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

Abstract

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. © 2011 Springer Science+Business Media B.V.