Re: All feedback appreciated - An introduction to Algebraic Physics

From: Bruno Marchal <>
Date: Thu, 8 May 2008 16:12:33 +0200

Hello GŁnther,

> thanks for the long and informative post.

Y're welcome.

>> Hmmm.... The UDA should just show that, and I am not sure which points
>> you are missing. Suppose there is a physical concrete universe and
>> that
> I know that I am missing a point somewhere :-)
> I have printed out your post and will work it through carefully, it
> will
> take some time before I can respond.

My fist-person-everything-list is not aware of the delays .... (joke).
Take all the time needed; I'm myself a bit busy.

>> Please ask any questions.
> Thanks, as said above, will take some time.
>> Be sure you have completely grasp the first
>> person comp indeterminacy before anything else (but the 1-3
>> distinction
> 1-person indeterminacy is no problem.

OK. Note that Wallace says that it is controversial, but he does not
give reference, except perhaps some work by Hilary Greaves, which seems
to me a bit a play with words (with respect of what I'm trying to
convey, it could be a 1004 fallacy). Even if she is relevant in some
context, it is not at our stages. I will perhaps come back on this
later. The key point is that she accepts eventually Wallace's
explanation of Deutsch "decision-theoretic" account of the Born rule.
 From this, with or without the "indeterminacy or uncertainty" wording
means that, once she get the UDA reasoning, she will have (as rational
agent) to accept that with the comp hyp, the whole SWE has to be
retrieved if only for decision theoretic reason.
As a matter of tatste I don't like to much the decision theoretic
wording because it can be misused by instrumentalist philosophers, but
after all that is their problem, not us's. (if that is english ... I
guess not, Hope you see what I mean).

> My problem begins along steps 6-8,
> especially when you dump the physical universe :-)
> This also relates to the duplication issue in the Bostrom paper:
> when one presupposes physicalism, then duplication seems to be the
> "proper" attitude - especially combined with a monist identity theory
> of consciousness with matter (no supervenience or stuff, see this paper
> for what I mean:
> Galen Strawson, 'Realistic monism: why physicalism entails
> panpsychism' 2006

Strawson has a very personal definition of physicalism, but at least he
is well aware of the "mind-body" problem.
Then he is not aware of UDA, and still believe in concrete objects,
which forces him to panpsychism, which I find rather unclear and
unnecessary. I don't think his position is coherent with the comp hyp,
unless you put 'arithmetical truth" in the mind (but this is, from the
comp point of view (after UDA and AUDA) a bit to much pretentious to
say the least. Almost blasphemous.

> It is really good (for physicalists at least :-))

Hmmmm ... for "physicalist" in Strawson's broad and unconventional
sense of physicalism.

> And, as mentioned, I don't quite see how adoption of comp throws out
> physicalism (I understand the argument, but what about parallelism - is
> it a measure theoretic argument then against physicalism?).

Yes. With "naÔve" comp, there are too many white rabbits and white
noise. But the incompleteness phenomenon prevents to use this as a
refutation of comp. There is still some room for destructive
interference (of the white rabbits) and granular linearity.
And if comp is correct (and my argument valid) then the whole of
physics is derivable from computer science (intensional number theory).
Only geography and history will remain contingent.

> (Addendum: I mean physicalism in the broadest sense: I do not need
> Aristotelian substance or whatever, simple structural relations ŗ la
> platonic computations suffice -> this is no standard position, but I am
> working on this;


> the main difference between your position would be that
> the SR variant

I guess SR variant = structural relation variant.

> includes spatiotemporal coordinates (at least from the
> frog view) which could lead to duplication for identical computations
> except for spatiotemporal labels)

Hmmm.... geometry has to be derived from arithmetic too, and most
probably from the 1-person points of view.

> Assuming your variant (comp, yes doctor, AR):
> I would be interested in what happens if, in a computational history,
> you start seeing another "you" being simulated: like a russian doll,
> comp within comp-> let us say you construct a VR that simulates for the
> VR Bruno the same environment as the "outside"/"mainline comp" Bruno
> sees -> would this comp within comp then add to the "outside" Bruno
> measure?

Only relatively to the state of mind of the "bruno outside", and this
before you make the simulation run. And somehow the simulation has to
depart, bifurcate or differentiate from the "original", if not
unification takes place instead of duplication (in Bostrom's sense).
Two infinite exactly identical computations does not add up from the
measure theoretic point of view. Only relatively differentiating
computations do.

> (I hope it is clear what I mean) - anyway, I have written more
> than I wanted, another (real) response will follow when I have found
> the
> time to think through your previous answer to me.

Take it easy.

> Thanks again for your effort to make clear yours ideas, it is well
> appreciated!

Thanks, have a good day.


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Received on Thu May 08 2008 - 10:15:53 PDT

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