Sentence:  This margin between the real and invented is always arbitrary and blurry. But Welty suggests that it will always be here and that the task of literature is to remind us of it. We need the incredible just as we need the opportunities to differentiate between a story and an <WSD>unstory</WSD>. 
Meaning of the word marked with <WSD> tags:  a story which is unnoteworthy or unnewsworthy; nonstory