John Anthony Blair

Premissary relevance is a property of arguments understood as speech act complexes. It is explicable in terms of the idea of a premise's lending support to a conclusion. Premissary relevance is a function of premises belonging to a set which authoritatively warrants an inference to a conclusion. An authoritative inference warrant will have associated with it a conditional proposition which is true— that is to say, which can be justified. The study of the Aristotelian doctrine of topoi or argument schemes may contribute to the task of identifying authoritative warrants

I argue that argumentation is not to be identified with (attempted) rational persuasion, because although rational persuasion appears to consist of arguments, some uses of arguments are not attempts at rational persuasion. However, the use of arguments in argumentative communication to try to persuade is one kind of attempt at rational persuasion. What makes it rational is that its informing ideal is to persuade on the basis of adequate grounds, grounds that make it reasonable and rational to accept the claim at issue.

In this overview article, we first explain what we take informal logic to be, discussing misconceptions and distinguishing our conception of it from competing ones; second, we briefly catalogue recent informal logic research, under 14 headings; third, we suggest four broad areas of problems and questions for future research; fourth, we describe current scholarly resources for informal logic; fifth, we discuss three implications of informal logic for philosophy in particular, and take note ofpractical consequences of a more general sort