When they actually brush up against the real world, whether or not they're rational becomes obvious. Either they win or they don't. The nail's nailed, or it's not.
Whether they're rational or not becomes determinable with moderate certainty.
If they happen to get hit by a meteorite while walking on the sidewalk, they lose, but were not irrational for walking on the sidewalk. If they happen to win the lottery, they win, but were (let's stipulate it is a normal scenario) irrational for playing.
One should evaluate choices by their probable, rather than actual, outcomes. In practice this is very difficult and actual outcomes are a good proxy.
In practice, you don't win the lottery.
I am beginning to suspect that novice rationalists should actually go buy a scratch ticket — do the math, then try it anyway, actually notice that you don't win, that it was a dumb idea (or at least, a money-losing idea) to play, and that this is what a one-in-a-million chance feels like: it feels like losing a buck, 999999 times out of a million.
Today's post, Two Cult Koans was originally published on 21 December 2007. A summary (taken from the LW wiki):
Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Politics and Awful Art, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.
Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.