Lancelot R. Fletcher (lance@interactive.net)
Fri, 15 Oct 1999 00:31:45 -0500
Stephen,
Thanks for posting the Julian Barbour article from New Scientist. I have
pre-ordered Barbour's new book (The End of Time) -- you can get it from
Amazon.com or bn.com for about $17.50 -- it's due to come out in a day or
two). You might want to read an interview with Barbour at
http://www.edge.org/.
Based on a quick, first review, here are some reactions:
1. I was struck by the fact that Barbour wants to retain the big bang
theory within his timeless universe. You could call that wanting to eat his
cake and have it too, but it also strike me as a curious lack of imagination
within the framework of what is intended to be a bold departure (the
subtitle of his new book is something like "the next revolution in
physics"). One of the great advantages of envisioning the possibility that
the universe as a whole is without time is that it invites one to look
seriously for alternative explanations for the phenomena that are said to
give us the big bang theory. Barbour seems not to have ventured outside the
box in this respect.
2. Barbour does not seem to have a well-developed notion of local time and,
by the same token, he does not seem to have a coherent notion of the
possibility of action, which is one of the principle strengths of Hitoshi's
notion of local time. I may be mistaken about this, of course, since my
reading of the Barbour article was pretty cursory (as an advocate of slow
reading, I am apologetic for this). One of the things that leads me to this
conclusion, however, is Barbour's repeated statements that time is an
illusion. This is one of a number of examples:
>>All this seems a far cry from the reality of our lives. Where is the
history we read about? Where are our memories? Where is the bustling,
changing world of our experience? Those configurations of the Universe for
which the probability mist has a high density, and so are likely to be
experienced, must have within them an appearance of history-a set of
mutually consistent records that suggests we have a past. I call these
configurations "time capsules". <<
Perhaps I am mistaken, but this sounds pretty similar to the notion of a
"block universe" that Huw Price advocates in "Time's Arrow and Archimedes'
Point".
That impression is reinforced, I think, by the following example:
>>What is more, we are somehow directly aware of the passing of time, and we
see motion-a change of position over time. You may feel these are such
powerful sensations that any attempt to deny them is ridiculous. But imagine
yourself frozen in time. You are simply a static arrangement of matter, yet
all your memories and experience are still there, represented by physical
patterns within your brain-probably as the strengths of the synapse
connections between neurons. Just as the structure of geological strata and
fossils seem to be evidence of a past, our brains contain physical
structures consistent with the appearance of recent and distant events.
These structures could surely lead to the impression of time passing. Even
the direct perception of motion could arise through the presence in the
brain of information about several different positions of the objects we see
in motion.
And that is the essence of my proposal. There is no history laid out along a
path, there are only records contained within Nows.<<
Perhaps it is unfair to burden Barbour with the limitations of an example,
but what is most striking about the example is this notion of a static or
frozen arrangement. The problem, of course, with that image is that an
arrangement can be static or frozen, only in time. Barbour seems to think
that a timeless universe can also be described as "unchanging", but, if that
is what he thinks, it is a radical misconception.
3. Although Barbour distinguishes his theory from that of Lee Smolin, on one
crucial point they seem to agree -- which is the point that you mentioned in
your message to Jerry Malsam: they seem to agree in assuming that, if the
universe as a whole is timeless, it follows that all the finite parts of the
universe are also timeless. I think Hitoshi needs to be given enormous
credit for noticing this assumption, since for most people this appears so
obvious that it seems like a necessary truth, so they are not aware that
there is any possible alternative. And, in Time V, Hitoshi shows, with what
I think is an extremely elegant proof, that the absence of global time is
entirely constent with the existence of local time.
4. In this, as with so many other recent discussions about time in physics I
am left with the feeling that what is missing is an adequately grounded
philosophical critique of the notion of time. To the extent that Barbour
ends up with a notion of the world from which the possibility of action is
absent (which looks to me like the case), he has simply found himself driven
into the arms of Zeno of Elea. But, unlike Barbour, Zeno's intention was
not to argue that time and motion are non-existent. His intention was to
show that what I call "vulgar Pythagoreanism," the mathematical physics of
his time, involved a defective understanding of time and existence which
would necessarily drive one into these paradoxical conclusions. Every
important philosopher, from Parmenides, Plato and Aristotle, through
Descartes, Spinoza, Leibniz and Kant, has recognized that time cannot be a
thing, something that exists in the world. The most prevalent view --
certainly that of Spinoza, but largely shared by others -- is that time is a
measure of duration, while duration is the contingent mode of existence
proper to finite things. The universe cannot be finite, since "finite" is
imply a Latinate word for "limited," and if there is anything that limits
the universe, then there is something which the so-called universe does not
include, hence it is not universal. Therefore the universe is necessarily
infinite, but if duration is the mode of existence proper to a finite thing,
then duration does not pertain to the universe. The traditional term for
the mode of existence proper to an infinite thing is "eternity." Eternity,
however, is not correctly understood as "sempiternity," i.e. "existing
always." Sempiternity is simply an imaginational projection of contingent,
durational existence.
The great problem, philosophically, has been to understand the relationship
between the eternal and the durational modes of existence -- to understand
how the eternal and infinite nature of the universe is necessarily expressed
in the durational existence of apparently finite components. The great,
really extraordinary, merit of Hitoshi's work, in my opinion, is that he has
situated his approach to the questions about the nature of time in physics
and the problem of reconciling quantum mechanics and the general theory of
relativity in exactly the same "logical space" as the classical problem of
relating the eternal and durational aspects of the universe. This
correspondence of questions is what Aristotle calls "a beautiful
perplexity."
Lance Fletcher, President
The Free Lance Academy Foundation
http://www.freelance-academy.org
lance@interactive.net
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