Journal of Philosophical Logic

, Volume 41, Issue 2, pp 493–503

Why the Hardest Logic Puzzle Ever Cannot Be Solved in Less than Three Questions


DOI: 10.1007/s10992-011-9181-7

Cite this article as:
Wheeler, G. & Barahona, P. J Philos Logic (2012) 41: 493. doi:10.1007/s10992-011-9181-7


Rabern and Rabern (Analysis 68:105–112 2) and Uzquiano (Analysis 70:39–44 4) have each presented increasingly harder versions of ‘the hardest logic puzzle ever’ (Boolos The Harvard Review of Philosophy 6:62–65 1), and each has provided a two-question solution to his predecessor’s puzzle. But Uzquiano’s puzzle is different from the original and different from Rabern and Rabern’s in at least one important respect: it cannot be solved in less than three questions. In this paper we solve Uzquiano’s puzzle in three questions and show why there is no solution in two. Finally, to cement a tradition, we introduce a puzzle of our own.


BoolosLogic puzzleInformation theory

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.CENTRIA - Centre for Artificial IntelligenceThe New University of LisbonLisbonPortugal