Re: all of me or one of me

From: Gilles HENRI <>
Date: Tue, 6 Apr 1999 09:55:25 +0200

WD wrote:

>Given the MWI or one of the "everything" theories we've discussed, the
>universe must contain multiple observers who have exactly the same
>memories and experiences as you do. Should you identify with all of them,
>or should you think, "I am one of these people, but I don't know which"?
>I think the following thought experiment shows the latter is more
>appropriate. Suppose you are one of two people in a prisoner's dilemma
>type game, where if you push button A both players will get 4 dollars, but
>if you push button B you will get 5 dollars and the other player will get
>nothing. The twist is that both players are given temporary amnesia and
>are put into identical rooms so you don't know what your identity is.
>If you identify with both players, then you should press A. However I
>think most people under the circumstances will press B. This implies
>people must condition their goals (utility functions) on their identities.
>That is, they must think like this:
>There is equal probability that I am player 1 or player 2. If I am player
>1, then I want to maximize player 1's payoff. If I am player 2, then I
>want to maximize player 2's payoff. If I press A, my expected utility is
>.5*4+.5*4=4 (plus 4 if the other player pushes A). If I press B, my
>expected utility is .5*5+.5*5=5 (plus 4 if the other player pushes A).
>Therefore I should press B.

>I don't think it is possible to obtain this result if each player has only
>one unconditional utility function defined over states of the universe.
>This seems to imply that traditional decision theory is incomplete.

I think it is a weird way of reasoning. The "copies" of you in MWI are not
in the same observable Universe, so you cannot interact with them or share
anything. Experiment like that you describe cannot happen. In our
observable Universe, you are sure to be different from other people, even
if you are amnesic. So you have a 100% probability not to be the other guy!
To know "who we are" is a social definition. The fact that you remember
your past is irrelevant for your choice. So the game is the same as with
any other guy, and it is indeed related to superrationality.
It is not obvious that all people would choose B. In the actual all day
life, we often make choices that are not the most interesting for us
immediately, for example in respecting laws. Human people have a capacity
of identification to other people (that produces also altruism, compassion
and so on...) that allow social rules to exist, and that avoid a pure
selfish behaviour. This can produce a "delayed reward", like in this game.
The decision theory could well choose the "general interest" as the
function to maximise...

Received on Tue Apr 06 1999 - 00:57:06 PDT

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