When Catholics say the Pope is infallible, what do they mean? To many non-Catholics this may seem a pompous and conceited claim. Surely popes are human beings and are thus capable of sinning like the rest of us? Indeed, there have been some popes who have behaved in less than exemplary manner. However, one must not confuse “infallibility” with “impeccability”.
Papal infallibility does not mean that a pope is sinless or he can never be wrong on matters of discipline. What it means is that when he is speaking ex cathedra in his capacity as successor of St Peter on matters of faith and morals, with the assistance of the Holy Spirit, his teachings are without error.
Papal infallibility was debated at the First Vatican Council, summoned by Pius XI in 1869. At the time, when people were demanding greater democracy and freedom, few Catholics rejected out of hand the notion that the Pope might speak infallibly. The question was how, if at all, that should be defined. The text agreed by the cardinals, known as ‘The Roman Pontiff’ read:
“...when he speaks ex cathedra (Latin for ‘from his throne’), that is, when, exercising the office of pastor and teacher of all Christians, he defines...a doctrine concerning faith and morals to be held by the whole Church, through the divine assistance promised to him in Saint Peter, is possessed of that infallibility with which the Divine Redeemer wished his Church to be endowed...and therefore such definitions of the Roman Pontiff are irreformable of themselves, and not from the consent of the Church.”
This is a doctrine which was implicit in the early Church, but the Church's understanding of it developed and became more clearly understood over time. The doctrine is implicit in these Petrine texts: John 21:15–17 ("Feed my sheep . . . "), Luke 22:32 ("I have prayed for you that your faith may not fail"), and Matthew 16:18 ("You are Peter . . . ").
According to the text, there are limits imposed around papal infallibility. Routine papal teaching is not infallible. The pope has to be speaking in a particular and solemn form. No mention is made, however, as to how such a definition should be arrived at. These restrictions have meant that since 1870 only one papal statement has been deemed infallible – the definition of the Virgin Mary’s assumption, body and soul into heaven, made in 1950.