This scene marks the change in the play from a simple detective story to psychological drama. From now on, the problem of the play will be not only who killed Laius, but also what can people know of one another and themselves, and how can they know it.
Despite his rejection of Tiresias, Oedipus does believe in the power of prophecy, as he confesses to Jocasta. Oedipus recalls two disturbing revelations—one from an oracle, the other from a drunken man—that make him doubt himself. Note that the drunken man’s railings complement and confirm the oracle’s message about Oedipus’ fate. At the Festival of Dionysus—the god of wine—such a telling detail would be regarded as a tribute.
Jocasta, in contrast to Oedipus, rejects the power of prophecy, citing as proof her own experience with the oracle who predicted that her son would kill her husband. But as she takes Oedipus through a rational explanation of why the prophecy turned out to be false, she unexpectedly jogs his memory. Paradoxically, then, Jocasta’s skepticism brings Oedipus to the suspicion that perhaps the prophet is right after all—and that he is the murderer of Laius.
