In "The Great Gatsby," Gatsby's belief in repeating the past stems from his fixation on an idealized history with Daisy. As Nick, the narrator, reflects on the fleeting nature of time symbolized by a green light, he wrestles with the urge to caution Gatsby about the impossibility of his dreams, but hesitates due to empathy and fear of shattering Gatsby's illusions.
Jay Gatsby, the enigmatic protagonist in F. Scott Fitzgerald's "The Great Gatsby," is certain that it is possible to repeat the past because he is deeply fixated on a romanticized version of his personal history. Gatsby's unshakable belief is rooted in his love for Daisy Buchanan, whom he met and fell in love with before going off to fight in World War I. He believes that by recreating the past and rekindling his romance with Daisy, he can erase the years that separated them and restore the idealized moments he shared with her.
As Gatsby speaks about the past, Nick Carraway, the narrator, is reminded of the inherent fragility of time and the impossibility of turning back its relentless march. The reference to a green light at the end of Daisy's dock symbolizes Gatsby's unreachable dream and the illusion of recapturing the past.
Nick is compelled to tell Gatsby the futility of his pursuit, cautioning him against the unrealistic nature of his ambitions. However, Nick finds himself unable to articulate these thoughts, perhaps recognizing the depth of Gatsby's emotional investment and fearing the impact of shattering Gatsby's illusions. Nick understands the tragic gap between Gatsby's dreams and reality but is hesitant to confront him with the harsh truth, leading to his silence in the face of Gatsby's unwavering conviction.