David Hume's An Enquiry Concerning Human Understanding was a simplification of an earlier effort, Hume was disappointed with the reception of the Treatise of Human Nature He felt that if "fell dead-born from the press," as he put it, and so tried again to disseminate his ideas to the public by writing a shorter and more polemical work. The Enquiry dispensed with much of the material from the Treatise, in favor of clarifying and emphasizing its most important aspects. This book was highly influential, Immanuel Kant points to it as the book which woke him from his "dogmatic slumber." The...

David Hume's An Enquiry Concerning the Principles of Morals is often called Hume's second Enquiry. His approach in the second Enquiry is largely an empirical one. Instead of beginning his moral inquiry with questions of how morality ought to operate, he purports to investigate primarily how we actually do make moral judgments. Of this work Hume said, "of all my writings, historical, philosophical, or literary, incomparably the best."

Dialogues Concerning Natural Religion is a philosophical work written by the Scottish philosopher David Hume. Through dialogue, three fictional characters named Demea, Philo, and Cleanthes debate the nature of God's existence. While all three agree that a god exists, they differ sharply in opinion on God's nature or attributes and how, or if, humankind can come to knowledge of a deity. In the Dialogues, Hume's characters debate a number of arguments for the existence of God, and arguments whose proponents believe through which we may come to know the nature of God. Such topics debated include...