# Re: what is mechanism?

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On 01 Jul 2012, at 09:57, Evgenii Rudnyi wrote:```
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```On 01.07.2012 09:38 meekerdb said the following:
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```On 7/1/2012 12:25 AM, Evgenii Rudnyi wrote:
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```On 30.06.2012 22:31 meekerdb said the following:
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```On 6/30/2012 12:20 PM, Bruno Marchal wrote:
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On 30 Jun 2012, at 18:44, Evgenii Rudnyi wrote:

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I think that you have mentioned that mechanism is
incompatible with materialism. How this follows then?
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Because concerning computation and emulation (exact simulation)
all universal system are equivalent.

Turing machine and Fortran programs are completely equivalent,
you can emulate any Turing machine by a fortran program, and
you can emulate any fortran program by a Turing machine.

More, you can write a fortran program emulating a universal
Turing machine, and you can find a Turing machine running a
Fortran universal interpreter (or compiler). This means that
not only those system compute the same functions from N to N,
but also that they can compute those function in the same
manner of the other machine.
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But the question is whether they 'compute' anything outside the
context of a physical realization?
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Personally I am not sure if they compute anything even in a
physical realization. To make my point, let us consider some device
that implements a PID controller, the equation is in Wikipedia

http://en.wikipedia.org/wiki/PID_controller#PID_controller_theory

Now let us start with the M-theory (or any other) and consider the
functioning device in this framework. There is dynamics and
evolution of superstrings, however it is unclear to me what happens
with the equation for the PID controller in this context. Does it
mean that the M-theory computes the equation of the PID
controller?
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I think that's mixing up models with the thing modeled. If there is a
device which is PID controller and it is running and controlling
something, then we have a set of equations that describes and
predicts what will happen, to a good approximation. We might program
a computer to compute what that model predicts.

M-theory is a speculative theory about matter that, if it's correct,
would be the basis of a predictive model of the behavior of the
matter making up the device which is a PID controller at a very low
level of detail (e.g. elmentary particles and fields).

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Then what is the relationship between the M-theory and the matter? How matter that must obey to the M-theory knows about it?
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How do babies use their brain? Objects described by a theory does not have to know the theory for "obeying" to the theory.
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If physicists would say that the M-theory is just a model, then I could understand.
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M-theory is just a theory. better to keep model in the logician sense.

There are three things, both for mathematical and physical realities:

The theory
The interpretation of the theory (a model)
Reality (a bet)

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Physicists usually confuse either theory and model, or model/ interpretation and reality.
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In the case of M-theory, it is even more difficult, because it is based on QM, and there are no unanimity of what QM means. Then M- theory itself is particularly hard to interpret, even assuming that QM is not problematical.
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However Hawking in Grand Design says that a physical theory is more than the model. If I have understood his 'model dependent realism' correctly, then according to him the M-theory is the reality.
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A theory is never a reality. That would be a confusion between map and reality. I guess it means that some standard interpretation of M- Theory fits with some reality that he is speculating about. If that is true, then, with comp, M-theory would be equivalent with Robinson arithmetic, which I doubt. If M-theory is the unique description of reality, and if that cannot be derived logically from Robinson arithmetic, then either M-theory is wrong, or computationalism is wrong (we have no relative substitution level). This follows from UDA.
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Bruno

http://iridia.ulb.ac.be/~marchal/

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