"The exception proves the rule." What exactly does this mean? An example would be nice.?

It's an odd one because it's gone from having a proper meaning to being the "nonsense" referred to above.

The original meaning was what it says: that an exception proves that there is a general (usually unstated) rule for the exception to apply to. Like you said an example will be useful. Say you see a sign saying "No Fishing On Sundays". This is an exception to the general rule Fishing Is Allowed; so you can assume that fishing is fine on any day except Sunday.

If you want to be flash, the expression goes back to Roman Times when a city argued that since new cities had a clause in their charter saying they were not allowed to build temples; their city, which had no such clause in *their* charter was allowed to build a new temple.

"The exception proves the rule" is a saying whose meaning has been interpreted or misinterpreted in various ways. Its true definition, or at least original meaning, is that the presence of an exception applying to a specific case establishes ("proves") that a general rule exists. For example, a sign that says "parking prohibited on Sundays" (the exception) "proves" that parking is allowed on the other six days of the week (the rule). A more explicit phrasing might be "the exception that proves the existence of the rule."

An alternative explanation often encountered is that the word "prove" is used in the archaic sense of "test".[1] Thus, the saying does not mean that an exception demonstrates a rule to be true or to exist, but that it tests the rule. In this sense, it is usually used when an exception to a rule has been identified: for example, Mutillidae are wasps without wings which cannot fly, and therefore are an exception that proves (tests) the rule that wasps fly. The explanation that "proves" really means "tests" is, however, considered false by some sources. .....more.....

https://en.wikipedia.org/wiki/Exception_that_prove...

http://mentalfloss.com/article/52698/how-does-exce...

http://bigthink.com/the-proverbial-skeptic/what-th...

It is derived from the medieval Latin legal principle: exceptio probat regulam in casibus non exceptis (the exception tests the rule in the cases not excepted).

A form of argument in which the existence of a counterexample to a rule is used to demonstrate the fact that a rule exists.

(idiomatic) The rare occurrence of a counterexample to a rule, used to underscore that the rule exists.

Examples

"Entry is free on Sundays."

- This implies that entry is not free on the other six days of the week.

"Parking prohibited on Sundays."

- This implies that parking is not prohibited on the other six days of the week.

https://en.wiktionary.org/wiki/exception_that_prov...

https://dictionary.cambridge.org/dictionary/englis...

This is "prove" in the sense of "test," as in "proving ground."

If there are many exceptions, the rule would be disproved. But if there are few exceptions, the rule can still stand in the great majority of cases.

It's a nonsense expression used when there's no explanation for anomalies in English grammar.

sorry its bullsh** there can be an exception to the rule there often is it is rather an inane statement if I murder some one and break the rule that would be proving the rule was right is a bit basic

It means that if you have something which violates a rule, it has a clear reason for doing so. It is an exception for a reason, which proves that the rule is true.

For an example, let us say that ther eis a rule which says everyone in a certain room must be hopping.

Everyone in the room hops, because thats the rule.

But one person doesn't, violating the rule. So the rule can't be true.

But - special circumstances. The person not hopping has borken their leg, so is unable to hop.

The rule is still true, it just takes into account the special circumstances.