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Stuart_Armstrong comments on Conservation of Expected Evidence - Less Wrong

68 Post author: Eliezer_Yudkowsky 13 August 2007 03:55PM

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Comment author: Stuart_Armstrong 15 August 2007 10:00:31AM 6 points [-]

you can't possibly expect the resulting game plan to shift your beliefs (on average) in a particular direction.

But you can act to change the probability distribution of your future beliefs (just not its mean). That's the entire point of testing a belief. If you have a 50% belief that a ball is under a certain cup, then by lifting the cup, you can be certain than your future belief will be in the set {0%,100%} (with equal probability for 0 and 100, hence the same mean as now).

Getting the right shape of the probability distribution of future belief is the whole skill in testing a hypothesis.