It is impossible to exclude David Hume from the list of significant philosophers of the Enlightenment. It was during the 17th and 18th centuries in particular that Enlightenment thought grew up in the wake of the centuries of religious warfare that devastated Europe and that flared up periodically even after the Peace of Westphalia legitimated sectarian Christianity. It was characterized by interrogation of traditional conceptions of many facets of human experience, and by the middle of the 18th century secular interrogation of religion was routine. Hume's place in this scheme of intellectual history has been characterized as "advanc[ing] theories on the origin of popular religious beliefs, grounding such notions in human psychology rather than in rational argument or divine revelation" (Feiser, 2006). That is important because of Hume's frequent recourse to man as the measure of all things, including God. The big picture of Hume's view of morality and religion is that they were social--that is, manmade--constructions that were subject to the same principles of logic as science, mathematics, politics, and other disciplines. For Hume it was also abundantly clear that God was a human construction, or that, at minimum, nobody could satisfactorily produce evidence for the existence of a supreme being. He develops his ideas in this area in Dialogues Concerning Natural Religion and elsewhere in his writings.
In the Dialogues, Hume posits through a conceit named Cleanthes a teleological argument for the existence of God, such that the order of the natural universe implies "the idea of a contriver" an "a conclusion surely [] in favour of design" of the cosmos (1990, p. 65). His rejoinder comes through a conceit named Philo, who explains that to infer from the natural cosmic order that God exists is to claim too much for infinity from the finite:
A very small part of this great system, during a very short time, is very i...