Iceberg theory

Hemingway's iceberg theory, from Death in the Afternoon (1932): a writer who knows enough "may omit things that he knows and the reader... will have a feeling of those things as strongly as though the writer had stated them. The dignity of movement of an ice-berg is due to only one-eighth of it being above water."

His own caveat is usually dropped in retellings and is the part worth keeping: "A writer who omits things because he does not know them only makes hollow places in his writing." Omission is a technique for writers who know what they are omitting. The theory underlies minimalist prose, and it is the structural cousin of show, don't tell.