divorce. Nick understands that Gatsby is being completely unreasonable and says that he "can't repeat the past."

Gatsby responds to Nick's rational comment by saying, "Can't repeat the past? ... Why of course you can! ... I'm going to fix everything just the way it was before ... She'll see." Gatsby has been enamored with Daisy for the past five years and has recreated his version of reality to include her as his wife. Gatsby is a dreamer who is completely disconnected from reality and refuses to accept that life has irrevocably changed since he dated Daisy.

Gatsby's faith in his dreams stems from his incredible ability to achieve nearly impossible feats. He has raised himself from the depths of poverty, ascended the social ladder, and formed a new identity. In Gatsby's mind, anything is possible. Unfortunately, he fails to recognize that one cannot change another person's heart or repeat the past.

Not only is Daisy married to a financially secure man, but she also has a daughter. Despite these facts, Gatsby feels that Daisy should uproot her life, leave Tom, and marry him. His unyielding belief in his dream highlights his naïve, delusional personality. Gatsby does not understand that there is no future beyond his affair and does not recognize that Daisy is a selfish woman who enjoys their dalliance but has no plans of leaving her secure lifestyle. Gatsby is married to his dream and never entertains the possibility that he cannot repeat the past.

In the late night hours following what will be Gatsby's final party, he is disappointed that Daisy was not impressed by the extravagant entertainment he provided. Nick tries to both comfort Gatsby and deliver a reality check by telling him that he shouldn't expect too much of Daisy and that he "can't repeat the past." Gatsby is incredulous when he replies "Can't repeat the past? Why of course you can!"

Gatsby is suffering from the delusion that he can somehow erase Daisy's marriage to Tom Buchanan, despite the fact that they have a daughter together. Gatsby's development is arrested; he fell in love with Daisy before he went to war, and he cannot accept the fact that she moved on with her life in his absence. He needed time to acquire the fortune that would make her accept him as her social equal, and the five years that have passed have proved fatal to his dream of marrying her. At this point in the novel, he has not realized that they have no future beyond their affair. In fact, to his dying day, he still holds out hope that he can make things like they were before he went to war.

Nick has the objectivity to see that Daisy is comfortable with the wealth, security, and social position that Tom Buchanan provides, even though he is unfaithful. He is trying to get Gatsby to understand her outlook, but Gatsby is still faithful to the dream that, to his way of thinking and valuing, is embodied by Daisy Fay.

In Chapter Six, Nick tells Gatsby that you can't repeat the past. This is Gatsby's reply:

“Can’t repeat the past?” he cried incredulously. “Why of course you can!”

To understand why Gatsby believes this, it is important to remember that repeating the past is Gatsby's reason for living. Remember that he has dedicated his life to winning back Daisy Buchanan, the girl he loved and wanted to marry before being sent off to fight in the war.

Since Daisy married Tom, Gatsby has devoted every ounce of his energy and all of his resources to become as rich as possible so that he can grab Daisy's attention and pick up where they left off all those years ago.

So, for Gatsby, his belief in repeating the past is unshakeable. It is his sole purpose for existing. Daisy is his world, and he will do anything it takes to get her back.

If it were not possible to repeat the past, then Gatsby would lose his reason for being. This explains why he cries "incredulously" (unwilling to believe what Nick says). He simply cannot accept that repeating the past is not possible. If this were true, all of his hopes and dreams would be shattered in an instant.

Gatsby replies that of course you can repeat the past. In fact, that belief has laid the foundation of his whole life for the past five years as he amassed the fortune that he believes now exceeds Tom Buchanan's. The money is necessary to attract Daisy, who Gatsby believes will now leave Tom for him.

Gatsby is confident that he repeat the past when he and Daisy first met. This time around, however, she will be his because he now has enough money.  His simplistic view reveals how completely he has skewed reality in his desperation to have the woman of his dreams.

Gatsby's response to Nick's observation that you can't repeat the past is incredulity.  He says, "Can't repeat the past? Why of course you can!"  To him, it seems perfectly reasonable to expect that Daisy would be able to tell Tom that she never loved him, and pick up where she left off with him, Gatsby, five years ago.  Gatsby is determined to "fix everything just the way it was before".  As he talks, Nick understands that in actuality, Gatsby wants to recover more than just Daisy.  He is looking for "something, some idea of himself perhaps, that had gone into loving Daisy".  His life has been incomplete since he lost her, and he somehow feels that if he could just go back and do it all again the right way, he would find the thing that he has been missing (Chapter VI).