Logic is of course a general resource for reasoning at large. But in the first half of the twentieth century, it developed particularity with a view to mathematical applications, and the field of mathematical logic came into being and flourished. In the second half of the century, much the same happened with regard to philosophical applications. Hence philosophical logic. The deliberations of this book cover a varied but interrelated array of key issues in the field. They address the representation of information in linguistic formulation, and modes of cogent demonstration in logic, mathematics, and empirical investigation, as well as the role of logic in philosophical deliberations. Overall, the book seeks to demonstrate and illustrate the utility of logic as a productive resource for rational inquiry at large.

The word apory stems from the Greek aporia, meaning impasse or perplexing difficulty. In Aporetics, Nicholas Rescher defines an apory as a group of individually plausible but collectively incompatible theses. Rescher examines historic, formulaic, and systematic apories and couples these with aporetic theory from other authors to form this original and comprehensive survey. Citing thinkers from the pre-Socratics through Spinoza, Hegel, and Nicolai Hartmann, he builds a framework for coping with the complexities of divergent theses, and shows in detail how aporetic analysis can be applied to a variety of fields including philosophy, mathematics, linguistics, logic, and intellectual history. Rescher's in-depth examination reveals how aporetic inconsistency can be managed through a plausibility analysis that breaks the chain of inconsistency at its weakest link by deploying right-of-way precedence based on considerations of cognitive centrality. Thus while involvement with cognitive conflicts and inconsistencies are pervasive in human thought, aporetic analysis can provide an effective means of damage control.