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Antigone is a tragedy because, following Aristotle's definition of a tragedy, it imitates an action that has serious consequences. The play is about the ability or inability of a citizen to defy the wishes of the state and to prioritize one's family over the state. There are real issues that have serious consequences. The play also offers a catharsis, or a purging of emotions after first causing feelings of pity and fear. In Antigone, the audience feels pity and fear about Creon's persecution of Antigone, and through these emotions, the audience experiences catharsis.
The hero in Antigone also has tragic flaws that bring about his or her downfall. These flaws are typically a form of hamartia (which means a human flaw), and the hero is not brought down because he or she is evil. Both Antigone and Creon, it could be argued, have flaws that result in their downfall, as they are both stubborn and cannot see the other side of the argument in which they are engaged (about whether or not Antigone has the right to bury her brother, who was deemed a traitor to the state).
In addition, the plot of Antigone involves a reversal, or peripeteia, in which a person is brought down from a high position to a low one. Creon experiences this reversal to a greater extent than Antigone does, and he also experiences anagnorisis, or the recognition that his refusal to let Antigone bury her brother has led to destruction and sorrow.
As with all tragic heroes, both Antigone and her uncle, King Creon, suffer from a tragic flaw. stubborness; hers is stubborn self-righteousness and his is stubborn pride, leading to Antigone's death as well as the deaths of Creon's wife and son, Antigone's fiance. As classic tragic figures, they suffer misfortunes brought on by themselves and from others in their story. Laws in society are important in keeping people from living in chaos and not simply living and acting according to their wills but a leader must not be so stubborn that he fails to act compassionately when he needs to do so. Creon is such a leader; he rules absolutely and as a result, abuses that power by destroying the moral, loyal, and couraeous people around him. Antigone is moved by her loyaly to family and by her integrity. But, because Fate has decreed the House of Thebes doomed since Antigone's father, Oedipus, the plot twists and turns with misunderstandings and the conflict between religion and law, resulting in these four characters' deaths. Unfortunately, this same Fate causes Creon to realize and admit he is wrong too late to change this outcome.