Exceptio probat regulam in casibus non exceptis
“The exception confirms the rule in cases not excepted.”
Legal maxim (after Cicero, Pro Balbo)
What does “Exceptio probat regulam in casibus non exceptis” mean?
Exceptio probat regulam in casibus non exceptis translates as “The exception confirms the rule in cases not excepted.”
Stating an exception for some cases implies that the rule applies to all other cases.
“Exceptio probat regulam in casibus non exceptis” word by word
| Latin | English | Grammar |
|---|---|---|
| Exceptio | the exception | nominative singular feminine (subject) of exceptio, “an exception, a taking-out” |
| probat | proves, confirms | 3rd person singular present indicative active of probo, “I test, approve, prove” |
| regulam | the rule | accusative singular (direct object) of regula, “rule” |
| in casibus | in cases | ablative plural of casus, “case, instance”, after the preposition in |
| non exceptis | not excepted | ablative plural of the perfect passive participle of excipio, “I take out, except”, negated by non; agrees with casibus |
How to pronounce “Exceptio probat regulam in casibus non exceptis”
Classical exceptio has a hard c (ek-SKEP-tee-oh). Church Latin softens the c before e and i, and tio sounds like tsee-oh. Stress falls on the third syllable of exceptio, the first of probat, the second of regulam and the first of casibus.
The story behind it
Word for word the maxim says that an exception proves the rule in cases that are not excepted. It is a legal principle, not a general remark about life.
It sums up an argument Cicero makes in his speech Pro Balbo of 56 BC. If a law or rule names certain exceptions, that very act of naming shows the rule holds in every case left unnamed.
The maxim is the source of the English saying “the exception proves the rule”. Here “proves” keeps its older sense of “tests” or “confirms”, which is why the saying is so often misread.
How to use “Exceptio probat regulam in casibus non exceptis”
It suits a legal or debating context, an essay on how rules and exceptions work, or a caption for someone who enjoys the quirks of law and language. As a tattoo or motto it is a niche, witty choice for lawyers and logicians.
- Latin
- Exceptio probat regulam in casibus non exceptis
- English
- The exception confirms the rule in cases not excepted.
- Source
- Legal maxim (after Cicero, Pro Balbo)
- Era
- Antiquity
- Theme
- Justice
Common mistakes
- It does not mean that an exception shows a rule to be true. It means a named exception confirms the rule for all other cases.
- Cutting it down to “Exceptio probat regulam” drops the closing qualifier, in casibus non exceptis, which carries the actual legal meaning.
- Probat here means “confirms, establishes”, not “proves” in the modern sense of demonstrating by evidence.
- It is a later legal maxim built on Cicero’s argument, not a sentence Cicero wrote in this form.
Questions about “Exceptio probat regulam in casibus non exceptis”
What does “Exceptio probat regulam in casibus non exceptis” mean literally?
“The exception proves the rule in cases not excepted.” It says that stating an exception confirms the rule for every case not named.
Who said “Exceptio probat regulam”?
It is a legal maxim that sums up an argument from Cicero’s speech Pro Balbo (56 BC). The wording in this form is later and has no single known author.
Is “the exception proves the rule” a logical mistake?
Not originally. “Proves” meant “tests” or “confirms”, and the point is that a named exception implies the rule applies everywhere else.
How do you pronounce “Exceptio probat regulam”?
In Classical Latin: ek-SKEP-tee-oh PROH-baht reh-GOO-lahm. In Church Latin: eh-CHEP-tsee-oh PROH-baht reh-GOO-lahm.
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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