GSLevy.domain.name.hidden wrote:
>
> In a message dated 05/21/2000 7:59:35 PM Pacific Daylight Time,
> R.Standish.domain.name.hidden writes:
>
> > http://parallel.hpc.unsw.edu.au/rks/pubs.html
>
> >The necessity comes from the requirements of the anthropic principle,
> however >when a particular aspect of the universe is not constrained by the
> AP, its value >must be decided by chance (according to the SSA) the first
> time it is ``measured'' >by self-aware beings.
>
> I may have misunderstood you Russell, but the above statement from your paper
> reminded me a lot of Wheeler's participatory universe with which I strongly
> disagree. You are saying here that a parameter not constrained by the AP will
> take a value as soon as it is observed by observers. Your use of plural in
> "Self Aware Beings" is confusing. Does it take observations from several
> beings to collapse that parameter? What do beings observe, who have not been
> instrumental in this collapse?
OK, I'll try to chase up a ref about Wheeler's ideas to see what
relationship, if any there might be. I hate being misunderstood :)
As for your second question, perhaps I can clarify it with a simple
example of two observers, looking at a binary observable:
Observer A and Observer B share a common history up until time t0, at
which point A examines the binary variable x. This implies that if A
talks to B, they will agree on all values of observations in their
environment. After time t0, there are two distinct histories for
observer A, which we call A0 and A1, depending on whether x is 0 or
1. To observer A0, B should agree the value of x=0, but doesn't know
it yet. Conversely, A1 thinks that B should agree the value is x=1. At
time t1, B makes an observation of x. There will now be two histories
- one in which A0 agrees with B0 that x=0, and another one where A1
and B1 agree that x=1. The history where A0 discusses the measurement
with B1 is ruled out. (Assuming, for the sake of argument, that the
measurements were perfectly reliable). There will also be a history
where B measures a totally different variable y at t1.
So the answer to your question is that there may well be more than 1
observer involved in setting a particular history (all observer need
to agree consistently on all aspects of the history in order to
communicate - ie a "Don't know" is consistent with any particular
value, but when I later go to measure the value, it should be the same
as what you told me). However, it is not necessary for there to be
multiple observers. Many aspects of my observational history will
remain private and unknown to any other observer.
The thing about the many worlds (or many histories interpretation), is
that the "collapses" are psychological, rather than physical
processes. They may be shared events, but are in no way universal. The
history in which alternate outcomes are observed are equally as
"real". Because of this, I prefer the term "Projections", to
distinguish this from the Copenhagen view of the world (universal collapses).
I do feel that communication is difficult because of the need to
simultaneously look at the situation from a 1st person and 3rd person
viewpoint. Simultaneously a bird and a frog perspective.
>
> >
> > Whoa up there! At no point do I admit an absolute objective world in
> > this paper. If you peruse my postings on this list, you will find I
> > believe the opposite. I consider the Multiverse to be an objective
> > object, however it is not in my opinion a "world" in the usual sense
> > of the word.
> >
> > Secondly, the collapse happens not "magically to all observers", but
> > rather just to that subset of observers sharing the history including
> > that "collapse".
> >
> OK, point well taken. I suggest you clarify your post at
> http://parallel.hpc.unsw.edu.au/rks/pubs.html. I think that it definitely
> conveys (to me) an unintended message. Maybe do a cut and paste into your
> site of your second paragraph: "Secondly .... "collapse.""
>
> Otherwise we agree a lot on the evolution process of the universe. In general
> your whole site looks terrific. Great job!
>
> George
>
>
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Dr. Russell Standish Director
High Performance Computing Support Unit, Phone 9385 6967
UNSW SYDNEY 2052 Fax 9385 6965
Australia R.Standish.domain.name.hidden
Room 2075, Red Centre
http://parallel.hpc.unsw.edu.au/rks
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Received on Sun May 21 2000 - 21:57:35 PDT