Le 22-juin-05, à 13:19, Brent Meeker a écrit :
-----Original Message-----
From: Bruno Marchal [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 22, 2005 8:16 AM
To: Pete Carlton
Cc: EverythingList
Subject: Re: Dualism and the DA
Le 21-juin-05, à 21:21, Pete Carlton a écrit :
<snip>
Now, if you introduce copies to this scenario, it does not seem to me
that anything changes fundamentally. Your choice on what kind of
scenario to accept will still hinge on your desires for the future of
any persons involved. The desires themselves may be very
complicated,
and in fact will depend on lots of hitherto unspecified details such
as the legal status, ownership rights, etc., of copies. Of course
one
copy will say "I pushed the button and then I got tortured", and the
other copy will say "I pushed the button and woke up on the beach" -
which is exactly what we would expect these two people to say. And
they're both right, insofar as they're giving an accurate report of
their memories. What is the metaphysical issue here?
There are two *physical* issues here.
1) The simplest one is that if you agree with the comp indeterminacy
(or similar) you get an explanation of the quantum indeterminacy
without the collapse of the wave packet. This is mainly Everett
contribution.
I think Pete has a good point; I don't see how this bears on his
analysis of
"I".
Could you elaborate a little bit? I don't see how it could possibly
not bear on Pete's analysis of "I". I mean if Pete is right about his
"I", he should agree with Everett's notion that the probabilities are
subjective in QM.
2) The less trivial one, perhaps, is that if you agree with the comp
indeterminacy you get an a priori explosion of the number of
appearances of first person white rabbits
I don't see that either. The SWE doesn't predict that *everything*
(which is
what I presume you to mean by "white rabbits") will happen. If it did
it would
be useless.
Once you accept comp, the "explosion of rabbits" follows from the UD
Argument (UDA). Invoking the SWE here is irrelevent, unless to say that
the SWE is the only way to solve the rabbits problem. Showing this from
comp only would be derivation of the SWE from comp.
and the only way to solve
this, assuming the SWE is correct, must consist in justifying the SWE
from the comp indeterminacy bearing
But the "indeterminancy" of comp arises from equivocation about "I" as
Pete
noted.
I can agree with the use of such vocabulary.
It assumes first that there is an "I" dependent on physical structure
The "physical structure" is what makes an "I" to be able to manifest
eself relatively to some probable computation.
and then sees a problem in determining where the "I" goes when the
structure is
duplicated.
Yes.
on all computational
states/histories.
The fact that all these metaphysical problems and bizarre results are
predicted
by assuming *everything happens* implies to me that *everything
happens* is
likely false.
1) Weirdness is not falsity, but ok I am open we will get a falsity
from comp, and then comp will be refuted and that would be a giant
result.
2) "everything happens" in the comp frame, just means that the set of
all possible computations is as well defined as the set of natural
numbers. You cannot make disappear a computation for the same reason
you cannot dismiss the number "13" or the least prime bigger than
100^(100^(100^(100^(100^(100^(100^(100))))))).
I'm not sure what the best alternative is, but I like Roland
Omnes view point that QM is a probabilistic theory and hence it must
predict
probabilities for things that don't happen.
OK, but that is an ad hoc "wishful thinking" move to preserve unicity
of history. Even Roland Omnes agrees that such a move is non cartesian.
And then, in the french edition (but not in the english edition if I
remember correctly-I will verify again!) he opposes Heidegger against
Descartes in the most irrational way.
Bruno
http://iridia.ulb.ac.be/~marchal/
