Hi Bruno,

Thanks for your answers. I follow you in passing on our points of agreement (and erasing them).

Godfrey Kurtz
(New Brunswick, NJ)

-----Original Message-----
From: Bruno Marchal <[EMAIL PROTECTED]>
Hi Godfrey,

I see we agree on many things. I comment only where we take distance.

Le 12-août-05, à 19:33, [EMAIL PROTECTED] a écrit :

> [GK]
> That is a wonderful point you make above! But my own was that > acknowledging something may not exactly be the same as admitting its > reality; it can in fact be just the opposite when what is acknowledge > is someone else's belief for instance. How > (consensual) reality is acquired is a pretty complicated and still > mysterious process. I would venture that a lot of what we
> would count as "subjective reality" is just that! (more below)

I am not sure I understand you, and pêrhaps it is just a question of vocabulary. If I acknowledge a belief of someone, it seems to me that I take as real (or very plausible) that that someone has a belief, not that the belief is true. Altough the subjective reality is just that, I guess, subjective. I take as objective the existence of "subjective reality", or at least I take as objective the existence of the discourse and silence on subjective reality, and what I am searching an explanation on is exactly that, how to explain in objective term the subjective discourse, including the fact that we know we cannot make objective that subjectivity. This is part of the so-called mind-body problem. Saying, like Lee, that my subjective view is neurons firing is just false. To say that it is the sult of neurons firing is much more interesting but actually makes the problem worse (as serious philosopher of mind know very well). The reason is that if neurons firing explains all my behavior, it is just more enigmatic that something like consciousness has ever evolved. The explanation is more subtle and demanding and eventually forces us to revised our oldest prejudices about the nature of reality.

The point I am trying to make is that a lot of your back and forth discourse on the 1st versus the 3rd person misses the 2nd person in between them! More specifically: I am quite convinced that one good part of what we call "the Mind" or "the Self" and perhaps even "Consciousness" is generated by social interaction rather than by any "inner realm of subjectivity". I suspect this is true about all of what we call "symbolic" or "meaningful" including a lot of the support for mathematical understanding though I guess I am a platonist to the extent that I think of mathematical objects as existing independently
of any of our semantics in a realm of their own.

As for consciousness I do agree with you that whatever explains it may seriously require a revision of our oldest and, very possibly, some of our newest prejudices about reality but certainly most of outr old prejudices about... consciousness-
yours (and mine) included! ;-)

... skipped

> If I understand it correctly this is that one materially supported > conscious entity could > be entirely (and analytically) replaced by a digitally constructed > one without it even being conscious of it. Am I right? Is > this what you COMP ? If so you are right in one thing: it is one hell > of a stronger contention than the strongest AI hyp
> (and that much more unlikely).

OK. But please note that 99,9% of the scientists take it for granted. Actually I know only Penrose postulating explicitly the negation of comp. This forces him to speculate about the falsity of both quantum mechanics and general relativity.

I would rather not bring Penrose to this discussion though he is someone I much appreciate and will not easily dismiss. Unfortunately I can't claim I understand his Byzantine time-asymmetric proposals as alternatives for QM and GR enough
to criticize them, and I am not alone in this.

But I thought about your COMP and such over the weekend and I realized I have to take back what I said above! I can perfectly well imagine a world in which no one has yet built a conscious machine from scratch but someone has found a procedure for replacing one's consciousness by a digital one in the way you describe. Why should one imply the other?

I didn't say that either. I don't know if I am a genious, but I don't know if I am not a genious either ;-)

Oh, Bruno, don't be so bashful ...

> And since you are a machine your years and years
> and years may surely add to two centuries! No wonder you outrun your

I have never said that I am a machine. I have not the slightest idea if comp is true. But I am sure that if comp is true then physics emerges from the arithmetical relations, well, as sure as I am sure of the irrationality of the square root of 2. I give a proof.

Oh, I am sorry, than! As you speak so much of acts-of-faith I concluded, too soon I gather, that you took all those years of toil
as a consequence of your beliefs. Silly me!

> [GK]
> Oh but you make it sound so easy! See: its is the "derive physics > from computer science" that I have my first problem with!

That is the object of the proof I gave. The proof is 100% third person accessible, like any proof. What is hard, perhaps, is that the proof is done in a field which is in the intersection of theoretical physics, theoretical computer science and theoretical cognitive science.

And just how sure are you that there is such an intersection? Or is that also an article of faith?

> Easier said than done, I'm afraid. Stephen Wolfram sent me his huge
book but I remain as unconvinced by it as everyone
> else who has read it about his "tinker bell" version of Quantum > Mechanics. I heard Ed Fredkin a number of times and, > though he is quite charming, I don't think he has any better answer
to that question...

Wolfram, like Schmidhuber, entirely dismiss the 1/3 distinction. The proof I gave shows that Wolfram is just wrong on those matter. I am nearer Svozil and Chaitin (but well beyond, probably).

If I thought Svozil and Chaitin were near at all I might understand you better. At least we agree that Wolfram is wrong!

> More specifically: I believe QM puts a big kabosh into any > non-quantum mechanistic view of the physical world. If you > don't get that, than maybe you don't get a lot of other things, > Bruno. Sorry if this sounds contemptuous. It is meant
> to be.

It does not seem contemptuous, it seems just circular. If you have the two following axioms:

1) There is a physical world
2) The physical world is described by QM

Then it seems obvious to me that "QM puts a big kabosh into any non-quantum mechanistic view of the physical world".

Now don't worry, I believe more in the quantum than in comp! I thought, in the past, that I would quickly refute comp with quantum mechanics. But the fact are there, comp, as far as it has been tested implies everything we can deduce from the quantum. Comp is not yet refuted, and evidences add up that the quantum is derivable from comp (or from numbers through comp).

Of course, I believe in the quantum, but if comp is correct, I can no more believe in "1)", i.e. I must abandon the existence of a physical world, and the quantum describes only the way machine dreams interference generate the stable illusion of solidity and time from arithmetical truth (under the form of confirmable bets, the Lobian Bp & Dp).

Lots of "ifs" in there! Since you found me circular let me just ask you this:

If the physical world does not exist (you say that COMP implies this) why even bother deriving physics? Can't machines dream just like we do, about lovely, terrifying and yet unphysical things?

Also, I suspect that I can with just a bit of work, show you that QM invalidates your COMP hyp if I actually understand it. Would you be so kind as to state it out for me in one full sentence so I have a clear" line-of-sight"?

> Incidentally, the reverse reduction of computer science to physics > seems to be a lot more hopeful specially since most > computations seem to run a lot faster in physical computers than > on... (what are the alternatives again?).

If you study the Universal Dovetailer Argument, you will see that any machine betting correctly and consistently on any piece of "observable" reality, will bet that to simulate that piece of reality exactly, there is a need of simulating an infinity of computations. Remember we don't know in which computations "we are", and the "physical" appearances emerge from some probabilistic interference among all the possible computations. Without QM, for example, with just a Newtonian World I would directly interpret my proof as a refutation of comp.

Maybe there is a typo in what you say above because if that argument actually says that "any machine betting correctly and consistently on any piece of "observable" reality, will bet that to simulate that piece of reality exactly, there is a need of simulating an infinity of computations" than I would not take it to Vegas (;-) ! This is because we can in fact, not just bet but, predict, with certainty, and simulate with arbitrary precision, the behavior of a good number "pieces of observed reality" by themselves and even verify the certainty of those predictions with a finite collection of finite algorithms which is what we do call physics (classical or quantum, theoretical or empirical) ). What we cannot do is to reproduce by any finite set of algorithms worth betting on the type of persistent built-in correlations that pairs (and trios, etc..) of these pieces of observable reality manifestly carry between them once they have been, once, part of the same piece! Even coins don't toss that way! That is where the "kabosh" is! There is no dovetailing out of it...

Also if Newtonian physics is enough to shoot down your hypothesis than it must be dead already since Newtonian physics is the correspondence limit of QM and QM is right!!! I really don't follow you here...

> OK, no one
> has built a truly quantum computer just yet but a lot of people think > they are about to do it!

I'm quasi sure they will!
And I'm quasi sure me or someone else will extract the existence of a quantum computer in the neighborhood of any "conscious" lobian machine, or refute comp. comp will provide really solid foundations for the quantum, if it is correct. In particular physical *laws* will be real general laws pertaining on all possible observers.

Well, again, I would much like to know what these "solid foundations for the quantum" are but am happy in my believe that particular(?) physical laws are *already* real general laws and indeed apply to all possible observers even without your help or George Levy's opposition!!! If I stop believing in gravity can I fly? (:-)

> [GK]
> Sure will (take it with and entire salt mine)! My point is that we > already have ways of explaining other people's experiences > on the basis of empathy or antipathy and in terms of direct causation.

Causation? Sorry but I consider such a notion as very vague (and very interesting). There are ten thousands notion of causality, and a lot of them can be studied as necessary implication: B(p->q) in some modal logic. So I consider they are at least as many notion of "causation" than there are modal logics. And there is an infinity of modal logics ...

My fault I am sorry, I should have written "interaction" instead of causation. I fully agree with you about the latter.

> Bill Clinton was found of saying "I feel your pain" and
> no one called him on that obvious lie! I can think of some numbers > that would tell me about the pain others are feeling
> (checked the price of gas today? $2.59 a gallon!!! That hurts!!!)

Quite cheap from here!

Sorry again! I feel your *bigger* pain (even if I don't own a car!)

> Seriously, I see nothing wrong with what you saying as long as you > couch it in that "faith-based" argumentation.

I think all theories are faith-based. But, yes, comp, is not only faith based, but it justifies why some part of it are necessarily faith-based, if true.

Some more than others, I would add. I catch your point but again I think this is a bit of a cop out.

> Your argument is cute and may very well be defensible that way. This
day and and age it may actually be better supported
> that way than as hard clad science, who knows?

It is hard clad science. I know of course that it could look "philosophical" because I indeed tackle a "philosophical problem". But I did actually chose purposefully special hypotheses for making the conclusion 100% testable, as it makes testable many variant of comp (like some weakening or strengthening). Many people, including Bohr, qualified the Einstein Podolski Rosen paper as "philosophical". But then (30 years later) Bell shows it to be testable (and Deutch: exploitable). My work is like EPR+BELL, although it bears on the mind body problem. The UDA part corresponds to EPR and the translation of the UDA in the language of a sufficiently rich machine theorem prover is the BELL part: I arrive to propositions as vulnerable as it is possible to be.

Again your modesty precedes you. The Bell argument, thanks largely to Clauser, Horn, Shimony and Holt, Aspect et all became an item of "experimental metaphysics" and is soon to become a major industry! And this without anyone having to sell their soul or body to a digitalist surgeon. May you be so blessed...

> [GK]
> Oh, what a pity! I was kind of bracing to see that derivation! I am
sure it would drive your point across a lot quicker.
> Oh well, I could probably give you a couple of other outrageous > hypothesis from which you could derive the whole > of physics, not constructively of course! You are the logician but > isn't it the case that from an assuredly false premise
> you can derive anything?

Oh please! If you don't know the premise is false, then by deriving anything from the premise gives in any circumstances interesting information. Take the case where I would derive the false from comp, then I would have derive a refutation of comp. (p -> f is the same as ~p). That would be something!
So non constructive proof can be interesting and informative!
Anyway, my proof *is* constructive.

I thing you got my point. The false tends to be more interesting than the true... and more heartbreaking too.

> [BM]
> The second part is a translation of that argument in the language of > the "universal machine itself". This, by the constraints of > theoretical computer science, makes the proof constructive, so that it > gives the complete derivation of physics from computer science. Of > course God is a little malicious, apparently, and we are led to hard > intractable purely mathematical questions.
> You are welcome,
> Bruno
> http://iridia.ulb.ac.be/~marchal/
> [GK]
> Oh gosh! Another let down! Well maybe those pesky Quantum Computer builders can rescue you after all one day.

Here you are right. This is actually predictable from comp. One of the quantum logics should be quantum tractable, and not classically tractable. Also, I said to much when I say the questions are intractable. I should insist on the fact that I did solve one of the main decisive question (and comp succeed the test), and that, concerning many others, I have not yet really try to solve them, but professional logician does not find them easy, so I doubt I will get them. Now, I could prove that all of them are tractable in the sense that less than a CETI project could solve them (like you can simulate a <few-bits>-quantum computer with enough classical bits.

You lost me here. Are they tractable or not? I wasn't aware that the CETI project can solve intractable problems !!!

> As
> I heard that you plan to become immortal (after a little digital > plastic surgery) you will have the time to wait for it!

It is the contrary. I plan to be mortal, but with comp this seems extremely hard if not impossible. This is the feature I dislike the most in comp. It is not clear there could be any hope of finding a way to get out. There could be a whole arithmetical Bardo Thodol. (This is already true with Everett QM). That's another reason to think about using the word "theology", perhaps.

Poor Bruno, imortel malgre soi!! And presumably "imortel qui mal y pense, aussi !" , no? Gosh, I wasn't counting on that
in my retirement plans... (;-)

Seriously for a second: I doubt that I know enough to understand all your demonstrations and arguments or judge their correctness in detail, and I am no Dr. Phil, but I have the distinct impression that you are too enamoured with your COMP
hyp to let it go. Is this possible?

Take it easy,



You too,


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