# Re: Request for a glossary of acronyms

From: Jesse Mazer <lasermazer.domain.name.hidden>
Date: Tue, 03 Feb 2004 20:17:25 -0500

Bruno Marchal wrote:
>has been quite useful.
>This does not mean I am totally convince because ASSA raises the
>problem of the basic frame: I don't think there is any sense to compare
>the probability of "being a human" or "being a bacteria" ..., but your
>"RSSA use of ASSA" does not *necessarily* give a meaning to such
>strong form of absolute Self Sampling Assumption, or does it?

No, I don't think it's *necessary* to think that way. Nick Bostrom gives a
good example of the use something like the "absolute self-sampling
assumption" in the FAQ of anthropic-principle.com, where two "batches" of
humans would be created, the first batch containing 3 members of one sex,
the second batch containing 5000 members of the opposite sex. If I know I am
the outcome of this experiment but I don't know which of the two batches I
am a part of, I can see that I am a male, and use Bostrom's version of the
self-sampling assumption to conclude there's a 5000:3 probability that the
larger batch is male (assuming the prior probability of either batch being
male was 50:50). One way to look at this is that if the larger batch is
male, "I" have a 5000/5003 chance of being male and a 3/5003 chance of of
being female--but presumably since you don't think it makes sense to talk
about the "probability" of being a bacteria vs. a human, you also wouldn't
think it makes sense to talk about the "probability" of being a male vs.
being a female. So, another way to think of this would just be as a sort of
abstract mathematical assumption you must make in order to calculate the
conditional probability that, when I go and ask the creators of the
experiment whether the larger batch is male or female, I will have the
experience of hearing them tell me it was male. This mathematical assumption
tells you to reason *as if* you were randomly sampled from all humans in the
experiment, but it's not strictly necessary to attach any metaphysical
significance to this assumption, it can just be considered as a step in the
calculation of probabilities that I will later learn various things about my
place in the universe.

In a similar way, one could accept both an absolute probability distribution
on observer-moments and a conditional probability distribution from each
observer-moment to any other, but one could view the absolute probability
distribution as just a sort of abstract step in the calculation of
conditional probabilities. For example, consider the two-step duplication
experiment again. Say we have an observer A who will later be copied,
resulting in two diverging observers B and C. A little later, C will be
copied again four times, while B will be left alone, so the end result will
be five observers, B, C1, C2, C3, and C4, who all remember being A in the
past. Assuming the probable future of these 5 is about the same, each one
would be likely to have about the same absolute probability. But according
to the Google-like process of assigning absolute probability I mentioned
earlier, this means that later observer-moments of C1, C2, C3 and C4 will
together "reinforce" the first observer-moment of C immediately after the
split more than later observer-moments of B will reinforce the first
observer-moment of B immediately after the split, so the first
observer-moment of C will be assigned a higher absolute probability than
that of B. This in turn means that A should expect a higher conditional
probability of becoming C than B. So again, you can say that this final
the consideration of the absolute probability of all those future
observer-moments was just a step in getting this answer, and that absolute
probabilites have no meaning apart from their role in calculating
conditional probabilities. I can't think of a way to justify the conclusion
that A is more likely to experiencing becoming C in this situation without
introducing a step like this, though.

Personally, I would prefer to assign a deeper significance to the notion of
absolute probability, since for me the fact that I find myself to be a human
rather than one of the vastly more numerous but less intelligent other
animals seems like an observation that cries out for some kind of
explanation. But I think this is more of a philosophical difference, so that
even if an ultimate TOE was discovered that gave unique absolute and
conditional probabilities to each observer-moment, people could still differ
on the interpretation of those "absolute probabilities".

>I think also that your view on RSSA is not only compatible with
>the sort of approach I have developed, but is coherent with
>"Saibal Mitra" backtracking, which, at first I have taken
>as wishful thinking.

What is the "backtracking" idea you're referring to here?

OK you make me feel COMP could be a little less
>frightening I'm use to think.

Well, if I've spared you some sleepless nights I'm glad! ;)

>Concerning consciousness theory and its use to isolate a similarity
>relation on the computational histories---as seen from some first person
>point of view, I will try to answer asap in a common answer to
>Stephen and Stathis (and you) who asked very related questions.
>Alas I have not really the time now---I would also like to find a way to
>explain
>the consciousness theory without relying too much on mathematical logic,
>but the similarity between 1-histories *has* been derived technically in
>the part
>of the theory which is the most counter-intuitive ... mmh I will try soon
>...

Yes, I definitely hope to understand the details of your theory someday, I
think I will need to learn some more math to really follow it well though.
My current self-study project is to try to learn the basic mathematical
details of quantum computation and the many-worlds interpretation, but after
that maybe I'll try to study up a bit on mathematical logic and recursive
function theory. And even if I do, there's the little problem of my not
knowing French, but I'll cross that bridge when I come to it...

Jesse

_________________________________________________________________
Scope out the new MSN Plus Internet Software — optimizes dial-up to the max!
http://join.msn.com/?pgmarket=en-us&page=byoa/plus&ST=1
Received on Tue Feb 03 2004 - 23:17:12 PST

This archive was generated by hypermail 2.3.0 : Fri Feb 16 2018 - 13:20:09 PST