Complex sentence: In a series of books and articles dating from the mid- 1980s, Arkes has written on moral principles as true and necessary across cultures, their relation to constitional jurisprudence and natural law, and their challenge to moral relativism.
Split into simpler sentences: In a series of books and articles dating from the mid- 1980s, Arkes has written on moral principles, arguing that they are true and necessary across cultures. He has also dealt with their relation to constitional jurisprudence and natural law, and their challenge to moral relativism.