Re: The Old Worlds repeating themselves?

From: Marchal <>
Date: Wed Sep 26 04:06:01 2001

Gordon wrote (in the FOR list):

>There is MORE, wether we humans find it is another thing but
>the Physical Program isnt over yet!

> [...]
>The wider approach:
>Thought (Guess Reason Creativity.......)
>Experiment-Physical(in what ever way Nature throws it at you)

You talk like if I was *proposing* COMP as the TOE which
should replace Physics. Obviously you believe in a
*apparently* wider vision.

I try to comment shortly this in two ways:

1) A weak way:
I don't think it is possible to explain the physical laws
by taking for granted a physical law. Of course observations
and inferences of physical laws can help, but those who
search for an explanation of the existence of the physical
laws (and not just for a compression of the empirical
information) must jump outside physics at some stage.
Now, it is possible to justify that a TOE without the
natural numbers cannot justify natural numbers. So a minimal
TOE must be an extension of some arithmetics.
Then, incompleteness phenomena can explain why it is quite
possible we don't need to postulate anything above numbers.
So why should we postulate a "physical reality" nobody has ever
been able to define?

2) A strong way:
The computationalist hypothesis (comp) in the cognitive science
entails the incomptatibility of the weak materialist assumption
(the assumption that there exist independent substances).
Comp makes possible to reformulate the mind-body problem, and
it takes necessarily the form of justifying sort of average
conditional belief in apparent substance by universal machine,
where belief is defined
axiomatically: B(p) must verify B(p->q) -> (Bp -> Bq), etc.
I like to express this result as: comp -> reversal between
physics and (machine) psychology.
'course, I may be wrong, but then I would like to know where.
(look at the UDA).

Please, be aware I am not saying that COMP is a panacea capable
of explaining everything. The UDA shows exactly the contrary:
if we take the comp postulate seriously we have to justify
machine beliefs in matter/energy/time without postulating
matter/energy/time. That's all.
At this stage physics is redined as the search of a relative
measure (integral) on the consistent extensions computationaly

UDA is only one half of my thesis.
The miracle is that, following Godel, you can translate the UDA
in pure arithmetic, and you can (thanks to important works
mainly by Grzegorczyk, Segerberg, Solovay, Boolos, Goldblatt,
Visser) extract the logical structure of that space of
computationally accessible consistent extensions. We get a sort
of quantum logic. (This is the second half of my thesis)
To day it looks like that logic is rich enough for defining
universal quantum computing (thanks to Deutsch fundamental
discovery of universal quantum computing, but also some more
recent paper like the Rawling and
Selesnick in the journal of ACM 2000)

Only the future will confirm that it is or that it isn't a
mirage. That could very well lead to a refutation of comp.

>Much of 'Science and Sanity ' has been incorporated into our
>culture without any direct reference to it. Most people remember
>Korzybski's phrase 'The map is not the territory; the map doesn't cover
>all of the territory; and the map is self-reflexive (it becomes part of
>the territory)'.

Yes. In particular if you embed the map in the territory, there
is a point of the map which will refer correctly to its own
position. Something similar happens with comp. There exists
set of key invariants, fixed points, for computational transformations
in computational spaces.

David Deutsch insists we take our theories seriously, and I am
just saying that those who postulate comp should take seriously the
very counterintuitive and big consequences of that postulate.

There is no reason to think that comp will stop the Physical
Program. I even expect the contrary. I'm open to the idea that in the
future, comp will perhaps predict that any unifying theory of the empiry
can be empirically refuted, perhaps even constructively so.
(But I have always fail in trying to prove that, to be honest).

Received on Wed Sep 26 2001 - 04:06:01 PDT

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