Are you tacitly assuming some kind of communication between observers
when you make the claim of a "convergence"? Adsent said communications,
could we show that the convergence would still obtain? Have you ever seen
any discussion of the notion of cyclic or periodic gossiping in Comp Sci?
----- Original Message -----
From: "Tim May" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, July 08, 2002 7:12 PM
Subject: Re: Which universe are we in?
> On Monday, July 8, 2002, at 03:40 PM, Hal Finney wrote:
> > Future uncertainty is familiar to us, but one of the things that the
> > many universe model introduces is past uncertainty. There is a sense
> > in which the past is not unique and determined. My mental state is
> > consistent with many macroscopically distinct pasts.
> I'm not convinced that this is so. Sure, there are many views of past
> events, of history, faulty memories, changing memories, etc.
> However, the "single past" model is quite well-supported by science and
> a kind of "convergence" of knowledge:
> -- we may not have complete knowledge of the past, but experience points
> to the fact that the more different observers learn about the past, the
> more they will (if they are honest) agree on what that past was.
> -- archaeology is a good example: more and more bits and pieces add
> together to "converge" to a unitary past, not to multiple, diverse pasts
> -- this is analogous with measurements in QM: honest observers will
> report the same measurement
> > My brain and my mind hold only a certain amount of information.
> > Vastly more information than that has existed in my past light cone, the
> > history of the universe which has led up to me. My brain is therefore
> > very probably consistent with a great many past histories, each of which
> > will lead to a brain, a mind and a mental state which is
> > indistinguishable
> > from that which I am now experiencing. From my first-person
> > perspective,
> > the past is indeterminate in much the same way as the future is,
> > although
> > to a lesser degree.
> I agree that many possible causal pasts lead up to what you are. The
> placement of grains of sand on a beach in Greece is not going to
> significant affect who you are right now, so this is just one of a vast
> multitude of possible causal pasts which will not affect your currrent
> mental state.
> But this does not mean these possible pasts have equal "actuality." For
> example, two different observers may have carefully photographed the
> patch of beach where the possible variations occurred. The more accurate
> their observations or photographs are, the more closely they will agree
> on what that past was (again, assuming honest observers).
> Nothing in science points to the "many actual pasts" possibility, even
> though I acknowlege your point that "many _possible_ pasts" would lead
> to a indistinguishable equal mental state for you or me.
> In other words, science points to a single actual past. There is, so
> far, no evidence for multiple actual paths.
> (And in the consistent histories picture, we should not be surprised. We
> find ourselves in whichever universe we are in, and we will see one
> actual trajectory through space-time.)
> --Tim May
> (.sig for Everything list background)
> Corralitos, CA. Born in 1951. Retired from Intel in 1986.
> Current main interest: category and topos theory, math, quantum reality,
> Background: physics, Intel, crypto, Cypherpunks