What sort of relation, according to the Pure Theory of Law, does a higher-order norm bear to a lower-order norm? Does the higher-order norm in effect subsume the lower-order norm? And if so, is subsumption sufficient for authorisation, such that subsumption of a norm under an appropriate higher-order norm authorises, say, a legal official's “choice” of that norm? This interpretation of authorisation in the Pure Theory of Law, fine as far as it goes, would be misleading if offered as a full statement. For Hans Kelsen in fact works with two types of authorisation, what I term material authorisation, wherein authorisation of a lower-order norm stems from the applicable higher-order norm, and formal authorisation, wherein authorisation of a lower-order norm flows from the power of the legal organ that creates, applies, or validates that norm.