The Promised Infallibility

The issue of infallibility is thus defined:

890 The mission of the Magisterium is linked to the definitive nature of the covenant established by God with his people in Christ. It is this Magisterium's task to preserve God's people from deviations and defections and to guarantee them the objective possibility of professing the true faith without error. Thus, the pastoral duty of the Magisterium is aimed at seeing to it that the People of God abides in the truth that liberates. To fulfill this service, Christ endowed the Church's shepherds with the charism of infallibility in matters of faith and morals. The exercise of this charism takes several forms:

891 "The Roman Pontiff, head of the college of bishops, enjoys this infallibility in virtue of his office, when, as supreme pastor and teacher of all the faithful - who confirms his brethren in the faith he proclaims by a definitive act a doctrine pertaining to faith or morals. . . . The infallibility promised to the Church is also present in the body of bishops when, together with Peter's successor, they exercise the supreme Magisterium," above all in an Ecumenical Council. When the Church through its supreme Magisterium proposes a doctrine "for belief as being divinely revealed," and as the teaching of Christ, the definitions "must be adhered to with the obedience of faith." This infallibility extends as far as the deposit of divine Revelation itself.

The doctrine of infallibility operates on two levels: definition and inclusiveness. The definition of infallibility is a negative definition: being preserved from "deviations and defections", teaching doctrine "without error". For instance, to say "the sun is a star" is to say an infallible statement, a statement that is error-free. The statement "the sun is big" can also be seen as infallible, without error, since the sun is indeed big under many standards of measurement. Even though the sun may not look big when seen from earth, or when compared to even larger celestial objects, to say "the sun is big" is not to say something in error. Thus, an infallible statement is true, but an infallible statement is not necessarily the last word on the subject.

And that leads to the second level of infallibility: inclusiveness. An infallible statement, though without error, is not exclusive, or exhaustive. An infallible statement may be without error, but being without error is different from being an exhaustive statement that says everything that can be said about the subject. To say "humans are animals" may be without error, but it doesn't say everything that there is to say about humans, or animals, for that matter. An infallible statement need not be the last word on an issue.

So, the Church's doctrine of the infallibility of, say, the Roman Pontiff, is restricted to issues concerning "matters of faith and morals". Whatever the Pontiff says about faith and morals need not be infallible, though. Only certain statements concerning faith and morals, under defined conditions, are considered infallible. And even these infallible statements, though without error, are not the final words on the subject.