This "sluggish avoidance of needless invention," which is
characteristic of Shakspere--and of Molière also, altho in a less
degree--is evidenced not only by their eager adoption of an accepted
type of play, an outer form of approved popularity, it is obvious also
in their plots, wherein we find situations, episodes, incidents drawn
from all sorts of sources. In all the twoscore of Shakspere's plays,
comic and tragic and historic, there are very few, indeed, the stories
of which are wholly of his own making. The invention of Molière is not
quite so sluggish; and there are probably three or four of his plays the
plots of which seem to be more or less his own; but even in building up
these scant exceptions he never hesitated to levy on the material
available in the two hundred volumes of uncatalogued French and Spanish
and Italian plays, set down in the inventory of his goods drawn up at
his death. Apparently Shakspere and Molière accepted in advance Goethe's
theory that much time may be lost in mere invention, whereas, "with a
given material all goes easier and better. Facts and characters being
provided, the poet has only the task of animating the whole. He
preserves his own fulness ... since he has only the trouble of
execution."

It has long been a commonplace of criticism that great poets seldom
invent their myths; and it may in time become a commonplace of
criticism that they seldom invent their forms. But in default of the
lesser invention, they have the larger imagination; and there is no
pedantry in seeking to emphasize the distinction between these two
qualities, often carelessly confused. Invention is external and
imagination is internal. The poets, by the mere fact that they are
poets, possess the power of imagination, which alone gives vitality and
significance to the ready-made plots they are willing to run into