Jaap Hage studierte Rechtswissenschaften und Philosophie an der Universität Leiden. Nachdem er für eine kurze Zeit auf dem Gebiet der Informatik forschte, lehrt und arbeitet er seit 1978 als Professor für Allgemeine Rechtslehre zunächst an der Universität Leiden und heute an der Universität Maastricht. Zu seinen bisherigen Veröffentlichungen gehören die Werke „Feiten en betekenis“ (Dissertation zur Praktischen Vernunft), „Reasoning with Rules“, und „Studies in Legal Logic“.
In the jurisprudential literature, the notions of legal power and legal competence are usually not well distinguished. The present article tries to develop such a clear distinction.
The existence of a legal power is described as a side-effect of legal rules that make it possible to bring about particular results. For example, Charlène has the legal power to reduce her tax obligations by moving from Belgium to Monaco. (The example is on purpose not of a juridical act.) Legal powers can be the side-effect of the existence of counts-as, fact-to-fact, and dynamic rules.
A legal capacity is described as a status, attributed by a legal rule, which is a necessary prerequisite for bringing about legal consequences by means of a juridical act. For example, Parliament has the competence to create statutes. Without this competence an attempt to make a statute would be invalid.
The concept of a legal competence is in first instance an internal legal concept, meaning that it is a concept used in legal rules. In this respect it differs from the concept of a legal power, which is not used in legal rules, even though legal powers exist because of legal rules. The concept of a legal power is an external legal concept.
If a legal power is to be exercised by means of a juridical act, but only then, the competence to do so is a necessary condition for the existence of this power.