On Monday, September 16, 2019 at 9:00:46 AM UTC-6, Bruno Marchal wrote: > > > On 14 Sep 2019, at 05:22, Alan Grayson <agrays...@gmail.com <javascript:>> > wrote: > > > > On Friday, September 13, 2019 at 4:08:23 PM UTC-6, John Clark wrote: >> >> On Thu, Sep 12, 2019 at 10:26 PM Alan Grayson <agrays...@gmail.com> >> wrote: >> >> >>> *> 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. What's the argument for such a claim?* >>> >> >> Of course it's been proven! It's simple math, there are only a finite >> number of ways the atoms in your body, or even the entire OBSERVABLE >> universe, can be arranged so obviously if the entire universe is infinite >> then there is going to have to be copies, an infinite number of them in >> fact. Max Tegmark has even calculated how far you'd have to go to see >> such a thing. >> > > What I think you're missing (and Tegmark) is the possibility of > UNcountable universes. In such case, one could imagine new universes coming > into existence forever and ever, without any repeats. Think of the number > of points between 0 and 1 on the real line, each point associated with a > different universe. AG > > > > Tegmark missed this? > > Deutsch did not, and in his book “fabric of reality”, he gave rather good > argument in favour of Everett-type of multiverse having non countable > universe. That makes sense with mechanism which give raise to a continuum > (2^aleph_0) of histories, but the “equivalence class” brought by the > measure can have lower cardinality, or bigger. Open problem, to say the > least. >
*What you're not addressing is that with uncountable universes -- which I haven't categorically denied could arise -- it's not obvious that any repeats necessarily occur. I don't believe any repeats occur. AG * *As to your general theory, that with mechanism (replacing brains and presumably consciousness, with digital copies), computability, and the natural numbers, we can derive the physical universe we observe. This is your theory, isn't it? If so, I just don't see it as explanatory. AG* > Your closest identical copy is 10^12 light years away. About 10^76 light >> years away there is a sphere of radius 100 light-years identical to the one >> centered here, so everything we see here during the next century will be >> identical to those of our counterparts over there. And 10^102 light years >> away the is a exact copy of our entire observable universe. And all this is >> true regardless of if the Many Worlds Interpretation of Quantum Mechanics >> is correct or not, it only depends on the universe being spatially infinite. >> > > But our universe is NOT spatially infinite if its been expanding for > finite time, starting very small, as can be inferred from the temperature > of the CMBR. AG > >> >> >> Is there a copy of you >> <https://space.mit.edu/home/tegmark/PDF/multiverse_sciam.pdf> >> >> * > Morevover, I don't believe a universe of finite age, such as ours >>> which everyone more or less agrees began some 13.8 BYA, can be spatially >>> infinite.* >>> >> >> I see no reason in principle why something can't be finite along one >> dimension and infinite along another dimension. >> > > In general, one can of course have some dimensions finite and others > infinite. But if *our* universe is *finite* *in time* since the BB, 13.8 > BY, its spatial extent must be finite, since that's how long its been > expanding. AG > > > I agree with Grayson here. (Accepting a lot of premises, like the BB is > the beginning of the physical reality, which I doubt). > > Bruno > > > > >> John K Clark >> >> > -- > 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 everyth...@googlegroups.com <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/5a270b8e-3bf2-4d34-b0e7-4e0daa3cebce%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/5a270b8e-3bf2-4d34-b0e7-4e0daa3cebce%40googlegroups.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 on the web visit https://groups.google.com/d/msgid/everything-list/e558a41c-3784-4298-80be-52a5e6f45f7f%40googlegroups.com.
