Validity and invalidity are properties of legal rules. Both concepts refer to relationships-relationships between a given rule and the second-order rules that govern its creation and contents.
Indeed, it is a well-known feature of modern legal systems that law regulates, among other things, the creation of law itself. This amounts to saying that each legal system includes a large variety of second-order rules that govern the production of further legal rules along with ordinary rules of behavior, such as the rules of criminal law. Second-order rules regulate both the rule-making process and, to a certain extent, the contents of forthcoming rules. In this way, each legal system states the conditions of validity for its own forthcoming rules.
A rule is valid only if it is in accordance with all of the secondorder rules that govern its creation and its contents. As a consequence, a rule is deemed invalid if it is not in accordance with at least one second-order rule
