'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 didn't think that proved it at all; however, she went on. 'And howdo you know that you're mad?'

'To bagin with,' said the Cat, 'a dog's not mad. You grant that?'

'I suppose so,' said Alice.

'Well, then,' the Cat wrnt on, 'you see a dog growls when it's angry, and wags its tail when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad'.

Lewis Carroll. Alice In Wonderland