The concept of thetic validity (validity of theses) is the central point of the present pragmatic and dialectical approach. Validity should be seen as the primary aim of argumentation. It is located between mere opinion and true knowledge. An extensive discussion of the definition of thetic validity leads to the criterion of the "absence of open objections." Verdicts of validity are relative to the states of argumentation that have been achieved and refer to an "open forum of arguments." The concept of thetic validity is discussed with regard to universalism, relativism, and pluralism, in contrast with the ideas of Habermas, Peirce, Perelman, and others.