Games in Philosophical Logic

Semantic games are an important evaluation method for a wide range of logical languages, and are frequently resorted to when traditional methods do not easily apply. A case in point is a family of independence-friendly (IF) logics which allow regulation over information flow in formulas, and thus perfect information fails in the games associated with such formulas. This mechanism of imperfect information is studied in this paper. It is noted that imperfect information of players often gives rise to the game-theoretic phenomenon of imperfect recall. Furthermore, independence-friendliness in epistemic logic is investigated. We also discuss a couple of misunderstandings that have occurred in the literature concerning IF first-order logics and gametheoretical semantics, related to such issues as intuitionism, constructivism, truth-definitions, mathematical prose, and the status of set theory. By straighten out these misunderstandings, we hope to show the importance of the role semantics ga..