A curious epistemic state of affairs
DOI:
https://doi.org/10.15448/1984-6746.2016.3.21289Keywords:
Logical Puzzle. Design of Puzzle. Proof of Impossibility. Partial Information. Interactive Knowledge.Abstract
I improve on the well-known Birthday Puzzle with a new version that requires only six possible dates. Then, I prove that there is no simpler version of this puzzle. This version, unlike the original, produces the following curious epistemic state of affairs: we, kibitzers, know that Albert and Bernard know Cheryl’s birthday, but we ourselves do not know her birthday. Finally, I discuss a more sophisticated version of this puzzle.
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References
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BELLOS, A. How to solve it: Cheryl’s birthday puzzle. Part Two: Denise’s revenge. (2015b. Disponível em: www.theguardian.com/science/2015/may/26/how-to-solveit-cheryls-birthday-puzzle-part-two-denises-revenge. Acesso em: 06 jul. 2015.
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