Professor Jeanne Fahnestock
http://www.otal.umd.edu/~mikej/supplements/ethoslogospathos.html

Ethos

According to Aristotle, our perception of a speaker or writer’s character influences how believable or convincing we find what that person has to say. This projected character is called the speaker or writer’s ethos. We are naturally more likely to be persuaded by a person who, we think, has personal warmth, consideration of others, a good mind and solid learning. Often we know something of the character of speakers and writers ahead of time. They come with a reputation or extrinsic ethos. People whose education, experience, and previous performances qualify them to speak on a certain issue earn the special extrinsic ethos of the authority. But whether or not we know anything about the speaker or writer ahead of time, the actual text we hear or read, the way it is written or spoken and what it says, always conveys and impression of the author’s character. This impression created by the text itself is the intrinsic ethos. 

Institutions, public roles and publications also project an ethos or credibility. We assume, for example, that The New York Times is a more credible source than the Weekly World News or the National Enquirer. And we usually assume that a person selected for a position of responsibility or honor is more credible than someone without official sanction. These expectations about credibility and ethos are occasionally disappointed. 



Pathos

The persuasive appeal of pathos is an appeal to an audience’s sense of identity, their self-interest, their emotions. Many rhetoricians over the centuries have considered pathos the strongest of the appeals, though this view of persuasion is rarely mentioned without a lament about the power of emotion to sway the mind.
                         
Appeals to our sense of identity and self interest exploit common biases; we naturally bend in the direction of what is advantageous to us, what serves our interests or the interests of any group we believe ourselves a part of. Even when advantage is not an issue, writers who belong to groups we identify with, or create groups we can belong to, often seem more compelling. We also naturally find more persuasive the speaker or writer who flatters us (especially indirectly) instead of insulting us. Thus skillful writers create a positive image in their words of the audience they are addressing, an image their actual readers can identify with. Who does not want to be the “sensible, caring person” the arguer describes? Especially powerful are devices that create an identity between the writer and reader so that the speaker almost seems to be the audience addressing itself. 
                         
The emotions also strongly assist, perhaps sometimes determine, persuasion. If, for example, a writer wants a reader to evaluate something negatively, she or he may try to arouse the reader’s anger. Or to produce action to someone’s benefit (e.g. to persuade us to make a charitable donation), an arguer may work on our pity. 
                         
Direct appeals to the reader to feel an emotion (e.g. “You should be crying now”) are rarely effective. Instead, creating an emotion with words usually requires recreating the scene or event that would in “real” circumstances arouse the emotion. Thus descriptions of painful or pleasant things work on the emotions. Or the arguer can work on the natural “trigger” of the emotion. If, for example, we usually feel anger at someone who, we believe, has received benefits without deserving them, then the arguer who wants to make us angry with someone will make a case that person was rewarded unfairly. 



Logos

Finally, we come to the “argument” itself, the explicit reasons [the logic] the arguer provides to support a position. There are many ways to describe the support provided in an argument, but a sample way to begin is to consider all the premises the author seems to supply. These can be scattered throughout the argument and expressed indirectly, so identifying premises is a judgment call in itself. 
                         
Next ask which of the premises are presented as objects of agreement that the arguer considers as given, elements of the argument taken for granted. Objects of agreement are basically either facts or values. Of course, the facts may not be facts and readers may not agree with the values assumed. Some of the premises will be supported further, but basically every argument has got to come down to certain objects of agreement that it presents as shared between arguer and audience. 
                         
You can also classify premises into the following categories. 
 

1. Are they arguments based on definition? In other words, does the arguer make claims about the nature of things, about what terms mean, what features things have? 
   
   
2. Does the arguer make analogies or comparisons? Does he or she cite parallel cases? 
   
   
3. Are there appeals to cause and consequences? Arguing from consequence is especially common when policy issues are debated. 
   
   
4. Does the arguer rely on testimony or authority by citing the received opinions of experts? Or does the author create some kind of authoritative reference group, citing public opinion on what most people think as support for his or her position?