted as if such superposition implies a cat can be both dead and alive at the same time. QM rejects that such a concept could ever be proved by an actual measurement, and does not require such a metaphysical interpretation. I can make my self invisible, but only if your back is turned to me sort of thing. There is nothing to source, any credible reference on the postulates of QM states that the result of any measurement must be a single eigenvalue. Its what state vector collapse means! Kevin Aylward