In Chapter IV, Gatsby picks Nick up in his gaudy car to take him to lunch. Gatsby takes advantage of having Nick alone to tell him a story about himself which is obviously invented and rehearsed. He begins by saying:
"Well, I'm going to tell you something about my life. . . . I don't want you to get a wrong idea of me from all these stories you hear."
Nick is skeptical from the beginning. Gatsby is offering him an idealized account of himself, an autobiography he only wishes were true.
"I'll tell you the God's truth." His right hand suddenly ordered divine retribution to stand by. "I am the son of some wealthy people in the Middle West--all dead now. I was brought up in America but educated at Oxford, because all my ancestors have been educated there for many years. It is a family tradition."
Nick can tell from Gatsby's facial expressions and his tone of voice that he is lying. Gatsby seems especially embarrassed when he claims that he was educated at Oxford and that this was a family tradition. (It will come out later in the novel that Gatsby actually attended Oxford for a few months while he was serving as an army officer in Europe. This is where he picked up the expression "Old sport," which he uses far more often than a real Oxford man would have used it.)
Gatsby makes a faux pas in telling Nick he is from the Middle West, because Nick is from the Middle West himself and knows the region thoroughly. Nick would certainly know of a wealthy family named Gatsby. The statement made by Gatsby that gives Nick positive proof he is lying about his past is contained in the following very simple question and answer.
"What part of the Middle West?" I inquired casually.
San Francisco, of course, is in the Far West. It is as far west as anyone can go without crossing the Pacific Ocean.
Nick can be an amusing character. When he says, "I see," he seems to be saying one thing to Gatsby and something else to himself. To Gatsby he is simply confirming that he understands and accepts where Gatsby comes from, but to himself he is saying that he sees Gatsby is ignorant about the geography of America and that his whole story is a romantic fiction.
Gatsby would have been better off remaining an aloof and mysterious figure. When he tries to come out of his shell he merely reveals himself as an imposter and a member of the nouveau riche. He is rather a pathetic character because he doesn't want to live a lie; he is only trying to create an impressive role for the sake of winning Daisy. When Tom Buchanan exposes him as a bootlegger and racketeer, he is unable to defend himself because his elaborate facade is too flimsy and vulnerable.
Nick likes the real Gatsby much better than the fake Gatsby, and Daisy probably does too. The real Gatsby is innocent and sincere, especially in his love for Daisy. He was a handsome army officer and served heroically in World War I. He wanted badly to improve himself and jumped at the chance to attend Oxford, if only for a few months. The fact that he is obviously so embarrassed about telling Nick all his lies is to his credit, as is the fact that his facade is so easily demolished by Tom Buchanan later in the novel.
Nick himself demonstrates how easy it would be to demolish Gatsby's colorful autobiography when he asks, "What part of the Middle West?" and Gatsby automatically gives the revealing rehearsed reply: