Dialogical logic
Dialogical logic (German: dialogische Logik, also known as the logic of dialogues) is a pragmatic approach to the semantics of logic developed in the 1950s by Paul Lorenzen and Kuno Lorenz. It models logical reasoning as a dialogue game between two participants—a "Proponent" who asserts and defends a thesis and an "Opponent" who challenges it—using concepts from game theory such as "winning a play" and "winning strategy." In this framework, a formula is considered logically valid if the Proponent has a winning strategy for its defense against all possible challenges.