What does the book's final quote mean? "Gatsby believed in the green light, the...ceaselessly into the past."
This quote is (obviously) told by Nick regarding Gatsby and his unrealistic dream for Daisy and him. But, that said, what is the best interpretation of the above quote?
With a tone of melancholy mixed with some awe at Gatsby's idealism, Nick reflects that Gatsby believed in a future which could yield to him his desires. However, this American Dream has eluded many an immigrant as well as many a parvenu of the Roaring Twenties. Moreover, the idealism of the early immigrants has been replaced by the materialism of the Jazz Age, with neither succeeding. But, with an optimism characteristic of Gatsby, Nick declares "tomorrow we will run faster, stretch out our arms farther"; in other words, the past can act as a model for the future. The green light again is a symbol of renewal. Nick closes hopefully,
And so we beat on, boats against the current, borne back ceaselessly into the past.
Nick revives the past as a renewed source of ideas for the future. The West from whence Nick has come has the more traditional values, while the East with its decadence, destruction, and dishonesty has corrupted the American Dream. So, by "stretching out" their "arms farther," and reaching to those values instilled in the West, people can restore the green light of hope to the future.