Maintaining obligations on stative expressions in a deontic action logic

Abstract

We consider the logical representation of obligations on stative expressions such as The yard must be clean in the context of legal contract formation, execution, and monitoring (cf. Wyner ([28])). In a contract, the expression may understood as an obligation to maintain a property. We use a Deontic Action Logic to represent obligations over the course of time (Khosla and Maibaum ([13]) and Meyer ([17])). Our analysis is in contrast to d'Altan, Meyer, and Wieringa ([6]), who reduce deontic operators to an Alethic Logic plus a violation proposition (Anderson and Moore ([1])), which has no temporal component. In addition, they use a Deontic Action Logic to represent obligations on actions. We claim the Alethic component of the logic is redundant for the purposes of representing obligations on stative expressions in a contract. In the course of the analysis, we introduce polynormativity, which contrasts with the binormativity of standard DAL or alethic logic plus a violation proposition. We discuss the advantages of polynormativity in reasoning from violations and fulfillments.