A Logical Analysis of the Main Argument in Chapter 2 of the Proslogion by Anselm of Canterbury

Abstract

The primary aim is the reconstruction of the main argument of the second chapter of Anselm’s Proslogion. To be proved is the statement that God, or something than which nothing greater can be thought, exists in reality. I proceed by a piecemeal analysis of every sentence of the Latin original and its subsequent translation into a formal second-order language with choice operator. Reconstructing Anselm’s reasoning demands interpretative input and additions. For example, the formula ‘quod maius est’ has to be suitably interpreted and expanded. Furthermore, I try to explicate Anselm’s maius predicate in terms of a perfection predicate and to develop a general proof for Anselm’s theorem, i.e. the statement that something/that than which something greater cannot be thought has all greater-making attributes.