Probabilism, Decline, Bibliography
From the Latin casūs (cases), casuistry is a method of practical reasoning that aims to identify the scope and force of moral obligations in the varied contexts of human action. While the golden era of casuistry belongs to the period 1450–1660, its origins as an intellectual outlook on moral decision-making can be traced back to ancient philosophy and to the legal traditions of medieval Europe. Aristotle, for instance, stressed the importance of an irreducibly practical method of moral reasoning that would be attentive to "the particulars" (ta kath' hekasta) of cases. The Stoics also sought to provide detailed reasons as to how universal principles could be applied to particular cases. In addition to this, they bequeathed the idea of a natural law and a set of stock "casuistical examples," such as "Murderer at the Door" and "the Merchant of Rhodes," which would command the attention of European moralists for many centuries.
The development of a casuistical ethics would await the emergence of medieval canon law as set down by Gratian of Bologna (d. before 1159) and his interpreters, as well as the analysis by Scholastic theologians of the problems of human life as they affected the Christian conscience. Alongside canon lawyers, Scholastic thinkers considered cases of conscience (casūs conscientiae) that required a sensitive analysis of their conflicting options. The casuistical tendencies inherent in medieval theology and law were further fortified by the stipulation of the Fourth Lateran Council (1215) that all members of the faithful undergo auricular confession before a priest at least once a year. As a result of this development, medieval thought witnessed the advancement of a new genre of theological writing: the summa confessorum. These tracts were written for pastors hearing confession and contain detailed recommendations on the types of sin as well as their appropriate penitential tariffs. Well-known fifteenth-century manuals written by Angelo Carletti di Chivasso (1411–1495) and Sylvester Mazzolini (1460–1523) helped to condition the method adopted by later casuistical treatises.
Casuistry came of age in the sixteenth century. Building on the legacy of medieval moral thought, it sought to address the complexities of early modern life by means of restating the verities of the Christian tradition, while developing new theories of moral decision-making. There is a great diversity among the varieties of casuistical writing. On the one hand, there are speculative treatments of the practical problems of natural law and moral theology. An example of this tendency can be witnessed in the writings of Jesuit theologians Gabriel Vásquez (1549 or 1551–1604), Francisco Suárez (1548–1617), and Leonardus Lessius (1554–1623). This, however, might be said to contrast with other types of casuistical writing, where the intention of the author is wholly pastoral. Here the aim was to provide pithy and more accessible treatments of the basic problems of conscience, either for the benefit of those involved in the training of priests—a need that became pressing with the establishment of seminaries after the Council of Trent (1545–1563)—or else for priests engaged in parochial work or missionary activity. Examples of this type of manual can be found in the writings of the Jesuits Franciscus Toletus (1534–1596) and Antonio Escobar y Mendoza (1589–1669).