From: Marchal <>
Date: Sat Jul 17 07:02:23 1999

Hal wrote:

>Let me restate Marchal's example slightly, to avoid confusing talk of

> [...]

>(I would comment that it is astronomically unlikely that such an
>event could occur for a long enough period of time to be perceptable.
>Our brains are extremely complex, with billions of neurons that fire
>thousands of times a second. If the shortest period of time we can
>perceive is maybe 1/20 of a second, that is still many billions of neural
>firings. The chances that we would get that many firings occuring at
>random but with exactly the same timing that would have occured naturally
>is astronomically small. Any thought experiment which relies on such
>an event should be mistrusted, because it is so far from our experience
>and common sense. In my opinion Maudlin's paradox is more relevant.)

I will not quibble about that. The reason I was using demon is that in my
original paper (and in my thesis) I make clear how to substitute the
random lucky cosmic rays by the projection of the filmed computer, and
I can make Maudlin's move. My reasoning, like Maudlin's one never relies
on the existence of the cosmic random lucky rays.
I will certainly try to sum up all that soon.

Please read Hal's summary of Maudlin's paper and his yesterday's

The good news is that it seems that both Hal and Jacques M Mallah
understands the point.
Jacques M Mallah did indeed accept that consciousness will rely on the
presence or absence of inactive piece, but this will put arbitrariness
in any notion of physical instantiation of a computation, in the very
opposite direction of what Turing-mechanism, or computationalisme is.

Hal concludes:
>Or, in my example, if a factory fire in India can affect whether a system
>here and now is conscious, you are moving into a realm where intuitions
>about consciousness become highly suspect.

What is suspect is the idea to link consciousness to physical
activity (and to take "physical activities" for granted).

If you keep comp at this stage, you can at least suspect that
may be physical predicates are emergent from the possible computation.
(= the 'reversal').

And comp gives a frame where at this stage, finding the correct
conditional measure on the computation will provide an explanation of
machines beliefs in physical laws.

More on this latter. Unfortunately I will be again very busy next week.

Received on Sat Jul 17 1999 - 07:02:23 PDT

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