I think that's a mischaracterization of the Copenhagen Interpretation. It would be more correct to say that (according to the CI) a particle's properties don't exist before they're measured.
Which one strikes you as requiring more black magic?
Neither. The nonlocality itself is the black magic, in my mind. There's a retroactivity about it, if you will, and that's what leads to all the counterintuitive shenanigans of objects at the quantum scale.
Physicist(#39) I think that's a mischaracterization of the Copenhagen Interpretation. It would be more correct to say that (according to the CI) a particle's properties don't exist before they're measured. .
Quantum mechanics tells us what we can know about a particle. To say that it does not exist before it is measured is saying that we can make no meaningful statement about its properties. Doing a sum over the history of a particle does not mean that the particle took all possible paths from point A to point B, it means that it is not possible to say which way it went. In this sense, the particle took all possible paths, but that is not physically possible. So one can say that it had no meaningful existence between points A and B.
Either way, we are limited in what we can know, not necessarily what is “real”.
Another example, outside of QM:
If other universes exist, by definition, they cannot communicate with our universe. It what sense can these universes be said to exist if it is impossible to detect them?