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Re: [ontolog-forum] Model or Reality

To: Randall R Schulz <rschulz@xxxxxxxxx>
Cc: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Sun, 12 Aug 2007 14:48:35 -0500
Message-id: <p06230916c2e512fb3680@[]>
>On Friday 10 August 2007 16:17, Kathryn Blackmond Laskey wrote:
>>  In quantum physics, ...
>That's the one where if you claim to understand it you're lying?
>I kid, of course, and while I do find it fascinating, I can lay no claim
>to understanding the math of it. If the truth were known, it was my
>first modern physics class and my electrodynamics class that really
>pushed me out of electrical engineering into computer science.
>Anyway, there are some so-called "interpretations" of quantum theory
>that suggest a limited form of backward-in-time influence. I'm thinking
>of John Cramer's "Transactional Interpretation of Quantum Mechanics"    (01)

+1 ! My absolute favorite explanation of QM. Way 
more convincing (and intuitive) than the 
Copenhagen interpretation, with all its 
mysterious overlapping states and half-dead cats 
and collapsing wave functions and so on. See
for a pretty readable account.    (02)

>and his "Generalized Absorber Theory." In this interpretation, both the
>emitter and the absorber of a vector boson (a photon, e.g.) participate
>equally in the act of transmitting energy and momentum from the emitter
>to the absorber.
>As I understand it, Cramer asserts that the form of backward-in-time
>effect (that carried by the so-called "advanced" waves) cannot be used
>to communicate information, but it does seem to make clear that the
>future configuration of matter and energy in the universe has some
>influence over the ongoing evolution of an earlier configuration of
>some (other) matter and energy.
>Given the chaotic nature of our universe, especially the aspect
>of "sensitive dependence on initial conditions", a slight variation of
>the direction of the emission of a photon (and thus of the momentum
>transferred by that photon) of what we now see as the Cosmic Microwave
>Background could lead to initially very small but eventually vast
>change in the configuration of the matter and spacetime that was in the
>vicinity of the emitting atom way back when.
>Personally, I find it delightfully mind-boggling. It's a bit like the
>movie cliche where the protagonist, his head in the sniper's
>cross-hairs, is spared because he trips, or sneezes, or spots a $20
>bill on the ground and his sudden, unpredictable movement at the moment
>the sniper fires keeps him from being shot. Thereafter, much is
>different than it would have been had the sniper succeeded. So it is
>with our movements (our presumably voluntary movements) and their
>effect on which CMB photons we absorb and hence precisely how momentum
>is transferred from the big-bang era to the present.    (03)

But the delicious thing is the observation that 
(following special relativity), these are in fact 
contemporary over long enough distances. Put 
another way: from the photon's point of view, it 
takes no time at all to go any distance. So going 
backwards or forwards in time at the speed of 
light isn't really much of a big deal. At the 
speed of light, there is no time in the ordinary 
sense.    (04)

Which is one reason I love the Cramer picture.    (05)

Pat    (06)

>My recommendation? Go dancing! Hmmm... Maybe _that's_ why Feynman liked
>to dance? He was trying to alter the present via the long distant past!
>>  ...
>>  K
>Randall Schulz
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