Three Sixteenth-Century Thomist Solutions to the Problem of a Heretical Pope: Cajetan, Cano, and Bellarmine

ANY CHRISTIAN ECCLESIOLOGY that recognizes an external magisterial authority has to reckon with the question, what happens if that authority tries to teach definitively something that is contrary to the faith—in other words, heresy? Theoretically, the question is of perennial interest; historically, it occasionally has been a very lively one.¹

In Catholic theology the question tends to be centered on the pope (though it could just as easily be posed of a council). The possibility of papal heresy was commonly treated in medieval reflections on canon law and ecclesiology and was generally affirmed in the Thomist school. In the sixteenth century, three Thomist theologians, Cajetan, O.P. (1468–1534), Melchior Cano, O.P. (1509–60), and St. Robert Bellarmine, S.J. (1542–1621), took up the question in the context of conciliarism and the Reformation. This article will examine the views of these three theologians about which kinds of papal teachings are subject to error and which are not, and about whether and how the Church could depose a heretical pope. To this end, this article will treat each theologian’s understanding of papal infallibility, since each of the authors thought that there are conditions under which God necessarily protects the pope from teaching error. It also will examine their understanding of the limits of papal infallibility. This article will treat the three authors’ assessments of popes who have been accused of heresy in order better to understand their theory of the papa haereticus, but it will prescind from analyzing whether their historical judgment is correct. Finally, it will treat whether and under what conditions a pope could be a heretic and the process by which the Church can be freed from a heretical pope.

I. Theological Background

Gratian’s Concordia discordantium canonum appeared around A.D. 1140, and it was a kind of medieval “Denzinger” containing a collection of authoritative texts.² Gratian’s work presents a series of texts concerned with the limits of papal authority. Perhaps the best known is the following canon, known by its incipit, Si Papa, written by St. Boniface, apostle to the Germans and a martyr:

If the Pope, negligent of his own and of his brothers’ salvation, is discovered slack and remiss in his deeds, and silent, moreover, in the cause of good when he should speak, which last is the more harmful to himself and to others, then no less does he lead countless people along with him in a throng to their first slave of hell, he himself to be beaten with many stripes together with Satan for all eternity. Here no mortal presumes to rebuke his faults, because he, the one who is to judge all, is to be judged by none, unless he be found straying from the faith.³

Gratian had both received and transmitted a basic tension in the Church’s doctrine of the papal magisterium. This tension can be seen in the two propositions: “the one who is to judge all, is to be judged by none,” and “unless he be found straying from the faith.”⁴ Gratian also holds that a person does not fall into heresy by simply holding erroneous doctrine. One has to hold this error pertinaciously after being corrected.⁵ Gratian not only presents papal heresy as theoretically possible, but he seems to have thought that it had occurred and gives the unhistorical example of Pope Anastasius II (r. 496–98).⁶ While Si Papa is clear that the pope could be judged for a deviation from the faith, it also leaves much unsaid. It does not sanction any particular method for judging a pope for heresy, nor who may judge the pope, nor when the pope may be judged (e.g., after a rebuke), nor in what condition a pope finds himself when judged (e.g., is he still the pope or is he a heretic who was deposed ipso facto?).

Si Papa ensured that the issue of papal heresy was a common theme in the canonistic...