The basis of tragedy is man's helplessness against disease, war and death; the basis of comedy is man's helplessness against vanity (the vanity of love, greed, lust, power).
Bio: Quintus Curtius Rufus was a Roman historian, writing probably during the reign of the Emperor Claudius or Vespasian. His only surviving work, De Rebus Gestis Alexandri Magni, or Historiae Alexandri Magni, is a biography of Alexander the Great in Latin in ten books, of which the first two are lost, and the remaining eight are incomplete.