Aristotle's Theory of Tragedy

Tragedy: In terms of Aristotle, tragedy must compose of pity and fear. There are five marks of tragedy, it imitates action, brings pity and fear, displays human image, end in mystery, and it is beautiful. According to Aristotle, tragedy does not tell a story, it shows a story, but is not a narrative. A tragedy creates events after one another in order to describe what is happening or about to happen. He describes as all tragedies are beautiful and that there should not be happy endings.
Hamartia: This word means mistake or lack of insight. In tragedies, this creates a more complex problem. This could also lead to character's having bad actions or eventually characters dying after their mistake.

Ancient Greek Theatre

Katharsis: This word in Greek means purification, getting rid of something. But according to Aristotle, he uses this word is reference to a beautiful metaphor, the feeling of being washed or cleansed. This word can also be described as the releasing of emotions within characters. This helps the characters move on from their emotions and not live in the past. There are many emotions in a tragic story so this action of katharsis is common.

Deus ex machina: This word means "God rules all". Aristotle did not support this idea in his tragic plays because he believes outside factors should not affect the play or the whole story. He wanted to make his scenes real and believable.