Rhetorical appeals are argumentative strategies that are intended to convince a listener of particular points by arguing or appealing to certain aspects of the listener's character or personality. The three main rhetorical appeals are ethos, or an appeal based on the character of the speaker; logos, or an appeal based on logic and reason; and pathos, an appeal based on emotion. These appeals are all used in a variety of different settings, though some types are more common in some settings than in others. Emotional appeals, for instance, are particularly common in advertising while logic is more commonly used in academia and law.
Ethos, or an appeal based on the character of the speaker, requires the speaker to establish himself as an authority on the topic of discussion. He may do so by mentioning that he has years of relevant experience or has published important research in a given field. Rhetorical appeals based on reputation and character are often used to persuade large bodies of people who have little or no knowledge of a particular field to make certain decisions. Politicians, for instance, tend to appeal to voters by explaining how their past experiences and decisions make them good candidates. They hope to persuade potential voters to vote for them not based on the merits of their plans for the future but based on their character and expertise.
Appeals to reason, on the other hand, are based in careful and often formal logic aimed at demonstrating the validity of a certain claim. Rhetorical appeals based in logic are common in academic fields such as philosophy, in formal debates, and in law. Many conclusions in science are also presented through rhetorical appeals based on a logical progression from evidence to a general conclusion. In many settings, introducing rhetorical appeals based on emotion or authority into a logical argument is not considered to be appropriate, as logical appeals are generally evaluated strictly on the basis of the strength of the logical progression to a conclusion.
Emotional rhetorical appeals are usually intended to bring about a certain emotional response that ultimately prompts listeners into some course of action. Advertisements, for instance, often try to induce feelings of fear and insecurity that lead listeners to purchase certain products or services. Likewise, charities often use emotional appeals in the form of descriptions and images of suffering people in order to persuade people to donate time or money to their causes.