Best listing at p. 951. From within, implicit in the legal system . Implicit not rules of natural law or some other sort. This is generally derivative, i.e., applicable only in the absence of law or custom. Scholars are the prime practitioners of this, because this is a scientific function, but compare page 955.
Internal inconsistencies have to be resolved and gaps have to be filled.
New factual situations challenge the meaning of the unchanged text. Rules , generally statutory , found in substantive codes or procedural rules, if any. In interpreting the statute no other meaning can be attributed to it than that made clear by the actual significance of the words according to the connection between them, and by the intention of the legislature . Equity must be considered in the application of norms, but court rulings can only be based exclusively thereon when the law expressly allows it. While rules on the binding effect of judicial interpretation are rare, rules of interpretation are quite common.