ABSTRACT
This chapter examines the criteria against which the legal authority of non-state rules can be measured and the application of non-state rules as the most important of these criteria. It analyses how the application of non-state rules contributes to understanding their legal authority. Non-state rules gain in legal authority through a more frequent application by courts/tribunals as this contributes to their development from social norms or contractual rules to law or rules of law. The legal authority of non-state rules in that community differs from sector to sector and from region to region. To determine the legal authority of a specific non-state rule one can, look at the promulgator of the rule, the support it has, the content, and the application of the rule. When courts use non-state rules as normative legal scholarship/doctrine the authority of the rules is more uncertain. By studying the application of non-state rules in state courts their legal authority in domestic law can be understood.
