Infallibility: “The Roman Pontiff, when he speaks ex cathedra—that is, when, in discharge of the office of Pastor and Doctor of all Christians, by virtue of his supreme Apostolic authority he defines a doctrine regarding Faith or Morals to be held by the Universal Church—by the Divine assistance promised to him in Blessed Peter, is possessed of that Infallibility with which the Divine Redeemer willed that His Church should be endowed for defining doctrine regarding Faith or Morals; and therefore such definitions of the Roman Pontiff are irreformable of themselves and not from the consent of the Church.”
II. The person in whom the Infallibility is vested is the Roman Pontiff speaking ex cathedra; that is to say, exercising the highest doctrinal authority inherent in the Apostolic See. Whenever the Pope speaks as Supreme Teacher of the Church, he speaks ex cathedra; nor is there any other ex cathedra teaching besides his. The definition therefore leaves no room for the sophistical distinction made by the Gallicans between the See and its occupant (Sedes, Sedens). An ex cathedra judgment is also declared to be supreme and universally binding. Its subject-matter is “doctrine concerning Faith or Morals;” that is, all and only such points of doctrine as are or may be proposed for the belief of the Faithful. The form of the ex cathedra judgment is the exercise of the Apostolic power with intent to bind all the Faithful in the unity of the Faith.
The nature and extent of the Infallibility of the Pope are also contained in the definition. This Infallibility is the result of a Divine assistance. It differs both from Revelation and Inspiration. It does not involve the manifestation of any new doctrine, or the impulse to write down what God reveals. It supposes, on the contrary, an investigation of
