Persuasion in Written Language

What does it mean to write persuasively?

Most writers would simply state that persuasive writing convinces the reader. Period.

There are quite a few questions that follow that statement. For instance, does persuasive writing simply mean that the writer is communicating in a way that builds credibility and therefore is persuasive?

Some writing instructors would argue that all writing involves persuasion, that without persuading the reader of the believability of the text, the writer has failed.

Others would argue that persuasion means leading the reader to agree with the writer and possibly to take action according to what the writer is asking the reader to do. Think about advertising. A printed ad, a web ad, a radio ad — all of these use persuasive text. The reader or listener is being asked to take specific action, often action that may not have been taken without exposure to the ad. Truly persuading someone to do something requires carefully crafted language that cannot be refuted to the point of discouraging action.

So what, exactly, is persuasive language?