Adam Smith came home to Kirkcaldy in the spring of 1767, at forty-three, having resigned a professorship at Glasgow to travel through France as tutor to a young duke. He had met Voltaire at Ferney and Quesnay and Turgot in Paris. He came back to a small port town with a life pension and a manuscript, and stayed roughly six years.⁴ The letters from those years are the letters of a man in difficulty.

Episode 12 of Self-Evident opens Arc Four and the Scottish arc. It begins with the conditions: a kingdom that lost Darien and then argued itself into a union it did not agree about, a Kirk that put a schoolmaster in nearly every lowland parish because Presbyterian doctrine required ordinary people to read Scripture themselves, and that in the same generation urged the vigorous execution of the law against a twenty-year-old student named Thomas Aikenhead, hanged for blasphemy

The lesson of Worms was not the lesson Luther meant to give. He meant to defend the Word of God against a corrupt Church. He taught, instead, that no earthly authority is beyond the judgment of a conscience answerable to something higher — and that lesson, once learned, could not be confined to the Church.