From: David Blenkinsop (blenl@sk.sympatico.ca)
Date: Fri Jun 25 1999 - 16:57:43 MDT
"Eliezer S. Yudkowsky" wrote:
> If going
> into the future doesn't send me into a different timeline, neither will
> going into the past. There is no "temporal ether", no single direction
> of time, and the rules have to be the same in both directions.
> Causality *is* circular.
Hmmm, but there *is* an arrow of time, practically speaking, one that
influences most any machine or process of significant complexity. The
most obvious example might be flowing water -- when was the last time
anyone saw a reverse waterfall, with the bits of water all jumping just
right to flow uphill, for instance? No doubt this has to do with the low
probabilistic chances of things coming together in just that way;
unfortunately, probability and statistics is a subject that has a
special "confusion potential" all its' own! Earlier, on the
"Computability of Consciousness" and "Qualia" threads, I talked about
the proper calculation of statistical things like *entropy* being
dependent on the knowledge of the observer doing the calculating, with
Nature hopefully being predictable, in the sense of not biasing the
statistical outcomes in some really strange or unexpected way from the
point of view of any physically reasonable observers. Apparently, we
have to assume that the universe is not too disordered or too scrambled
to begin with, with at least the potential for some observers or
measuring devices to gather some information without melting down or
something. That way, you get a dynamic arrow of time even if the
underlying forces are symmetrical.
>
> Using the term "causality" to refer to what I would call
> "monodirectional causality" doesn't mean that the laws of physics agree
> with you. Nor does a deliberately narrow definition of "causality" mean
> that all order and causality get tossed out the window if the definition
> turns out to be wrong.
Well, in Many Worlds theory, there apparently has to be a dynamic time
arrow in the sense that events tend to cause alternate timelines to
separate or "decohere" from each other, as time moves forward into the
future. When you think about it, it would be really weird, right, if the
separation went the opposite way, i.e., if we all had alternate pasts,
and were forever digging up authenticated histories of past events that
thoroughly contracted one another? So the use of Many Worlds to get rid
of Grandfather Paradoxes seems consistent with the fact that Niagra
Falls flows downhill?
David Blenkinsop <blenl@sk.sympatico.ca>
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