The Proslogion: Philosophy and Logic

This article proposes an interpretation of St Anselm’s Proslogion that highlights its overall structure and theoretical core. The analysis is conducted in two stages: (a) discussion of the text and its previous interpretations in order to clarify Anselm’s premises and reasoning; (b) formal analysis of the arguments through symbolic logic, and comparison with other ontological arguments. More precisely, we describe a first-order theory corresponding to our interpretation of Anselm’s com-mitments and show that his conclusions follow from these axioms. The theses that this study will defend are the following: (a) the unum argumentum applies only to “id quo maius cogitari nequit” and not to other similar concepts, such as that of “most perfect being”; (b) the treatise has an overall unity that has an ascending trend; (c) our original formalization of the unum argumentum not only captures the essence of the Proslogion , but also clarifies some features of conceivability.