The aim of tragedy, Aristotle writes, is to bring about a “catharsis” of the spectators — to arouse in them sensations of pity and fear, and to purge them of these emotions so that they leave the theater feeling cleansed and uplifted, with a heightened understanding of the ways of gods and men. This catharsis is brought about by witnessing some disastrous and moving change in the fortunes of the drama’s protagonist (Aristotle recognized that the change might not be disastrous, but felt this was the kind shown in the best tragedies — Oedipus at Colonus, for example, was considered a tragedy by the Greeks but does not have an unhappy ending).

According to Aristotle, tragedy has six main elements: plot, character, diction, thought, spectacle (scenic effect), and song (music), of which the first two are primary. Most of the Poetics is devoted to analysis of the scope and proper use of these elements, with illustrative examples selected from many tragic dramas, especially those of Sophocles, although Aeschylus, Euripides, and some playwrights whose works no longer survive are also cited.

Several of Aristotle’s main points are of great value for an understanding of Greek tragic drama. Particularly significant is his statement that the plot is the most important element of tragedy:

Tragedy is an imitation, not of men, but of action and life, of happiness and misery. And life consists of action, and its end is a mode of activity, not a quality. Now character determines men’s qualities, but it is their action that makes them happy or wretched. The purpose of action in the tragedy, therefore, is not the representation of character: character comes in as contributing to the action. Hence the incidents and the plot are the end of the tragedy; and the end is the chief thing of all. Without action there cannot be a tragedy; there may be one without character. . . . The plot, then, is the first principle, and, as it were, the soul of a tragedy: character holds the second place.

Aristotle goes on to discuss the structure of the ideal tragic plot and spends several chapters on its requirements. He says that the plot must be a complete whole — with a definite beginning, middle, and end — and its length should be such that the spectators can comprehend without difficulty both its separate parts and its overall unity. Moreover, the plot requires a single central theme in which all the elements are logically related to demonstrate the change in the protagonist’s fortunes, with emphasis on the dramatic causation and probability of the events.

Aristotle has relatively less to say about the tragic hero because the incidents of tragedy are often beyond the hero’s control or not closely related to his personality. The plot is intended to illustrate matters of cosmic rather than individual significance, and the protagonist is viewed primarily as the character who experiences the changes that take place. This stress placed by the Greek tragedians on the development of plot and action at the expense of character, and their general lack of interest in exploring psychological motivation, is one of the major differences between ancient and modern drama.

Since the aim of a tragedy is to arouse pity and fear through an alteration in the status of the central character, he must be a figure with whom the audience can identify and whose fate can trigger these emotions. Aristotle says that “pity is aroused by unmerited misfortune, fear by the misfortune of a man like ourselves.” He surveys various possible types of characters on the basis of these premises, then defines the ideal protagonist as

. . . a man who is highly renowned and prosperous, but one who is not pre-eminently virtuous and just, whose misfortune, however, is brought upon him not by vice or depravity but by some error of judgment or frailty; a personage like Oedipus.

In addition, the hero should not offend the moral sensibilities of the spectators, and as a character he must be true to type, true to life, and consistent.

The hero’s error or frailty (harmartia) is often misleadingly explained as his “tragic flaw,” in the sense of that personal quality which inevitably causes his downfall or subjects him to retribution. However, overemphasis on a search for the decisive flaw in the protagonist as the key factor for understanding the tragedy can lead to superficial or false interpretations. It gives more attention to personality than the dramatists intended and ignores the broader philosophical implications of the typical plot’s denouement. It is true that the hero frequently takes a step that initiates the events of the tragedy and, owing to his own ignorance or poor judgment, acts in such a way as to bring about his own downfall. In a more sophisticated philosophical sense though, the hero’s fate, despite its immediate cause in his finite act, comes about because of the nature of the cosmic moral order and the role played by chance or destiny in human affairs. Unless the conclusions of most tragedies are interpreted on this level, the reader is forced to credit the Greeks with the most primitive of moral systems.

It is worth noting that some scholars believe the “flaw” was intended by Aristotle as a necessary corollary of his requirement that the hero should not be a completely admirable man. Harmartia would thus be the factor that delimits the protagonist’s imperfection and keeps him on a human plane, making it possible for the audience to sympathize with him. This view tends to give the “flaw” an ethical definition but relates it only to the spectators’ reactions to the hero and does not increase its importance for interpreting the tragedies.

The remainder of the Poetics is given over to examination of the other elements of tragedy and to discussion of various techniques, devices, and stylistic principles. Aristotle mentions two features of the plot, both of which are related to the concept of harmartia, as crucial components of any well-made tragedy. These are “reversal” (peripeteia), where the opposite of what was planned or hoped for by the protagonist takes place, as when Oedipus’ investigation of the murder of Laius leads to a catastrophic and unexpected conclusion; and “recognition” (anagnorisis), the point when the protagonist recognizes the truth of a situation, discovers another character’s identity, or comes to a realization about himself. This sudden acquisition of knowledge or insight by the hero arouses the desired intense emotional reaction in the spectators, as when Oedipus finds out his true parentage and realizes what crimes he has been responsible for.

Aristotle wrote the Poetics nearly a century after the greatest Greek tragedians had already died, in a period when there had been radical transformations in nearly all aspects of Athenian society and culture. The tragic drama of his day was not the same as that of the fifth century, and to a certain extent his work must be construed as a historical study of a genre that no longer existed rather than as a description of a living art form.

In the Poetics, Aristotle used the same analytical methods that he had successfully applied in studies of politics, ethics, and the natural sciences in order to determine tragedy’s fundamental principles of composition and content. This approach is not completely suited to a literary study and is sometimes too artificial or formula-prone in its conclusions.

Nonetheless, the Poetics is the only critical study of Greek drama to have been made by a near-contemporary. It contains much valuable information about the origins, methods, and purposes of tragedy, and to a degree shows us how the Greeks themselves reacted to their theater. In addition, Aristotle’s work had an overwhelming influence on the development of drama long after it was compiled. The ideas and principles of the Poetics are reflected in the drama of the Roman Empire and dominated the composition of tragedy in western Europe during the seventeenth, eighteenth, and nineteenth centuries.