Does the Exception really prove the rule?

Question

And if so, when doesn't it?

Answer 1

Despite the famous quote to the contrary, exceptions do not prove rules.  Ever.  Exceptions always disprove rules.  And it only takes one exception to disprove a rule.

For example, when Newton published his "Principia", it provided a system of rules that explained every physical phenomenon that we had witnessed at that time.  It did not explain the perihelion procession of Mercury's orbit, which we had not observed yet.  When we finally did observe this odd-behaving orbit, the world's scientists did not declare to the world that Mercury was the exception that proved Newton right.  Instead, they realized that Newton was wrong, and the entire theory needed to be reworked.  Einstein was able to develop a new theory that explained everything that Newton's theory explained as well as all the phenomenon that Newton's theory could not explain, but as Einstein himself once said "No amount of experimentation can ever prove me right; a single experiment can prove me wrong."

And before anyone asks, no, there is no exception to the rule that there are no exceptions to rules.

Answer 2

Too vague, bad question.

Answer 3

Depending on what you're talking about, yes.  The original latin phrase, "exceptio probat regulam," has undergone so much misinterpretation and misapplication that it's hard to really talk about it without confusion.

The late Ambrose Bierce used to lead an argument that the phrase in English basically means the exception puts the rule to the proof (i.e., requires it to be proven).  Historical evidence is actually contrary to that idea, and in fact I don't think the phrase was ever meant philosophically at all.  Exceptio probat regulam was originally used in Roman legal documents for legal purposes.  For example, if a government figure decrees that soldiers going to battle the next day are allowed to stay out past 9 p.m., that decree can be used as proof of the rule that soldiers in general cannot stay out past 9 p.m.

Answer 4

"And before anyone asks, no, there is no exception to the rule that there are no exceptions to rules."

d**n it!