John Coughlin’s comparative and interdisciplinary scholarship focuses on diverse legal systems and the understanding of the human person and community that underpin them. In this regard, his two books compare the canon law of the Catholic Church with secular legal theory. In CANON LAW: A Comparative Study with Anglo-American Legal Theory (Oxford University Press 2011), Coughlin inquires how antinomian and legalistic tendencies in canon law impact the rule of law. Chapter 1 offers an overview of canon law as the “home system” in this comparative study. The remaining chapters discuss antinomian and legalistic approaches to the rule of law in light of three specific issues: the sexual abuse crisis, the ownership of church property, and the denial of Holy Communion to Catholic public officials. Although the three issues arise in the context of the United States, they pertain to broader theoretical issues about antinomianism, legalism, and the rule of law. Throughout the study, Anglo-American legal theory serves to clarify these broader issues in canon law. Coughlin concludes the book by asking, from the perspective of legal positivism, whether canon law may be considered as law, whether it constitutes a legal system, and whether it represents the rule of law.

With LAW, PERSON, AND COMMUNITY: Theological, Philosophical, and Comparative Perspectives on Canon Law (Oxford University Press 2012), Coughlin continues the exploration of the theoretical foundations of canon law in comparison to secular law. This book brings to light the anthropological foundation of religious law, the relation between law and theology, the function of natural law in religious law, and equity in religious law. The book also highlights development in the law, religious authority (papal power), fundamental rights, the emergence of personalism in the canon law of marriage, and the relation between church and state. The comparison of a classical religious system of law and legal positivism discloses that each approach to law functions with a different concept of reason and understanding of the human person. It raises the epistemological questions of the fact/value distinction and of what counts as a reason. This book concludes with observations about the interrelation of law, person, and community.

Both books pose the fundamental question: “What is law?” Professor Coughlin’s comparative and interdisciplinary method enables critical analysis of religious and secular approaches to law. It proffers that a religious system of law such as canon law might serve as a conversation partner in the contemporary discussion about the nature of law. Coughlin’s on-going scholarly project transcends the parameters of canon law and studies the contributions of Buddhism, Confucianism, Hinduism, Islam, and Judaism to understanding what is law.