The purpose of this work is to critically analyze Atria’s thesis whereby the three discrete meanings of legal positivism identified by Bobbio cannot be conceived of independently, but need each other to be understood. With this goal in mind, the article is divided into four sections. The first section presents Norberto Bobbio’s thesis on the need to differentiate between three meanings of the expression ‘legal positivism’ (1). The second section contains a reconstruction of Fernando Atria’s thesis according to which the three kinds of positivism are mutually explanatory, as well as each of the arguments that ground it (2). In the third section Atria’s thesis and its supporting arguments are critically analyzed (3). Finally, the main reasons to conclude that Atria fails to challenge the Bobbian distinction are briefly introduced (4)