Why can Oedipus solve the riddle of the Sphynx fairly quickly but cannot solve the riddle of his own existence? Why do you think Tiresias is unable to solve the riddle of the Sphynx but knows who Oedipus “really” is? What is there about the nature of the riddle (“What walks on four legs in the morning, two in the afternoon and three in the evening?”) that makes it easier to answer than the riddle of one’s own existence? What does this conundrum say about human existence?