Surprise Paradox

Joachim Breitner 🌐

July 17, 2016


In 1964, Fitch showed that the paradox of the surprise hanging can be resolved by showing that the judge’s verdict is inconsistent. His formalization builds on Gödel’s coding of provability. In this theory, we reproduce his proof in Isabelle, building on Paulson’s formalisation of Gödel’s incompleteness theorems.


BSD License


Session Surprise_Paradox