Writing in an age that exalted reason, the Scottish-born skeptic David Hume was the first modern philosopher to emphasize the role of psychology, or "passion," in the formulation of moral judgments and ethical systems. Included in this edition of his writings is the entire text of An Enquiry Concerning the Principles of Morals and selections from other works such as A Treatise on Human Nature and Dialogues Concerning Natural Religion. Alasdair MacIntyre clarifies the relationship of Hume's intellect to his Calvinist background and cogently summarizes his importance to the development of moral philosophy.