Hi Bruno,

It is maybe time to change the name of the thread. But I'll get to that below.

Godfrey Kurtz
(New Brunswick, NJ)

-----Original Message-----
From: Bruno Marchal <[EMAIL PROTECTED]>
Cc: everything-list@eskimo.com
Sent: Thu, 18 Aug 2005 15:41:12 +0200
Subject: Re: subjective reality


OK. Now I agree with Lee, and many on the FOR and the Everything lists that Everett (many-worlds + decoherence already) constitutes a "solution of the measurement problem". All measurements are just interaction, and then all states are relative. As I said, it seems to me that this is even more clear in the integral formulation of QM where F = ma can be deduced from the "sum on all histories". But this is going a little bit out of topics, and is not needed to understand the comp derivation. We can come back on this latter.

Here we part company. MWI (I prefer to call it Everett's Interpretation or EQM) is NOT a solution to the measurement problem of QM but an Interpretation of Quantum Mechanics that does not lead to that problem! It does however have a tripartite problem of its own that, in my opinion, is just the measurement problem blown up. In any case what you say afterwords does not follow (from EQM or QM). There are non-interactive measurements that people have been looking into for a while now (Dicke, Elitzur-Vaidman, etc...). I am sure you guys touched on these sometime ago...

But all of this is irrelevant for my purpose at hand which is for you to commit to the proposition that "No-YD: no Bruno"! It seems to me that you are weaseling out of it but I don't quite care if you take refuge in another Everett World. That would be a cop out and I am sure you know it. I want you and I digitised IN THIS WORLD! I don't care for copies!


> In other words: if I found a way of shooting down your theory in a > way that would not obviously violate the correspondence > limit of QM , it would shot down! That is what I am suggesting above. > But do not worry because I think you are a lot better
> shot by QM.

To anticipate a little bit, I think this will be hard. From comp you can deduce quickly the qualitative "many-relative state/worlds" feature, the no-cloning theorem, the appearance of indeterminacy. I told you Newtonian physics (with a single universe-history) would cause much more problem to my approach.

I don't much care what you can deduce from COMP, Bruno. I care that COMP=YD+CT+AR and that shooting down YD would shoot down COMP. You could very well deduce from COMP my non-existence if YD is false.

> "Definition: Classical Digital mechanism, or Classical > Computationalism, or just comp, is the conjunction of the following > three sub-hypotheses:"
> after which you list three items which I will not reproduce here and
will just short as 1) YD for "Yes-doctor", 2) CT for
> Church Thesis and 3) AR for Arithmetic Realism.
> My objection is that of these three only the first can genuinely be
called an hypothesis!

Ouh la la. You are close to the 1004 fallacy (asking for more precise definition than the reasoning itself). At the start you can use the term "axioms", "postulates", "theses", "premises", "assumptions", "hypotheses", etc.. in a similar way.

I think you get my point. I am not asking for precision at all. I am pointing out that thesis and doctrines are not hypotheses tout court. These three "assumptions" do not have the same epistemic status and it is misleading to call them the same. If you don't like it, than acknowledge my pragmatics: if your point-of-view is falsifiable it should be so without compromising either CT and AR which stand very well on their own as you underscore below:

> CT, as the name indicates, is a Thesis which is most likely unprovable > but favored by overwhelming heuristic support.

Not only overwhelming supports: there is the deep conceptual argument that Kleene has discovered when he failed to refute Church's "definition" of the computable functions. The argument is the closure of the set of partial computable functions for the most transcendental mathematical operation: diagonalization. Kleene invented the vocable "Church thesis". The first to get Church's thesis is Emil Post (in the early 19-twenties).

See (perhaps later) the diagonalization posts in this list (mentionned in my web page).

> I know that there are
> some people in the southern hemisphere who think that QComputation > could produce a counterexample to > shoot it down (and perhaps it could) but you and I agree that it is


Agreed, than . In any case one unassailable counterexample would shoot down CT, deep and " Kleene" as it is (:-)

> And AR is a metaphysical position which I
> happen to subscribe but which I would never fathom to try and prove
or empirically test (nor do I have any idea
> on how to do it! Do you?)

Well, I have decided to put it explicitly, because, in front of my reasoning, some people cop out simply by saying "Ah, but you are a platonist!". So I prefer to say it at once. I agree with you it is a sort of "cop out". Now, although 99,99999999 % of the mathematician are platonist during the week, most like to pretends they are not (the week-end!).


> (1) YD is obviously independent from CT and AR



> (2) CT and AR stand no chance of being falsified empirically (or we
both like them that way, which is the same).

I give the opportunity to make comp false in more than one way. If you read the Maudlin paper, you will see that he consider the YD doctor (or equivalent) as tautologically true (unlike the functionnalist hypothesis). This is due to the fact that, unlike many older computationalist or mechanist, I put no bound on the low-levelness of the substitution level. I can say yes to the doctor provided that he simulates my brain at the chromodynamical level, including all partiocles having interacted with any other particles in the past (in which case my brain is the "physical universe" itself. My brain could be a quantum computer, without violating comp. The no-cloning theorem does not interfere.

That is actually where it gets interesting. I will have to sharpen up a bit of your YD but in ways that would not invalidate
your general use of it. More about that later.

> (3) No one that we know has been able to extract conclusions such as
yours from CT & AR without YD (right)

This is a subtle question. The *necessity* of the reversal is hardly understandable without the YD assumption. But once you grasp the necessity of the reversal, then the very derivation of natural science from computer science does not use it at all. Indeed the cognitive science's "grand-mother" is completely substituted by the Lobian Machine at this stage. So, with OCCAM razor, once enough of physics is derived, you can eliminate the grand-mother and the whole YD assumption. Some mathematician asked me to put the UDA argument under the form: motivation", and to state that my real "scientific" hypothesis are CT and AR. I find that dishonest and misleading, because, without understanding the necessity of the reversal, the interview of the Lobian machine would resemble to nothing but a little piece of pure mathematics, especially given that I have until now extracted to few real physics to really call OCCAM. All my papers introduce the grandmother (and YD), and then translate the argument in the Lobian language. But then if the logics of the observables that I have derived from comp (at the necessary place) appears to be von Neumann Quantum logics, I know people will eliminate the grandmother and the YD, for bad reasons (They want pure math, they hate cognitive science, etc.). My fear is that people take the epistemological elimination of the grand-mother (and the YD assumtion) as an ontological elimination of the first person, and nothing could be more wrong than that.
See the footnote 3. in the SANE paper, and the text

Bruno, you are weaseling out again, here! Let me ask you this in clear terms again:

Can you, Yes or No, derive your whole "grand manege" from CT and AR alone?

Because if it is a "yes" here I will give you the Oscar (and the Nobel) and let you go. I can than concentrate on being a good machine for the rest of my existence since I don't want to loose my platonic allegiances or my
heuristic acquiescence to CT.

> would you have any objections to us concentrating, from here on, on
your "YD hypothesis"?

I have no problem with that. I am willing taking full responsability for the YD hypothesis, even if at some points we can forget it, as I explain above.

Now we are talking (:-)!

> I am saying this because I actually think that it is the real > interesting and original part of your proposal

Actually I agree. But the YD hypothesis with fixed (high) level of substitution is the everyday bread of cognitive science since Plato.

So much the better, than! This way there is no chance that you can take it personally (:-)


Well, the real Doctor is Stathis Papanoiannou, in this list ;-)

Good! In that case there is a place for him a place in my story, too...

Let me comment your last post also.

> Thanks for your assent on this. I am sure that CT and AR are needed,
at some point, for your really outrageous
> conclusions. But I am sure you agree that they cannot save them if > the "Yes doctor" presumption can be shot down by itself. Right?

So, I repeat because it is a difficult point. Strictly speaking I don't need the YD (Yes Doctor) hypothesis to get physics from comp, because I just interview a lobian machine on its consistent extension. But I need it to explain why it must be so, and make explicit the link with cognitive science, psychology, theology ....

> This would save me from having to read through your Dovetail-Lob > etc... argument which
> is probably way above my head!

Please don't feel obliged to follow the argument. Do it if you really want to find what is wrong in the path toward the "outrageous conclusion". I mean that the Universal Dovetailer Argument is much more simple than some people imagine, although many remain unaware that the real difficulty is in the "movie graph" part. OK: cognitive science is not easy. For the second part, the interview of the universal lobian machine, the difficulty resides in understanding some amount of computer science, logic and logics, and quantum physics. I prefer the slow but sure path, take your time, I'm patient: you can ask me questions in my next life ;-)

> We obviously move in very different circles because I was taught by
very stubborn old strong AI types and cognoscendi
> cognitivists and I have never heard anyone argue for something like
that YD hypothesis!

Glad you notice. although the idea is defended and attacked since Plato, I am perhaps the first to tackle it in a hypothetico-deductive way. But then I'm lucky being born after Godel and Lob. (Which "I"? I don't know).

> But as you have conceded no one
> needs it to defend the old-fashioned materialist functionalism credo
that you (and I) do not subscribe to anyway.


Now tell me what I didn't anticipate from YD, I'm very curious :)
And please feel free to shot down my work in any way. It is the best way for me to illustrate the solidity of my argumentation :) ... and who knows ? perhaps you will find an error or some awkwardness. I would appreciate and acknowledge.


Thanks for the vote of confidence (;-) If I may add a personal note: Bruno, I am sure more knowledgeable people than myself have pointed out that it is hard to get accross to you because you seem so wrapped up in your "demonstration" that you express yourself in the language you develop to devise it ! That is one of the reasons I would rather take you up on your premise rather than having to read and judge the rest of your paper which I am not even confident I could. I think this is a more constructive use of my time and your patience.

What I would like to do next is the following:

1) State the YD hypothesis in a way that is both consistent with your statement and useful for my purposes. I will do that in a separate thread shortly. I need you to agree on that version, of course.

2) Once you agree I will tell you a little parable (allegory is more platonic, I guess) that illustrates the strict use of that
statement and the contradition that obtains from it.

3) After that I will tell you what that contradiction may be useful in settling a certain dispute on the question of
whether QM has anything to say about consciousness or not.

OK?  What do you say?


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