Mimesis - Aristotle indicates that the medium of tragedy is drama, not narrative; tragedy “shows” rather than “tells.” According to Aristotle, tragedy is higher and more philosophical than history because history simply relates what
has happened while tragedy dramatizes what
may happen.
The incentive moment - The plot must be “a whole,” with a beginning, middle, and end. The beginning, called by modern critics the ''
incentive moment'' which
must start the cause-and-effect chain but not be dependent on anything outside the compass of the play.
The denouement - Aristotle calls the cause-and-effect chain leading from the incentive moment to the climax the “tying up”, in modern terminology the complication. He therefore terms the more rapid cause-and-effect chain from the climax to the resolution the “unravelling”, in modern terminology the
dénouement.
The deus ex machina - The plot must be “complete,” having “unity of action.” By this Aristotle means that the plot must be structurally self-contained, with the incidents bound together by internal necessity, each action leading inevitably to the next with no outside intervention, no
deus ex machina
Catastrophe - The plot may be either simple or complex, although complex is better. Simple plots have only a “change of fortune” (catastrophe).