The German critic Wolfgang Iser has described how gaps work in The Act of Reading: A Theory of Aesthetic Response (1976). Iser argues that texts contain gaps or blanks that powerfully affect the reader, who must explain them, connect what they separate, and create in his or her mind aspects of a work that aren’t in the text but are motivated by the text.
A more homey way to put it is to say that Nelson is offering the reader a very effective version of the ring-toss experiment that I talk about in Chapter 2. People seldom say everything they think or mean when they are interacting with others. Here we are given the basics—really, the least important elements of the interaction. The crucial elements are the ones we come up with ourselves.