ABSTRACT
This chapter introduces concepts from deontic logic as means of designating certain assertions as normative. Formal logic divides into various areas. One of them is deontic logic, the logic of norms. Deontic logic sets forth relationships linking such concepts as "obligation," "prohibition" and "permission." The concepts of obligation and permission will be of particular interest when theorists turn to arguments of a normative character. The relationships which can be drawn between these concepts will recall the kinds of relationships set forth by Hohfeld. Theorists will accept that a party might adopt two conflicting positions in order to adduce distinct arguments, e.g., in order to argue in the alternative, but not to express any one argument. Relationships of equivalence and necessary conditional relationships can be introduced as steps in proofs in order to derive arguments. As a justifying step, a relationship of equivalence can be marked "RE", and a necessary conditional relationship can be marked "NCR".
