Cur Deus Homo
Why God Became Man — Anselm's satisfaction theory of the Atonement, in two-book dialogue with his pupil Boso
Tradition: Medieval Christian theology / Anselmian scholasticism
Sin is an infinite offence against God's honour requiring infinite satisfaction — which only the God-man can offer
Cur Deus Homo is Anselm's major theological work and the founding text of the medieval satisfaction theory of the Atonement. Across a two-book dialogue with his pupil Boso, Anselm argues "by necessary reasons" — i.e., without appeal to scriptural authority but by philosophical demonstration — for the necessity of the Incarnation. The argument: human sin is an infinite offence against God's infinite honour; the offence requires satisfaction proportionate to the dishonour; no creature can offer satisfaction proportionate to infinite offence; therefore only God, becoming a man while remaining God, can offer the necessary satisfaction. The work shaped medieval and Reformation soteriology — Aquinas modifies it; Calvin develops a penal-substitution variant; modern critiques (Aulén's Christus Victor, the moral-influence theory) define themselves against it.
Author
Editions cited
- Anselm: Basic Writings (Thomas Williams, Hackett, 2007)
- The Major Works (Brian Davies & G. R. Evans, Oxford, 1998)
School Embodiments
Aquinas's atonement theology (Summa III.46-49) develops Anselm's satisfaction theory while modifying it. Catholic soteriology has been broadly Anselmian for nearly a millennium.
"Whoever does not render to God this honour due Him takes from God what is His." (Cur Deus Homo I.11)
Calvin's penal-substitution theory of atonement is a Reformation modification of Anselm's satisfaction theory. Reformed orthodoxy (Turretin, Hodge, Vos) treats Anselm as a central source.
"You have not yet weighed the gravity of sin." (Cur Deus Homo I.21 — Anselm to Boso)
Luther retains Anselmian satisfaction theory while sharpening the penal aspect. Lutheran orthodoxy and the Formula of Concord operate within the broadly Anselmian framework.
"The God-man alone can pay what we owe." (Cur Deus Homo II.6, paraphrasing)
Anselm's method — "necessary reasons" (rationes necessariae), demonstrating Christian doctrines by philosophical demonstration — is the most rigorous medieval anticipation of rationalist theology.
"As though Christ had never been spoken of, by necessary reasons alone." (Cur Deus Homo, methodological premise)
Modern evangelical theology has been Anselmian-penal-substitutionary in its mainstream soteriology. Recent challenges (Steve Chalke, Tony Jones) define themselves against this inherited Anselmian framework.
"Christ's death satisfies the demands of divine justice." (Anselmian-evangelical consensus, summarising Cur Deus Homo II.6-7)
Orthodox theology has been critical of Anselm's satisfaction theory — preferring the "Christus Victor" / ransom motifs of the Greek patristic tradition. The Orthodox-Catholic soteriological divergence runs partly through Cur Deus Homo.
"It was fitting that He be both God and man." (Cur Deus Homo II.6)
Liberal Protestant theology has been critical of Anselmian satisfaction theology, often preferring moral-influence or liberation-theological alternatives. Abelard's twelfth-century moral-influence response is the classical alternative.
"God's mercy and justice meet at the cross." (paraphrasing the Anselmian framework that liberal theology contests)
Anselm's working method assumes that real theological truths can be reached by demonstration — a robust theological realism.
"By reason alone — sola ratione — we shall investigate." (Cur Deus Homo I.1)
Internal Tensions
Anselm's feudal-honour framework — modelled on the lord-vassal relations of his society — has been criticised as time-bound. The substitution-language has been criticised by Christus-Victor advocates (Aulén, 1931) as missing the cosmic-conflict dimensions of patristic atonement theology. Modern Reformed and evangelical defenders (Stott, Jeffery-Ovey-Sach) have developed sophisticated responses.
I. Time
The Incarnation is a real temporal event in real history. Standard medieval Christian framework.
Attributes
II. Space
Standard background.
Attributes
III. Matter
Real bodily existence is the medium of the incarnation and the cross.
Attributes
IV. Observer
The Anselmian observer is the rational believer reaching theological understanding through demonstration ("faith seeking understanding"). Active, plural, embodied; metaphysical agency unambiguously personal.
Attributes
V. Energy
Standard medieval doctrine of divine sustenance.
Attributes
VI. Information
Christ's atoning work is a real historical-cosmic event whose informational consequences are eternal. Personal information conserved through resurrection.
Attributes
Personas with the nearest attribute fingerprint
Historical figures whose own classification on the same six-dimensional grid lands closest to this work's. Computed by attribute-agreement on coordinates both address.
Computed school proximity
The work's attribute fingerprint scored against all schools using the same quiz scorer. Useful as a sanity check on the hand-curated embodiments above.
How Cur Deus Homo resolves each dilemma
48 resolved positions across 4 dimensions, including 7 distinctive where the majority of schools go the other way · 9 unaligned.
Each dimension is sorted so minority positions come first. Mainstream positions are folded into an expandable list.
Time · 9 dilemmas, all mainstream
Matter · 7 dilemmas, all mainstream
Observer · 37 dilemmas · 5 distinctive
Mind, agency, and the knower's relation to the known.