As a general principle of rationality in reaching conclusions in disputed matters, "Hear both sides" was treated as part of common wisdom by the ancient Greek dramatists.[4] A similar principle can also be found in Islamic law, based on a hadith indicating that in litigation, both parties must be heard.[5] The principle was referred to by the International Court of Justice in the Nuclear Tests case, referring to France's non-appearance at judgment.[6] Modern legal systems differ on whether individuals can be convicted in absentia.