This is the text of a contribution to a seminar on Natural Law held under the chairmanship of Alexander Konovalov, Minister of Justice of the Russian Federation, at the St. Petersburg International Legal Forum in May 2015. The seminar contributors were invited to consider, in a 12-minute presentation, one or more of seven questions listed by the organisers. This contribution addressed each of them. They concern the foundations of values, of notions of right and wrong, and of law, and ask whether those foundations have a rational universality that can be accepted independently of any society’s conventional beliefs or the tenets of any religious faith. They extend, finally, into a question about public international law.