On Friday, September 27, 2019 at 3:23:20 PM UTC-5, Brent wrote: > > > > On 9/27/2019 2:40 AM, Philip Thrift wrote: > > hilip Ball talks about Hossenfelder's take, then Orzel's take: > > > https://philipball.blogspot.com/2019/09/just-how-conceptually-economical-is.html > : > > ... > > *Sabine Hossenfelder*: "Many Worlds in and by itself doesn't say anything > about whether the parallel worlds "exist" because no theory ever does that. > We infer that something exists - in the scientific sense - from > observation. It's a trivial consequence of this that the other worlds do > not exist in the scientific sense. You can postulate them into existence, > but that's an *additional* assumption. As I have pointed out before, saying > that they don't exist is likewise an additional assumption that scientists > shouldn't make. The bottom line is, you can believe in these worlds the > same way that you can believe in God.” > > I have some sympathy with this, but I think I can imagine the Everettian > response, which is to say that in science we infer all kinds of things that > we can’t observe directly, because of their indirect effects that we can > observe. The idea then is that the Many Worlds are inescapably implicit in > the Schrödinger equation, and so we are compelled to accept them if we > observe that the Schrödinger equation works. The only way we’d not be > obliged to accept them is if we had some theory that erases them from the > equation. There are various arguments to be had about that line of > reasoning, but I think perhaps the most compelling is that there are no > other worlds explicitly in any wavefunction ever written. They are simply > an interpretation laid on top. Another, equally tenable, interpretation is > that the wavefunction enumerates possible outcomes of measurement, and is > silent about ontology. In this regard, I totally agree with Sabine: nothing > compels us to believe in Many Worlds, and it is not clear how anything > could ever compel us. > > In fact, *Chad Orzel* suggests > <https://www.forbes.com/sites/chadorzel/2019/09/17/many-worlds-but-too-much-metaphor/> > that > the right way to look at the MWI might be as a mathematical formalism that > makes no claims about reality consisting of multiple worlds – a kind of > quantum book-keeping exercise, a bit like the path integrals of QED. > > > Which is exactly the approach of QBism. > > Brent > > I’m not quite sure what then is gained by looking at it this way relative > to the standard quantum formalism – or indeed how it then differs at all – > but I could probably accept that view. Certainly, there are situations > where one interpretational model can be more useful than others. However, > we have to recognize that many advocates of Many Worlds will have none of > that sort of thing; they insist on multiple separate universes, multiple > copies of “you” and all the rest of it – because their arguments positively > require all that. > > Here, then, is the key point: you are *not* obliged to accept the “other > worlds” of the MWI, but I believe you *are* obliged to reject its claims > to economy of postulates. Anything can look simple and elegant if you sweep > all the complications under the rug. > > > >
On QBism (What did quanta do before the "subjects" of *subjective* probability evolved?): https://arxiv.org/abs/1409.3312 QBism: A Critical Appraisal Ulrich Mohrhoff <https://arxiv.org/search/quant-ph?searchtype=author&query=Mohrhoff%2C+U> (Submitted on 11 Sep 2014) By insisting that the formal apparatus of quantum mechanics is a probability calculus, QBism opens the door to a deeper understanding of what quantum mechanics is trying to tell us. By insisting on a subjectivist Bayesian interpretation of probability in the context of quantum foundations, it closes this door again. To find the proper balance between subject and object, one must turn to Niels Bohr, the alleged "obscurity" of whose views casts a poor light on the current state of foundational research. @philipthrift -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/5bba7c76-0f9e-45f2-b85e-5bad8d770ba8%40googlegroups.com.
