Quote from : Catch-22 Book

Who's they?" He wanted to know. "Who, specifically, do you think is trying to murder you?" "Every one of them," Yossarian told him. "Every one of whom?" "Every one of whom do you think?" "I haven't any idea." "Then how do you know they aren't?" "Because..." Clevinger sputtered, and turned speechless with frustration. Clevinger really thought he was right, but Yossarian had proof, because strangers he didn't know shot at him with cannons every time he flew up into the air to drop bombs on them, and it wasn't funny at all.