# [extropy-chat] Probability of identity - solution?

Lee Corbin lcorbin at rawbw.com
Fri Oct 13 05:35:00 UTC 2006

```Russell recapitulates nicely:

> (For anyone who hasn't read my earlier post: suppose you're copied
> into 2 copies, A and B, then B is copied into 999, should you subjectively
> expect to have a 1/2 probability of finding "yourself" as A, as intuition and
> causal logic would suggest, or 1/1000, as measure accounting would suggest?)

Earlier I wrote that *probability* doesn't provide a very good way of addressing
these problems. I'll note an exception later, however. Another reason that
probability is inappropriate is that probabilities sum to 1.  In these cases, "your"
experiences sum to 1000, not 1.

What about my objection?  It was (perhaps not well-described) along these
lines:  Suppose that the A/B split occurs after .0001 seconds, and the
subsequent splits to B all occur in the next .0009 seconds.  Then all the
forking is over in a millisecond.  In that case would it not seem peculiar
to suppose that the single copy experiencing A was as representative
of you as the 999?   We must banish the notion that there is a soul and it's being
divided into ever smaller pieces!

The exception I spoke of before, where probability *must* rear its head
is for *planning* purposes.  Suppose that the 999 of you will be copied
into a location several hundred feet under water, and only one of you
copied into a location at STP. Then you should walk around all day long,
even while driving to work and at the theatre, in your scuba gear. I explore
the feelings that one would have while taking such steps in my old story
http://www.leecorbin.com/PitAndDuplicate.html , a link I've posted here
many times.

> I think I may have the solution now.

> Specifically: if you choose to define your reference class by causal logic, then you
> get the causal logic conclusion. If you choose to define your reference class by
> measure accounting, then you get the measure accounting conclusion.

I guess that's one way to solve the problem.

> If you want to know which "really" defines you - then the answer is, you'll "really"
> have died a second from now anyway,

Well, I can't go along with that.  It's really not the case upon the usual
meaning of words, to say that Smith has just died when Smith looks
and sounds just the way he did ten minutes ago. We really are concerned
with *survival*, and so we have to reject philosophical stances that
introduce concepts that wouldn't be useful in any imagined situation.
(At least in any situation I've ever been able to imagine.)

Lee

> because "yourself" then will not be the same entity as "you" now (scare quotes because we're voiding the warranty on the words in
> question, but you get the idea). So decide what you care about, and aim for that. (This meshes nicely with the way the measure
> accounting viewpoint is consistent with morality - it gives the same policy decisions one would get if the 999 B's were randomly
> selected from your fellow humans rather than being copies of you.)

> And this is the kind of explanation one was looking for - in the absence of an undercutting defeater for one viewpoint against the
> other, one would philosophically expect different results to be explained by different premises. I think this one is satisfactory,
> though I'm open to counterarguments.
<

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