Joseph Campbell:
The Sphinx in the Oedipus story is not the Egyptian Sphinx, but a female form with the wings of a bird, the body of an animal, and the breast, neck, and face of a woman. What she represents is the destiny of all life. She has sent a plague over the land, and to life the plague, the hero has to answer the riddle that she presents: "What is it that walks on four legs, then on two legs, and then on three?" The answer is "Man." The child creeps about on four legs, the adult walks on two, and the aged walk with a cane.
The riddle of the Sphinx is the image of life itself through time--childhood, maturity, age, and death. When without fear you have faced and accepted the riddle of the Sphinx, death has no further hold on you, and the curse of the Sphinx disappears. The conquest of the fear of death is the recovery of life's joy.
(The Power of Myth, 151-152)
Hubris: This is the Greek notion concerning arrogance from pride or passion -- a human being not knowing his or her place as a mere human being.