is by nature after one thing and has also another after it. A
well-constructed Plot, therefore, cannot either begin or end at any
point one likes; beginning and end in it must be of the forms just
described. Again: to be beautiful, a living creature, and every whole
made up of parts, must not only present a certain order in its
arrangement of parts, but also be of a certain definite magnitude.
Beauty is a matter of size and order, and therefore impossible either
(1) in a very minute creature, since our perception becomes indistinct
as it approaches instantaneity; or (2) in a creature of vast
size--one, say, 1,000 miles long--as in that case, instead of the
object being seen all at once, the unity and wholeness of it is lost
to the beholder.

Just in the same way, then, as a beautiful whole made up of parts, or
a beautiful living creature, must be of some size, a size to be taken
in by the eye, so a story or Plot must be of some length, but of a
length to be taken in by the memory. As for the limit of its length,
so far as that is relative to public performances and spectators, it
does not fall within the theory of poetry. If they had to perform a
hundred tragedies, they would be timed by water-clocks, as they are
said to have been at one period. The limit, however, set by the actual
nature of the thing is this: the longer the story, consistently with
its being comprehensible as a whole, the finer it is by reason of its
magnitude. As a rough general formula, 'a length which allows of the
hero passing by a series of probable or necessary stages from
misfortune to happiness, or from happiness to misfortune', may suffice
as a limit for the magnitude of the story.