Smith was certainly a Theist, his writings leave no doubt of that, but he most probably discarded the Christian miracles; and if Douglas's book is addressed to his particular position, discarded them on the ground that there is no possible criterion for distinguishing true miracles from false, and enabling you to accept those of Christianity if you reject those of profane history. The Earl of Buchan, apostrophising Smith, asks, "Oh, venerable and worthy man, why was you not a Christian?" and tries to let his old professor down as gently as possible by suggesting that the reason lay in the warmth of his heart, which always made him express strongly the opinions of his friends, and carried him in this instance into sympathy with those of David Hume. That is obviously a lame conclusion, because Smith's friendship for Hume never made him a Tory, nor even on the point of religion were his opinions identical with those of Hume; but Lord Buchan's words may be quoted as an observation by an acute man of a feature in Smith's character not without biographical interest. "Had he (Smith) been a friend of the worthy ingenious Horrox," says his lordship, "he would have believed that the moon sometimes disappeared in a clear sky without the interposition of a cloud, or of another truly honest and respectable man, that a professor of mathematics at Upsala had a tail of six inches long to his rump."[95] In 1756 the literary circle in Edinburgh was much excited by the performance of John Home's tragedy of _Douglas_. Smith was not present at that performance; but he is stated by Henry Mackenzie, in his _Life of John Home_, to have been present at some of the previous rehearsals of the play, and at any rate he was deeply interested in it; and Hume, as soon as he hears of the continued success of the play in London, hastens to communicate the welcome news to his friend in Glasgow, with whom he was in correspondence about his own historical plans. Smith seems to have been advising him, instead of following up his _History of the Stewarts_ by the history of succeeding periods, to go back and write the history of the period before the Stewarts. After mentioning John Home, Hume proceeds: "I can now give you the satisfaction of hearing that the play, though not near so well acted in Covent Garden as in this place, is likely to be very successful. Its great intrinsic merit breaks through all obstacles. When it shall be printed (which shall be soon) I am persuaded it will be esteemed the best, and by French critics the only tragedy of our language!... "Did you ever hear of such madness and folly as our clergy have lately fallen into? For my part, I expect that the next Assembly will very solemnly pronounce the sentence of excommunication against me, but I do not apprehend it to be a matter of any consequence; what do you think?