Lesson 4b: The Church's Infallible Moral Teaching

Since, as was shown in the last lesson, Church doctrine develops without ceasing to be true to Jesus' original unchangeable teaching, it should be clear why at any given period of history there are different levels of certitude in the teaching of pope and bishops (Magisterium). (1) Some teachings form the ordinary teaching of the whole college of bishops headed by the Pope as revealed to faith, for example that the Jews are God's Chosen People. All Catholics must believe these revealed truths on divine faith as infallibly true and essentially unchangeable. (Note that it is not sufficient just that they be universally taught but it is required they be taught to be revealed by God). (2) Sometimes controversies arise over these ordinary teachings (such as the Arian heresy) or the Magisterium thinks it inspiring to emphasize some particular truth (such as Mary's Immaculate Conception and Assumption). Then either an ecumenical council of the bishops with the pope's consent or the pope on his own authority may declare that this is a revealed truth by a solemn or extraordinary definition. The infallibility of such extraordinary teaching is thus made evident to all Catholics even if they would not have been sure that as ordinary teaching of the Magisterium it had the universality and basis in revelation that would make it evidently infallible.

Besides these two levels of infallible teaching that must be received on divine faith, there is also teaching that is not itself divinely revealed, yet if it were false would either result in the contradiction of some infallible teaching, or would make the Church unable to define its teachings as credible. For example, although the Bible does not speak of modern science, to hold that modern science has proved that miracles are impossible contradicts the revealed truth that Jesus worked miracles. It also makes it impossible for the Church to defend the credibility of the faith by the "moral miracle" of the Church. When the Church corrects such assertions this teaching is also infallible because otherwise none of the Church's teaching could be infallible, since all could be contradicted. However, since these corrections as such are not revealed, they do not require the assent of divine faith, but only the obedience of mind and will to the Church guidance.

Other teachings of the Church are not known to be infallible and might someday require some correction or re-formulation. This does not mean, however, that Catholics are free to deny them if in fact the development of doctrine at a given stage of history has made it very probable or even certain that they are revealed or are closely connected to such revealed truths. Thus before the Council of Chalcedon infallibly defined that Jesus is a Divine Person with a divine and human nature, it was clear to most Christians that this was a revealed truth by which they lived and for which they were willing to die. On the other hand, there can be teachings of the Magisterium for which there has not yet been sufficient doctrinal development to be sure that they could not be changed in the future. An example might be John Paul II's teaching on capital punishment as contrary to human dignity. Yet, again this does not mean that a Catholic may simply reject such teachings. In fact all Magisterial teachings must be received with an obedience of mind and will, not because we are sure they are revealed and therefore infallible, but out of obedience to the Magisterium as our surest guide on the Way of Life. Magisterial teachings always have greater authority than any human opinion, even that of the most distinguished theologians. I pointed out in the last lesson that in non-infallible teachings there is a possibility, though a generally remote one, of error, and that a theologian who is certain should point this out in a way that does not cause scandal. This is why John Paul II can now admit that a Pope made a mistake in the Galileo case, or that previous warnings against certain historical views of biblical scholars or Darwinian evolution are to be corrected. These mistakes did not pertain to infallible teachings of levels (1) and (2) above, but resulted from an incomplete development of doctrine and the acceptance by popes of too hasty opinions of theologians. Though they did serious harm, this in time has been corrected. In the meantime they were a safer guide for the conscience of Catholics than were the half-truths of science that even when correct had to be received with caution because it was not yet clear they were really true. As the government controls experimental drugs before they have been thoroughly tested, so the Church must proceed with caution to protect its Sacred Tradition.

In the development of doctrine the whole Church plays a necessary part. The Bible and Sacred Tradition are handed down not only through the pope and bishops but through the whole faithful, especially parents in instructing their children in the Faith. Moreover, ordinary Christians, as well as learned theologians, and saints with mystical gifts, and the events of history that put truth to the test, all play a part in the development of doctrine. Yet as this positive development takes place there must be an authority that by the aid of the Holy Spirit can discern, judge, and declare what is authentic and what is not, separating the wheat from the chaff. It must do this with increasing certitude and finally with authority or the Church itself could not be infallible as Jesus promised it would be, saying, "Teach all nations . . . I am with you until the end of the ages" (Mt 28:16-20). History shows that in fact the teaching of the Catholic Church has been consistently the same for two thousand years, while in the Christian churches that have separated from her there has been division after division and no clear and consistent understanding of what Jesus taught.

Note that in development of moral doctrine the changes have usually not been the direction of relaxing moral principles or norms to accommodate a desire for "freedom" in the sense of doing what one pleases. That kind of relaxation in society means a lowering of moral standards and an increase of selfish autonomy and leads to social irresponsibility. Instead development is usually in the direction of (a) applying Gospel norms more consistently; (b) applying Gospel norms more precisely in view of the actual facts. Jesus criticized the Pharisees for "straining at a gnat and swallowing a camel," i.e. lacking a sense of priorities which is a kind of inconsistency. He also rebuked them for forgetting that "the Sabbath is made for man, not man for the Sabbath," i. e., forgetting the purpose of a law and hence applying it wrongly. Good moral theology seeks to help the Church refine its moral teachings by seeking consistency and precision. It does not attempt to change its revealed principles, nor does it neglect the tradition of their application.


  1. John Paul II, The Splendor of Truth (Veritatis Splendor), 1993

  2. John Paul II, The Gospel of Life (Evangelium Vitae), 1995


  1. Why is the moral teaching of the Magisterium a safer guide for conscience than the views of theologians or our own opinions in moral matters?

  2. Why has the Magisterium not infallibly defined all the moral norms?

  3. What is the role of the Holy Spirit in aiding the individual apply the moral teaching of the church to their own problems?

  4. What arguments could be used for and against the infallibility of the teaching of Humanae Vitae on marriage?

  5. How can we be sure what Jesus taught about sexual behavior?


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