In Aristotle's criticism on the genre of tragedy he argues that a tragic hero must possess a tragic flaw, or a hamartia, that is responsible for his or her undoing. Often this hamartia is shown to be hubris, or arrogance, as the character's belief in their own abilities actually results in their own downfall. This is certainly a fault that Oedipus himself struggles with, as he identifies himself so strongly as the saviour of Thebes that he is blind to the way that he is the cause of the problems in Thebes until it is too late. Oedipus, because of the way that he defeated the sphinx and liberated Thebes, sees himself very strongly as the protector of his people. In his opening speech, the way he introduces himself makes the way he sees himself evident:
Here I am myself--
you all know me, the world knows my fame:
I am Oedipus.
This hubris is something that is presented yet again when Creon brings word from the Oracle about the need to find the killer of Laius, the former king of Thebes. Note how Oedipus presents himself in the following quote:
Now you have me to fight for you, you'll see:
I am the land's avenger by all rights,
and Apollo's champion too.
The way that "me" is emphasised clearly indicates that Oedipus strongly believes in his own ability and power to solve this crime. At every stage, Oedipus presents himself in a way that only testifies to his arrogance and his self-belief that he can solve the problem. Of course, the tremendous dramatic irony of this play is that he is able to solve the problem because he is the problem. The seeds of the downfall of Oedipus lie in his own all-consuming belief in himself and his own abilities.