The main theme in 'The Great Gatsby' is that one cannot relive the past, conveyed through various literary techniques.
'One can never relive the past' is the most clearly expressed theme in The Great Gatsby. Throughout the novel, F. Scott Fitzgerald uses various literary techniques like imagery and symbolism to convey the idea that attempting to recreate past moments is futile and often leads to tragedy, as seen in Jay Gatsby's pursuit of Daisy Buchanan.