Duo cum faciunt idem, non est idem
“When two do the same, it is not the same.”
Proverb after Terence, Adelphoe 823-825
What does “Duo cum faciunt idem, non est idem” mean?
Duo cum faciunt idem, non est idem translates as “When two do the same, it is not the same.”
The same action can mean different things depending on who does it and why.
“Duo cum faciunt idem, non est idem” word by word
| Latin | English | Grammar |
|---|---|---|
| Duo | two (people) | nominative masculine plural of duo, “two”; subject of faciunt |
| cum | when | conjunction (here “when” or “if”) introducing the clause |
| faciunt | they do | third person plural present indicative active of facio, “I do, I make” |
| idem | the same thing | accusative neuter singular of idem, “the same”; object of faciunt |
| non | not | adverb of negation |
| est | it is | third person singular present indicative of sum, “I am” |
| idem | the same | nominative neuter singular of idem, “the same”; complement of est |
How to pronounce “Duo cum faciunt idem, non est idem”
The two differ mainly in faciunt, where classical has a hard k and church Latin a ch sound. In both, idem is stressed on the first syllable and faciunt on the second-to-last.
The story behind it
Word for word the line says “two when they do the same, it is not the same”. It is a proverb that goes back to Terence’s comedy Adelphoe (“The Brothers”), written in the second century BC.
In the play, two fathers raise their sons in opposite ways, one strict and one indulgent. The line reflects the idea that identical actions can deserve different judgment depending on the person and their intention.
The wording in the proverb is a later, condensed form of Terence’s lines rather than a quotation word for word. Today it is used whenever someone points out that fairness requires looking at who acts and why, not only at what is done.
How to use “Duo cum faciunt idem, non est idem”
Fits an essay or speech about fairness, double standards or intention, and works as a thoughtful caption or desk motto. As a tattoo it suits someone who values context over snap judgments.
- Latin
- Duo cum faciunt idem, non est idem
- English
- When two do the same, it is not the same.
- Source
- Proverb after Terence, Adelphoe 823-825
- Era
- Classical
- Theme
- Wisdom
Common mistakes
- It does not mean that two people can never do the same thing. It says the same act can carry a different meaning or deserve a different verdict.
- The second idem is not an object but the complement of est, which is why it is not repeated in the same form as a verb would suggest. Do not change either word without checking the case.
- Quoting it as a line spoken word for word by Terence is not accurate. It is a proverb that condenses his lines in Adelphoe.
Questions about “Duo cum faciunt idem, non est idem”
What does “Duo cum faciunt idem, non est idem” mean literally?
“When two do the same, it is not the same.” The same action can differ in meaning depending on who does it.
Who said “Duo cum faciunt idem, non est idem”?
It is a proverb based on Terence’s comedy Adelphoe (around lines 823-825). The short wording is a later condensation of his lines.
How do you pronounce “Duo cum faciunt idem, non est idem”?
In classical Latin: DOO-oh koom FAH-kee-oont EE-dem nohn est EE-dem. In church Latin faciunt becomes FAH-chee-oont.
Is “Duo cum faciunt idem, non est idem” good for a tattoo?
Yes, it is correct Latin and a well-known proverb. It is a little long, so check the spacing and the repeated idem when it is set in print.
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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