Abstract. A restatement of an institutionalist theory of law is attempted with particular reference to legal reasoning and legal rights. Use is made of Ota Weinberger's concept of “practical information”, focusing on both its momentary and diachronic aspects. Momentary practical information corresponds to the need to know which conduct is required of us at a given moment. The diachronic practical information becomes relevant whenever we wish to stabilize the practical information and to reduce the likelihood of change regarding our ways of acting. Furthermore, the momentary information is given sense only against the background of the diachronic one. Among the different types of diachronic practical information particular importance is ascribed to legal “institutions” such as contracts and rights. Legal “institutions” are conceived as founded on various sets of rules. Rules may then increase the number of facts in the world: those special kinds of facts which are represented by social phenomena.