The intellectual most frequently forced to turn in his grave is...

Kurt Gödel, by far. His incompleteness theorem is definitely the most abused piece of formal reasoning ever written. (By "most abused" I mean "invoked as implying the most non-mathematical consequences absurdly far-removed from the domain in which it has any applicability.") I've read and/or heard in conversations, arguments which quite seriously purported Gödel's theorem to imply (in no particular order): postmodernism, creationism, existence of God, non-existence of God, "inevitability of human condition" (I'm not joking), computability of human intelligence, non-computability of human intelligence, impossibility of complete knowledge of mathematics, impossibility of complete knowledge of anything, existence of immaterial soul, non-existence of pretty much anything... etc., etc.

I don't know what it is about this particular bit of knowledge that elicits so much crackpottery.