>From: "Bostrom,N (pg)" <N.Bostrom.domain.name.hidden>
>Jacques Mallah wrote (some time back):
>> It has applications in cosmology, evolutionary biology, thermodynamics
>>and the problem of time's arrow, game theoretic problems with imperfect
>>recall, the philosophical evaluation of the many-worlds and many-minds
>>interpretations of quantum mechanics and David Lewis' modal realism, and
>>even for traffic planning.
>
>I would have liked to see some discussion of each
>application. I guess that's for the book.
>
>I suppose so. I haven't at all resolved the target-audience problem yet.
>For instance, you complain about the wordiness, but many philosophers I
>talk to think that it is much to brief in many places. Different cultures;
>hard to satisfy them all. Also remember that few people will have spent as
>much time as you have thinking about these issues prior to reading the
>text.
You could make a dense version and a long one. Some parts of what you
have are redundant or use long words where short ones would be just as
precise.
>Also, you could have included the stuff you and I discussed about how the
>using the MWI prevents some of the counterintuitive consequences (e.g.
>regarding Adam.)
>
>If I remember correctly, I was not convinced that MWI prevents these
>consequences.
I though you were. In
http://www.escribe.com/science/theory/m560.html
you say:
>Yes, you are right that on the MWI, if Adam thinks there is a
>substantial probability that the q.m. chance of a deer appearing is
>substantial, then you wouldn't get the shift that the paper refers
>to. And as you say, Adam could obtain evidence for the hypothesis
>that the q.m chance is substantial from observing his situation.
You also said in that post you weren't sure how to combine the QM
probabilities with the SSA, but in your last post to RS you seemed
reconciled to doing so.
>Even if it did, I don't think it would be very relevant since
>we are concerned with what is a sound methodology, something which, one may
>think, should be independent of specific assumptions about the world. In
>particular, If one is advocating a general principle (such as SSSA-R) then
>a single genuine counterexample, even if it is hypothetical, would suffice
>to refute it or force us to restrict its scope.
I'm not sure what you mean in this context.
>>However, we discover new consequences of SSA that are more
>counterintuitive than the Doomsday argument. Using these results, we
>construct a version of SSA that avoids the paradoxes and does not lead to
>the Doomsday argument but caters to legitimate methodological needs.
>
>Here's the part I really object to. Your SSA was vague (you didn't
>even discuss observer-moments up to that point), but was OK as
>far as it went.
>When you introduced the SSSA, you went off track. Your SSSA
>gives obviously wrong results, such as not leading to the Doomsday
>argument
>On the contrary, SSSA leads to DA just as surely as SSA. It is only when
>going to the relativized version of SSSA, i.e. SSSA-R, that one can avoid
>DA. Funny, btw, that you think that not leading to DA should be considered
>a fault! Most people seem to regard DA as a reductio ad absurdum (which I
>think is unfair, although DA may be rather counterintuitive).
The DA is not counterintuitive as far as I am concerned. It's common
sense.
When I said SSSA I meant SSSAR.
>and in the "god's coin toss" where it gives the wrong Bayesian
>probability for the coin.
>
>Of course, what is the "right" and "wrong" probability is precisely what is
>at stake here.
In the 'coin toss' case, the answer is obvious.
>Nor is there any theoretical justification for not regarding
>all observer-moments to be in the same reference class. (As you
>can tell I am partial to the ASSA.)
>
>The main motivation is that it avoids certain consequences that most people
>regard as highly counterintuitive and unacceptable.
Well, I've already stated that I regard those consequences as obvious
and intuitive. But there's another issue. A motivation is not the same as
a justification. In this, the fact that all OMs should be considered in the
same class is intuitively obvious prior to any consideration of consequences
or shmonsequences.
>You might then ask how I would avoid the Adam-style problem. The answer is
>already somewhere in the paper: if Adam is a freak, we
>don't need to worry much about him. It's in the nature of Bayesian
>probability that for some people the method must backfire.
>
>I do say that, yes, but if we have a nice alternative then this problem can
>become decisive. The thing is not so much that Adam would have been
>mistaken - who cares, except himself? - but rather that we don't seem
>willing to follow the rule that we prescribe for Adam. If we are not
>willing to do that - in all cases where the rule says it should be applied
>- then we don't really accept the rule. That is, we don't really accept the
>unrestricted applicability of SSA. The question then arises, what rule do
>we accept? And I suggest that the answer is SSSA-R.
It's an unfortunate fact that intuition is a double edged sword. It's
our only guide to fundamental issues, but it's also a product of our
specialized experiences, society, etc. and very unreliable when it comes to
guessing complex things.
In this case "our" intuition is based upon the fact that we have never
encountered a situation like Adam's. Darwinian evolution depends upon
repetitive situations, but by definition if Adam is right in thinking he's
not going to reproduce, he wouldn't have reproduced.
I would follow any advice I would give to Adam if I were in his
situation. Of course, thanks to the MWI that's extremely unlikely. (Even
if there are just a lot of regular old alien worlds with life, that would
end Adam's dilemma for the same reason as the MWI.)
>From: "Bostrom,N (pg)" <N.Bostrom.domain.name.hidden>
>Russell Standish wrote:
>
>>I finally had a bit of a chance to glance through Nick's
>thesis. I guess Nick stayed out of the ASSA/RSSA debate for good
>reasons.
>
>Maybe so :-)
>
>>His SSSA introduced SSA over observer moments, so one could
>rightly say that the ASSA and the RSSA are both examples of SSSA.
>Note the SSSA clearly states that the reference class includes all
>observer moments that don't differ by any relevant respect.
I thought that was SSSAR.
>Yes, that's an applicability condition. I imagine that in many real cases,
>maybe some observer-moments will differ in relevant respects, even some
>observer-moments that belong to the same reference class - at least I don't
>yet know any reason to rule out this case. In the context of QM, for
>instance, one may want to assign weights to observer-moments that reflect
>the amplitude of the branches of the universal wave function on which they
>live. Possibly also things like clarity of consciousness etc. should be
>taken into account. It is trivial to bake weightings of observer-moments
>into SSSA-R, but I thought it would just complicate the formula and
>wouldn't really add anything to do so, in the absence of interesting things
>to say about how those weights are to be determined.
>
>I do have some half-baked ideas about how the reference class is to be
>defined, which I didn't include in the thesis. I might try them out here,
>if they look promising after thinking some more about them.
Well, isn't your SSSA-R useless without that?
So how do you come down in the quantum immortality debate? If your
SSSAR is really the same as the RSSA as Russell Standish seemed to say in
his posts to me, that's certainly a counterintuitive consequence of it.
Russell, I know I said my next post would be on your paper, but I've had
other things to do lately. I'm working on it.
- - - - - - -
Jacques Mallah (jackmallah.domain.name.hidden)
Physicist / Many Worlder / Devil's Advocate
"I know what no one else knows" - 'Runaway Train', Soul Asylum
My URL:
http://hammer.prohosting.com/~mathmind/
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Received on Wed Jul 26 2000 - 17:32:05 PDT