On 29 Jun 2015, at 12:27, Bruce Kellett wrote:
Bruno Marchal wrote:
On 29 Jun 2015, at 01:37, Bruce Kellett wrote:
Bruno Marchal wrote:
On 26 Jun 2015, at 04:19, Bruce Kellett wrote:
Bruno Marchal wrote:
On 25 Jun 2015, at 14:27, Bruce Kellett wrote:
My contention is that the body (and the rest of the world) is
essential for a satisfactory account of personal identity.
I can understand, but that remains possibly true
phenomenologically. Unless you explain me why you use your
theory to refuse a brain transplant to a kids who will die
without?
A brain transplant means replacing one physic brain with another
physical brain. I think you need to explain why we need a
transplant -- why not just replace the brain with the
appropriate universal number tattooed on the forehead?
because in that case (admitting some sense in it) would not save
your relative manisfestation locally.
Personal identity is not just a matter of memories.
Right, and that is clear from the AUDA definition. But for UDA,
personal memory is enough to get the reversal.
You have not *derived* any reversal at any stage -- you have only
ever asserted or assumed it.
The reversal follows logically from COMP + ROBUST-UNIVERSE at step
seven. If not, ask me what you don't understand.
The trouble is that there is a simpler and more believable
interpretation of the UD available. Let us go to a robust universe
or, more particularly, the UD as run in Platonia or arithmetic.
At step seven, we use the concreteness of the UD. But let us see.
You say that this then runs all possible computations and, indeed,
runs any finite computation indefinitely often.
It runs also the infinite computations infinitely often. OK.
Let us accept this for the moment.
This is provable. But OK.
Then there is a computation that instantiates the entire observable
universe, from the big bang to indefinitely far into the future.
Not necessarily. The observable is eventually given by the limit on
all non stopping computations, and that limit might be computable, or
not. We don't know what is the case.
I do agree, yet, that all computations approximating the physical
universe are run by the UD.
This then gives the entire universe. The computation may be
repeated many times, but by the identity of indiscernibles, those
repetitions are just the same universe.
Assuming that the limit above is computable, which can hardly be the
case (unless my generalized brain is the entire universe, which I
doubt, but of course, we don't know, although the QM/MWI suggests
empirically that it is not the case).
There will be computations that differ from the one giving this
universe to greater or lesser degrees, so these give neighbouring
universes that differ in these degrees. Actually, this is just the
level 1 multiverse of Tegmark. Given eternal inflation, there are an
infinite number of O-regions (observable universes) sharing our
basic physics. The idea is that there are only a finite number of
possible histories for these O-regions, so any history is repeated
indefinitely often. And for any history, all close and not-so-close
copies are also frequently repeated. This is just what comes out of
the UD as well as these physical theories.
More or less OK.
Computations also exist that correspond to less than complete
universes, or give inconsistent physics, or whatever. The very
limited computation that gives an individual consciousness or
conscious moment is insignificant in the bulk, and because of the
problem of consistent continuations, those "moments" have zero
measure. So we do not have the situation of "reversal", where the
physics is derived from the continuations of these moments. The
physics is given by the extended computations that create entire
observable universe.
But if the physical universe run the UD, to predict (conceptually) if
this apple will fall on the ground, I must look at all computation
going through my current state (where I look at the apple still in my
hands). How would you do? That is obligatory by the (even just local)
FPI.
In this situation, physics is to be done in the usual way --
observation, experimentation and the development of corrigible
theories.
Nobdiy will ever arguye that experiemental physics should be done in
other ways. Theoretical physics and fundamental physics will change
but just by elimination of redundant hypotheses, and by the abandon of
primary matter (sometimes already abandoned by physicists themselves).
"Questioning the machine" will never go anywhere because finite
continuations of local conscious calculations are not sufficiently
coherent.
On which view? That is true for []p, but false for []p & <>t.
Are you not suffering of some Dunning-Kruger symptoms? If you have a
proof that finite continuations of local conscious calculations are
not sufficiently coherent, then you could refute comp. Do it, then.
It is only within the larger computation that any consistent physics
can emerge.
The infinitely many one, yes, but this works only if it wins the UD
measure, and change nothing in the fact that physics is determined by
the measure on all computations.
This means that physics is completely computable -- Turing emulable.
But that is what quantum mechanics in the Everettian interpretation
tells us. Unitary evolution preserves (quantum) information, and is
completely calculable.
Which suggests that the quantum part of QM is part of the winner
program for the measure, but this remains neutral on the hamiltonian.
You have difficulty extracting physics from your theory because you
are looking in the wrong place.
The point is independent of the extraction. The UDA point is that the
extraction exists, and can be find by interviewing the machine.
Then, I don't know to which difficulty you allude too.
On the contrary I am amazed of what is already derived.
Now, I am not claiming that the above outline is correct, or that I
even believe it. But it is a more coherent interpretation of the
scenario you paint through the UDA than the arguments you give.
I have not seen your point. The reversal still occurs at step 7,
assuming a primitive robust universe. If the entire physical universe
is computable, you still need to prove this and justify its winning
measure ability to solve the mind-body problem.
Given that there are alternative, more plausible interpretations of
the idea that all computations are present in arithmetic, I do not
feel in the least constrained to accept your particular view.
Nice try, but you made statements without proof (see above), and I
don't see where in your argument you compare the comp predictions and
the empirical predictions, except by your invocation of a "real
physical universe", which begs the question and use implicitly some
non Turing emulable ability of matter to select a computation.
Bruno
Bruce
Then in step 8, the assumption "ROBUST-UNIVERSE" is replaced by the
usual weak form of Occam razor, as we can never prove something
about reality without invoking it.
Why don't you ask question instead of talking like you find a flaw?
If you find a flaw tell us precisely in which step please.
Apparently you still have a problem with step 7, before MGA, as
there is a reversal at step seven. Don't you see it? How do you
predict the result of an experience of physics in step 7?
--
You received this message because you are subscribed to the Google
Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
http://iridia.ulb.ac.be/~marchal/
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
