Briefly looking at the “Notice About the Notes:”
“I have added some notes to this work in accordance with my lazy habit of working on this and that. These notes wander sometimes so far from the subject that it is not good to read them with the text. So I have shifted them to the end of the Discourse, in which I have tried to follow as best I can the most direct route. Those who have the courage to start again will be able to entertain themselves a second time by beating the bushes and striving to move through the notes. If other people do not read them at all, there will be little harm done.”
I would simply observe that Rousseau believed the Second Discourse could be understood only with great effort, and that here with this little note, he divides his readers: those with the courage to begin again can amuse themselves. So, something in the Second Discourse requires courage to face again and to think through, but one can also amuse oneself in the discovery.
Rousseau’s books typically begin with a rhetorical flourish:
In Emile we get: “Everything is good as it leaves the hands of the Author of things; everything degenerates in the hands of man.”
In his Confessions we get: “I am undertaking a work which has no example, and whose execution will have no imitator.”
In The Social Contract we get: “Man is born free, and everywhere he is in chains.”