On 11 Feb 2011, at 19:10, 1Z wrote:

On Feb 10, 1:24 pm, Bruno Marchal <marc...@ulb.ac.be> wrote:
On 09 Feb 2011, at 16:49, 1Z wrote:

On Feb 8, 6:17 pm, Bruno Marchal <marc...@ulb.ac.be> wrote:
On 07 Feb 2011, at 23:58, 1Z wrote:

On Feb 7, 6:29 pm, Bruno Marchal <marc...@ulb.ac.be> wrote:

Everything is fine. You should understand the reasoning by using
the formal definition of "arithmetical realism",

You reasoning *cannot* be both valid and ontologically
neutral because it has ontological conclusions.


Wrong about what?

You were wrong on the idea that an argument cannot be valid and
ontological. It is enough that the premises have ontological clauses.

So which is the ontological premise? You don't say
that Platonism is an explicit premise. But it isn't
a corollary of CT either.

CT needs arithmetical platonism/realism. If you believe the contrary, could you give me a form of CT which does not presuppose it?

See my papers.

That is just what I am criticising. You need the ontological
premise that mathematical entities have real existence,
and it is a separate premise from comp. That is my
response to your writings.

The only ontology is my conciousness, and some amount of consensual
reality (doctor, brain, etc.).

If I agree only to the existence of doctors, brains and silicon
the conclusion that I am an immaterial dreaming machine cannot follow

Then you have to present a refutation of UDA+MGA, without begging the question.

It does not assume that physical things
"really" or primitively exists, nor does it assume that numbers really
exist in any sense. Just that they exist in the mathematical sense.

There is no generally agreed mathematical sense. If mathematical
anti-realists are right, they don't exist at all and I am therefore
not one.

Mathematicians don't care about the nature of the existence of natural numbers. They all agree with statement like "there exist prime number", etc.

Read a book on logic and computability.

Read a book on philosophy, on the limitations of
apriori reasoning, on the contentious nature of mathematical ontology.

You are the one opposing a paper in applied logic in the cognitive and
physical science. I suggest you look at books to better see what i am
taking about.

You are the one who is doing ontology without realising it.

On consciousness. Not on numbers, which I use in the usual mathematical or theoretical computer sense. The reasoning is agonstic on God, primary universe, mind, etc. at the start. The only ontology used in the reasoning is the ontology of my consciousness, and some amount of consensual reality (existence of universe, brains, doctors, ...). Of course I do not assume either that such things are primitoively material, except at step 8 for the reductio ad absurdo. Up to step seven you can still believe in a primitively material reality.

Boolos and
Jeffrey, or Mendelson, or the Dover book by Martin Davis are
It is a traditional exercise to define those machine in arithmetic.

I have no doubt, but you don't get real minds and universes
out of hypothetical machines.

You mean mathematical machine. They are not hypothetical. Unless you
believe that the number seven is hypothetical,

I do. Haven't you got that yet?

I did understand that seven is immaterial. But I am OK with seven being hypothetical. It changes nothing in the reasoning.

in which case I get
hypothetical minds and hypothetical universes.

I am not generated by a hypothesis: I generate hypotheses.

Confusion level. If you suppose a TOE you are supposed to be explained by that TOE. In that sense you are generated by an hypothesis, even if your own consciousness here and now is plausibly not an hypothesis.

It is not a big deal to
accomodate the vocabulary.

Recently Brent Meeker sent an excellent reference by Calude
illustrating how PA can prove the existence of universal machine (or

Oh good grief....it can only prove the *mathematical* existence. If
mathematical "existence" is not real existence, I am not an immaterial

Comp can explain why mathematical machine believes that they are made
of stuff. If you have an argument that stuff is primary, then you have
an argument against comp.

That doesn't follow. An immaterial machine might believe it is
but so might a material machine. So arguing that matter is prmiary
has no impact on comp.

Comp will imply that such a primary matter cannnot interfer at all with your consciousness, so that IF comp is correct physics has to be reduced to number theory, and such a primary matter is an invisible epiphenomena. Occam does the rest.

Not against the validity of the reasoning.

what is at is the side of formalism
that says maths is ontologically non-commital game playing.

That is not formalism. That is conventionalism (in math).

So you say. I have quoted a source saying they are the same

A pre-Gödelian reference. Kant.

This has
been refuted.

By whom?

By mathematical logicians since Gödel. Perhaps before by Dedekind.
A weak form of formalism can subsist, but conventionalism does not. Arithmetical reality kicks back, and cannot be captured completely by *any* theory.

We know today that we have to posit numbers to reason on
them. We don't have to posit their "real" existence (whatever that
means), but we have to posit their existence.

Unreal existence is not enough to support the conclusion
that I am a number

Certainly. That is why I give a detailed argument. You don't address it by criticizing its starting definition, by attributing too much metaphysical sense to arithmetical realism.



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