Here one of the first very important differences of interpretation comes in. Professor Butcher would translate ζῷον “picture,” as though it were short for ζῷον γεγραμμένον. Scholars differ whether the word _can_ by itself have this meaning, and on such a point I have no pretensions to decide. But its more common sense is certainly “living organism,” and I feel certain that this is the only meaning which makes full critical sense here. To begin with, Aristotle has just used it in this way, and in the second place the analogy of another _art_ would come in very ill. We want a comparison drawn from _nature_, to give us the law for the imitation of nature. We have, however, to go further. Not only must the action of tragedy be complete and probable, but it must deal with terrible and pitiful things: if these surprise us, so much the better. After distinguishing between simple plots (without Revolution and Discovery) or complex (with them), and describing these two elements at more length, he attacks, in a rather suspected passage, the Parts—Prologue, Episode, Exodus,[41] the choric part, &c.—and then, preferring the complex scheme, shows how it is to be managed. The hero must not blamelessly pass from prosperity to adversity, nor blamefully in the opposite direction. He must be a person of considerable position, who by some error or weakness (ἁμαρτία) comes to misfortune. Also the special kind of pity and terror which is to be employed to make him interesting, the _oikeia hedone_ of tragedy, is most important, not a few examples being taken in illustration from the great tragedians. Footnote 41: “Episode” is here defined in quite a new sense as the dialogue _between_ choruses; “Exodus” as that which no chorus follows. The chapter is doubtful—or something more. Then we pass to Character. It must be good—even a woman is good sometimes—it must be appropriate, true to life, and consistent. Probability is here as important as in Action; the _Deus ex machina_ is to be used with extreme caution. After turning to the details of Discovery, and dealing with Gesture, Scene, &c., he goes to the two main stages of Tragedy, _desis_ and _lusis_, Twisting and Unravelling, and to its four kinds (an extension of his former classification)—Simple, Complex, Pathetic, and Ethical. And the tragic poet is especially warned against Tragedy with an Epic structure—that is to say, a variety of plots. The Chorus must bear part in the action, and not give mere interludes.