From The Account Of Scalia's Remarks:
In the lunch session, he was asked a question about his views on “natural law.” He said, wittily, that he practices “American law.” Natural law might well be something appropriately taken into account by legislatures but not by courts. Whatever he might think as a Catholic citizen was one thing; his role as a judge was another.
The man was nothing if not consistent in his views.
Back in 2003, when I had a summer fellowship to study philosophy of law in Michigan, Justice Scalia joined us for three days during the program. One morning, the discussion turned to natural law and its relation to various recent Supreme Court decisions. Screwing up my courage (I was pretty intimidated just being in the same room with him), I asked him how, as a Roman Catholic, he reconciled Thomistic natural law theory (which situates civil law within the context of natural law, divine law, and eternal law) with his "originalism" (which, most generically, identifies civil law with black-letter law embedded in historical documents, legislation or case law). He hesitated less than a moment, and then said, "I don't."
He went on to discuss the famous (well, "famous" among those who study such things; probably nowhere else) debate between H. L. A. Hart and Lon Fuller over the relationship between law and morality. Hart was a chastened and somewhat reluctant legal positivist, who thought that law and morality had only an incidental connection, while Fuller thought law and morality were intimately and internally connected. Scalia was insistent: Hart got it exactly right. Morality, even of the natural law variety, should never be used as the foundation for a judicial decision, at least within the American context.
I have thought since that day that Scalia's "originalism" was species of thinly-disguised legal positivism, where any sort of moral "penumbra" surrounding the interpretation of American law was to circulate its light as far away from the courts as possible. It sounds like he held that position consistently to the end.
Tom Pearson