Simple and Complex Plots
Aristotle, always concerned to establish categories to assist him in his analysis, offers in this brief chapter a distinction between the simple plot and the complex plot. These definitions will become more clear as Aristotle develops them in following chapters.

The simple plot represents a change of fortune which does not come about through a reversal of the situation and does not involve recognition on the part of the hero.

In the complex plot, the change of fortune emerges of necessity from the events preceding it. It is brought about through a reversal of the situation or recognition, or both.

In Aspects of the Novel, E. M. Forster makes a distinction between "story" and "plot" that corresponds quite closely to Aristotle's distinction between simple and complex plots. "'The king died and then the queen died' is a story," Forster writes. "The king died, and then the queen died of grief' is a plot" (86).

The significant difference, Aristotle concludes, lies in whether the final outcome of the plot is simply post hoc ("after") or, as in the case of complex plots, propter hoc ("because of").