hsf@hlexa.UUCP (11/01/83)
(c) Copyright 1983 by Henry Friedman
(Copying for personal use by users of net is authorized.)
The Arrow of Time (continued)
But what is it about human consciousness that imparts the
forward motion through time. Scientists are still
puzzling over this question; so I don't pretend to have the
complete answer. But it would appear that our awareness
flows in a serial, forward direction in time because of the
nature of memory. At any given moment, our consciousness
depends upon memory, including memory of the most recent
events that were experienced. And the brain's memory func-
tion is, by definition, to store a record of the past.
Therefore, at any given moment, the brain contains a record
of its prior states. If the reverse were somehow true, and
the brain were able to store a record of the future instead
of the past, it is likely that we would experience time as
flowing into the past. In a similar vein, if our conscious-
ness were to suddenly leap into either the future or the
past (of a time during our lifetime), we would probably be
totally unaware of the "leap," in either point in time. And
even if awareness suddenly transferred back to a moment
immediately following the original "leap," our brains would
probably contain no record of the event. In other words,
with no change to our memory, there would be no apparent
change to our flow of consciousness.
At a somewhat deeper level of meaning, our awareness of the
flow of time must depend on the very existence of causality.
The fact that our universe has a very significant (though
not absolute) causal nature means that the distribution of
events in time is neither completely random nor arbitrary.
Causality allows that when events at a given moment in time
can physically "communicate" with events in the immediate
future, there will often be a strong statistical correlation
between those events. In other words, events are largely
determined by the events that preceded them, even though --
from a point of view beyond spacetime -- both the past and
the future events are "always there." If there were no
causality, and if events in time were either completely ran-
dom or completely arbitrary, there could be no brain with an
orderly memory function. Of course, if such were the case,
not only wouldn't there be an orderly flow to time, but also
there probably wouldn't be any consciousness at all -- at
least not as we know it.
When I first read Gruenbaum's explanation of why time seems
to flow (at a time when I was searching for such an explana-
tion), and the full impact of what he meant "sank in," it
was an exciting moment. Physicist John Wheeler has said
that we live in a "participatory universe," that by our sub-
jective observation of reality and by constructing models to
explain reality, we actually help to create it. But I had
never before fully grasped the meaning of the idea that the
*passage of time* -- which is so basic to our entire picture
of existence -- has *no reality at all* apart from our cons-
ciousness. Of course, there are schools of philosophy which
conclude that there is no reality (or, at least, meaningful
reality) of any kind without consciousness (the old argument
of "if a tree falls in an uninhabited forest....") But
skirting (or begging) *that* question, I found the conclu-
sion mind boggling: that apart from conscious awareness, the
universe of spacetime is as static and unchanging as were
our strips of movie film spread out on the gymnasium floor.
In the fifth century B.C., Parmenides, a Greek living in the
southern Italian city of Elea, founded one of the earliest
formal schools of philosophy. Eleaticism, as it is known,
after the name of the city, held that reality is a single,
unified, undifferentiated, unchanging, unmoving whole. It
is said that at the age of 65, Parmenides traveled to Athens
to teach (his lectures were delivered in verse form) and
there met the then young philosopher Socrates. Socrates
asked Parmenides how he could believe that there was no pos-
sibility of motion when the senses proved otherwise.
Parmenides replied that if sensory appearances contradicted
the dictates of logic, he must conclude that the sensory
appearances are an illusion.
Zeno of Elea, Parmenides' major disciple, developed a series
of mathematical puzzles in order to prove that motion is
impossible. "Zeno's Paradoxes," as they are called, are
still well-known (although few seem to be aware of their
philosophical significance). One of the best known of these
paradoxes states that one cannot possibly travel from
point-A to point-B, because one must first travel half the
distance, then half the remaining distance, and so on, ad
infinitum. Our usual reaction to these paradoxes is: "It's
obvious that they have to be wrong; now let's see what's
wrong with them."
But in the light of the above discussion of the reality of
the modern physics laboratory, where time does not really
flow, the ancient teaching of Parmenides and Zeno acquires a
surprising degree of relevance, after all.
(End of Chapter)
(Series to be continued in Part 6.)
(Please note that the material in this series is developed
in a different order from the original table of contents.)