Catharsis is the the effect of' purgation' or 'purification' achieved by tragic drama, according to Aristotle's argument in his Poetics. Aristotle wrote that a TRAGEDY should succeed 'in arousing pity and fear in such a way as to accomplish a catharsis of such emotions'. There has been much dispute about his meaning, but Aristotle seems to be rejecting Plato's hostile view of poetry as an unhealthy emotional stimulant. His metaphor of emotional cleansing has been read as a solution to the puzzle of audiences' pleasure or relief in witnessing the disturbing events enacted in tragedies. Another interpretation is that it is the PROTAGONIST'S guilt that is purged, rather than the audience's feeling of terror. Adjective: cathartic.
Accordingly, Aristotle says that the tragic hero will most effectively evoke both our pity and terror if he is neither thoroughly good nor thoroughly bad but a mixture of both; and also that this tragic effect will be stronger if the hero is "better than we are," in the sense that he is of higher than ordinary moral worth. Such a man is exhibited as suffering a change in fortune from happiness to misery because of his mistaken choice of an action, to which he is led by his hamartia—his "error of judgment" or, as it is often though less literally translated, his tragic flaw. (One common form of hamartia in Greek tragedies was hubris, that "pride" or overweening self-confidence which leads a protagonist to disregard a divine warning or to violate an important moral law.)
The tragic hero, like Oedipus in Sophocles' Oedipus the King, moves us to pity because, since he is not an evil man, his misfortune is greater than he deserves; but he moves us also to fear, because we recognize similar possibilities of error in our own lesser and fallible selves. Aristotle grounds his analysis of "the very structure and incidents of the play" on the same principle; the plot, he says, which will most effectively evoke "tragic pity and fear" is one in which the events develop through complication to a catastrophe in which there occurs (often by an anagnorisis, or discovery of facts hitherto unknown to the hero) a sudden peripeteia, or reversal in his fortune from happiness to disaster.