One of the more iconic quotes from the novel relates to the idea of repeating the past. This is an interesting idea, open to various interpretations depending on how literally we want to understand it.
Recognizing the true nature and extremity of Gatsby's plan to marry Daisy and erase the intervening years between now and when they met, Nick protests to Gatsby that you cannot repeat the past.
Gatsby replies to the contrary:
“Can’t repeat the past?” he cried incredulously. “Why of course you can!”
Though, short of time travel, this sentiment is clearly literally impossible, there is a larger question to be asked of this idea. Is it possible to recapture a state of mind, an emotional state, or an idealized romance?
This is the true import of Gatsby's stance as he insists that with two consenting individuals the possibility of recapturing a moment (in spirit) is not only valid but, perhaps, inevitable. If two people want to be in love as they once were, to believe that life is beautiful and poetic, then what is to stop them?
This is the question that Gatsby's position poses to Nick's assertion that one cannot repeat the past. By no means should we presume that agreement with Gatsby's idea will be automatic. Nor should we presume agreement with Nick's position.
There is an argument to be made on both sides.