Anselm of Canterbury

Anselm was born at Aosta on the southern slope of the Alps, left home in his twenties and in 1060 entered the abbey of Bec in Normandy under the famous Lanfranc. Thirty years at Bec as monk, prior and abbot produced his main philosophical works. In 1093 he was made archbishop of Canterbury, and thereafter clashed repeatedly with William II and Henry I over the crown's power to appoint clergy, going into exile twice.

His motto was 'faith seeking understanding': believe first, then use reason to understand what is believed. The Monologion argues for God from degrees of goodness. The Proslogion presents what Kant later named the ontological argument: God is that than which nothing greater can be conceived; if it existed only in the mind, something greater, existing in reality as well, could be conceived; therefore God must exist in reality. A contemporary monk, Gaunilo, replied with a 'perfect island'; Anselm answered, and the debate continues today.

Why God Became Man argues by pure reason for the necessity of the Incarnation: human sin offends God's infinite dignity, and only one who is both God and man can make satisfaction. It was the first medieval attempt to argue a central doctrine systematically without relying on scriptural authority, and the scholastic method was established with it.