I am not English-native and made a slip. But now I see and fully agree with the suggestion. But I am not going to correct it, because I want to keep your comment.

Interesting thinking - define/confirm/prove. In medical terms it should be the same. Exception should disprove the rule, instead of creating some atypical addition to the defined condition.

From a philosophical standpoint - do all exceptions help define the rule? I'd say that exceptions define the boudaries of the rule. That's why they are exceptions - by definition.

How about math?