Frans Hendrik van Eemeren (born 7 April 1946, Helmond) is a Dutch scholar, professor in the Department of Speech Communication, Argumentation Theory and Rhetoric at the University of Amsterdam. He is noted for his Pragma-dialectics theory, an argumentation theory which he developed with Rob Grootendorst from the early 1980s onwards. He has published numerous books and papers, including Strategic Maneuvering in Argumentative Discourse.
Informal logic encompasses the principles of logic and logical thought outside of a formal setting (characterized by the usage of particular statements). However, the precise definition of "informal logic" is a matter of some dispute. Ralph H. Johnson and J. Anthony Blair define informal logic as "a branch of logic whose task is to develop non-formal standards, criteria, procedures for the analysis, interpretation, evaluation, criticism and construction of argumentation." This definition reflects what had been implicit in their practice and what others were doing in their informal logic texts.
Informal logic is associated with informal fallacies, critical thinking, the thinking skills movement and the interdisciplinary inquiry known as argumentation theory. Frans H. van Eemeren writes that the label "informal logic" covers a "collection of normative approaches to the study of reasoning in ordinary language that remain closer to the practice of argumentation than formal logic."
Pragma-dialectics (also known as the pragma-dialectical theory) is a program in argumentation theory developed since the late 1970s by Dutch scholars Frans H. van Eemeren and Rob Grootendorst at the University of Amsterdam. It conceives argumentation as a form of goal-directed communicative activity aimed at the reasonable resolution of differences of opinion by means of a critical discussion. Combining a pragmatic interest in how argumentative discourse is actually used with a dialectical interest in how it ought to proceed, pragma-dialectics studies argumentation as a complex speech act that occurs in natural language use and serves specific communicative purposes.
The theory is both descriptive and normative. It offers tools for reconstructing ordinary argumentative exchanges in terms of an ideal model of a critical discussion and uses that model to evaluate whether a discourse contributes to resolving a disagreement in a reasonable way. Central to pragma-dialectics is a four-stage model of critical discussion (confrontation, opening, argumentation and concluding) and a set of ten discussion rules that parties should observe; systematic violations of these rules are treated as fallacies. The approach integrates insights from critical rationalism, formal dialectics, speech act theory, Gricean language philosophy and discourse analysis, operationalized through meta-theoretical principles such as functionalization, socialization, externalization and dialectification.