Re: another paradox and a solution

From: Wei Dai <>
Date: Thu, 26 Feb 1998 18:21:22 -0800

On Fri, Feb 27, 1998 at 01:33:23AM +0000, Nick Bostrom wrote:
> It might be problematic on the AUH (a lot of things are), but apart
> from that I don't see any problems in the present application. What
> is the specific difficulty you see?

The problem is that nothing a person does can affect the outside view,
which is static.

> There might be many instances of the experimenter after the
> experiment. Whose satisfaction are you talking about? If you are
> talking about average satisfaction among the actual instances of the
> experimenter that will exist after the experiement, and all you care
> about is this average (you don't care at all about how many instances
> are enjoying this satisfaction) then you might indeed get the
> implication that you should play Russian roulette in your thought
> example, but what's so paradoxical about that? It wouldn't mean that
> I would have any reason to play Russian roulette in that situation,
> for I don't think I have the goals that your argument presupposes. I
> care about how many branches I will continue to exist on/how many
> copies there will be of me.

These things are part of the outside view. They will remain the
same no matter what you do, so how does it make sense to have a goal of
changing them?

> That's how you define the probability, yes, but how do you define the
> proposition "I will perceive X."?

I don't know how to define it directly, but its meaning is implicit in the
definition of the probability.

> But your argument, it seems, presupposes that I can't care about how
> many instances there will exist of me. That seems wrong.

Part of my argument is that it doesn't make sense to have goals that refer
to the outside view because the outside view is fixed. But I also showed
(with the first paradox) that Tegmark's definition of probability is not
self-consistent. I think that is the more serious problem, since if we
have a consistent definition of probability that isn't compatible with our
current version of decision theory, we can always modify decision theory
or change our ideas of what is rational.

> Well I think that's problematic. How do we interpret these
> "measures"? I.e. what does it mean to say that a certain instance of
> experience has a certain measure m?

One possible interpretation is that every string has an infinite number of
instances, but some have relatively more instances than others. This is
somewhat analagous to intervals of real numbers between 0 and 1. There are
an infinite number of real numbers in every such interval, but some
intervals have relatively more real numbers than others.
Received on Thu Feb 26 1998 - 18:22:03 PST

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