Nature (symbol)
Perhaps the most important and most prevalent symbol in Rousseau's Second Discourse is nature itself. Rousseau's essay is about inequality: where it came from, and whether it is justified. Since his answer is that inequality is not justified, and comes from the artificial structures of civilization, "nature"—the opposite of the artificial—becomes a symbol for the good as a whole. When man is at one with nature, he is happy. The state of nature is an image of order: when man is hungry he gathers chestnuts; thirsty, he drinks at a stream; tired, he sleeps under the shade of a nearby tree. Nature, as a whole, stands in for all that is good, and all that we have left behind in civilization.
Transition from state of nature to civilization (allegory)
Rousseau explicitly says that his description of the state of nature is not based on some exclusive knowledge he has about what "actually happened"—since how could we know what happened before historical records were kept?—but on how, based on our current state, we can imagine the state of nature. This makes his description a kind of allegory, similar to what in the Christian bible is described as the expulsion from the garden of Eden and the fall of man.
When man leaves the state of nature, he enters into all of the hardship, unfreedom, and unhappiness of civilization—what Rousseau calls inequality. In this transition to civilization, man loses his innocence, develops artificial desires and forms of government, and falls under the curse of inequality. Rousseau's hope is that by realizing this, we may be able to get rid of the bad aspects of civilization, and consciously choose a political organization that would be closer to the state of nature.
The origin of private property (allegory)
Rousseau begins Part 2 of the Discourse with an allegory for the origin of private property. "The first man who, having enclosed off a piece of land, got the idea of saying 'This is mine' and found people simple enough to believe him was the true founder of civil society." This image of one man closing off a plot of land and declaring that it was his is an allegory for the emergence of the system of private property. Rousseau begins Part 2 with this allegory, because he argues that the emergence of private property was the origin of civilization—and thus the origin of inequality.
Origin of culture (allegory)
In the beginning of Part 2 of the Discourse, Rousseau speculates on the origin of culture. He describes a scene happening at the very beginning of the history of civilization, when small groups were just coming together. As they had begun to coordinate in simple tasks like hunting and rudimentary farming, they found themselves coming together and developing common practices, and even a simple language. In this scene, people are gathered around a tree, and they start performing for each other, singing and dancing. This is the origin of culture. But for Rousseau this is not necessarily a good thing: the people sing and dance in order to compete with each other, trying to prove that they are the best. So this scene is also an allegory for the emergence of inequality: people trying to one-up each other, measuring themselves against others and competing for attention and glory.
