Question: Are papal encyclicals infallible?
Answer: We will have a more in depth article on papal infallibility in the
series "Our Sacred Faith," that will probably run in March or April.
But for the moment a few words are in order about papal documents.
Papal encyclicals are generally fairly long documents containing a variety of points about one or more issues. Some or all of these points are often about things that are beyond the scope of papal infallibility, dealing with things other than faith or morals, or being directed to some segment of the church. Traditionally, encyclicals are circular letters addressed only to the bishops of the Church. They tend to be discussions of some pressing matter at hand.
The only two "ex cathedra" papal pronouncements made during the last two centuries were contained in "apostolic constitutions," documents similar to an encyclical but addressed to no one and designed to make statements of law or fact, rather than to discuss an issue as do encyclicals. Yet, even these apostolic constitutions were not infallible in their entirety. Munificentissimus Deus defined the dogma of the Assumption of the Blessed Virgin in one sentence of a thirty-two page document.1 Ineffabilis Deus defined Mary's Immaculate Conception with one sentence in a twenty-three page document.2 Both contain a sentence detailing the penalty for refusing to believe the revealed doctrine. The remaining pages are devoted largely to outlining the history of the dogma in question and how it had been accepted by the faithful and the theologians over the centuries. While the single sentences of definition were guaranteed by the charism of infallibility, Pius XII or Pius IX could have made an error in one or more of their historical representations, since popes are not infallible in their teaching of history. And, at least in theory, they could have even made dogmatic or moral errors in parts of the document not directly connected to the ex cathedra pronouncement.
For a pronouncement to be an "ex cathedra" exercise of infallibility there must be no question as to the Pope's intention to make such a pronouncement, or about which phrase(s) contain the pronouncement. By its very nature the charism of infallibility would be useless if the faithful had to guess whether or not it was being employed. This requirement is reflected in the Code of Canon Law by the statement that "No doctrine is understood to be infallibly defined unless this is manifestly demonstrated."3 If informed and reasonable people can honestly hold that a pope did not signify this intention about a particular proposition, it cannot be an "ex cathedra" definition.
It should be noted, though, that Church documents may contain infallible teaching even though they make no "ex cathedra" pronouncements. In addition to the extraordinary magisterium, specifically expressed "ex cathedra" by popes and ecumenical councils, the Church also speaks infallibly through her ordinary magisterium, the teaching authority of popes and bishops who teach the unchanging Catholic Faith. Such pronouncements are more difficult to authenticate, in that they must be compared to, and found to agree with, the body of the Church's traditional teaching. Obviously, they must not contradict the ex cathedra teachings of popes and councils, or any of the teachings of immemorial tradition.
Two contrary examples by way of illustration:
(1) In Mortalium animos, even though he made no ex cathedra pronouncement, Pope Pius XI exercised the Church's Ordinary Magisterium in reaffirming the single and non-negotiable nature of God's truth. Pope Pius' teaching can be seen to be consistent with the authentic teachings of the Church about this subject, going all the way back to God's direct revelations in the Old Testament.4
(2) On the contrary, the recent encyclical Ut unum sint of Pope John Paul II gives out previously defined articles of dogma as though they were up for discussion.5 Obviously, this is not the Church's Magisterium contradicting itself, but represents the current Pope's own personal opinions and errors.
In summary, while a papal document may contain infallible truths, the entire document is not infallible. Infallible truths are discerned by their conformity to the unchanging teachings of the Church; unless, of course, they are clearly contained in an "ex cathedra" pronouncement, in which case such discernment becomes unnecessary.
1. Pope Pius XII, Munificentissimus Deus, November 1, 1950.
2. Pope Pius IX, Ineffabilis Deus, December 8, 1854. The page counts for both encyclicals refer to the St. Paul editions.
3. o.c. 1323; n.c. 749 ¹3.
4. e.g. Deuteronomy xx.
5. Pope John Paul II, Ut unum sint, #79, #95.