Jean-Jacques Rousseau criticizes modern society because of its injustice. A society, whose members are motivated by self-love and relate to each other through market exchanges, implies a loss of equality and ever-increasing artificial inequalities. A social and political philosophy built upon such a society and mirroring its characteristics leads to a naturalization of the type of relationships and abuses this social organization implies. Such a social and political philosophy will focus on efficiency rather than justice. Rousseau’s alternative to such a society and to the political and social philosophy associated with it, is based upon an economy of abundance and sharing like the one he describes in Julie, or the New Heloise. In this economy, moral, economic, and affective bonds become one and give way to relationships that are just and non-envious. Each member takes part in the production of social wealth through labor and each one receives a share of this wealth that provides each member a place in society that such person neither wishes to leave or change. It is not an egalitarian organization but it is just, meaning, free of envy. This economy is only the starting point because justice can only be attained in the political sphere. This vision explains why Rousseau rejects the physiocrats’ science nouvelle as a social philosophy because economics deals with efficiency but says nothing about justice. This exploration shows the similarities and dissimilarities between Rousseau’s analysis and welfare economics, especially, common traits such as envy-free equilibria as found in the theory of economic justice. However, these similarities are limited because Rousseau’s project contains a radical transformation of the individual no longer guided by self-love.