St Thomas Aquinas · 1265–1273

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The greatest work of Catholic theology, made easy to read: every article with its Latin beside the classic English, a way to find any question in seconds, and a guide to where to begin.

Try happiness, angels, anger or I-II 94 2.

4Parts
512Questions
2,669Articles

I, q. 2, a. 3The Five Ways

Whether God Exists?

Respondeo I answer that

Respondeo dicendum quod Deum esse quinque viis probari potest.

I answer that, The existence of God can be proved in five ways.

Latin · English Read the article →

Thomas's own preface

We purpose in this book to treat of whatever belongs to the Christian Religion, in such a way as may tend to the instruction of beginners.

Propositum nostrae intentionis in hoc opere est, ea quae ad Christianam religionem pertinent, eo modo tradere, secundum quod congruit ad eruditionem incipientium.

He wrote it for beginners. Begin with the first article →

How to read it

How to read the Summa: every article is a debate, in four moves.

The Summa is built of 2,669 short articles, each asking one yes-or-no question. Once you know the pattern, you can open it anywhere.

  1. Step 1 Videtur quod Objections

    Thomas begins with the strongest case against his own answer, stated fairly.

  2. Step 2 Sed contra On the contrary

    An authority, usually Scripture or a Father, that points the other way.

  3. Step 3 Respondeo I answer that

    His own answer, argued. The heart of every article.

  4. Step 4 Ad primum Replies

    Each objection answered in turn, often granting what was true in it.

New to it? Read the question, then jump to I answer that, then go back for the objections. The reader's Answer only switch does exactly that.

Articles worth reading first

Where to start reading the Summa.

The Summa runs to thousands of pages. These are the articles we would hand a friend: the famous ones, the beautiful ones, and a few that will surprise you.

Happiness and how to live

The Second Part opens with the question everyone asks: what would make me happy?

I-II, q. 2, a. 8 Could anything in this world make you happy? “impossibile est beatitudinem hominis esse in aliquo bono creato.” It is impossible for any created good to constitute man's happiness. Question 2 tries everything people chase (wealth, honour, fame, power, health, pleasure) and finds each one wanting. This last article says why: the will wants the whole of goodness, and only God is that. Read the article I-II, q. 3, a. 8 What is perfect happiness? “ultima et perfecta beatitudo non potest esse nisi in visione divinae essentiae.” Final and perfect happiness can consist in nothing else than the vision of the Divine Essence. Thomas's answer to the question of the whole moral life: to see God. Everything in the Second Part is a road toward this. Read the article I-II, q. 38, a. 5 Do sleep and a bath help when you're sad? “per huiusmodi remedia corporalia tristitia mitigatur.” sorrow is assuaged by such like bodily remedies. Yes. The great theologian prescribes them, citing St Augustine, who took a bath after his mother died. The articles around it give his other remedies for sorrow: any pleasure, tears, the sympathy of friends, and contemplating the truth. Read the article I-II, q. 94, a. 2 What is the first rule of the moral life? “bonum est faciendum et prosequendum, et malum vitandum.” good is to be done and pursued, and evil is to be avoided. The root of natural law, from which every other precept grows. Short, clear and endlessly quoted. Read the article

Love, justice and the virtues

The Second Part of the Second Part, where Thomas gets practical, and sometimes surprising.

II-II, q. 23, a. 8 What holds all the virtues together? “Et pro tanto dicitur esse forma virtutum” charity is called the form of the virtues Charity directs every other virtue to God, the way a soul gives life to a body. Without it, the other virtues are not yet fully themselves. Read the article II-II, q. 66, a. 7 Is it theft to take bread when you're starving? “res quas aliqui superabundanter habent, ex naturali iure debentur pauperum sustentationi.” whatever certain people have in superabundance is due, by natural law, to the purpose of succoring the poor. Thomas says no: in real and urgent need, things are held in common. Seven centuries before modern debates about property, this is the Church's tradition on what we owe the poor. Read the article II-II, q. 64, a. 7 May you kill in self-defence? “nihil prohibet unius actus esse duos effectus, quorum alter solum sit in intentione, alius vero sit praeter intentionem.” Nothing hinders one act from having two effects, only one of which is intended, while the other is beside the intention. The birthplace of the principle of double effect: an act can have two effects, one intended and one not. Still at the heart of medical and military ethics. Read the article II-II, q. 40, a. 1 Can a war ever be just? “ad hoc quod aliquod bellum sit iustum, tria requiruntur.” In order for a war to be just, three things are necessary. Three conditions: lawful authority, a just cause, a right intention. The core of just war teaching to this day. Read the article II-II, q. 168, a. 2 Is there a virtue of having fun? “si moderate fiat, licet uti ludo.” if this be done with moderation, it is lawful to make use of fun. There is, and its name is eutrapelia. The soul tires like the body and needs play to rest. Two articles later Thomas names the opposite vice: never joking at all. Read the article II-II, q. 188, a. 6 Which is better, prayer or action? “ita maius est contemplata aliis tradere quam solum contemplari.” so is it better to give to others the fruits of one's contemplation than merely to contemplate. Better than either alone is to contemplate and hand on what you have contemplated. The line became the motto of Thomas's own Dominican Order. Read the article

The whole Summa

The Summa Theologiae: four parts, 512 questions.

From God, to man's journey back to Him, to Christ who is the way. Open a treatise to see its questions.

Prima Pars 119 questions · 584 articles

First Part

God: that He is, what He is, the Trinity, and everything that comes forth from Him, angels and men included.

Sacred Doctrine q. 1
  1. 1 The Nature and Extent of Sacred Doctrine 10 art.
The One God qq. 2–26
  1. 2 The Existence of God 3 art.
  2. 3 On the Simplicity of God 8 art.
  3. 4 The Perfection of God 3 art.
  4. 5 Of Goodness in General 6 art.
  5. 6 The Goodness of God 4 art.
  6. 7 The Infinity of God 4 art.
  7. 8 The Existence of God in Things 4 art.
  8. 9 The Immutability of God 2 art.
  9. 10 The Eternity of God 6 art.
  10. 11 The Unity of God 4 art.
  11. 12 How God Is Known by Us 13 art.
  12. 13 The Names of God 12 art.
  13. 14 Of God's Knowledge 16 art.
  14. 15 Of Ideas 3 art.
  15. 16 Of Truth 8 art.
  16. 17 Concerning Falsity 4 art.
  17. 18 The Life of God 4 art.
  18. 19 The Will of God 12 art.
  19. 20 God's Love 4 art.
  20. 21 The Justice and Mercy of God 4 art.
  21. 22 The Providence of God 4 art.
  22. 23 Of Predestination 8 art.
  23. 24 The Book of Life 3 art.
  24. 25 The Power of God 6 art.
  25. 26 Of the Divine Beatitude 4 art.
The Most Holy Trinity qq. 27–43
  1. 27 The Procession of the Divine Persons 5 art.
  2. 28 The Divine Relations 4 art.
  3. 29 The Divine Persons 4 art.
  4. 30 The Plurality of Persons in God 4 art.
  5. 31 Of What Belongs to the Unity or Plurality in God 4 art.
  6. 32 The Knowledge of the Divine Persons 4 art.
  7. 33 Of the Person of the Father 4 art.
  8. 34 Of the Person of the Son 3 art.
  9. 35 Of the Image 2 art.
  10. 36 Of the Person of the Holy Ghost 4 art.
  11. 37 Of the Name of the Holy Ghost--Love 2 art.
  12. 38 Of the Name of the Holy Ghost, as Gift 2 art.
  13. 39 Of the Persons in Relation to the Essence 8 art.
  14. 40 Of the Persons as Compared to the Relations or Properties 4 art.
  15. 41 Of the Persons in Reference to the Notional Acts 6 art.
  16. 42 Of Equality and Likeness Among the Divine Persons 6 art.
  17. 43 The Mission of the Divine Persons 8 art.
Creation qq. 44–49
  1. 44 The Procession of Creatures from God, and of the First Cause of All Things 4 art.
  2. 45 The Mode of Emanation of Things from the First Principle 8 art.
  3. 46 Of the Beginning of the Duration of Creatures 3 art.
  4. 47 Of the Distinction of Things in General 3 art.
  5. 48 The Distinction of Things in Particular 6 art.
  6. 49 The Cause of Evil 3 art.
The Angels qq. 50–64
  1. 50 Of the Substance of the Angels Absolutely Considered 5 art.
  2. 51 Of the Angels in Comparison with Bodies 3 art.
  3. 52 Of the Angels in Relation to Place 3 art.
  4. 53 Of the Local Movement of the Angels 3 art.
  5. 54 Of the Knowledge of the Angels 5 art.
  6. 55 Of the Medium of the Angelic Knowledge 3 art.
  7. 56 Of the Angels' Knowledge of Immaterial Things 3 art.
  8. 57 Of the Angels' Knowledge of Material Things 5 art.
  9. 58 Of the Mode of the Angelic Knowledge 7 art.
  10. 59 The Will of the Angels 4 art.
  11. 60 Of the Love or Dilection of the Angels 5 art.
  12. 61 Of the Production of the Angels in the Order of Natural Being 4 art.
  13. 62 Of the Perfection of the Angels in the Order of Grace and of Glory 9 art.
  14. 63 The Malice of the Angels with Regard to Sin 9 art.
  15. 64 The Punishment of the Demons 4 art.
The Work of the Six Days qq. 65–74
  1. 65 The Work of Creation of Corporeal Creatures 4 art.
  2. 66 On the Order of Creation Towards Distinction 4 art.
  3. 67 On the Work of Distinction in Itself 4 art.
  4. 68 On the Work of the Second Day 4 art.
  5. 69 On the Work of the Third Day 2 art.
  6. 70 On the Work of Adornment, as Regards the Fourth Day 3 art.
  7. 71 On the Work of the Fifth Day 1 art.
  8. 72 On the Work of the Sixth Day 1 art.
  9. 73 On the Things That Belong to the Seventh Day 3 art.
  10. 74 On All the Seven Days in Common 3 art.
Man qq. 75–102
  1. 75 Of Man Who Is Composed of a Spiritual and a Corporeal Substance: and in the First Place, Concerning What Belongs to the Essence of the Soul 7 art.
  2. 76 Of the Union of Body and Soul 8 art.
  3. 77 Of Those Things Which Belong to the Powers of the Soul in General 8 art.
  4. 78 Of the Specific Powers of the Soul 4 art.
  5. 79 Of the Intellectual Powers 13 art.
  6. 80 Of the Appetitive Powers in General 2 art.
  7. 81 Of the Power of Sensuality 3 art.
  8. 82 Of the Will 5 art.
  9. 83 Of Free-Will 4 art.
  10. 84 How the Soul While United to the Body Understands Corporeal Things Beneath It 8 art.
  11. 85 Of the Mode and Order of Understanding 8 art.
  12. 86 What Our Intellect Knows in Material Things 4 art.
  13. 87 How the Intellectual Soul Knows Itself and All Within Itself 4 art.
  14. 88 How the Human Soul Knows What Is Above Itself 3 art.
  15. 89 Of the Knowledge of the Separated Soul 8 art.
  16. 90 Of the First Production of Man's Soul 4 art.
  17. 91 The Production of the First Man's Body 4 art.
  18. 92 The Production of the Woman 4 art.
  19. 93 The End or Term of the Production of Man 9 art.
  20. 94 Of the State and Condition of the First Man as Regards His Intellect 4 art.
  21. 95 Of Things Pertaining to the First Man's Will--Namely, Grace and Righteousness 4 art.
  22. 96 Of the Mastership Belonging to Man in the State of Innocence 4 art.
  23. 97 Of the Preservation of the Individual in the Primitive State 4 art.
  24. 98 Of the Preservation of the Species 2 art.
  25. 99 Of the Condition of the Offspring As to the Body 2 art.
  26. 100 Of the Condition of the Offspring As Regards Righteousness 2 art.
  27. 101 Of the Condition of the Offspring As Regards Knowledge 2 art.
  28. 102 Of Man's Abode, Which Is Paradise 4 art.
The Government of Creatures qq. 103–119
  1. 103 Of the Government of Things in General 8 art.
  2. 104 The Special Effects of the Divine Government 4 art.
  3. 105 Of the Change of Creatures by God 8 art.
  4. 106 How One Creature Moves Another 4 art.
  5. 107 The Speech of the Angels 5 art.
  6. 108 Of the Angelic Degrees of Hierarchies and Orders 8 art.
  7. 109 The Ordering of the Bad Angels 4 art.
  8. 110 How Angels Act on Bodies 4 art.
  9. 111 The Action of the Angels on Man 4 art.
  10. 112 The Mission of the Angels 4 art.
  11. 113 Of the Guardianship of the Good Angels 8 art.
  12. 114 Of the Assaults of the Demons 5 art.
  13. 115 Of the Action of the Corporeal Creature 6 art.
  14. 116 On Fate 4 art.
  15. 117 Of Things Pertaining to the Action of Man 4 art.
  16. 118 Of the Production of Man from Man As to the Soul 3 art.
  17. 119 Of the Propagation of Man As to the Body 2 art.
Prima Secundae 114 questions · 619 articles

First Part of the Second Part

Man's return to God, in general: happiness, freedom, the passions, virtue and sin, law and grace.

The Last End: Happiness qq. 1–5
  1. 1 Of Man's Last End 8 art.
  2. 2 Of Those Things in Which Man's Happiness Consists 8 art.
  3. 3 What Is Happiness 8 art.
  4. 4 Of Those Things That Are Required for Happiness 8 art.
  5. 5 Of the Attainment of Happiness 8 art.
Human Acts qq. 6–21
  1. 6 Of the Voluntary and the Involuntary 8 art.
  2. 7 Of the Circumstances of Human Acts 4 art.
  3. 8 Of the Will, in Regard to What It Wills 3 art.
  4. 9 Of That Which Moves the Will 6 art.
  5. 10 Of the Manner in Which the Will Is Moved 4 art.
  6. 11 Of Enjoyment, Which Is an Act of the Will 4 art.
  7. 12 Of Intention 5 art.
  8. 13 Of Choice, Which Is an Act of the Will with Regard to the Means 6 art.
  9. 14 Of Counsel, Which Precedes Choice 6 art.
  10. 15 Of Consent, Which Is an Act of the Will in Regard to the Means 4 art.
  11. 16 Of Use, Which Is an Act of the Will in Regard to the Means 4 art.
  12. 17 Of the Acts Commanded by the Will 9 art.
  13. 18 Of the Good and Evil of Human Acts, in General 11 art.
  14. 19 Of the Goodness and Malice of the Interior Act of the Will 10 art.
  15. 20 Of Goodness and Malice in External Human Actions 6 art.
  16. 21 Of the Consequences of Human Actions by Reason of Their Goodness and Malice 4 art.
The Passions qq. 22–48
  1. 22 Of the Subject of the Soul's Passions 3 art.
  2. 23 How the Passions Differ from One Another 4 art.
  3. 24 Of Good and Evil in the Passions of the Soul 4 art.
  4. 25 Of the Order of the Passions to One Another 4 art.
  5. 26 Of the Passions of the Soul in Particular: and First, of Love 4 art.
  6. 27 Of the Cause of Love 4 art.
  7. 28 Of the Effects of Love 6 art.
  8. 29 Of Hatred 6 art.
  9. 30 Of Concupiscence 4 art.
  10. 31 Of Delight Considered in Itself 8 art.
  11. 32 Of the Cause of Pleasure 8 art.
  12. 33 Of the Effects of Pleasure 4 art.
  13. 34 Of the Goodness and Malice of Pleasures 4 art.
  14. 35 Of Pain or Sorrow, in Itself 8 art.
  15. 36 Of the Causes of Sorrow or Pain 4 art.
  16. 37 Of the Effects of Pain or Sorrow 4 art.
  17. 38 Of the Remedies of Sorrow or Pain 5 art.
  18. 39 Of the Goodness and Malice of Sorrow or Pain 4 art.
  19. 40 Of the Irascible Passions, and First, of Hope and Despair 8 art.
  20. 41 Of Fear, in Itself 4 art.
  21. 42 Of the Object of Fear 6 art.
  22. 43 Of the Cause of Fear 2 art.
  23. 44 Of the Effects of Fear 4 art.
  24. 45 Of Daring 4 art.
  25. 46 Of Anger, in Itself 8 art.
  26. 47 Of the Cause That Provokes Anger, and of the Remedies of Anger 4 art.
  27. 48 Of the Effects of Anger 4 art.
Habits qq. 49–54
  1. 49 Of Habits in General, As to Their Substance 4 art.
  2. 50 Of the Subject of Habits 6 art.
  3. 51 Of the Cause of Habits, As to Their Formation 4 art.
  4. 52 Of the Increase of Habits 3 art.
  5. 53 How Habits Are Corrupted or Diminished 3 art.
  6. 54 Of the Distinction of Habits 4 art.
Virtues qq. 55–70
  1. 55 Of the Virtues, As to Their Essence 4 art.
  2. 56 Of the Subject of Virtue 6 art.
  3. 57 Of the Intellectual Virtues 6 art.
  4. 58 Of the Difference Between Moral and Intellectual Virtues 5 art.
  5. 59 Of the Moral Virtues in Relation to the Passions 5 art.
  6. 60 How the Moral Virtues Differ from One Another 5 art.
  7. 61 Of the Cardinal Virtues 5 art.
  8. 62 Of the Theological Virtues 4 art.
  9. 63 Of the Cause of Virtues 4 art.
  10. 64 Of the Mean of Virtue 4 art.
  11. 65 Of the Connection of Virtues 5 art.
  12. 66 Of Equality Among the Virtues 6 art.
  13. 67 Of the Duration of Virtues After This Life 6 art.
  14. 68 Of the Gifts 8 art.
  15. 69 Of the Beatitudes 4 art.
  16. 70 Of the Fruits of the Holy Ghost 4 art.
Vice and Sin qq. 71–89
  1. 71 Of Vice and Sin Considered in Themselves 6 art.
  2. 72 Of the Distinction of Sins 9 art.
  3. 73 Of the Comparison of One Sin with Another 10 art.
  4. 74 Of the Subject of Sin 10 art.
  5. 75 Of the Causes of Sin, in General 4 art.
  6. 76 Of the Causes of Sin, in Particular 4 art.
  7. 77 Of the Cause of Sin, on the Part of the Sensitive Appetite 8 art.
  8. 78 Of That Cause of Sin Which Is Malice 4 art.
  9. 79 Of the External Causes of Sin 4 art.
  10. 80 Of the Cause of Sin, As Regards the Devil 4 art.
  11. 81 Of the Cause of Sin, on the Part of Man 5 art.
  12. 82 Of Original Sin, As to Its Essence 4 art.
  13. 83 Of the Subject of Original Sin 4 art.
  14. 84 Of the Cause of Sin, in Respect of One Sin Being the Cause of Another 4 art.
  15. 85 Of the Effects of Sin, and, First, of the Corruption of the Good of Nature 6 art.
  16. 86 Of the Stain of Sin 2 art.
  17. 87 Of the Debt of Punishment 8 art.
  18. 88 Of Venial and Mortal Sin 6 art.
  19. 89 Of Venial Sin in Itself 6 art.
Law qq. 90–108
  1. 90 Of the Essence of Law 4 art.
  2. 91 Of the Various Kinds of Law 6 art.
  3. 92 Of the Effects of Law 2 art.
  4. 93 Of the Eternal Law 6 art.
  5. 94 Of the Natural Law 6 art.
  6. 95 Of Human Law 4 art.
  7. 96 Of the Power of Human Law 6 art.
  8. 97 Of Change in Laws 4 art.
  9. 98 Of the Old Law 6 art.
  10. 99 Of the Precepts of the Old Law 6 art.
  11. 100 Of the Moral Precepts of the Old Law 12 art.
  12. 101 Of the Ceremonial Precepts in Themselves 4 art.
  13. 102 Of the Causes of the Ceremonial Precepts 6 art.
  14. 103 Of the Duration of the Ceremonial Precepts 4 art.
  15. 104 Of the Judicial Precepts 4 art.
  16. 105 Of the Reason for the Judicial Precepts 4 art.
  17. 106 Of the Law of the Gospel, Called the New Law, Considered in Itself 4 art.
  18. 107 Of the New Law As Compared with the Old 4 art.
  19. 108 Of Those Things That Are Contained in the New Law 4 art.
Grace qq. 109–114
  1. 109 Of the Necessity of Grace 10 art.
  2. 110 Of the Grace of God as Regards Its Essence 4 art.
  3. 111 Of the Division of Grace 5 art.
  4. 112 Of the Cause of Grace 5 art.
  5. 113 Of the Effects of Grace 10 art.
  6. 114 Of Merit 10 art.
Secunda Secundae 189 questions · 917 articles

Second Part of the Second Part

The same journey in particular: faith, hope and charity, the four cardinal virtues, and the ways of life.

Faith qq. 1–16
  1. 1 Of Faith 10 art.
  2. 2 Of the Act of Faith 10 art.
  3. 3 Of the Outward Act of Faith 2 art.
  4. 4 Of the Virtue Itself of Faith 8 art.
  5. 5 Of Those Who Have Faith 4 art.
  6. 6 Of the Cause of Faith 2 art.
  7. 7 Of the Effects of Faith 2 art.
  8. 8 Of the Gift of Understanding 8 art.
  9. 9 Of the Gift of Knowledge 4 art.
  10. 10 Of Unbelief in General 12 art.
  11. 11 Of Heresy 4 art.
  12. 12 Of Apostasy 2 art.
  13. 13 Of the Sin of Blasphemy, in General 4 art.
  14. 14 Of Blasphemy Against the Holy Ghost 4 art.
  15. 15 Of the Vices Opposed to Knowledge and Understanding 3 art.
  16. 16 Of the Precepts of Faith, Knowledge, and Understanding 2 art.
Hope qq. 17–22
  1. 17 Of Hope, Considered in Itself 8 art.
  2. 18 Of the Subject of Hope 4 art.
  3. 19 Of the Gift of Fear 12 art.
  4. 20 Of Despair 4 art.
  5. 21 Of Presumption 4 art.
  6. 22 Of the Precepts Relating to Hope and Fear 2 art.
Charity qq. 23–46
  1. 23 Of Charity, Considered in Itself 8 art.
  2. 24 Of the Subject of Charity 12 art.
  3. 25 Of the Object of Charity 12 art.
  4. 26 Of the Order of Charity 13 art.
  5. 27 Of the Principal Act of Charity, Which Is to Love 8 art.
  6. 28 Of Joy 4 art.
  7. 29 Of Peace 4 art.
  8. 30 Of Mercy 4 art.
  9. 31 Of Beneficence 4 art.
  10. 32 Of Almsdeeds 10 art.
  11. 33 Of Fraternal Correction 8 art.
  12. 34 Of Hatred 6 art.
  13. 35 Of Sloth 4 art.
  14. 36 Of Envy 4 art.
  15. 37 Of Discord, Which Is Contrary to Peace 2 art.
  16. 38 Of Contention 2 art.
  17. 39 Of Schism 4 art.
  18. 40 Of War 4 art.
  19. 41 Of Strife 2 art.
  20. 42 Of Sedition 2 art.
  21. 43 Of Scandal 8 art.
  22. 44 Of the Precepts of Charity 8 art.
  23. 45 Of the Gift of Wisdom 6 art.
  24. 46 Of Folly Which Is Opposed to Wisdom 3 art.
Prudence qq. 47–56
  1. 47 Of Prudence Considered in Itself 16 art.
  2. 48 Of the Parts of Prudence 1 art.
  3. 49 Of Each Quasi-integral Part of Prudence 8 art.
  4. 50 Of the Subjective Parts of Prudence 4 art.
  5. 51 Of the Virtues Which Are Connected with Prudence 4 art.
  6. 52 Of the Gift of Counsel 4 art.
  7. 53 Of Imprudence 6 art.
  8. 54 Of Negligence 3 art.
  9. 55 Of Vices Opposed to Prudence by Way of Resemblance 8 art.
  10. 56 Of the Precepts Relating to Prudence 2 art.
Justice qq. 57–122
  1. 57 Of Right 4 art.
  2. 58 Of Justice 12 art.
  3. 59 Of Injustice 4 art.
  4. 60 Of Judgment 6 art.
  5. 61 Of the Parts of Justice 4 art.
  6. 62 Of Restitution 8 art.
  7. 63 Of Respect of Persons 4 art.
  8. 64 Of Murder 8 art.
  9. 65 Of Injuries Committed on the Person 4 art.
  10. 66 Of Theft and Robbery 9 art.
  11. 67 Of the Injustice of a Judge, in Judging 4 art.
  12. 68 Of Matters Concerning Unjust Accusation 4 art.
  13. 69 Of Sins Committed Against Justice on the Part of the Defendant 4 art.
  14. 70 Of Injustice with Regard to the Person of the Witness 4 art.
  15. 71 Of Injustice in Judgment on the Part of Counsel 4 art.
  16. 72 Of Reviling 4 art.
  17. 73 Of Backbiting 4 art.
  18. 74 Of Tale-Bearing 2 art.
  19. 75 Of Derision 2 art.
  20. 76 Of Cursing 4 art.
  21. 77 Of Cheating, Which Is Committed in Buying and Selling 4 art.
  22. 78 Of the Sin of Usury 4 art.
  23. 79 Of the Quasi-integral Parts of Justice 4 art.
  24. 80 Of the Potential Parts of Justice 1 art.
  25. 81 Of Religion 8 art.
  26. 82 Of Devotion 4 art.
  27. 83 Of Prayer 17 art.
  28. 84 Of Adoration 3 art.
  29. 85 Of Sacrifice 4 art.
  30. 86 Of Oblations and First-fruits 4 art.
  31. 87 Of Tithes 4 art.
  32. 88 Of Vows 12 art.
  33. 89 Of Oaths 10 art.
  34. 90 Of the Taking of God's Name by Way of Adjuration 3 art.
  35. 91 Of Taking the Divine Name for the Purpose of Invoking It by Means of Praise 2 art.
  36. 92 Of Superstition 2 art.
  37. 93 Of Superstition Consisting in Undue Worship of the True God 2 art.
  38. 94 Of Idolatry 4 art.
  39. 95 Of Superstition in Divinations 8 art.
  40. 96 Of Superstition in Observances 4 art.
  41. 97 Of the Temptation of God 4 art.
  42. 98 Of Perjury 4 art.
  43. 99 Of Sacrilege 4 art.
  44. 100 On Simony 6 art.
  45. 101 Of Piety 4 art.
  46. 102 Of Observance, Considered in Itself, and of Its Parts 3 art.
  47. 103 Of Dulia 4 art.
  48. 104 Of Obedience 6 art.
  49. 105 Of Disobedience 2 art.
  50. 106 Of Thankfulness or Gratitude 6 art.
  51. 107 Of Ingratitude 4 art.
  52. 108 Of Vengeance 4 art.
  53. 109 Of Truth 4 art.
  54. 110 Of the Vices Opposed to Truth, and First of Lying 4 art.
  55. 111 Of Dissimulation and Hypocrisy 4 art.
  56. 112 Of Boasting 2 art.
  57. 113 Of Irony 2 art.
  58. 114 Of the Friendliness Which Is Called Affability 2 art.
  59. 115 Of Flattery 2 art.
  60. 116 Of Quarreling 2 art.
  61. 117 Of Liberality 6 art.
  62. 118 Of the Vices Opposed to Liberality, and in the First Place, of Covetousness 8 art.
  63. 119 Of Prodigality 3 art.
  64. 120 Of "Epikeia" or Equity 2 art.
  65. 121 Of Piety 2 art.
  66. 122 Of the Precepts of Justice 6 art.
Fortitude qq. 123–140
  1. 123 Of Fortitude 12 art.
  2. 124 Of Martyrdom 5 art.
  3. 125 Of Fear 4 art.
  4. 126 Of Fearlessness 2 art.
  5. 127 Of Daring 2 art.
  6. 128 Of the Parts of Fortitude 1 art.
  7. 129 Of Magnanimity 8 art.
  8. 130 Of Presumption 2 art.
  9. 131 Of Ambition 2 art.
  10. 132 Of Vainglory 5 art.
  11. 133 Of Pusillanimity 2 art.
  12. 134 Of Magnificence 4 art.
  13. 135 Of Meanness 2 art.
  14. 136 Of Patience 5 art.
  15. 137 Of Perseverance 4 art.
  16. 138 Of the Vices Opposed to Perseverance 2 art.
  17. 139 Of the Gift of Fortitude 2 art.
  18. 140 Of the Precepts of Fortitude 2 art.
Temperance qq. 141–170
  1. 141 Of Temperance 8 art.
  2. 142 Of the Vices Opposed to Temperance 4 art.
  3. 143 Of the Parts of Temperance, in General 1 art.
  4. 144 Of Shamefacedness 4 art.
  5. 145 Of Honesty 4 art.
  6. 146 Of Abstinence 2 art.
  7. 147 Of Fasting 8 art.
  8. 148 Of Gluttony 6 art.
  9. 149 Of Sobriety 4 art.
  10. 150 Of Drunkenness 4 art.
  11. 151 Of Chastity 4 art.
  12. 152 Of Virginity 5 art.
  13. 153 Of Lust 5 art.
  14. 154 Of the Parts of Lust 12 art.
  15. 155 Of Continence 4 art.
  16. 156 Of Incontinence 4 art.
  17. 157 Of Clemency and Meekness 4 art.
  18. 158 Of Anger 8 art.
  19. 159 Of Cruelty 2 art.
  20. 160 Of Modesty 2 art.
  21. 161 Of Humility 6 art.
  22. 162 Of Pride 8 art.
  23. 163 Of the First Man's Sin 4 art.
  24. 164 Of the Punishments of the First Man's Sin 2 art.
  25. 165 Of Our First Parents' Temptation 2 art.
  26. 166 Of Studiousness 2 art.
  27. 167 Of Curiosity 2 art.
  28. 168 Of Modesty as Consisting in the Outward Movements of the Body 4 art.
  29. 169 Of Modesty in the Outward Apparel 2 art.
  30. 170 Of the Precepts of Temperance 2 art.
Prophecy and the Charisms qq. 171–178
  1. 171 Of Prophecy 6 art.
  2. 172 Of the Cause of Prophecy 6 art.
  3. 173 Of the Manner in Which Prophetic Knowledge Is Conveyed 4 art.
  4. 174 Of the Division of Prophecy 6 art.
  5. 175 Of Rapture 6 art.
  6. 176 Of the Grace of Tongues 2 art.
  7. 177 Of the Gratuitous Grace Consisting in Words 2 art.
  8. 178 Of the Grace of Miracles 2 art.
The Active and Contemplative Life qq. 179–182
  1. 179 Of the Division of Life into Active and Contemplative 2 art.
  2. 180 Of the Contemplative Life 8 art.
  3. 181 Of the Active Life 4 art.
  4. 182 Of the Active Life in Comparison with the Contemplative Life 4 art.
States of Life qq. 183–189
  1. 183 Of Man's Various Duties and States in General 4 art.
  2. 184 Of the State of Perfection in General 8 art.
  3. 185 Of Things Pertaining to the Episcopal State 8 art.
  4. 186 Of Those Things in Which the Religious State Properly Consists 10 art.
  5. 187 Of Those Things That Are Competent to Religious 6 art.
  6. 188 Of the Different Kinds of Religious Life 8 art.
  7. 189 Of the Entrance into Religious Life 10 art.
Tertia Pars 90 questions · 549 articles

Third Part

Christ, the way back to God: the Incarnation, His life, death and rising, and the sacraments. Left unfinished.

The Incarnation qq. 1–26
  1. 1 Of the Fitness of the Incarnation 6 art.
  2. 2 Of the Mode of Union of the Word Incarnate 12 art.
  3. 3 Of the Mode of Union on the Part of the Person Assuming 8 art.
  4. 4 Of the Mode of Union on the Part of the Human Nature 6 art.
  5. 5 Of the Parts of Human Nature Which Were Assumed 4 art.
  6. 6 Of the Order of Assumption 6 art.
  7. 7 Of the Grace of Christ as an Individual Man 13 art.
  8. 8 Of the Grace of Christ as He Is the Head of the Church 8 art.
  9. 9 Of Christ's Knowledge in General 4 art.
  10. 10 Of the Beatific Knowledge of Christ's Soul 4 art.
  11. 11 Of the Knowledge Imprinted or Infused on the Soul of Christ 6 art.
  12. 12 Of the Acquired or Empiric Knowledge of Christ's Soul 4 art.
  13. 13 Of the Power of Christ's Soul 4 art.
  14. 14 Of the Defects of Body Assumed by the Son of God 4 art.
  15. 15 Of the Defects of Soul Assumed by Christ 10 art.
  16. 16 Of Those Things Which Are Applicable to Christ in His Being and Becoming 12 art.
  17. 17 Of Christ's Unity of Being 2 art.
  18. 18 Of Christ's Unity of Will 6 art.
  19. 19 Of the Unity of Christ's Operation 4 art.
  20. 20 Of Christ's Subjection to the Father 2 art.
  21. 21 Of Christ's Prayer 4 art.
  22. 22 Of the Priesthood of Christ 6 art.
  23. 23 Of Adoption as Befitting to Christ 4 art.
  24. 24 Of the Predestination of Christ 4 art.
  25. 25 Of the Adoration of Christ 6 art.
  26. 26 Of Christ as Called the Mediator of God and Man 2 art.
The Life of Christ qq. 27–59
  1. 27 Of the Sanctification of the Blessed Virgin 6 art.
  2. 28 Of the Virginity of the Mother of God 4 art.
  3. 29 Of the Espousals of the Mother of God 2 art.
  4. 30 Of the Annunciation of the Blessed Virgin 4 art.
  5. 31 Of the Matter From Which the Saviour's Body Was Conceived 8 art.
  6. 32 Of the Active Principle in Christ's Conception 4 art.
  7. 33 Of the Mode and Order of Christ's Conception 4 art.
  8. 34 Of the Perfection of the Child Conceived 4 art.
  9. 35 Of Christ's Nativity 8 art.
  10. 36 Of the Manifestation of the Newly Born Christ 8 art.
  11. 37 Of Christ's Circumcision, and of the Other Legal Observances Accomplished in Regard to the Child Christ 4 art.
  12. 38 Of the Baptism of John 6 art.
  13. 39 Of the Baptizing of Christ 8 art.
  14. 40 Of Christ's Manner of Life 4 art.
  15. 41 Of Christ's Temptation 4 art.
  16. 42 Of Christ's Doctrine 4 art.
  17. 43 Of the Miracles Worked by Christ, in General 4 art.
  18. 44 Of Christ's Miracles Considered Specifically 4 art.
  19. 45 Of Christ's Transfiguration 4 art.
  20. 46 The Passion of Christ 12 art.
  21. 47 Of the Efficient Cause of Christ's Passion 6 art.
  22. 48 Of the Efficiency of Christ's Passion 6 art.
  23. 49 Of the Effects of Christ's Passion 6 art.
  24. 50 Of the Death of Christ 6 art.
  25. 51 Of Christ's Burial 4 art.
  26. 52 Of Christ's Descent into Hell 8 art.
  27. 53 Of Christ's Resurrection 4 art.
  28. 54 Of the Quality of Christ Rising Again 4 art.
  29. 55 Of the Manifestation of the Resurrection 6 art.
  30. 56 Of the Causality of Christ's Resurrection 2 art.
  31. 57 Of the Ascension of Christ 6 art.
  32. 58 Of Christ's Sitting at the Right Hand of the Father 4 art.
  33. 59 Of Christ's Judiciary Power 6 art.
The Sacraments qq. 60–65
  1. 60 What Is a Sacrament? 8 art.
  2. 61 Of the Necessity of the Sacraments 4 art.
  3. 62 Of the Sacraments' Principal Effect, Which Is Grace 6 art.
  4. 63 Of the Other Effect of the Sacraments, Which Is a Character 6 art.
  5. 64 Of the Causes of the Sacraments 10 art.
  6. 65 Of the Number of the Sacraments 4 art.
Baptism and Confirmation qq. 66–72
  1. 66 Of the Sacrament of Baptism 12 art.
  2. 67 Of the Ministers by Whom the Sacrament of Baptism Is Conferred 8 art.
  3. 68 Of Those Who Receive Baptism 12 art.
  4. 69 Of the Effects of Baptism 10 art.
  5. 70 Of Circumcision 4 art.
  6. 71 Of the Preparations That Accompany Baptism 4 art.
  7. 72 Of the Sacrament of Confirmation 12 art.
The Eucharist qq. 73–83
  1. 73 Of the Sacrament of the Eucharist 6 art.
  2. 74 Of the Matter of This Sacrament 8 art.
  3. 75 Of the Change of Bread and Wine into the Body and Blood of Christ 8 art.
  4. 76 Of the Way in Which Christ Is in This Sacrament 8 art.
  5. 77 Of the Accidents Which Remain in This Sacrament 8 art.
  6. 78 Of the Form of This Sacrament 6 art.
  7. 79 Of the Effects of This Sacrament 8 art.
  8. 80 Of the Use or Receiving of This Sacrament in General 12 art.
  9. 81 Of the Use Which Christ Made of This Sacrament at Its Institution 4 art.
  10. 82 Of the Minister of This Sacrament 10 art.
  11. 83 Of the Rite of This Sacrament 6 art.
Penance qq. 84–90
  1. 84 Of the Sacrament of Penance 10 art.
  2. 85 Of Penance as a Virtue 6 art.
  3. 86 Of the Effect of Penance, As Regards the Pardon of Mortal Sin 6 art.
  4. 87 Of the Remission of Venial Sin 4 art.
  5. 88 Of the Return of Sins Which Have Been Taken Away by Penance 4 art.
  6. 89 Of the Recovery of Virtue by Means of Penance 6 art.
  7. 90 Of the Parts of Penance, in General 4 art.

Read with a guide

Commentaries on the Summa worth your time.

No one should read the Summa alone. These are the companions, old and new, that we think are worth it.

Read beside the text

Modern companions that make the Summa approachable without watering it down.

  • A Summa of the Summa Peter Kreeft · 1990

    The best way in. Kreeft selects the essential philosophical articles and footnotes them line by line, explaining terms as they come up.

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  • Practical Theology: Spiritual Direction from Saint Thomas Aquinas Peter Kreeft · 2014

    358 short passages chosen for prayer and daily life, each with a page of reflection. The Summa as spiritual reading.

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  • A Companion to the Summa Walter Farrell, O.P. · 1938–1942

    Four volumes that retell the whole Summa, part by part, in plain and lively English. A Dominican classic for lay readers.

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  • Aquinas: A Beginner's Guide Edward Feser · 2009

    A clear, rigorous introduction to the metaphysics behind the Five Ways, the soul and natural law.

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  • Thomas Aquinas's Summa Theologiae: A Guide and Commentary Brian Davies, O.P. · 2014

    Walks through the whole Summa in order, question by question. The best single-volume commentary on all of it.

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The man and his world

To understand the Summa, it helps to understand who wrote it, and why.

  • Saint Thomas Aquinas: “The Dumb Ox” G. K. Chesterton · 1933

    Not a commentary but a portrait, and the most enjoyable book ever written about Thomas. Étienne Gilson, the great historian of Thomism, judged it the best book ever written on him.

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  • Guide to Thomas Aquinas Josef Pieper · 1962

    A short, luminous account of Thomas's life and the thirteenth-century university he wrote for.

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  • Aquinas's Summa: Background, Structure, and Reception Jean-Pierre Torrell, O.P. · 2005

    How the Summa was written, how it is built, and how it has been read since. Short and scholarly.

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The classic commentators

For the serious student: the commentaries the tradition itself has relied on.

  • Commentaria in Summam Theologiam Cardinal Cajetan (Tommaso de Vio) · early 1500s

    The great commentary, article by article. Pope Leo XIII had it printed beside the text in the Leonine edition. Latin, and in the public domain.

    Leonine volumes on Internet Archive ↗
  • Reality: A Synthesis of Thomistic Thought Réginald Garrigou-Lagrange, O.P. · 1946; English 1950

    The twentieth century's great Thomist (and teacher of St John Paul II) sums up the whole of Thomas's thought in one book.

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Questions

About the Summa Theologiae.

What is the Summa Theologiae?

The Summa Theologiae (“summary of theology”) is St Thomas Aquinas's great work, written between about 1265 and 1273 as a guide for beginners in theology. It covers God, creation, the human person, happiness, virtue, law, grace, Christ and the sacraments in 512 questions and 2,669 articles. Thomas stopped writing in December 1273, partway through the Third Part.

Who was St Thomas Aquinas?

A Dominican friar, priest and theologian, born at Roccasecca in the Kingdom of Naples in 1225 (some say 1227), who taught in Paris, Rome and Naples. He died at the Cistercian abbey of Fossanova on 7 March 1274, was canonized by Pope John XXII in 1323, and was proclaimed a Doctor of the Church by St Pius V in 1567. He is called the Angelic Doctor.

Where should I start reading the Summa?

Start with the Prologue, where Thomas says he wrote it for beginners, then the first article (I, q. 1, a. 1) and the Five Ways (I, q. 2, a. 3). After that, follow your curiosity: the opening of the Second Part on happiness (I-II, qq. 1-5) is one of the most readable stretches of the whole work.

How do I read an article of the Summa?

Every article asks a yes-or-no question, then gives the objections (the case against Thomas's view), a “sed contra” (an authority on the other side), Thomas's own answer (“I answer that”), and a reply to each objection. A good habit for a first pass is to read the question, then the answer, then go back to the objections and replies.

What are the Five Ways?

Thomas's five arguments that God exists, in the Summa Theologiae I, q. 2, a. 3. They argue from motion, from efficient causes, from possibility and necessity, from the gradation of things (more and less good, true and noble), and from the governance of the world, where things without intelligence act for an end.

Why is the Summa unfinished?

On 6 December 1273, after a long ecstasy during Mass, Thomas laid aside his pen. When his companion Reginald of Piperno urged him to go on, he answered that he could do no more, because what had been revealed to him made all he had written seem of little value. He died three months later. The Third Part breaks off in the questions on Penance, at question 90.

Is the Summa free to read online?

Yes. Every question and article is here, free and without an account: the Latin of the Leonine edition beside the 1920 English translation of the English Dominican Fathers, searchable by title or by reference.

Which translation and Latin text is this?

The English is the translation by the Fathers of the English Dominican Province (second, revised edition, 1920), the standard English version for a century and in the public domain. The Latin is the Leonine edition (Rome, 1888-1906), the critical text commissioned by Pope Leo XIII, as transcribed by the Corpus Thomisticum.

Is the Supplement included?

Not yet. The Supplement, which completes the Third Part, was put together after Thomas's death from his earlier commentary on the Sentences of Peter Lombard. Who compiled it is uncertain: it is often credited to his companion Reginald of Piperno, and by others to Peter of Auvergne or Henry of Gorkum. This explorer covers what Thomas wrote for the Summa itself.

About the text

The Latin is the Leonine edition (Rome, 1888–1906), the critical text commissioned by Pope Leo XIII, as transcribed by the Corpus Thomisticum (Enrique Alarcón, University of Navarre), to whom every reader of Thomas online owes a debt.

The English is the translation by the Fathers of the English Dominican Province (Benziger Brothers, second and revised edition, 1920), in the public domain, from the Project Gutenberg edition prepared by Sandra K. Perry and David McClamrock. We have aligned the two part by part, so each objection, answer and reply sits beside its original. Where the two editions divide a passage differently, both are kept whole.

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