Argumentation occurs through and as communicative activity. Communication (and therefore argumentation) is organized by pragmatic principles of expression and interpretation. Grice’s (1975) theory of conversational implicature provides a model for how people use rational principles to manage the ways in which they reason to representations of arguments, and not just reason from those representations. These principles are systematic biases that make possible reasonable decision-making and intersubjective understandings in the first place; but they also make possible all manner of errors and abuses. Much of what is problematic in argumentation involves the ways in which the pragmatic principles of communication are exploited and the difficult...