Work · Aquinas
Summa Theologica
1265–1274 · Thousands of articles
The great cathedral of medieval thought, every question argued point and counter-point.
3
Parts
~3,000
Articles
1265–74
Written
Unfinished
Status
How every article works
The Summa is built from one unit repeated thousands of times: the article. It opens by arguing AGAINST itself at full strength (the objections), pivots on a single authority (“On the contrary”), delivers Aquinas’s own answer (“I answer that”), then answers every objection in turn. Fairness is built into the form, not added as a courtesy.
The shape of the argument
Prima Pars (I)
God’s existence (the Five Ways) and nature, the Trinity, and creation: everything flowing out from God.
I, Q2, A3
The Five Ways: five arguments from motion, cause, necessity, degree, and design, each ending by naming its conclusion “God.”
Prima Secundae (I-II)
The moral machine: the final end (happiness, ultimately God), human acts, the passions, virtue, and the treatise on law.
I-II, QQ90–97
Natural law: the basic moral truths any rational mind can read off human nature, part of God’s eternal law.
Secunda Secundae (II-II)
The virtues one at a time (faith, hope, charity, prudence, justice, courage, temperance) and the states of life.
Tertia Pars (III)
Christ, the Incarnation, and the sacraments: the road home. Left UNFINISHED after December 1273.
The Supplement
Compiled after his death from his earlier writings to close the gap the unfinished Third Part left open.
The cast
Aristotle — “the Philosopher,” cited constantly; the recovered pagan logic Aquinas turns on Christian doctrine
Augustine — the authority he answers and updates: “believe so that you may understand”
Averroes — “the Commentator” on Aristotle, admired and then argued against on the soul and the eternity of the world
Albert the Great — his teacher, who said the “dumb ox” would one day be heard worldwide
Scripture and the Fathers — the revealed authorities the “On the contrary” of each article leans on
The famous bits
The Five WaysI, Q2, A3
Five short arguments that the world points beyond itself (from motion, cause, necessity, degree, and design), each ending “and this we call God.”
Grace perfects natureI, Q1, A8
The keystone sentence: grace does not destroy nature but perfects it, so reason ministers to faith rather than bowing to it.
Natural lawI-II, QQ90–97
Right and wrong written into human nature and readable by anyone’s reason, not just divine command.
The form itselfevery article
State the strongest objections to its own answer first, then reply to them point by point.
“Like straw”after 6 Dec 1273
The mystical experience that stopped him: “all that I have written seems like straw to me.” He never wrote again.