Above all else, tragedy requires the finest appreciation by the writer of cause and effect.
No tragedy can therefore come about when its author fears to question absolutely everything, when he regards any institution, habit or custom as being either everlasting, immutable or inevitable. In the tragic view the need of man to wholly realize himself is the only fixed star, and whatever it is that hedges his nature and lowers it is ripe for attack and examination.
Tragedy and the Common Man (1949)