[ExI] Problems with Platonia again

Stathis Papaioannou stathisp at gmail.com
Thu Sep 25 12:50:38 UTC 2008


2008/9/25 Lee Corbin <lcorbin at rawbw.com>:

> In particular, how does a physical law obtain from a Platonia
> viewpoint? Suppose snapshots are all that exists. Let a sequence
> of them be f1, f2, f3, f4, ... that amount to a photon in motion
> which is following a Maxwell equation, conserving momentum
> and so on. But somewhere in the pile of all possible configurations
> of the universe is an f3', which has the photon in some very weird
> place and an f4' so that between them f3' and f4' correspond to
> a photon going the other direction far, far away. Why is f2 somehow
> more tightly coupled to f3 than to f3'?
>
> I.e., how does physical law emerge?

This same problem arises in any multiverse model, including a single
infinite universe. Suppose there are two identical versions of you, L1
and L2, a vast distance apart. Then it isn't possible for you to know
whether your experiences are those of L1 or L2. In another moment, L1
evolves into L1' and L2 evolves into L2', both of which have identical
subjective content. Again, it isn't possible to know which one of
these you are. And given these facts, it isn't possible for you to
meaningfully claim that you now, whether L1' or L2', are the
continuation of L1 or L2, respectively. For if, say, we had the same
situation except L1 and L2' were eliminated, you would have had
exactly the same experiences: first as L2, then as L1' remembering
being L2. (I know you don't like the idea of having your total runtime
halved in this way, but the point is, you wouldn't notice it had been
halved, and this has the same significance as the fact that you
wouldn't notice you had been killed and a copy made elsewhere if you
underwent teleportation).

Extending this idea, suppose there is a third version of you, L3, and
a successor L3', both of which are distinct in subjective content from
L1, L2, L1' and L2', but such that the subjective content of L3'
*could* have followed from L1 or L2. Then if you are currently
experiencing L1, your next experience might be drawn not only from L1'
or L2', but also from L3'. There is no basis for saying that L1' is
"more tightly coupled" to L1 than L2' or L3' are, provided that L3'
has the right sort of subjective content. But we might be able to say
that you are twice as likely to experience L1'/L2' (which we said have
identical subjective content) rather than L3' as successor to L1/2,
since there are twice as many versions of L1'/L2' as of L3'.

The upshot of all this is that in a multiverse, your consciousness can
flit about passing through all physical copies with the right sort of
subjective content. The only thing that stops you experiencing
extremely weird shifts from moment to moment must be that such shifts
are of very low measure: there just aren't that many versions of you
in the multiverse where you observe a fire-breathing dragon where
previously your memory tells you there was a keyboard. If this
explanation fails, then I would take that as evidence in favour of a
single, finite universe.


-- 
Stathis Papaioannou



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