“The idea of natural law holds that all people, whatever their ethnicity,
culture, or religion, can know the difference between good and evil, right and wrong. The idea, for example, of the Golden Rule—do unto others as you
would have them do unto you—is understood as a principle of moral conduct that everyone can know. While such beliefs are applied to different and changing conditions and problems, the core principles always apply.”
Samuel Gregg
Thomas Aquinas is credited as one of the greatest proponents of natural law. During his time in Cologne he was taught by Albertus Magnus. Magnus used the teachings of Aristotle in his mentorship of Thomas Aquinas.