【正文】 d absurd world, there are the beastlike oppressors and the insectlike oppressed men. The later bees the tool of the former to attain their shabby aims. But luckily enough not all the oppressed behave in all insect way. They are san, to a certain extent, and they make full use of their limited freedom in that lunatic situation and stand the responsibility to make another way out of the world for others. In Catch22, Orr and Yossarian have perfectly embodies the thought of existentialism in terms of free choice. OrrOrr, Yossarian’s pixielike roommate, represents the little man who is inconspicuous, longsighted, persevering, and capable of achieving success at impossible odds. Orr always behaves in a funny way as a clown in Catch22: he always puts crab apples in his cheeks which makes his words difficult to be understood。 he has been beaten by a whore over his head with the heel of her shoe for fifteen or twenty minutes once in Rome，but he giggles through it, which makes others pletely puzzled。 Nearly every time he flies a bat mission, He will be shot down. People consider Orr pitiful, so does Yossarian. Yossarian’s such worrying seems rational because Orr has acted ridiculously. But is Orr really a so funny and simpleminded person? He remains enigmatic up to the last chapter. In fact, Orr makes himself look stupid, his funny behavior makes him a look of stupid innocence that nobody would ever think any cleverness of him．The oppressors will not think such a funny soldier would do anything against their control. Orr is the personification of qualifies of intelligence and endurance which make possible the survival of humanity under the worst condition of oppression and exploitation (Milne 184). He banks on the military establishment’s general lack of imagination．He is a doer and admirably equipped to survive. He is pletely awake what he wants, and that is the same thing that ostensibly energizes Yossariansurvival. To achieve it, Orr first pays the whore for being beaten. Then he chooses to do something as a fool and practices being shot down. At last，he goes to the ideal country. His successful escape to Sweden is ‘‘a(chǎn) miracle of human intelligence and human endurance” (458). It convinces Yossarian that escape is possible and leads to his own desertion near the end of the novel. YossarianHeller propagates in this novel the absurdity of the world and the alienation of human beings, and at the same time he suggests the chance of free choice in the absurdity. Such a possibility is well embodied in the aviatorprotagonist Yossarian. Living in all unfavorable circumstance, he resists the irrationality in an absurd way. Heller has description of Yossarian39。s appearance, his family background, let alone his life career. We know little about him except that he is big and strong, and 28 years old. We just can imagine what kind of person he is through our own imagination. Clearly Heller wants us to regard Yossarian as an ordinary man who can be any one of us who may act ridiculously in the absurd world. At the beginning, he is an upright and honest man with a strong feeling of patriotism. On the first missions，he behaved very bravely. For example, when he was on the mission to Ferrara, in order to fulfill his mission he came in carefully on his second bomb run and succeeded (though later Colonel Cathcart regards his second bomb as a “black eye”).Heller himself once was a pilot in the Second World War. He had flown sixty missions during the war. On his thirtyseven mission, one of hisinarms was seriously wounded, and that made Heller dearly realize that he was in great danger (Wang Shouren 152). Heller39。s such experience is well reproduced in the affair of Snowden39。s death.Partly due to Nately39。s whore39。s attack, Snowden’s death, and his horrible experience in the “Eternal City” Rome, Yossarian slowly realizes that he cannot attempt to save his own life at the expense of others’. At last, Yossarian opts for desertion, which endangers him but gives the other men the right kind of moral example．Since using reason in the face of the irrational is futile，the way out of Catch22 is simply to rebel, in Camna’s sense, to take a stand, to say “no” (Kennard 1639). Yossarian shows us his brevity by saying “no” to Colonel Cathcart’s deal, and it is a “no” to the absurd world. His decision to desert is climatic, affirms that successful protest is possible, however hopeless such protest can seem and however painful the immediate consequences may be. As James Draper once mented “although most critics identify Yossarian as a coward and an anti hero, they also sympathize with his urgent need to protect himself from this brutal universal law.” (Draper 1629) Generally speaking, Yossarian is a hero of Black Humor. He is utterly aware of his situation. Not only does he not go along with evil trend, but also not belittle himself. At last he chooses to desert. It is a method of taking his life back into his own hand. His desertion is an openly rejection to a mentality of catch22 and he makes his run for freedom. Yossarian’s desertion is a moral, responsible action because his choice sets a good example to those in an absurd situation. He dose not only because he badly hopes to survive, but also because he does it for others. That is why chaplain and Major Danby support him. So Yossarian’s last desertion informs that whenever we make a choice, we must be responsible not only for ourselves, but for the others. This well embodies the existentialist free choice. 4. The Absurdity of the World The Absolute power of the BureaucracyAt the beginning of catch22, Heller points out directly that “there was one catch...and that was Catch22.” The word “catch” is a pun, meaning a hidden problem or difficulty．Such a catch entitles the bureaucratic members to achieve their grubby purpose by all means, and at the same time it forces the ruled men, the people in lower social position, just to accept death with