FOUNDATIONS OF THE THEORY OF ARGUMENTATION

This study investigated the question, what are the logical foundations of the theory of argumentation? It studied a variety of theoretical literature published in the fields of speech communication and philosophy. These materials were analyzed with the methods of theoretical criticism.; The inadequacy of traditional deductive logic for the theory of argumentation is well recognized. The principal reason for which traditional deductive logic is inadequate is the assumption that the meaning of a proposition can be stipulated only by stating the conditions under which it is true and that logic must be truth-functional. Careful examination of rhetorical discourse shows that many rhetorical arguments are not truth-functional.; Although most scholars today have moved away from the study of logically-oriented theories of argumentation, the dialectical and rhetorical perspectives do not serve the purposes of logic. Instead, an improved theory of logic holds that meanings can often be stipulated by stating the conditions under which a proposition is justified. There is a logical connection between a claim and the evidence that justifies it. The logical types of evidence and claims can be organized in a way much like that implied in Toulmin's Uses of Argument. Most sound arguments are prima facie acceptable, but not truth-functionally valid by the standards of conventional logic.