On Monday we will discuss Aristotle's great contribution to an understanding of Sophocles' Oedipus.

First and most importanr is Aristotle's distinction between simple and complex plots:

"Some plots are simple, others are complex. By "simple" plot, I mean one in which as it develops in a consecutive and unified manner... the shift in fortune (metabasis) comes about without peripety (peripeteia) or recognition; by "complex" one in which the shift (metabasis) is accomplished consecutively but with peripety or recognition or both." (Poetics1452a12ff.)

Next, Aristotle defines peripety:

Peripety is the shift of the action toward the opposite pole..., as, for example, in the Oedipus, the messenger who has arrived, when it seems that he will make Oedipus happy and relieve him of his fears towards his mother by revealing who he is, brings about the oposite." (Poetics, 1452a23ff.)

 What Aristole means will require some explication! He is making an extraordinarily important point, which is often misunderstood.