Bruno Marchal wrote:
> On 22 Aug 2009, at 21:10, Brent Meeker wrote:
>> Bruno Marchal wrote:
>>> On 22 Aug 2009, at 20:06, Brent Meeker wrote:
>>>> Bruno Marchal wrote:
>>>>> If the context, or even the whole physical universe, is needed,
>>>>> it is
>>>>> part of the "generalized" brain. Either the "generalized" brain is
>>>>> Turing emulable, and the reversal reasoning will proceed, or it is
>>>>> not, and the digital mechanist thesis has to be abandoned.
>>>> That's what makes the point interesting. Many, even most,
>>>> materialists suppose that a brain can be replaced by functionally
>>>> identical elements with no dimunition of consciousness and that a
>>>> brain is Turing-emulable BUT the "generalized brain" may not be
>>>> Turing-emulable. I personally would say no to a doctor who proposed
>>>> to replace the whole physical universe (and me) with an emulation.
>>> Do you agree that this, not only entails the falsity of CTM
>>> (computationalist theory of mind), but also on any computationalist
>>> theory of matter.
>> Yes, so long as by "computation" you mean only the Church-Turing
>> definitions of computation.
> There is no other definition of computation.
> Quantum computation are Turing emulable, and beyond this physicists
> have not defined or addressed the notion of computation. The Church-
> Turing definition is very large. And the Church-Turing thesis is the
> thesis which defines computation by Church Lambda Calculus, or Turing
> machine, etc.
The theory of computation with real numbers, i.e. geometry,
differential equations, etc. is not so well defined but it is enough
to show that CT does not encompass everythiing. In fact that is a
criticism of Tegmark's idea on which we agree - it tries to include to
>>> Your consciousness has to be related to a non computable physical
>>> process, in actuality. Quantum computer would not be universal in
>>> Deutsch sense.
>>> I am OK, with this. My point is not to convince people that comp is
>>> correct, but only that comp makes physics "coming from number
>>> to be short.
>>> Saying "no" to the doctor, is your right (even your comp justifiable
>>> right), but relatively to the reasoning it is equivalent with
>>> at step zero.
>>> So now, your mind is free to look if the reasoning is valid. No worry
>>> with the uncomfortable consequences, given that you don't believe in
>>> the initial axiom. Right?
>>> Well, you may be not interested in the consequence of a theory in
>>> which you don't believe, but you may be intrigued.
>> I am interested. I don't believe or disbelieve. Maybe the
>> "generalized brain" is Turing emulable. I'm just not nearly so
>> confident that it is as I am that my brain is emulable.
>>> Unless you believe the comp hypothesis is inconsistent? I don't think
>>> you believe this either.
>> Not inconsistent; but I have considerable empathy with Peter's view.
>> My general attitude is that "exist" is just a word to name a concept
>> we invent and we can invent different kinds of existence: physical
>> it-kicks-back existence, mathematical it's-provable-from-axioms
>> existence, etc. I may not agree that arithmetic is what's really
>> real, but I regard your theory as an interesting model and I hope it
>> leads to predicting something we don't know.
> I have no theory. Just an argument. The comp theory begins with Post,
> Turing, etc. (with precursor in the antic East, and West)
> And then I have that very simple idea to interview the universal
> machine, and to study its comp theory, and this makes it possible to
> embed all the UDA talk, including physics in arithmetic.
>> True. But the point was directed at the MGA. Part of the simulation
>> must be outside the brain - and possibly are very great deal. So
>> while it seems intuitively clear that the brain can be emulated, it's
>> not so clear that the brain + enough environment can be.
> But you see Brent, here you confirm that materialist are religious in
> the way they try to explain, or explain away the mind body problem. I
> can imagine that your consciousness supervene on something
> uncomputable in the universe. But we have not find anything
> uncomputable in the universe, except the quantum indeterminacy, but
> this is the kind of uncomputability predicted by the comp theory (and
> AUDA suggested it is exactly the uncomputable aspect of the universe
> predicted by comp).
How do you know we haven't found anything uncomputable? What would it
look like? Physics proceeds all the time assuming real numbers. Even
the idea of quantum multiverses arises from assuming that the
probability measures are real numbers. I think it can be done with
rational numbers, but that is not the worked out theory.
> So you are postulating an unknown property of matter just to make the
> comp theory false. This is really a matter-of-the gaps (cf "god-of-the
> gaps") use of matter.
> So there is a theory, may be false, which currently explains both the
> appearance of matter and consciousness, as we known them, and you are
> speculating about unknown property of matter, for preventing an actual
> This is no more science but "religion" or "wishful thinking", it seems
> to me.
> But thanks for that move, it makes me realize that "matter-of-the-
> gaps" could be used to provide some genuine way to characterize a "God-
> of-the-gaps" use of matter for explaining the mind-body problem away.
> Primitive matter is a speculation which satisfies the need of
> physicalism, but I don't know any other function it could have.
It's not so much physicalism but rather explaining why *this* happens
and *that* doesn't. I'm not convinced by the Born rule has been
justified in spite of many attempts to derive it from simpler axioms.
I hope that your "argument" may provide such a justification - in
which case I will be impressed and become much less dubious of AR.
But really my opinions are irrelevant. Let's see where your
> really like Bohm's particle or Bohr collapse to prevent quantum
> mechanics to work in the macroscopic: a change of a theory to respect
> a philosophical or religious conception we can have, and this despite
> a total lack of evidence.
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