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

[Stathis Papaioannou]

On 17/01/2008, Lee Corbin <lcorbin at rawbw.com> wrote:

> >> Say there are two identical versions of you, A and B, contemplating
> >> a quantum coin toss. Because A and B are identical, there is no way
> >> for you to say that you are one or the other.
>
> And I would further say that it's not the case that you *are* one
> or *are* the other.  You are both.
>
> >> After the coin toss, A sees heads and B sees tails. From a God's eye
> >> view, the two parallel worlds of A and B continue, with different things
> >> happening in each one. This is like the deterministic, unitary evolution
> >> 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.

Yes, the *objective* reality is that both outcomes occur and both A
and B have an equivalent claim to being you. But only an observer
outside the multiverse can see this. For an observer embedded in the
multiverse, it seems that there is only one world with a probabilistic
outcome for the coin toss.

> >> This is like the subjective appearance of a truly random wave
> >> function "collapse". So there is no collapse, no splitting or
> >> duplication, and no truly random (or equivalently, uncaused)
> >> events; but for an observer embedded in the system, it looks
> >> as if there is.
>
> Why do you say that there is no splitting?  Say a GIU (Group of
> Identical Universes, a term Deutsch uses over and over in the book
> "Fabric of Reality") bifurcates into the "heads" and "tails" branches
> you spoke of above.  Why don't you consider this splitting, or have
> I misunderstood?

"Splitting" and even "branching" could imply that some special
physical process, over and above simply having two different outcomes
to a quantum event, occurs to physically separate the worlds. Let's be
clear that these commonly used terms are metaphors.



-- 
Stathis Papaioannou