Abstract

These two small works are a good supplement to Rescher’s recent trilogy. Whereas the systems-theoretic approach is employed in Methodological Pragmatism in dealing with the problem of the legitimation of claims to factual knowledge or cognitive rationality, Dialectics deals with the argumentation aspect of thesis-introduction rather than the logical aspect of thesis-derivation. Although some key notions such as the idea of burden of proof and presumption have been stated in the former work, what is offered here is a systematic discussion of a disputational model of inquiry. The principal aims are "to exhibit the sociocommunal roots of the foundations of rationality, to provide an instrument for the critique of scepticism implicit in the cognitive solipsism of the Cartesian approach, and to illuminate the communal and controversy-oriented aspects of rational argumentation and inquiry—scientific inquiry in particular." Again, Rescher limits his discussion to "the probative mechanism in the factual domain." This book, if it were not for its price, should be a good supplement to a course in "informal" logic which focuses on argumentation rather than on mere evaluation of arguments. Plausible Reasoning provides the mechanism for evaluation of plausibility claims as distinct from probabilistic ones. The basic differences between these two types of claims are clearly discussed. "Plausibility is essentially a classificatory concept which ranks theses in terms of the standing and solidity of their cognitive basis. Plausibility grades theses by an external or extrinsic standard of the hierarchical nature of their supporting bases. It classifies propositions by the status of the evidential sources or validating principles that vouch for them. Probability weighs alternatives and evaluates theses by this relative contentual weight of the supporting considerations."—A.S.C.