ABSTRACT
This chapter examines how courts use non-state rules to interpret the law, as general principles of law, and accepted international commercial practices. It shows how courts use non-state rules to interpret domestic law and analyses how non-state rules are used as transnational commercial law doctrine. Codified non-state rules and case law are thus used to discover the Principles underlying the Convention for the International Sales of Goods and to find concrete rules to interpret these principles. Codified non-state rules are used to interpret and supplement domestic law, often as general principles of law or accepted commercial law doctrine. Codified non-state rules are thus used to interpret the law in both domestic and international contracts. Non-state rules are used to interpret domestic law and international conventions. As non-state rules are perceived to emerge from within the transnational business community, linking the decision of the court with non-state rules gives further legitimacy to the ruling.
