The significance of the past is critical to understanding the novel and the character of Gatsby. The love/hate relationship that Gatsby has with the past, adds to the complexity of his characterization and brings to light the duality found within the human psyche. The allure of past stemmed from something that Gatsby longed for: the comfort of a simpler, better, nobler time; a time when values such as loyalty, honor, and virtue were sacrosanct. On the other hand, the past was something that Gatsby tried to create distance from by transforming himself from James Gatz, a poor mid-western boy, to Jay Gatsby, the “great” rich entrepreneur. Nick understands that Gatsby’s obsession with Daisy stems, in part, from Gatsby’s need to recapture some of his past. Gatsby needs not to just recapture his past with Daisy but possibly, his past true self.
Gatsby sees Daisy as embodying the past that can be again in the future. Nick tells Gatsby that the past cannot be repeated. To which Gatsby responds in incredulous disbelief: “Can’t repeat the past?” …... “Why of course you can!” Gatsby is obsessed with returning to that distant time, five years past, when he and Daisy first met and fell in love and she promised to wait for Gatsby to return from the war, when they would be reunited and live happily ever after. It was a time of innocence, idealism, and romance; which embodied Gatsby’s larger dream.
Gatsby's view of the past is an unusual one because he felt that the past could be repeated. In chapter 6, when Nick and Gatsby are talking after the party that Daisy and Tom attended, Nick warns Gatsby that he shouldn't ask too much of Daisy. Nick is thinking of the fact that Daisy has obligations: she's a wife and a mother. He sees that Gatsby wants to be able to ignore the five years that have passed since Gatsby first fell in love with Daisy. Gatsby wants the impossible - he wants the Daisy of five years ago. He believes that if Daisy were to leave Tom and go away with him that the two of them could pick up exactly where they left off before Gatsby went to war and totally ignore the years that have passed and the lives that were lived in those years. He is so caught up in his desire for Daisy that he doesn't think clearly.
Gatsby says to Nick, "Can't repeat the past? Why, of course you can!".
That in essence sums up Gatsby's view of the past. He is disillusioned by all the glories of his past; especially by his romance with Daisy. He sets out to achieve all the wonders of the past without realized that the moment (excuse the pun) has passed. His obsession with the past becomes his fatal flaw.
In all honesty, if you are actively reading the Great Gatsby, and allowing yourself to become captivated by it, you should have no matters in question as regards to the recovery of the past. It is one of the most vital themes of the novel. Basically, this "past recovery" pertains to his compelling inner drive that makes Gatsby base his life on the central goal of getting Daisy back, but not JUST back, back as she was five years ago, with the dissumulation that the five years nor Tom Bucannon ever existed.
Gatsby had, in his mind (possibly even without direct comprehension), had made Daisy into nothing short of a Goddess, pure, without any defect or imperfection.
Sadly, dispite the reader's natural internal urge to want things to all be ok, things obviously turn bad for Gatsby. One cannot base their life on the past, it is nonredeemable. Sadly, besides Nick (who warns him in Chapter VI, as mentioned by luannw), Daisy has to brutally come out and directly say it to his face, not alone, but in front of the entire group (INCLUDING HER HUSBAND!): "Oh you want too much!" she cried to Gatsby. "I love you now- isn't that enough? I can't help what's past." She began to sob helplessly. One word summary of my feelings here: OUCH. The poor distraught man believed he could recover her, until minutes before his end, when he acknowledged that his heart that he had put out for her five years ago, was crushed completely that sweltering day before, leaving him with nothing.