Thomas Aquinas

Catholic philosopher and theologian

Medieval influential 134 sayings

Sayings by Thomas Aquinas

It is permissible to kill a thief if he cannot otherwise be resisted.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 64, Art. 7
Controversial Unverifiable

The purpose of human law is to lead men to virtue, not suddenly, but gradually.

c. 1265-1274 — Summa Theologica, Part I-II, Q. 96, Art. 2
Controversial Unverifiable

A thing is just when it is proportionate to another according to some equality.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 57, Art. 1
Controversial Unverifiable

The root of all evil is avarice.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 118, Art. 1
Controversial Unverifiable

Man is by nature a social animal.

c. 1269-1272 — Commentary on Aristotle's Politics, Book I, Lecture 1
Controversial Unverifiable

The greatest evil is to do wrong and not to suffer for it.

c. 1265-1274 — Often attributed, but exact source in Aquinas is difficult to pinpoint. Reflects his general ethical…
Controversial Unverifiable

It is necessary for the good of the community that criminals should be put to death.

c. 1259-1265 — Summa Contra Gentiles, Book III, Chapter 146
Controversial Unverifiable

The state has the right to coerce its citizens for the common good.

c. 1265-1267 — De Regimine Principum, Book I, Chapter 15
Controversial Unverifiable

It is not lawful for a man to have more than one wife at a time.

c. 1259-1265 — Summa Contra Gentiles, Book III, Chapter 123
Controversial Unverifiable

The natural order of things requires that women be subject to men.

c. 1265-1274 — Summa Theologica, Part I, Q. 92, Art. 1
Controversial Unverifiable

Slavery is a consequence of sin, and thus it is just.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 57, Art. 3, Reply Obj. 2
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The purpose of marriage is the procreation of children.

c. 1265-1274 — Summa Theologica, Part III, Supplement, Q. 49, Art. 1
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Usury is a sin against justice.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 78, Art. 1
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The truth of faith is made manifest by the Holy Spirit, not by human reason.

c. 1265-1274 — Summa Theologica, Part I, Q. 1, Art. 8
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It is not lawful to lie in order to save anyone from death.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 110, Art. 3
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The proper object of the human intellect is the quiddity or essence of a material thing.

c. 1265-1274 — Summa Theologica, Part I, Q. 84, Art. 7
Controversial Unverifiable

The order of charity is that a man should love God first, then himself, then his neighbor.

c. 1265-1274 — Summa Theologica, Part II-II, Q. 26, Art. 4
Controversial Unverifiable

The primary cause of sin is the will.

c. 1265-1274 — Summa Theologica, Part I-II, Q. 75, Art. 1
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Ignorance is the cause of all evil.

c. 1265-1274 — Often attributed, but a more precise phrasing in Aquinas is that ignorance can be a cause of sin, no…
Controversial Unverifiable

The natural law is nothing else than the rational creature's participation in the eternal law.

c. 1265-1274 — Summa Theologica, Part I-II, Q. 91, Art. 2
Controversial Unverifiable