Separate from the question of whether our patients believe us as doctors is the question of whether we ourselves believe in our healing ‘performances’. Borrowing from Bernard Williams’ model of truth based on the two irreducible virtues of sincerity and accuracy, this article describes a spectrum of states of self-belief, from the quack who does not believe in his acts to the fanatic who does not ‘dis-believe’, with ranges of pious fraud and bad faith in between and on either side (...) of a variable range of justified self-belief. I describe how as practitioners we move and are moved up and down this range throughout our careers and as a result of the behaviors of others. The model provides the basis for a critique of the marketing efforts of industries related to medical practice. (shrink)