Stathis Papaioannou wrote:
Jesse Mazer wrote:
If you impose the condition I discussed earlier that absolute
probabilities don't change over time, or in terms of my analogy, that the
water levels in each tank don't change because the total inflow rate to
each tank always matches the total outflow rate, then I don't think it's
possible to make sense of the notion that the observer-moments in that
torture-free minute would have 10^100 times greater absolute measure. If
there's 10^100 times more water in the tanks corresponding to OMs during
that minute, where does all this water go after the tank corresponding to
the last OM in this minute, and where is it flowing in from to the tank
corresponding to the first OM in this minute?
As I understood your model, the tanks have constant volume over time
(because net inflow matches net outflow), but you never said they all had
the same volume. If they did, every OM would have the same absolute
measure, so why bother with the idea of absolute measure at all?
No, I don't think they don't all have to have the same volume, but I thought
you were assuming that the ASSA would force us to conclude there's a 10^100
greater chance of finding ourselves as an OM during this minute, an idea
that would only be true if the OMs during that minute *did* have the same
absolute probability/water volume as OMs at other times. It's true that it's
possible to make this example work in terms of the water model if you have
each tank during that minute contain only 1/10^100 the amount of water
that's in tanks before that minute, but in that case your absolute
probability of experiencing an OM in that minute is no higher than at any
other time. So if my interpretation of your argument is right, I think
you're arguing against a strawman version of the ASSA here.
It appears that we both believe that any individual's consciousness will
continue indefinitely, or, as you say in a later post in the current
thread, "death only exists from a third person perspective". However, I
don't really understand the mechanism whereby you believe this will happen.
Perhaps you could tell me where we differ:
My understanding of observer moments is that, unlike the water molecules in
your tanks, they are *always* created and destroyed. The observer's
experience of continuity of consciousness over time results from the
stringing together of OM's which are related in the following way: at a
particular OM in an observer's stream of consciousness, the "next moment",
or successor OM, can be any OM which identifies itself with that observer,
shares the observer's memories up to that point, and fits in as a
continuation of the previous OM's thoughts. (These criteria are necessarily
somewhat loose, accounting for situations such as waking up with retrograde
amnesia after a head injury.)
If you want to have an objective notion of continuity of consciousness and
conditional probabilities, then it can't just be a matter of us subjectively
evaluating how much one observer-moment's memories seem to match the
experiences and memories of an earlier one. Instead, you'd need some sort of
theory of consciousness to give you a well-defined, objective procedure for
deciding this--this is what I've been calling the "similarity function". If
we assume such a thing exists, there are two ways we could think of the
"water molecules". One is to say they represent "observers" who persist
indefinitely, while "observer-moments" just represent what these observers
*experience* at any given moment, not what they are. These observers would
have no qualities of their own beyond what they are experiencing at a given
moment, a bit like the "pure witnessing consciousness" thought to be our
true self in certain eastern philosophies. If this seems too close to the
dualistic idea of a "soul", another option is just to say the water
molecules represent a convenient way to think about conditional and absolute
probabilities in frequentist terms, since it's generally more intuitive to
think about any kind of probability in a frequentist way (rather than, say,
a Bayesian way or a decision-theory way). So in this case the water
molecules would just be a sort of intuition-pump, they wouldn't have any
deeper significance.
Death (from the first person perspective) can be defined as occuring when
there is no successor OM, anywhere or ever. As long as there remains even
one successor OM, be it in another Galaxy, a parallel universe, or
whatever, the stream of consciousness will continue indefinitely. In the
multiverse (or larger mathematical structure containing the multiverse),
there will always be a successor OM; hence, the quantum immortality idea.
You may agree with at least some of the above, but it looks like you may
have a problem with my 10^100 copies, which I propose are created, live for
a minute, then are destroyed. Didn't I just say death can't happen from a
first person perspective? Going by the definition of death above, if the
copies are to really die, there would have to be no successor OM anywhere
or ever (which in this case means the self contained model universe of the
thought experiment). But clearly, there *is* a successor OM. As the end of
the minute approaches, the copies know that the torture is going to start
again. The fact that there is a mismatch between the number of
instantiations during the minute and after (10^100 -> 10) doesn't make any
difference. This is what the purpose of the thought experiment was: to show
that the absolute measure, which is proportional to the number of
instantiations of a given OM, cannot make any first person difference.
But again, if you assume the particular constraint on the *relationship*
between absolute and conditional measure I suggested--the "water inflow
equals water outflow" condition--then it doesn't seem possible for the
combined absolute measure of all OMs during that minute (the total amount of
water in all the tanks corresponding to OMs in that minute) to be larger
than the combined absolute measure of all OMs during the minute before or
after.
Also, let me suggest another way absolute measure makes a difference from a
first-person perspective. Even if I take QTI for granted, I still can have
questions about what my most likely future experiences are going to be,
since I don't know exactly how the conditional probability function works.
In particular, I don't know if in the distant future I will still remember
most of the details of my current life and everything beyond, so that I will
consciously perceive myself to be 10 million years old at some point, or if
I will experience a sort of "immortality with amnesia" where I will
repeatedly perceive myself as being fairly young (I described some ways this
could work in the last paragraph of my post at
http://www.escribe.com/science/theory/m6813.html ). But now if I use the
ASSA, assuming that my current observer-moment is randomly sampled from the
set of all observer-moments, weighted by their absolute probability, then
observing that my age is only 28, I should consider "immortality with
amnesia" much more likely, because if it wasn't the vast majority of the
"water" would be found in observer-moments which perceive themselves to be
Very Old (say, over 1 million years old). Note that this conclusion only
works if you assume the amount of water in each tank stays constant--if the
amount of water in different tanks could change as some sort of cosmic time
parameter moved forward, then it might be that young OMs would be favored by
the ASSA at earlier values of the cosmic time parameter, while old OMs would
be favored by the ASSA at later values of the cosmic time parameter, so I
could no longer use the fact that I find myself to be only a few decades old
to conclude that the conditional probabilities are unlikely to allow me to
continually experience OMs that perceive themselves as being older and
older.
Jesse
