there is another argument speaking for many-worlds (indeed, even for all possible worlds—which raises new interesting questions of what is possible of course—certainly not everything that is imaginable): that to specify one universe with many random events requires lots of information, while if everything exists the information content is zero—which fits nicely with ex nihilo nihil fit :-)
Structure and concreteness only emerges from the inside view, which gives the picture of a single world. Max Tegmark has paraphrased this idea nicely with the quip “many words or many worlds” (words standing for high information content).
But MWI is not the doctrine ‘everything exists’. This is a change of topic. Yes, if we live in a Tegmark universe and MWI is the simplest theory, then it’s likely we live in one of the MWI-following parts of the universe. But if we don’t live in a Tegmark universe and MWI is the simplest theory, then it’s still likely we live in one of the MWI-following possible worlds. It seems to me that all the work is being done by Ockham, not by Tegmark.
Max Tegmark has paraphrased this idea nicely with the quip “many words or many worlds”
Sure, but why is the information content of the current state of the universe something that we would want to minimize? In both many-worlds and alternatives, the complexity of the ALGORITHM is roughly the same.
there is another argument speaking for many-worlds (indeed, even for all possible worlds—which raises new interesting questions of what is possible of course—certainly not everything that is imaginable): that to specify one universe with many random events requires lots of information, while if everything exists the information content is zero—which fits nicely with ex nihilo nihil fit
Now THAT’s an interesting argument for MWI. It’s not a final nail in the coffin for de Broglie-Bohm, but the naturalness of this property is certainly compelling.
Although Tegmark incidentally endorses MWI, Tegmark’s MUH does not entail MWI. Yes, if there’s a model of MWI, then some world follows MWI; but our world can be a part of a MUH ensemble without being in an MWI-bound region of the ensemble. We may be in a Bohmian portion of the ensemble.
Tegmark does seem to think MWI provides some evidence for MUH (which would mean that MUH predicts MWI over BM), but I think the evidence is negligible at best. The reasons to think MWI is true barely overlap at all with the reasons to think MUH is. In fact, the failure of Ockham to resolve BM v. MW could well provide evidence against MUH; if MWI (say) turned out to be substantially more complex (in a way that gives it fewer models) and yet true, that would give strong anthropic evidence against MUH. MUH is more plausible if we live in the kind of world that should predominate in the habitable zone of an ensemble.
Mitchell,
there is another argument speaking for many-worlds (indeed, even for all possible worlds—which raises new interesting questions of what is possible of course—certainly not everything that is imaginable): that to specify one universe with many random events requires lots of information, while if everything exists the information content is zero—which fits nicely with ex nihilo nihil fit :-)
Structure and concreteness only emerges from the inside view, which gives the picture of a single world. Max Tegmark has paraphrased this idea nicely with the quip “many words or many worlds” (words standing for high information content).
Max’s paper is quite illuminating: Tegmark, Max. 2007. The Mathematical Universe http://arxiv.org/abs/0704.0646
So we could say that there a good metaphysical reasons for preferring MWI to GRW or Bohm.
But MWI is not the doctrine ‘everything exists’. This is a change of topic. Yes, if we live in a Tegmark universe and MWI is the simplest theory, then it’s likely we live in one of the MWI-following parts of the universe. But if we don’t live in a Tegmark universe and MWI is the simplest theory, then it’s still likely we live in one of the MWI-following possible worlds. It seems to me that all the work is being done by Ockham, not by Tegmark.
Sure, but why is the information content of the current state of the universe something that we would want to minimize? In both many-worlds and alternatives, the complexity of the ALGORITHM is roughly the same.
Now THAT’s an interesting argument for MWI. It’s not a final nail in the coffin for de Broglie-Bohm, but the naturalness of this property is certainly compelling.
Although Tegmark incidentally endorses MWI, Tegmark’s MUH does not entail MWI. Yes, if there’s a model of MWI, then some world follows MWI; but our world can be a part of a MUH ensemble without being in an MWI-bound region of the ensemble. We may be in a Bohmian portion of the ensemble.
Tegmark does seem to think MWI provides some evidence for MUH (which would mean that MUH predicts MWI over BM), but I think the evidence is negligible at best. The reasons to think MWI is true barely overlap at all with the reasons to think MUH is. In fact, the failure of Ockham to resolve BM v. MW could well provide evidence against MUH; if MWI (say) turned out to be substantially more complex (in a way that gives it fewer models) and yet true, that would give strong anthropic evidence against MUH. MUH is more plausible if we live in the kind of world that should predominate in the habitable zone of an ensemble.