> "From the point of view of the friend, the measurement result was determined long before Wigner had asked about it, and the state of the physical system has already collapsed. When now exactly did the collapse occur? Was it when the friend had finished their measurement, or when the information of its result entered Wigner's consciousness?"
This to me, shows just how hand-wavy the whole superposition/quantum collapse stuff really is. I have to say I side with Einstein with his view that everything is already in one state or the other. We don't cause the system to choose a state when we measure it. We simply discover the state it was already in. It is one thing to assign a probability to which state we will find it in. It is quite another to create an entire theory around quantum measurement.
There is nothing mysterious about this paradox. The friend performs the measurement ans discovers the state of the particle/system. Wiger doesn't know about it, but that doesn't mean it's not in that state, he just isn't aware of it yet. The fact this is a paradox just seems like silly mind games.
> "From the point of view of the friend, the measurement result was determined long before Wigner had asked about it, and the state of the physical system has already collapsed. When now exactly did the collapse occur? Was it when the friend had finished their measurement, or when the information of its result entered Wigner's consciousness?"
This to me, shows just how hand-wavy the whole superposition/quantum collapse stuff really is. I have to say I side with Einstein with his view that everything is already in one state or the other. We don't cause the system to choose a state when we measure it. We simply discover the state it was already in. It is one thing to assign a probability to which state we will find it in. It is quite another to create an entire theory around quantum measurement.
There is nothing mysterious about this paradox. The friend performs the measurement ans discovers the state of the particle/system. Wiger doesn't know about it, but that doesn't mean it's not in that state, he just isn't aware of it yet. The fact this is a paradox just seems like silly mind games.