Abstract
Recent development of logic has brought about an interest in the interconnections between logic and game theory. As a result, logical calculi have started to be seen as means of delimitation of certain rules, within the framework of which we then play certain games ('of justification'), represented by statements of the corresponding calculi.
The paper discusses two variants of such 'game-theoretical' approach to logic: Hintikka's game-theoretical semantics of classical logic and Lorenzen's dialogic logic.