Yossarian: Is Orr crazy?
Doc: Of course he is. He has to be crazy to keep flying after all his close calls he's had.
Yossarian: Why can't you ground him?
Doc: I can, but he has to ask me.
Yossarian: That's all he's gottta do to be grounded?
Doc: That's all.
Yossarian: Then you can ground him?
Doc: No. Then I cannot ground him.
Yossarian: Aha!
Doc: There's a catch.
Yossarian: A catch?
Doc: Sure. Catch 22. Anyone who want's to get out of combat isn't really crazy. so I can't ground him.
Yossarian: Ok, let me see if I've got it straight. In order to be grounded, I've got to be crazy. And I must be crazy to keep flying. But if I ask to be grounded, that means I'm not crazy anymore, and I have to keep flying.
Doc: You got it, that's Catch 22.
Yossarian: That's some catch, that Catch 22.
Doc: It's the best there is.