> This makes total sense if it's actually a wave and the particle is merely a solution for a particular world W. The detector didn't change anything about the wave. It just coupled you to the wave system earlier, so now your branch of the many-world tree can only see the subset of solutions that correspond with whatever you detected. The only thing that has changed, though, is your ability to see the other solutions. You branched earlier, so now each branch you exist in only sees a subset of the full solution.
This explanation only works if either the detector is not itself made of particles, or if there is a detector wave that you could become entangled with by observing.
But the first one can essentially be discarded, and the second one is not experimentally confirmed. The equations happen the way I described whether you observe the detector or not. The detector could be hundreds of light years away from you, but you would still be able to predict what happened after the particle hit it with classical mechanics. So one particle's interaction with a detector instantly branches at least its entire future light-cone, but two particles interacting doesn't have the same effect. So at what scale does this happen? Or in what conditions?
This explanation only works if either the detector is not itself made of particles, or if there is a detector wave that you could become entangled with by observing.
But the first one can essentially be discarded, and the second one is not experimentally confirmed. The equations happen the way I described whether you observe the detector or not. The detector could be hundreds of light years away from you, but you would still be able to predict what happened after the particle hit it with classical mechanics. So one particle's interaction with a detector instantly branches at least its entire future light-cone, but two particles interacting doesn't have the same effect. So at what scale does this happen? Or in what conditions?