§ II. On the purely literary line he tells us the parts:—[143]
(a) “The Prologos is that entire part of a tragedy which precedes the Parodos of the chorus” (see below for the Parodos). Thus a drama may have no “prologos” at all, for example the Persæ. The implications of our word “prologue” are derived from the practice of Euripides, who is fond of giving in his “prologos” an account of events which have led up to the action about to be displayed.
(b) “The Episode is that entire part of a tragedy which is between complete choric songs.” “Episodes” then are what we call “acts”: the name has already been explained.[144]
(c) “The Exodos is that entire part of a tragedy which has no choric song after it.” The few anapæsts which close most tragedies are not “choric songs”—they were performed in recitative. Thus the Exodos is simply the last act.
(d) “Of the choric part the Parodos is the first undivided utterance of the chorus: the Stasimon is a choric ode without anapæsts or trochees: the Commos is a joint lamentation of chorus and actors.” It will be seen later[145] that by excluding trochees he probably means the trochaic tetrameter as seen in dialogue; lyric trochees are very common.
§ III. On the strictly dramatic line he tells us the stages of structural development.
(a) “Every tragedy falls into two parts—Complication and Unravelling (or Dénouement).... By the Complication I mean all that comes between the beginning of the action and the part which marks the turning-point to good or bad fortune. The Unravelling is that which comes between the beginning of the change and the end.”[146]
(b) “Reversal (or Recoil, Peripeteia) is a change by which a train of action produces the opposite of the effect intended, subject always to our rule of probability or necessity. Thus in the Œdipus, the messenger comes to cheer Œdipus and free him from his alarms about his mother, but, by revealing who he is, he produces the opposite effect.”[147]
Much might be written on this analysis of dramatic structure. One remark at least must be made. It is not plain how much importance Aristotle allots to the Recoil or Peripeteia. We have seen that he did not regard it as indispensable. At the most he seems to think it a striking way of starting the dénouement. It is better to look upon it, and the action which leads up to it, as a separate part of the drama—and it may be argued that every tragedy, if not every comedy, has a Peripeteia—to form, in fact, that middle stage which elsewhere[148] in the Poetic he mentions as necessary.