In many general histories of philosophy, Anselm's role is that of inventing the so-called Ontological Argument for the existence of God, which occupies about two pages in Chapters 2 and (some say) 3 of his Proslogion. The remaining 300 or so pages of close argument that make up his philosophical and theological writings are largely ignored, including the rest of the Proslogion itself. One purpose of this essay is to right that imbalance, at least as far as the Proslogion is concerned. The other chapters of the Proslogion are full of exciting philosophical discussion, on topics as varied as omnipotence, justice and eternity. Both Anselm's aims and his originality are obscured when the focus is concentrated on two brief chapters at the beginning of the book. Yet it would be a mistake to ignore entirely the special status of the Ontological Argument. It is not an accident that the shape of its reasoning has fascinated philosophers down the generations, and Anselm himself gave it special weight by including with the Proslogion the criticisms of this argument made by a contemporary, Gaunilo, a monk of Marmoutiers, along with his own replies to them.

Anselm's times and the background to the Proslogion

Anselm, who was born in 1033 and died in 1109, lived on the eve of one of the most brilliant periods of Western philosophy.