Re: Is the universe computable?

From: John M <jamikes.domain.name.hidden>
Date: Wed, 7 Jan 2004 08:33:58 -0500

Dear George,
to your series of questions I would like to add one as first:
"What do you call universe?"
as long as we do not make this identification, it is futile to
speculate about "its" computability/computed sate.
I see not too much value in assuming infinite memories
and infinite time of computation, that may lead to a game
of words, calling "computation" the object to be computed.
Is 'Multiverse' part of your universe, or vice versa?
Regards
John Mikes

----- Original Message -----
From: "Georges Quenot" <Georges.Quenot.domain.name.hidden>
To: <everything-list.domain.name.hidden>
Sent: Wednesday, January 07, 2004 4:44 AM
Subject: Re: Is the universe computable?


> Georges Quenot wrote:
> >
> > [...]
> > I would be interested in reading the opinions of the participants
> > about that point and about the sense that could be given to the
> > question of what "happens" (in the simulated universe) in any non-
> > synchronous simulation "when" the simulation diverges ?
>
> Thanks for the replies. Until now I feel a bit confuse with them,
> possibly because I do not have an appropriate idea of what is meant
> exactly by "computable" and/or by what accounts for a simulation
> of the universe. I probably have some naive intuition about them.
> So maybe it would help to clarify some points:
>
> By computable, is by default assumed something like physically
> computable using current or future technologies or only formally
> computable (possibly considering virtual computers containing very
> much more memory locations than there are particles in the visible
> universe and for computation times very much longer than the actual
> age of the universe) ? In the latter case, does the memory of the
> computer need to be finite or can it be considered as unlimited ?
> Do the simulation has to end within a finite time or can the
> simulated universe be something like an asymptotic state of its
> description in a given formalism ? Alternatively or in other words,
> could the simulated universe be in some way the limit of a series
> of approximations computed with increasing available memories and
> computation times ? Is "computable" relative to the universe as a
> (spatio-temporal) whole or only to given supbarts of it ?
>
> Also I feel some confusion between the questions "Is the universe
> computable ?" and "Is the universe actually 'being' computed ?".
> What links do the participants see between them ?
>
> Finally, what link is there between the computability of the
> universe and the possibility of its exact description in the
> context of arithmetic ?
>
>
> Maybe too many questions for a single post. I didn't go through
> the whole archive and there might well be already answers to most
> of these so I welcome any reference to appropriate previous posts.
> By the way, are there some FAQs about these questions ?
>
> Georges.
Received on Wed Jan 07 2004 - 10:46:00 PST