Jacques, I'm really trying to understand your objection to
QTI, but I'm not there yet.
Jacques M Mallah wrote:
>
> On Wed, 2 Jun 1999 GSLevy.domain.name.hidden wrote:
> > And by the way, if the measure was NOT continuous along some branches of the
> > MW, then we could simply ignore those branches since they are irrelevent to
> > immortality, and concern ourselves only with those branches which are
> > relevent where the measure is continuous. (Anthropic reasoning)
>
> What if ALL branches terminate?
I think that no "branches" ever terminate. As I discussed in my
last email, the only relevant consideration for QTI is the present
moment of a conscious being, and the "very next moment", which might
be one Plank time in the future, if you like. As long as there are
some next moments in which my conscious self is alive, I don't need
to worry, my branch has not terminated. Now, I would think that if
any branch ever did completely terminate, then QTI would be in
trouble, but I don't see how that could ever be.
> Note 1: this is perfectly compatible with an ensemble of branches
> which does not terminate even though each individual branch does, if there
> are infinitely many branches.
I don't know what this means. How are "all branches terminating" and
"an ensemble of branches which does not terminate" compatible? What
are you trying to say here?
> Note 2: this is really the situation in QM, if a 'branch' is
> understood as an implementation of a brain computation. If you disagree I
> must ask for a mathematically precise definition of branch.
I tried to give a description of a branch in my last post, but it
was certainly not very precise. I called it "world" there. I think
that in "Many-Worlds", a world is the same as a branch. I also called
it a thread on consciousness. I think I'm understanding, after trying
to get more rigorous about these terms, why so many physicists hate
the term "Many-Worlds".
But again, I'll iterate that as far as QTI is concerned, the only
portion of the branch that is important are the two SAS-observer
moments separated by one "delta-t".
> Note 3: I have not been active recently because I have a lot of
> work to do, and I will have for the next few weeks. To all Qiciders: Do
> not interpret silence on my part as a lack of contempt for your writings.
I'm so relieved!
> Note 4: George, you still owe me an apology re: Bayesian Boxes.
In having read a number of your posts from the archives, let me propose
a description of what I think *might* be why you disagree with QTI, then
you can tell me why I'm an idiot.
Deutsch, in FOR, described an interpretation of MWI wherein worlds
didn't "split", instead, they "differentiated". He gave a diagram
something like this:
Classical MWI, worlds split:
BBBBBBBBBBBBBBBBB
AAAAAAAAAAAAAAA
CCCCCCCCCCCCCCCCC
Deutshian MWI, worlds differentiate:
AAAAAAAAAAAAAAABBBBBBBBBBBBBBBBB
AAAAAAAAAAAAAAACCCCCCCCCCCCCCCCC
Could it be that you are thinking along the lines of Deutschian MWI,
and see each one of us as trapped inside one world, which looks like
infinitely many others? In other words, if you represent my
consciousness as C, according to Deutsch, I could draw my existence
schematically as
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCCCCCCCCCCC
I exist in lots of different worlds, but in each one, I'll only
survive for a limited time. My "measure" is constantly decreasing.
This suggests that I'm in one and only one world, but I just don't
know which. Since I can't jump from one world to another, I'll
inevitably die.
I'm going to assume that this is close to your position, and now
I'll proceed to blow this argument away. If it's not, and instead
I've concocted a straw man, then oh well, at least I'll have had
fun.
First, the interpretation above is in conflict with a computational
approach to consciousness, in which space, time, and indeed, every-
thing we could consider to be a "world" are emergent phenomena. In
comp, we certainly could "jump from one world to another" - in fact,
it is meaningless to say that we are in one world or another, if
*the exact same C* appears in multiple places. So in comp, we can
jump from world to world, and in fact, the Deutschian MWI just does
not fit. So at the instant that one of the lines of C's terminated,
I would jump to another. I'm sure Bruno would have more to say
about this "computational indeterminism".
Note that in the MWI FAQ, Michael Clive Price states that the
"differentiation" model is wrong, that worlds do, in fact, split.
He says that the statistics comes out all wrong with differentiation.
But I haven't studied the math, so I don't know, so I won't rely on
references to authority. If anyone else knows of more info on this
topic, I'd love to hear it.
One might argue that the two interpretations above are isomorphic.
That's kind of the thought I got while reading Tegmark's paper, where
he described us as being firmly embedded within a mathematical
structure, and just not being sure which. Then, in the above
scenario, for any given line of C's, in the next moment, I would
always find myself in one of the lines that continues. To make
this work, you'd have to swallow the FAP (Final Anthropic Principle),
which few people seem willing to do. I'm not sure why; FAP seems
to make sense to me. Considering how *amazingly* unlikely is our
present existence, due to the everyday Anthropic Principle, it
doesn't seem much of a stretch to require that I live forever -
that would be a boundary condition, see.
That's all I can think of for now.
--
Chris Maloney
http://www.chrismaloney.com
"Knowledge is good"
-- Emil Faber
Received on Mon Jun 14 1999 - 19:44:53 PDT