We don't need to know his specific identity. If we did, Hemingway's story wouldn't be very effective, and it is very effective. Even though we don't know his specific identity, we do know enough about the narrator to make the story work. We know that he is young and essentially alone in a foreign country at war, wounded and feeling very isolated. Even though he is wounded, he doesn't feel brave when he compares himself to some of the other soldiers in rehabilitation. He is a sensitive young man. Through the narrator's experiences, especially in his relationship with the major, we develop insight into courage, endurance, loss, and human dignity. Hemingway did not need to tell us the narrator's name, home town, or family background in order to achieve his purposes in the story.