“‘In that direction,’ the Cat said, waving its right paw round, ‘lives a Hatter: and in that direction,’ waving the other paw, ‘lives a March Hare. Visit either you like: they’re both mad.’
‘But I don’t want to go among mad people,’ Alice remarked.
‘Oh, you can’t help that,’ said the Cat: ‘we’re 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” by Lewis Carroll