"The exception that proves the rule"

This is not really a thing. Nothing could ever "prove" a rule by virtue of not following it. I don't want to list examples but I will anyway: in this book I'm reading about the NYRB the author talks about how the editors of that publication never discovered any young talent or launched anyone's career. He then lists two people whose careers the NYRB did launch, and refers to them subsequently as "rule-proving exceptions."

This is not how data works, and I say that with some confidence even though I do not know that much about how data works. These two guys are outliers, sure, and you can know that if you know that all the other people who contributed to the NYRB were old and established by the time they started publishing there, but you can't just look at them and extrapolate the "rule" he's insisting they prove. In fact, these two guys don't really make any difference whatsoever, because if you believe the rule is true, the fact that in these two instances it didn't hold teaches you nothing new, and in identifying them as outliers you haven't come upon anything that would/should strengthen your faith in the pattern from which you think they are deviating.

UPDATE: Turns out this is an old, fossilized factoid, not a new thing at all. It has a Wikipedia entry and everything. So humiliating!! Sorry readers, this was some straight to video shit.