In The Natural History of Religion, Hume has brought to completion an important part of that general science of human nature which he programatically anticipated and set out to achieve very early in the Treatise; i.e., to determine the origin of religion in human nature and delineate the manner in which it depends on its permanent structure. Particularly in the Dialogues, but also in the Treatise and the Enquiry Concerning Human Understanding,Hume examines its alleged rational justification. This is a good place from which to cast a glance at the path traversed and to what still remains ahead of us: First, I shall try to throw some light on the problematical opposition of "popular," "vulgar," or historical religion and "philosophical," "natural," or rational religion, that we may be able to answer the question of whether Hume was right in establishing such a great abyss between popular and philosophical religion. Second, I shall make a few brief observations and point out to several principles that will guide our examination of Hume's systematical criticism of the effort to provide a rational foundation for religious faith.