David Hume listed virtues into two categories in his work "A Treatise of Human Nature" as artificial virtues and natural virtues. Hume noted in the Treatise that courage is a natural virtue. In the Treatise's section "Of Pride and Humility, Their Objects and Causes", Hume clearly stated courage is a cause of pride: "Every valuable quality of the mind, whether of the imagination, judgment, memory or disposition; wit, good-sense, learning, courage, justice, integrity; all these are the cause of pride; and their opposites of humility".