Natural religion is the use of rationality and experience, as opposed to scripture and the supernatural, to endorse the existence of God. The utilization of such reason to explain the ways of God was prevalent in the 16th century, during the Protestant Reformation. As opposed to Roman Catholics, who primarily relied on tradition to affirm the existence of God, Protestants, and moreover radical Protestants, looked to primarily to natural religion and the Bible. Deists more ardently employed the notion of natural religion in the 18th century, asserting that the existence of God can be wholly corroborated by reason and physical observation.
Alexander Pope, in Essay on Man, seconds the use observation of general nature and to confirm God’s existence and explain God’s ways.
Ex. lines 17-22: “Say first, of God above, or man below, what can we reason, but from what we know…through worlds unnumbered though the god be known, ‘tis ours to trace him only in our own…”