>
> 4. Subjective probabilities can be computed on the basis of the
> Strong SSA, and we get
> P(H, t1) = 1/2
> P(H, t2) = P(H, t3) = 2/3
> If this is the case, then I think we have to throw Tegmark's
> scheme using Bayesian statistics out the window. This option
> has severe metaphysical problems, though, in my opinion. I
> think Hal was saying, in his post, either this option, or
> option 1 above, but I'm not sure.
>
> 5. Subjective probabilities can be computed, and we should expect
> the common-sense results
> P(H, t1) = 1/2
> P(H, t2) = P(H, t3) = 1/2
>
> It's a fair coin, after all, right?
> I think this gets Gilles' and Bruno's vote (and Russell's?)
>
> 6. Subjective probabilities can be computed, and we should expect
> the nonsensical results
> P(H, t1) = 2/3
> P(H, t2) = P(H, t3) = 2/3
>
If the probabilities can be computed, then compute them. I have
computed the probabilities as being 1/2,1/2. If you compute them as
1/3,2/3, then you need to advance a similar computation, and then for
good measure, show me where I erred. Probability calculations are
notorious for their subtleties, so I won't take offence at being shown
wrong. At present, the only argument I can see that gives the
probabilities as 1/3,2/3 is the one based on the strong SSA - (your
point 4) - an assumption that I reject.
A reverse causality type of argument would assume that you would never
enter branches that have no escape routes. I have toyed with this
idea, but reject it - principally because I have yet to see an example
of a branch with no escape route, so in essence it becomes
meaningless, but if there were such brances - my belief in foward
causality is so strong, I would prefer to question quantum
immortality, than to invoke reverse causality as a way of salvaging
QI.
> This is what I believe is probably true. I think that there
> must be a sort of "reverse causality" at work, which would
> increase the measure of the right branch of Jane at time t1
> (the branch that sees heads, but before the copy is made).
>
> This still has Jacques' problem of allowing pseudo-zombies.
> If we switch to Jacques' example and assume two copying events,
> then the Jane on the left branch, at time t1, would have less
> measure than the Jane on the right (note the contrast between
> this result and the previous, where the Janes that were the
> product of the second copying operation were accorded less
> measure).
>
> But I don't see this as a problem. What I'm suggesting is that
> each human alive today has a varying amount of "measure". It's
> incorrect to assume that each person, when they are born, is
> given a single "measure unit". By my scheme, a person with a
> terminal illness with only a few days to live would have a
> very small measure of existence, relative to others.
>
> I can't help wondering, often, why I find myself to be the
> particular human I am. Do you others wonder this? One thought
> I've had (please don't laugh at me too badly) is that the fact
> that I have a pretty poor memory might be significant. If I
> had a better memory, then my measure would be less, because
> fewer universes could have given rise to me. Of course, this
> reasoning probably won't work for you, but that doesn't make it
> any less valid from my perspective, which is the only one I
> have.
>
> I came to believe in this "reverse causality" while pondering
> the QS project I wrote about before. I started to expect that
> things would crop up in my way to prevent my being able to
> complete the project, before it came to fruition. It didn't
> (and it still doesn't) make sense to me that the measure of all
> my branches should be unaffected until the very instant that I
> carry out the experiment. Because if the assumption that I'll
> be alive after the experiment date is correct, then I can expect
> to have memories at that time of somehow having escaped. And
> I should, in general, expect to have a memory of "the most
> likely" escape route, or of one of the most likely ones, if there
> are several that are near-equally likely.
>
> But how can one reconcile that with the concept of continuity of
> consciousness from moment to moment? Only if there is a reverse
> causality at work.
>
> This theory has significant and testable implications. Viz: we
> should expect to find ourselves in a universe that will allow us
> to live forever. I.e. this leads directly to the requirement
> that the FAP is true. Just consider if time t1 and t2 are
> separated by a larger and larger time span. Consider also that
> those branches in which we cease to exist also tend to decrease
> the measure of all the observer-moments in previous subjective
> time.
>
True, although it is a very weak requirement. It certainly does not
imply the existence of an Omega point. That it doesn't contradict the
existence of such a point is also illustrated by the Tiplerian type
argument.
> Basically, the measure of our observer-moments at the next
> instant in subjective time are weighted as the number of continous
> paths from that observer-moment to the "Omega-point". This is
> my crackpot theory. Though it's certainly hard to justify on the
> basis of the SSA on a moment-by-moment basis (the Strong SSA), I
> haven't yet found anything that contradicts it. I know that's
> not good enough, but anyway I find it the most satisfying
> result of the above thought experiment. All the other possibilities
> are problematic.
>
>
>
>
> --
> Chris Maloney
> http://www.chrismaloney.com
>
> "Donuts are so sweet and tasty."
> -- Homer Simpson
>
>
----------------------------------------------------------------------------
Dr. Russell Standish Director
High Performance Computing Support Unit,
University of NSW Phone 9385 6967
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 Aug 15 1999 - 20:14:48 PDT