Infallibility, freedom from all error in the past and from all possibility of error in the future as claimed by the Church of Rome. This claim extends to all matters of faith, morals, and discipline in the Church, and is based on an interpretation of Matt. xvi. 18, xxviii. 19; Eph. iv. 11-16, and other passages. It is held that the Church is incapable of embracing any false doctrine from whatever quarter suggested, and that she is guided by the Divine Spirit in actively opposing heresy, in teaching all necessary truth, and in deciding all relative matters of controversy. Infallibility is not claimed in connection with matters of fact, science, or general opinion. The seat of infallibility has been much disputed even in the Roman Catholic Church itself, and the infallibility of the Pope was only decreed so recently as the Vatican Council in 1870. It was always agreed that where the Pope and Bishops were unanimous they were infallible, and their unanimity might be expressed either in a general council, or in a decree of a local council tacitly accepted by the Pope and the rest of the Church, or even in a decree of the Pope alone if the bishops either expressly or tacitly affirmed it. But the Vatican Council decided "that when the Roman Pontiff speaks ex cathedrâ—that is, when he, using his office as pastor and doctor of all Christians, in virtue of his apostolic office, defines a doctrine of faith and morals to be held by the whole Church—he by the Divine assistance, promised to him by the blessed Peter, possesses that infallibility with which the Divine Redeemer was pleased to invest His Church in the definition of doctrine in faith or morals, and that therefore such definitions of the Roman Pontiff are irreformable in their own nature and not because of the consent of the Church." The Greek Church puts forward a moderate claim to inerrancy, holding that as a matter of fact those councils which she regards as oecumenical have not erred in their decrees affecting faith and morals.

In*fal`li*bil"i*ty (?), n. [Cf. F. infaillibilité.] The quality or state of being infallible, or exempt from error; inerrability.

Infallibility is the highest perfection of the knowing faculty.

Tillotson.

Papal infallibility(R. C. Ch.), the dogma that the pope can not, when acting in his official character of supreme pontiff, err in defining a doctrine of Christian faith or rule of morals, to be held by the church. This was decreed by the Ecumenical Council at the Vatican, July 18, 1870.