This unity, it is needless to say, plays an important part in Aristotle’s _Poetics_. He recognized that “plot is the first essential and soul of tragedy and that character comes second.”[332] The most lengthy statement runs as follows: “Let us now discuss the proper construction of the plot, as that is both the first and the most important thing in tragedy. We have laid it down that tragedy is an imitation of an action that is complete and whole, having a certain magnitude, for there is also a whole that is wanting in magnitude. Now a whole is that which has a beginning, a middle, and an end. A beginning is that which is not itself necessarily after anything else and after which something else naturally is or comes to be; an end, on the contrary, is that which itself naturally follows some other thing either as its necessary or usual consequent, and has nothing else after it; and a middle is that which is both itself after one thing and has some other thing after it. Accordingly, well-constructed plots must neither begin nor end at haphazard points, but must conform to the types just mentioned.”[333] These principles were excellently restated by Lowell: In a play we not only expect a succession of scenes, but that each scene should lead by a logic more or less stringent, if not to the next, at any rate to something that is to follow, and that all should contribute their fraction of impulse towards the inevitable catastrophe. That is to say, the structure should be organic, with a necessary and harmonious connection and relation of parts, and not merely mechanical with an arbitrary or haphazard joining of one part to another. It is in the former sense alone that any production can be called a work of art.[334] Though it is now admitted on all sides that the unity of action is the _sine qua non_ of dramatic composition, many fail to realize the meaning and extent of its limitation. Aristotle indicated a mistaken notion current in his day, and likewise in ours, in the following words: “The unity of a plot does not consist, as some suppose, in its having one man as its subject. An infinite multitude of things befall that one man, some of which it is impossible to reduce to unity, and so, too, there are many actions of one man which cannot be made to form one action. Hence, the error, as it appears, of all the poets who have composed a _Heracleid_, a _Theseid_, or similar poems. They suppose that, because Heracles was one man, the story also of Heracles must be one story.”[335] Freytag discussed the matter with keen discrimination and exemplified it by showing how Shakespeare remodeled the more or less chaotic story of Romeo and Juliet’s love into a unified plot whose incidents follow one another almost as inexorably as Fate. The passage is unfortunately too long for quotation here, but is highly instructive.[336]