The closest English equivalent to the Greek word ethos is probably "image"--the way the writer "appears" to the reader within the text itself. Though history is full of people who have attempted to hide evil purposes under a good ethos, we by no means suggest that ethos is concerned merely with a good appearance. The best way for a writer to show that she is possessed of a good ethos is for her to actually have a good ethos. We must keep in mind the idea that the English word "ethics" is derived from the Greek ethos.
In his Rhetoric, Aristotle states that there are three subsets to ethos: good will, good character, and good sense. If a writer shows that he has good will for his audience, he will indicate indirectly, by the tone and content of his words, that what he proposes in his argument is beneficial not just to himself and people like him but to others as well. A writer who has good character is possessed of what we might call the commonly-acknowledged virtues (fairness, unselfishness, integrity, honesty, etc.) but is not moralistic or preachy. The writer who has good sense is, if not an expert on the matters she discusses, well informed on her subject matter, capable of making good judgments on the information at hand, and ever watchful for specious arguments. In academic and workplace settings, one's ability to use standard English well is important in creating an image of good sense. In short, the writer who has a good ethos is aware of himself and the image he gives off, is self critical when she needs to be, and is always aware and (except for extreme cases) is respectful of opposing viewpoints. Like all other writers, Composition students cannot choose to have ethos-less papers. Since an ethos of some sort is always present in written (and spoken) work, writers are well advised to show they have good sense, good will, and good character.
To demonstrate how ethos is a key part of persuasion, let's look at an excerpt from a written speech delivered several decades ago. In 1952, Eisenhower chose a young senator from California named Richard Nixon as his vice presidential running mate. By late summer, as a number of newspapers began charging that Nixon had been the recipient of an illegal slush fund, Eisenhower considered dropping Nixon from the ticket. Nixon persuaded Eisenhower to let him appear on TV, which in 1952 was fairly new, to explain his financial dealings over his lifetime and in the process exonerate himself. The speech Nixon gave on 23 September 1952 has come to be known as the "Checkers Speech," for a reason the reader will see:
I was born in 1913. Our family was one of modest circumstances and most of my early life was spent in a store out in East Whittier. It was a grocery store -- one of those family enterprises. The only reason we were able to make it go was because my mother and dad had five boys and we all worked in the store. I worked my way through college and to a great extent through law school. And then, in 1940, probably the best thing that ever happened to me happened, I married Pat -- who is sitting over here. We had a rather difficult time after we were married, like so many of the young couples who may be listening to us. I practiced law; she continued to teach school. Then in 1942 I went into the service. Let me say that my service record was not a particularly unusual one. I went to the South Pacific. I guess I'm entitled to a couple of battle stars. I got a couple of letters of commendation but I was just there when the bombs were falling and then I returned. I returned to the United States and in 1946 I ran for the Congress.
[For the next few moments, Nixon gives a detailed account of his financial dealings over the past several years]
Well, that's about it. That's what we have and that's what we owe. It isn't very much but Pat and I have the satisfaction that every dime that we've got is honestly ours. I should say this -- that Pat doesn't have a mink coat. But she does have a respectable Republican cloth coat. And I always tell her that she'd look good in anything.
One other thing I probably should tell you because if we don't they'll probably be saying this about me too, we did get something--a gift--after the election. A man down in Texas heard Pat on the radio mention the fact that our two youngsters would like to have a dog. And, believe it or not, the day before we left on this campaign trip we got a message from Union Station in Baltimore saying they had a package for us. We went down to get it. You know what it was. It was a little cocker spaniel dog in a crate that he'd sent all the way from Texas. Black and white spotted. And our little girl -- Tricia, the 6-year old -- named it Checkers. And you know, the kids, like all kids, love the dog and I just want to say this right now, that regardless of what they say about it, we're gonna keep it.
The speech, one of the most famous given by an American politician in the twentieth century, was a resounding success. Though Nixon's own presidency would be in serious trouble with the Watergate scandal by the early 1970s, he went on to serve two terms as vice president under Eisenhower. There is much to say about this small excerpt. The most striking instance of pathos (emotional appeal) occurs with the last paragraph, as Nixon indignantly (and somewhat speciously) declares that his family is "gonna keep" their puppy Checkers; his accusers, the "they" of the last sentence, are certainly very bad people if they don't care about puppies and six-year-olds. And Nixon's apparently forthright and complete itemization of his finances is meant to be a logical dismissal of his critics' charges.
The ethos of the excerpt is strongest in the first paragraph. Over and over, Nixon seeks to identify himself with his imagined audience. He establishes himself as a family person, as a hard worker, a committed husband, as someone who (" like so many of the young couples who may be listening to us") had a hard time financially, and as a patriot ("entitled to a few battle stars") who fought in World War II. Since the whole point of the speech is to show the American people (and Eisenhower) that he is honest and trustworthy, incapable of receiving illegal funds, his chief goal is to show that he has good character. The first excerpted paragraph is a list of mainstream, middle-class values, especially as they were in the 1950s in the U.S. Perhaps Nixon's speech would not work so well today, an age that--in part because of trust-busting scandals such as Watergate--is more skeptical than it was a half century ago.
Student writers should always be aware of ethos. The writer who fails to account for his own image and who may intend to project confidence, a high sense of ethics, and intelligence runs the risk of coming across as a cocky, overly moralistic know-it-all. As far as ethos goes, the best advice for writers is that they be themselves and work toward realizing their "voices" through practice, reading, careful drafting, and feedback from others.