Could you elaborate on that? I have hard time believing it without a reference. Edit: Probably you were referring to the need for "wavefunction collapse" in th

Could you elaborate on that? I have hard time believing it without a reference. Edit: Probably you were referring to the need for "wavefunction collapse" in the Copenhagen theory. Practically, this can be addressed with the Master equations (or other approaches) for open quantum systems. Philosophically it might be unpleasant, but mathematically it is no different from what the Many World/Multiverse requires.