Re: Everything is Just a Memory

From: Marchal <>
Date: Mon Jan 31 06:50:33 2000

>I (and others) have always tried to keep AUH's, and MWI's of QM (including
>Everett), as two distinct concepts. For my own favourite AUH (which is quite
>close to Tegmark's hypothesis), there are three possibilities, where in each
>case one or more MWI's are encompassed within the AUH, provided they form
>consistent theories in their own right.
>(a) If all MWI's are inconsistent, they are not represented in the AUH -
>this would appear unlikely.
>(b) The simplest consistent MWI (cet. par.) does not provide the highest
>measure for SAS's of our kind - again this would appear unlikely, because we
>would count ourselves unlucky if the theory that gives the highest measure
>for our kind (and therefore the theory almost certainly describing our
>universe) happens to look indistinguishable from QM-based many worlds
>(c) The simplest MWI *does* give the highest measure for our type of SAS -
>this seems the most likely scenario out of (a), (b) and (c), but is not
>*necessarily* the case.

I agree that a priori AUH is more general than MWI (Everett's one to
"fix" the things). Do you agree that if AUH > MWI then QM should be
empirically false,
unless you can explain from your AUH why empirically we "see" only MWI.
IF AUH = MWI, the white rabbit problem is "solved" by the decoherence
phenomenon, OK?. And with pure comp, if AUH = MWI, the white rabbit
problem is "reduced" to the
derivation of MWI (QM) from psychology/computer-science/number-theory.

Of course here we are vague. With comp we are warned: the day we give
a name to our favorite plenitude: BAM! Wellcome the many-plenitudes

My problem with your (and others) type of everything approach is that you
seem to take the "worlds" for an intuitively clear notion. But even with
Everett MWI, I am not sure that this is clear enough.

Do you know :
Today my favorite "interpretation of Everett's interpretation of QM" is
Mermin's Ithaca interpretation. See the paper by Mermin at ..., see also
Adami and Cerf approach to the quantum information theory. And see the
adress for a clear and short
description of Ithaca's interpretation.
My work can be seen as an Ithaca interpretation of arithmetic where UTM
play the role of observer.

>I have been, and still am, interested in the conceptual foundations of your
>thesis, Bruno, but have been waiting for an english translation. Should I
>continue to wait, or have you the patience to answer some *very* basic
>questions (like how you cope with the WR problem, and how is the appearance
>of physics generated)?

In a nutshell the UDA shows that
 how I cope with the WR problem = how is the appearance of physics
In my thesis (and in all my papers) there is two parts:
1) a proof that comp implies that physics is ontologically and
reducible to the psychology of machines (which is itself a branch of
computer science). That is the Universal Dovetailer Argument (UDA).
2) an attempt toward an explicit derivation of the logic of the physical
propositions based on a formalisation of the UDA in pure arithmetic.
(This is more technical: modal, quantum logic, provability logics...)
Strangely enough I got rather easily a sort of quantum logic.
Now my problem is to derive a probability calculus from that logic. This
difficult: I'm still lacking a semantic for my "quantum logic".
Conceptually the problem is to explain the quantum probability rule: to
explain why we must add amplitudes and not probabilities in the case
we ignore in which computational history we belong ...

For the point 1), look at the UDA post I send today. For the point
2) wait for the translation of my thesis or wait for some post, thanks.
(While waiting you can read Boolos's book on the provability logics).


Received on Mon Jan 31 2000 - 06:50:33 PST

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