Re: ASSA vs. RSSA and the no cul-de-sac conjecture was (AB continuity)

From: Bruno Marchal <>
Date: Thu, 12 Feb 2009 16:48:22 +0100

Excellent post Johnatan.

Of course those who know a bit of AUDA (which I have already explained
on the list) know that from the third person self-reference views we
have cul-de-sac everywhere ("we die all the times", cf the
"Papaioannou multiverses"), and this is what forces us, when we want a
theory of observation (which by UDA is a probability or credibilty
calculus) to define the probabilities by imposing the absence of cul-
de-sac. This is *the* motivation for the new box Bp & Dt. Dt, by
Kripke semantics, is equivalent to imposing the absence of cul-de-sac.
Yet, by incompleteness Dt is not provable by the machine, and after we
make the addition of the "non-cul-de-sac" principle (Dt), we loose the
Kripke semantics. But this is a good news, given that we will have to
manage (plausibly) continua of "next observer momen or historiest".

Apology for those who have not follow the (many) old modal posts, but
we will soon or later come back to this. Read Boolos book (and
mathematical logic books).


On 12 Feb 2009, at 00:09, Johnathan Corgan wrote:

> While I wasn't around for the original ASSA vs. RSSA arguments on the
> list here, and I'm sure I'm risking a rehash of things back then, the
> recent traffic over "adult vs. child" and "AB continuity" seems to
> revolve around this anyway.
> It seems intuitively obvious to me that from a 1st-person
> perspective, I
> have to treat successor observer moments with a /conditional/
> probability. My next observer moment I face would be selected from
> among only those where a), I am conscious, and b) those with
> memories of
> this one, or more generally, with a causal thread of continuity with
> this one (unitary evolution of SW). So my subjective expectation
> would
> then be the absolute probability of those occurring conditioned on, or
> given, that the one I'm in now has already occurred.
> It is an open question (to me at least) whether there are any observer
> moments without successors, i.e., where the amplitude of the SW goes
> to
> zero. If it does not, then this implies that the always branching
> tree
> of observer moments has no leaf nodes--rather, it becomes an ever
> finer
> filigree of lines, but any particular point will always have a
> downstream set of forks. This is the essence of the no cul-de-sac
> conjecture, and the crux of the quantum theory of immortality.
> If the above is true, then the absolute measure of an observer moment
> becomes irrelevant; it's clear that as one traces through a particular
> branch it would always be dramatically decreasing anyway. But the
> relative measure of my next observer moment to this one becomes the
> thing that drives my expectations of what I am "likely" to experience.
> Indeed, some version of me experiences all of them, but each split
> copy
> of me can only say to himself, "what I am experiencing now was likely
> (or unlikely) given where I was a moment ago."
> Johnathan Corgan
> >

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Received on Thu Feb 12 2009 - 10:48:35 PST

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