4 General Principles of Law

The third source — principles "recognized by civilized nations" the common content of the world's major municipal systems, available to fill international law's gaps (the PCIJ's answer to non liquet — no court may decline judgment for want of rule). The recognized examples (memorize a basket): res judicata; estoppel; good faith (pacta sunt servandum's home); nemo judex in causa sua (no one judge in own cause) and audi alteram partem (hear the other side — due process's twins); unjust enrichment; the rule that a wrong entails reparation (the Chorzów Factory's elevation to general principle — injury obliges full reparation); abuse of rights; prescription; the presumption against conflict with international obligations. Function: gap-filling and interpretive authority; nature: principles of law and logic, not equity's discretion (contrast ex aequo et bono below).