On Mon, Feb 3, 2014 at 6:29 PM, LizR <lizj...@gmail.com> wrote: > On 4 February 2014 12:23, Jesse Mazer <laserma...@gmail.com> wrote: > >> On Mon, Feb 3, 2014 at 5:48 PM, <ghib...@gmail.com> wrote: >> >>> >>> But more generically speaking, would this inference for blocktime sit at >>> the edge of relativity or at its core. What I mean is, beyond that it is an >>> implication of relativity, have there been or are there any prospects for >>> developing blocktime as it arises from relativity to such point, >>> predictions get made? Or any other kind of reinforcement? Or does blocktime >>> go on to imply something beyond blocktime? >>> >> >> If "block time" is taken as a definite ontological statement about all >> times "existing" in exactly the same sense, rather than just referring to >> the idea of treating time as a dimension conceptually or in our >> mathematical models, then I think it's a metaphysical postulate that goes >> beyond anything directly implied by relativity. Relativity says that all >> frames, with their different definitions of simultaneity, are on equal >> footing as far as the laws of physics are concerned, but it doesn't deal >> with ontology. If someone proposes that one frame's definition of >> simultaneity is "metaphysically preferred" in the sense it defines the >> "true present", but adds the caveat that this frame is not in any way >> physically preferred so that no conceivable experiment could determine >> which frame it is, this wouldn't contradict the physics. It would be an >> "interpretation" of SR, similar to the different "interpretations" of QM >> which postulate different things about ontology (the real existence of >> other worlds in the MWI, or a single world with hidden variables in Bohmian >> mechanics, for example) but are indistinguishable experimentally. >> > > SR directly demonstrates block time via the relativity of simultaneity. > This can be tested experimentally. >
The relativity of simultaneity is a claim about physics, not metaphysics. Specifically, it's a claim that the laws of physics work exactly the same in all inertial frames, which have different definitions of simultaneity. If someone agrees that no frame's definition of simultaneity is "preferred" in any physical sense, but that one is "metaphysically preferred" in a way that is wholly invisible to all possible experiments, this would not contradict SR or the relativity of simultaneity as a physical principle. > >> That said, if you subscribe to any form of Occam's razor or even a >> criteria of "elegance" when it comes to choosing between different >> metaphysical hypotheses, it seems a lot simpler to assume that there is no >> metaphysically preferred definition of simultaneity, just as I think many >> would agree the MWI is the simplest way of interpreting the physical theory >> of QM. Adding extra "purely metaphysical" entities to a theory, which don't >> correspond to anything that appears in the mathematical formalism of the >> theory itself (which would apply to things like a "true present" or to >> hidden variables in QM), seems a bit like postulating that there are >> invisible intangible elves sitting on each person's head which have no >> causal effects on anything we can measure; sure it's logically possible, >> but it seems like a very inelegant and arbitrary way for reality to work. >> >> The MWI is deterministic, however, and hence has hidden variables. > No. The Schroedinger equation which calculates wavefunction evolution in QM is already fully deterministic, the MWI just dispenses with the extra postulate of "wavefunction collapse" on measurement, which is the only random element in QM. Determinism only implies hidden variables if you assume each experiment has a *unique* outcome, and that this outcome is generated in a deterministic way by the initial conditions. If you assume that the physical state at the end of an experiment is a quantum state that's a superposition of many possible classical results, then this can be calculated from a prior quantum state using just the standard Schroedinger equation. Jesse -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
