Re: Fermi Paradox in the news

From: Nick Bostrom (
Date: Wed Oct 25 2000 - 20:37:42 MDT

Mike Lorrey wrote:

> > has more on this and many other
> > related topics.)
>I'm enjoying your thesis immensely, Nick.

Glad to hear that.

>I'm currently in Chapter 2, regarding
>Hackings mistake with the Inverse Gambler's Fallacy as applied to Wheeler type
>universes. I don't notice that you've accounted for the fact that Wheeler
>universes, in depending on being able to collapse again to generate the next
>iteration, exclude the set of possible open ended universes (which our own
>to be),

That's one reason why Wheeler's theory is implausible (although you could
imagine the very last universe in the sequence of bounces would be open and
thus never bounce again). Today there are much more popular multiverse
theories, e.g. versions of Andrei Linde's chaotic inflation.

>universe among the ensemble. However White objects to the supposition that
>one such tuned universe is the one we happen to be in as a result of that
>tossing. Your demolition of this argument in respect to life bearing universes
>due to the IF..THEN..ELSE nature of quantum mechanics is rather good, but
>may or

I'm don't understand you here. My criticism of the White objection to the
argument from fine-tuning to the multiverse hypothesis is that White
operates with an erroneous model of how observational selection effects
work. With a correct model, his argument can be seen to be invalid.
Fine-tuning does provide some evidence for the multiverse hypothesis. But
quantum mechanics does not enter into this argument.

Nick Bostrom
Department of Philosophy
Yale University

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