The tragic fall of Oedipus in Sophocles play "Oedipus Rex" is both self-inflicted and result of events drawn from his own destiny. First off early on in Oedipus' life his first deadly mistake towards succeeding his self-inflicted downfall was the murder of his father the former king. In a blind rage without any motive, he kills Liaus and his men at a rode crossing. Fate may have had led him to that point but it was his own rage that resulted in his biggest mistake. Further evidence of his self-inflicted downfall Oedipus' was at the hands of his own ignorance. This ignorance combined with his stubborn, determined attitude does not allow him foresight.
This foresight would have led to some restraint in his decision and rash actions. Such an example would be his blatant ignoring of Teriesas's ub tle clues as to why he holds his tongue, "It is because I see your words, sir, tending / To no good end; therefore I guard my own. Nevertheless Oedipus's elf-assurance leads Oedipus to believe that the evidence presented before him by the blind prophet Teriesas is utter nonsense and turns the blame instead upon him. This ignorance is not clear to Oedipus as he is still riding his magnificent riddle solution he conjured to save the city. However, his hastiness is later replaced by his insecurity and self-doubt during the anagnorisis when the light is shed on his lacking investigative skills.
In addition to this ever so apparent rashness Oedipus then over steps even his own bounds by heading up the investigation solely. Before gathering even gathering any witness or evidence Oedipus is quick to draw not only conclusions as to newfound suspect status, but worse develops a wicked connection between two very unlikely suspects, "Have you the face to stand before my door / Proved plotter against my life, thief of my crown?" [pg 40]. Creon then tries to warn Oedipus about his condemning, "To slur a good man's name / With baseless slander is one crime-another / Is rashly to mistake bad men for good. /Cast out an honest friend, and you cast out / Your life, your dearest treasure". [pg 42]. As Creon tries to convince him to go about things in a more timely, and sensible way Oedipus hears none of it and still pursues his march of getting to the bottom laying the blame elsewhere all along the way.
As Creon and Teriesas both note suggestions to Oedipus' involvement he still pursues further investigation without the littlest consideration at his own guilt. This lack of foresight, and understanding again is another cause to Oedipus's elf-inflicted downfall. However, there are many factors that contribute his downfall that he could not have prevented and were truly acts of fate and destiny. His self-assurance to his wisdom that was bred by his "mother-wit and not by bird-lore" (as he takes a stab at Teriesas pg 37) really comes to surface during his encounter with a riddling Sphinx. This inflated view of his wisdom later leads to his downfall. But it was only by fate that he ignorant Oedipus was awarded a IQ freebie from the Sphinx.
By answering his riddle he stepped onto the path towards his soon to be place on the Theban throne. In addition to the Sphinx, the adoption of Oedipus when he was young and abandoned into the house of Polypus was too only a synergist factor in his rise to Kingship. Had he been born and raised by the Shepard who found him, then his status would have refrained him heavily from succession his father. This too was an act of fate, and at the tender age of only a few weeks, Oedipus had no say into the events that were to come. Furthermore the decision by the parents to cast him away, and not to kill him gave an opportune window to Oedipus to carry out the later events that were to come. Jocasta notes that " [Oedipus] was not 3 days old when [Lau is] cast it out with riveted ankles / To perish on the empty mountain-side". [pg 45].
This decision to first, not have the job done themselves and two, not done properly was the only reason that the baby survived and became what he was. In addition fate again played a vital role in the Oedipus' demise. Particularly his father's murder was at the hands of Liaus himself through his decisions. His father's decision (to cast him away) was based on an oracle he had received earlier in his kingship that foretold Oedipus would, .".. become the parent of a misbegotten brood / An offence to all mankind and kill [his] father". [pg 47]. When informed of this, Oedipus fled from Cornish, to the place where he would eventually kill his father. In conclusion, Oedipus' tragic demise was a carefully planned out combination of both his own self-infliction and two, as the Greeks would say, at the hands of the Gods.