regions, perhaps even in such a way that each of them precedes the other in its own rest frame (see [@Zbinden]). In that case there is clearly no non-arbitrary answer to the question as to which measurement occurs first and triggers the abrupt change of state of the other. There exist attempts of overcoming this problem without completely abandoning either collapse or the notion of a quantum state a quantum system is in by making the time-evolution of quantum states dependent on foliations of space-time into sets of parallel hyperplanes, but there does not seem to be general agreement as to whether this programme succeeds, and the approach remains controversial.[^6]

The epistemic conception of quantum states undermines the conceptual presuppositions of the reasoning leading to this problem by rejecting the notion of a quantum state a quantum system is in and by interpreting the assignment of different quantum states to the two systems by different agents as legitimate and very natural: Alice knows about the preparation procedure for the combined two-particle system, and when she registers the result pertaining to her own system this affects her epistemic condition with respect to the second. The state she assigns to it reflects 