From: Marchal <marchal.domain.name.hidden>
Date: Tue Jul 13 07:11:19 1999

Hi all,

Great number of interesting and deep posts. I will try to comment some
now (actually I will answer only Chris), and others later.
For exemple SLP and Hans' discussion on
consciousness is very interesting but bears on difficult questions that
I want not to dwelve into now if only because I want to think
a little more ...
For a little "quasi-objective" theory of consciousness, look at
my (godelian) chapter 5.

>Christopher Maloney (about my post to "Romanos Avaqian"):
>Bruno, when I read your posts, I feel small! Thanks for this,
>you have swelled my reading list yet more.

I don't intend to make you feeling small and
I am sorry if I have donne so :-(

I feel that Romanos Avaqian's question is a very fundamental one.
Fair enough, Romanos' question "can the subject become an object for
himself?" gives me an opportunity to give, not *my* answer but the answer
any one will get from an interview of a self-referentially correct
modulo the "theetetic definition of knowledge". (An *avant gout* of my
chapter 5, which is self-implying independant).

The anwer is no. No subject can recognize itself as an object.

But I should mention you can get the same answer "in a self-implying
way", by using a thought experiment in which you imply yourself both in
person (subject) view and in third person view like your own duplication
thought experiment (see your URL) which shows, among other things, that
duplicated people cannot recognize themselves in their respective doubles
A machine can only BET that "itself" is an object from another machine's
(first person) point of view. Like a patient relatively to his surgeon,
or a
computationalist (practionners) in front of his classical
This reflection is also linked to Lucas-Penrose misuse of Godel's theorem,
and Benacerraf wonderfull and super-important paper (although wrong from
very beginning to the very end as Benacerraf himself recognizes): 'God,
the devil and Godel', the monist 51, 9-32, 1967.

Concerning my swelling of your reading list. I'm afraid it's only
a beginning. The mind-body problem and the everything stuff belongs
to a new (not yet named) field which is at the intersection of all fields

>Christopher Maloney (to Steve Price) :
>Ugh, I don't even want to *talk* about zombies. I find the whole
>concept patently absurd, and in a way, ethically repugnant. By
>that I mean that it seems to me awfully grandiose and anthro-
>centric to even presume that some other creature that exhibits
>all the traits of consciousness and thoughtfulness, could some-
>how not be conscious or thoughtful.

I have the same ethical aversion of the zombie notion, Chris, but ...
But sometimes for logical purpose it is useful to go beyond your
feelings. As a matter of fact the notion of zombie IS very useful
in philosophy of mind, ... if only to address the "consciousness"
problem. I agree with Steve Price's anwer to your post here.

For exemple, some philosopher of mind take the zombie as an absurd
concept (like you and me, indeed), SO if someone argue that a theory X
leads to the existence of zombie, she gives a kind of reductio ad
absurdum against the theory X.

As an illustration I think zombies are unavoidable for those who
defends the De Broglie-Bohm interpretation of QM. (Hint: AI and quantum
computing, you can help yourself with Deutsch's argument that MWI is
experimentally testable, you can find it at the Michael Clive Price FAQ

In fact those "De Broglie-Bohm" zombies are even incorporeal !
They are not made with particules !
Nevertheless most of them acts like us, including long talk on
consciousness and bodies, they makes love and children, and all this,
without consciousness and without
bodies. And all these uncorporeal bodies and unconscious talks interfere
with our real quasi-newtonian-like unique universe, full of particules !
Surely you were joking mister Bohm !
It is indeed my dislike of the idea of zombie which makes me sceptical
about any no-wave-packet-reduction-but-single-world interpretation
of either QM or COMP. Bohm's theory is a kind of cosmic solipsism and
"zombie" are useful for making that statement clear.

>Christopher Maloney (to Hal):
>Thanks for this post. Very well written. How can I get a
>copy of Maudlin's paper? Is it in English?

Yes, the paper is in English. How to get it ? You must confront
yourself with the dragon and other evils you will surely meet in
your local (university) library. The reference are in the 1989
Journal of Philosophy, page 407.
(Follow the exemple of Jacques M Mallah, Hal Finney and ...Lara Croft!).

... if the dragon is too much angry with you, tell me and I will send
you a copy :-)
By the way, I appreciate very much Hal's outline of Maudlin paper. That
will be useful.

>Christopher Maloney :
>Please explain this, if you have time. I'm sorry if you've already
>given more detail in other posts, perhaps you could point me to the
>What exactly is "the computationalist hypothesis"?

It is the hypothesis that it is in principle possible to survive
with an artificial digitalisable brain. (Note that this principle uses
a minimal amount of folk psychology for the daily interpretation of
the word "I" and "survive", and this is what I eliminate in my chapter 5).
Brain can be defined here as the portion of the universe you need,
at the level of description you need, which make the hypothesis
very weak.
You can take it simply as the hypothesis that you are a "computer".
Nevertheless comp is
logically stronger than the traditional STRONG AI thesis
(machine can think). Both COMP and
STRONG AI are stronger than the most traditional Behavioristic Thesis
(cf The Turing test). This can be proved by using ZOMBIES !.
The thesis can be made more precise with CHURCH's Thesis and some
form of (arithmetical) platonism, a weaker form of Tegmark's mathematical

You can search COMP in the archive, (or PE-OMEGA to get less answers).

>I gather from the above that "the physical supervenience thesis"
>has something to do with explaining consciousness as a software
>program, but I'm confused. I would have *guessed* that that is
>the "computationalist hypothesis", but you say that those are
>incompatible, so it can't be.

The physical supervenience thesis is the thesis that
1) there is a physical world.
2) there is consciousness (whatever it is, but it is aknowledged that it
is not typically decribable in physical or 3d-person terms).
3) that consciousness is associate (not necessarily in a causal way)
with the physical activity of the brain (or a computer with comp).

To be sure, there are other version of the supervenience thesis. It is
a not so simple notion. There is a book by KIM on supervenience, but
I don't recommand it here (to sophisticate from the philosophy of mind
point of view, and to naive from the physical science point of view).
May be more on this later. (All this IMHO, needless to say).

>Anyway, Bruno, when I read your posts, I must admit that I feel
>completely ignorant. I'm coming to this list as a software
>engineer who happens to have taken a little bit of QM, but I don't
>know anything about these heady issues of the mathematically
>rigorous computationalist theory (hell, I don't even know what to
>call it). Could you suggest any introductory textbooks on this
>topic? I am definitely convinced that your (and others on and off
>this list) approach is a valid and powerful technique for exploring
>these issues.

There are a lot of excellent introductory book. You force me to make
 difficult choices.
I guess that the best book on logic and computability, including
the modal use in godelian provability, is

Boolos G. S. and Jeffrey R. C., COMPUTABILITY AND LOGIC, 1989 (3d
Cambridge University Press.

A classical very nice and little introduction to theoretical computer
 science is:

N. J. CUTLAND, Computability, an introduction to recursive
function theory, Cambridge University Press, 1980 (repr. 1983).

A very good introductory text to mathematical Logic + Computability
is also:

MENDELSON Elliott, Introduction to Mathematical Logic, 3d ed. 1987,
Wadsworth & Brooks Inc..

But relatively to this list (and my thesis!), I think Boolos & Jeffrey is
the best you can find.

I urge everyone interested in my chapter 5 to read Smullyan penguin
book "Forever Undecided". It is one of the best simple introduction
to "self-referentially correct" reasoners.

I guess people in this list will also appreciate a lot his "the tao is
silent" and "5000 B. C". In this last book he uses
the "dream" concept to illustrate a relativistic approach to many-reality
and immortality. It is better than Platon !
I discover this recently. More on Smullyan later. (Without Doubt).

BTW, people, do you know the book by Jozef Gruska on Quantum Computing.
I find it very good ! Even on the philosophical level !
(Quantum Computing, McGraw-Hill, 1999).

In my next post I will answer/comment to Jacques M Mallah, Devin Harris,
Hal Finney, and Wei Dai ...

Received on Tue Jul 13 1999 - 07:11:19 PDT

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