leading part in the play" (Aristotle 670). Sophocles introduced the third actor and scenery. And tragedy acquired its magnitude by expanding its scope and increasing the dignity of its presentation. The playwrights proceeded by discarding the trochaic meter, more appropriate to dancing, for the iambic which was more like natural speech. The number of scenes was increased as well, allowing for the representation of more complicated actions. Overall tragedy followed a course of development that fitted it for the expression of important themes. In Aristotle's definition tragedy was "the imitation of an action that is serious and also, as having magnitude, complete in itself; in language with pleasurable accessories, each kind brought in separately in the parts of the work; in a dramatic, not in a narrative form; with incidents arousing pity and fear, wherewith to accomplish its catharsis of such emotions" (Aristotle 672).
For Aristotle drama was essentially imitative because the initial impulse to create poetry, of which drama was one branch, derives from two natural human characteristics: the desire to imitate and delight in imitation. Human beings are the most imitative of all creatures and "learn at first by imitation" (Aristotle 668). It is therefore natural for them to create imitations in the various forms found in the arts. Human beings also delight in works of imitation because the observation of any work of imitation is a form of learning and "to be learning something is the greatest of pleasures not only to the philosopher but also to the rest of mankind, however small their capacity for it" (Aristotle 668-69).
The more serious poets took the course of representing actions that were serious and involved noble personages. Of the various elements of tragedy Plot, "the combination of the incidents, or things done in the story," was the most important because it was through action, especially through peripeties and ...