[ExI] Many Worlds (was: A Simulation Argument)

[Lee Corbin]

Vladimir writes

>> >> of the wave function. But from your point of view, you have a 1/2
>> >> chance of observing that the coin comes up heads or tails.
>>
>> Well, that what it *feels* like, but the truth is that you have a 100%
>> chance of seeing heads, and a 100% chance of seeing tails.
> 
> Chance is a property of (or tool for) your assessment of situation.

That sounds like a subjective or personal 1st-person type of
usage.  I go for the objective usage, any time that I can get
away with distinguishing between the two.

> Before the toss, you don't know the outcome, so chance is 50%. After
> the toss, you know the outcome, so chance is either 0% or 100%,
> depending on it.

What's wrong with that, in my opinion, is that it leads to the fallacious
deduction that "something didn't happen to me".  The truth is that it
*did* happen to you, it's just that the place where you are forming
memories of it having happened are in the other branch.

True, we are not accustomed to this, to put it mildly.  Heretofore
in human history to be experiencing something is to be making
memories of it;  but now, (either with physical duplicates or
with the multiverse), something may be happening to you at
one place without you (at another place) having a clue.

> It's an equivalent interpretation, it doesn't change
> semantics of probabilities. If you can directly observe terminal
> outcomes and select traces leading to them, you can be sure of all
> pieces of information along the way, but not so for a frog.

The frogs ought to get eaten by the birds, so that only 
sensible (in my opinion) statements are made.

>> Yes, I guess so, but saying that they aren't separate may be going
>> a bit far:  we usually say that branches are separate when they
>> can no longer interfere (and hence merge).
> 
> OK, in this sense they are separate, but they still contain common
> substructures, and thus can be said to have 'points of contact'.

I suppose so.

> Elements of these common substructures interact (and these
> interactions are equivalent to being cross-world interactions).
> 
> But likewise elements that are able to interact is a definition of
> world. But definition of world needs an 'anchor' substructure, so that
> it will include those elements that can interact with it. If in above
> example one of common substructures is regarded as an anchor, it will
> select different, but intersecting, collection of elements as its
> world.

Well, I don't know.  That brings up a good question.  Suppose that
we have a certain granite monument, and we set up bifurcating
experiment near it, so that after an "up/down" outcome of the
apparatus, we start to speak about our other selves in the other
world.  Yet the monument could be---if you are right---judged
to be a "point of contact".  Just what does that mean experimentally?
Does it mean that the two branches "share" the monument? Is this
how we should speak?   Well, why not?  After all, the contents of
the monument have not diverged (assuming that the radiating
influences---gravitational for instance---of the experiment haven't
caused differences).

Lee