Abstract

The contribution starts out by taking a critical look at some recent books, proceeding to reflect on three conceptual categories of the theory of invalidity: nullity, non-existence and inefficacy of an act or a norm. In particular, the author examines the evolution of the category of nullity of contract, observing how with regard to it the legislator and case law support more and more an axiological vision closely bound not to structural aspects but to consideration of the interests at stake. In illustrating theories concerning nullity of law and invalidity of administrative decisions, the author concentrates on the issues affecting concepts such as non-existence and inefficacy to conclude by focusing on the indispensable ordering function of law.