(_ββ_) The term Unity, if employed in this general sense, has become a very commonplace one even for tragedy, one capable of much misuse. For every event, in its causes and effects, creates an infinite chain, which, in the direction of the past no less than the future, and in a way that is in both directions incalculable, leads to a further series of particular circumstances and actions, it being impossible to determine all that may form part of the circumstances and detail in other respects, or the mode of their coalescence. If we merely confine our attention to this series, no doubt an Epos may be extended backwards and forwards indefinitely; and, over and above this such always offers opportunity for digression. But it is just such a series as this which makes the composition prosaic. To adduce an example the Greek cyclic poets have celebrated the entire cyclus of the Trojan war, and in doing so continue at the point where Homer stops, with a beginning, too, from the egg of Leda. But it is precisely on account of this that they degenerate into prose, if we contrast them with Homer's compositions. Just as little--I have already drawn attention to this--can an individual as such surrender the central focus of his unity, inasmuch as it is from this that the most varied events issue, and are able to effect a union in the same, though they may be entirely without connection regarded simply as events. We have consequently to seek for another type of unity. In this respect we must briefly determine the distinction between a mere _event_, and a _definite action_, which accepts the form of event in the epic narrative. We may define a mere event as the external aspect and realization of every human action, without involving with it the execution of a particular end; or, in general terms, we may call it every external modification in the form and appearance of what actually exists. When anyone is struck by lightning, that is a mere event, an external occurrence. More is implied in the sack of a hostile city; we have here the fulfilment of a predeterminate purpose. An essentially distinct object of this kind, such as the liberation of the Holy Land from the yoke of the Saracens and heathen, or better still the satisfaction of a specific impulse, such as the wrath of Achilles, must, under the mode of the epic eventuality, constitute the synthetic unity of the Epopaea; and by this I mean that the poetic narrative must restrict itself to that which is uniquely the effect of this conceived purpose or specific impulse, and in this co-operation be rounded off in an essentially exclusive unity. Action and execution of this type is, however, only possible to human agency; so that, as the culminating point of our composition, we must have in progressive conjunction with purpose and impulse a _human personality._ Furthermore, if the action and satisfaction of the entire heroic character, from which both