>
> Russell Standish wrote:
>
> >> No fine tuning means that any value of \alpha is allowed (at least
> >> physically consistent values). So the above range you quote is
> >> extremely fine-tuned. In reality, the level of fine-tuning is likely
> >> to considerably less (I'm not sure what Tegmark quoted, but I thought
> >> the allowable range was a few percent of \alpha - which is still
> fine-tuned).
> >
>
> Fred Chen answered:
>
> >Since I believe this to be subjective, I respect your definition of
> >"fine-tuning,"
> >even your choice of adverb "extremely." But this also leads to an
> >interesting
> >conclusion: any SAS will perceive fine-tuning (as per your definition). So
> >we can call
> >this generalization of SAP/WAP the SAS-centric principle, or something
> >like that.
>
> I agree. But then you should try to make SAS precise. As most people know,
> I have proposed here the choice of self-referentially correct universal
> turing machines.
>
> Bruno
>
>
Since there is the possibility of a non-tuned physics, surely the
distinction between SAP and WAP is still there. However, as soon as a
AU or MW hypothesis is accepted, then the distinction between WAP and
SAP is meaningless, as I've long argued.
As I have mentioned earlier, I disagree that SASes are Turing
Machines, however I'm reasonably comfortable that they should be
capable of universal computation. I'm slightly less comfortable in
assuming that they are consistent, but let's press on assuming that
this is a property of SASes.
I guess what I'm trying to say, is that I think Bruno has his
arguments backwards. He starts off assuming a strict form of
computationalism, then demonstrates via the filmed graph argument that
this induces a form of computational indeterminism, requiring a many
worlds picture to resolve it.
>From my perspective, the AUH is the base axiom, and from a AUH or MW
perspective one can see how counterfactuals and free will enter into a
deterministic universe, and why the filmed graph argument doesn't
apply. In particular, the free will issue shows how SASes differ from
Turing Machines.
BTW - I do believe in a slightly more relaxed version of
computationalism. For example if your were to replace one of my
neurons by a machine that modelled that neuron sufficiently
accurately, I'm sure I would survive. Repeat the process, until no
more neurons were left, and I have undergone a replacement of my brain
(and survived), modulo the issue of ensuring that the chemico-hormonal
system is also modelled sufficiently well.
With a bit more effort (and monstrous internet charges), one could
arrange for this replacement to happen at a distance, in effect
performing the teletransportation experiments Bruno describes in his thesis.
I don't believe neurons are Turing emulable - in particular, neurons
are not perfectly deterministic.
Some of Bruno's results hold for this more relaxed version of
computationalism. Unfortunately, I don't yet understand his arguments well
enough to know which ones.
Cheers
----------------------------------------------------------------------------
Dr. Russell Standish Director
High Performance Computing Support Unit,
University of NSW Phone 9385 6967
Sydney 2052 Fax 9385 6965
Australia R.Standish.domain.name.hidden
Room 2075, Red Centre
http://parallel.hpc.unsw.edu.au/rks
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Received on Thu Dec 09 1999 - 15:40:39 PST