Aristotle details what individual emotions are useful to a speaker (Book 2.2.27). In doing so, Aristotle focused on whom, toward whom, and why, stating that "t is not enough to know one or even two of these points; unless we know all three, we shall be unable to arouse anger in anyone. The same is true of the other emotions." He also arranges the emotions with one another so that they may counteract one another. For example, one would pair sadness with happiness (Book 2.1.9).