Re: lost in the many worlds

From: Wei Dai <weidai.domain.name.hidden>
Date: Wed, 28 Jan 1998 18:11:48 -0800

On Wed, Jan 28, 1998 at 03:27:41PM -0800, Hal Finney wrote:
> I think you're right that the amount of data would be very large.
> You'd have to count the information content of each wave function collapse
> since the creation of the universe.

I now think that I was probably wrong about this, but I still don't
understand why. Suppose our administrator takes the universal wave
function (which assuming the Everett Postulate never collapses during
normal evolution), collapses it into a position eigenfunction according to
the familiar probabilistic rules, and then examines the resulting position
eigenfunction, treating it a sort of snapshot. Now if he just picks a
random volume of space to look at, chances are he would see some
unstructured interstellar gas. But with probability of about 2^-L, where L
is the length of a complete uncompressed description of my brain (WDB),
the volume of gas he sees would by coincidence turn out to have the same
positional structure as WDB. If I'm to believe that I'm much more likely
to be currently instantiated as a brain made of organic chemicals rather
than of interstellar gas, it must be that the probability of finding the
organic brain is much higher than 2^-L, which implies that it takes much
less than L bits of information to find a description of WDB in the
universal wave function. However I do not know how to derive this from the
principles of quantum mechanics.
Received on Wed Jan 28 1998 - 18:12:25 PST