Another philosophical issue Oedipus must deal with has to do with truth. Is it better to know the truth about oneself, another person, or anything, if that knowledge is going to make one unhappy? Is it better to live in blissful ignorance? Certainly, Oedipus was a much happier person before he learned he murdered his own father, married his mother, and fathered children with the same woman who bore him. The knowledge that both he and his father "planted their seeds" in the same maternal "soil" is terribly upsetting for Oedipus (and for his mother, who kills herself after learning the truth).
Would it have been better for the truth to remain hidden and thus spare the feelings of Jocasta, Oedipus, and their children? It seems that, for Oedipus at least, the answer is "no." Thebes has fallen victim to a blight on the crops, a decline in birthrate, and so forth, as a result of Laius's murderer having gone unpunished (according to the oracle). In learning the truth, Oedipus effectively solves Thebes' problems. His ruin, then, permits others to live better lives. It would have been personally better for Oedipus, however, had he never learned the truth. The old adage "be careful what you wish for" is certainly true for him in this case.
In Oedipus the King, the character of Oedipus has to face the weight of an overwhelming guilt that dooms him. Philosophically, Oedipus has to deal with the fact that while the actions that led to his guilt and ruination were his own, he had no idea that such a fate would befall him. Events spiraled out of his control, and he was powerless to stop them. Did he deserve such a cruel fate, or was the universe simply indifferent to his happiness?
Although Oedipus complains about his fate loudly and pitifully, he does in fact accept it. He is the murderer who inadvertently cursed Thebes, and he must be banished, by his own edict. Even though destiny has dealt him a terribly unfair hand, he acquiesces to the will of the gods and gives up everything, including his home, family, and throne.