The arrow of time

From: Jacques Bailhache <>
Date: Tue, 22 Jun 1999 15:49:14 +0100

Devin Harris wrote :
<<Remember my idea that all worlds branch or converge toward one future. .
Obviously crackpot. How 'bout when I dropped time as a dimension. No one has
posted a response to anything I have written.
I have been ignored. I posted ideas about the distant future being
determined or inevitable, and how that shapes the present, which got no
direct response.
Quantumly speaking, we know the past is not determined until we observe it,
as is true of the future. There isn't merely one past. So we can imagine the
wave function of all possible worlds in the past. The wave function is very
wide first considering the immediate past, yet as we look ever deeper into
the past, all the many possible worlds we can envision merge toward a single
beginning, common to all paths, the Big Bang. All possible worlds begin from
or near a common single state. Notice how that one inevitable distant past
shapes what we observe about the past. It shapes our present. It makes the
background radiation evenly distributed. It shows us one model of the past,
not many depending upon which direction we look, or on different days.
The common origin of all quantum worlds makes our past consistent and
contributes to the flow of time being consistent. It radically narrows the
wave function, as related to what is possible to have happened. Now look at
the future. What is possible in the immediate future is also wide. Consider
that the set of all possible futures narrows toward a single outcome, a
single state, just like the past. Notice how that single future would shape
our world, our present, just as the single state in our past shapes our
world. Notice finally that if the past only shaped the present, if the
future didn't shape the present, then what is possible; the wave function,
would expand radically into chaotic possibilities. Then, there would be no
rational laws of nature. >>
Interesting idea which is coherent with the idea according to which the
universe spreads from a Big Bang to a Big Crunch. But this raises a
fundamental question : what makes the arrow of time ? The fundamental laws
of physics are symetric concerning time. Theoretically, one could reverse
any event. But if a perturbation occurs, we don't get back the initial
state. This implicitely supposes that the perturbations propagate toward the
future, and not the past, because the past is fixed. What makes the
direction of th arrow of time could be the opposite direction of the nearest
fixation point, the Big Bang. This would mean that near the Big Crunch, the
arrow of time would point in the reverse direction, with a time stagnation
zone in the middle.
See also my web page : :
        Metaphysical reflections - The arrow of time
        Another important question about the models of the universe is time.
        Time appears to us like a linear succession with a causality
orientation, from causes to effects. But the physicists have discovered that
the fundamental laws of physics are temporally symetric. How could we
explain this ?
        The physicists explain this with what they call the second principle
of thermodynamics, according to which the total entropy (physical measure of
disorder) of a system can only increase.
        Let us examine what are the deep causes of this dissymetry. Let us
take an example.
        A vase falls on the ground and breaks into pieces. During the
falling, it obeys to an approximatively symmetrical law. If we thow it up it
will follow approximatively the same trajectory if we ignore the resistance
of the air. When it reaches the ground, the deceleration produces forces
greater than those making its cohesion, and it breaks into pieces. These
pieces, following symmetrical laws, fall down on the ground, producing
vibrations of sound (ordered agitation of molecules) and warmth (unordered
agitation). At the microscopic level, the agitation of the molecules also
obeys to symmetrical laws. So where does the dissymmetry come from ?
Couldn't we imagine that this phenomene happens reversed in time ? Let us
see what would happen then.
        A warmth and a noise would cause vibrations of the ground. But these
warmth and noise would not be any agitations of molecules but very
particular agitations, such that the resulting vibrations would throw up the
debris of the vase in such a way that they would gather and remake the
entire vase which is thrown up.
        Such an event is theoretically possible but we do not observe it.
Why ? The dissymmetry comes from the fact that the initial conditions of the
reverse processare so particular a very small perturbation would be enough
to prevent the result, but for the breaking, if the initial conditions are a
little different, the event would happen with little modifications.
        Let us imagine what would happen if a perturbation occurs. For
example, a fly flies near the falling vase. The resulting moving of the air
modifies a little the trajectory of the vase and the pieces will be little
        In the reverse case, the fly would modify the very particular
molecular agitation which cause the vibrations which throw up the pieces and
gathers them. This perturbated molecular agitation would not give this
result and will remain an ordinary warmth and noise.
        We can feel where is the dissymmetry. We spontaneously tend to
consider that the perturbations propagate toward future, and not past.
        If we considef that the laws of physics are not totally
deterministic and that a place remains for free will, we could conceive that
this free will could act on both directions of time.
        The experience shows that this free will acts only toward one
direction that we call future. Why couldn't it act toward past ? Maybe
because past is fixed and future is free, the universe is fixed at a
fixation point in the past, the Big Bang. The past being fixed, freedom
could only act on future.
        We could also imagine that there could exist several fixation
points, the nearer from now being in our past, our Big Bang. Some scientists
think that the expansion phase of the universe could be followed by a
contraction phase which will terminate by a Big Crunch, a reverse Big Bang
during which the universe will go back to its original state of primitive
atom. But during this contraction phase, the arrow of time will probably be
reversed, so that in fact it will be an expansion for those who will live at
this time, then the Big Crunch would not be the end of the universe but
another beginning with a time in reverse direction compared to our time,
these two universes going one toward the other and gathering in a phase of
temporal stagnation during which time would be approximatively symmetrical.
In fact, there would not be three separated phases but a continuity.
        Let us imagine how things could be perceived by an hypothetic living
being which would cross this temporal stagnation phase.
        At the beginning, when he is nearer from the Big Bang than from what
appears to him as the Big Crunch, time appears to flow in one direction,
from what he calls past to what he calls future. Then he begins to perceive
of inversion time some phenomenes. We perhaps already perceive a few
phenomenes of this kind, for example divination which could be memory of
future. He could also observe inversions between perceptions and actions,
then will become more and more these phenomenes frequents, and in
progressively he the zone will enter where will seem stagnation temporal the
symmetrical time him. sense normal the being like perceive will he what in
flowing but inversed not him seems time, Crunch Big the like perceives he
what than Bang Big the like perceives he what from nearer is he when,
beginning the At.

Jacques Bailhache
Y2K Centre of Expertise (BRO)
DTN: 856 ext. 7662
Tel: +32-2 729.7662, Fax: +32-2 729.7985
Visit my home page :

Received on Tue Jun 22 1999 - 08:22:30 PDT

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