 To return for a moment to Lorenzen: he failed to distinguish between different stances that a person might take in an argument: stating, assuming, conceding, querying, attacking, committing oneself. Whether it is really possible to define all these notions without presupposing some logic is a moot point. But never mind that; a refinement of Lorenzen’s games along these lines could serve as an approach to informal logic, and especially to the research that aims to systematise the possible structures of sound informal argument. On this front see Walton and Krabbe 1995. The papers in Bench-Capon and Dunne 2007 are also relevant. 