I've never understood the logic of the phrase, "the exception that proves the rule." I like green grapes. Update: I've gotten lots of emails explaining that "prove" in this case means "test." Thus, "the exception that tests the rule." Okay, that makes slightly more sense from a logic perspective, but it does not help the phrase make any more sense in advancing arguments that something is a "rule," which is how this phrase is normally used. Anyway, thanks for the sorta clarifications. I still like green grapes. Update update: The straight dope. Yes, that's what I thought.