Oscar Levant? Zsa Zsa Gabor? John Dryden? Colin Wilson? Apocryphal? Question for Quote Investigator: A self-deprecating comedian once delivered an acerbic remark about insanity. Here are two versions: (1) There is a thin line between genius and insanity. I have erased that line.(2) There is a fine line between sanity and insanity. I’ve managed to …