عنوان مقاله [English]
This research examines the relation between logic and ethics and tries to investigate logically the corresponding dilemmas. Standard Deontic Logic which is initially appeared for studying ethical propositions cannot offer a suitable and accurate solution for conflict between duties. Therefore some new deontic logics are made to represent this situation formally. For example Defeasible Deontic Logic and specially Reiter's Default Logic has a new approach to these moral dilemmas and offers an acceptable explanation of them.