This is of course shown most truly in the character of Fowler in this wonderful book. From the very beginning of the story, Fowler, again and again, stresses his lack of involvement and his detached viewpoint. Consider the following quote:
I'm not involved. Not involved,' I repeated. It had become an article of my creed.
This is what defines Fowler as a character, and separates him from Pyle, who is summarised by his desire to become involved. Of course, what Fowler comes to realise is that it is impossible to remain completely detached, and that being human necessarily pulls us in to complex, messy relationships that force us to take sides and do not allow us to remain detached, however much we wish it.
This novel in many ways reminds me of another text, a short story by Camus called "The Guest." The protagonist in this short story reminds me a lot of Fowler, as he is a teacher who just wants to live his life in French-occupied North Africa and not to become embroiled in the political situation. However, when he is entrusted with a prisoner to take to the nearby town for execution, he finds that no matter how hard he tries, it is impossible to resist involvement.