I think that at the half way point of the work, Changez is enduring a sort of existential crisis. There is much in flux around him and within him. In terms of external realities, Changez has come to the realization that his two loves are not authentic. Both America and Erica are not sincere in their love of him. Changez perceives Erica to be immersed in a nostalgia for her past love with Chris. She is incapable of viewing reality in any other way except for the love she had with Chris. This nostalgia of the past makes any interactions in the present and future worthless unless they can be seen in that framer. Interestingly enough, Changez senses the same mode of perception in America. The attacks of September 11 are something that Changez notes do not initiate a sense of reflection or rumination. Rather, they trigger a nostalgia to a World War II sense of self in which America is able to march triumphantly through the world with little if any consideration about its place in it and its impact on others. In this nostalgia, Changez realizes or perceives that he no longer has a place in this vision. Internally, all of this begins to trigger the gnawing feeling inside Changez that he does not fit into where he is in America. There is something uneasy within him that he cannot identify that makes him fundamentally uncomfortable with being in America. The combination of this external and internal discomfort with reality helps to heavily influence and even dictate his sense of existence half way through the novel.