Basic norm (German: Grundnorm) is a concept in the Pure Theory of Law created by Hans Kelsen, a jurist and legal philosopher. Kelsen used this word to denote the basic norm, order, or rule that forms an underlying basis for a legal system. The theory is based on a need to find a point of origin for all law, on which basic law and the constitution can gain their legitimacy (akin to the concept of first principles). This "basic norm", however, is hypothetical. This has led to criticism from noted authors such as H.L.A. Hart, who refers to the theory as a `needless duplication' of the `living reality' of the courts and officials actually identifying the law in accordance with the constitution's rules. It is mystifying to posit a rule beyond these rules, which adds, superfluously in Hart's view, that the constitution is to be obeyed.[1]
Kelsen also attempted to explain International Law by applying the concept of there being a Grundnorm superior to all the Grundnorms of the state. This theory has been severely criticised by theorists like Hart and Lord Lloyd.