"The intellectual context that you establish for your topic and thesis at the start of your essay, in order to suggest why someone, besides your instructor, might want to read an essay on this topic or need to hear your particular thesis argued—why your thesis isn’t just obvious to all, why other people might hold other theses (that you think are wrong). Your motive should be aimed at your audience: it won’t necessarily be the reason you first got interested in the topic (which could be private and idiosyncratic) or the personal motivation behind your engagement with the topic. Indeed it’s where you suggest that your argument isn’t idiosyncratic, but rather is generally interesting. The motive you set up should be genuine: a misapprehension or puzzle that an intelligent reader (not a straw dummy) would really have, a point that such a reader would really overlook. Defining motive should be the main business of your introductory paragraphs, where it is usually introduced by a form of the complicating word 'But.'" -- Gordon Harvey, "The Elements of the Academic Essay"

see also audience