[ExI] Problems with Platonia again

Lee Corbin lcorbin at rawbw.com
Thu Sep 25 23:07:16 UTC 2008

Stathis writes

> So if the universe suddenly disappeared, does that mean 17 would no
> longer be prime?

Well, I'd say that 17 would no longer exist, it being nothing
more (on my theory I spoke about in the "Unreasonable 
Effectiveness" thread).

> > 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.

Must personal identity get dragged into this? Personal Identity
is very controversial in ways that I think have nothing to do
with physical law---yet I do see below that perhaps Platonia
is to you like Personal Identity is to me.

But on my concept of identity, "I" is a pattern, and it happens
to be present in both places equally. So it's simply not the case
that "my" experiences are one of L1 or L2 but not the other.

> 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).

I've already in essence criticized the first part of your paragraph. I agree
with the second part of that (which you just wrote above).

> 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'.

My next subjective experience, yes. In fact, I believe that
I will have all those experiences, because I am a pattern,
or rather an entire fuzzy set of patterns, of which (in that
set) one point corresponds to my subjective now that
is 100% consistent with what the one writing to you is
thinking, hearing, feeling, and seeing now. I am also
living in Lunar City, which arose because Kennedy was
not elected president, and no anti-business legislation
ensued :-)  , but the me's, there, have only like 90% fidelity
to those of me who are writing this.

But you are forcing me to talk like someone who believes
in Observer Moments and Platonia. Since the *pattern*
is all that matters for me, the strict physics continuity
doesn't matter that much. It sort of washes out. If a meteor
comes in at near light speed and kills either the 2008 me,
or the one that lived back when (who is identical) then
of course for me it's just an unfortunate reduction of runtime.

> 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.

I see what you are saying.

> 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'.

I only object to the form of the language here, not necessarily
to what you are saying. To me, it is not true that "I am twice
as likely to experience" one of these options rather than the
other, since I must experience both (i.e., the LC pattern is
executing in both spacetime locations).

> 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.

You guys (the everything crowd), when you talk about about consciousness
flitting here and there, seem to me to be talking as you would of a soul.

> 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.

Yes. It's of low measure in any reckoning. Consider just our 
Tegmark level one universe Bruno (our very own infinite bubble).
If there was nothing else, and not even an MWI multiverse, 
then the set of Lees would mostly keep typing, and only a
very few would see the dragon. Or even have the phone ring
before I get to the end of this sentence.


> If this explanation fails, then I would take that as evidence in
> favour of a single, finite universe.

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