RE: Decision theory

From: Jacques Bailhache <>
Date: Wed, 13 Jan 1999 19:06:55 -0000

        This exchange between James Higgo and Vic Stenger is interesting,
but I don't see the relation with my question : can we chose the proportion
of universes in which we decide to act in a certain way ? Or is this
proportion determinated by the laws of physics ?

        According to some theories (cf Penrose), the non-determinism of
quantum physics may act on our behavior. Some structures in our neurones
called microtubules might amplify the non-determinism of the level of a
particle to the level of neurons. The behavior of a single particle may act
on one neuron and then on our behavior.
        But the distribution of probabilities of the different possible
states of this particle is determinated by the laws of physics. So it seems
to me that the distribution of probabilities (and then also the proportion
of universes) of the different behaviors of the neuron and of the man is
also determinated by the laws of physics.

        It seems to me that to have a real possibility of chosing this
proportion, there must be another level of choice (for example : choice
between [choice between ride with care with probability 0.9 and ride without
care with probability 0.1] and [choice between ride with care with
probability 0.1 and ride without care with probability 0.9].

        To illustrate that : imagine that the world is a tree and you are an
ant climbing to it. In the Copenhague interpretation, you can chose to climb
to one branch or another. In Many Minds interpretation there are in fact
several ants and a given proportion of them climbs to each branch. The
choice could still have a signification if it means to chose which ant we
        In MWI, and if suppose that spirit does not exist in duration but
only in an instant, we could represent this as if there were some fixed ants
all over the tree. In this case the choice does not mean anything.
        But there could be a possibility of choice if there are several
potential trees (with different proportions associated to the branches, or
even a different structure of the ramifications) and if we can chose one
tree which becomes real.

        Concerning the exchange between James Higgo and Vic Stenger, the
idea of time arrow pointing in different directions is interesting. I wrote
a text about this idea :

        in english :
        in french :
        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
        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
        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
        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
        those making its cohesion, and it breaks into pieces. These pieces,
        following symmetrical laws, fall down on the ground, producing
        of sound (ordered agitation of molecules) and warmth (unordered
        agitation). At the microscopic level, the agitation of the molecules
        obeys to symmetrical laws. So where does the dissymmetry come from ?
        Couldn't we imagine that this phenomene happens reversed in time ?
        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
        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
        reverse processare so particular a very small perturbation would be
        enough to prevent the result, but for the breaking, if the initial
        are a little different, the event would happen with little

        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
        agitation which cause the vibrations which throw up the pieces and
        gathers them. This perturbated molecular agitation would not give
        result and will remain an ordinary warmth and noise.

        We can feel where is the dissymmetry. We spontaneously tend to
        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
        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

        We could also imagine that there could exist several fixation
points, the
        nearer from now being in our past, our Big Bang. Some scientists
        that the expansion phase of the universe could be followed by a
        contraction phase which will terminate by a Big Crunch, a reverse
        Bang during which the universe will go back to its original state of
        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
        another beginning with a time in reverse direction compared to our
        these two universes going one toward the other and gathering in a
        of temporal stagnation during which time would be approximatively
        symmetrical. In fact, there would not be three separated phases but

        Let us imagine how things could be perceived by an hypothetic living
        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
        from what he calls past to what he calls future. Then he begins to
        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
        then will become more and more these phenomenes frequents, and in
        progressively he the zone will enter where will seem stagnation
        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
        he what than Bang Big the like perceives he what from nearer is he
        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 :

> -----Original Message-----
> From: Higgo James []
> Sent: Friday, January 08, 1999 10:59 AM
> To: Jacques Bailhache
> Cc: ''
> Subject: RE: Decision theory
> Jacques Bailhache wrote:
> The problem is : can we chose the proportion of universes in which
> we
> decide to act in a certain way (for example to ride with care) ? Or
> is this
> proportion determinated by the laws of physics which rule the
> molecules
> of our neurons ?
> James Higgo replies:
> All that exists, exists in the block universe; you can choose to see the
> universe as containing choices, or you may prefer to view the question as
> meaningless (as I do). My view of the universe is put forward, clumsily,
> in
> the following exchange with Vic Stenger:
> Vic Stenger:
> Suppose humanity never evolved. There still will be supernovas
> that spew out
> particles in all directions and we need to explain why, greatly
> separated in
> space and not in contact, at least for ten billion years or so, this
> always
> happens in the same time direction. That is, we do not have
> some spewing out
> and some where the same particles converge to make a nice
> stable star, carbon
> turning back to hydrogen and deuterium, and so on. Or, why
> there are
> (apparently) black holes and no white holes (maybe the gamma
> bursters are
> white holes, now that I think of it). As Huw Price makes it clear
> (I'm reading
> his whole book a second time, and working on my chapter on
> time's arrow), this
> is an unexplained puzzle--why the universe has this highly
> improbable state at
> one extreme of the time axis and not the other, thus setting a
> universal arrow
> of time for macroscopic (but not microscopic) systems.
> Bayes that, my old man.
> Vic
> James Higgo:
> Like so many other paradoxes, the question Vic asks about
> supernovas having an arrow of time is shown to be meaningless
> when you adopt Deutsch's view that time is an aspect of the
> relationship between 'snapshots' (individual 3-d universes) in the
> 'multiverse'.
> Time's arrow points forwards, backwards, everywhichwayyou like
> in the multiverse - it just depends on how you want to look at it.
> Supernovas would 'exist' without us, but only if someone chose to
> string snapshots together so they saw supernovas. It's an infinite
> multiverse, but unless someone is looking along some axis, it is
> meaningless to say this or that exist. Everything possible exists.
> We ourselves only exist in some of the tiny fibres of inter-
> universe connections along which time's arrow happens to point
> forwards, along which 'cause' precedes 'effect'. Because,
> although the multiverse is infinite, we could only exist in this sort
> of stable environment, where lots of things don't 'decay' at once.
> Decay is not the phenomenon; that any two particles appear to
> be related is the rarity. But in an infinite multiverse...
> It is pointless to talk about 'supernovas' *per se* - they are merely
> a function of the way we string universes together. But there are
> very few such strings that would result in 'environments' in which
> llife would evolve; of those, most if not all involve supernovas.
> Vic Stenger : This explanation borders on solipsim. It explains everything
> by explaining
> nothing. We see no white holes or imploding supernovae in our universe.
> Sure
> this could be because this is just a statisical fluctuation. The average
> universe has half of each and we are way out on the tail of the
> distribution.
> This is very unsatisfying. Just giving up. "Everything is possible." You
> are
> welcome to do that. I would prefer to keep trying to see if there is some
> non-random reason for what we see in our universe. I do not think the WAP,
> as
> you use it with your fibers above, is enough.
> James Higgo: Vic, you may say that recourse to the WAP (weak anthropic
> principle) is 'giving up'. But in the context of MWI it explains
> everything, such as the absence of vacuum collapses and all
> sorts of nasties. It is also the basis for the wacky quantum theory
> of immortality, which is another reason for you to be prejudiced
> against it. You seem to be denying the validity of WAP, which
> makes intuitive sense, as piously as most people deny time's
> arrow can point both ways. It isn't as 'satisfactory' as a nice
> experimental 'proof' but what if this is as good as it gets? Perhaps
> the universe was not designed for satisfaction.
Received on Wed Jan 13 1999 - 11:37:49 PST

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