Brent, The issue I see with a single-world framework is the reliance on possibilities that have no existence or causal link to the realized world. In this view, possibilities are entirely notional, they don’t exist ontologically, and they have no impact on the single realized history. This makes their invocation seem unnecessary, even absurd, because they don’t contribute to the reality we observe in any meaningful way.
If the only thing that exists is the realized world, why appeal to a theoretical ensemble of possibilities? It’s as if the single-world view borrows the language and tools of probability to describe outcomes but discards the explanatory depth provided by an actual ensemble. Without the existence of unrealized possibilities, the concept of "randomness" seems like a placeholder for "it just happened this way," offering no real insight into why this one history unfolded. In contrast, in a multiverse framework, the ensemble is not merely theoretical, it has ontological status. The possibilities exist and have causal relationships within the broader structure. This provides coherence to the use of probability, as it describes the distribution of outcomes across the ensemble, not just within a single, isolated history. The single-world framework effectively asks us to accept a universe where unrealized possibilities are invoked to explain outcomes, yet they have no actual role in shaping reality. This reliance on something that neither exists nor affects the realized world strikes me as deeply incoherent. Quentin Le jeu. 9 janv. 2025, 03:14, Brent Meeker <meekerbr...@gmail.com> a écrit : > > > > On 1/8/2025 4:11 AM, Quentin Anciaux wrote: > > Brent, > > The core of my argument is that in a single-world framework, the ensemble > of possibilities described by Schrödinger’s equation is only conceptual. If > only one history is realized, then those "possibilities" don’t exist in any > meaningful way—they’re theoretical abstractions. In the absence of an > actual ensemble from which a selection occurs, the notion of randomness is > a metaphor, not a mechanism. > > In the many-worlds framework, every possibility is realized, so the > "selection" is an emergent phenomenon from within the structure of the > totality. In the single-world view, however, there’s no actual ensemble. > Probabilities merely describe the likelihood of the one realized outcome, > but there’s no underlying framework where those possibilities are > instantiated. Randomness then becomes a label for the lack of explanation > rather than a true process. > > To say "the single history simply is" and call that random doesn’t resolve > the issue—it just restates it. Without an ensemble that exists > ontologically (even probabilistically), the idea of selection collapses > because there’s nothing to select from. The photon emission you mentioned > is described by probabilities in QM, but those probabilities don’t > correspond to real, alternate outcomes in a single-world framework. The > realized outcome is the only one that exists, and all other "possibilities" > are simply unrealized ideas. > > In contrast, in the many-worlds interpretation, the photon’s emission in > one state is one thread of the total structure, and alternate emissions > exist along other threads. This gives explanatory power to the > probabilities, as they correspond to real structures within the ensemble. > > But small probabilities explain why things *don't* exist. > > > Regarding your point that probabilities lose meaning in MWI because all > possibilities are realized—that’s not the case. Probabilities in MWI are > understood as the measure of the branching structure relative to the > observer's perspective. They still hold meaning because they reflect the > structure of the multiverse, not a singular outcome. > > What about the one's for which P=0, you could as well say that reflect the > structure of the multiverse. Will you make an ensemble of them? > > > The single-world view still strikes me as incoherent because it leans on > the language of probability and possibility but denies their actual > realization. Without an ensemble, it’s hard to see what randomness truly > means. > > In every other application of probability theory (and for years I headed > the Reliability Division at Pt. Mugu) the ensemble is only notional. It is > a the set of possibilities without assuming that they exist, in which case > they would be actualities. With an ensemble of which every member exists, > randomness becomes incoherent. > > Brent > > -- > 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 view this discussion visit > https://groups.google.com/d/msgid/everything-list/207aada7-2a8d-4c9e-8490-a25f23eff83a%40gmail.com > <https://groups.google.com/d/msgid/everything-list/207aada7-2a8d-4c9e-8490-a25f23eff83a%40gmail.com?utm_medium=email&utm_source=footer> > . > -- 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 view this discussion visit https://groups.google.com/d/msgid/everything-list/CAMW2kAoJKWzYSjXeRQJCNBiXo2Xbk8VseggxV%3D6rgWL4y6aMFQ%40mail.gmail.com.
