Many Pasts? Not according to QM...

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Patrick Leahy

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May 18, 2005, 12:25:21 PM5/18/05
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I've recently been reading the archive of this group with great interest
and noted a lot of interesting ideas. I'd like to kick off my contribution
to the group with a response to a comment made in numerous posts that a
single observer-moment can have multiple pasts, including macroscopically
distinct pasts, e.g. in one memorable example, pasts which differ only
according to whether a single speck of dust was or was not on a
confederate soldier's boot in 1863.

Does anybody believe that this is consistent with the many-worlds
interpretation of QM? If so, please think again! Even such an apparently
minor change is sufficient to split the universal wave function into two
distinct branches (i.e. branches peaking in vastly-separated regions of
configuration space), which can recombine with probability effectively
zero. The reason for this is "decoherence" in the technical sense used by
Zurek and others.

To counter one obvious rejoinder, I'm not denying that micro-histories can
recombine, as in the two-slit experiment. Rather, decoherence ensures that
states with macroscopic (or even mesoscopic) entropy spread their
information so effectively that it is practically impossible to erase it
("practically" in the sense that even the entire resources of the universe
would be insufficient, as emphasised by Omnes).

Of course, many of you (maybe all) may be defining pasts from an
information-theoretic point of view, i.e. by identifying all
observer-moments in the multiverse which are equivalent as perceived by
the observer; in which case the above point is quite irrelevant. (But you
still have to distinguish the different branches to find the total measure
for each OM).

======================================================
Dr J. P. Leahy, University of Manchester,
Jodrell Bank Observatory, School of Physics & Astronomy,
Macclesfield, Cheshire SK11 9DL, UK
Tel - +44 1477 572636, Fax - +44 1477 571618

Quentin Anciaux

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May 18, 2005, 12:28:46 PM5/18/05
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Le Mercredi 18 Mai 2005 17:57, Patrick Leahy a écrit :
>
> SNIP

>
> Of course, many of you (maybe all) may be defining pasts from an
> information-theoretic point of view, i.e. by identifying all
> observer-moments in the multiverse which are equivalent as perceived by
> the observer; in which case the above point is quite irrelevant. (But you
> still have to distinguish the different branches to find the total measure
> for each OM).

Hi,

I thought of Observer Moment as containing the observer... What is the meaning
of an OM (the same) which spread accross branches ? If you start by the
assumption that OM are fundamental, then a "branch" is an OM. Or a branch is
a consistent succession of OM ?

If the split forever is correct, then does a consciousness spread accross all
those branch where the OM is in ? or just in one branch, and in other
branches with the same OM, this is not the same consciousness ? If the later,
why can it be said that it is in fact the same OM ?

I apologize for the apparent mix of questions, and the "bad" english... Hope
you understand what I wanted to say ;)

Quentin Anciaux

Patrick Leahy

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May 18, 2005, 2:09:17 PM5/18/05
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On Wed, 18 May 2005, Quentin Anciaux wrote:

> Le Mercredi 18 Mai 2005 17:57, Patrick Leahy a écrit :
>>
>> SNIP
>>
>> Of course, many of you (maybe all) may be defining pasts from an
>> information-theoretic point of view, i.e. by identifying all
>> observer-moments in the multiverse which are equivalent as perceived by
>> the observer; in which case the above point is quite irrelevant. (But you
>> still have to distinguish the different branches to find the total measure
>> for each OM).
>
> Hi,
>
> I thought of Observer Moment as containing the observer... What is the
> meaning of an OM (the same) which spread accross branches ? If you start
> by the assumption that OM are fundamental, then a "branch" is an OM. Or
> a branch is a consistent succession of OM ?
>

I'm also learning a new "language" here as well, so forgive me if I got
it wrong. I was trying to put the best "spin" I could on the idea of
multiple pasts. Personally I'm not sympathetic to the OM concept in the
first place, except as a useful device for anthropic calculations.

By a "branch" I mean a branch of the wave function (Psi for short), which
in MWI does literally have a branching structure in (configuration space +
time). This is absolutely not an OM: for one thing, a branch is extended
in time. Also, each branch of Psi describes a history for all the
observers in the universe (not to mention all the non-self-aware bits),
and hence contains (>>?) billions of OM at any given time. And of course a
different OM for each observer at each moment.

> If the split forever is correct, then does a consciousness spread
> accross all those branch where the OM is in ? or just in one branch, and
> in other branches with the same OM, this is not the same consciousness ?

This is really a matter of definition, I think. Is there a distinction
between "consciousness" and "OM" ? I would say yes but I suspect many
here would disagree. From my point of view, I'd prefer to say that each
observer (and her consciousness) inhabits a specific branch and has only
one past, even if it is indistinguishably different from that of a copy in
another branch.

> If the later, why can it be said that it is in fact the same OM ?
>

I'm with you. But if you take OM as fundamental, as some here do, you
might prefer to re-sort the OMs scattered throughout the multiverse so
that all identical OMs go into one "pot"; then you can choose to call this
pot a single OM with a greater or lesser weight. In which case it is
probably legitimate to talk about these having multiple pasts, though in
another sense they have no past (they are self-contained moments!), only a
memory of one (which is *not* multiple, by definition).

Hal Finney

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May 18, 2005, 4:38:08 PM5/18/05
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Patrick Leahy writes:
> I've recently been reading the archive of this group with great interest
> and noted a lot of interesting ideas. I'd like to kick off my contribution
> to the group with a response to a comment made in numerous posts that a
> single observer-moment can have multiple pasts, including macroscopically
> distinct pasts, e.g. in one memorable example, pasts which differ only
> according to whether a single speck of dust was or was not on a
> confederate soldier's boot in 1863.
>
> Does anybody believe that this is consistent with the many-worlds
> interpretation of QM?

First, welcome to the list.

You are right that in the strict MWI, if we define an observer-moment
to be restricted to one branch, then observer moments do not merge.

I might mention that there is some disagreement among aficionados of
the MWI as to what constitutes a branch. Some reserve the concept of a
unique branch, and branch splitting, to an irreversible measurement-like
interaction, as you are doing. Others say that even reversible operations
create new branches, in which sense it is OK to say that branches can
merge. David Deutsch does this, for example, when he says that quantum
computers use the resources of many branches of the MWI (and hence prove
the reality of the MWI!).

However, particularly as we look to larger ensembles than just the MWI,
it becomes attractive to define observers and observer-moments based
solely on their internal information. If we think of an observer as
being a particular kind of machine, then if we have two identical such
machines with identical states, they represent the same observer-moment.

>From the first-person perspective of that observer-moment, there is no
"fact of the matter" as to which of the infinite number of possible
implementations and instantiations of that observer moment is the real
one. They are all equally real. From the inside view, the outside is
a blur of all of the possibilities.

If we apply that concept to the MWI, then we retrieve the concept of an
observer-moment that spans multiple branches. As long as the information
state of the OM is consistent between the various branches, there is
no fact of the matter as to which branch it is really in. That is the
sense in which we can say that observers merge and that observer moments
have multiple pasts.

Hal Finney

Patrick Leahy

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May 18, 2005, 5:10:45 PM5/18/05
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On Wed, 18 May 2005, Hal Finney wrote:

>> Does anybody believe that this is consistent with the many-worlds
>> interpretation of QM?
>
> First, welcome to the list.

Thanks!

<SNIP>


>
> However, particularly as we look to larger ensembles than just the MWI,
> it becomes attractive to define observers and observer-moments based
> solely on their internal information.

<SNIP>

I wondered if that's what was meant... hence the last para of my
message, and my comments in my follow-up to Quentin Anciaux. But you
explain it better (in a bit I snipped!).

Mind you, I don't understand why you find your definition "attractive". It
would be pretty confusing for physicists to say "there's only one
electron", even though they all are absolutely identical.

And also, as I mentioned to Quentin, if you are going for such a radical
first-person perspective, an OM really *has* no outside so it is a bit
misleading to talk of "pasts" at all.

regards,
Paddy

George Levy

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May 19, 2005, 1:04:48 AM5/19/05
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Hi Patrick,

Let me also welcome you to the list.
I agree with Hal that there are several schools of thoughts regarding many pasts. I believe that a crucial ingredient in accepting the many past concept is the concept of indiscernibles by Leibniz. If two objects are indiscernible then they are one and the same object. Similarly, if two OMs are indiscernible then they are one and the same. Thus if two past OM's lead to two identical present OM's then these two present OM's are one and the same OM. Hence this present OM has two pasts.

Following this reasoning, OM's in the past present and future are a huge network rather than on a huge branching tree.

Note that the whole issue hinges very much on a perception of indiscernibles. The story becomes more complicated if we ask the question whether the concept of indiscernible is first person or third person. I am of the opinion that third person is essentially only an illusion caused by the sharing of almost identical frames of references, and that first person perspective is the only perspective that matters.

Assuming first person, we see that not only we have different pasts and futures but that each one of us has different pasts, presents and futures. In this merging and splitting network, some of us may reach identical OM's. When we do we become the same person for a short "time." Soon after we split again.

George

Stathis Papaioannou

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May 19, 2005, 4:20:13 AM5/19/05
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Regarding observer-moments:

This is a good question because it provides an opportunity to explain the
reason behind the idea of observer-moments (OM). Essentially, OM is the
minimum unit of conscious experience. It is sometimes taken as being
instantaneous, but if this presents theoretical problems, it can be
redefined as observer-second or whatever you think the minimum should be. An
individual's identity, or conscious experience over a period of time, is
then constructed from a series of OM. "Constructed" in this context does not
necessarily mean that any particular physical process takes place to string
the OM's together. Most familiarly, there *is* a physical process doing just
this: namely, the OM's follow (more precisely, supervene) in sequence from
the electrochemical reactions in an individual brain. However, and this is
the crucial insight, there is no reason to think that functionally the same
multi-OM conscious interval cannot occur if the OM's are separated widely in
time, space, or even across branches of the MW which can have no physical
connection. This is because the OM's are "connected" only by virtue of their
information content, which can transcend time, space, or being in different
universes. This does not necessarily mean that any actual information
transfer has to take place; it suffices that the relationship between the
widely separated OM's is the same as it would have been if the information
transfer had taken place in the usual way, such as in a functioning brain.
For example, if I have the thought, "I am counting 1,2,3 bananas..." and by
chance somewhere else in the multiverse there arises a sentient computer
program which believes it is me, has the same memories as me up to that
point, and continues "...4,5,6 bananas", then that latter computer program,
although it has no physical connection to me and indeed could not even have
possibly obtained any information from me in this universe, nevertheless
will experience being me in the same way as if I had continued counting
bananas in this universe in the usual manner.

A consequence of the above is that it does not make sense to talk about
where your consciousness "really" is, or whether it really is the "same"
individual accross different instantiations, because a multi-OM conscious
interval can be defined any way you like. You can decide that if an OM
deviates sufficiently from some arbitrary standard, then that is a new
individual. You can also have multiple instances of the "same" individual
running in the same or different universes. The only absolute is the OM, and
everything else is a construct.

Superficially, this may all seem a bit strange: why bother? The reason I was
driven to this view was from consideration of the philosophical problem of
personal identity. It may seem straightforward that you are the same person
as you were last year, but every atom in your body may be different, in a
different configuration, and giving rise to different memories and other
mental properties. (It may seem that at least the latter two are identical,
but the similarity over even a relatively short time period is only
approximate). Add to this the result of multiple thought experiments: what
if your future self from next week came back in time; what if you were
exactly duplicated via a Star Trek-type teleporter; what if you were
resurrected in Heaven; what about the multiple near-exact copies of you in
other branches of the MW; what about mind uploads; and so on. The only way
to avoid the paradoxes of multiple identities is to accept that every
apparent "identity" is a separate entity, and moreover that every moment of
every apparent identity is a separate entity. This leads directly to the
concept of the observer-moment, and the paradoxes disappear.

--Stathis Papaioannou

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Stathis Papaioannou

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May 19, 2005, 7:30:55 AM5/19/05
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Patrick Leahy wrote:

[quoting Quentin Anciaux, who responded to Patrick's original post]

Observers and observer-moments are not incompatible ideas. OM's are simply
the moments that make up an observer's stream of consciousness. You might
reasonably argue, if OM's cannot stand in isolation, but are always grouped
together in a particular instantiation of an observer (debatable, but let's
grant this is so), then isn't the idea of OM's a needless complication,
compared to the traditional concept of an observer who persists through
time? The short answer is that it is very difficult to come up with a
consistent definition of an observer which covers all eventualities
(persistence through time, multiple copies in the same or different
universes, upload to a computer, etc.), and the idea of OM's allows you to
define an observer on the fly, aknowledging that the idea is ultimately
arbitrary. See my recent thread on "observers and observer-moments" for a
slightly longer reply.

--Stathis Papaioannou

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Saibal Mitra

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May 24, 2005, 7:28:16 PM5/24/05
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----- Oorspronkelijk bericht -----
Van: "Patrick Leahy" <j...@jb.man.ac.uk>
Aan: <everyth...@eskimo.com>
Verzonden: Wednesday, May 18, 2005 05:57 PM
Onderwerp: Many Pasts? Not according to QM...


> Of course, many of you (maybe all) may be defining pasts from an
> information-theoretic point of view, i.e. by identifying all
> observer-moments in the multiverse which are equivalent as perceived by
> the observer; in which case the above point is quite irrelevant. (But you
> still have to distinguish the different branches to find the total measure
> for each OM).

This is indeed my position. I prefer to define an observer moment as the
information needed to generate an observer. According to the ''everything''
hypothesis (I've just seen that you don't subscibe this) an observer moment
defines its own universe. But this universe is very complex and therefore
must have a very low measure. It is thus far more likely that the observer
finds himself embedded in a low complexity universe.


One of the arguments in favor of the observer moment picture is that it
solves Tegmark's quantum suicide paradox. If you start with a set of all
possible observer moments on which a measure is defined (which can be
calculated in principle using the laws of physics), then the paradox never
arises. At any moment you can think of yourself as being randomly drawn from
the set of all possible observer moments. The observer moment who has
survived the suicide experiment time after time after time has a very very
very low measure.


Even if one assumes only a single universe described by the MWI, one has to
consider simulations of other universes. Virtual observers living in such a
simulated universe will perceive their world as real. The measure of such
embedded universes will probably decay exponentialy with complexity....


Saibal

Stathis Papaioannou

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May 26, 2005, 8:17:19 AM5/26/05
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On 25th May 2005 Saibal Mitra wrote:

>One of the arguments in favor of the observer moment picture is that it
>solves Tegmark's quantum suicide paradox. If you start with a set of all
>possible observer moments on which a measure is defined (which can be
>calculated in principle using the laws of physics), then the paradox never
>arises. At any moment you can think of yourself as being randomly drawn
>from
>the set of all possible observer moments. The observer moment who has
>survived the suicide experiment time after time after time has a very very
>very low measure.

I'm not sure what you mean by "the paradox never arises" here. You have said
in the past that although you initially believed in QTI, you later realised
that it could not possibly be true (sorry if I am misquoting you, this is
from memory). Or are you distinguishing between QTI and QS?

--Stathis Papaioannou

_________________________________________________________________
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aet.radal ssg

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May 26, 2005, 12:11:57 PM5/26/05
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For some reason I didn't get the original post about the suicide paradox, so if someone could resend it, sans any "everything" computer lingo, I would appreciate it.

The subject of the thread - "Many Pasts? - Not according to QM"  taken on its face seems false, at least from the standard MWI model. If you have parallel worlds you have parallel pasts. In fact, that's why MWI is supposed to be the solution to time travel paradoxes. Take an arbitrary moment, when a measurement, or any other trigger, causes a decoherence, move forward in time from that moment and look back - you have parallel pasts that begin from the point of decoherence.



----- Original Message -----
From: "Saibal Mitra"
To: everyth...@eskimo.com
Subject: Re: Many Pasts? Not according to QM...
Date: Wed, 25 May 2005 01:24:23 +0200

>
>
>
>
> ----- Oorspronkelijk bericht -----
> Van: "Patrick Leahy"

> Aan:

> Verzonden: Wednesday, May 18, 2005 05:57 PM
> Onderwerp: Many Pasts? Not according to QM...
>
>
> > Of course, many of you (maybe all) may be defining pasts from an
> > information-theoretic point of view, i.e. by identifying all
> > observer-moments in the multiverse which are equivalent as perceived by
> > the observer; in which case the above point is quite irrelevant. (But you
> > still have to distinguish the different branches to find the total measure
> > for each OM).
>
> This is indeed my position. I prefer to define an observer moment as the
> information needed to generate an observer. According to the ''everything''
> hypothesis (I've just seen that you don't subscibe this) an observer moment
> defines its own universe. But this universe is very complex and therefore
> must have a very low measure. It is thus far more likely that the observer
> finds himself embedded in a low complexity universe.
>
>

> One of the arguments in favor of the observer moment picture is that it
> solves Tegmark's quantum suicide paradox. If you start with a set of all
> possible observer moments on which a measure is defined (which can be
> calculated in principle using the laws of physics), then the paradox never
> arises. At any moment you can think of yourself as being randomly drawn from
> the set of all possible observer moments. The observer moment who has
> survived the suicide experiment time after time after time has a very very
> very low measure.
>
>

> Even if one assumes only a single universe described by the MWI, one has to
> consider simulations of other universes. Virtual observers living in such a
> simulated universe will perceive their world as real. The measure of such
> embedded universes will probably decay exponentialy with complexity....
>
>
> Saibal


--

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Saibal Mitra

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May 26, 2005, 1:08:14 PM5/26/05
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The original posting about this dates back from the beginning of this list. I just
invoked this in this thread to argue why one should consider observer moments
(identical ones considered as the same) as fundamental concepts.

The suicide paradox I was referring to is just Tegmark's thought experiment where the
experimenter measures the spin of a particle. If it is down he is instantly killed, he
survives if it is up. Then he argues that according to the MWI the experimenter should
always measure that the spin is up, because that's the only branch in which he
survives.

Saibal

Quoting "aet.radal ssg" <aet.ra...@post.com>:


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Saibal Mitra

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May 26, 2005, 1:10:04 PM5/26/05
to Stathis Papaioannou, smi...@zeelandnet.nl, everyth...@eskimo.com
Quoting Stathis Papaioannou <stathispa...@hotmail.com>:

> On 25th May 2005 Saibal Mitra wrote:
>
> >One of the arguments in favor of the observer moment picture is that it
> >solves Tegmark's quantum suicide paradox. If you start with a set of all
> >possible observer moments on which a measure is defined (which can be
> >calculated in principle using the laws of physics), then the paradox
> never
> >arises. At any moment you can think of yourself as being randomly drawn
> >from
> >the set of all possible observer moments. The observer moment who has
> >survived the suicide experiment time after time after time has a very
> very
> >very low measure.
>
> I'm not sure what you mean by "the paradox never arises" here. You have
> said
> in the past that although you initially believed in QTI, you later realised
>
> that it could not possibly be true (sorry if I am misquoting you, this is
> from memory). Or are you distinguishing between QTI and QS?
>

That's correct. In both QTI and QS one assumes conditional probabilities. You just
throw away the branches in which you don't survive and then you conclude that you
continue to survive into the infinitely far future (or after performing an arbitrary
large number of suicide experiments) with probability 1.

But if you use the a priori probability distribution then you see that you the measure
of versions of you that survive into the far future is almost zero.


Saibal

aet.radal ssg

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May 26, 2005, 7:11:17 PM5/26/05
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Thanks  for the repost. As far as the suicide paradox goes, I'd argue that it's not a paradox. Regardless of how he measures it, if there is a possible alternative, then that alternative exits in a parallel world. The outcome is inconsequential. I see no difference between that and the Schroedinger's Cat example.


----- Original Message -----
From: "Saibal Mitra"
To: "aet.radal ssg"
Subject: Re: Many Pasts? Not according to QM...
Date: Thu, 26 May 2005 19:02:19 +0200

>
> The original posting about this dates back from the beginning of
> this list. I just
> invoked this in this thread to argue why one should consider observer moments
> (identical ones considered as the same) as fundamental concepts.
>
> The suicide paradox I was referring to is just Tegmark's thought
> experiment where the
> experimenter measures the spin of a particle. If it is down he is
> instantly killed, he
> survives if it is up. Then he argues that according to the MWI the
> experimenter should
> always measure that the spin is up, because that's the only branch in which he
> survives.
>
> Saibal
>
> > > > One of the arguments in favor of the observer moment picture
> > is that it > solves Tegmark's quantum suicide paradox. If you
> > start with a set of all > possible observer moments on which a
> > measure is defined (which can be > calculated in principle using
> > the laws of physics), then the paradox
> > never > arises. At any moment you can think of yourself as being
> > randomly drawn
> > from > the set of all possible observer moments. The observer
> > moment who has > survived the suicide experiment time after time
> > after time has a very
> > very > very low measure. > > > Even if one assumes only a single
> > universe described by the MWI, one has
> > to > consider simulations of other universes. Virtual observers
> > living in such
> > a > simulated universe will perceive their world as real. The measure of such
> >
> > > embedded universes will probably decay exponentialy with
> > complexity.... > > > Saibal --
> > ___________________________________________________________
> > Sign-up for Ads Free at Mail.com
> >
> > http://www.mail.com/?sr=signup
> >
> >
> >
> >
>
>
>
>
> --
> _____________________________________________________________________
> Nu 12 maanden gratis Live Eredivisievoetbal bij 20 Mb ADSL voor maar
> EUR 39,95 per maand. Bestel op www.versatel.nl/voetbal

Stathis Papaioannou

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May 26, 2005, 7:52:02 PM5/26/05
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Saibal Mitra wrote:

What does "the measure of versions of you that survive into the far future
is almost zero" actually mean? The measure of this particular version of me
typing this email is practically zero, considering all the other versions of
me and all the other objects in the multiverse. Another way of looking at it
is that I am dead in a lot more places and times than I am alive. And yet
undeniably, here I am! Reality trumps probability every time.

John Collins

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May 27, 2005, 4:08:25 AM5/27/05
to Stathis Papaioannou, everyth...@eskimo.com
If there is a continuum of states in the multiverse (or, rather, if the
states are continuously indexed by the position and momentum of each
particle), then any situation that has a finite or countable description,
(in terms of your perception of that state through observer moments, for
instance) will occur with uncountably large measure, however unlikely the
state. If, however, the underlying basis of states in the multiverse has
itself a discrete structure, this would impose a 'cutoff' on very unlikely
events, so there would be a small fraction of universes wherein my trousers
will fall down at the busstop (why is it always busstops?) but literally
none at all wherein my shirt will fall up into the sky, there being no
configuration of the underlyimg physical variables that would
macroscopically correspond to such an event.
-- Chris Collins

Saibal Mitra

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May 27, 2005, 9:07:19 AM5/27/05
to Stathis Papaioannou, everyth...@eskimo.com
----- Oorspronkelijk bericht -----
Van: "Stathis Papaioannou" <stathispa...@hotmail.com>
Aan: <smi...@zonnet.nl>
CC: <smi...@zeelandnet.nl>; <everyth...@eskimo.com>
Verzonden: Friday, May 27, 2005 01:44 AM
Onderwerp: Re: Many Pasts? Not according to QM...


You have to consider the huge number of alternative states you could be in.

1) Consider an observer moment that has experienced a lot of things. These
experiences are encoded by n bits. Suppose that these experiences were more
or less random. Then we can conclude that there are 2^n OMs that all have a
probability proportional to 2^(-n). The probability that you are one of
these OMs isn't small at all!

2) Considering perforing n suicide experiments, each with 50% survival
probability. The n bits have registered the fact that you have survived the
n suicide experiments. The probability of experiencing that is 2^(-n). The
2^(n) -1 alternate states are all unconscious.


So, even though each of the states in 1 is as likely as the single state in
2, the probability that you'll find yourself alive in 1 is vastly more
likely than in 2. This is actually similar to why you never see a mixture of
two gases spontaneously unmix. Even though all states are equally likely,
there are far fewer unmixed states than mixed ones.

Saibal


Bruno Marchal

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May 27, 2005, 10:41:03 AM5/27/05
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Hi Saibal,

Le 27-mai-05, à 14:29, Saibal Mitra a écrit :


I agree in the case I could imagine all the "observer moments" in some
complete third person way, where the notion of "dying" can be given
some third person sense.
But the compi and the qti, relies, it seems to me, on the fact that we
cannot experience not being there. So that in both case the first
person probabilities are one, from first person points of view. They
are one, *almost* by definition, the very notion of "probabilitiy"
presupposes the ability to test the outcome of a (random) *experiment*
(this is still more plausible for an "observer-moment" first person
*experience*).

Do you see what I try to say?

That's why we need some "no cul-de-sac" hypothesis.

[For those who knows the (Godel Lob Solovay) provability logics (G and
G*) : you can go from a provability logic Bp (= G; with cul-de-sac
accessible from all transitory obsever momente) to a probability logic
(without cul-de-sac) by *imposing* consistency: Bp ==> Bp & -B-p. (-B-p
= 'Consistent p' remember the dual of Bp is -B-p, and with Bp read as
'Provable p', ('Beweisbar p', in German), -B-p is 'Consistent p'. And
if you remind Kripke Semantics, Con p, means there is at least one
observer moment (with p true) accessible from you current observer
moment.
Of course G* proves Bp <-> (Bp & -B-p), But G* proves also -B(Bp <->
(Bp & -B-p)), so that from the machine point point of view, it will
change the provability logic, indeed, it changes it into a probability
logic.]

In my 1988 paper, I argue that the qti is a confirmation of the compi.
(Given that the uda shows comp entails the no cul-de-sac hypothesis).

Or you are (still) with the ASSA ? Or do I miss what you try to explain?

Bruno

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


Bruno Marchal

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May 27, 2005, 11:58:16 AM5/27/05
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Le 27-mai-05, à 16:08, Bruno Marchal a écrit :


> Of course G* proves Bp <-> (Bp & -B-p), But G* proves also -B(Bp <->
> (Bp & -B-p)), so that from the machine point point of view, it will
> change the provability logic, indeed, it changes it into a probability
> logic.]

I' m getting old: please read instead:


> Of course G* proves Bp <-> (Bp & -B-p), But G does not prove Bp <->

> (Bp & -B-p)), so that from the machine point point of view, it will
> change the provability logic, indeed, it changes it into a probability
> logic.]


It is about time you handle those logics if only for correcting my
errors!
I take the opportunity to apology for my bad handling of the "s".

Bruno

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


aet.radal ssg

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May 27, 2005, 2:09:56 PM5/27/05
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Excuse me, has anyone seen a ball around here? It's got an infinity symbol on it. Oh, here it is. OK, just playing through...Fore!


Original Message -----
From: "Saibal Mitra"
To: "Stathis Papaioannou"
Subject: Re: Many Pasts? Not according to QM...
Date: Fri, 27 May 2005 14:29:07 +0200

>
> ----- Oorspronkelijk bericht -----
> Van: "Stathis Papaioannou"
> Aan:
> CC: ;

Stathis Papaioannou

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May 28, 2005, 1:29:34 AM5/28/05
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Saibal Mitra wrote:

>You have to consider the huge number of alternative states you could be in.
>
>1) Consider an observer moment that has experienced a lot of things. These
>experiences are encoded by n bits. Suppose that these experiences were more
>or less random. Then we can conclude that there are 2^n OMs that all have a
>probability proportional to 2^(-n). The probability that you are one of
>these OMs isn't small at all!
>
>2) Considering perforing n suicide experiments, each with 50% survival
>probability. The n bits have registered the fact that you have survived the
>n suicide experiments. The probability of experiencing that is 2^(-n). The
>2^(n) -1 alternate states are all unconscious.
>
>
>So, even though each of the states in 1 is as likely as the single state in
>2, the probability that you'll find yourself alive in 1 is vastly more
>likely than in 2. This is actually similar to why you never see a mixture
>of
>two gases spontaneously unmix. Even though all states are equally likely,
>there are far fewer unmixed states than mixed ones.

I understand your point, but I think you are making an invalid assumption
about the relationship between a random sampling of all the OM's available
to an individual and that individual's experience of living his life.
Suppose a trillion trillion copies of my mind are made today on a computer
and run in lockstep with my biologically implemented mind for the next six
months, at which point the computer is shut down. This means that most of my
measure is now in the latter half of 2005, in the sense that if you pick an
observer moment at random out of all the observer moments which identify
themselves as being me, it is much more likely to be one of the copies on
the computer. But what does this mean for my experience of life? Does it
mean that I am unlikely to experience 2006, being somehow suspended in 2005?

More generally, if a person has N OM's available to him at time t1 and kN at
time t2, does this mean he is k times as likely to find himself experiencing
t2 as t1? I suggest that this is not the right way to look at it. A person
only experiences one OM at a time, so if he has "passed through" t1 and t2
it will appear to him that he has spent just as much time in either interval
(assuming t1 and t2 are the same length). The only significance of the fact
that there are "more" OM's at t2 is that the person can expect a greater
variety of possible experiences at t2 if the OM's are all distinct.

--Stathis Papaioannou

_________________________________________________________________
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Hal Finney

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May 28, 2005, 2:18:40 AM5/28/05
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Stathis Papaioannou writes:
> More generally, if a person has N OM's available to him at time t1 and kN at
> time t2, does this mean he is k times as likely to find himself experiencing
> t2 as t1? I suggest that this is not the right way to look at it. A person
> only experiences one OM at a time, so if he has "passed through" t1 and t2
> it will appear to him that he has spent just as much time in either interval
> (assuming t1 and t2 are the same length). The only significance of the fact
> that there are "more" OM's at t2 is that the person can expect a greater
> variety of possible experiences at t2 if the OM's are all distinct.

It's a good puzzle. Some time back I expressed it as follows: suppose
the measure of the even days of my life were arranged to be twice as
good as the measure of the odd days. How would I notice this? Would I
somehow be more likely to experience an even day? Should I arrange
to have good things happen on even days and bad things on odd days?
I don't see how I would notice any difference.

Now, I lean more to a favorable answer to these questions. In fact I
would say, yes, I should arrange to have good things happen on even days.
Even though the difference is not directly perceptible, I believe I
would be making the universe a better place.

Here are a chain of examples. I won't try to offer much justification
at each step, I am just sketching an argument.

First, consider 10 people. We can either give 9 of them a good experience
and 1 of them a bad one, or 9 of them bad and 1 of them good. It is
clear that it is better to give the 9 good and 1 bad.

Now, consider 2 people. We are going to give the first a good experience
and the second a bad one. But we can make 9 copies of the first, or
9 copies of the second, as we do it. I claim it is better to make 9
copies of the first, the one who is having a good experience.

Now, consider a person who goes through life but who has a problem with
his short term memory that makes him forget what happens every day.
(Fictional examples can be seen in the movies Memento and Fifty First
Dates, although I don't know how realistic they are. Keep in mind this
is just a thought experiment and not dependent on any actual details of
human pathology.) We can either give him 9 days of good experiences
and 1 bad, or vice versa. I claim it is better to make the 9 days be
good experiences and 1 day bad, rather than the other way around.

And finally consider an ordinary person who remembers things from one
day to the next. On day 1 something good happens and on day 2 something
bad happens. We can either make him have 9 times the measure on day 1
or on day 2. I claim that it is better to give him 9 times the measure
on day 1, when the good thing happens.

Now, you may be saying, where is the argument? These are just examples
with unsupported claims. The point is to show that in all these examples
the people are unaware of the changes in measure and numbers of good
and bad experiences. But that doesn't change the fact that it is still
better to cause more good experiences in the world than bad.

Would we say that it is OK to mistreat a person with lack of short
term memory just because they won't remember it? I don't think so.
It still causes genuine pain and suffering. Giving them good experiences
causes joy. The 50 First Dates movie expresses this in a poignant and
moving matter. People are willing to sacrifice to bring happiness to
someone they love who suffers such a condition. I thought this was
an excellent movie BTW, although you have to overlook some extremely
juvenile humor. Memento was also interesting but much darker in tone.

It is the same with all the examples. Causing more experiences of
joy is better than causing more experiences of sadness. Even with
the one person who lives from day to day, it still applies. He is not
subjectively aware of his measure changing, but if he or anyone else has
objective awareness of the circumstance, the same logic that applies in
the other examples works here as well. Give more happiness to the days
with greater measure. That makes the world a better place.

Now for an interesting twist. Our measure decreases steadily in life.
Every day we have a certain probability of dying, and our measure
decreases by that fraction. The reasoning in the examples above would
imply that it is better to have happiness when our measure is high, which
is when we are young. Unhappiness in old age has less impact. So if
you are putting off some happiness, do it today, don't procrastinate.

(Of course, you get much the same result in a non-multiverse model,
where putting off a reward makes you risk dying before you get to
experience it.)

Hal Finney

Quentin Anciaux

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May 28, 2005, 3:08:20 AM5/28/05
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Le Samedi 28 Mai 2005 07:21, "Hal Finney" a écrit :
> It is the same with all the examples. Causing more experiences of
> joy is better than causing more experiences of sadness. Even with
> the one person who lives from day to day, it still applies. He is not
> subjectively aware of his measure changing, but if he or anyone else has
> objective awareness of the circumstance, the same logic that applies in
> the other examples works here as well. Give more happiness to the days
> with greater measure. That makes the world a better place.

Good faith, but I see no point, no justification.

> Now for an interesting twist. Our measure decreases steadily in life.
> Every day we have a certain probability of dying, and our measure
> decreases by that fraction.

I don't understand how the measure can decrease if there exists an infinity of
computations passing through a particular states (assuming you talk about
comp.), meaning any particular states of "my" life is
emulated/simulated/emergent creation of an infinity of computations. The
problems when talking about this, an OM, is the "I", what is it in this
configuration ? Does the feeling of being is just an illusion, despite it be
a strong feeling ?

> The reasoning in the examples above would
> imply that it is better to have happiness when our measure is high, which
> is when we are young. Unhappiness in old age has less impact. So if
> you are putting off some happiness, do it today, don't procrastinate.
> (Of course, you get much the same result in a non-multiverse model,
> where putting off a reward makes you risk dying before you get to
> experience it.)
>
> Hal Finney

Like I said, it's a beautiful idea, but it is just faith.

Quentin Anciaux

Stathis Papaioannou

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May 28, 2005, 8:00:16 AM5/28/05
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Hal Finney writes:

The conclusion drawn from the examples you have given is very reasonable,
taking the point of view of a third person observer. There is nothing wrong
with that, but what I was asking is, from a selfish first person point of
view, can I expect to live forever, as the QTI seems to imply? One objection
to the QTI is that most of my measure is concentrated in younger versions of
me, so that it is extremely unlikely that a randomly chosen OM from my life
will be, say, a million years old. But this objection is answered by your
conclusion (and mine) that if your measure on even days of your life were
somehow made double your measure on odd days, you would not notice any
difference. As long as even one version of me survives in the multiverse,
however low the measure, I am guaranteed to remain alive.

--Stathis Papaioannou

_________________________________________________________________
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Saibal Mitra

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May 28, 2005, 8:35:53 AM5/28/05
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Hi Bruno

----- Oorspronkelijk bericht -----
Van: "Bruno Marchal" <mar...@ulb.ac.be>
Aan: "Saibal Mitra" <smi...@zeelandnet.nl>
CC: "Stathis Papaioannou" <stathispa...@hotmail.com>;
<everyth...@eskimo.com>
Verzonden: Friday, May 27, 2005 04:08 PM


I'm actually still with the ASSA. I agree that if there is no cul-de-sac,
you can always redefine an observer moment by including the information that
he has survived a suicide experiment. But I would consider that observer
moment to have a lower measure than the 'previous' one. Also, if you take
the first person relative measure serious, then you have to deal with
transitions between different persons. Time evolution in both classical and
quantum mechanics of an isolated system will yield any state if you wait
long enough. So, you will evolve into me (and everything else). Now you can
cut away these states just like the unconscious states, but since the total
number of OMs that you can consider to be 'you' is finite you then end up
with an absolute measure over your 'reference class'.


Saibal

Saibal Mitra

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May 28, 2005, 9:24:51 AM5/28/05
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----- Oorspronkelijk bericht -----
Van: "Stathis Papaioannou" <stathispa...@hotmail.com>
Aan: <smi...@zeelandnet.nl>
CC: <everyth...@eskimo.com>
Verzonden: Saturday, May 28, 2005 07:26 AM

Onderwerp: Re: Many Pasts? Not according to QM...

I would say so. You would find yoursef to be suspended in 2005, just like
you are now suspended between 1900 and 2100. But this would require the
simulations of your mind in 2005 to dominate over all other versions of you.
Now unless experiencing 2006 would require a miracle this can't be the case.
The reason is that all possible versions of you 'already' exist in the
multiverse. Your measure in 2005 is what it is. This includes the effects of
others simulating your mind experiencing 2005 (the simulation can be done at
any time, of course).

So, you can say that your measure for experiencing time t is:

m(t) = m_{biol}(t) + m_{sim}(t)


m_{biol} being the 'biological' contribution of your measure and m_{sim} the
digital contribution. Both terms are fixed by the laws of physics. If indeed
m_{sim}(2005) is trillions of times larger than m_{biol}(2005) and zero at
other times, you would be suspended in 2005. But this cannot be the case
unless there is some reason why m_{sim}(t) is so strongly peaked around
2005. If there are branches in which someone is simulating you in 2005 for
no good reason, then that decision is taken at random. That means that in
some other branch you are simulated in some other time. So, the measure
isn't strongly peaked around 2005 at all!


>
> More generally, if a person has N OM's available to him at time t1 and kN
at
> time t2, does this mean he is k times as likely to find himself
experiencing
> t2 as t1? I suggest that this is not the right way to look at it. A person
> only experiences one OM at a time, so if he has "passed through" t1 and t2
> it will appear to him that he has spent just as much time in either
interval
> (assuming t1 and t2 are the same length). The only significance of the
fact
> that there are "more" OM's at t2 is that the person can expect a greater
> variety of possible experiences at t2 if the OM's are all distinct.


The same is true here. It must follow from the laws of physics (which
include the effects of simmulations) that there are indeed many more copies
of you at t2.


Saibal


Bruno Marchal

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May 28, 2005, 11:46:02 AM5/28/05
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Le 28-mai-05, à 14:32, Saibal Mitra a écrit :

>
> I'm actually still with the ASSA. I agree that if there is no
> cul-de-sac,
> you can always redefine an observer moment by including the
> information that
> he has survived a suicide experiment. But I would consider that
> observer
> moment to have a lower measure than the 'previous' one.

OK, thanks. Now if I am correct you should not assume comp.


> Also, if you take
> the first person relative measure serious, then you have to deal with
> transitions between different persons. Time evolution in both
> classical and
> quantum mechanics of an isolated system will yield any state if you
> wait
> long enough. So, you will evolve into me (and everything else).

Perhaps.

> Now you can
> cut away these states just like the unconscious states, but since the
> total
> number of OMs that you can consider to be 'you' is finite you then end
> up
> with an absolute measure over your 'reference class'.


Right. But with comp the relative measure from one OM is based on all
comp histories going through that states. We should not measure the OM
by its finite description, but from relative consistent extension point
of view. Most cannot be distinguished from the OM, but still their
existence and the measure can be inferred indirectly like in Everett
(or directly like with the interview of the Lobian Machine).

Bruno

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


Stathis Papaioannou

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May 29, 2005, 7:30:04 AM5/29/05
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Saibal Mitra wrote:

[quoting Stathis]

In dealing with this type of problem you have to consider not only the
physics, which I'm sure you understand much better than I do, but also the
psychology of how the first person experience of being a unique individual
persisting through time is constructed from observer moment building blocks.
This is not as obvious as may first appear; specifically, it does not follow
in general that more copies/ greater measure at time t = more likely to
experience time t. The important thing to keep in mind is that each
individual experiences only one OM at a time. If I consider the future, then
there is a potential that I could "become" any of the many OM's who consider
me to be in their past. However, when I arrive at the future, and also when
I remember the past, I consider myself to be unique. All the other OM's
which from a third person perspective are other versions of "me" (and this
third person perspective includes me looking at my potential futures) from
my perspective are completely separate people. So if I am told that tomorrow
I will be copied ten times and one of these copies will be tortured, I am
worried, because that means there is a 1/10 chance I will be tortured. But
when tomorrow comes and I am not the torture victim, I am relieved, because
it is someone else who is suffering, and I can feel sorry for him in the way
I feel sorry for suffering strangers.

What this means is that if you trace an individual's history from his birth
to his ultimate demise (which may never come, if QTI is correct), at each
time point he is associated with only *one* OM. Two or more individuals may
share two or more OM's at some point in their life, for example when a
duplication occurs, but from the point of view of each of them, they still
only experience one OM at a time for their entire life history. Two OM's may
also "combine" in one of two ways: either a third OM exists with the content
of the other two, or they do not really combine but a later OM has the
memory of having been both in the past. The one OM per time point for each
individual rule is maintained.

The conclusion from the above is that the absolute measure of an individual
at any time point, from that individual's point of view, is unity. When
looking into the future, the other copies in the multiverse do matter, but
in this case it is the relative measure of different outcomes rather than
the absolute measure which is important. Once the future becomes present,
the other copies from the first person perspective are just other people.

Lee Corbin

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Jun 2, 2005, 2:54:35 AM6/2/05
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Stathis writes

> I understand [Saibal's] point, but I think you are making an invalid assumption

> about the relationship between a random sampling of all the OM's available
> to an individual and that individual's experience of living his life.
> Suppose a trillion trillion copies of my mind are made today on a computer
> and run in lockstep with my biologically implemented mind for the next six
> months, at which point the computer is shut down.

Yes, and I note that these are *precisely* identical instantiations.

> This means that most of my
> measure is now in the latter half of 2005, in the sense that if you pick an
> observer moment at random out of all the observer moments which identify
> themselves as being me, it is much more likely to be one of the copies on
> the computer.

What? And I thought that I had understood how the term "Observer
Moment" is used on this list! :-(

Is the following true, or isn't it: identical OMs are identified.
That is, N identical instances (say, running on N identical mainframes)
are thought of as *one* observer moment, because they are (1st person)
indistinguishable. At least that is how *I* have been using the term.
(They're also 3rd person indistinguishable, of course.)

Bruno wrote, incidentally, "With comp the relative measure from one OM
is based on all comp histories going through [those] states. We should
not measure the OM by its finite description...", and so it's possible
that he is agreeing with my usage of the term "Observer Moment"."

Thanks for any clarification.

> But what does this mean for my experience of life? Does it
> mean that I am unlikely to experience 2006, being somehow
> suspended in 2005?

I would say "no". I would say that *you* must experience 2006
in your experiment, and in fact, in any universe where you
live through 2006.

If we say that there are 2006 AD versions of Stathis running
anywhere in the multiverse, then it is by definition true that
you get runtime in 2006 (or that you experience 2006). What a
number of us have tried to do, perhaps mainly so that our ideas
conform with our daily values of trying to stay alive, is to
regard the *benefit* one receives from a certain amount of
runtime as the measure of the OM.

Hal has very satisfactorily described the idea that you get superior
benefit if your pleasant, even-numbered-days are given twice the
measure of your odd, unpleasant days.

> More generally, if a person has N OM's available to him at time t1 and kN at
> time t2, does this mean he is k times as likely to find himself experiencing
> t2 as t1?

To me "to find oneself at X,t" in spacetime means to make an
observation that one is at position X at time t, or perhaps
better, that one is alive at X,t, a very 1st person description.
But then, that would tend to distinguish the experience at t2
from the experience at t1, and that is contrary to your hypothesis.

By the definition I thought was in vogue here, "from inside"
there is just one OM, even though it's manifested at a number
of spacetime locations (the entity doesn't know the difference).

On a 3rd person objective bird's-eye view the greater number of
instances do have, of course, a greater measure than does a
single instance. So how does this translate to 1st person?
I'd suggest that one's 1st person experience---though not
memorably different---is "richer" and "fuller", and of more
benefit to one! :-) Admittedly, this sounds like nonsense
if one believes that one's memories capture all of one's
experience.

> I suggest that this is not the right way to look at it. A person
> only experiences one OM at a time, so if he has "passed through"
> t1 and t2 it will appear to him that he has spent just as much

> time in either interval...

Yes, but appearances can be deceiving! And it won't be the first
time that a patient is incorrect about which of two time intervals
actually provided him the greater benefit.

> The only significance of the fact that there are "more" OM's at

> t2 [and I take it to mean that, using the terms as I do, the
> OM at t2 has greater measure than the OM at t1] is that the


> person can expect a greater variety of possible experiences at
> t2 if the OM's are all distinct.

Again, to me, if the experiences are distinct, then it's not the
same OM.

Lee

Lee Corbin

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Jun 2, 2005, 9:28:48 AM6/2/05
to EverythingList
I continue to describe a different way of talking than that
used by Stathis, who writes

> [Saibal writes]


>
> > The same is true here. It must follow from the laws of physics (which

> > include the effects of simulations) that there are indeed many more copies
> > of you at t2.

Yes, we can say that there are more *copies*, i.e. more instantiations,
and that these provide altogether more runtime at t2 (whatever X is).

> In dealing with this type of problem you have to consider not only the
> physics, which I'm sure you understand much better than I do, but also the
> psychology of how the first person experience of being a unique individual
> persisting through time is constructed from observer moment building blocks.

Yes, nature would naturally construct creatures that looked at it
this way. It would not do, for example, for a lion to have other
than a single memory stream that described his current environment,
and, to the degree it is useful, how he got there.

> This is not as obvious as may first appear; specifically, it does not follow
> in general that more copies/ greater measure at time t = more likely to
> experience time t. The important thing to keep in mind is that each
> individual experiences only one OM at a time.

As I say it, one is *certain* to experience time t under your
hypothesis. I consider whether one experiences time t to be
an objective question: an examination of, say, the solar system
during a certain interval (Jan 2006 to Dec 2006) reveals that
either Stathis got runtime there or he didn't.

But "only one OM at a time"? No, not if we are speaking of time
in the objective sense: again, a piecemeal examination of a certain
region of space could easily show that Stathis is running at two
separate locations even at the same time t1. In fact, one possibility
is that Stathis(X1, t1) has the same OM as Stathis(X2, t1).

> If I consider the future, then there is a potential that I
> could "become" any of the many OM's who consider me to be
> in their past.

I suggest that it is better to drop the language of probability
here. It is *certain* that you will become all the Stathis's
of 2006. You will be some of them in greater measure than others.

> However, when I arrive at the future, and also when I remember
> the past, I consider myself to be unique. All the other OM's
> which from a third person perspective are other versions of
> "me" (and this third person perspective includes me looking
> at my potential futures) from my perspective are completely
> separate people.

I would say that they are separate instances, but not separate
people. (A corollary from the usual belief that we are the same
person from day to day even though our memories, obviously, are
not identical.) You are the same person that you were yesterday,
and tomorrow you will be the same person you are today, unless
we do great violence to what we mean by "person". Derek Parfit
in "Reasons and Persons" (1986) analyses this in great detail,
along with Mike Perry in "Forever For All".

> So if I am told that tomorrow I will be copied ten times and
> one of these copies will be tortured, I am worried, because
> that means there is a 1/10 chance I will be tortured.

Good example, but I would say that you will be tortured with
100% probability at some places, and tortured with 0% probability
at nine others. The characterization of a piece of matter "Stathis
is undergoing torture" is looked upon from the 3rd person as an
entirely physically characterized objective process.

> But when tomorrow comes and I am not the torture victim, I am
> relieved, because it is someone else who is suffering, and I can
> feel sorry for him in the way I feel sorry for suffering strangers.

I suggest that this is not the correct, selfish way that you should
look at it. It's just the same as in MWI when there "really is" a
version of you who saw the other outcome. He's you. I have a so-called
proof of this proposition at http://www.leecorbin.com/dupproof.html

> What this means is that if you trace an individual's history from his birth
> to his ultimate demise (which may never come, if QTI is correct), at each
> time point he is associated with only *one* OM.

Perhaps my insistence wherever possible of describing what is
happening in our universe from the 3rd person is responsible
for our different ways of talking.

> Two or more individuals may share two or more OM's at some point
> in their life, for example when a duplication occurs, but from
> the point of view of each of them, they still only experience one
> OM at a time for their entire life history. Two OM's may
> also "combine" in one of two ways: either a third OM exists with the content
> of the other two, or they do not really combine but a later OM has the
> memory of having been both in the past. The one OM per time point for each
> individual rule is maintained.
>
> The conclusion from the above is that the absolute measure of an individual
> at any time point, from that individual's point of view, is unity. When
> looking into the future, the other copies in the multiverse do matter, but
> in this case it is the relative measure of different outcomes rather than
> the absolute measure which is important. Once the future becomes present,
> the other copies from the first person perspective are just other people.

Well, we aren't yet used to having more than one of us around
at any given time. Perhaps our gut feelings on this issue will
change when the technology allows duplicates. I, for example,
would never dream of regarding my duplicate as another person.
He's me, just running at a different location. (Just as, for
example, my future and past selves are also me, just running
at different times.)

Lee

Bruno Marchal

unread,
Jun 2, 2005, 9:59:31 AM6/2/05
to lco...@tsoft.com, EverythingList

Le 02-juin-05, à 08:48, Lee Corbin a écrit :

> What? And I thought that I had understood how the term "Observer
> Moment" is used on this list! :-(

You are optimist :)

According to Nick Bostrom who introduced the term, "observer-moments
are pieces of subjective time"
(http://www.escribe.com/science/theory/m1220.html).

I think that some people here associate them to computational states. I
do that but it is not a 1-1 correspondence. You can associate an
"observer-moment" to some (sufficiently rich) computational state, but
to each "observer-moment" you can only associate an infinity of
computational states. All regularly accessed by the Universal
Dovetailer through many computations/histories. Now those computational
state are relative state. They make sense only with respect to a most
probable history/universal-machine/maximal consistent extension ... I
don't think the ASSA people would agree, and I would appreciate they
make more precise their notion of "observer moment".

> Bruno wrote, incidentally, "With comp the relative measure from one OM
> is based on all comp histories going through [those] states. We should
> not measure the OM by its finite description...", and so it's possible
> that he is agreeing with my usage of the term "Observer Moment"."


I hope so ;), we will see.


Bruno


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

Bruno Marchal

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Jun 2, 2005, 10:28:44 AM6/2/05
to lco...@tsoft.com, EverythingList

Le 02-juin-05, à 15:23, Lee Corbin a écrit :

>
>> Stathis: So if I am told that tomorrow I will be copied ten times and


>> one of these copies will be tortured, I am worried, because
>> that means there is a 1/10 chance I will be tortured.
>
> Good example, but I would say that you will be tortured with
> 100% probability at some places, and tortured with 0% probability
> at nine others. The characterization of a piece of matter "Stathis
> is undergoing torture" is looked upon from the 3rd person as an
> entirely physically characterized objective process.

But here I agree with Stathis. What you say can be said with the throw
of a dice. There *will be* a 100% probability that I will experience
the result n (with n = 1, 2, ...6). And if I make the dice rolling a
long time, by adding the Heisenberg uncertainties there will be (with
the MWI) a 100% probability for each outcome. But before the experience
I am in a maximal state of ignorance, and that gives usually P = 1/6.

>
>> Stathis: But when tomorrow comes and I am not the torture victim, I am


>> relieved, because it is someone else who is suffering, and I can
>> feel sorry for him in the way I feel sorry for suffering strangers.
>
> I suggest that this is not the correct, selfish way that you should
> look at it. It's just the same as in MWI when there "really is" a
> version of you who saw the other outcome. He's you. I have a so-called
> proof of this proposition at http://www.leecorbin.com/dupproof.html

I agree "it is you", but I follow Stathis' intuition that before the
"splitting" the proba is 1/10 of being "that "you"".
If not with comp you must accept that Bruno Marchal *is* Lee Corbin.
I think we did arrive at that conclusion before, isn'it?

>
>> Stathis: What this means is that if you trace an individual's history

>> from his birth
>> to his ultimate demise (which may never come, if QTI is correct), at
>> each
>> time point he is associated with only *one* OM.
>
> Perhaps my insistence wherever possible of describing what is
> happening in our universe from the 3rd person is responsible
> for our different ways of talking.

That's an excellent diagnostic. That will help you to understand how I
derive the very existence of the "physical laws" or "observable theory"
from a ineluctable gap between 1 and 3 person.

>>
>> The conclusion from the above is that the absolute measure of an
>> individual
>> at any time point, from that individual's point of view, is unity.
>> When
>> looking into the future, the other copies in the multiverse do
>> matter, but
>> in this case it is the relative measure of different outcomes rather
>> than
>> the absolute measure which is important. Once the future becomes
>> present,
>> the other copies from the first person perspective are just other
>> people.
>
> Well, we aren't yet used to having more than one of us around
> at any given time. Perhaps our gut feelings on this issue will
> change when the technology allows duplicates. I, for example,
> would never dream of regarding my duplicate as another person.
> He's me, just running at a different location. (Just as, for
> example, my future and past selves are also me, just running
> at different times.)


Suppose immortality (for the sake of the argument). Lee1 and Lee2 can
become as different as Bruno and Lee now.
I think you should consider me as a "you" right now. We were the same
amoeba you know, a long time ago.


Bruno (I mean Lee ;)


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


Stathis Papaioannou

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Jun 2, 2005, 11:10:40 AM6/2/05
to lco...@tsoft.com, everyth...@eskimo.com
Lee Corbin writes:

You're right, I've been sloppy. If the OM's are the same, then from the
first person perspective there is only one OM. One OM can have multiple
instantiations, but by definition there is no way for the OM to know this,
otherwise they would be distinct OM's. There is no way to distinguish
between them from a third person perspective either, although the fact that
there are multiple instantiations may be obvious. This actually suggests a
more elegant way to make my point, which is that the absolute measure makes
no possible difference to the OM.

>Bruno wrote, incidentally, "With comp the relative measure from one OM
>is based on all comp histories going through [those] states. We should
>not measure the OM by its finite description...", and so it's possible
>that he is agreeing with my usage of the term "Observer Moment"."
>
>Thanks for any clarification.
>
> > But what does this mean for my experience of life? Does it
> > mean that I am unlikely to experience 2006, being somehow
> > suspended in 2005?
>
>I would say "no". I would say that *you* must experience 2006
>in your experiment, and in fact, in any universe where you
>live through 2006.
>
>If we say that there are 2006 AD versions of Stathis running
>anywhere in the multiverse, then it is by definition true that
>you get runtime in 2006 (or that you experience 2006). What a
>number of us have tried to do, perhaps mainly so that our ideas
>conform with our daily values of trying to stay alive, is to
>regard the *benefit* one receives from a certain amount of
>runtime as the measure of the OM.
>
>Hal has very satisfactorily described the idea that you get superior
>benefit if your pleasant, even-numbered-days are given twice the
>measure of your odd, unpleasant days.

I don't see how this follows. I can't even imagine what it might mean to get
"higher benefit" from higher measure days. What I assumed Hal meant was that
on even days his total measure was higher, so that double the usual number
of versions of Hal were generated in other branches of the multiverse, who
would go on to have separate and distinct lives. Aiming for more good
experiences on even days would then be an altruistic thing for Hal to do,
since it would result in greater happiness in the multiverse as a whole. If,
instead, it was more like my example, where a copy of Hal's mind is run on a
computer in lockstep with his biological mind on even days, and the computer
switched off on odd days, then what possible difference could it make to Hal
or anyone else, given what we have just said about the definition of an OM?

> > More generally, if a person has N OM's available to him at time t1 and
>kN at
> > time t2, does this mean he is k times as likely to find himself
>experiencing
> > t2 as t1?
>
>To me "to find oneself at X,t" in spacetime means to make an
>observation that one is at position X at time t, or perhaps
>better, that one is alive at X,t, a very 1st person description.
>But then, that would tend to distinguish the experience at t2
>from the experience at t1, and that is contrary to your hypothesis.

I did mean that t1 and t2 are distinct. This is basically the same question
as Hal's about different measure on different days. I should have said "N
instantiations of an OM". Sorry, I've been sloppy again!

>By the definition I thought was in vogue here, "from inside"
>there is just one OM, even though it's manifested at a number
>of spacetime locations (the entity doesn't know the difference).
>
>On a 3rd person objective bird's-eye view the greater number of
>instances do have, of course, a greater measure than does a
>single instance. So how does this translate to 1st person?
>I'd suggest that one's 1st person experience---though not
>memorably different---is "richer" and "fuller", and of more
>benefit to one! :-) Admittedly, this sounds like nonsense
>if one believes that one's memories capture all of one's
>experience.

No, I can't agree with this at all. In fact, it's the first thing you've
said since joining the list that isn't impeccably rational, IMHO. (Sorry,
hope that comes across as a compliment :-)

> > I suggest that this is not the right way to look at it. A person
> > only experiences one OM at a time, so if he has "passed through"
> > t1 and t2 it will appear to him that he has spent just as much
> > time in either interval...
>
>Yes, but appearances can be deceiving! And it won't be the first
>time that a patient is incorrect about which of two time intervals
>actually provided him the greater benefit.

Are you suggesting that, in general, the moment with greater measure will
seem the same, but it won't actually be the same? If so, is there some test
that could be done to prove objectively that there is a difference?

> > The only significance of the fact that there are "more" OM's at
> > t2 [and I take it to mean that, using the terms as I do, the
> > OM at t2 has greater measure than the OM at t1] is that the
> > person can expect a greater variety of possible experiences at
> > t2 if the OM's are all distinct.
>
>Again, to me, if the experiences are distinct, then it's not the
>same OM.

Again, you're right. I was referring to the distinct OM's associated with an
individual across the multiverse at a certain time point, captured by the
term "total measure". It is necessarily fuzzy, because we can't really
define what OM is and isn't associated with an individual. As a person gets
older, and it becomes increasingly likely that he will die from age related
disease, I imagine that the effect of this is that more and more branches of
the multiverse are "pruned", decreasing his total measure and limiting his
possible futures, even though he never actually dies.

Hal Finney

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Jun 2, 2005, 1:15:21 PM6/2/05
to everyth...@eskimo.com
Stathis Papaioannou writes:
> I don't see how this follows. I can't even imagine what it might mean to get
> "higher benefit" from higher measure days. What I assumed Hal meant was that
> on even days his total measure was higher, so that double the usual number
> of versions of Hal were generated in other branches of the multiverse, who
> would go on to have separate and distinct lives. Aiming for more good
> experiences on even days would then be an altruistic thing for Hal to do,
> since it would result in greater happiness in the multiverse as a whole. If,
> instead, it was more like my example, where a copy of Hal's mind is run on a
> computer in lockstep with his biological mind on even days, and the computer
> switched off on odd days, then what possible difference could it make to Hal
> or anyone else, given what we have just said about the definition of an OM?

To clarify, I did indeed mean the equivalent of this latter case,
where by some means on even numbered days I had more measure, and
on odd numbered days my measure was then reduced to a lower amount.
This might be done as you say by running a computer in lockstep with my
mind on even days and shutting it off on odd days, if you accept that
doing so will increase the measure of the even days.

My message is at http://www.escribe.com/science/theory/m6592.html .

The argument is fundamentally that creating a bunch of good experiences is
better than creating a bunch of bad ones. Shutting the computer down doesn't
matter. That just means that the good experiences won't be remembered. But
they were still real, they were still experienced.

After all, many people believe our own lives are finite in extent and
that after we die we will have no more memories of our lives. But they
(mostly) don't conclude from that that it is irrelevant whether people
suffer or experience pleasure. Even finite lives deserve to be as happy
as possible. This is true whether they last for one day or 100 years.

And worse, almost all of the moments of our lives are forgotten within
days if not minutes. Most moments make essentially no impact on our
memories. We can't remember what it felt like to brush our teeth on
February 9. Yet, even knowing this, we still try to make our lives as
pleasant and comfortable as we can. Even though we would have known
(had we thought about it) as we were brushing our teeth that day, that we
would not remember that moment, that it would soon be forgotten as surely
as if we had never lived it, we would still try to make the experience
as pleasant and non-painful as possible.

All these examples are meant to show that we act as though we care about
giving good experiences even though we know they will be forgotten and
not have lasting impact. If we extend that principle more generally,
I think it follows that we should try to have good experiences on days
when we have high measure.

Hal Finney
(Note that there are two Hals on this list)

Quentin Anciaux

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Jun 2, 2005, 1:30:14 PM6/2/05
to everyth...@eskimo.com
Hi Hal,

I don't follow you very well, and I tried to ask you two times a question
which does not seems to be of interrest to respond (or maybe my english is so
bad, that it doesn't mean anything ?). But I'll try once more.

What I understand from that is as if you could influence probabilty, as if
knowing something or acting in some way will change your "future" Hal by
having him "good moments"... But if at every choice, every results exists
(whatever the measures of each one).. Some Hal are always garanteed to have a
"bad' experience and some other garanteed to have a "good" experience,
whatever you knew before the choice, whatever the measure. So my question is
how could you think acting "good" change anything in this matter ? And also
what is "good" and what is not "good" and how you classify these ?

Thank you
Quentin Anciaux

rmiller

unread,
Jun 2, 2005, 1:52:56 PM6/2/05
to Hal Finney, everyth...@eskimo.com
At 11:20 AM 6/2/2005, Hal Finney wrote:
>(snip)

>
>All these examples are meant to show that we act as though we care about
>giving good experiences even though we know they will be forgotten and
>not have lasting impact. If we extend that principle more generally,
>I think it follows that we should try to have good experiences on days
>when we have high measure.
>
>Hal Finney

I've always thought that QM offered great tools for social scientists, and
here's another example. Is it worthwhile to consider a life as the sum of
experiences along a given track of the world line, or can we borrow from
Feynman and view life as a "sum over histories?" If so, it might explain
false memories, love at first sight and coincidence.

Richard Miller

Hal Finney

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Jun 2, 2005, 4:01:54 PM6/2/05
to everyth...@eskimo.com
Quentin Anciaux writes:
> What I understand from that is as if you could influence probabilty, as if
> knowing something or acting in some way will change your "future" Hal by
> having him "good moments"... But if at every choice, every results exists
> (whatever the measures of each one).. Some Hal are always garanteed to have a
> "bad' experience and some other garanteed to have a "good" experience,
> whatever you knew before the choice, whatever the measure. So my question is
> how could you think acting "good" change anything in this matter ? And also
> what is "good" and what is not "good" and how you classify these ?

I'm not sure I understand exactly what you are getting at, but here are
a couple of ideas that may help improve our communication.

One issue with a multiverse concept is that since "everything will happen"
then it seems that we do not really make choices. We don't have free
will. When we choose between A and B, even if we take a long time to make
the choice, there will still be universes where we choose A and universes
where we choose B. So it seems that we did not make a choice after all.

To this I make two responses. The first is that even though
everything will happen, not everything happens with equal measure,
or equal probability. For a multiverse model to make sense we must
(in my opinion) include the notion that some universes are more likely
and have greater measure than others. Otherwise we cannot explain why
natural laws continue to work and our universe does not degenerate all
around us into chaos.

Given that different universes in the multiverse have different measure,
this puts a different light on choice. Although it may be true that
we will make both choices in some universes, by our process of careful
thought and consideration, we do make a difference. We change the
measure of the possible universes.

If we just flip a coin to make the choice, then both outcomes will
happen with equal probability and both universes will have equal measure.
But if we think about it carefully and then decide to do A, that gives
more measure to the universe where A happens. If we consider all versions
of ourselves, most of them will make that same decision, and most measure
will go into the universes where that is the choice.

So the nature of choice in a multiverse is that it is a matter of changing
the measure of the universes where the consequences happen.

The second point related to this is that some people may object that even
the appearance of making a choice is an illusion, because our thoughts
are determined by events and causes outside of ourselves. This is an old
argument and is not specific to multiverse models. Suffice it to say
that there is an extensive philosophical literature, and in particular
the doctrine of "compatibilism" describes how we can think of making
meaningful choices even though we may live in a deterministic universe.

Hopefully these ideas will help you see how it does make sense to make
choices and take actions even in a multiverse. This is not specific
to my thought experiment, it relates to everyday, ordinary action.
Every breath we take is a choice to live. Even in a multiverse it makes
sense to think of our actions in this way.

As far as your final question about what I meant by "good" in my
experiment, it's not very important what the details are. I just
want to distinguish relatively pleasant events from those which are
not so pleasant. The main point was to shed light on the question of
how we can reconcile two models of experience: a linear model where
we pass through life in a straight line from birth to death; or a
random-sampling model where every moment of every person's life exists
somewhat independently, and we could imagine a probability distribution
over those observer-moments which determines how likely they are to
be experienced. My thought experiment was an attempt to describe a
situation where the two views would seem to give different answers
about what we would do, to help us understand how they differ.

Hal

scerir

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Jun 2, 2005, 5:36:21 PM6/2/05
to everyth...@eskimo.com
> Is it worthwhile to consider a life as the sum of
> experiences along a given track of the world line,
> or can we borrow from Feynman and view life as
> a "sum over histories?"
> Richard Miller

Borges wrote something about it, a sort of
MWI, or Many Times Interpretation, or
many zigzagging paths, or just one path
but circling around in a space-time diagram
:-)

"... a picture, incomplete yet not false,
of the universe as Ts'ui Pen conceived it to be.
Differing from Newton and Schopenhauer, ...
[he] did not think of time as absolute and uniform.
He believed in an infinite series of times,
in a dizzily growing, ever spreading network
of diverging, converging and parallel times.
This web of time -- the strands of which approach
one another, bifurcate, intersect or ignore
each other through the centuries -- embraces
every possibility. We do not exist in most of them.
In some you exist and not I, while in others I do,
and you do not, and in yet others both of us exist.
In this one, in which chance has favored me,
you have come to my gate. In another, you,
crossing the garden, have found me dead.
In yet another, I say these very same words,
but am an error, a phantom."
-Jorge Luis Borges,
The Garden of Forking Paths

See also
http://www.albertorojo.com/misc/borges_mc.htm


Lee Corbin

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Jun 2, 2005, 8:19:39 PM6/2/05
to EverythingList
Bruno writes

> Le 02-juin-05, à 15:23, Lee Corbin a écrit :

> > [Stathis wrote]


> >> So if I am told that tomorrow I will be copied ten times and
> >> one of these copies will be tortured, I am worried, because
> >> that means there is a 1/10 chance I will be tortured.
> >
> > Good example, but I would say that you will be tortured with
> > 100% probability at some places, and tortured with 0% probability
> > at nine others. The characterization of a piece of matter "Stathis
> > is undergoing torture" is looked upon from the 3rd person as an
> > entirely physically characterized objective process.
>
> But here I agree with Stathis. What you say can be said with the throw
> of a dice. There *will be* a 100% probability that I will experience
> the result n (with n = 1, 2, ...6). And if I make the dice rolling a
> long time, by adding the Heisenberg uncertainties there will be (with
> the MWI) a 100% probability for each outcome. But before the experience
> I am in a maximal state of ignorance, and that gives usually P = 1/6.

Well, it *sounds* like you are agreeing with me, or rather, with
the idea that you will experience each outcome of the roll of the
dice. Let's be specific: you have agreed that on your 60th birthday
you will attend a large celebration in your honor, and will roll
a massive osmium die, amid cheers from all those assembled.
This is the only time that such money and effort will be expended
for the "Great Bruno Osmium Die Roll" (except for incidents of
extremely low measure elsewhere in the multiverse where aliens
intervene or God appears to demand it, etc.) The entire purpose
of my hypothesis here, is just so that we do not confuse this
particular roll of the die with any other of your life.

I agree: *you* will experience *each* outcome of the Die Roll.
You will even experience the event that the osmium die turns
into a cloud of dust (through a quantum fluctuation), but it's
key that this occurs with only infinitesimal measure compared
to the measures of the six Brunos who experience the usual 1..6
outcomes.

So aren't we in total agreement so far? If so, then I suggest that
the usual nuances and feelings associated with the phrase "there is
a 1/6 probability that I will experience n=3 (the Die shows a three)"
is highly misleading! It makes one think that something *could*
happen to one, but that in certain cases it does *not* happen to one.

The problem is actually one of *anticipation*. As naturally evolved
creatures, we are fashioned to anticipate the next moments. I have no
time now to get into it, but I don't think that this feeling of
anticipation really can be rigorously used; it's (unfortunately)
riddled with problems. Yet we are wired to observe it. So before
the great Die roll, you must anticipate seeing 1..6 and *not*
seeing the quantum fluctuation. Moreover, if one of the normal
six outcomes is associated with a very unpleasant experience,
you cannot help but think that it's similar to having a one in
six chance of the bad thing happening, and a 5 in 6 chance of
it not happening. But I think that's a lie: the truth is that
each outcome *will* happen. The only thing that gives you any
consolation is that the measure of the bad thing is only 1/6
while the measure of the good things is 5/6.

> I agree "it is you", but I follow Stathis' intuition that before the
> "splitting" the proba is 1/10 of being "that "you"".

While, on the other hand, I speak this way: you definitely will be
that "you", and you definitely will not be that "you". Both will
happen; it's not best to speak of it as a probability IMO.

> If not with comp you must accept that Bruno Marchal *is* Lee Corbin.

> I think we did arrive at that conclusion before, [didn't we]?

I would say that Bruno and Lee are not the same because they have
very different memories (and, also---I think it follows---different
kinds of OMs). Now if as one poster pointed out, I live long enough
(e.g. 10^10^10^10^10) then the state *I* will have will be one of
Bruno's. But so what? All that means is that Lee won't be there
and Bruno will be there. It's similarity of structure that matters:
that's why I must identify with the Lee of last month, but not
necessarily the Lee of 2025 (especially if he's been drafted into
the Army and gets really, really different kinds of experience).

> Suppose immortality (for the sake of the argument). Lee1 and Lee2 can
> become as different as Bruno and Lee now.
> I think you should consider me as a "you" right now. We were the same
> amoeba you know, a long time ago.

As I am saying, there is no "soul" or other divinely registered
serial number. The paths that Lee1 and Lee2 take could take them
clear out of the Lee Corbin fuzzy sphere in personality-space.
In which case *I* am completely not getting runtime from their
execution.

The only reason I resist considering you (Bruno) to be Lee, is that
over in Bruno, "I" have so many different memories and dispositions
that I'm not Lee any more.

Lee

Stathis Papaioannou

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Jun 2, 2005, 8:38:10 PM6/2/05
to lco...@tsoft.com, everyth...@eskimo.com
Lee,

Your comments touch on important issues. Having read the article on your web
page I think we may basically agree but there are some differences. If you
look at it from a third person perspective, continuity of personal identity
over time is not only a delusion but a rather strange and inconsistent
delusion. Nevertheless, in the manner of delusions, realising this
intellectually does not make the delusion any less real at the "gut" level
of first person experience. Using my example where I am to be copied 10
times tomorrow and one copy tortured, I view this as a 10% chance that I
will be tortured tomorrow. You point out that this is not really correct:
there is a 100% chance that one copy of me will be tortured and a 0% chance
that the other 9 copies will be tortured, and all 10 copies have an equal
claim to being "me". This is the objective truth, but that doesn't make me
feel any differently about the matter. I still feel that there is a 10%
chance I will be tortured, and I still feel relieved that I am one of the
lucky copies when tomorrow comes and I am not tortured. There is an
inconsistency here in that today I identify with all the copies and tomorrow
I identify with only one, but so what? As you say, that is how our minds
have evolved.

If the experiences of the copy who is to be tortured will eventually be
merged with those of the non-tortured copies, that changes the situation,
because then it is *guaranteed* that I will eventually experience the
torture. I would worry similarly if I were to inherit the experiences of any
unrelated third person; the fact that it is other copies of me who are
suffering does not in itself make any selfish difference.

--Stathis Papaioannou

_________________________________________________________________
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Stathis Papaioannou

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Jun 2, 2005, 8:54:40 PM6/2/05
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Hal Finney writes:

My issue was not with the fact that the experiences will be forgotten, but
with the fact that there is no conceivable way, from a first person
perspective, to distinguish the high measure days from the low measure days.
You could have a million people sharing one instantiation of an OM or one
person experiencing a million instantiations of an OM: for *that OM* it is
all the same.

--Stathis Papaioannou

_________________________________________________________________
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Lee Corbin

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Jun 2, 2005, 10:32:48 PM6/2/05
to EverythingList
Stathis writes

> ...I think we may basically agree, but there are some differences. If you

> look at it from a third person perspective, continuity of personal identity
> over time is not only a delusion but a rather strange and inconsistent
> delusion.

I'm not quite sure I understand why you say this. Do you only
mean that *continuity* can be manipulated, e.g., on the one hand
we suffer a discontinuity every night when we fall asleep; on
the other, in the future it will be possible to record your
Monday experience, your Tuesday experience, etc., and then
a few months later play them back in reverse sequence? (We might
even give the latter replays tremendous measure, so that so far
as the parameter *time* is concerned, almost all of your Mondays
occurred after your Wednesdays.

Or do you mean more?

> Nevertheless, in the manner of delusions, realising this
> intellectually does not make the delusion any less real at the "gut" level
> of first person experience. Using my example where I am to be copied 10
> times tomorrow and one copy tortured, I view this as a 10% chance that I
> will be tortured tomorrow. You point out that this is not really correct:
> there is a 100% chance that one copy of me will be tortured and a 0% chance
> that the other 9 copies will be tortured, and all 10 copies have an equal
> claim to being "me". This is the objective truth, but that doesn't make me
> feel any differently about the matter.

I agree completely. It's just that we have now advanced conceptually
so that our feelings no longer match what we know to be the truth.
We still feel that the Earth is stationary and the sun moves, but now
we know better. Likewise this feeling that you have a 10% chance of
experiencing X is not anything that we are going to be able to shake soon.

> I still feel that there is a 10%
> chance I will be tortured, and I still feel relieved that I am one of the
> lucky copies when tomorrow comes and I am not tortured. There is an
> inconsistency here in that today I identify with all the copies and tomorrow
> I identify with only one, but so what? As you say, that is how our minds
> have evolved.

Yes.

> If the experiences of the copy who is to be tortured will eventually be
> merged with those of the non-tortured copies, that changes the situation,
> because then it is *guaranteed* that I will eventually experience the
> torture.

Good point. To be precise let's say that tomorrow you will split into
the ten copies, one of which will be tortured. Then one *year* from
now merging is scheduled to occur. Therefore you behave differently?
I don't think you should. (You may *have* to because that's how we
are built, but you still shouldn't.)

As I like to say "just because you are not (locally) experiencing
something, doesn't mean it isn't happening to you". Suppose that
you don't know whether any merging is to ever happen. How should
that change the way you feel about your copy being tortured? Now,
I grant that you don't get the sweaty palms if there won't be
any merging, but to me that's just a base animalistic reflex action.
The truth is that *you* are in two places at the same time, and in
the other place you are hurting a lot.

The point is that *now* your duplicate is in pain. For purely
selfish reasons, this should be a big deal to you, I contend.
Whether or not eons from now some merging does or does not
take place shouldn't change your approval or disapproval of
physical events taking place now.

> I would worry similarly if I were to inherit the experiences of any
> unrelated third person; the fact that it is other copies of me who are
> suffering does not in itself make any selfish difference.

Two points. First, if it's an "unrelated third person", it becomes
very unclear what merging would mean. We ran into a little of that
with trying to obtain memories of having been a bat.

Second, I don't think that the sudden acquisition of memories is
nearly as big a deal as the actual, first-time-though gaining of
an experience. I would vastly rather be given the memories of
having been tortured than to actually experience it (and retain
the memory). (Some very nice thought experiments obtain when
one plays off experience vs. memory-acquisition.)

Lee

Stephen Paul King

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Jun 2, 2005, 11:10:50 PM6/2/05
to everyth...@eskimo.com
Dear Lee and Stathis,

I really do not want to be a stick-in-the-mud here, but what do we base
the idea that "copies" could exist upon? What if "I", or any one else's 1st
person aspect, can not be copied? If the operation of copying is impossible,
what is the status of all of these thought experiments?
If, and this is a HUGE if, there is some thing irreducibly quantum
mechanical to this "1st person aspect" then it follows from QM that copying
is not allowed. Neither a quantum state nor a "qubit" can be copied without
destroying the "original".

All of these threads so far seem to be assuming that the process that
gives rise to a 1st person experience and the content of the experience
itself are purely classical and can be faithfully represented by classical
systems. It is this assumption, I believe, that underpins the entire
classical Platonic thesis. Indications are that it has already been
falsified, by the same experiments that unassailably imply that Nature is,
at its core, Quantum Mechanical and not Classical and thus one wonders: "Why
do we persist in this state of denial?"

Stephen

----- Original Message -----
From: "Lee Corbin" <lco...@tsoft.com>
To: "EverythingList" <everyth...@eskimo.com>
Sent: Thursday, June 02, 2005 10:32 PM
Subject: RE: Many Pasts? Not according to QM...

snip

Stathis Papaioannou

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Jun 2, 2005, 11:24:59 PM6/2/05
to lco...@tsoft.com, everyth...@eskimo.com
Lee Corbin writes:

>The problem is actually one of *anticipation*. As naturally evolved
>creatures, we are fashioned to anticipate the next moments. I have no
>time now to get into it, but I don't think that this feeling of
>anticipation really can be rigorously used; it's (unfortunately)
>riddled with problems. Yet we are wired to observe it. So before
>the great Die roll, you must anticipate seeing 1..6 and *not*
>seeing the quantum fluctuation. Moreover, if one of the normal
>six outcomes is associated with a very unpleasant experience,
>you cannot help but think that it's similar to having a one in
>six chance of the bad thing happening, and a 5 in 6 chance of
>it not happening. But I think that's a lie: the truth is that
>each outcome *will* happen. The only thing that gives you any
>consolation is that the measure of the bad thing is only 1/6
>while the measure of the good things is 5/6.

It *is* a lie that only one outcome will happen; and the anticipation of
this lie is therefore a kind of delusion. But as you suggest, we are wired
up to believe these lies, and this occurs at a very basic level which cannot
be overturned by mere reason. While I am interested intellectually in a
rational and objective understanding of these matters, emotionally I am
interested in perpetuating the delusion that I am not actually the one
suffering, and I don't really care how this effect is achieved.

Russell Standish

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Jun 2, 2005, 11:39:03 PM6/2/05
to Stephen Paul King, everyth...@eskimo.com
I'm not convinced that the QM no-cloning theorem applies to
consciousness. We have no evidence one way or another that cloning is
possible. So it is reasonable to take it as a working assumption, and
work out the consequences (which is largely what Bruno has done), or
conversely take the opposite assumption and work out the
consequences. If either of these scenarios give different consequence
that could be tested by experiment, we are much better off.

Cheers

--
*PS: A number of people ask me about the attachment to my email, which
is of type "application/pgp-signature". Don't worry, it is not a
virus. It is an electronic signature, that may be used to verify this
email came from me if you have PGP or GPG installed. Otherwise, you
may safely ignore this attachment.

----------------------------------------------------------------------------
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Mathematics 0425 253119 (")
UNSW SYDNEY 2052 R.Sta...@unsw.edu.au
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Hal Finney

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Jun 2, 2005, 11:52:45 PM6/2/05
to everyth...@eskimo.com
Stephen Paul King writes:
> I really do not want to be a stick-in-the-mud here, but what do we base
> the idea that "copies" could exist upon? What if "I", or any one else's 1st
> person aspect, can not be copied? If the operation of copying is impossible,
> what is the status of all of these thought experiments?
> If, and this is a HUGE if, there is some thing irreducibly quantum
> mechanical to this "1st person aspect" then it follows from QM that copying
> is not allowed. Neither a quantum state nor a "qubit" can be copied without
> destroying the "original".

According to the Bekenstein bound, which is a result from quantum gravity,
any finite sized system can only hold a finite amount of information.
That means that it can only be in a finite number of states. If you
made a large enough number of systems in every possible state, you would
be guaranteed to have one that matched the state of your target system.
However you could not in general know which one matched it.

Nevertheless this shows that even if consciousness is a quantum
phenomenon, it is possible to have copies of it, at the expense of
some waste.

Hal Finney

Stathis Papaioannou

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Jun 3, 2005, 12:07:10 AM6/3/05
to step...@charter.net, everyth...@eskimo.com
Stephen Paul King writes:

>Dear Lee and Stathis,
>
> I really do not want to be a stick-in-the-mud here, but what do we base
>the idea that "copies" could exist upon? What if "I", or any one else's 1st
>person aspect, can not be copied? If the operation of copying is
>impossible, what is the status of all of these thought experiments?
> If, and this is a HUGE if, there is some thing irreducibly quantum
>mechanical to this "1st person aspect" then it follows from QM that copying
>is not allowed. Neither a quantum state nor a "qubit" can be copied without
>destroying the "original".
>
> All of these threads so far seem to be assuming that the process that
>gives rise to a 1st person experience and the content of the experience
>itself are purely classical and can be faithfully represented by classical
>systems. It is this assumption, I believe, that underpins the entire
>classical Platonic thesis. Indications are that it has already been
>falsified, by the same experiments that unassailably imply that Nature is,
>at its core, Quantum Mechanical and not Classical and thus one wonders:
>"Why do we persist in this state of denial?"

It is true that nature is quantum mechanical rather than classical, but I am
not aware that anyone has proved that the brain is not a classical computer.
If it is, then it should in theory be possible to get a functionally
equivalent copy by copying the computational state, rather than exactly
emulating the quantum state; rather as one can transfer the operating system
and files from one electronic computer to another, without copying the
original machine atom for atom.

--Stathis Papaioannou

_________________________________________________________________
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Lee Corbin

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Jun 3, 2005, 12:26:26 AM6/3/05
to EverythingList
Stephen writes

> I really do not want to be a stick-in-the-mud here, but what do we base
> the idea that "copies" could exist upon?

It is a conjecture called "functionalism" (or one of its close variants).
I guess the "strong AI" view is that the mind can be emulated on a
computer. And yes, just because many people believe this---not surprisingly
many computer scientists---does not make it true.

An aspect of this belief is that a robot could act indistinguishably
from humans. At first glance, this seems plausible enough; certainly
many early 20th century SF writers thought it reasonable. Even Searle
concedes that such a robot could at least appear intelligent and
thoughtful to Chinese speakers.

I suspect that Turing also believed it: after all, he proposed that
a program one day behave indistinguishably from humans. And why not,
exactly? After all, the robot undertakes actions, performs calculations,
has internal states, and should be able to execute a repertoire as fine
as that of any human. Unless there is some devastating reason to the
contrary.

> What if "I", or any one else's 1st person aspect, can not be copied?
> If the operation of copying is impossible, what is the status of all
> of these thought experiments?

I notice that many people seek refuge in the "no-copying" theorem of
QM. Well, for them, I have that automobile travel also precludes
survival. I can prove that to enter an automobile, drive it somewhere,
and then exit the automobile invariably changes the quantum state of
the person so reckless as to do it.

If someone can teleport me back and forth from work to home, I'll
be happy to go along even if 1 atom in every thousand cells of mine
doesn't get copied. Moreover---I am not really picky about the exact
bound state of each atom, just so long as it is able to perform the
role approximately expected of it. (That is, go ahead and remove any
carbon atom you like, and replace it by another carbon atom in a
different state.)

> If, and this is a HUGE if, there is some thing irreducibly quantum
> mechanical to this "1st person aspect" then it follows from QM that copying
> is not allowed. Neither a quantum state nor a "qubit" can be copied without
> destroying the "original".

This is being awfully picky about permissible transformations. I
have even survived mild blows to the head, which have enormously
changed my quantum state.

> falsified, by the same experiments that unassailably imply that Nature is,
> at its core, Quantum Mechanical and not Classical and thus one wonders: "Why
> do we persist in this state of denial?"

Probably for the same reason that some people continue to be Libertarians.
It's a belief thing---the way you see the world.

Lee

rmiller

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Jun 3, 2005, 1:18:10 AM6/3/05
to Stathis Papaioannou, step...@charter.net, everyth...@eskimo.com
Equivalence
If the individual exists simultaneously across a many-world manifold, then
how can one even define a "copy?" If the words match at some points and
differ at others, then the personality would at a maximum, do
likewise---though this is not necessary---or, for some perhaps, not even
likely. It's been long established that the inner world we navigate is an
abstraction of the "real thing"---even if the real world only consists of
one version. If it consists of several versions, blended into one another,
then how can we differentiate between them? From a mathematical POV, 200
worlds that are absolute copies of themselves, are equivalent to one world.
If these worlds differ minutely in areas *not encountered or interacted
with by the percipient (individual), then again we have one percipient, one
world-equivalent. I suspect it's not as though we're all run through a
Xerox and distributed to countless (infinite!) places that differ broadly
from one another. I rather think the various worlds we inhabit are
equivalent--and those that differ from one another do by small--though
perceptible---degrees. Some parts of the many-world spectrum are likely
equivalent and others are not. In essence, there are probably zones of
equivalence (your room where there are no outside interferences) and zones
of difference. Even if we did manage to make the copies, then there would
still be areas on the various prints that would be equivalent, i.e. the
same. Those that are different, we would notice and possibly tag these
differences with a term: decoherence. Perhaps that is all there is to
it. If this is the case, it would certainly explain a few things: i.e.
precognition, coincidence and "synchronicity."

R. Miller


rmiller

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Jun 3, 2005, 1:39:19 AM6/3/05
to lco...@tsoft.com, EverythingList, Giu1i0 Pri5c0
At 11:20 PM 6/2/2005, Lee Corbin wrote:
>Stephen writes
>
> > I really do not want to be a stick-in-the-mud here, but what do we
> base
> > the idea that "copies" could exist upon?
>
>It is a conjecture called "functionalism" (or one of its close variants).

"Functionalism," at least, in the social sciences refers to the proposition
that everything exists because it has a function (use). When that notion
came under attack in the 1960s, structural functionalists responded that
some things have "latent functions"--uses that we have yet to
divine. Functionalism follows Scholasticism which follows teleology. Not
particularly good science---or at least, not *modern* science.


> > What if "I", or any one else's 1st person aspect, can not be copied?
> > If the operation of copying is impossible, what is the status of all
> > of these thought experiments?

Still pretty robust. If you accept that a chronon has a dimension equal to
about 10^-43 seconds, then you'd have to concede that we exist as a "deck"
of copies through time. No big deal, but we ARE copies of the individual we
were 1 x 10-^43 seconds ago. If not, where's the "glue"?


>I notice that many people seek refuge in the "no-copying" theorem of
>QM. Well, for them, I have that automobile travel also precludes
>survival. I can prove that to enter an automobile, drive it somewhere,
>and then exit the automobile invariably changes the quantum state of
>the person so reckless as to do it.
>
>If someone can teleport me back and forth from work to home, I'll
>be happy to go along even if 1 atom in every thousand cells of mine
>doesn't get copied.

Exposure to a nuclear detonation at 4000 yds typically kills about 1 in a
million cells. When that happens, you die. I would suggest that is a bad
metaphor.

>Moreover---I am not really picky about the exact
>bound state of each atom, just so long as it is able to perform the
>role approximately expected of it.

Structural functionalism. When physicists converse at a bar, they talk the
language of sociology.


>(That is, go ahead and remove any
>carbon atom you like, and replace it by another carbon atom in a
>different state.)
>
> > If, and this is a HUGE if, there is some thing irreducibly quantum
> > mechanical to this "1st person aspect" then it follows from QM that
> copying
> > is not allowed. Neither a quantum state nor a "qubit" can be copied
> without
> > destroying the "original".

What if there is *no* original copy? Those that are familiar with
Photoshop would probably argue that each layer created is still an integral
part of the image. If you accept Cramer's transactional model, then what
*will* take place in the future will affect the state of the past. You
don't suppose Julian Barbour is on to something?

R. Miller

Saibal Mitra

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Jun 3, 2005, 9:21:36 AM6/3/05
to everyth...@eskimo.com, "Hal Finney"


This is actualy another argument against QTI. There are only a finite number
of different versions of observers. Suppose a 'subjective' time evolution on
the set of all possible observers exists that is always well defined.
Suppose we start with observer O1, and under time evolution it evolves to
O2, which then evolves to O3 etc. Eventually an On will be mapped back to O1
(if this never happened that would contradict the fact that there are only a
finite number of O's). But mapping back to the initial state doesn't
conserve memory. You can thus only subjectively experience yourself evolving
for a finite amount of time.


Saibal

Stephen Paul King

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Jun 3, 2005, 11:11:11 AM6/3/05
to everyth...@eskimo.com
Dear Stathis,

----- Original Message -----
From: "Stathis Papaioannou" <stathispa...@hotmail.com>
To: <step...@charter.net>; <everyth...@eskimo.com>
Sent: Thursday, June 02, 2005 11:55 PM
Subject: Re: Many Pasts? Not according to QM...


snip

> It is true that nature is quantum mechanical rather than classical, but I
> am not aware that anyone has proved that the brain is not a classical
> computer. If it is, then it should in theory be possible to get a
> functionally equivalent copy by copying the computational state, rather
> than exactly emulating the quantum state; rather as one can transfer the
> operating system and files from one electronic computer to another,
> without copying the original machine atom for atom.

I would not be so hasty to swallow Tegmark's argument that the brain can
not be anything other than a classical computer:
http://physicsweb.org/articles/news/3/7/19 But that is really not the point
I was trying to make. As you admit, Nature is quantum mechanical and
thus we have to be sure what our ideas about what subset of Nature is or is
not classical. The rules are different for these two realms. When we are
musing about copying our 1st person experience and considering the
implications, are we merely only required to "copy" the informational
content of those 1st person viewpoints, like some tape recording or MP3, or
are we also requiring tacitly that the means that those particular
information structured can to be ordered as they are?

We can wax Scholastically about the properties of relationships between
numbers forever and ever but unless our theoretics make contact with the
tangible world and represent faithfully those aspects that we have verified
experimentally, are we merely generating material for the next episode of
Sliders?

Stephen

Stephen Paul King

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Jun 3, 2005, 11:28:38 AM6/3/05
to everyth...@eskimo.com
Dear R.,

You make a very good point, one that I was hoping to communicate but
failed. The notion of making copies is only coherent if and when we can
compare the copied produce to each other. Failing to be able to do this,
what remains? Your suggestion seems to imply that "precognition, coincidence
and "synchronicity"" are some form "resonance" between decohered QM systems.
Could it be that decoherence is not an "all or nothing" process; could it be
that some 'parts' of a QM system decohere with respect to each other while
others do not and/or that decoherence might occur at differing rates within
a QM system?

Stephen

Stephen Paul King

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Jun 3, 2005, 11:41:34 AM6/3/05