A common Protestant and secularist canard is that Catholics believe the bishop of Rome enjoys a kind of plenary infallibility, i.e., that Catholics believe the pope can never make a mistake, either at all or in the course of performing his official duties. The slightly more sophisticated version of this slander is that Catholics believe the pope will never err in his official teaching. Up until just a few years ago, every educated Catholic worth his salt knew how to respond to this misrepresentation of Catholic doctrine: He would recite the dogmatic definition of papal infallibility promulgated by the First Vatican Council:

[F]aithfully adhering to the tradition received from the beginning of the Christian faith . . . we teach and define as a divinely revealed dogma that when the Roman pontiff speaks ex cathedra, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole Church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed His Church to enjoy in defining doctrine concerning faith or morals.

This essay is not concerned with defending this dogma of the Catholic Christian religion, only to note what it claims and what it does not. As can clearly be seen, the Catholic Church does not teach that the pope —the Roman pontiff — possesses the Church’s infallibility when he says just anything or publishes just any teaching. Rather, he only exercises the Church’s infallibility “when, [1] in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, [2] he defines [3] a doctrine concerning faith or morals [4] to be held by the whole Church.” In other words, orthodox Catholics believe the bishop of Rome’s teaching is only assured infallibility by God when four conditions are met. When any of these four conditions are absent, the pope’s teaching, just like any other Catholic’s, may contain error. . . .

Catch the rest of this essay on Eric Giunta’s blog, Laboravi Sustinens!