On 22 Jan 2014, at 23:16, Stephen Paul King wrote:
Dear Bruno,
On Tuesday, January 21, 2014 1:11:16 PM UTC-5, Bruno Marchal wrote:
On 21 Jan 2014, at 15:45, Alberto G. Corona wrote:
> It is a phisical definition of computation in the physical world, to
> distinguish what physical phenomena are computations and what are
not.
> I don´t care about mathematical oddities.
But nobody has found such a definition. Physical computation are only
recognized as computation in machine that we can build, from subset of
physical laws, to implement the mathematical definition.
Why not? The solution is staring us in the face. We have to
recognize that the class of Physical systems have related a class
of Representations: all of the possible measurement data of a
physical system. We can examine the measurement data and generate
simulations of the physical system in order to predict its behavior.
We call this Physics.
I don't see how this could make sense. But if it did, why don't you
use it and provide that definition of "physical computation"?
Then it is a theorem that we cannot recognize something as being a
computation, even in the arithmetical reality.
Sure, but that assumes that one is dealing with an infinite set. The
set of measurable data of a physical system is not infinite.
In which theory? As long as we don't have the theory we can't say. I
assume comp, and I show the TOE does not have to axiom anything
infinite. Elementary arithmetic don't assume infinite set.
We can build one and
recognize those we built, or we can bet that some process computes,
like when saying "yes" to a doctor. But there is no general means to
see if something is a computation or not, and this will depends in
part of we look at it.
This remark seems to have an interesting implication: that if I
examine some string of code that might happen to be a simulation of
a physical system, I will not be able to know which physical system
it is. We get universality of computation this way?
Computability is a notion discovered in math. It is related to the key
discovery of Turing (also some others) of the universal (Turing)
machine.
But this universality comes with a great price. It abstracts away
time and space and all the rest of our local reality.
But we have discovered it, and it does not abstract space and time
away, it explains the persistent illusion with all possible details.
It says only that adding an axiom at that level cannot work.
You can defend naturalism, or physicalism, and you have the right to
believe in a primitive physical universe. I am agnostic, and I have to
be, if only because we have not yet decided between Plato and
Aristotle. We are very ignorant, notably on the mind-body question.
Umm, your agnosticism does not seem very strong. You defend AR very
strongly.
No. I debunk invalid argument against it, with some vigor, perhaps.
And yes, I do tend to believe that 17 is prime.
I have offered you a sketch of a solution to the mind-body problem
and you vigorously attack it with demands for formalism that I
cannot write.
Only because you are using your informal and unclear ideas to
criticize the UDA's consequence.
What if both Plato and Aristotle are wrong?
What if you are wrong?
I do not defend computationalism. I just show that IF we assume it,
then we get a constructive and testable platonic theology, which
explains physics. And I have done a piece of the derivation and tested
it.
It does not take much to show examples of your defend, Bruno. You
are lying to yourself in claiming "I do not defend
computationalism." You will not consider any alternative.
I thought you defend computationalism also.
My case is different. I am agnostic on computationalism. But I study
its consequences. it is my job.
And, actually, I don't see any other way to even just conceive an
alternative.
If you are right on metaphysical naturalism, with a real ontological
universe, then comp is wrong. That is all what I say.
Pfft, that is a false dichotomy.
Then UDA is flawed.
It is not necessary to assume ontological primitives that have some
set of properties to the exclusion of others.
Then your ontology is amorphous. Nothing can emerge from it, without
magic.
You hold onto this dichotomy because it is your tool to defend AR.
I need indeed that 2+2=4.
>
> Computation in this sense is a manifestation of teleological
entities
> capable of maintaining his internal structure.
I can accept this as a putative truth about a notion of physical
computation, but this has not yet been defined.
Why do we need a well founded definition?
We don't.
I offer a non-well founded definition: Computation is any
transformation of Information. Information does not need to be of
physical systems; it can be of representational systems: like you
favored Sigmas and PA.
You can't change the definition. Create a new concept if you want, but
computation, or the weaker notion of computability that I need, is
well defined by Church thesis.
"reducing entropy" was
a good try, less wrong than "quantum computation" (despite here Turing
universality is verifiable), but it does not work as nature can
compute without dissipating energy (indeed quantum computers requite
that).
Where do you get that rubbish idea?
If a quantum computer dissipates energy, the entanglement will
propagate from the environment, and the quantum information will be
lost. It has been shown (by Landauer and zurel, that only erasing
information needs energy, and logicians knows since some work by Hao
Wang, in the 1950, (I think) that universal computability can be
obtained with machine which never erase memory.
(You are Insulting. I take it that you have no argument).
Quantum computation has been proven to require resources if it is to
be evaluated.
Locally. because you need to cut. But read and paste does not require
it.
Sure, the evolution of the phase is Unitary, but this holds for QM
systems in isolation. The only real example of such is the Universe
itself.
Which would be enough.
We get the Wheeler-Dewitt equation with its vanishing of time.
This go in the comp direction, although a lot of work remains to have
a clearer view on this.
> Math do not compute.
That does not make a lot of sense.
Math performs no actions on its own.
OK. Math is not even something that we can defined in math.
> Moreover it is an
> operational definition closer to everyday reality and includes all
> that is traditionally called computer science and biology (and
> sociology) within a wider physical framework.
May be. You did not provide a definition of physical computation. Nor
of "physical", which might help a skeptic like me. The only one you
gave was "reducing entropy". But it does not work. It might work for
life perhaps. It is certainly an interesting idea. But it is not
"computation". You can't change definition at will, or we are talking
about different things. The mathematical notion of computation is NOT
controversial. The physical notion of computation is not even
existing, and most attempts are controversial.
The existence of my desktop computer is obvious to me....
OK. But that "obviousness" is the mystery we can explain in the comp
theory. "obvious" is 1p, and treated in the "& p" hypostases.
Bruno
Bruno
>
> 2014/1/21, Bruno Marchal <[email protected]>:
>>
>> On 20 Jan 2014, at 21:17, Alberto G. Corona wrote:
>>
>>> Computation is understood as whatever made by a digital computer
or
>>> something that can be emulated (or aproximated) by a digital
>>> computer.
>>
>> OK. That's a good definition, and it is correct if ... we assume
>> Church's thesis.
>>
>>
>>
>>> So everything is a computation.
>>
>> Goddam! Why. Even just about what is true in arithmetic cannot be
>> emulated by any computer.
>>
>> I am afraid you might not really grasp what a computer is,
>> conceptually. See my answer to stephen yesterday, which shows wahy
>> Church thesis entails that most attribute of *machines* cannot be
>> computed by a machine.
>>
>> Or think about Cantor theorem. The set of functions from N top N is
>> not enumerable, yet the set of *computable* functions is
enumerable.
>>
>>
>>
>>
>>> That is a useless definition. because
>>> it embrace everything.
>>
>> For a mathematician, the computable is only a very tiny part of the
>> truth.
>>
>>
>>
>>
>>>
>>> Everything is legoland because everything can be emulated using
lego
>>> pieces? No, my dear legologist.
>>
>> Not veything can be emulated by a computer. few things actually in
>> usual math. Some constructivist reduces math so that everything
>> becomes computable, but even there, few agree.
>> In Brouwer intuitionist analysis he uses the axiom "all function
are
>> continuous" or "all functions are computable", but this is very
>> special approach, and not well suited to study computationalism
>> (which
>> becomes trivial somehow there).
>>
>>
>>>
>>> What about this definition? Computation is whatever that reduces
>>> entropy.
>>
>> It will not work, because all computation can be done in a way
which
>> does not change the entropy at all. See Landauer, Zurek, etc.
>>
>> Only erasing information change entropy, and you don't need to
erase
>> information to compute.
>>
>>
>>
>>> In information terms, in the human context, computation is
>>> whatever that reduces uncertainty producing useful information and
>>> thus, in the environment of human society, a computer program is
>>> used
>>> ultimately to get that information and reduce entropy, that is to
>>> increase order in society, or at least for the human that uses it.
>>
>> The UD generates uncertainty (from inside).
>>
>>
>>>
>>> A simulation is an special case of the latter.
>>>
>>> So there are things that are computations: what the living
beings do
>>> at the chemical, physiological or nervous levels (and rational,
>>> social
>>> and technological level in case of humans) . But there are things
>>> that
>>> are not computations: almost everything else.
>>
>> That is the case with the definition you started above, and which
is
>> the one used by theoretical computer scientist.
>>
>> Bruno
>>
>>
>> http://iridia.ulb.ac.be/~marchal/
>>
>>
>>
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>
>
> --
> Alberto.
>
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