Deontic Logic
Georg Henrik von Wright · 2017
The treatment of the existential modes is usually known as quantification theory. The treatment of the alethic modes covers most of what is traditionally known as modal logic. The epistemic modes have not to any great extent and the deontic modes hardly at all been treated by logicians. The existence of logical truths which are peculiar to deontic concepts is what makes the study of Deontic Logic interesting. Deontic functions are similar to performance-functions in regard to disjunction, but not similar in regard to negation and conjunction. The deontic units of the deontic realm of given acts are logically independent of one another, meaning that they can be true or false in any combination of truth-values. In distributing truth-values over the deontic units people have to observe the restriction imposed by the Principle of Permission. The calculation of truth-values depends only upon the Principle of Deontic Distribution.