There is little doubt that Papal Infallibility has been badly misunderstood. Dissenters from Catholic Teaching such as Hans Küng, Rosemary Radford Ruether, Charles Curran, Richard P. McBrien, and that claque of dissidents who write and distribute the National Catholic Reporter have attacked and distorted the doctrine. Poorly catechized Catholics betray great confusion concerning it, and find themselves helpless to defend doctrines of the Church under the present assault, that is to say, its teaching on contraception, abortion, homosexuality, and women's ordination.
Now, the Catholic Church has always held that the Church in general, and the Successor of Peter in particular, is infallible, i.e. incapable of error in defining doctrines which touch on faith and morals. The Church possesses the property of Infallibility because it is the Body and Bride of Jesus Christ, and thus incapable of teaching error to the faithful, in the name of Christ! The Pope is infallible when he acts as the supreme teacher of the infallible Church. Scripture witnesses to Jesus' founding a Church against which the Gates of Hell (heresy) cannot prevail. To this Church He gave a visible head and center of unity in the person of Peter and his successors, the Bishops of Rome. As visible head of the Church Militant, it is the Pope's duty to settle doctrinal disputes concerning truths contained in that "Deposit of Faith" committed by Christ to His Church.
This has been the role of the Pope since the beginning of Christianity, exercising his Supreme authority either as Chief Pastor of the Church in 'ex cathedra' dogmatic definitions or in acting in concert with his fellow-Bishops in Ecumenical Council; or in pronouncing a definitive judgment on a matter of faith or morals that has been constantly held by Pope and Bishops in the everyday teaching characterizing their ordinary and universal Magisterium. In each of these three modes of exercising his supreme authority as visible head of the Church, the Pope is infallible, and this is especially clear when he affirms he is "confirming his brethren" (the other bishops) in the Catholic Faith.
Infallibility does not mean merely freedom from actual error. It means more, namely freedom from the very liability to err in making dogmatic definitions or definitive doctrinal pronouncements. Thus, Papal 'ex cathedra' definitions (e.g., the Immaculate Conception and the Assumption) are infallible; and other definitive pronouncements by the Pope made to "confirm his brethren" (Luke 22:32) must similarly be regarded as infallible. It is a profound error to have attempted to confine the exercise of the Church's infallibility to the most solemnly worded Papal 'ex cathedra' definitions.
Vatican II teaches specifically:
"Loyal submission of the will and intellect must be given, in a special way, to the authentic teaching authority of the Roman Pontiff even when he does not speak ex Cathedra in such wise, indeed, that his supreme teaching authority be acknowledged with respect, and sincere assent be given to decisions made by him, conformably with his manifest mind and attention... The Roman Pontiff, head of the College of bishops, enjoys infallibility in virtue of his office, when, as supreme pastor and teacher of all the faithful who confirms his brethren in the faith (cf. Luke 22:32) he proclaims in an absolute decision a doctrine pertaining to faith and morals. For that reason his definitions are rightly said to be irreformable by their very nature and not by reason of the assents of the Church, in as much as they were made with the assistance of the Holy Spirit promised to him in the person of Blessed Peter himself; and as a consequence they are in no way in need of the approval of others, and do not admit of appeal to any other tribunal. For in such a case the Roman Pontiff does not utter a pronouncement as a private person, but rather does he expound and defend the teaching of the Catholic faith as the Supreme teacher of the Universal Church, in whom the Church's charism of Infallibility is present in a singular way."
(Dogmatic Constitution on the Church, n.25)
Even the declared enemies of the Catholic Church know what Pope Paul VI definitively taught about the sin of contraception (Humanae Vitae); they also know what Pope John Paul II has definitively taught concerning the sins of abortion and euthanasia (See Evangelium Vitae, ns. 57 and 65), and what he has definitively taught about women's ordination (Ordinatio Sacerdotalis).
It is the height of foolishness and/or stupidity for anyone professing to be Catholic to accuse the Catholic Church and its Chief Pastor of teaching falsely on these matters. And what absolute arrogance to believe that the dissenting views of a Charles Curran or Sr. Patricia Schoelles or Msgr. William Shannon or Fr. Bob Collins — are to be preferred to the infallible teaching of the Vicar of Christ on earth.