# Re: Doomsday argument & Shooting Room

The Low Willow (phoenix@ugcs.caltech.edu)
Thu, 12 Dec 1996 11:30:19 -0800 (PST)

On Dec 10, 3:33pm, Robin Hanson wrote:

} Consider the case where we are a priori uncertain about the rule used
} to say if the room occupants win. There is a 50/50 chance that they
} win on double sixes, and a 50/50 chance they win on any double. You
} can't tell which rule is being used, even when you go into a room.
} Now what odds should you assign to winning?
}
} The doomsday argument says it should be much nearer to 1/6 than to
} 1/36. Yet if you don't know how many people are in the room with you,
} I think it would have to be nearer to 1/36, the opposite bias! I
} think you do get the bias Leslie expects, however, if you can see how
} many people are in the room with you. (Anyone want to work through
} the details?)

I'm not quite clear as to what analogy is being drawn. It seems to me
that the # of people is relevant only because given the rules, it tells
you what stage of the game you're at, which is all you want to know. If
you're early in the game, you can't tell which rule is being used; if
you're at stage 40, it is more likely that the 1/36 chance is being
used. Back analogy: if there have been many chances for noticeable life
before us, our future odds are bad; if not, we can't tell. But I'm not
sure this is the same as the above problem. It seems more useful,
though.

Merry part,
-xx- Damien R. Sullivan X-) <*> http://www.ugcs.caltech.edu/~phoenix

Be not a beauty proud or vain,
For mortal maid it will be your bane.