On 02 Jul 2012, at 10:28, Stephen P. King wrote:
On 7/2/2012 4:10 AM, Bruno Marchal wrote:
On 01 Jul 2012, at 20:20, meekerdb wrote:
On 7/1/2012 4:59 AM, Bruno Marchal wrote:
Except neither fortran nor Turing machines exist apart from
physical realizations.
Of course they do. Turing machine and fortran program are
mathematical, arithmetical actually, object. They exist in the
same sense that the number 17 exists.
Exactly, as ideas - patterns in brain processes.
That would contradict the Arithmetical realism, and thus Church
thesis, comp, etc.
Hi!
A big carve out of the preceding thread... We need an exact
definition of Realism!
It is the believe that the principle of excluded middle can be apply
on the arithmetical sentence. In particular the proof needs ony the
belief that phi_i(j) converge or diverge, or that the machine i
applied on j stops or does not stop, and this for any i and j.
Brent
We can implement them in physical system, but this does not make
them physical.
They are abstractions.
If you want. This changes nothing.
There is no need of step 8, here. It is just a mathematical
fact that arithmetic emulates all programs, in the mathematical
sense of "emulate".
That's a metaphorical sense.
Not at all.
"Arithmetic" doesn't act or perform anything,
Acting and performing are the metaphor here. Computation is a
purely mathematical notion discovered before the building of
physical computer. Some could even argue that the physical
reality can only approximate them.
Right. They are idealizations.
And with comp we have to define eventually notion like acting and
performing from the relation between numbers, and this is rather
easy to do.
That doesn't follow. Comp only says that we could substitute some
different physical structure for part (or all) of a brain, and so
long as the input/output functions were always
At some level,
But is this level reachable by finite means?
Yes, in the sense that the UD will, after a finite number of
computation steps (in the math sense) reach the corresponding genuine
computational state(s).
the same consciousness would be unchanged.
OK.
But how exactly would we measure this invariance of consciousness?
Like we do each time we go to the hospital, or in any life situation.
How do we deal with the parochial nature of the encodings of the
diaries that the various observers write such that we have something
like a 3p account of the experience? What I write in my diary might
be in a code that only I might understand, so how do we compensate
for this variability of language?
For the same reason we agree with Gödel's proof despite he wrote it in
german. Either use a dictionary or ask an interpreter. In this present
case, we can ask to the candidate to write W, if he self-localizes
himself in Washington, after the duplication/differentiation, and M
if not.
So comp allows that we may still need a physical realization of
the functionality.
In which case physical inactive object, with respect to a
particular computation, must be physically active. That is a
contradiction. Cf step 8.
In the case of a Mach–Zehnder interferometer we see that what
appears to be physically purely passive and inactive arms can and
does play a real and causal part such that its removal makes a
difference.
But if you simulate that with a Turing machine, you see that the arms
does play a role, you have just a multiverse. Then we do the step 8 on
that deeper simulation.
That this can be described by relations between numbers does not
entail that it is replaceable by the abstraction.
Indeed, and that is why there is a step 8.
But Step 8 makes a leap too far. It mistakes the relative
independence of computations for complete separation from physical
systems.
That is the result of step 8. To make the reasoning invalid, it is
enough to tell us that the result is surprising.
What is difficult is to get the right measure on the
computations, not to define action and performance.
I am explaining what is a computation on the FOAR list, but you
can find it also in any textbook on theoretical computer science.
No notion of physics are involved at all in the definition.
But those definitions are concerned with abstracting away the
physical,
If you want.
We do!
since the physical realization can be different for
(approximately) the same function.
You are confusing a computation with its implementation in a
physical reality. Computations have been discovered in the
mathematical reality, before we implemented them in the physical
reality. They exist independently of us, once you agree that 17 is
prime is true independently of us. And "17 is prime independently
of us" is obligatory to explain what Church thesis is, so we assume
that implicitly when saying "yes" to the doctor.
There simply is not such thing as a computation if we remove its
implicated connection to the possibility of actual physical
implementation.
That is simply false.
To remove the possibility is to disconnect it completely from the
ability to be communicated.
This is simply false, unless you postulate matter and non-comp. It is
just obvious, and trivial, that our communications do occur in
arithmetic.
They might not have the right measure, and if you prove that, then,
thanks to UDA, we will be able to say that you have refuted comp. But
that work does not exist yet.
Purely abstract statements by your definition cannot cause any
change in a physical system
With comp, they can, from the perspective of the observers.
nor be correlated with any particular configuration of brain states,
thus they are perpetually beyond our ability to apprehend them.
Comp dopes correlate consciousness with computation, so this is simply
false at the start.
It is no different than abstracting apples and oranges as fruit so
that we can add one apple to one orange and get two fruit. It
doesn't make apples and oranges the same thing.
Sure. But it makes both of them being incarnation of fruit, showing
that fruit can exist even without apple or without orange.
Nope, sorry. That simply doesn't work. Categories cannot be defined
from the inside that do not have non-labelable members. To claim
otherwise is to refute your entire result. How can you communicate
its significance if you cannot write it down?
I can write it down. I just use time and matter for that.
I don't see the problem, given that comp explain how abstract number
discover matter and can use it to communicate.
Bruno
http://iridia.ulb.ac.be/~marchal/
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