On Saturday, September 14, 2019 at 7:46:27 AM UTC-6, Jason wrote: > > > > On Sat, Sep 14, 2019, 4:36 AM Alan Grayson <agrays...@gmail.com > <javascript:>> wrote: > >> >> >> On Saturday, September 14, 2019 at 12:34:18 AM UTC-6, Jason wrote: >>> >>> >>> >>> On Friday, September 13, 2019, Alan Grayson <agrays...@gmail.com> wrote: >>> >>>> >>>> >>>> On Friday, September 13, 2019 at 4:42:00 PM UTC-6, Jason wrote: >>>>> >>>>> >>>>> >>>>> On Fri, Sep 13, 2019 at 8:25 AM Alan Grayson <agrays...@gmail.com> >>>>> wrote: >>>>> >>>>>> >>>>>> >>>>>> On Friday, September 13, 2019 at 5:24:11 AM UTC-6, Bruno Marchal >>>>>> wrote: >>>>>>> >>>>>>> >>>>>>> On 13 Sep 2019, at 04:26, Alan Grayson <agrays...@gmail.com> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Thursday, September 12, 2019 at 11:01:54 AM UTC-6, Alan Grayson >>>>>>> wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Thursday, September 12, 2019 at 7:45:22 AM UTC-6, Lawrence >>>>>>>> Crowell wrote: >>>>>>>>> >>>>>>>>> On Thursday, September 12, 2019 at 4:20:46 AM UTC-5, Philip Thrift >>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Wednesday, September 11, 2019 at 11:45:41 PM UTC-5, Alan >>>>>>>>>> Grayson wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> https://www.wired.com/story/sean-carroll-thinks-we-all-exist-on-multiple-worlds/ >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Many Worlds is where people go to escape from one world of >>>>>>>>>> quantum-stochastic processes. They are like vampires, but instead of >>>>>>>>>> running away from sunbeams, are running away from probabilities. >>>>>>>>>> >>>>>>>>>> @philipthrift >>>>>>>>>> >>>>>>>>> >>>>>>>>> This assessment is not entirely fair. Carroll and Sebens have a >>>>>>>>> paper on how supposedly the Born rule can be derived from MWI I have >>>>>>>>> yet >>>>>>>>> to read their paper, but given the newsiness of this I might get to >>>>>>>>> it. One >>>>>>>>> advantage that MWI does have is that it splits the world as a sort of >>>>>>>>> quantum frame dragging that is nonlocal. This nonlocal property might >>>>>>>>> be >>>>>>>>> useful for working with quantum gravity, >>>>>>>>> >>>>>>>>> I worked a proof of a theorem, which may not be complete >>>>>>>>> unfortunately, where the two sets of quantum interpretations that >>>>>>>>> are ψ-epistemic and those that are ψ-ontological are not decidable. >>>>>>>>> There >>>>>>>>> is no decision procedure which can prove QM holds either way. The >>>>>>>>> proof is >>>>>>>>> set with nonlocal hidden variables over the projective rays of the >>>>>>>>> state >>>>>>>>> space. In effect there is an uncertainty in whether the hidden >>>>>>>>> variables >>>>>>>>> localize extant quantities, say with ψ-ontology, or whether this >>>>>>>>> localization is the generation of information in a local context from >>>>>>>>> quantum nonlocality that is not extant, such as with >>>>>>>>> ψ-epistemology. Quantum interprertations are then auxiliary >>>>>>>>> physical axioms or postulates. MWI and within the framework of what >>>>>>>>> Carrol >>>>>>>>> and Sebens has done this is a ψ-ontology, and this defines the >>>>>>>>> Born rule. If I am right the degree of ψ-epistemontic nature is >>>>>>>>> mixed. So the intriguing question we can address is the nature of the >>>>>>>>> Born >>>>>>>>> rule and its tie into the auxiliary postulates of quantum >>>>>>>>> interpretations. >>>>>>>>> Can a similar demonstration be made for the Born rule within QuBism, >>>>>>>>> which >>>>>>>>> is what might be called the dialectic opposite of MWI? >>>>>>>>> >>>>>>>>> To take MWI as something literal, as opposed to maybe a working >>>>>>>>> system to understand QM foundations, is maybe taking things too far. >>>>>>>>> However, it is a part of some open questions concerning the >>>>>>>>> fundamentals of >>>>>>>>> QM. If MWI, and more generally postulates of quantum >>>>>>>>> interpretations, are connected to the Born rule it makes for some >>>>>>>>> interesting things to think about. >>>>>>>>> >>>>>>>>> LC >>>>>>>>> >>>>>>>> >>>>>>>> If you read the link, it's pretty obvious that Carroll believes the >>>>>>>> many worlds of the MWI, literally exist. AG >>>>>>>> >>>>>>> >>>>>>> Carroll also believes that IF the universe is infinite, then there >>>>>>> must exist exact copies of universes and ourselves. This is frequently >>>>>>> claimed by the MWI true believers, but never, AFAICT, proven, or even >>>>>>> plausibly argued. >>>>>>> >>>>>>> >>>>>>> The idea comes from Tegmark, and I agree with you, it necessitate >>>>>>> more than an infinite universe. It requires also some assumption of >>>>>>> homogeneity. >>>>>>> >>>>>> >>>>>> Our universe is, on a large scale, homogeneous. But it can't be >>>>>> infinite since it has only been expanding for finite time, 13.8 BY. I >>>>>> had a >>>>>> discussion with Brent about this some time ago, and he claimed finite in >>>>>> time doesn't preclude infinite in space. I strongly disagree. Perhaps I >>>>>> am >>>>>> missing something. Wouldn't be the first time. AG >>>>>> >>>>> >>>>> I think what you may be missing is that in popular (but misleading) >>>>> accounts of the BB they often say everything originated from a point, >>>>> rather than everywhere at once. To say "everything came from a point" is >>>>> at best only valid for describing the observable universe (or any finite >>>>> portion of the universe) but is invalid to extrapolate it to the whole >>>>> universe, which may be spatially infinite. >>>>> >>>> >>>> I am not assuming our universe began from a mathematical point, but I >>>> do assume that 13.8 BYA it was very very small, the observable and >>>> unobservable parts. >>>> >>> >>> Why do you assume this? Most cosmologists make no such assumption. >>> Under the concordance (standard assumed) model of cosmology, space is >>> infinite. >>> >>> >>>> >>>> >>>> >>>> I don't think there is an implied disconnect between our measurements >>>> of the CMBR and what an observer would measure in parts we have no access >>>> to. It was everywhere hot and dense, and very very small. >>>> >>> >>> There's no observational motivation for the universe being very very >>> small at the beginning. It could have been small, large or infinite, for >>> all we know. >>> >> >> I've never read a description of inflation where the universe is >> described as very large spatially when it initiates. Never. It's always >> claimed it begins a few Planck durations (10^-43 seconds) after the BB, at >> which time the spatial diameter is many orders of magnitudes smaller than >> the diameter of a proton. It then expands to the diameter of the Earth or >> the Solar System before terminating, all this occuring within the first >> second after the BB. AG >> > > I think we need to clearly distinguish between three periods, which are > frequently confused: > > 1. "quantum vacuum phase" Size: ??? Time: ??? > If inflation began as a fluctuation in the vacuum, the vacuum was a > pre-existing initial condition. We can say nothing of it's size or how long > it has existed. Alternatively, this vacuum may have already been in a > state of exponential expansion and required no fluctuation to get started. > > > 2. "Inflation start" Size: (min = Planck size, max = ???) Time: (min = > fraction of second before hot stage of BB, max = finite but otherwise > unlimited time ago). > If inflation started as a fluctuation it could have started very small, > but it would then grow exponentially forever. How big it was when it > stopped for us we can't say, but we can guess it had to have gone on for at > least 10^-32 seconds to fit with observations. This is only the minimum > time, there's no known upper bound. There's not necessarily any cooling > during this time as the heat doesn't enter the picture until inflation > begins to stop somewhere. > > 3. "Local inflation end", Size of inflating space: (undefined but ever > growing), Size of pocket from outside: (finite but growing), Apparent size > of pocket from inside: (finite or infinite depending on shape of the > universe), Time: 13.8 BY ago. > > The "T = 0 of the BB" no longer makes sense in the inflation picture, the > only place we can begin to speak of absolutes with time is when we speak of > the local end to inflation in our pocket. > > Jason >
I'll say it again. One the main reasons to posit inflation is to explain the observable large scale homogeneity of a universe that is now NOT causally connected. If the universe was very very tiny when inflation started, it WAS then causally connected, and inflation preserved the homogeneity. This is what Guth was trying to solve with inflation, among other problems, such as no detectable monopoles. This entire logic breaks down if one assumes an infinite universe at the time of inflation. In this case, the infinite universe was always homogeneous even though it was never causally connected. Further, how could it have been so hot 380,000 years after the BB if it wasn't dense at that time? An infinite universe right after the BB would be COOL, and COOLER after 380,000 years had elapsed. All of the foregoing makes a decent case for a universe which was very very tiny right after the BB. AG -- 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 on the web visit https://groups.google.com/d/msgid/everything-list/14835970-7fed-4715-b63c-b80503356ec9%40googlegroups.com.
