COMMENTARY ON THE NICOMACHEAN ETHICS
by
Thomas Aquinas

translated by
C. I. Litzinger, O.P.

Chicago: Henry Regnery Company, 1964, 2 volumes

OUTLINE INDEX OF THE TEN BOOKS OF THE ETHICS (nos. 1-2180)

BOOK I:	THE GOOD FOR MAN	Aristotle
Summary:	The difference of ends.
	Happiness, the end and supreme good of the happy person.
	The two parts of the soul.
	Division of virtue.
Lecture 1.	The subject matter of moral philosophy.	1094
	Its end and the diversity of ends.
Lecture 2.	Human affairs have an end, a supreme end.	1094 a 19
	A knowledge of this end is necessary.
	This knowledge belongs to the most important science, political science.
Lecture 3.	What disposition the student and the teacher of this science should have.	1094 b 13
	Neither a youth nor a slave of the emotions is a reliable student.
Lecture 4.	Opinions about happiness.
	How the philosopher and the ordinary man differ about the supreme good.	1095 a 15
	Happiness itself, a supreme good.
	The disposition of the student.
Lecture 5.	What opinion about happiness is more probable.	1095 b 12
	An error of the common people.
	Happiness and virtue.
Lecture 6.	Happiness in a separated good.	1096 a 12
	The existence of this good.
Lecture 7.	The separated good as an absolute good.	1096 a 34
	How the Platonists and the Pythagoreans agree concerning the good.
Lecture 8.	Even if a separated good exists, an investigation would be out of order.	1096 b 29
	This matter belongs to another science.
Lecture 9.	An inquiry into the nature of happiness.	1097 a 16
	Happiness is the ultimate end.
	The conditions for an ultimate end.
Lecture 10.	The definition of happiness.	1097 b 22
	Its genus and differences.
	The activity proper to man, an operation of reason.
Lecture 11.	What still remains to be done.	1098 a 22
	Time as a help and an obstacle to the discovery of truth.
Lecture 12.	Confirmation of the definition of happiness.	1098 b 9
	The testimony of other philosophers.
	The credibility of things generally accepted about happiness.
Lecture 13.	Pleasure’s contribution to happiness.	1099 a 9
	Pleasure in virtuous action.
	Happiness in virtue together with pleasure.
	External goods as necessary to happiness.
Lecture 14.	Is the cause of happiness divine, human, or fortuitous?	1099 b 9
Lecture 15.	Whether anyone can be called happy in this life.	1100 a 5
	The view of Solon.
	Can the dead be called happy?
Lecture 16.	Happiness and unhappiness by reason of the goods of fortune.	1100 b 8
	Good and bad are not judged by goods of fortune.
	The virtuous and happy man bears all turns of fortune.
Lecture 17.	How the fortune of friends affects happiness.	1101 a 22
	The misfortunes of friends cannot really change the condition of the dead.
Lecture 18.	Is happiness one of the goods deserving honor?	1101 b 10
	Happiness, something perfect and best.
	Confirmation by both human and divine praises and by the opinion of Eudoxus.
Lecture 19.	A knowledge of virtue is useful for happiness.	1102 a 4
	This science studies virtue.
	Our science studies and treats certain parts of the soul.
Lecture 20.	Division of the irrational soul into vegetative and sensitive.	1102 a 33
	The vegetative part is not proper to the human soul; does not participate in reason.
	The sensitive part participates in reason.
BOOK II:	MORAL VIRTUE IN GENERAL
Summary	Virtue in general.
	Its essence.
	Mean between extremes.
	Opposition between vice and virtue.
	Directions for acquiring the mean.
Lecture 1.	Virtue a product of habit, not of nature.
	Man becomes virtuous by repeated acts.
Lecture 2.	Operations producing the habit of virtue take place according to right reason.	1103 b 27
	These operations kept intact by the mean.
	Comparison of bodily powers and operations with the virtues and operations of the soul.
Lecture 3.	Pleasure or sorrow a sign of virtue already produced.	1104 b 6
	Proof from the inclination of man intent on virtue; from a penalty called the remedy of the soul; from what is destructive of virtue.
Lecture 4.	Virtues not to be compared with art.	1105 a 18
	Virtues are principles of action.
	Works done by art possess what belongs to the perfection of art.
Lecture 5.	Passions, powers and habits as principles for finding the definition of virtue.	1105 b 20
	Virtues belong to the genus of habit.
Lecture 6.	What kind of habit virtue is.	1106 a 16
	General qualities of virtue.
	Specific difference shown from the characteristic of its operations and from the nature of virtue itself.
Lecture 7.	Virtue defined.	1106 b 29
	Its chief characteristic is the mean.
	Excess and defect happen according to the extremes.
	Evil, according to the Pythagoreans, is unlimited.
	How virtue can be an extreme.
Lecture 8.	Definition of virtue explained.	1107 a 28
	The mean is good but the extreme vicious.
	A discussion of individual virtues and vices.
Lecture 9.	Mean and extreme in virtues relating to honors.	1107 b 23
	Virtues and vices established in the mean and in the extremes.
	Extension of the doctrine to certain passions.
Lecture 10.	Opposition among the virtues and vices.
	Opposition of vices among themselves is greater than of the vices to the virtues.
	One extreme is more opposed to virtue than the other.
Lecture 11.	The manner of acquiring virtue.
	Three ways of acquiring virtue: avoid extremes, consider one’s natural inclinations, and beware of pleasures.
BOOK III:	THE VOLUNTARY, FORTITUDE AND TEMPERANCE
Summary	The voluntary and the involuntary.
	Things consequent to the voluntary.
	Fortitude and temperance.
	Their species and extremes.
Lecture 1.	The involuntary and spontaneous action.	1109 b 30
	The nature of the involuntary resulting from force, from ignorance.
Lecture 2.	Voluntary actions merit praise and condemnation, honor and punishment.	1110 a 19
	Actions done out of fear deserve not praise but pardon.
Lecture 3.	Investigation of the involuntary resulting from ignorance.	1110 b 18
	Differences regarding this ignorance.
Lecture 4.	Definition of the voluntary.	1111 a 22
	Its principle is within the agent knowing the circumstances.
Lecture 5.	A treatise on choice.	1111 b 6
	Choice is neither sensual desire, nor anger.
	How choice differs from wishing.
Lecture 6.	Choice is not identical with opinion.	1111 b 31
	Explanation of what choice is.
Lecture 7.	Counsel is investigated.	1112 a 19
	Certain things are excluded as objects of counsel.
Lecture 8.	Counsel concerns means to an end.	1112 b 13
	The method and order of taking counsel.
Lecture 9.	Counsel in relation to choice.	1113 a 3
	How they are alike; how one precedes the other.
Lecture 10.	The object of willing.	1113 a 15
	Different opinions about this.
Lecture 11.	Virtue and vice are within our power.	1113 b 3
	Confirmation of this truth.
Lecture 12.	That no one is voluntarily evil is rejected.	1114 a 3
	Habits are voluntary in their formation.
Lecture 13.	The opinion that we have no faculty cognoscitive of good is refuted.	1114 a 32
	An objection against our position.
Lecture 14.	Treatise on fortitude.	1115 a 7
	A mean between rashness and fear.
	Principally concerned about fear of death.
Lecture 15.	Objects of fear are not equally terrifying to all.	1115 b 7
	The brave man does not forsake reason be cause of fear.
Lecture 16.	The fortitude of the citizen, of the soldier.	1116 a 16
	A comparison between the two.
Lecture 17.	A counterfeit fortitude operating through rage.	1116 b 23
	Fortitude operating through hope, through ignorance.
Lecture 18.	The properties of fortitude.	1117 a 29
	It rightly orders man in regard to terrifying things.
	Fortitude in relation to pain and pleasure.
Lecture 19.	Treatise on temperance.	1117 b 22
	Not concerned with pleasures of the soul.
Lecture 20.	Temperance and intemperance deal directly with pleasures of touch.	1118 a 26
	Common and proper desires as matter of temperance.
Lecture 21.	How the temperate and intemperate are affected by sorrows, pleasure and pain.	1118 b 29
	Insensibility is not in keeping with human nature.
	The temperate man follows the golden mean in pleasure.
Lecture 22.	Intemperance more voluntary than cowardice.	1119 a 21
	Comparison between intemperance and the vices of children.
BOOK IV:	OTHER MORAL VIRTUES
Summary	Liberality, magnificence, magnanimity, desire of moderate honors, meekness, affability, veracity, pleasantness, shame.
	Their opposites.
Lecture 1.	Liberality, a mean.	1119 b 21
	Extravagance and illiberality, extremes.
Lecture 2.	The nature of the principal act of liberality.	1120 a 23
	Circumstances and qualities of the act.
Lecture 3.	The spendthrift.	1120 b 25
	His act.
	Comparison with the liberal man.
Lecture 4.	Gravity of extravagance.	1121 a 16
	More serious than illiberality.
Lecture 5.	Incurableness of illiberality.	1121 b 14
	Old age favors it.
	Nature inclines to it.
Lecture 6.	Investigation of magnificence.	1122 a 19
	A comparison with liberality.
Lecture 7.	Object of expenditure by the munificent man.	1122 b 19
	Vices contrary to magnificence.
Lecture 8.	A consideration of magnanimity.	1123 a 33
	Its matter.
	Magnanimity in relation to other virtues.
Lecture 9.	Acts of magnanimity.	1124 a 4
	Concerned with honors and riches.
Lecture 10.	Traits of the magnanimous person.	1124 b 6
	Those dealing with matters of other virtues.
	Those in accord with the disposition of the magnanimous person.
Lecture 11.	Vices opposed to magnanimity.	1125 a 16
	Small-mindedness, the defect.
	Presumption, the excess.
Lecture 12.	The virtue concerned with ordinary honors.	1125 b
	Compared to magnanimity, as liberality to magnificence.
	Its mean and its extremes.
Lecture 13.	Meekness and its opposed vices.	1125 b 26
	Concerned with anger.
	Difficult to know how and when to be angry.
Lecture 14.	Excess and defect of pleasantness.	1126 b 10
	The mean and its properties.
Lecture 15.	Veracity.	1127 a 13
	Lying, boasting, and dissembling, the opposite vices.
Lecture 16.	Amusement, a virtue and a vice.	1127 b 33
	How this virtue differs from the virtues treated immediately before.
Lecture 17.	Shame, a passion.	1128 b 10
	Commendable in youths. Similar to continence.
BOOK V:	JUSTICE
Summary	Justice and injustice.
	Their species.
	Equity.
	Justice in the metaphorical sense.
Lecture 1.	Actions treated by justice and injustice.	1129
	The kind of mean justice is.
	Between what extremes justice is the mean.
Lecture 2.	The legally just thing.	1129 b 12
	Legal justice.
Lecture 3.	Particular justice.	1130 a 14
	Particular injustice.
Lecture 4.	Distributive and commutative justice.	1130 b 30
	The mean in these divisions of justice.
Lecture 5.	The just thing and proportionality.	1131 a 30
	Nature of proportionality.
	Proportionality in distributive justice.
Lecture 6.	Commutative justice.	1131 b 25
	Its characteristics.
Lecture 7.	The mean of commutative justice.	1132 a 25
	How determined in like things, in diverse things.
Lecture 8.	The opinion of Pythagoras concerning the mean.	1132 b 21
	Refutation of this opinion.
Lecture 9.	Observance of proportionality in practice.	1133 a 18
	The function of money.
Lecture 10.	How just action is a mean.	1133 b 30
	Justice itself as a mean.
Lecture 11.	Who is truly called unjust.	1134 a 16
	Different ways of being unjust.
Lecture 12.	Division of political justice.	1134 b 18
	Explanation of its parts.
Lecture 13.	The role of voluntariness in determining the just thing and the just man.	1135 a 15
	How ignorance, passion, and choice affect justice.
Lecture 14.	To suffer injustice is an involuntary.	1136 a 10
	To inflict injustice is a voluntary.
Lecture 15.	Who is unjust in distributions.	1136 b 15
	Refutation of certain errors.
Lecture 16.	Equity.
	Its object, subject, and habit.
Lecture 17.	Justice in the metaphorical sense.	1137 a 31
	No injustice done to oneself.	1138 a 4
BOOK VI:	INTELLECTUAL VIRTUES
Summary	Principles of operation.
	Intellectual habits: science, art, understanding, wisdom, and prudence.
	Connection between prudence and other virtues.
Lecture 1.	Right reason.	1138 b 18
	Division of the parts of the soul.
Lecture 2.	Principles of human acts.	1139 a 15
	Function proper to the intellect.
Lecture 3.	Enumeration of the intellectual virtues.	1139 b 14
	Habit of science.
	Definition of art.
Lecture 4.	Explanation of prudence: who is prudent, what is prudence.	1140 a 24
	Prudence differs from art.
Lecture 5.	Understanding, a virtue concerned with the principles of demonstration.	1140 b 31
	Wisdom understood in two ways.
Lecture 6.	Wisdom, the principal virtue absolutely speaking.	1141 a 19
	Difference between wisdom and prudence.
Lecture 7.	Prudence the principal virtue concerned with human affairs.	1141 b 22
	Prudence and the art of government.
	Prudence compared with understanding.
Lecture 8.	Virtues annexed to prudence.	1142 a 32
	Eubulia, its definition and conditions.
Lecture 9.	Synesis, what it is not.	1142 b 34
	Gnome compared with synesis.
	Synesis and gnome compared with prudence.
Lecture 10.	Doubts about the utility of wisdom and prudence.	1143 b 17
	Solution of the doubts.
Lecture 11.	No moral virtue without prudence.	1144 b
	Prudence does not rule wisdom.
BOOK VII:	CONTINENCE AND INCONTINENCE
Summary	Continence and attitudes opposed to continence.
	The continent and the incontinent man.
	Pleasure and its species. Pain.
Lecture 1.	Censurable moral dispositions; contrary dispositions.	1145 a 15
Lecture 2.	Difficulties concerning continence.	1145 b 22
	Doing what one knows is evil.
Lecture 3.	Solutions of the difficulties.	1146 b 8
	Difference between the continent and the incontinent.
Lecture 4.	Pleasure and pain, the material for continence and incontinence.	1147 b 20
Lecture 5.	Natural pleasures; pleasures against nature.	1148 b 15
	How these are treated by continence and incontinence.
Lecture 6.	Comparison between incontinence of anger and of pleasure, between animal incontinence and human incontinence.	1149 a 24
Lecture 7.	Agreement of continence with perseverance.	1150 a 9
	Different kinds of incontinence.
Lecture 8.	The intemperate are worse than the incontinent.	1150 b 29
	The repentance of the incontinent.
Lecture 9.	Who is really continent, who obstinate.	1151 a 29
	Comparison between continence and temperance.
Lecture 10.	No man is simultaneously prudent and incontinent.	1152 a 7
	Comparison of the incontinent with the prudent man.
Lecture 11.	Pleasure and pain, the concern of the statesman.	1152 b 25
	Opinions against the goodness of pleasure.
Lecture 12.	Refutation of the opinions.	1152 b 25
	Different kinds of good.
Lecture 13.	The evil Of pain.	1153 b
	The greatest pleasure is happiness.
Lecture 14.	Pleasures of the body.	1154 a 8
	To what extent they are good and necessary
BOOK VIII:	FRIENDSHIP
Summary	Friendship and its various kinds.
	Diverse matters concerning friends and friendship.
Lecture 1.	Virtue, the foundation of friendship.	1155
	Discussion of friendship belongs to moral philosophy.
Lecture 2.	Good, the object of friendship.	1155 b 17
	Definition of friendship.
Lecture 3.	Kinds of friendship.	1156 a 5
	Friendships for utility and for pleasure.
	Their difference from perfect friendship.
Lecture 4.	Comparison between useful and pleasant friendships.	1157
Lecture 5.	The acts and habit of friendship.	1157 b 5
	How they differ.
Lecture 6.	Multiplicity of friends.	1158 a 3
	Infrequency of perfect friendship.
	Comparison between kinds of friends.
Lecture 7.	Friendship between unequals.	1158 b ii
	Various kinds of this friendship.
	Their preservation.
Lecture 8.	Loving is a property of friendship.	1159 a 13
	Preservation of friendship by love.
	Friendship between opposites.
Lecture 9.	Friendships following on association.	1159 b 25
	Diversification of associations.
	Political association as a foundation of friendship.
Lecture 10.	Distinction of political associations.	1160 a 30
	Similarity of political and domestic associations.
Lecture 11.	Kinds of friendship correspond to kinds of political order, both good and bad.	1161 a 10
Lecture 12.	Subdivisions of friendship.	1161 b 11
	Friendship among relatives; its properties.
	Friendship between husband and wife.
Lecture 13.	Avoidance of complaints in friendship.	1162 a 34
	Complaints in utilitarian friendship between equals.
Lecture 14.	Complaints in friendship of utility between unequals.	1163 a 24
BOOK IX:	PROPERTIES OF FRIENDSHIP
Summary	Preservation of friendship.
	The works of friendship: goodwill, concord, beneficence, love of self.
	Friends of a happy man; the number of friends.
	Need for friends.
Lecture 1.	Properties pertaining to the preservation of friendship.	1163 b 30
	Remedies against disturbance of friendship.
Lecture 2.	Doubts on the duties of friendship.	1164 b 28
	Helping one’s parents, friends, and benefactors.
Lecture 3.	Minor doubts on the dissolution of friendship.	1165 a 37
	Friendship and change of status.
Lecture 4.	Origin of friendships’ acts.	1166 a
	Enumeration of these acts.
	The relations of good and bad men to the acts of friendship.
Lecture 5.	Goodwill is not friendship, but is the beginning of friendship.	1166 b 30
Lecture 6.	Concord.	1167 a 21
	Its relation to friendship.
	Its subject matter.
	Where found.
Lecture 7.	Beneficence.	1167 b 21
	Love between benefactor and beneficiary.
Lecture 8.	Love of self.	1168 a 28
	Censurable in one sense.
Lecture 9.	A virtuous man’s love of self.	1168 b 29
	Laudable in one sense.
Lecture 10.	A happy man’s love of others.	1169 b 3
	His need of friends.
Lecture 11.	Fundamental reason why a virtuous man needs friends.	1170 a 13
Lecture 12.	Limitation on the number of friends.
	Needed especially in virtuous friendship.
Lecture 13.	Need for friends in adversity and prosperity; most of all in adversity.	1171 a 21
Lecture 14.	Pleasure in the companionship of friends.	1171 b 29
	Influence of friends on one another.
BOOK X:	PLEASURE. HAPPINESS
Summary	Pleasure; its kinds.
	Happiness, contemplative and active.
	Preparation for and connection with the treatise on the state.
Lecture 1	Pleasure, a subject of moral philosophy.	1172 a 19
	Three reasons for its treatment.
Lecture 2.	Pleasure as a good.	1172 b 9
	Eudoxus’ opinion.
	Plato’s objection to this opinion.
Lecture 3.	Pleasure is not a kind of good according to Plato.	1173 a 14
	His arguments and their refutation.
Lecture 4.	A fourth argument of the Platonists and its refutation.	1173 b 21
Lecture 5.	Pleasure is not a motion or a process of change.	1174 a 13
	It is similar to the act of seeing.
Lecture 6.	Pleasure is a perfection of activity.	1174 b 14
	Its duration; its desirability.
Lecture 7.	Difference among pleasures according to their activities.	1175 a 22
Lecture 8.	Pleasures are good or bad both morally and physically.	1175 b 25
Lecture 9.	Happiness, the end of human activity.	1176 a 30
	Nature of happiness.
Lecture 10.	Happiness is in accordance with the highest virtue.	1177 a 12
	This is contemplation.
Lecture 11.	Happiness and leisure.	1177 b 4
	The nature of leisure.
Lecture 12.	Another kind of happiness.	1178 a 9
	Produced by the moral virtues.
Lecture 13.	Happiness and external goods.	1178 b 33
	Great wealth not needed for happiness.
Lecture 14.	The role of habit in virtuous living; legislation is also required.	1179 a 33
Lecture 15.	Man must be a legislator,	1180 a 25
	Supervision and instruction are necessary.
Lecture 16.	How to become a legislator.	1180 b 28
	The difference between politics and the other arts.