Anselm of Canterbury

Anselm of Canterbury (c. 1033–1109) was an Italian-born Benedictine monk, theologian, and archbishop of Canterbury. He developed the ontological argument for God’s existence and shaped medieval Christian theology.

Ontological argument: An argument that derives God’s existence from the concept of God. Anselm’s best-known reasoning begins from the idea of God as that than which nothing greater can be conceived.
Reductio ad absurdum: A form of reasoning that establishes a claim by deriving a contradiction from its negation. Anselm uses reductio reasoning to argue that God cannot exist only in the understanding.
Aosta: A town in the western Alps, now in Italy, where Anselm was born. Anselm’s early life began in this Alpine region before he entered monastic life.
William II of England: King of England from 1087 to 1100, whose reign included conflict with Anselm. William’s dispute with Anselm over church revenues and authority led to the archbishop’s exile.
Cur Deus Homo: Anselm’s treatise explaining why God became human, centered on satisfaction for sin. This work gave lasting influence to Anselm’s account of the Incarnation and atonement.
Proslogion: Anselm’s theological work presenting a meditation on God and the ontological argument. This is where Anselm develops his celebrated proof through prayerful reasoning.
Gaunilo's perfect island objection: A parody arguing that Anselm’s reasoning could wrongly prove the existence of a perfect island. Gaunilo challenges whether the argument can move from a definition to real existence.
Bec Abbey: A Benedictine monastery in Normandy that became a major center of learning. Anselm joined Bec and became its prior and later abbot.
Henry I of England: King of England from 1100 to 1135, who contested with Anselm over investiture. Anselm’s conflict with Henry helped define the limits of royal control over church appointments.
Satisfaction theory of atonement: A theory that Christ’s death satisfies the debt or honor owed to God because of sin. Anselm’s Cur Deus Homo became the classic medieval formulation of this account.

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