This chapter posits that international law, like all law, can be understood as a hybrid of positive and natural law. The history of natural law from Ancient Greece to today’s global community reveals that the method used for centuries to explain extra-positive features of law consists of three integral elements. The method uses reason, reflection on nature, and openness to transcendence. Certain contemporary natural law theorists, however, prefer to focus on reason and nature alone. Yet, the history of natural law thinking shows that transcendence is integral to the method. History also reveals that religion is not the only avenue to transcendence. Transcendence completes a natural law method capable of explaining persuasively why law binds...