...
Alice: But I don't want to go among mad people.
The Cat: Oh, you can't help that. We're all mad here. I'm mad. You're mad.
Alice: How do you know I'm mad?
The Cat: You must be. Or you wouldn't have come here.
Alice: And how do you know that you're mad?
The Cat: To begin with, a dog's not mad. You grant that?
Alice: I suppose so,
The Cat: Well, then, 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.
And you don't have to run as fast to get away from the ones that are after you. :)