Post #3124422

2026-03-20 19:36 UTC

@androcat@toot.cat I guess I'd roughly think of interpretations of quantum mechanics (IQMs) as marrying a certain ontology to the math and observed behavior of quantum mechanics (QM). So it's definitely true that these can rule in or out certain statements about ontology, but they always have some story for how it still matches up with the math and observations. I'd also point out that while we can expect there to be many IQMs that are consistent with the math and observations of QM, I think it is possible to have an IQM that you discover is actually inconsistent with some of these fixed aspects of QM. The simplest example of these would seem to be pilot wave theory, which in its most rudimentary form is not, so far as I know, consistent with relativity. So while it does match non-relativistic QM (which makes it quite interesting), it does not extend to relativistic QM (though I gather that there are extensions or modifications of pilot wave theory that purport to). @dougmerritt@mathstodon.xyz @davidsuculum@mathstodon.xyz

Replies (3)

@internic@mathstodon.xyz 2026-03-20 19:44

@androcat@toot.cat But I honestly view a certain version of the "orthodox" IQM this way, as being demonstrably wrong. By this I mean the view that macroscopic measuring apparatuses interacting with microscopic quantum systems induce a non-deterministic, irreversible state reduction, a change in the actual state of the system rather than just our knowledge of or belief about the system. There are, of course, many adherents of the "Copenhagen interpretation" who would say they don't take this view, but in my experience this is exactly how many working physicists view it. This is definitively incorrect, because it's inconsistent (without additional ingredients): macroscopic systems comprise many microscopic quantum systems, and a collection of quantum systems still obeys QM, with deterministic, reversible dynamics. This is precisely why when I want to think carefully about any subtle aspect of quantum measurement I turn to MWI, since it at least seems to present a self-consistent way to understand what's going on*. Granted, for most practical purposes thinking in the (ultimately incorrect) way outlined above works just fine. * This is not to say MWI is the only self-consistent IQM, it's just the one I'm most familiar with, outside of the spectrum one might refer to as "orthodox" or Copenhagen interpretation. @dougmerritt@mathstodon.xyz @davidsuculum@mathstodon.xyz

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@davidsuculum@mathstodon.xyz 2026-03-20 21:04

@internic@mathstodon.xyz @androcat@toot.cat @dougmerritt@mathstodon.xyz I think, but I'm speaking from memory, that some interpretations called spontaneous collapse can be tested, and that indeed the evidence seemed to be slightly against them. But again, speaking from memory only.

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@androcat@toot.cat 2026-03-23 07:57

@internic@mathstodon.xyz @dougmerritt@mathstodon.xyz @davidsuculum@mathstodon.xyz The way I understand it, if an interpretation is found to conflict with the observable, it immediately gets changed until it fits it again (a bit like religious beliefs in that sense). Sometimes these changes mean it loses proponents, but not always.

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