Dear Tim,

    Thank you for the reply but ... Well, I did not mean to imply that we
should "look to Egan's fictional character for actual theories" or any other
novel or fiction... I think that I asked you a similar question before
regarding the idea that Egan is discussing using the fictional character of
Mosala. I am trying to see if you understood the idea well enough to discuss
it with me. It seems that my question below got missed somehow.
    Scerir mentioned the following paper previously:

http://arxiv.org/abs/quant-ph/0110124

Quantum Physics, abstract
quant-ph/0110124
From: Antoine Suarez <[EMAIL PROTECTED]>
Date: Sat, 20 Oct 2001 13:02:58 GMT   (17kb)

Is there a real time ordering behind the nonlocal correlations?
Authors: Antoine Suarez
Comments: 4 pages Latex, 1 eps figure

  It is argued that recent experiments with moving beam-splitters
demonstrate that there is no real time ordering behind the nonlocal
correlations: In Bell's world there is no "before" and "after".
    If you get a chance to read it perhaps my terms "a priori" and "a
posteriori" might make some sense. ;-) I have been looking for Smolin's book
in my local bookstore. I will try again. Incidentally, I have read books by
most of the writters you mention! I too am very fond of Zindell's Neverness.
;-)

Kindest regards,

Stephen


----- Original Message -----
From: "Tim May" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, September 04, 2002 12:24 PM
Subject: Re: Time as a Lattice of Partially-Ordered Causal Events or Moments


>
> On Wednesday, September 4, 2002, at 07:47  AM, Stephen Paul King wrote:
>
> > Dear Tim and scerir,
> >
> >     I am VERY interested in this discussion! ;-) It seems to me that
> > fact
> > that the amplitudes of observables in QM are complex valued and thus
> > do not
> > obey trichotomy may be at the root of the difficulty. When we attempt
> > to
> > make sense of situations such as those we obtain in EPR we have to be
> > very
> > careful that we take into account the configuration of the experiment
> > itself. This implies that the lattice of relations or poset aspect of
> > causality is a posteriori and not a priori to the specifics of the
> > experiment. This implies, at least to me, that it is a mistake to
> > assume the
> > a priori existence of a space-time (with a unique light cone
> > structure).
>
> I agree that imposing a space-time structure for quantum events is a
> problem. In fact, this is one of the motivations of quantum gravity
> work, to get rid of the "events on a background of space and time"
> which most QM has been using.
>
> However, assuming a space-time and with local light cones seems very
> reasonable to me. We have no particular evidence that the light cone
> formalism isn't still applicable to quantum kinds of events (whatever
> EPR "spooky action at a distance" may be, there is certainly no
> evidence that faster than light travel of particles or photons is
> involved, so there's no reason to throw out the speed of light as a
> maximum speed).
>
> You may be interested in Smolin's "Three Roads to Quantum Gravity." He
> argues for the _relational_ view of space-time as being more suitable
> than the absolute space-time coordinates in Newtonian and (ironically)
> most quantum theories. Relativity of course uses the less absolute
> scheme.
>
> However--and this is very important!--there are no theories given
> experimental support today which show real violations of causality. (We
> could debate for a few days whether delayed-choice experiments,
> Aharonov-Bohm experiments, etc. show violations of causality. While
> entangled states show behaviors not found in the macroscopic,
> classical, human-scale world, they don't violate causality.)
>
> This argues for the emphasis placed on causal sets and causal
> relations. And hence on posets and lattices. (In my opinion, following
> the lead of the several authors I've mentioned a few times here.)
>
> >     One possible solution is to consider space-times strictly from an a
> > posteriori point of view. You had mentioned Greg Egan's novels and the
> > "All
> > Topologies model" (for instance in the novel Distress) in previous
> > posts. Do
> > you think that the ideas of the character Mosala could be used to "make
> > sense" of this?
>
> Well, I try not to get too many of my theories out of science fiction!
>
> Not to sound flip or dismissive, but Egan's novels and short stories
> are best seen as romps through a landscape of strange and stimulating
> ideas. I like his stuff a lot because he's one of the few writers today
> able to (or interested in) keep up with modern physics and modern math.
> There was a time when SF writers were engineers or scientists (Asimov,
> Heinlein, Clarke, Hal Clement, even Larry Niven, who was at Caltech for
> a while). Their editors were also science-oriented people, like Hugo
> Gernsback and John Campbell, who wanted hard science in the science
> ficiton they bought.
>
> In their day, these authors wrote stories and novels involving the
> then-weird ideas of hypercubes, Mobius bands, planets with extremely
> high gravity, time travel, neutron stars, and black holes. (Larry Niven
> was the Greg Egan of his day. Niven still writes, but his recent novels
> are less compelling and certainly no longer are exploring cutting-edge
> stuff.)
>
> As SF spread in popularity to the Baby Boom generation, more and more
> non-scientists and non-engineers started writing. So we got more
> "sociological" SF (some of it very good, like Ursula LeGuin's stuff).
> And more of the "palace intrigue" kind of novels ("The planet Cthwox
> has been ruled by the Klanring for 2000 years. A spaceship from the
> Vegan Federation has arrived..."). And then there is fantasy...dragons,
> magic, etc.
>
> A few writers have stuck to hard science themes. Vernor Vinge is a good
> example. And some of the "cyberpunk" themes have been more or less
> based on plausible science, including Gibson, Walter Jon Williams,
> Bruce Sterling, Dan Simmons, etc. (I also like a less popular author,
> David Zindell, and his quartet of novels set on the planet "Neverness."
> Mathematics plays an unusual role.)
>
> Steven Baxter also writes Stapletonian novels about the distant future
> and the end of time, though his themes are often depressing (to me at
> least).
>
> Greg Egan is one of the few writers today actually _using_ the latest
> developments in physics and even math to explore ideas about the nature
> of our reality, the anthropic principle, and the colonization of
> cyberspaces.
>
> It also turns out that Egan has been doing some Java and Mathematica
> programming for some of the spin foam papers by Baez and others. This
> doesn't mean that any particular idea he explores, whether in
> "Distress" or "Diaspora" or "Schild's Ladder," is "right," just that
> Egan is obvious technically competent to write about these ideas.
>
> What fired me up about "Distress" in particular was the several-page
> synopsis of the "All Topologies Model." For some reason, this got my
> juices flowing. (The rest of the novel just sort of plodded along to a
> fairly predictable conclusion.)
>
> I hope this explains why I don't look to Egan's fictional character for
> actual theories, just stimulation.
>
> --Tim May
>
>


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