Gatsby replies, "Why of course you can." If Gatsby cannot recreate the past, at least he can create an illusion that wipes out the five years he has been apart from Daisy. Well, actually Gatsby isn't successful but he really tries. Gatsby is a man lost in his own illusions. He is in love with ideas instead of realities. He loves the idea of Daisy and not Daisy herself. Gatsby thinks he can create his dream by throwing money at it. The problem with dreams fuelled by money is that they tendto evaporate no matter how much money is spent. There is no basis to his relationship with Daisy. Sure they had a fling so many years ago but it was not based on anything substantial. Gatsby is trying to recreate something that was never really there in the first place.