Re: Possible Worlds, Logic, and MWI

From: Tim May <>
Date: Fri, 10 Jan 2003 21:09:21 -0800

On Friday, January 10, 2003, at 08:54 PM, Tim May wrote:

>> Wei suggested that in the context of a many-worlds universe (not just
>> the quantum MWI but even for a broader set of possibilities), you
>> might
>> not make this same decision. You know that when the coin flips, the
>> universe is going to effectively branch and both possibilities are
>> going
>> to be actualized. Let us suppose that in addition to slightly
>> preferring
>> apples to oranges, you have a strong value preference for diversity.
>> You like variety and you dislike having everything the same
>> everywhere.
>> In that case, you might rationally choose to receive an apple on heads
>> but an orange on tails. While this slightly reduces your average
>> pleasure level in terms of tasting the fruit, this could be more than
>> compensated by your increased pleasure at knowing that you are
>> enjoying
>> diverse experiences in the two worlds.

To add something to my last comment, there is a huge difference between
these two situations:

1. Alice believes in the MWI, whether it is true or not.

2. The MWI is true, whether Alice believes in it or not.

I fully accept that Situation 1, where Alice believes in the MWI, can
and likely will alter her choices. She may alter her risk assessment
model, she may change what she believes about religion, and so on.

I think, Hal, that in your language above you are confusing the issue
of Alice's faith in MWI with the actual reality or nonreality of MWI.
Your comments about "You know that when the coin flips" and "knowing
that you are enjoying diverse experiences in the two worlds" are not
statements about what is actually happening but, importantly, about
what Alice _believes_ will happen.

This is paralleled in religion:

"Alice knows that when she prays to Baal, he listens and smites her
enemies. She knows that Baal has prepared a place for her in his party
room in the afterlife. She knows that dying young for Baal will only
take her to Baal that much sooner. She awakens every day with hope and

No doubt that belief alters behavior. But it doesn't make either the
existence of MWI or Baal any more real.

(Understand of course that I am not putting belief in MWI on the same
level as belief in YHWH or Allah or Baal or Yog-Sotteth. But we must be
careful in using language like "You know that your choice does such and

--Tim May
Received on Sat Jan 11 2003 - 00:12:09 PST

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