In The Great Gatsby, how does F. Scott Fitzgerald explore the human need to reconcile the uncertainties of the past with a new or present situation?
Perhaps the best way to answer this question is with an example. Jay Gatsby was never able to reconcile his past with the present, which is ultimately what leads to his demise. In his mind, Daisy is still the young debutant he shared a kiss with which made her blossom "for him like a flower and the incarnation was complete," instead of the mother and wife she is at the time of the novel.
Gastby's failure to recongnize time's effect on him is easily seen in two parts of the novel:
1. The first and most obvious way in which Gatsby is unable to reconcile the past with his present situation is his desire to make Daisy go to Tom and say, "I never loved you," before returning to Louisville and get married, like Gastby wanted to before the events in the novel occur. This desire is what prompts the most famous exchange of the novel, when Nick tells Gastby he can't repeat the past and Gatsby responds, "Can't repeat the past? [...] Why of course you can!"
2. Daisy's daughter also acts as a symbol for Gatsby's inability to reconcile the past with the present. While the reader sees Daisy's daughter only once in the novel, the little girl acts as an anchor for Daisy to remain with Tom and a visible (and living and breathing) reminder that she is not the same woman she was five years previous. While Daisy might not be a very good mother (she doesn't really interact with her daughter and she spends much of the novel away from her while carousing with Gatsby), she is nevertheless tied to her present. When Gatsby sees Daisy's daughter he is speechless. In fact, Nick says, "Gatsby kept looking at the child with surprise. I don't think he had ever really believed in its existence before."
Both of these details highlight Gatsby's difficulty in trying to find a place in the present because his entire character is moored on the idea of Daisy. He is incapable of reconciling the fact that Daisy has changed. This desire to make one's past make sense in the present is extremely human, which is what makes Gatsby such a relatable and tragic character.