Although most of Kant’s readers understand the property of autonomy as being a property of rational wills, some, such as Thomas E. Hill, have held that Kant’s central idea is that of autonomy is a property, not primarily of wills, but of principles. The core idea is that Kant believed that all moral theories prior to his own went astray because they portrayed fundamental moral principles as appealing to the existing interests of those bound by them. By contrast, in Kant’s view moral principles m