In answer to Wei dai's question, what is the set of all possible universes,
I would say, it is the set of all universes which can be rendered by mapping
a subset of the output of "LET A=A+1; GOTO START", however you wish to map
it. I'm not sure why we want to know if we are living in 'this particular
turing machine' - as far as I understand it only one machine is running. It
generates everything possible as per previous paragraph, so what the program
looks like can only be known if we know the mapping and all that seems like
a fruitless avenue of research.
I'm confused: why do we need to explain anything? If everything possible
exists then that X exists in our environment can never be very surprising.
I've ordered the book, and I'll try and make time ot read it.
> -----Original Message-----
> From: Marchal [SMTP:marchal.domain.name.hidden]
> Sent: Thursday, March 18, 1999 9:13 AM
> To: Higgo James; 'everything-list.domain.name.hidden'
> Subject: RE: delayed reply
>
> James wrote (recently):
>
> >It seems we're in agreement. You are better placed to spread the gospel
> of
> >the short program - didn't someone say the 'universe is counting' or
> >something? And you're the best person to complete the all-important
> >exercise:
> >
> >Exercice : From the statement
> >
> > "LET A=A+1 GOTO START" generates the universe.
> >
> >Prove (and make precise) that
> >
> > Universes are related to
> > other universes only by correlation,
> > which is a subjective feature.
> >
> >Regards
> >James, Eagle and Serpent.
>
>
> Yes the "exercice" is all important with respect to this discussion list.
> Remember Wei Dai's old question:
> (http://www.escribe.com/science/theory/msg00002.html).
> You can also try to guess what is missing in a typical "Schmidhuberian"
> reply. (for exemple: http://www.escribe.com/science/theory/msg00082.html).
>
> Let me try to put things another way:
>
> OBSERVATION gives Standart QM, which is [Schrodinger Eq + Collapse].
>
> EVERETT Theory is given by an ontology obeying [Schrodinger Eq];
>
> THEN Everett & Co. gives an phenomenological explanation why we (as
> machines) will observe the Collapse (with the right probability).
>
> WEI DAI-SCHMIDHUBER-HIGGO-... Theory is an ontology given by [the
> counting algorithm], including the minimal amount of number theory or
> computer science to provide meaning to the counting algorithm (of course).
>
> That is a very nice Pythagorean Theory, but, what I say, is that, if we
> pretend that it is an explanation for "everything", then we MUST provide
> a
> phenomenological explanation of BOTH Schrodinger eq. AND the collapse.
>
> 5O% of my thesis (http://iridia.ulb.ac.be/marchal) makes that obligation
> precise. I mean 50% of my thesis explain why, if we believe in comp, we
> really must and can derive a non trivial part of QM from classical
> computation theory. The other 50% gives a precise attempt toward such a
> derivation. The "easy" part is the quantum qualitative aspects
> (indeterminism, non-locality, many-worlds phenomenology, quantum logic,
> etc.). The difficult part is the (classical) hamiltonian smoothness.
> BTW I discover recently some interesting clues toward that goal in the
> impressionning paper by Tommaso Toffoli "Action, or the Fungibility of
> Computation" in the nice book edited by Anthony J. G. Hey "Feynman and
> Computation", Perseus Books, Reading, Massachusetts, pp. 349-392.
> I recommand the whole book for those interested in the "information or
> computation" thread.
>
> A+ Bruno.
Received on Thu Mar 18 1999 - 01:36:52 PST