Person

Anselm

Archbishop of Canterbury (1093-1109); Italian-born Benedictine monk and theologian; AD 1033-1109. Originator of the ontological argument for God's existence and the satisfaction theory of atonement. The bridge between Augustinian-Platonist patristic thought and the Aristotelian-Thomist scholasticism that followed.

Biography

1033, Born at Aosta in northern Italy
1059, Joined the Benedictine abbey of Bec in Normandy under Lanfranc
1063, Prior of Bec
1078, Abbot of Bec
1093, Archbishop of Canterbury (succeeding Lanfranc)
1097-1100, Exile (dispute with William II)
1103-1107, Second exile (dispute with Henry I over investiture)
1109, Died at Canterbury

Major works

Monologion (1076)

A meditation on the divine essence, what reason alone can establish about God. Anselm seeks to show the existence and attributes of God sola ratione (by reason alone), without appeal to scripture for the foundational moves. A 79-chapter treatise.

Proslogion (1077-1078)

The work containing the ontological argument (chs. 2-3). The famous formulation:

"We believe You to be that than which a greater cannot be thought (aliquid quo nihil maius cogitari possit)."

The argument: if God is the greatest conceivable being, He must exist necessarily, since necessary existence is greater than contingent existence. See Modal Ontological Argument and Perfection Argument for the full treatment.

The Proslogion opens with the Augustinian formulation: fides quaerens intellectum, "faith seeking understanding." This phrase becomes the methodological motto of medieval scholasticism.

Cur Deus Homo (1098)

"Why God Became Man", Anselm's foundational work on atonement theology. Develops the satisfaction theory: humans owe an infinite debt of honor to God because of sin; this debt cannot be paid by any finite creature; only one who is both human (to owe the debt) and divine (to pay infinite satisfaction) can satisfy. Hence the necessity of the God-man (Christ).

This theory:

Decisively rejected the ransom-to-Satan model (Origen, Gregory of Nyssa) that had dominated patristic atonement theology
Anticipated and prepared for the Reformed penal substitution doctrine (Calvin)
Remains foundational in Catholic and Protestant atonement theology

Other works

De Veritate, on truth
De Libertate Arbitrii, on free will
De Casu Diaboli, on the fall of Satan
De Conceptu Virginali et de Originali Peccato, on the virgin conception and original sin
De Processione Spiritus Sancti, on the procession of the Holy Spirit (Filioque)
De Concordia, on grace and free will

Major contributions

1. The ontological argument

Anselm's Proslogion 2-3 contains the foundational ontological argument:

God is that than which nothing greater can be thought (definition)
Even the fool understands this concept
What exists both in understanding and in reality is greater than what exists in understanding alone
Therefore, God must exist in reality, otherwise He would not be the greatest conceivable

The argument has been:

Refuted by Gaunilo's "perfect island" objection (11th c.), Anselm replied that islands have no intrinsic maximum, but God does
Refuted (allegedly) by Kant's claim that existence is not a predicate (1781)
Defended in modal-logic form by Norman Malcolm (1960) and Alvin Plantinga (1974), see Modal Ontological Argument

The argument remains contested but has had distinguished defenders for nearly 1,000 years.

2. Satisfaction theory of atonement

Cur Deus Homo presents the satisfaction theory as a response to Boso's question: why did God become man?

The argument:

Sin against an infinite God incurs infinite debt
No mere creature can pay infinite debt
God could simply forgive, but this would compromise divine justice
Only a God-man can both owe the debt (as human) and pay it (as divine)
Therefore, the incarnation is necessary for redemption

Anselm's framework has been:

Adopted (with refinement toward penal-substitution) by the Reformed tradition (Calvin Institutes II.16-17; Westminster Confession 8)
Critiqued as overly transactional / juridical by liberal theology
Defended by modern Reformed scholarship (J. I. Packer, John Stott, Steve Jeffery et al. Pierced for Our Transgressions 2007)

3. Faith seeking understanding

The methodological motto fides quaerens intellectum shaped medieval theological method: faith provides the starting-point; reason explores and articulates faith's content. This is not fideism (faith against reason) nor rationalism (reason without faith) but a careful integration. Anselm thereby anticipated medieval scholasticism.

Anselm in the apologetic tradition

Anselm is referenced in:

Modal Ontological Argument, primary developer
Perfection Argument, primary developer
Christology, Cur Deus Homo satisfaction theory
Hell and Eternal Punishment, Anselm's "infinite debt for sin against infinite God" addresses proportionality objection
G2434 - hilasmos, G2435 - hilasterion, atonement-theory background

Reception history

Medieval

Anselm's ontological argument was largely set aside by Aquinas in favor of a posteriori arguments (Five Ways). Anselm's satisfaction theory of atonement was adopted and refined by Aquinas (Summa III, q. 46-49).

Reformation

The Reformation appealed to Anselm's atonement theology in transitioning toward penal substitution.

Modern

Anselm's ontological argument has been revived in:

Charles Hartshorne (The Logic of Perfection, 1962)
Norman Malcolm (1960)
Alvin Plantinga (The Nature of Necessity, 1974; God, Freedom, and Evil, 1974), modal-logic version
Robert M. Adams (1971), analyzing the original argument

Major secondary literature

R. W. Southern, Saint Anselm: A Portrait in a Landscape (1990)
G. R. Evans, Anselm and Talking About God (1978)
Brian Davies, The Thought of Anselm of Canterbury (Cambridge Companion, 2004)
Eleonore Stump, Aquinas (2003), comparative engagement
Sandra Visser & Thomas Williams, Anselm (2009)

Connection to codex concepts (added 2026-04-28 bulk extraction)

The 2026-04-28 §5.4 extraction built 99 new concept hubs that name Anselm as the foundational developer of the satisfaction-theory and ontological argument:

Penal Substitutionary Atonement, Cur Deus Homo (1098) gives the foundational satisfaction-theory; Christ's voluntary death has infinite worth and so satisfies the infinite debt of human sin against God's honor; the Reformers reframe Anselm's honor-frame to a justice / law-frame
Justification by Faith, Cur Deus Homo (c. 1098) frames the cross as satisfaction of divine honor, proto-substitutionary structure that the Reformers re-cast in legal terms
Biblical Forgiveness, Cur Deus Homo (1098); the satisfaction theory of atonement that grounds forgiveness in Christ's payment of the debt
Necessary vs Contingent Being, Proslogion (1078) treats God as a being whose non-existence is impossible; "central plank of Christian metaphysics from Augustine through Anselm, Aquinas..."
Principle of Sufficient Reason, Anselm and Aquinas hold an implicit PSR in cosmological arguments, though not formally stated as a general principle
Theories of Truth, De Veritate cited as part of the classical Christian correspondence-theory development (alongside Aquinas, Augustine)
Rationalism, Proslogion (1078); the fides quaerens intellectum project; the ontological argument as paradigm rationalist proof
Critical Thinking Christian Framework, Proslogion; fides quaerens intellectum as foundational Christian-philosophical commitment
Mary Sinless, Anselm (with Bernard of Clairvaux) was a notable medieval opponent of the Immaculate Conception, holding it incompatible with Mary's need for a Savior