A curious epistemic state of affairs

Authors

  • Frank Thomas Sautter Universidade Federal de Santa Maria

DOI:

https://doi.org/10.15448/1984-6746.2016.3.21289

Keywords:

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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Author Biography

Frank Thomas Sautter, Universidade Federal de Santa Maria

Professor Associado do Departamento de Filosofia.

Pesquisador do CNPq.

Especialista em Lógica.

References

BELLOS, A. How to solve Albert, Bernard and Cheryl’s birthday maths problem. 2015a. Disponível em: www.theguardian.com/science/alexs-adventures-innumberland/2015/apr/13/how-to-solve-albert-bernard-and-cheryls-birthday-mathsproblem. Acesso em: 06 jul. 2015.

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.

HINTIKKA, J. Knowledge and Belief: An Introduction to the Logic of the Two Notions. Ithaca: Cornell University, 1962.

MARION, M.; SADRZADEH, M. "Reasoning about knowledge in linear logic: modalities and complexity”. In: RAHMAN, S. et al. (Eds.). Logic, Epistemology, and the Unity of Science. Dordrecht: Springer, 2009. p. 327-350. DOI: https://doi.org/10.1007/978-1-4020-2808-3_17

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Published

2017-01-05

How to Cite

Sautter, F. T. (2017). A curious epistemic state of affairs. Veritas (Porto Alegre), 61(3), 456–465. https://doi.org/10.15448/1984-6746.2016.3.21289

Issue

Vol. 61 No. 3 (2016): Epistemology, Language and Metaphysics

Section

Epistemology, Phenomenology and Metaphysics

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