A General Summary of Aristotle's Appeals . . .
The goal of argumentative writing is to persuade your audience that your ideas are valid, or more valid than someone else's. The Greek philosopher Aristotle divided the means of persuasion, appeals, into three categories--Ethos, Pathos, Logos.
Ethos (Credibility), or ethical appeal, means convincing by the character of the author. We tend to believe people whom we respect. One of the central problems of argumentation is to project an impression to the reader that you are someone worth listening to, in other words making yourself as author into an authority on the subject of the paper, as well as someone who is likable and worthy of respect.
Pathos (Emotional) means persuading by appealing to the reader's emotions. We can look at texts ranging from classic essays to contemporary advertisements to see how pathos, emotional appeals, are used to persuade. Language choice affects the audience's emotional response, and emotional appeal can effectively be used to enhance an argument.
Logos (Logical) means persuading by the use of reasoning. This will be the most important technique we will study, and Aristotle's favorite. We'll look at deductive and inductive reasoning, and discuss what makes an effective, persuasive reason to back up your claims. Giving reasons is the heart of argumentation, and cannot be emphasized enough. We'll study the types of support you can use to substantiate your thesis, and look at some of the common logical fallacies, in order to avoid them in your writing.
Ethos, Pathos, and Logos.
Logos (Greek for 'word') refers to the internal consistency of the message--the clarity of the claim, the logic of its reasons, and the effectiveness of its supporting evidence. The impact of logos on an audience is sometimes called the argument's logical appeal.
Ethos (Greek for 'character') refers to the trustworthiness or credibility of the writer or speaker. Ethos is often conveyed through tone and style of the message and through the way the writer or speaker refers to differing views. It can also be affected by the writer's reputation as it exists independently from the message--his or her expertise in the field, his or her previous record or integrity, and so forth. The impact of ethos is often called the argument's 'ethical appeal' or the 'appeal from credibility.'
[P]athos (Greek for 'suffering' or 'experience') is often associated with emotional appeal. But a better equivalent might be 'appeal to the audience's sympathies and imagination.' An appeal to pathos causes an audience not just to respond emotionally but to identify with the writer's point of view--to feel what the writer feels. In this sense, pathos evokes a meaning implicit in the verb 'to suffer'--to feel pain imaginatively.... Perhaps the most common way of conveying a pathetic appeal is through narrative or story, which can turn the abstractions of logic into something palpable and present. The values, beliefs, and understandings of the writer are implicit in the story and conveyed imaginatively to the reader. Pathos thus refers to both the emotional and the imaginative impact of the message on an audience, the power with which the writer's message moves the audience to decision or action.
[The above text drawn verbatim from Ramage, John D. and John C. Bean. Writing Arguments. 4th Edition. Needham Heights, MA: Allyn & Bacon, 1998, 81-82.]