Comment by dwattttt
Comment by dwattttt 3 days ago
Because the phrase has always bothered me: this means something other than what it's commonly understood to nowadays.
An older use of the word "prove", as in to test, means it says "that's an exception that tests the rule, and finds it is incorrect"
There is an alternate interpretation, that the existence of an explicit exception proves (confirms) the existence of a rule to which an exception can be made.
So the (existence of an) exception proves (the existence of) the rule.