 In recent years technical machinery from the epistemic foundations of game theory literature and various logics of conditionals has been employed to represent arguments for cooperation and defection in prisoner's dilemma games between replicas (and for one-boxing and two-boxing in the Newcomb problem). See Bonanno for one example and a discussion of several others. These representations make clear some subtle assumptions about the nature of rationality that underly the arguments. Despite the increasing sophistication of the discussion, however, there remain people committed to each view.