R&L: The concept of natural law underpins the analysis in your latest book What We Can’t Not Know: A Guide. What is the natural law? Budziszewski: Our subject is called natural law because it has the qualities of all law. Law has rightly been defined as an ordinance of reason, for the common good, made by the one who has care of the community, and promulgated. Consider the natural law against murder. It is not an arbitrary whim, but a rule that the mind can grasp as right. It serves not some special interest, but the universal good. Its author...