Re: Is the universe computable?

From: Georges Quenot <Georges.Quenot.domain.name.hidden>
Date: Wed, 07 Jan 2004 21:33:03 +0100

John M wrote:
>
> Dear Georges,
> to your series of questions I would like to add one as first:
> "What do you call universe?"

I would naively answer: the universe in which I live
according to the current intuition I have of it. I am
not sure this makes sense and I also understand that
others may have different intuitions of it. Maybe a bit
more formally I would refer to "the smallest independent
piece that does include myself" (in case there is anything
else and hoping that we can get a common intuition of that;
dependence is relative to space-time continuity, particle
interaction and this kind of things).

> as long as we do not make this identification, it is futile to
> speculate about "its" computability/computed sate.

Maybe this is an opportunity to clarify the concept and
to see up to which point it is shared among us. I am not
sure we can easily go much farther than intuition we have
of it and to isolate the possible differences we have.

> 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.

Maybe I was just not clear enough. I was just thinking of
the possibility to simulate the universe at any level of
accuracy. However small but non zero the accuracy, there
would exist a simulation of finite but possibly very large
size and time that meets it. Infinite memory and running
time would be necessary only to run an infinite sequence of
simulations with an accuracy going asymtotically close to
zero.

> Is 'Multiverse' part of your universe, or vice versa?

I am not sure I understand the concept(s) of multiverse
enough to make a reasonable answer to this question.
For what I understand of it (them), it is (they are) not
consistent with the view I have of causality (which is
more related to the fact that the universe is "more
ordered on one side that on the other" than to dominos
pushing each other).

Regards.

Georges Quénot.
Received on Wed Jan 07 2004 - 15:35:49 PST