Gödel’s theory revolutionized mathematical logic. It is based on the assumption of the non-demonstrability of the axioms in a given closed logic system. From these premises this work aims to address the issue of the non-derivability/non-decidability of law as emerging from Hans Kelsen’s Reine Rechtslehre. Therefore we will offer a critical and problematic comparison between Gödel and Kelsen, considered as epigones of a certain epistemologicalformalism.