Re: Midpoint of history?
Thu, 21 Nov 96 08:34:54 GMT

Hal Finney summarised the Carter-Leslie Doomsday argument
(about a week ago). He mentioned two problems he had with

1) The reference class is not well-defined. -This objection
I think that John Leslie has successfully answered in The
End of the World. The idea is that you can choose any
reference class you like. If you are interested in Homo
Sapiens Sapiens, then you consider your relative position in
that species; if you are interested in any form of
intelligent life stemming from humans, then that is what you
should look at when you define the alternative scenarios.
(BTW, it is not correct to assume as I think Hal did that it
would follow from the Doomsday argument that we should
expect to live at a moment when there have been roughly as
many humans before us as will come after us: the expectation
value of f=time(population) need not be the anything like a

2) One explanation for why we are where we are would be that
we are being simulated by posthumants who like to watch the
critical part of their history aagain and again. -I don't
think this is very plausible. First, I think it is naive to
suppose that these guys would be very interested in watching
the soap opera with you and me in the titel roles over and
over again, complete with all the details of how we trim our
finger nails or go to the toilet -for Godssake, what sort of
idea do you have of these posthumans! Second, even if they
did found some pleasure in this sick show, it would
presumably be economical for them to have many posthumans
watching the same simulation, wherefore they would still be
in majority over us, and we are back again to the fact that
needed explanation.

I myself am busy trying to write a critique of the Doomsday
argument, which, when it is finished, I would gladly supply
to Hal and anyone else who might be interested.

Nicholas Bostrom