Re: The Meaning of Life

From: Bruno Marchal <>
Date: Tue, 2 Jan 2007 13:30:04 +0100

Le 02-janv.-07, à 04:20, Stathis Papaioannou a écrit :

> Bruno Marchal writes:
>> Le 31-déc.-06, à 04:59, Stathis Papaioannou a écrit (to Tom Caylor):
>> > Of course: questions of personal meaning are not scientific
>> questions. > Physics may show you how to build a nuclear bomb, but it
>> won't tell > you whether you should use it.
>> But Physics, per se, is not supposed to answer this.
>> Socio-economics could give light, as could "computer simulation of
>> nuclear explosion in cities ...".
>> And some (still putative) theory of ethics could perhaps put light on
>> that question too. Well, the ultimate decision is a problem for the
>> "president" .... But the president and its advisers could consult
>> some decision theory ... perhaps.
> No, those theories won't answer the question of whether you should use
> the bomb either. Suppose your theory says something like, "if you wish
> to save a lives by taking b lives, where a>b, then you should use the
> bomb". The scientific part of this theory involves demonstrating that,
> in fact, use of the bomb would save a lives by taking b lives. But
> this does not tell you whether you should actually use the bomb.
> Neither would an ethical theory like utilitarianism tell you what to
> do: it might confirm that according to the theory it is the right
> thing to do, but utilitarianism cannot tell you that utilitarianism is
> "right". In the end, what is "right" is an irreducible personal
> belief, which you can try to change by appeal to emotions or by
> example, but not by appeal to logic or empirical facts. And in fact I
> feel much safer that way: if someone honestly believed that he knew
> what was "right" as surely as he knew 2+2=4, he would be a very
> dangerous person. Religious fanatics are not dangerous because they
> want to do evil, but because they want to do good. The number of
> people killed in the name of God vastly outnumbers the number killed
> in the name of Satan.

I completely agree with you. I have just interpret your "should" not as
a ethical "should" but as one relative to an ethical decision already
done (by the human, mister president or whatever).
I think you knew we do agree on this. It is what I sum up saying that
there is no normative theory of ethics. A theory of ethics have to be a
sort of meta-theory.
I guess I was unclear.

>> > Where I think I disagree with you [Tom] is that you seem to want to
>> > reduce the irreducible and make values and personal meaning real
>> world > objects, albeit not of the kind that can be detected by
>> scientific > instruments, perhaps issued by God. But in proposing
>> this you are > swapping one irreducible entity extremely
>> well-grounded in empirical > evidence (I know I'm conscious, and I
>> know that when my brain stops so > does my consciousness) for another
>> irreducible entity with no > grounding in empirical evidence
>> whatsoever.
>> I agree that you know you are conscious. Well, I don't know that but
>> I have good evidences and hope. But I don't see any evidence that
>> when your brain stops so does your consciousness. I can understand
>> the belief (not even knowledge) that when your brain stops relatively
>> to mine (in case we share an history), then so does the possibility
>> of your consciousness to manifest itself relatively to me; but no
>> more.
>> Actually what does mean the expression "my brain stops". In all
>> universe? all multiverses, all computational histories ...
>> You have to be precise which theory you are using when relating some
>> 3-me (like "my brain") and some 1-me (like the knower, the conscious
>> "I").
>> I agree with some critics you make with respect to Tom Caylor notion
>> of personal God, but sometimes, it seems to me, you have a conception
>> of reality which could as criticable as Caylor's one. Err... i see
>> your particular point is valid though, but you are using misleading
>> images with respect to the consequence of mechanism (I guess you are
>> aware but that you want to remain short perhaps).
> It gets cumbersome to qualify everything with "given the appearance of
> a physical world". As I have said before, I am not entirely convinced
> that comp is true,

Nor am I. (Remind that no machine can, from its first person point of
view, be "entirely convinced" that comp is true. Comp is an axiom for a
theory, and the beauty of it is that comp can explain why it has to be
a guess. The "yes doctor" has to be an act of faith. It is

> precisely because because such ideas as a conscious computation
> supervening on any physical process

This does not follow at all. We have already have some discussion about
this and since then I have a more clear-cut argument. Unfortunately the
argument is based on some result in mathematical logic concerning the
distinction between real numbers and integers. We can come back on this
in another thread. For a logician there is a case that "real number"
are a simplification of the notion of natural number. An identical
polynomial equation can be turing universal when the variables are
conceived to belong to the integers, but is never turing universal when
the variables belong to the reals. Well, a case can be made that the

> or on no physical process may be considered absurd.

This would be fair enough in case the idea that consciousness
supervenes on physical processes was not absurd in the first place. In
all your post you do assume comp. For comp to be false you have to
assume actual physical infinities and give a reason why consciousness
supervenes on that. But in some reasoning it seems clear to me you talk
life if comp is true, when referring to the functional role of
neurotransmitters, the fact that slight change in the brain are
permitted, etc.

> It is quite possible, for example, that there is something special
> about the structure of the brain which leads to consciousness, and a
> digital computer will not be able to copy this, even if it copies 3rd
> person observable behaviour. Against that idea is the question of why
> we didn't evolve to be zombies, but maybe we would have if nature had
> electronic circuits to play with.

You are saying that zombie are possible if comp is false. I can agree.
Actually I believe that comp entails the existence of a notion of local
zombie (which can make you believe that they are conscious during a

> If I had to guess between comp and not-comp I don't think I could do
> better than flipping a coin.

Comp is my working hypothesis, and I tend to consider that arguing for
or against comp is a bit of a waste of time (especially given that comp
is undecidable for machines).
Still I am astonished that you would flip a coin on that matter. Comp
is just the statement that "I" am turing emulable at some level. Even
if we have to emulate the quantum state of the entire galaxy (some
"generalized brain") comp remain true unless we have both:
- my brain = the "complete physical" description of the galaxy
- the "object" galaxy is not turing emulable
Now comp predicts the existence of "appearance of physical things which
are not turing emulable" (confirmed by the existence of quantum
flipping). But attaching consciousness to that non turing emulable part
leads nowhere. That is why Penrose is forced to put quantum mechanics
and relativity in doubt when he wants to keep both materialism and a
physicalist theory of mind.

Personally I don't think more incredible to believe that consciousness
supervenes on a physical brain, a block universe, or on collections of
relations between numbers. Actually I think consciousness is
immaterial, so that I find harder to attach it to something physical
(dualisme). And then physics just provides relation between numbers.
"matter" is a useful fiction for animals survival, an oversimplified
view of an average on the set of our most accessible neighborhoods.

Matter is like the wave packet reduction in QM, except that "nature"
has programmed us with such a "simplified theory" since a long time,
but we must, as scientist digging on fundamental questions, remind us
that there is no evidence (at all) that Matter (primary matter) exist.
On the contrary, we do have (even if first personal) strong clues that
consciousness, persons, machines, and numbers exist, even in some
sharable sense.

Modern "pure science" (as opposed to engineering) has begun with the
idea that what we see and measure could be the shadow of the shadow of
the shadow of something which *perhaps* is. And to be short (and
provocative) I would say that "pure science" has stopped when Aristotle
successfully (thanks to the Christians mainly) did come back with the
"demagogical" idea that, after all, what exist is what we see ...

(All this is not related to ethics, but belong to some "ontic" thread).


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Received on Tue Jan 02 2007 - 12:49:55 PST

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