In narrative theory, gapping refers to the fact that all texts necessarily omit some amount of information, leaving their readers to draw logical inferences and conclusions about that which is left out. Informational gaps in a narrative are necessary and ubiquitous. Narratives cannot possibly communicate every supposed thought and action of its characters nor every miniscule event of its fictional universe. A reader, then, is left to make some assumptions. For instance, if no information exists to suggest otherwise, one may infer that the characters of a novel eat and sleep on a regular basis even if the narrative does not detail these aspects of a character's daily life.
Authors make choices, of course, as to the narrative gaps they allow in their texts. When, for example, the eponymous narrator of Daniel Defoe's Robinson Crusoe shares with his audience that he kept a journal while shipwrecked on the island, Defoe seems unwilling to leave to the imagination of his readers the nature of that journal. Thus, Defoe's narrator, Crusoe, share its contents, despite the fact that it will, as Crusoe himself admits, lead to redundancies: "I began to keep my Journal, of which I shall here give you the Copy (tho' in it wll be told all these Particulars over again) as long as it lasted, for having no more Ink I was forc'd to leave it off" (104-105). A similar concern about narrative gaps seems present in Samuel Richardson's epistolary novel Pamela, in which Richardson takes pains to make explictely clear the means by which his heroine is able document her experiences, rather than ask his readers to make inferences about these logistical concerns. Pamela offers, for example, many such detailed descriptions as the following: "I had lost my Pen some how; and my Paper being wrote out, I stepp'd to Mr. Longman's our Steward's Office, to beg him to give me a Pen or two, and a Sheet or two of Paper," and "So I resolv'd to hide a Pen of my own here, and another there, for fear I should come to be deny'd" (50; 112).