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<DIV><FONT face="Courier New" size=2>Stuart writes</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face="Courier New" size=2>> --- Stathis Papaioannou <<A
href="mailto:stathisp@gmail.com">stathisp@gmail.com</A>> wrote:<BR>>
<BR>>> The splitting can be said to occur while they were separated,
but<BR>>> should we say that they were in the same universe they are
revealed</FONT></DIV>
<DIV><FONT face="Courier New" size=2>>> to be in when they meet even while
they were separated?</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>Stathis, let me see if I am interpreting
your question correctly.<BR>First, I thought that the Alices and Bobs did stay
physically<BR>separated from each other, so that you probably mean at<BR>a time
before some signal went from a particular Alice event<BR>A to a particular Bob
event B, after which we do understand<BR>them to be in the same universes, (i.e.
A1 and B1 as henceforth<BR>ongoing persons can reliably communicate with each
other<BR>and marvel that their photons did come out the same way,</FONT></DIV>
<DIV><FONT face="Courier New" size=2>way back when).</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>So let's say that A becomes A1 and A2, and
B becomes B1 and B2,</FONT></DIV>
<DIV><FONT face="Courier New" size=2>and the question is, should we say that A1
and B1 are</FONT></DIV>
<DIV><FONT face="Courier New" size=2>immediately in the same universe, even
though the splits<BR>caused at A and B haven't yet had time to reach each
other<BR>and match up? I suppose that yes, we could say that A1 and
B1</FONT></DIV>
<DIV><FONT face="Courier New" size=2>(pre-any signal having gone from any A to
any B) are in the</FONT></DIV>
<DIV><FONT face="Courier New" size=2>same universe now, since they're fated to
be anyway.</FONT></DIV>
<DIV><FONT face="Courier New" size=2>But I'd be agin it because</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New"
size=2>\
/<BR> a--------------b<BR>/
\</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>the splits that are (very roughly speaking)
still<BR>separated (in someone's reference frame) by the<BR>distance ab and
which are moving towards each other<BR>don't make it clear *by definition* that
the upper<BR>slashes will turn out to be together in the one universe<BR>and the
lower slashes will turn out to be in the<BR>other universe. That the photon that
was measured<BR>somewhere to the left of the diagram will have
outcomes<BR>exactly parallel to the EPR-entangled one measured<BR>somewhere to
the right of the diagram, is a deduction<BR>or at least a mathematical
consequence. </FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>>> It seems to me that the Alice
outside Bob's light<BR>>> cone who will eventually be demonstrated to be
in<BR>>> "same" world is just as unreachable, just as<BR>>> causally
isolated from him as the Alice in the<BR>>> "other" world.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>Yes, I agree.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>>> Perhaps this could be dismissed as
a mere<BR>>> philosophical point, but it does emphasise<BR>>> that
no FTL communication is possible or<BR>>> necessary.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>Anything to help with that! But it may
simply do,<BR>to say that A1 and B1 *will* be in the same universe<BR>after
their splits join up, rather than announcing<BR>that they're beforehand already
in the same universe.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>Stuart writes</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>> I don't see why people would have a
problem<BR>> with the possible FTL nature of a correlation<BR>> in the EPR
experiment, or wave-function collapse,</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>It's incomprehensible on the theory of SR,
that's why.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>> but have no problem with the idea of
the entire<BR>> universe being causally split in the mere seconds<BR>> it
takes for someone to make a measurement,</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>The whole universe never ends up being
split in its<BR>entirety unless it's of finite extent. The splits<BR>start
locally and speed outwards only at c.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>> each and *every* time a measurement is
made.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>It *is* a horrible zoo; David Deutsch says
on p. 213<BR>of "The Fabric of Reality":</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2> "...rely on such things as
solid matter or<BR> magnetized materials, which could not
exist<BR> in the absence of quantum-mechanical
effects.<BR> For example, any solid body consists of
an<BR> array of atoms, which are themselves composed<BR>
of electrically charged particles (electrons,<BR> and protons in the
nuclei). But because of <BR> classical chaos, no array of charged
particles <BR> could be stable under classical laws of
motion.<BR> The positively and negatively charged
particles<BR> would simply move out of position and crash
into<BR> each other, and the structure would
disintegrate.<BR> <BR> *It is only the strong quantum
interference <BR> between the various paths taken by
charged<BR> particles in parallel universes* that
prevents<BR> such catastrophes and makes solid matter
possible.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>So any solid object is making nearly
infinitely<BR>many measurements each nanosecond, and those "splits"<BR>radiate
away at c, so that the whole fabric of reality<BR>is a seething jumble of
massive interference everywhere.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>> Perhaps one of the Everettistas could
explain this to me.<BR>> If the split starts at Alice and travels at c toward
Bob,<BR>> if Bob is space-like separated it won't ever reach
him.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>We have to be clear about the difference
between an event<BR>Bob-X and the ongoing entity Bob who retains the
characteristics<BR>of a physical object. Say the split starts at
Alice-Y,<BR>Alice is then hit by a truck, but the split goes on<BR>(especially
if it's evil, as the old saying goes) and<BR>reaches not the Bob-X what was
interviewed at a point<BR>along his timeline where it was deemed that
Alice-Y<BR>was outside his light cone, but instead reaches Bob<BR>when he's at a
different point (say z, so it's Bob-Z). </FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>> If you imagine that the universe is a
sheet of paper,<BR>> it doesn't matter what dimension you split it
in,<BR>> whether you simply rip it in half or peel it apart<BR>> along the
plane, the split still has to travel at<BR>> some finite speed.</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>Yes, and it travels at the speed of c.
</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2> "Although the points of
measurement indeed are few"<BR> (remarked the late Professor
Grew)<BR> "Instead of all four worlds created anew<BR>
We only get but two!" [1]</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV><FONT face="Courier New"
size=2>
<DIV><BR>> Or let's say it's simply the information in the<BR>> universe
that is splitting like a file being copied.<BR>> The larger the file, the
longer it will take to be<BR>> copied, even if you don't edit the file to
make sure<BR>> that one of the particles had its spin reversed.</DIV>
<DIV> </DIV>
<DIV>Yes, could be like that.</DIV>
<DIV> </DIV>
<DIV>> Of course if MWI is *magical* or something, then I suppose the<BR>>
splitting makes sense.</DIV>
<DIV> </DIV>
<DIV>Hopefully not any *instantaneous* splitting.<BR>Not enough evidence to go
against SR yet.</DIV>
<DIV> </DIV>
<DIV>Lee</DIV>
<DIV> </DIV>
<DIV>[1] With respect to Dr. Paine, who was of triangle poetry fame,<BR>and who
didn't, I suspect, really have a daughter Rachel by name,<BR>(Damn, the little
ditty used to be on-line, but I can't find it now.)</FONT></DIV></BODY></HTML>