--- Fritz Griffith <fritzgriffith.domain.name.hidden> wrote:
> >From: Jacques Mallah <jackmallah.domain.name.hidden>
> > > > From: Fritz Griffith
> > > > need to bring up probability?
> >
> > To get retrodictions.
>
> That's nice... now what does retrodictions mean?
It's similar to 'predictions', but it means to
indicate something you already know. For example, if
I know the sky is blue, I can study physics to try to
find out why. The theory of scattering of light from
atmospheric fluctuations will claim that the sky
should be blue. That's a retrodiction.
As I define it a prediction by a theory becomes a
retrodiction of the theory as soon as it is verified,
although most people don't talk that way.
> > > > probability (1st person), but rather that we
> > > > experience everything (3rd person only),
> >
> > I never understood the 1st/3rd person crap, so
> >I don't know what you mean. But I know this:
> >effective probabilities are important, and they
> >have absolutely nothing to do with the crap known
> >as "1st person probabilities".
>
> If you don't understand 1st/3rd person crap, then
> how do you know it has nothing to do with effective
> probability?
That's not what I said. To clarify: that which
has been called by others on this list "1st person
probabilities" is not the same as that which I call
"effective probabilities". That much is clear.
> Probability is the chance that a universe that
> exists in the plentitude (3rd person) will be the
> universe you actually experience (1st person).
If you take out the "nth person" stuff from that
sentence, you could be talking about effective
probability. As I've said many time before (see the
archive), the effective probability of an
observer-moment, or of some set or characteristic of
such, is what you should use in the absence of any
other information as the Bayesian probability that
your observer-moment will fall into the category in
question. (More information about yourself modifies
this as usual for conditional probabilities.) It is
proportional to the measure, which in turn is
proportional to the number of observers with those
characteristics, counting N copies as N observers.
(In Bayesian terms, you give equal weight to the
hypothesises that you are each of the observer-moments
in the multiverse, in the absence of more info.) This
is all for a deterministic multiverse, hence the term
'effective'.
> Well thank you for your little lecture on how
> probability works, but I think you missed my point.
I think your point missed me. Chew on what I said
above, and hopefully you will understand how effective
probabilities work in the MWI. I will not expound on
this topic indefinately, so if you continue to
maintain that effective probabilities are meaningless,
I will (effectively) probably not respond.
=====
- - - - - - -
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/
__________________________________________________
Do You Yahoo!?
Send instant messages & get email alerts with Yahoo! Messenger.
http://im.yahoo.com/
Received on Sun May 14 2000 - 18:24:59 PDT