Re: The Road with no Branches argument

From: Acme Diagnostics (LFinezapthis_at_partpostmark.net)
Date: 10/28/04 

Date: 28 Oct 2004 03:43:12 -0500

"Milan" <mtklima@yahoo.com> wrote:
>"Acme Diagnostics" <LFinezapthis@partpostmark.net> wrote in message
>news:41800e8c$0$25034$45beb828@newscene.com...
>
>Hawking says the following in A brief history of time:
>
>"These quantum theories are deterministic in the sense that they give laws
>for the evolution of the wave with time. Thus if one knows the wave at one
>time, one can calculate it at any other time. The unpredictable, random
>element comes in only when we try to interpret the wave in terms of the
>positions and velocities of particles. But maybe this is our mistake: maybe
>there are no positions and velocities, but only waves. It is just that we
>try to fit the waves to our preconceived ideas of positions and velocities.
>The resulting mismatch is the cause of the apparent unpredictability."

Thanks. It's very important and nice to read it again. It
would be nice if "unpredictable, random" were qualified more
exactly. Perfectly random? Unpredictable as to one path/position
or having no probability of various paths/positions?

My last anthological physics update was "The Elegant Universe"
though I've read this or that web page since, including the above
Hawking quote. Whenever the subject led to the question of
lawfulness I paid careful attention, especially in the discussion
of probability distributions of particle motion.

I could not identify one case of unlawfulness and in fact it
seemed that the author was refuting same here and there more
specifically than Hawking, and with respect to positions, not
just waves, and explaining why the uncertainty principle did not
translate to unlawfulness. In every case, the particle would
follow various paths with exact probabilities, sometimes all
paths at the same time (!!) with certain probabilities, but the
probability functions were always satisfied, i.e. the behavior
was lawful. But of course any particular path, or that there was
just one path, or even the state of the particle at any given
time, was unpredictable and, in that sense, random.

I did get a sense of the incredible chaotic nature of the quantum
soup and how, intuitively, it would seem impossible for there
to be any lawful generalization to higher levels of description.
But until informed otherwise, I maintain that complexity alone is
insufficient basis for unlawfulness.

Since I'm not a physicist, this doesn't mean much. But it helps
to understand quotes such as Hawking's and perhaps form better
questions when I have an opportunity to ask an expert. The best
group to ask such questions is (oddly) rec.arts.sf.science and
I've been meaning to do that ever since the recent Hawking
announcement wrt black holes, even warning them (<g>), but
haven't gotten around to working up a good question.

Larry