[FRIAM] cosmic underdetermination theorem

[Sarbajit Roy]

This may be the first paywalled PDF (attached)

On Wed, Jan 29, 2025 at 11:51 PM Santafe <desmith at santafe.edu> wrote:

> btw, thank you for this.
>
> Like the cosmic horizon, both the top link and the journal article are
> behind paywalls.  But the university could get me the second one.  A 3-page
> paper.  Amazing.  I read the construction, and think I follow the claims.
> I haven’t spent time looking at the manifolds he constructs, enough to
> convince myself that I can see them.  But that’s just time.
>
> Eric
>
>
>
> > On Jan 29, 2025, at 10:06, glen <gepropella at gmail.com> wrote:
> >
> >
> >
> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fiai.tv%2farticles%2fthe-universe-is-unknowable-from-within-it-auid-3057&c=E,1,AwRg2KvGth_GUJNej88XfasttX1aPURydaXEN5gmJ6dMKxuwMl3JdpIAkGubWAXi5tfnWlj8tgE1UycYvSgY6FNlCIwxJuhaShCol9rByga_qoOi2vlrfEmGWvAh&typo=1
> >
> > "In light of the situation, one might insist that spacetime have certain
> global properties instead. But what justifies this move? Given the theorem,
> we know this justification cannot be due to any observational data we have
> collected -- even after allowing for any local induction on such data.
> Perhaps one could appeal to some strong form of global induction. For
> example, the Copernican principle could be invoked which seems to modestly
> deny us a special status in the cosmos: the observable universe is presumed
> to be representative of the entirety of spacetime. But as the philosopher
> John Earman has aptly remarked, "this seeming modesty is belied by the
> immodest use to which the principle is put in justifying an inductive
> extrapolation'' [9]. Indeed, induction on such vast scales would seem to be
> suspect given that we are able to observe only the tiniest fraction of the
> universe [10]. Remember the ants!"
> >
> > 2 of the interesting references are here:
> >
> > Manchak, J. (2009), "Can We Know the Global Structure of Spacetime?"
> Studies in History and Philosophy of Modern Physics, 40: 53-56.
> >
> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fdoi.org%2f10.1016%2fj.shpsb.2008.07.004&c=E,1,37U3FCfmt2kwwoKkBsYaXr_rchHZnkSAi9xBTqlvvdv028Es-FGPFjYp8EdtMUAU1hhZ5Z1U0wHTkLD1l91G3KQBPW3CsXm9qS9sgXrDdMH_1K1PQzHg_4-6NQ,,&typo=1
> >
> > Malament, D. (1977), “Observationally Indistinguishable Space-Times,” in
> J. Earman, C. Glymour, and J. Stachel (eds.), Foundations of Space-Time
> Theories, Minnesota Studies in the Philosophy of Science, Volume VIII,
> Minneapolis: University of Minnesota Press, 61-80.
> >
> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fdoi.org%2f10.1086%2f288937&c=E,1,Q_uB9n6h8cuxI8PJfJUAUXEneL5kf0t-_7I3B0hD5dKR_BsE-8DV8QnxeWQrawsI-DjEs7bq0UpHjFOtH-Hfxukjcd2VW0D-u4jftuuEbvf7eIngs1-0vXmmLyU,&typo=1
> >
> > --
> > ¡sıɹƎ ןıɐH ⊥ ɐןןǝdoɹ ǝ uǝןƃ
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> >
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