Re: How does this probability thing work in MWI?

From: Fritz Griffith <>
Date: Tue, 16 Nov 1999 19:59:27 MST

   Now this is where the MWI starts losing its appeal. This 'unequal
reality' is very similar to the Copenhagen 'ghost states' that the MWI was
so successful in avoiding. Is what you say about this unequal reality stuff
just speculation, or is it the actual explanation?
   The only way your unequal reality idea could be the actual explanation is
if reality was defined by, as you say, a third party observer, who could
observe all worlds at the same time. This third party observer would be
quantum mechanics. So you are suggesting that there are different degrees
of reality, and that how real something is is independent of how real we
percieve it to be. Perhaps it is true, but nevertheless it is a very shaky
argument. At the very least, it is a weakness of MWI because of its vague
and confusing statements.
   On the other hand, if you assume that every world is either real or not
real, then you either have the Copenhagen view, or you must accept that
every possible world is real. With the latter view, I have already shown
that order is impossible:

for every split in which we are favored to follow a certain world, there
exists another world of equally real people who assumed they would they
would follow the same path, who instead ended up in the so-called unlikely
world. Because the people in both worlds are equally real, there is no way
to say that we are more likely to follow either path; rather, between this
single-split example, the chance would be 50/50 as to which world we would
end up in. Considering all possible worlds, we are back to the drawing
board - the chance of us actually being in a world that isn't chaotic is
pretty much nonexistant.

So, we have two options: either accept your 'varying degrees of reality'
theory, or go back to the Copenhagen view (or, another option is to consider
the theory in my post, "Why the Wave Function Theory Doesn't Make Sense").

>From: Christopher Maloney <>
>To: everything-list <>, Fritz Griffith
>Subject: Re: How does this probability thing work in MWI?
>Date: Mon, 15 Nov 1999 21:45:06 -0500
>Fritz Griffith wrote:
> >
> > So if MWI is just a mathematical interpretation of QM, then why, in
> > article I read about MWI, does it say that every world is equally real?
> > Could they all be wrong? Also, if every world is not equally real, then
> > wouldn't you basically have the Copenhagen view of QM?
>This is a good point, I think. Perhaps "equally real" is misleading.
>If the measure of two histories is unequal, perhaps one should say
>that they are unequally real -- one is more real than another.
>Actually, this is reminiscent of a discussion I had with Jacques
>Mallah a while back about zombies. I don't believe that such a
>thing as a zombie exists (something that looks and behaves like a
>conscious human, but is not conscious) but I do believe that it is
>probably valid to talk about some people as having a greater measure
>than others -- that is, that some people are more real than others.
>There's a significant difference, I think, between saying that
>something is "less real" and saying that something is "not real".
>Certainly, to those people of low measure, they themselves *feel*
>themselves to be just as real as anyone else. But the measure
>question comes up from a third person perspective (or "bird"
>perspective, or "Archimedes" perspective): how likely is it that
>a self-aware observer will find him/herself to be that person?
>So, to make a long story short, I think confusion can arise from
>the use of the word "real", whether one means it to be a boolean
>on/off state, or something that can be measured by a continuum. If
>one is using it as a boolean, then one would say that alternative
>histories of MWI are all equally real, meaning that they all are
>real, just as ours are. But they are not all equally probable.
> > >From: Christopher Maloney <>
> > >
> > >In this and your previous post, I think you are confusing the MWI with
> > >a *theory*. The MWI is not a theory, it is an *Interpretation* of the
> > >theory of Quantum Mechanics. QM defines the math and therefore the
> > >measure which is manifested by the MWI.
> > >
> > >On the other hand, your questions about measure certainly do apply to
> > >the theory discussed on this list, the All-Universes Hypothesis (AUH).
> > >With the AUH, we need to justify the measure of the alternative worlds,
> > >in order to make predictions for observations. The AUH is not
> > >equivalent to the MWI. It is a sort of super-many-worlds idea, but it
> > >doesn't presuppose quantum mechanics, as MWI does. In fact, ideally
> > >we would be able to derive QM from the AUH. In fact, Russell Standish
> > >purports to have done that in his just pre-released paper, at
> > >
> > >
> > >
>Chris Maloney
>"Donuts are so sweet and tasty."
>-- Homer Simpson

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Received on Tue Nov 16 1999 - 20:07:00 PST

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