It means that the existence of an exception is the evidence that the rule exists. It is often used to justify an inconsistency. The original expression derives from a Latin legal principle from the early seventeenth century: 'exceptio probat regulam in casibus non exceptis', which came into common use as 'exceptio probat regulam' - the exception establishes the rule - whose logical meaning was that the exception provides the opportunity to test and refine more accurately the scope of the rule.

Übersetzung:

die Ausnahme, die die Regel bestätigt

Gegenteil(e)

The opposite of "the exception that proves the rule" is "there is no exception of the rule".

Synonym(e):

You could also say: an instance that does not obey a rule shows that the rule exists.