I think O'Brien casts doubt on the truthfulness of the novel to continue supporting the point that everything ever said about a war is not entirely truthful. War has such a profound impact on people that they can't help but add a little bit of their own personal feelings and experiences into a story about the war. He wants the readers of the novel to understand that even what HE is saying is not entirely truthful. It's an interesting point that he makes, but part of me wishes that everything he says about the Vietnam War is true because the stories are so interesting. It decreases my understanding of the novel somewhat because now I don't know what to distinguish as real and fake. The difference between "story truth" and "happening truth" is that the happening truth is what actually happened. The story truth is for when people are telling others about what happened to them and the others that were with them, but addend new details to the story, ultimately making it more interesting. The story truth is