this is a distinct thing from goodness and propriety, as here described. The fourth point is consistency: for though the subject of the imitation, who suggested the type, be inconsistent, still he must be consistently inconsistent. As an example of motiveless degradation of character, we have Menelaus in the Orestes; of character indecorous and inappropriate, the lament of Odysseus in the Scylla, and the speech of Melanippe; of inconsistency, the Iphigenia at Aulis—for Iphigenia the suppliant in no way resembles her later self.
As in the structure of the plot, so too in the portraiture of character, the poet should always aim either at the necessary or the probable. Thus a person of a given character should speak or act in a given way, by the rule either of necessity or of probability; just as this event should follow that by necessary or probable sequence. It is therefore evident that the unraveling of the plot, no less than the complication, must arise out of the plot itself, it must not be brought about by the Deus ex Machina—as in the Medea, or in the return of the Greeks in the Iliad. The Deus ex Machina should be employed only for events external to the drama—for antecedent or subsequent events, which lie beyond the range of human knowledge, and which require to be
