The Logic of Actual Obligation an Alternative Approach to Deontic Logic

The logic of actual obligation The logic of An alternative approach to deontic logic. In this paper we develop a system of deontic logic (LAO, the"; logic of actual obligation) with a.rathep limited scope: we are, only interested in obligations as far as they: are; relevant for deciding: what: actions-actually ought to be done in a particular situation, given some normative system, N. In fact we are interested how actual obligations are derived from the prima facie ones implied by N. Hence statements expressing that certain states of affairs are obligatory, such as the speed-limit ought to be 140 in stead of 100", fall out of the scope. (Roughly speaking LAO is what Castaneda calls a logic of "ought-to-do". (cf. [C]).) Since in LAO actions can be obligatory while assertions cannot, actions and assertions have to be strictly separated in the language of LAO. On this point we follow [M]. In [E] Job van Eck analyzes the relation between actual-and prima facie obligations in terms of tense. We don't agree with the details of his analysis, but we do believe that the role of time is important in deontic logic in general and in obtaining actual obligations from prima facie ones in particular. In section 1 we give a sketch of van Eck's system of temporally relative deontic logic (QDTL), to get some idea of the role of time in deontic logic. In section 2 QDTL is criticized, especially the fact that obligations are interpreted in terms of perfect alternatives. In LAO we start with prima facie duties which follow from some normative system N. (A typical example of such an N is a predominant system of morality in some society, which e.g. gives rise to the prima facie obligations not to lie, not to steal, etc.) In general it is possible to have conflicting prima facie obligations and LAO is intended to tell what actually ought to be done in such situations. The output is intended to be directive, i.e. action guiding. Hence we don't consider statements like if it is raining then you ought to have brought your umbrella with you, since such statements cannot give direction to (future) action. (In contrast 1 The logic of actual obligation 2 with It it is likely that it is going to rain, then you ought not to forget your umbrella".) It is important to note that we are not interested,-[n. …