In ethics, casuistry (// KAZ-ew-iss-tree) is a process of reasoning that seeks to resolve moral problems by extracting or extending abstract rules from a particular case, and reapplying those rules to new instances. This method occurs in applied ethics and jurisprudence. The term is also commonly used as a pejorative to criticise the use of clever but unsound reasoning, especially in relation to moral questions (as in sophistry). It is the "[s]tudy of cases of conscience and a method of solving conflicts of obligations by applying general principles of ethics, religion, and moral theology to particular and concrete cases of human conduct. This frequently demands an extensive knowledge of natural law and equity, civil law, ecclesiastical precepts, and an exceptional skill in interpreting these various norms of conduct." It remains a common tool for applied ethics.
According to the Online Etymological Dictionary, the term and its agent noun "casuist", appearing from about 1600, derive from the Latin noun casus, meaning "case", especially as referring to a "case of conscience". The same source says that "[e]ven in the earliest printed uses the sense was pejorative".
Casuistry dates from Aristotle (384–322 BC), yet the peak of casuistry was from 1550 to 1650, when the Society of Jesus used case-based reasoning, particularly in administering the Sacrament of Penance (or "confession"). The term became pejorative following Blaise Pascal's attack on the misuse of the method in his Provincial Letters (1656–57). The French mathematician, religious philosopher and Jansenist sympathiser attacked priests who used casuistic reasoning in confession to pacify wealthy church donors. Pascal charged that "remorseful" aristocrats could confess a sin one day, re-commit it the next, then generously donate to the church and return to re-confess their sin, confident that they were being assigned a penance in name only. These criticisms darkened casuistry's reputation in the following centuries. For example, the Oxford English Dictionary quotes a 1738 essay by Henry St. John, 1st Viscount Bolingbroke to the effect that casuistry "destroys, by distinctions and exceptions, all morality, and effaces the essential difference between right and wrong, good and evil"
The 20th century saw a revival of interest in casuistry. In their book The Abuse of Casuistry: A History of Moral Reasoning (1988), Albert Jonsen and Stephen Toulmin argue that it is not casuistry but its abuse that has been a problem; that, properly used, casuistry is powerful reasoning. Jonsen and Toulmin offer casuistry as a method for compromising the contradictory principles of moral absolutism and moral relativism. In addition, the ethical philosophies of utilitarianism (especially preference utilitarianism) and pragmatism have been identified as employing casuistic reasoning.[by whom?]
The casuistic method was popular among Catholic thinkers in the early modern period. Casuistic authors include Antonio Escobar y Mendoza, whose Summula casuum conscientiae (1627) enjoyed great success, Thomas Sanchez, Vincenzo Filliucci (Jesuit and penitentiary at St Peter's), Antonino Diana, Paul Laymann (Theologia Moralis, 1625), John Azor (Institutiones Morales, 1600), Etienne Bauny, Louis Cellot, Valerius Reginaldus, and Hermann Busembaum (d. 1668).
The progress of casuistry was interrupted toward the middle of the 17th century by the controversy which arose concerning the doctrine of probabilism, which effectively stated that one could choose to follow a "probable opinion", that is, supported by a theologian or another, even if it contradicted a more probable opinion or a quotation from one of the Fathers of the Church.
Certain kinds of casuistry were criticised by early Protestant theologians, because it was used to justify many of the abuses that they sought to reform. It was famously attacked by the Catholic and Jansenist philosopher Blaise Pascal, during the formulary controversy against the Jesuits, in his Provincial Letters as the use of rhetorics to justify moral laxity, which became identified by the public with Jesuitism; hence the everyday use of the term to mean complex and sophistic reasoning to justify moral laxity. By the mid-18th century, "casuistry" had become a synonym for attractive-sounding, but ultimately false, moral reasoning.
In 1679 Pope Innocent XI publicly condemned sixty-five of the more radical propositions (stricti mentalis), taken chiefly from the writings of Escobar, Suarez and other casuists as propositiones laxorum moralistarum and forbade anyone to teach them under penalty of excommunication. Despite this condemnation by a pope, both Catholicism and Protestantism permit the use of ambiguous statements in specific circumstances.
G. E. Moore dealt with casuistry in chapter 1.4 of his Principia Ethica, in which he claims that "the defects of casuistry are not defects of principle; no objection can be taken to its aim and object. It has failed only because it is far too difficult a subject to be treated adequately in our present state of knowledge". Furthermore, he asserted that "casuistry is the goal of ethical investigation. It cannot be safely attempted at the beginning of our studies, but only at the end".
Since the 1960s, applied ethics has revived the ideas of casuistry in applying moral reasoning to particular cases in law, bioethics, and business ethics, so casuistry's reputation is somewhat better now.
Pope Francis, a Jesuit, has criticized casuistry as "the practice of setting general laws on the basis of exceptional cases" in instances where a more holistic approach would be preferred.