''But I don't want to go among mad people'', Alice remarked.
''Oh, you can't help that'', said the Cat: ''we are all mad here. I'm mad. You're mad.''
''How do you know I'm mad?'' said Alice.
''You must be'', said the Cat, ''or you wouldn't have come here.''
-Alice's Adventures In Wonderland
Chapter VI, Pig and Pepper