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> the primary motivation for MWI is to solve the Schrödinger's cat paradox, and that this is its only advantage. This is, of course, completely wrong. By MWI,

> the primary motivation for MWI is to solve the Schrödinger's cat paradox, and that this is its only advantage. This is, of course, completely wrong. By MWI, I am assuming you mean the Many Worlds Interpretation. I am curious: Can you describe what are the other motivations there are for this theory beyond resolving Schrödinger's cat paradox ?

mistercow 13y ago
Sure. To start off, I'd like to point out that Schrödinger's cat really isn't a problem for the Copenhagen interpretation. The hypothetical device is "observing" the system during the entire experiment, so the cat is never in a superposition between dead and alive. At least, I can tell you some of its other advantages. First of all, wavefunction collapse is non-local. That is, if you take the wavefunction as being physically real in some sense, then collapse is an event which propagates faster than the speed of light. Because this cannot be used to actually send information faster than light, it doesn't violate causality. But it still has a smell to it. MWI does not have this problem. Another advantage of MWI is that it is deterministic. Once again, there's no rule that says that physics has to be deterministic. But when you're going along, finding one deterministic law after another, and then all of a sudden it seems that things are non-deterministic after all, it should give you pause. There are other problems MWI solves which I don't understand as well, most dealing with problems with wavefunction collapse. In short, collapse has a lot of properties which are highly suspicious because you just don't see them elsewhere in physics. It's also arguably a simpler interpretation, in which case Occam's razor applies. Unfortunately, we don't yet have good ways of estimating the algorithmic complexity of arbitrary hypotheses, so whether this is actually the case is a matter of debate.

mistercow 13y ago

Sure. To start off, I'd like to point out that Schrödinger's cat really isn't a problem for the Copenhagen interpretation. The hypothetical device is "observing" the system during the entire experiment, so the cat is never in a superposition between dead and alive. At least, I can tell you some of its other advantages. First of all, wavefunction collapse is non-local. That is, if you take the wavefunction as being physically real in some sense, then collapse is an event which propagates faster than the speed of light. Because this cannot be used to actually send information faster than light, it doesn't violate causality. But it still has a smell to it. MWI does not have this problem. Another advantage of MWI is that it is deterministic. Once again, there's no rule that says that physics has to be deterministic. But when you're going along, finding one deterministic law after another, and then all of a sudden it seems that things are non-deterministic after all, it should give you pause. There are other problems MWI solves which I don't understand as well, most dealing with problems with wavefunction collapse. In short, collapse has a lot of properties which are highly suspicious because you just don't see them elsewhere in physics. It's also arguably a simpler interpretation, in which case Occam's razor applies. Unfortunately, we don't yet have good ways of estimating the algorithmic complexity of arbitrary hypotheses, so whether this is actually the case is a matter of debate.