Tragedy As Catharsis:

"But Justice turns the balance scales, sees that we suffer and we suffer and we learn.  And we will know the future when it comes."
                                                                                             -- Chorus, Agamemnon, Aeschylus

The greatest minds in history have grappled with, and disagreed about, the value of tragedy to the human experience.  The only thing they agree upon is that it is of great value.

Catharsis is a medical term referring to purging or cleansing, and both Plato and Aristotle argued witnessing tragic theater grants the audience this experience.

Plato argued catharsis separated the soul from the body/senses -- and we should consider how all great art does this: it removes us from reality and takes us temporarily into another imaginative, emotional realm; for Plato, this realm may be "truer" than physical reality.

Aristotle argued witnessing tragic drama simply forces us to temporarily experience the dangers of transgression and teaches us a basic cautionary tale at a deep, truly terrifying emotional level. It is one thing to tell you not to trust your wife and another to take you through the experience of witnessing Agamemnon's tragic fall. 

Others interpret Aristotle's treatment of catharsis to mean that we leave the theater feeling emotionally spent -- the pity and terror of our real lives has been released in theater, placed on a scape-goat (remember goat-song?) and successfully "dealt with" for awhile.

Wisdom is central to Aristotle's view of tragedy and the tragic hero's experience: the tragic experience is not meaningless, and its meaning, at the conclusion, is not wasted on the tragic hero;  only the tragic experience itself completes the hero's journey to a deeper understanding of him or herself and the workings of the cosmos.

Aristotle's view forms the modern psychological perspective: Unaddressed fears tend to evolve (descend?) into neurosis and phobia, and in order to maintain sanity we must learn that we can overcome terror (note the origin of Freud and psychoanalysis here).

You might also think about how good you feel after you cry. I mean, that's what I've heard because, you know, being a real man, I never cry....

Mirror neurons: psychologists have increasingly noted that the brain actually fires the neural connections associated with behaviors when we watch those behaviors: in the literal, neural sense, the mind actually "lives" vicariously when we watch sports, and of course pornography, and we literally release love pheromones when we watch lovers fall in love on the screen.  So, the theory here would be that to watch tragedy is to experience tragedy, and thus to learn from the vicarious, artistic experience of suffering.

Nietzsche argued that we enter the tragic not to free ourselves from it but to celebrate it as a necessary element of the human experience:  "The psychology of the orgiastic as an overflowing feeling of life and strength, where even pain still has the effect of a stimulus, gave me the key to the concept of tragic feeling, which had been misunderstood both by Aristotle and even more by modern pessimists... Saying Yes to life even in its strangest and most painful episodes, the will to life rejoicing in its own inexhaustible vitality even as it witnesses the destruction of its greatest heroes — that is what I called Dionysian, that is what I guessed to be the bridge to the psychology of the tragic poet. Not in order to be liberated from terror and pity, not in order to purge oneself of a dangerous affect by its vehement discharge — which is how Aristotle understood tragedy — but in order to celebrate oneself the eternal joy of becoming, beyond all terror and pity — that tragic joy included even joy in destruction"