On Mon, Oct 17, 2011 at 07:03:38PM +0200, Bruno Marchal wrote:
> >This, ISTM, is a completely different, and more wonderful beast, than
> >the UD described in your Brussells thesis, or Schmidhuber's '97
> >paper. This latter beast must truly give rise to a continuum of
> >histories, due to the random oracles you were talking about.
> 
> 
> All UDs do that. It is always the same beast.
> 

On reflection, yes you're correct. The new algorithm you proposed is
more efficient than the previous one described in your thesis, as
machines are only executed once for each prefix, rather over and over
again for each input having the same prefix. But in an environment of
unbounded resources, such as we're considering here, that has no import.

So the histories, we're agreed, are uncountable in number, but OMs
(bundles of histories compatible with the "here and now") are surely
still countable.

If we take the no information ensemble, and transform it by applying a
universal turing machine and collect just the countable output string
where the machine halts, then apply another observer function that
also happens to be a UTM, the final result will still be a
Solomonoff-Levin distribution over the OMs. This result follows from
the compiler theorem - composition of a UTM with another one is still
a UTM.

So even if there is a rich structure to the OMs caused by them being
generated in a UD, that structure will be lost in the process of
observation. The net effect is that UD* is just as much a "veil" on
the ultimate ontology as is the no information ensemble.

Unless I'm missing something here.

> 
> 
> >
> >Lets leave the discussion of the universal prior to another post. In a
> >nutshell, though, no matter what prior distribution you put on the "no
> >information" ensemble, an observer of that ensemble will always see
> >the Solomonoff-Levin distribution, or universal prior.
> 
> I don't think it makes sense to use a universal prior. That would
> make sense if we suppose there are computable universes, and if we
> try to measure the probability we are in such structure. This is
> typical of Schmidhuber's approach, which is still quite similar to
> physicalism, where we conceive observers as belonging to computable
> universes. Put in another way, this is typical of using some sort of
> identity thesis between a mind and a program. 

I understand your point, but the concept of universal prior is of far
more general applicability than Schmidhuber's model. There need not be
any identity thesis invoked, as for example in applications such as
observers of Rorshach diagrams.

And as for identity thesis, you do have a type of identity thesis in
the statement that "brains make interaction with other observers
relatively more likely" (or something like that).

There has to be some form of identity thesis between brain and mind
that prevents the Occam catastrophe, and also prevent the full retreat
into solipsism. I think it very much an open problem what that is.

> Unfortunately the mainstream scientists still ignore the first
> person indeterminacy today, meaning that they just ignore the
> 1-person / 3-person distinction---not mentioning the mind body
> problem (and, to be sure,  I still don't know if this comes from a
> genuine non understanding, or if it is still the problem of
> acknowledging my work, which would be a notoriety problem for some).
> 
> As I said, I don't know if the problem is really genuine, for the 1-
> indeterminacy, which is rather a simple notion. Some researchers
> told me that it is a problem to cite my name, but not so much my
> work if they change the vocabulary.
> 

Wow, you must've really got some people's noses out of joint.

Incidently, New Scientist has a recent article about dastardly deeds
done in science, including some well know ones like Newton's treatment
of Hooke and Watson & Crick's treatment of Franklin. Even Einstein
gets a serve about claiming the equation E=mc^2 for himself.

> What a pity, what a waste of time. It is less tragic than the
> illegality of cannabis and drugs, but it is seems clear that human
> corporatism leads to an accumulation of human catastrophes,
> everywhere. Corporatism perverts democracies and academies. This has
> an unavoidable costs and moneys based on lies has no genuine value.
> 
> The rule "publish or perish" is also both a killing-science and
> killing-human procedure: it creates a redundancy which hides the
> interesting results, and it multiplies the fake researches.
> Ranking the number of citation creates circular loops of people
> citing each others and not much more.

It also creates the psychopathic reviewer, who does all to undermine
the credibility of a paper. I have experienced one or two like that -
not many, but its still a nuisance.

>  It is a nonsense. A researcher who does not find or solve something
> should NOT publish, but should not perish either. He should still
> allow to search. 

Well its more about lack of funding. One can research anything one
desires if you are independently wealthy, or have an independent
income stream (like myself). Of course, getting attention of other
scientists is a different matter! Nevertheless, current funding styles is
damaging to the integrity of science - gone are the days when
researchers would write papers and put them in their filing cabinet
for 3-6 months before submitting to a journal. I think David Deutsch
may have done something like that, but I recall Schroedinger famously did
something like that as a matter of course.

> A researcher can be asked to write reports and to
> justify the difficulty of his task, but in science, and especially
> in fundamental science, findings cannot be ordered(*).  OK, I
> digress :)
> 
> Ask any question if I am unclear,
> 
> Best,
> 
> Bruno
> 
> (*) Note that there is a 'slow science'  awakening:
> http://slow-science.org/
> 

Hmm - I'm not sure I agree completely with the slow science
manifesto. Email exchanges like this are really good for fomenting
science. I never thought attempts at online conferences worked that
well - eg MUDs and the like, as there was not enough time to think
about other people's comments. Twitter might be alright for sharing
reading lists - one could tweet about an excellent paper, perhaps,
although personally I haven't gotten into it.

Academies are all very well, but don't work well with people with
family commitments, or who need other sources of income (or simply
have other businesses) to live. My PhD was done in such an academy, an
Australian "Institute of Advanced Studies", modelled on the Princeton
one. I would have to say that the place was rather moribund,
unfortunately - a few bright stars, but a lot of dead wood.

Cheers

-- 

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Prof Russell Standish                  Phone 0425 253119 (mobile)
Principal, High Performance Coders
Visiting Professor of Mathematics      hpco...@hpcoders.com.au
University of New South Wales          http://www.hpcoders.com.au
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