those cases where the post-measurement state has no dependence at all on the pre-measurement state (as in projective measurement of a non-degenerate observable), it seems difficult to avoid the conclusion that this must be the true quantum state of the system—the one it is in—, yet this conclusion is incompatible with a non-ontic reading of quantum states, according to which quantum states *in general* are not states quantum systems are in. Even in those cases where the post-measurement state has a residual dependence on the pre-measurement state, application of the projection postulate imposes strong constraints on the post-measurement state if one assumes that which observable has been measured and which value has been obtained are objective matters. Since such constraints severely restrict admissible state assignments, quantum Bayesians, for the sake of consistency of their subjective Bayesian take on quantum probabilities, feel forced to deny that there can be an objective answer to the question of which observable some measured value is a value of.[^16]

This conclusion, however, is extremely difficult to swallow. If there could be no fact of the matter as to which observable some measured value is a value of according to *all* versions of the epistemic conception 