  Rousseau repeatedly claims that a single idea is at the centre of his world view, namely, that human beings are good by nature but are rendered corrupt by society. Unfortunately, despite the alleged centrality of this claim, it is difficult to give it a clear and plausible interpretation. One obvious problem is present from the start: since society, the alleged agent of corruption, is composed entirely of naturally good human beings, how can evil ever get a foothold? It is also difficult to see what “natural goodness” might be. In various places Rousseau clearly states that morality is not a natural feature of human life, so in whatever sense it is that human beings are good by nature, it is not the moral sense that the casual reader would ordinarily assume. In order, therefore, to address this puzzling central claim, it is best to look first at the details of Rousseau’s moral psychology, especially as developed in the Discourse on the Origins of Inequality and in Emile.