Volume 13, 2008
Logic and Philosophy of Logic
Logic and the Surprise Exam Paradox
In this paper, I analyze the "surprise exam paradox". I think that the paradox can be avoided and I am going to focus on three points: 1) A conflict arises between reasoning and the confidence in the person that makes the original statement. If we examine the situation by reasoning we conclude that the statement is not going to come true, because we trust the person that states it. However, if it is not possible to happen, it happens, and the person told the truth; 2) There is a disjunction among the days of the week: “or it is the first day or it is the second day or … it is the last day” (or Monday or Tuesday or Wednesday or Thursday or Friday). If I still have not been given the exam by Friday, the only possible conclusion is that the exam will be given on Friday. On Thursday, however, the
situation is completely different; 3) It seems that this paradox is a case of contingent futures, which branching time logics usually solve. The truth-value of the sentences is only relative to the branch that takes place in the end.