Abstract

The paper - which celebrates the fortieth anniversary of Alchourrón's and Bulygin's seminal book Normative Systems - is devoted to analyzing the truth-conditions of normative propositions (i.e. descriptive statements bearing upon norms), and their relationship with the consistency of normative systems, especially of those - like legal systems - which are eminently composed of conditional norms. In the paper, two concepts of consistency are examined and their impact on the truth of normative propositions fully explored. It is also shown that, when the criteria for determining the consistency of normative systems are not univocally determined, normative propositions are undecidable as for their truth-value, i.e. it is not possible to univocally establish whether or not they are true. Finally, the difficulties in conciliating the logical and the practical treatments of inconsistent legal systems are tackled and provided with a theoretical explanation.