Cheshire Cat
"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."
"And how do you know that you're mad?"
"To begin with," said the Cat, "a dog's not mad. You grant that?"
"I suppose so," Alice said.
"Well, then," the Cat went on, "you see a dog growl when it's angry, and wag 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."
"I call it purring, not growling," said Alice.
( O )