To "Beware Greeks bearing gifts," add "and canny Scots philosophers."

A distinctive quality of Hume’s writings on religion is that he sought gently to persuade rather than to confront. He was careful to observe the line that divided authors whose writings were disapproved of but tolerated and those whose books could not be permitted in one’s house. In order to avoid relegation to the latter class of writers, whose works would have fewer opportunities to persuade, it was enough to adopt the semblance of piety. It didn’t matter too much if some readers were wise to your game. 

Hume played this game most ingeniously in his posthumous Dialogues Concerning Natural Religion (1779), to which he was making alterations in the final weeks of his life. Several friends who saw the manuscript, including Adam Smith, thought that it went too far, and urged him not to let it be published even after his death, presumably for fear that it would ruin his reputation and make his other works less likely to be read. Seeking to reassure Smith, who he hoped would undertake its posthumous publication, Hume told him that nothing could be “more cautiously and more artfully written.” 

The manuscript was indeed so artfully written that people who are unfamiliar with eighteenth-century conventions of “theological lying,” as it has been called, still sometimes think that Hume ended up endorsing the idea that design in nature points to the existence of a God.* In his Dialogues, which were closely modeled on a work by Cicero, Hume expanded and refined the criticisms he had earlier attributed to a fictitious Epicurean friend, this time putting them in the mouth of a character named Philo, whom the narrator of the Dialogues presents as having lost the debate. Philo concludes by allowing that “the cause or causes of order in the universe probably bear some remote analogy to human intelligence,” which sounds respectably like an endorsement of theism. But careful readers will notice that the analogy conceded by Philo is demonstrated to be so remote that it is in fact consistent with atheism. Hume once remarked in a letter to the Comtesse de Boufflers that poor Rousseau had got into trouble because he neglected to “throw any veil over his sentiments.” This was not a mistake Hume was inclined to make, even posthumously...