Sleeping Beauty problem

noun

A kind of puzzle in which whenever an ideally rational epistemic agent is awoken from sleep, it has no memory of whether it has been awoken before. Upon being told that it has been woken once or twice according to the toss of a coin, once if heads and twice if tails, it is asked its degree of belief for the coin having come up heads.

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Meanings

nounSleeping Beauty problem (plural Sleeping Beauty problems)

plural Sleeping Beauty problems

  1. decision theoryA kind of puzzle in which whenever an ideally rational epistemic agent is awoken from sleep, it has no memory of whether it has been awoken before. Upon being told that it has been woken once or twice according to the toss of a coin, once if heads and twice if tails, it is asked its degree of belief for the coin having come up heads.
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APA

Sleeping Beauty problem. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/Sleeping%20Beauty%20problem

MLA

“Sleeping Beauty problem.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/Sleeping%20Beauty%20problem. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “Sleeping Beauty problem,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/Sleeping%20Beauty%20problem.

Source: Sleeping Beauty problem on Wiktionary, CC BY-SA 4.0.