The exception also declares the rule.

Explanation

An exception is not merely a carve-out; it is an affirmative declaration of the scope and content of the rule from which it departs — by showing what is excluded, it illuminates what is included.

Where this applies

• The exception tells us exactly what the rule covers by showing what it excludes.
• By carving out what's excluded, the exception illuminates what's included.
• The exception is an affirmative declaration of the rule's scope.