Aristotle sought to anchor his definitions of literary genres in exemplary works and authors. Of tragedians, he considered Sophocles the best, and his Oedipus Tyrannus ("Oedipus the King") the finest example. That's immediately debatable because great works by two other major tragedians survived (Aeschylus and Euripides). In the case of epics, his thesis was easier for modern readers to accept because only one author's works were widely known to him, those of Homer. According to Aristotle, the lost Homeric mock battle narrative, Margites, is to comic drama as the Iliad and the Odyssey are to tragedy. Note that this suggests genres originate in pairs, each balancing qualities the other excels in with qualities it lacks and its partner has in abundance. When distinguishing between epic and tragedy, he said epic has a multiplicity of plots, each of which is fully developed in the epic's larger scope, but the tragedy is a compressed development of a single plot. Aristotle says epics have a major advantage over tragedy because of their multiplicity of incident, the capacity to enlarge its action to incorporate several series of events which may have happened simultaneously [representing them in narrative series by means of flashbacks, etc.].
Background notes relevant to English 215 ("Critical Methods")--
Aristotle was Plato's student, but his thinking differed so much from his teacher's that he did not succeed Plato as head of the Athenian Academy. Instead, he struck out on his own, eventually serving as the tutor to the son and heir of Philip of Macedon, a boy later known as Alexander the Great. Aristotelian philosophy teaches that knowing material reality can be achieved by properly identifying the essential traits of things and distinguishing things from other things by forming classification schemes based on those traits. The theory's great power is that it can produce useful, independently verifiable categories of analysis--if we all can agree on the epic's essential traits, then we can conduct reasonable scholarly discussions about epics. Since Aristotle also was interested (like his teacher, Plato) in the proper organization of human communities, from the one-family "oikos" (whence "economy") to the city-state of the "polis," he also tried to describe the social functions of literature. This continues to be an important line of study in modern literary theory. One of the method's weakness arises from disagreements about what, if anything, can be called essential from the start ("a priori"), outside some kind of social, political, historical processes that made it. A second weakness, shared by some practitioners of Structuralism (q.v.), is Aristotle's fondness for definition and categorization by "binary oppositions": states which are supposed to be mutually exclusive, such as "live or dead," "on or off," in that you can't be both, but must be one or the other. Many of the oppositions by which he constructed his literary analysis are suspect or simply wrong, at least in our own era (e.g., "comedy or tragedy" has become confused with tragi-comedy and satire). Post-Aristotelian thinking tends to avoid relying upon unexamined binary oppositions and to look backwards, in order to situate literature's traits in the processes which created them, but otherwise we owe a great methodological debt to "The Philosopher," as he was known to medieval readers. To read the complete "Poetics," click here.
After Aristotle: Neo-Aristotelian critics in the Renaissance, like Julius Caesar Scaliger and Lodovico Castelvetro, codified Aristotle's general observations about the need for some kind of unity in a work to create the (needless) aesthetic rule that all great plays must obey the "four unities" of form, time, action, and place. The authority of this early Neo-Aristotelian criticism soon was exploded by the emergence of mixed genres like "tragi-comedy," successful leaps of time between acts of plays or chapters of novels, audience enjoyment of sub-plots and complex plots, and great popularity of travel narratives. Twentieth-Century Neo-Aristotelianism is generally associated with the University of Chicago school of critics, including Elder Olsen, R. S. Crane, and Richard McKeon. Wayne Booth and E. D. Hirsch developed important New Criticism methods based on Aristotelian ways of thinking.