  Fidelity is the virtue of being disposed to fulfill promises and contracts. Hume has in mind promises made “at arm’s length” that parties undertake to promote their own interest, not affectionate exchanges of favors between friends. While he identifies the same circularity puzzle about the approved motive of fidelity that he tackles at length in connection with honesty, in the case of fidelity he concentrates on a different conundrum that arises with the misguided attempt to analyze fidelity as a non-conventional (natural) virtue. Unlike Hobbes and Locke, who help themselves to the concept of a promise or contract in their imagined state of nature, Hume argues that the performative utterance “I promise” would be unintelligible in the absence of background social conventions, and that the moral obligation of a promise is dependent upon such conventions as well.