Pathos is a rhetorical device used to persuade an audience by appealing to its emotions. As groups of people tend to be more emotionally suggestible than individuals, pathos is often used in speeches, both in the real world and in works of literature. A particularly good example of the latter comes in the shape of Mark Antony's speech in Act III Scene II of Julius Caesar. Mark Antony knows that his audience, the Roman plebs, loved Caesar, and so he blatantly plays on their emotions to show that he too felt the same way:
My heart is in the coffin there with Caesar,
And I must pause till it come back to me. (weeps)
Mark Antony knows his audience. And that's an important consideration for Aristotle
in his Rhetoric:
The Emotions are all those feelings that so change men as to affect their judgements, and that are also attended by pain or pleasure. Such are anger, pity, fear and the like, with their opposites. We must arrange what we have to say about each of them under three heads. Take, for instance, the emotion of anger: here we must discover (1) what the state of mind of angry people is, (2) who the people are with whom they usually get angry, and (3) on what grounds they get angry with them.
An expert rhetorician senses the mood of his audience and attempts to persuade them accordingly. Values and belief systems are important topics to use as they relate to the very core of the audience's being. Returning to Mark Antony's speech, we see that he skillfully plays upon the Roman mob's love of Caesar. In using pathos, he's telling his audience a story, one in which they themselves played a leading role. By flattering the mob's self image, Mark Antony is reducing the ability of his audience to judge rationally. In any case, why would they challenge his version of events when they already correspond with how they see things? Rational arguments can always be countered by other rational arguments. Emotional appeals, however, are much more difficult to counteract. And that's why Mark Antony's speech proves to be so incredibly successful.