the exception proves the rule
the exception that proves the rule

But sometimes, as the saying goes, the exception proves the rule.

"Well no, but the exception proves the rule."

"The exception proves the rule," Sam said.

Famous draft-dodger Bill Clinton was from Arkansas - showing once again that the exception proves the rule.

(The exception proves the rule - the iconoclastic philosopher of science, Paul Feyerabend, has also observed this methodological prejudice.)

It is sometimes said that the word "proves" means "tests", and that "the exception proves the rule" therefore means something like "an exceptional case can be used to test whether or not a rule is valid".

In this example, saying "the exception proves the rule" is literally incorrect, but it is used to draw attention to the rarity of the exception, and to establish the status of the village prior to the exceptional event.

He also reported that it was a "bi-racial" area where "[t]he light and the dark meet" and that "Generally speaking, the odd numbers, on the east side, are dark, the even numbers light; but the exception proves the rule."

Special leave is given for men to be out of barracks tonight till 11.00 p.m.; "The exception proves the rule" means that this special leave implies a rule requiring men, except when an exception is made, to be in earlier.

The second part of Cicero's phrase, "in casibus non exceptis" or "in cases not excepted," is almost always missing from modern uses of the statement that "the exception proves the rule," which may contribute to frequent confusion and misuse of the phrase.

The first speaker in this example has confused the meaning of the phrase, apparently believing that any exception to any rule "proves" the rule true; in this case, the notion that "the exception proves the rule in cases not excepted" is neither implied nor understood by the speaker.

EXCEPTION, n. A thing which takes the liberty to differ from other things of its class, as an honest man, a truthful woman, etc. "The exception proves the rule" is an expression constantly upon the lips of the ignorant, who parrot it from one another with never a thought of its absurdity.