Re: Recent paper on MWI (fwd)

From: Jacques M Mallah <jqm1584.domain.name.hidden>
Date: Tue, 4 May 1999 21:10:58 -0400

        The following is from an email sent by Don Page, which he gave me
permission to post to this list. He realizes that quantum immortality is
wrong, and that finding oneself to be old or to have survived suicide
attempts would *not* be evidence for the MWI any more than for a one world
interpretation, due to the low measure. I don't think he ever believed in
'quantum immortality' per se, but didn't fully think it through when he
wrote the original paper.
        I hope some people can learn from his objectivity and integrity in
admitting he made a mistake, and follow his example in dismissing 'quantum
immortality'.

---------- Forwarded message ----------
Date: Mon, 3 May 99 16:35:13 -0600
From: Don N Page <don.domain.name.hidden>
To: Jacques M Mallah <jqm1584>
Subject: Re: Recent paper on MWI

Dear Jacques,

        Thanks for your message. Jerry Finkelstein had asked me how the
evidence of one's living to 2100 would be any diferent from the evidence of
getting any other low-measure result, which would occur in MWI. (I suppose the
only difference I see is that one would not be alive to be aware of the
contrary evidence in other worlds.) But this got me to realize that although
the maverick worlds in which one would live to 2100 certainly exist in the MWI,
they would have so low a measure that one experiencing it would be experiencing
a very low typicality observation, which if one counts the typicality as the
likelihood, as I argue one should do in my Sensible Quantum Mechanics papers,
would be evidence agains the MWI just as strong as against the single-history
version.

        So I agree with your criticism. I had been waitng to change the paper
until I got the referee's report back, but then today I got a message saying it
was too long to be sent out to referees, so I shortened it and also replaced it
at LANL, as you saw from my previous message. (I also thanked you for
discussions.)

        On your last comment, about the anthropic principle, I agree that many
have been saying that one should weight by the number of observers (and I cite
several of them in my paper). But I have not seen anywhere published the
simple observation that one does not get this in single-history QM for choosing
between different possible histories. (Of course it does work for different
parts of one history, and I alluded to that in my discussion of the paper of
Martel, Shapiro, and Weinberg.)

        It was interesting that you referred to Smolin on the anthropic
principle. He attacked it on page 205 of his book under the assumption that it
would produce the least amount of life possible, which is what one would get
from a single-history theory in which one just takes the conditional
probability that life exists, without any further weighting by the amount of
life or consciousness. I'll attach a message I sent to him shortly after
writing my paper. He gave only a very short response that did not address the
issues I raised, which may or may not indicate that he did not violently
disagree with what I had written.

        Thanks again for your comments. I'm not sure when I'll have time to
answer your objections to the combining religion with the MWI, and I'm afraid
I've forgotten what the objections were (except for a vague memeory that it had
something to do with the problem of evil, which certainly is a problem with
almost any worldview but hasn't been taken as fatal by most adherents of
religion).

        Best wishes,

        Don
Received on Tue May 04 1999 - 18:12:28 PDT