Re: Universes with different laws?

From: Marchal <marchal.domain.name.hidden>
Date: Sun Aug 19 09:38:27 2001

Fred Chen wrote:

>The MWI of quantum mechanics (where worlds share common laws and
>characteristics) and the multiverse concept from Tegmark, Schmidhuber, Lewis
>and others ...


An inattentive reading of some of my posts could give the idea
that I (Bruno) belong among the others. To prevent misunderstanding let
me make precise that *in some sense* (explained below) I am closer to
Everett/Deutsch/qm-MWI than Tegmark, Schmidhuber, Lewis.
(Although nuances could be added but I prefer to remain short).


>... (all logically possible universes exist, including those with
>different laws and characteristics)


I believe, like David Deutsch says, that "all
logically possible universe" is a quasi-contradictory notion.
To give a reasonable semantics of *that* "all", you need something
bigger ...

In the comp approach, the "everything" is the running
of all programs,
(which *can* be defined mathematically, and is universal in a sense
deepened by Church Thesis).


The laws of physics are eventually derived
from average possible consistent point of views, and made *necessary*,
The very idea of a "physical universe with other laws" is just
meaningless.

But then any notion of even one universe/multiverse, is given a
phenomenological derivation, without the need to postulate one.


>are very similar, but they are actually
>independent concepts. It is an interesting perspective you bring up where
>all possible universes could actually be MWI-type splittings of a computer
>running a program.


This is common in Schmidhuber and me. But Schmidhuber, to sum up
crudely is like a sort of Bohmian Computationalist, in the sense that
Juergen attachs the "private mind" of the observer to a single
computation,
and this just doesn't work with the comp hypothesis, once we take
account of the first and third person (and other point of view nuances)
differences.

Of course DD postulate a uni/multiverse from a theory (QM) which
is partly empirically infered.
I infer only the arithmetical truth, but I give an
explanation why sound machines believe in universe(s).

I show that comp leads to idealism (UDA). No problem abandoning comp at
that point. But I don't see a contradiction. Quite the contrary
when I translate the UDA in ``the sound machine language", thank
to the work of Godel, Lob, Solovay,(+ Boolos, Goldblatt, Visser, ...)
I got quantum logic for the description of ``probability 1" on the
UD* indeterminacy domain, so the QM confirms a posteriori comp.

Bruno
Received on Sun Aug 19 2001 - 09:38:27 PDT