ABSTRACT
Hume's sensible knave observes the general rule, and takes advantage of all the exceptions. He enquiring the Principles of Morals, Hume comments: a sensible knave, in particular incidents, may think that an act of iniquity or infidelity will make a considerable addition to his fortune, without causing any considerable breach in the social union and confederacy. Knaves consciously treat themselves as important in ways that contradict the laws of an identity to which they are reflectively committed, if they are to have any values namely, their identity as just one reflective animal among others. The knave's underlying maxim is to better his own circumstances by safe deceit, in the case of lying promises, will reflect his cautious self-love. The formal part of Kant's story fails: the knave's maxim survives the contradiction test. On the material side, Kant's postulation of humanity or rational nature as a necessary end which demands our respect makes an assumption that needs to be vindicated.
