Abstract
In his Treatise of Human Nature, Hume defines a belief as "a lively idea related to or associated with a present impression".1 He offers variations on this definition throughout the work, writing, for instance, that "belief is a more vivid and intense conception of an idea, proceeding from its relation to a present impression" and that his "general position" is "that an opinion or belief is nothing but a strong and lively idea deriv'd from a present impression related to it". Lest his readers misunderstand, Hume endeavours to clarify these notions of "vivacity" and "liveliness" by appealing to a cluster of other notions, such...