Answer: To show that the differences between the two areas of land is invisible from a distance.
Step-by-step explanation:
Symbolism is the use of indirect suggestions and symbolic images to express emotions, and states of mind.
In the book, the differences that existed between the East and West Egg was analysed. The East Egg was seen as the "old money" which were the people who were already wealthy and had some particular taates.
The West Egg denoted "new money" which were those who climbed up the social ladder and just got their improved financial status.
The way that symbolism is used in setting the novel was to show that the differences between the two areas of land is invisible from a distance.