Rhetorical approaches can be described in terms of the means of persuasion used or in terms of the purpose of a particular rhetorical work. The three primary means of persuasion, as outlined by Aristotle in his treatise Ars Rhetorica, are ethos, pathos, and logos. Likewise, there are three primary purposes for classic rhetorical works, also described by Aristotle as rhetorical species. These approaches include legislative, forensic, and ceremonial, otherwise known as deliberative, judicial, and epideitic.
As rhetorical approaches, logos, ethos, and pathos dictate how a speaker or writer appeals to an audience in an effort to persuade or otherwise influence in the audience. Logos uses facts and logic to persuade, focusing on arguments of induction or deduction. Induction begins with a specific instance and leads the audience to general understandings, whereas deduction takes the audience from a general understanding to a specific instance. Pathos uses emotion to appeal to an audience, relying on responses such as anger, fear, love, or pity.
Ethos, the final of the three rhetorical approaches based on persuasive method, involves constructing credibility in the eyes of the audience. A speaker or writer must establish his or her own ethical or moral credibility in an effort to bring the audience into agreement with a particular point of view. He or she accomplishes this through goodwill, common sense, intelligent presentation, and establishing himself or herself as a virtuous individual of good character.
In terms of approaches based on purpose, classic rhetoric was historically divided into three branches based on factors such as the audience and the topic being discussed. Each purpose, whether legislative, judicial, or ceremonial, required different approaches and means of persuasion. Students of rhetoric were taught how to identify which approach was most appropriate based on the topic and audience.
Legislative rhetoric was, and still is, politically oriented. Known formally as deliberative rhetoric, its purpose is to dissuade a political point of view, exhort another view, or both. Judicial rhetorical approaches, also known as forensic rhetoric, are intended to accuse or defend based on the point of view taken. For example, dramatic, flowery closing arguments made at a criminal trial would be considered judicial rhetoric, since these arguments are meant to persuade a jury to convict or exonerate a defendant.
Finally, epideitic or ceremonial rhetoric, also known as demonstrative rhetoric, is intended to offer either blame or praise. Such rhetorical approaches are typically used for any persuasive work that does not fall under political or judicial topics. While legislative, forensic, and ceremonial are not the only purposes for rhetoric, they are the most common instances where rhetoric is used.