RE: valuable errors

From: Gilles HENRI <>
Date: Tue, 20 Apr 1999 10:43:40 +0200

>Gilles, you are the only person I have met who does not believe in Turing,
>i.e. 'COMP' - you really need some very good arguments to deny one of the
>fundamental precepts of modern science and introduce a spirit, which is what
>you are doing.

James I am afraid that you misunderstood me if you think that I am
introducing a "spirit" which would be different from what constitutes the
whole Universe (matter or whatever it is). I am just saying that our
behaviour is so peculiar that I can see no way to reproduce it without
respecting our detailed molecular structure. Here are what I think to be my
"very good arguments".

We could start by a simpler system. Imagine that you built an "ordinary"
computer but using some special magnetic material for its memory chips.
This material has a Curie temperature around 30C (86 F). When the
temperature exceeds locally this value, the bits demagnetize, which the
computer interprets as a 0. When it falls again down this value, it takes
randomly the value 1 or 0, depending in an unknown way on the detailed spin
distribution of the memory cell. (I assume the processor itself and its
"program" are more robust and do not change in the usual conditions). The
temperature depends on a complex manner of the internal heat dissipation
AND the external conditions, temperature, wind etc...
Do you think you have built a system equivalent to a Turing machine? Of
course if the temperature never exceeds that Turing point, you have a
regular computer perfectly reproducible and equivalent to a Turing machine.
But what if the temperature raise above this point? Now to predict the
behaviour of the machine you have to know much more precisely its internal
structure to know which part of the memory will demagnetize. You may have
to know its atomic structure to know the value of the bits after
remagnitizing. Worse, if the processor drives some mechanical device that
could perturb the atmosphere like a fan, taking into account the "butterfly
effect" you may be lead to simulate the whole atmosphere, including the
whole Earth surface, to know if the weather is going to be cold or warm,
with all the uncomfortable features of chaotic systems.. This is obviously
a much more formidable task than simply reproduce a computer. Furthermore
if you try to really simulate that, you will have to build a huge computer
which will provoke its own dissipation and perturb strongly the atmosphere,
and so also your first machine...Already with such a simple device, you
have built something which is "computer like" but which cannot be
reproduced exactly. You don't need any spirit.

Now for me it's obvious that we are much more like this "computer of the
second kind" that like the "theoretical" computers (Turing machines).
Ironically our computers ARE also of this kind because their REAL behaviour
can be perturbed by external physical conditions. However, they are so
primary that exceeding the allowed temperature simply results in a crash.
Not very interesting and easily excluded by computer theory. We are a
little bit more sophisticated: we react to a larger (but not very large
indeed) range of physical conditions by adapting our behaviour, before
crashing when the temperature is really to hot, or in the absence of air,
food or water. But withing this range, the external conditions do not act
like perturbations of a "normal" state. They determine our life, our
representations, in some sense our "spirit". You cannot imagine a human
being that would never be hungry, dursty, without sexual desire, who would
not fear diseases and death : it would simply not be human.
So if you think you could reproduce a human being (in Bruno's sense, that
is an exact copy that you could consider as another version of yourself),
for example with a silicium-based computer, tell me please how you would
implement these functionalities:
* taste a new meal and tell if it tastes good or not.
* experiment a new narcotic
* react to a new virus
* meet a girl(boy) and try to charm her(him) , (all these being still
unknown when you build it!).

I need very good argument to think it is feasible without duplicating our
physical structure, or to convince me that all this is not essential to our


Received on Tue Apr 20 1999 - 01:45:40 PDT

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