Anselm of Canterbury

Quick Facts

• Name: Anselm of Canterbury
• Lived: 1033-1109 CE
• Born: Aosta, in the western Alps
• Main places: Bec in Normandy; Canterbury in England
• Roles: Benedictine monk, abbot, archbishop, theologian, philosopher
• Main tradition: Christian philosophy, early scholasticism, Augustinian theology
• Best known for: "faith seeking understanding," the ontological argument, and satisfaction theory of atonement
• Major works: Monologion, Proslogion, Cur Deus Homo

The Big Question

Anselm's big question was: can Christian faith understand itself without ceasing to be faith?

He did not think reason should replace trust in God. He also did not think believers should stop thinking once they believe. His motto was "faith seeking understanding." That means faith is the starting point, and reason is the tool faith uses to ask what it believes, why it believes it, and how its claims fit together.

For example, a Christian may already believe that God is perfectly good. Anselm then asks what "perfectly good" must mean. Is God one good thing among many good things? Or is God the source that makes all other goods good? Anselm's answer is the second one.

In One Minute

Anselm was an eleventh-century Christian thinker who helped shape medieval scholastic theology. He wrote as a monk, so his arguments often sound like prayers. But he also wrote with unusual logical force. He wanted Christian doctrine to be thought through, not merely repeated.

His most famous argument appears in the Proslogion. It says that if God means "that than which nothing greater can be conceived," then God cannot exist only as an idea. A greatest possible being that exists in reality would be greater than one that exists only in thought. This became known later as the ontological argument.

He also wrote Cur Deus Homo, which asks why God became human in Christ. His answer is called satisfaction theory. Sin creates a debt or disorder that humanity cannot repair. Christ, being both divine and human, restores what humanity owes to God.

What They Taught

Anselm taught that faith should become intelligent love. A believer begins by trusting God, but trust naturally wants clarity. If you love someone, you want to know them better. Anselm applies that pattern to theology: faith loves God, so faith seeks understanding of God.

This does not make Anselm a modern rationalist. He is not trying to build Christianity from scratch without Scripture, church teaching, or prayer. He reasons from inside Christian belief. But once he begins reasoning, he expects the reasoning to be serious. If Christians say God is supreme, necessary, just, merciful, and free, those words must be explained.

His early work Monologion takes a slow route. It argues that the good things we meet in the world point beyond themselves. A warm friendship is good. A truthful judgment is good. A generous action is good. These things are not goodness itself; they have goodness in limited ways. Anselm argues that there must be a highest good by which all lesser goods are good.

The Proslogion takes a shorter and more famous route. Anselm asks whether the very idea of God already shows that God exists. God is not just a very powerful being, like the strongest king in a story. God is "that than which nothing greater can be conceived." In plain language, God is the greatest possible reality.

Anselm then argues that the greatest possible reality cannot be only an idea in the mind. Suppose two painters imagine the same perfect cathedral, but one cathedral exists only in a sketch while the other is actually built. The built one is greater in an important way because it is real, not merely imagined. Anselm thinks something similar applies to God. If God existed only in thought, we could conceive of something greater: God existing in reality. So God must exist.

That argument is called ontological because it moves from the concept of God to God's being. "Ontology" means the study of being or what exists. Anselm does not begin with the world, as if pointing to stars, motion, or design. He begins with what the word "God" means.

Anselm also taught that God is not one item inside the universe. God is the source of all being, goodness, truth, and justice. Created things can be good, true, or just in partial ways. God is not partially good. God is goodness itself.

His account of salvation in Cur Deus Homo is just as important. The title means "Why God Became Man." Anselm rejects the idea that salvation is just God deciding to overlook sin. Sin is a failure to give God what is owed: love, obedience, honor, and right order. Imagine a public betrayal that damages trust and justice. A judge cannot make things right by pretending it never happened. For Anselm, God is perfectly merciful, but mercy does not erase justice.

Human beings owe satisfaction, meaning a real act that restores the damaged order. But sinful humanity cannot offer enough. Christ can, because Christ is truly human and truly divine. As human, Christ acts on humanity's behalf. As divine, his self-offering has a worth no ordinary creature could supply. That is Anselm's satisfaction theory of atonement.

Key Ideas With Examples

• Faith seeking understanding: Faith starts the search; reason deepens it. Example: a believer trusts that God is just, then asks how divine justice and mercy can both be true.

• Ontological argument: An argument for God's existence based on the idea of God as the greatest possible being. Example: if "God" means the greatest conceivable reality, Anselm says God cannot be like an imaginary island or palace, existing only in the mind.

• Necessary existence: Something exists necessarily if it cannot fail to exist. Example: a tree could have failed to grow, because it depends on soil, weather, and seed. Anselm thinks God is not like that. God does not depend on anything else.

• Supreme good: God is not merely very good but the source of all goodness. Example: many lamps can be bright because they receive power from elsewhere. Anselm thinks created goods are like that: they have goodness by dependence on the highest good.

• Satisfaction theory: Sin creates a disorder that must be repaired, not ignored. Example: if someone destroys another person's home, saying "sorry" matters, but repair is also needed. Anselm applies this repair idea to the relation between humanity and God.

• Freedom of will: Freedom is not just choosing whatever impulse appears. For Anselm, freedom is the power to preserve uprightness of will for its own sake. Example: a person who tells the truth under pressure is freer than a person who lies because fear controls them.

• Truth as rightness: Truth is a kind of fittingness or correctness. Example: a statement is true when it says what is the case; an action is true when it fits what justice requires.

• Major objections: Gaunilo argued that Anselm's logic could "prove" a perfect lost island, which seems absurd. Aquinas later argued that humans do not know God's essence clearly enough to prove God's existence from the concept alone. Kant later objected that existence is not a normal property that makes a thing greater, like being tall or wise.

Major Works

• Monologion: A long meditation on God that tries to reason about divine existence and attributes without leaning directly on biblical proof-texts. It argues from the goodness, greatness, and existence of created things toward one supreme source.

• Proslogion: A shorter, prayer-shaped work that looks for one argument showing that God exists and has the highest divine attributes. It contains the famous ontological argument.

• Cur Deus Homo: A dialogue on why God became human. It gives Anselm's satisfaction theory: Christ restores the justice and honor damaged by sin.

• De Veritate: A dialogue on truth as rightness in thought, speech, action, and being.

• De Libertate Arbitrii: A dialogue on free choice. It argues that freedom is ordered toward justice, not mere option-picking.

• De Casu Diaboli: A dialogue on the fall of the devil, using that problem to discuss evil, justice, will, and responsibility.

Why It Matters

Anselm matters because he made rigorous argument feel native to Christian theology. He did not treat logic as an enemy of devotion. In his best work, prayer and argument belong together.

His ontological argument became one of the most debated arguments in philosophy of religion. Later thinkers such as Descartes, Leibniz, Hegel, and some modern philosophers developed versions of it. Many others rejected it. The debate matters because it asks whether reason can move from an idea to reality.

His satisfaction theory also reshaped Western Christian accounts of atonement. Later theologians accepted, revised, or attacked it, especially when asking whether salvation is mainly about honor, debt, punishment, moral transformation, victory over evil, or some combination of these.

Proponents, Critics, and Opponents

• Augustine of Hippo: Anselm inherits Augustine's inward, prayerful search for understanding and Augustine's view of God as truth and supreme good.

• Boethius: Anselm inherits Latin tools for thinking about necessity, divine attributes, and rational theology.

• Gaunilo of Marmoutiers: Gaunilo gave the first famous objection to the ontological argument. His "perfect island" example asks why the same logic could not prove the existence of other perfect imaginary things. Anselm replied that the argument applies only to the greatest conceivable being, not to limited things such as islands.

• Thomas Aquinas: Aquinas respected Anselm but rejected the ontological argument as a proof available to human reason. He thought we know God from effects in the world before we know what God is in himself.

• John Duns Scotus: Scotus continued the Anselmian interest in necessity, infinity, and rational proof of God, though in a more technical scholastic form.

• Peter Abelard: Abelard shared Anselm's confidence that theology should use reason, but he pushed against Anselm's satisfaction account of atonement and gave more weight to Christ's moral influence on human love.

• Immanuel Kant: Kant gave one of the most famous later objections to ontological arguments. He argued that existence is not a property that can be added to a concept to make it greater.

Related Pages

• Augustine of Hippo
• Boethius
• Peter Abelard
• Thomas Aquinas
• John Duns Scotus
• Scholasticism
• Proslogion
• Monologion
• Cur Deus Homo