The problem vexing the minds of experts is as follows: Sleeping Beauty agrees to participate in an experiment. On Sunday she is given a sleeping pill and falls asleep. One of the experimenters then tosses a coin. If “heads” comes up, the scientists awaken Sleeping Beauty on Monday. Afterward, they administer another sleeping pill. If “tails” comes up, they wake Sleeping Beauty up on Monday, put her back to sleep and wake her up again on Tuesday. Then they give her another sleeping pill. In both cases, they wake her up again on Wednesday, and the experiment ends.
In: 0
[Veritasium did a pretty good video on this](https://www.youtube.com/watch?v=XeSu9fBJ2sI). The problem asks “If you’re Sleeping Beauty, *when they wake you up* what should you say is the probability the coin came up heads?”
– Some people say 1/2 because it’s a fair coin, end of story.
– Other people say 1/3 because you wake up twice in the Tails case and once in the Heads case. Basically *the fact that you’re awake* is evidence in favor of Tails, which should change your answer.
Latest Answers