Diagrams and non-monotonicity in puzzles

Abstract

Liar puzzles have been popularized by Raymond Smullyan in several books. This paper presents a logical and diagrammatic examination of such puzzles in terms of a epistemic truth values. Also, non-monotonic reasoning may occur as new information is learned about a puzzle. This paper presents a way to think about such non-monotonic reasoning which does not involve the use of a non-monotonic logic but instead utilizes context shifts among static logics. The information coming from the presented diagrams is timeless, it is a monotonic back-bone of the whole non-monotonic knowledge.