Re: Proof/insistance of multiverse/plenitude?

From: Chris Simmons <>
Date: Thu, 11 May 2000 21:24:36 +0100 (BST)

On Thu, 11 May 2000, Scott D. Yelich wrote:

> First, let me state that I am not a scientist that deals
> with this stuff -- so please forgive me if I seem
> naive or non-technical... but I have a question:
> Why are some people so adament about a "plenitude" or
> a "multiverse" ... what proof is there that is so
> convincing that the defenders of this faith are
> unwilling to discuss anything else?
> Scott

I don't know about proof, but personally it's down to an intense dislike
of random numbers; more to the point, I think there is absolutely no need
to have any concept of random, just a concept of branching.

The following example should explain what I mean. Consider the following
universe. In the universe, all that happens is that a fair coin is tossed
at time 1,2,3,4,.....

That is, you could imagine this universe being part of our own. You're
sitting there watching, say, some wave function collapse performed over
and over, and each outcome is equally likely. Practically we can't wait
forever, but lets not worry about that for now huh?

Anyway; we can record such a universe a right-infinite sequence of H's and
T's where H denotes a head and T a tail, or *whatever*.
eg you might see

or even:

We can even say things about such sequences; indeed, we'd never expect to
see the sequence HHHHH... going on for ever. Now there's another way of
imagining this universe, in terms of a multiverse, ie a much bigger
universe in which any instance of the smaller universes are just 'pieces'
of the overall structure. The structure looks like this
        H T
    H T H T
  H T H T H T H T
etc... Err I can't draw it very well, but basicaly imagine the multiverse
to consist of a tree; from each node theres a left branch to H and a right
branch to T.

Now we think of time in this universe as doing a depth first search in
this universe;
ie something like
1 (H,T)
2 (H(H,T),T(H,T))
3 (H(H(H,T),T(H,T)),T(H(H,T),T(H,T)))
so asking about probabilities is asking about the relative density of
sequences in the depth-first search. eg saying that we'd expect to see
about as many h's as t's in the long run amounts to noting that most
sequences of H's and T's have this property; their relative density in the
depth first search is quite high. Kinda thing. The beatiful about this
way of doing things is that even though the depth-first-search
'multiverse' is completely deterministic, if you live inside this
multiverse you only ever see *one* of the branches, which makes it look
random. This happens because, since your mind records what's occuring
during this depth first search, you also end up with a depth first search
of your mind experiencing ever possibility. Some consious experiences,
there for (such as seeing a sequence with about as many H's as T's) are
more common - more 'probable', whilst seeing nothing but H's is rare to
say the least.

Did that make any sense?

Actually, any sane person who starts tossing coins and finds nothing but
heads occuring would start to get very worried indeed, and probably stop
tossing the coin and start praying. ;)

Chris Simmons.
Don't bother, the web page is crap ;)
Received on Thu May 11 2000 - 13:32:07 PDT

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