[extropy-chat] Doomsday argument

Robin Hanson rhanson at gmu.edu
Fri Oct 13 15:50:31 UTC 2006

At 11:12 PM 10/12/2006, Russell Wallace wrote:
>in the article at
>Nick Bostrom says:
>"For instance, it turns out that if there are many extraterrestrial 
>civilizations and you interpret the self-sampling assumption as 
>applying equally to all intelligent beings and not exclusively to 
>humans, then another probability shift occurs that exactly 
>counterbalances and cancels the probability shift that the Doomsday 
>argument implies."
>Nick, if you're reading this, or anyone else who knows the reasoning 
>applied - what's the motive for this statement? It doesn't seem to 
>me to follow.

If there are many aliens out there, then the total number of 
creatures that we could have been in the universe doesn't change much 
from scenarios where our civilization dies fast or lasts long.   So if
you are a random creature among all these creatures, then you are 
more likely to find yourself in our
civilization if our civilization lasts long and has many creatures in 
it.   This is the "other probability shift."

Robin Hanson  rhanson at gmu.edu  http://hanson.gmu.edu
Associate Professor of Economics, George Mason University
MSN 1D3, Carow Hall, Fairfax VA 22030-4444
703-993-2326  FAX: 703-993-2323 

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