Hi all -- it's been a long time since I've participated in this group.
I've been lurking for a few days, and am very pleased with the quality
of the posts that I've read! It's good to see that this discussion
Some comments below.
Tim May wrote:
> 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 like this concept quite a lot. It's esthetically pleasing -- treating
the past and the future more symmetrically than usual.
> 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:
Do you know that this is so -- that the "single past" is supported to
the exclusion of the "multiple past" concept?
> 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).
Ah, but you missed the point, I think. Even if those grains have been
observed by other humans, they still haven't been observed by *me*. My
present mental state is consistent with lots of different possibilities
with regards to position of the grains of sand, *and* to the observation
or non-observation, *and* to the meta-observation, etc. Think
> 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.
I *think* that this topic is treated in Victor Stenger's "Timeless
Reality". Has anyone read it? I started it, but as often happens, I got
distracted before I finished it.
> In other words, science points to a single actual past. There is, so
> far, no evidence for multiple actual paths.
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