The primary theme in Ernest Hemingway's short story "Soldier's Home" is Krebs' inability to relate to his mother and to home life after his return to Oklahoma following World War I. After witnessing death and destruction while participating in some of the war's most bloody battles, Krebs returns home where his parents try to coax him to return to his old routine. But his view of the world has been altered permanently, and attending ball games and dating are no longer easy for him. He no longer feels love in his heart and cannot bring himself to "lie" and tell his mother he still loves her. When he is asked to pray with his mother, he is also unable to do so. In one of Hemingway's most famous lines, "Krebs looked at the bacon fat hardening on his plate." Like the bacon, his heart has been hardened by what he has seen in Europe, and he knows he must get far away from his parents in order to get his life in order.
Certainly one of the topics that come to mind and stand out resonate in the story's title as they do in our own lives: adaptation. Here is a man who has gone through a life-changing event and has allegedly experienced a series of consequences caused by his own choices. As a result, he has to choose how to re-adapt himself to understanding a life, as he knew it, all over again.
With understanding life again comes a re-birth of mind and consciousness; of reality and truth. He has to re-visit all his value-system, his own mental substenance, traditions, and schema of life and transfer all that towards a new scheme that, in itself, is also new to him. It is hard to imagine being part of a world, then being taken to another, and then being returned to the original world from where you came and -suddenly- it is now completely incomprehensible to you. It is like two zones of reality continuously multiplying without control.
The need to understand, adapt, re-do, revisit, reinstate, and re-start are certainly what makes this story a journey to the main character.