ABSTRACT
A highly general concept of plausibility can be employed in the rationally critical enterprise of discriminating good arguments from bad. Chapter 3 advances three proposals for argument evaluation. The proposals are keyed to arguments conditioned by different degrees of uncertainty: mild, where the argument’s premises are hedged with point-valued probabilities; moderate, where the premises are hedged with interval probabilities; and severe, where the premises are hedged with nonnumeric plausibilities, such as ‘very likely’ or ‘unconfirmed’. The chapter’s proposals are grounded in both the mathematical concept of probability and the more general concept of plausibility axiomatized in Chapter 2. These proposals share a common approach to argument evaluation that complements established frameworks for evaluating arguments. In fact, this approach can be looked at as a generalization of the truth and validity conditions of the classical criterion for sound argumentation.
