On 21 Aug, 20:49, Bruno Marchal <marc...@ulb.ac.be> wrote:
> On 21 Aug 2009, at 09:33, Flammarion wrote:
> > On 20 Aug, 00:28, Bruno Marchal <marc...@ulb.ac.be> wrote:
> >> On 19 Aug 2009, at 22:21, Flammarion wrote:
> >>> Where he says computation can happen without any physicial process
> >>> at
> >>> all. I don't see any evidence for that
> >> I am explaining this right now.
> >>> Only Bruno thinks computation trancends matter.
> >> The notion of computation and computability have been discovered by
> >> Mathematicians working around the foundation crisis of math after the
> >> discovery by Cantor and others of paradoxes in set theory.
> >> The idea is that computation should be redefined as physical
> >> computation is a very recent one, and is due to people like David
> >> Deustch and Landauer. And it does not really work as such. Deutsch
> >> "reconstruction" of the Post-Church-Turing thesis is really a
> >> different thesis.
> > Of course you can have theoretical
> > truths about computation
> > But show me something that has been computed by
> > an immaterial computer.
> A Schmidhuberian computationalist would probably answer: look around
> you. But I have explained why this is not enough, and why a prori comp
> makes the observable reality not the output of one program (but a view
> from inside from all execution of all programs).
>   I can only hope you will work on the UDA+MGA, and understand that
> "non-theoretical" truth have to be redefined as theoretical
> possibilities (consistencies) observed from inside (from some first
> person point of view).

There is no UD.

> Comp, or CTM, leads to a "many types no token" view of reality. Token
> are seen as such by being appearances from the point of view of an
> abstract subject coupled to an (infinity of) abstract computations.
> >>> CTM *implies* materialism, and the MGA doesn't work.
> >> CTM is neutral on materialism, even if many materialist use
> >> incorrectly comp to put the mind body problem under the rug. UDA,
> >> including MGA, shows why this fails.
> >> What is in MGA which does not work?
> > It's a reductio of the idea that mental states
> > supervene on computational states.
> > CTM must be cast as the claim
> > that mental activity supervenes on computational
> > activity.
> I agree. Consciousness is attached to computation (and not to
> computational states), even at the starting of the reasoning, and also
> when the physical supervenience is introduced in MGA for the reductio
> ad absurdum.
> Then, eventually, keeping CTM, and thus abandoning (weak) materialism,
> consciousness is related to, well not just a computation, but to an
> infinite sheaves of computations. Consciousness is a first person
> notion, and as such, is dependent on the first person uncertainty
> measure brought by the first person indeterminacy.
> This is why I take time to explain what is a computation, or a
> computational activity, in purely arithmetical terms. A computation is
> not "just" a sequence of computational states, it is a sequence of
> computational states related by at least one universal machine (and
> then an infinity of them, from the point of view of the conscious
> being, observably so when he/she looks below its substitution level).
> Classical physics become the study of our most probable computations,
> which emerge from the statistical interference of all computations
> going through my relevant states (the relevance being dependent of the
> observer's comp-substitution level).
> >> Thanks for quoting my sane2004 definition of comp, and showing that
> >> indeed platonism is not part of it.
> > "It is a version of Platonism"
> The wording is not important.

Maybe you could flag the wording that we are supposed
to take serioulsy.

> The point is that in the assumption of
> CTM, (CT+ the theological act of faith),  I am using that "version of
> platonism" only, which is just the idea that classical logic can be
> applied to arithmetical sentences, and in the conclusion, only, we
> have to abandon weak materialism or CTM.

Nope. Assumptions about truth don't get you a UD which is capable of
simulating me. You need
a claim about existence. You argument is either based on Platonism or

> >> Just arithmetical realism without which CT has no meaning at all.
> > The CT thesis requires some mathematical
> > claims to be true. it doesn't require numbers to actually exist
> I have never asserted that numbers actually exist. Just that they
> exist in the sense of the usual interpretation of existential
> arithmetical statement are independent of me, you, or the existence or
> not of a material world.

There is no usual interpretation, it is disputed. Formalists don't
backeards-E has any existential implications at all

> Would the two cosmic branes never have collided, and the big bang
> never occurred, the Rieman hypothesis would still be atemporally and
> aspatially true or false.

Truth and falsehood don't buy you an immaterial computer simulating me
and eveything I see.

> >> Get the feeling you have change your mind on AR. You believe that a
> >> proposition like the statement that there is no biggest prime number
> >> has something to do with physics. In which physical theory you prove
> >> that statement, and how?
> > Its truth is not  a physical truth. The existence or non-existence
> > asserted is not any kind of real existence
> OK, in your theory "real existence" = "physical existence".

There are two claim here:

"real existence" = "physical existence".
"mathemaical existence" != "real existence".

they are argued separately.

> But if the
> UDA is valid it would be better to write "consensual reality" =
> "physical reality", and ontic or basic 3- existence = arithmetical
> existence, or to abandon CTM. If UDA is non valid, it would be nice to
> point where is the error. You said that the error is in step 0,
> because I would have pretended something like "the number seven
> actually exists". My answer is that I don't see where I say so. I just
> say that the number seven exists, in the sense used by mathematicians.
> I limit my "platonism" to arithmetic to avoid the problem of
> "platonism" in set theory or analysis, and the CTM explains why
> realism on natural numbers in both necessary and sufficient.
> > I am not denying nay truths, only the interpretation of backwards-E
> > as actual existence
> I am using a fairly common notion of mathematical existence,

There is no common notion, the ontology of maths is not
a settled issue

> and I
> explain that once you say yes to the doctor, the notion of physical
> existence has to be reduced to that common notion of mathematical
> existence (actually a tiny part of arithmetical existence).
> Up to now, the only things you criticize in the UD reasoning are
> things *you* are introducing,

In the sense that your Platonism is largley implict,
and needs to be made explicit..

>and when I remark to you that it is not
> there, you say, it is implicit, but fail to show me where those
> implicit statement have been used. Then you change the meaning of
> "platonism" at every post. You define a criterium of "real" (RITSIAR)
> without ever saying if the "I" is the third person body (which we can
> doubt the existence) or the first person consciousness (which we
> cannot doubt, but can't communicate).

>From the materialist POV, the difference isn't important.

>You said that the difference is
> epistemological, but that does not answer the question.
> You said once that you accept mathematical truth, and then that the
> number seven does not exist AT ALL.


It is not some absurdity I just invented.

> You compare mathematical object with fictional character in fairy
> tales!

That's another well-know position called ficitonalism


>Do you really think that an arithmetician could write "Once
> upon a time there was an odd number dreaming  becoming an even
> number ...".

That isn't what I wrote. What I wrote was that there are sentences
which are a) true and b) mention the word "exists" but in which
"exsts" is not meant to be taken literally.

> It would help much more if you were able to say "I don't understand
> this or that in the reasoning, and give explicit reference to the
> paper or posts".

The argumetn I am actually making is that your arguemnt is either
invalid or has an imiplict premise. How am I supposed ot
point to an implicit premise.

> I would be pleased if you could stop to attribute me more than I make
> explicit. Comp is perhaps just a more precise and much more weak
> assumption than usual CTM theory which usually put the comp level very
> high. Comp is a weak precise form of CTM. And yes, I do believe that 2
> + 2 = 4, and that 7 is prime.
> Bruno
> http://iridia.ulb.ac.be/~marchal/
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