In search for criteria of relevance for argumentation theory

Argumentation theory studies the process of arguing, which is seen as rational action where claims are made and justified. There is a tradition centred around classical logic, in which the logical theory is extended to be applicable to model inferences in argumentation. In this work the logical approach is viewed with the eye on it’s ability to evaluate arguments against logical validity, and it is noted that validity is not sufficient, the problem being on relevance. During the last few decades argumentation studies as well as novell approaches to logic have proliferated. One of the most influencial argumentation theories, which is presented in some detail, is the Pragma-Dialectical theory, which despite of it’s many merits lacks satisfactory criteria for evaluating relevance. Important attempts to capture the concept of relevance are looked at in the field of logic, but not all are seen satisfactory. A theory by Gerhardt Schurz is seen as most promising and it’s insights are applied to Pragma-Dialectical theory. Some formal properties of relevance are discussed and the use of Schurzian Relevant deduction is shown to be promising by applying it to Gettier’s problem, which turns out to be resting on irrelevant argument. As a consequence, theory of justification and with it, the classical definition of knowledge is can be slightly revised.