Using action and limited knowledge to portray emotion
In Big Hearted River, we are introduced to a new side of the post-war Nick. Now that he is free from society and on his own in the wild, Nick is presented as relaxed, comfortable, and at home. This is a sharp contrast from the traumatized and apathetic Nick we saw in Soldier's Home. To convey the message of a troubled veteran finding inner peace in the serenity of nature, Hemingway uses detailed description of the the actual events in the story while providing us only a limited understanding of Nick's desires, experiences and motives.
Throughout the story, Hemingway meticulously details nearly all of Nick's actions. From this alone we can infer a great deal about how he has been changed by the war and in conjunction with the other stories why this change took place. The tranquility of nature reminds Nick of when he was a child and when life was simpler. By using powerful imagery, Hemingway creates a portrait of Nick's quest to escape his painful war memories.
Although it is easy to see how and even partly why detachment from civilization is calming for Nick, there is a great deal about Nick that is not revealed. Things like why Nick often seems to blissfully regress into ignorance, why he seems content in making arbitrary choices (camp location), and why he avoids getting too excited are simply stated and no indication as to what Nick's reasoning is can be found. By forcing the reader to read between the lines and interpret Nick's actions, Hemingway brings the character to life.
Detailed imagery of Nick's actions and environment show the reader what Nick sees and why he feels at peace in nature. Leaving some of his motives and psychology unknown creates a more complex character and also shows how only someone who has experienced certain tragic events can ever comprehend their significance.