What it is: 'Catch-22' is the title of a novel by Joseph Heller published in 1961. The book is a magnificent satire on the insanity of war, set in an American air-force base on a small island off Italy during World War 2. With the death toll rising, the number of bombing missions each airman has to make before he is allowed home-leave rises as well. What seems a bright idea - claiming insanity, and so being sent home - is thwarted by the absurd 'rule' Catch-22. According to this, a man 'would be crazy to fly more missions and sane if he didn't - but if he was sane he had to fly them'. No way out of this: if the airman asks not to fly, he's obviously sane, and therefore is fit to fly.
What it means: The expression'Catch-22' is now used to describe any dilemma from which all ways out are a double-bind, a logical trap, self-defeating - and disagreeable.
Think about it: For the soldier trapped by Catch-22, the only way out is to be genuinely mentally ill, (or killed, of course) and what kind of escape is that? It's a pity that 'Catch-22' is now more associated with non-military double-binds, since the whole point of Heller's book was to highlight the madness of war. In war, the things people say they are fighting to preserve (such as lives, freedom, homes, land) are actually destroyed. In a word, crazy. How can people be persuaded that war doesn't work? For a start, look at war in history and see how what people call 'victory' has meant death, devastation, and the probability of more conflict ahead.