Aristotle and the 3 Methods of Persuasion
It could be argued that the goal of any kind of writing is to effect change upon the reader.
The goal of simple, argumentative writing is to persuade the reader that the writer’s ideas are valid, or more valid than someone else's. Aristotle divided persuasion into three categories - Ethos, Pathos, Logos.
Ethos could be called ‘credibility’ or ‘ethical appeal’. Here, the character of the author itself is a persuasive factor: people tend to believe and follow those whom they respect. To be successful at this, the writer has to project the impression to the reader that he or she is someone worth listening to, an authority on the subject of the writing, but also someone who is likeable and worthy of respect.
According to Aristotle, readers are naturally more likely to be persuaded by a person who, we think has personal warmth, is considerate of others, possesses a good mind and solid learning. In modern publishing, though, readers don’t meet writers and hardly ever know anything about them, so ethos has to be signalled in other ways. Sometimes we know something of the character of speakers and writers ahead of time, but normally in texts we hear or read, the way it is written or spoken, its content, convey impressions of the author's character.