Define Hemingway’s famous “iceberg theory of composition”, the one that invites us to assume that 7/8 of what is really going on happens beneath the surface. In what sense is this a useful formulation for understanding Hemingway’s fiction or fiction in general?

Define Hemingway’s famous “iceberg theory of composition”, the one that invites us to assume that 7/8 of what is really going on happens beneath the surface. In what sense is this a useful formulation for understanding Hemingway’s fiction or fiction in general?