Excerpts from articles on "casuistry" by Nigel Biggar (Encyclopedia of Christian Theology) and Hugo Adam Bedau (Encyclopedia of Ethics).


The term is derived from casus, the Latin for "case," and means the study of individual "cases of conscience" in which either no or more than one settled moral principle applies. More broadly, casuistry is the use of the "method of cases" in the attempt to bring ethical reflections to bear on problems requiring the decision and action of some agent. A casuist is one who is trained to provide such counsel. Accordingly, casuistry is a branch of applied ethics.Since the seventeenth century, however, the term has often been used in a derogatory sense, as though casuistry were a species of sophistical reasoning by means of which almost any conduct could apparently be deemed permissible, provided only that one is ingenious enough in exploiting exceptions and special circumstances.

Aristotelian Background

Casuistry is a natural outgrowth of three features of Aristotelian ethics. First, Aristotle (384–322 b.c.e.) took it for granted that persons have a grasp of the principles of right conduct, based on their socialization as members of a human community. Aristotle also argued that it is impossible to secure theoretical precision in practical matters, and so ethical reasoning should not aspire to the rigor appropriate to a true science. Finally, practical wisdom (Aristotelian phronesis) is essential to right conduct; it can be obtained only by critical reflection on actual experience in confronting the diverse problems that human life presents.

Ciceronian Rhetoric

Casuistry (though not under that name) was taught for centuries as part of Greco-Roman rhetoric. A standard exercise required the student to propose and defend a solution to a practical problem by means of arguments and counter arguments in which various moral principles and solutions to analogous cases would be integrated for maximum persuasive effect. Cicero's (106–43 b.c.e.) De officiis (c. 44 b.c.e.) provided later generations with a partial catalog of famous cases in which either a conflict of duties or a conflict between duty and expediency needed to be resolved. Thus, later casuistry can be seen as a systematic approach to ethical problems derived from Ciceronian rhetoric.

Legal and Clerical Influences

a) Judaism. It is logical that in Judaism, where the Law is so important, there is a very rich jurisprudence and casuistry, collected in the tradition of the scribes and rabbis and found both in Scripture (e.g., Ex 20:1–23:19) and in the Midrash (especially the Halakha). Weighing relevant principles, arguing from paradigm cases, distinguishing apparently contrary conclusions in prior cases—all are familiar methods in the resolution of disputes in Talmudic commentary and interpretation.

b) The New Testament. It can be said that Jesus and Paul belong to some degree to this tradition. On several occasions in the Gospels, Jesus is seen making an interpretation of the requirements of the Law, for example, with respect to divorce (Mk 10:2–12; Mt 19:1–12) or the sabbath (Mk 2:23–28). As for Paul, in 1 Corinthians 8, he discusses the question of whether it is legitimate to eat the meat offered in sacrifice to idols. Paul and Jesus, however, criticized certain aspects of the casuistry of their time, either because it lost sight of the true intent of the law (Mk 2:27), because it was obsessed with the letter (1 Cor 8), or because it invented ingenious ways of avoiding true moral requirements (Mk 7:9–13).

Among Christians, the need to reconcile the Mosaic law with the examples and counsels in the Gospels in order to provide guidance for daily life made the development of casuistical reasoning by the clergy all but inevitable. These legal and pastoral elements were combined in the development of canon law and penitential discipline during the Middle Ages.

The Heyday of Casuistry

From 1200 through 1650, the teaching and practice of casuistry flourished in Europe. With the founding of the Society of Jesus (1534), casuistry dominated pastoral (moral) theology. Treatises in which hundreds (even thousands) of cases were presented and discussed became commonplace. One of the most influential was the Enchiridion (1556) of Martin Navarrus. In 1600, the Jesuit Juan Azor published his Institutionum Moralium, nearly 4,000 pages long, in which he declared "all questions of conscience are briefly treated." The monumental Resolutiones morales by Antonius Diana (1586–1663), "the Prince of Casuists," discussed some 20,000 cases in ten volumes (published 1629–1659).

During this time the place of casuistry in Catholicism remained stable. In reaction against what it saw as the moral laxity of Protestantism, the Catholicism of the Counter-Reformation placed even greater emphasis on moral law. From that period until World War II, its moral theology took the form of manuals of casuistry, the model for which had been provided by Jean Azor (1536–1603) in his Institutiones morales of 1600–1601. The most influential of these manuals was the Theologia moralis (1748) of Alphonsus Liguori, who has been the patron saint of confessors and moral theologians since 1950, which clearly indicates the permanence of his authority. Alphonsus Liguori managed to put an end to the debate, which had raged in the 17th century and continued in the 18th, on the possibility of legitimately straying from the moral law. In the middle of the 17th century, probabilism, a theory formulated by Bartolomeo de Medina (1527–80), was widespread in the Catholic Church. According to this theory, conduct not in conformity with the law but that can with reason be morally defended (i.e., conduct that is "probable") is morally acceptable, even if there are stronger arguments in favor of different conduct. "Probability" can be "intrinsic" and consist of the strength of the argument or "extrinsic" and consist of the prestige of the authority that can be invoked in its favor. The Jansenists were horrified by a doctrine that could justify the loosest conduct, sometimes on the basis of a single authority. They were on the contrary advocates of an austere form of "tutiorism." This holds that in case of doubt one must make the surest (Latin tutior) decision, and in its austere form it considers that the safest course is to act in conformity with the law. On three occasions (1665, 1666, 1679), the Church condemned the laxity of the conclusions of certain probabilist arguments, and by the late 17th century, laxism had practically disappeared. But in 1690, Rome also condemned the extreme forms of tutiorism. The continuing debate between the more moderate forms of these positions was resolved by the "equiprobabilism" of Alphonsus Ligouri. According to this, one may prefer a probable opinion over the law, but only in cases in which opinions for and against have the same force.

The Decline of Casuistry

The disappearance of penitential discipline under Protestantism, combined with the criticism of laxism from within the Roman church itself, weakened the practice and authority of casuistry. But the truly fatal blow was delivered by Blaise Pascal (1623–1662) in his Lettres Provinciales (1656–57). As a Jansenist, convinced that the path of Christian rectitude involved strict compliance with the pure spirit of the Gospels, Pascal was hostile to the probabilist casuistry taught by the more worldly Jesuits. Writing anonymously, he mocked it unmercifully and exposed to ridicule the moral laxity of its diverse counsels.

However unfair a caricature of the actual methods and principles of casuistry Pascal's attack may have been, it succeeded in discrediting the entire practice. Henceforth, little more than faint echoes of casuistry would be found in the ethical writings of the leading philosophers outside the clerical tradition, such as Kant (1724–1804) and J. S. Mill (1806–1873). By the end of the nineteenth century, with ethical pluralism and intuitionism on the defensive generally, Henry Sidgwick (1838–1900) could write 500 pages on The Methods of Ethics and dismiss casuistry in a sentence. However, thanks to the growing importance in the 1970s of applied ethics and of professional ethics in particular, a "new casuistry" has appeared in which the old "method of cases" has been revived and modified.