Eliezer asked (of zigzag theories): “One measurement has to change the other, so which measurement happens first?”
It doesn’t have to be that way. Events can be determined through a combination of local causality and global consistency; see the work on attempts to create time travel paradoxes using wormholes. For example, you may set things up so that a sphere, sent into one end of a wormhole, should emerge from the other in such a way as to collide with itself on the way in, thereby preventing its entry. It sounds like a grandfather paradox: what’s the answer? The answer is that only nonparadoxical histories are even possible; such as those in which the sphere emerges and perturbs its prior course, but not by so much as to prevent its entry into the wormhole.
The harmony of distant outcomes in an EPR experiment may similarly be due to a global consistency.
Ideally, in order to apply the description-length version of Occam’s razor to competing and wildly dissimilar theories, such as we have in these attempts to explain quantum mechanics, one would first take the rival theories, embed them in a common superfamily of possible theories, deploy some prior across that superfamily, and then condition on experimental results. However, neither many worlds nor temporal zigzag is even capable of reproducing experimental results, so long as they cannot derive the Born probabilities. There are two types of realist theories which are experimentally adequate: stochastic objective collapse theories (e.g. Ghirardi-Rimini-Weber), and deterministic nonlocal hidden-variable theories (e.g. Bohm). In theory, if we’re trying to figure out our best current guess, we have to choose between those two! In practice, it seems obvious that theoretical pluralism is still called for, and that much more work needs to be done by the advocates of interpretations which remain qualitative but could become quantitative.
Eliezer asked (of zigzag theories): “One measurement has to change the other, so which measurement happens first?”
It doesn’t have to be that way. Events can be determined through a combination of local causality and global consistency; see the work on attempts to create time travel paradoxes using wormholes. For example, you may set things up so that a sphere, sent into one end of a wormhole, should emerge from the other in such a way as to collide with itself on the way in, thereby preventing its entry. It sounds like a grandfather paradox: what’s the answer? The answer is that only nonparadoxical histories are even possible; such as those in which the sphere emerges and perturbs its prior course, but not by so much as to prevent its entry into the wormhole.
The harmony of distant outcomes in an EPR experiment may similarly be due to a global consistency.
Ideally, in order to apply the description-length version of Occam’s razor to competing and wildly dissimilar theories, such as we have in these attempts to explain quantum mechanics, one would first take the rival theories, embed them in a common superfamily of possible theories, deploy some prior across that superfamily, and then condition on experimental results. However, neither many worlds nor temporal zigzag is even capable of reproducing experimental results, so long as they cannot derive the Born probabilities. There are two types of realist theories which are experimentally adequate: stochastic objective collapse theories (e.g. Ghirardi-Rimini-Weber), and deterministic nonlocal hidden-variable theories (e.g. Bohm). In theory, if we’re trying to figure out our best current guess, we have to choose between those two! In practice, it seems obvious that theoretical pluralism is still called for, and that much more work needs to be done by the advocates of interpretations which remain qualitative but could become quantitative.