Hitoshi Kitada (email@example.com)
Sat, 17 Apr 1999 02:25:57 +0900
I saw some books on quantum measurement, and turned to thinking that the
Wheeler's quantum eraser seems correspond just to the difference of observed's
system L xor L'. I.e. it does not seem to relate with the influence of the
present observation to the future observation at least according to my
reading. Thus the following argument of mine seems not valid in the original
form, although there may be a possibility that the nonlocality property of QM
might recover some of the argument in other forms.
----- Original Message -----
From: Stephen P. King <firstname.lastname@example.org>
Cc: Time List <email@example.com>; Lancelot R. Fletcher
Sent: Friday, April 16, 1999 1:19 AM
Subject: [time 232] Re: [time 229] Direction of time or Free will
> Dear Hitoshi and Friends,
> Thank you for possessing this problem. :) It is one that I have been
> thinking about for a long time. First I have some clarification
> Hitoshi Kitada wrote:
> > Dear Time Folks,
> > Let me propose a problem about the direction of time, which, at least
> > seemingly, has a form that has not been considered before. That is partly
> > reminiscence of [time 199] and hinted by Ben's remark [time 198].
> > Direction of time or Does the free will exist?
> > Let us consider the following observation:
> > Let an observer O observe a local system L'=(L1,L2,X) or L=(L1,L2). Here
> > and L2 is the direct objects of observation of O and X is some automatic
> > apparatus that observes the system L=(L1,L2).
> Here we have a choice of observables, L or L'; I am assuming that they
> are observationally mutually exclusive, e.g. O observers L xor L'.
> How are O and X defined in terms of local systems? They seem to be
> classical and, upon thinking further, X looks to be another observer
> itself. Perhaps we can think of it as one of Peter's "secondary
> observers"... ( cf. [time 191])
> > In this situation, Wheeler's quantum eraser illustrated in Ben Goertzel's
> > GOERTZEL.html (http://goertzel.org/dynapsyc/1995/GOERTZEL.html):
> > > In fact, according to (Wheeler, 1980), this even works
> > > if the choice is <b>delayed</b> -- then one has the phenomenon
> > > of the "quantum eraser." In other words, suppose one has a
> > > <b>machine</b> record which slit each particle passed through.
> > > If after a few hours one destroys the machine's records
> > > without having looked at them, and only <b>afterwards</b>
> > > looks at the plate, then result is the same as if the
> > > information had never existed; the plate shows that the
> > > particles behaved like waves. But in the same scenario, if
> > > one looks at the machine's information before one erases it,
> > > the picture on the plate is quite different: it is consistent
> > > with whatever the machine said.
> > may be restated as follows:
> > If O looks at L', then what O sees in the future about L
> > is different from what O sees when O looks only at L. (1)
> Here it seems that the meaning of "past" and "future" needs to be
> carefully examined. Can we understand this terms "sees" as meaning
> logically inference? I am trying to think of this in terms of Peter's
> Interactive Machine paradigm. If we could show that a LS is equivalent
> to a finite IM, we could easily bring in the power of Peter's analysis
> in to play. :) http://www.cs.brown.edu/~pw/papers/bcj1.pdf
> > We may regard this as an experimental fact (provided that the situation
> > describes exactly Wheeler's quantum eraser).
> > Wheeler's case may be rephrased:
> > The present affects the future. (1')
> Is this meaning strict material causation, in the sense that a
> primitive lightcone structure could be constructed using an array of
> Observers O_i exchanging signals. It is the "thermodynamic arrow" that,
> I believe, holds the key to thinking of an asymmetry between evolutions
> toward the past or future. But on a side note, independent of any
> observation, an LS's time arrow can only be considered as having a
> superposition of directions. This relates to my earlier questions about
> time vectors. :)
> > Let us consider the observation with time order reversed. The question in
> > case is if the following is correct or not:
> > If O looks at L', then what O sees in the past about L
> > is different from what O sees when O looks only at L. (2)
> > This would be paraphrased:
> > The future affects the present. (2')
> We are starting to think seriously about the ontological question of
> causation and temporal transitivity! :) It is well known, that systems
> described by invertible dynamics do not have an "arrow of time" (cf. M.
> C. Mackey "Time's Arrow: The Origins of Thermodynamic Behavior".
> Springer-Verlag, 1992 http://www.cnd.mcgill.ca/bios/mackey/mackey.html);
> we need to look at the scattering state dynamics of LSs to see if they
> satisfy "f* exactness" or some equivalent.
> I believe that there is there is an analogy between the difference
> between "bound and scattering states" and Mackey's "dynamical systems
> and traces" (pg. 111 ibid.) and thus there is a way of defining LSs as
> having a define time arrow.
> > Turning to the direction of time, I think it may be understood as the
> > direction of one's own time when he sees the outside. If we understand the
> > direction of time in this way, we have two alternatives with (2):
> > If (2) is true, then the observer's time is reversible,
> > while
> > if (2) is false, then the observer's time is irreversible.
> > (2) may be tested by experiments, similarly to Wheeler's.
> > If the direction of time is that of the observer's subjective time as I
> > proposed, my claim is thus that we can find by experiments if time has the
> > direction or not.
> Of course, it is the act of observation that implies that a fixing of
> frame has occurred and that such fixes a chronological ordering. But, we
> can *not* assume such distributive orderings exist *ab initio*, since
> the computation of such is an NP-Complete problem and thus is
> irreducible to mere postulations of "microcausality".
> > This might sound a silly assertion, as we feel we experience the direction
> > time in daily life. But the statement (2) could be a direct test of
> > of subjective time, and I think the direction of time has not been
> > this way.
> > Another point about (2) is that, if (2) is true, we have to think it
> > that all is inevitable fate, or all is determined but we cannot know which
> > result actually occurs. This point would be illustrated by the following
> > passage adapted from [time 199]:
> > We assume (2) is true.
> > An observer O is informed that an apparatus X records some data about his
> > objects L1 and L2, but does not see the data on X. He makes observation
> > of L=(L1,L2). Then he is planned to walk a corridor to the point where the
> > corridor forks into two directions. Beforehand another person brought the
> > apparatus X at the end of one of the two corridors. Whether or not
> > he (observer O) sees X at the end of the corridor depends on his
> > choice which corridor he takes. If he knows that his observation of L is
> > the same as the data that he will see the apparatus X, then he knows
> > that he will choose the correct corridor where the apparatus X is at
> > the end, whichever way he takes. Or if he knows his observation does
> > not match those data, he knows in advance he will choose the wrong way.
> > In short, _if (2) is true_, O must choose one right way always, whichever
> > direction he takes at the branch, if the data coincide with those that he
> > see the apparatus X. He _can_ choose one of the two at his will, but his
> > choice has been determined in the sense that he has _no ability_ to change
> > fate to see the apparatus X.
> > So if (2) is true, no free will exists,
> > or
> > if (2) is false, the free will may exist.
> Are we defining free will as strictly contradicting determinism at all
> levels, could we have free choise externally and determinism interiorly
> to LSs?
> In Computer science we distinguish between "linear time" and "branching
> time" computations. The former assume complete initiality ab initio
> ("all choices made at the outset") and the latter eliminates initiality
> requirements ("choices made on-the fly to take into account the latest
> It seems that if we consider that LSs "evolve", then it is not trivial
> to consider that we could think of them as "adaptive" systems, and such
> adaptations can well represent branching time types of computations.
> > I.e.
> > if the direction of time does not exist, the free will does not exist,
> > or
> > if the direction of time exists, the free will may exist.
> > This problem may relate with the Classical/QM features of our world: Even
> > (2) is true, we have our free will at each stage (QM aspect), but the fate
> > a whole is determined (Classical aspect). If (2) is not true, then such
> > restrictions do not exist and we might have true free will.
> We are faced here with the ontological question of the "reality" of an
> it-itself unknowable quantum mechanical Universe and whether its finite
> subsets can be known. The method of how knowledge evolves is itself
> exposed to analysis.
> > Hitoshi
> Onward to the Unknown,
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