Contextual deontic logic

In this article we propose contextual deontic logic (CDL). Contextual obligations are written as O(Alpha|Beta\\Gamma), and are to be read as `Alpha should be the case if Beta is the case, unless Gamma is the case'. The unless clause is analogous to the justification in Reiter's default rules. We show how contextual obligations can be used to solve certain aspects of contrary-to-duty paradoxes of dyadic deontic logic.