The Catholic Church recognizes a hierarchy of truths, six levels of theological certainty. Although only the highest three levels are infallible teaching, we are to submit with humble fidelity also to the fourth level, certain doctrine. Holy Mother Church explains in Lumen Gentium § 25:
“This religious submission of mind and will must be shown in a special way to the authentic magisterium of the Roman Pontiff, even when he is not speaking ex cathedra; that is, it must be shown in such a way that his supreme magisterium is acknowledged with reverence, the judgments made by him are sincerely adhered to, according to his manifest mind and will. His mind and will in the matter may be known either from the character of the documents, from his frequent repetition of the same doctrine, or from his manner of speaking.”
Let us look at these six levels, using as examples the Catholic teaching on angels, taking our information from Father John A. Hardon, S.J., Catholic Catechism on the Angels (Bardstown, KY: Eternal Life, 2000) pp. 11-13.
Dogma is the highest level of Catholic theological certainty. It is a doctrine that has been expressly revealed by God through Sacred Scripture or Sacred Tradition and formally defined by a true pope, either acting alone or in union with an ecumenical council. The solemn definition, called an exercise of the extraordinary Magisterium, is taught ex cathedra, “from the chair,” because the pope is exercising his authority “from the chair of Peter.” All dogmas are doctrines, because they have been the constant teaching of the Church for two thousand years in every place and at every time. It is a dogma of the Catholic faith that angels and demons exist. “The Son of man will send his angels” Mt 13:41. “I saw Satan fall like lightning from heaven” Lk 10:18.
Dogmatic doctrine, the second level, has been expressly revealed by God in Sacred Scripture or Sacred Tradition. It is not solemnly defined by a pope, but formed by the constant teaching of the Church for two thousand years in every place and at every time. Because there is no solemn definition, Catholic teaching of dogmatic doctrine is called an exercise of the ordinary Magisterium. It is dogmatic doctrine that God assigns a guardian angel to each baptized Christian. “Behold, I send an angel before you, to guard you on the way and to bring you to the place which I have prepared” Ex 23:20. “For he will give his angels charge of you to guard you in all your ways” Ps 91:11. “Their angels always behold the face of my Father who is in heaven” Mt 18:10.
Infallible doctrine, the third level, is not dogma because it has been only implicitly revealed by God, but is doctrine because it has been the constant teaching of the Church for two thousand years in every place and at every time. These first three levels are infallible, therefore irreversible. It is infallible doctrine that we are able to invoke the aid of holy angels for our guidance and protection.
Certain doctrine, the fourth level, must be believed by the faithful, but is reversible. It is certain doctrine that God assigns a guardian angel to every human person in the first instant of conception. Dr. William May tells us: “Note that the proper way to speak of teachings proposed in this way is to say that they are authoritatively taught; it is not proper to say that they are fallibly taught.”
Probable doctrine, the fifth level, is ordinarily accepted by the Catholic intellect and will, but is less than certain and so a Catholic may question it without incurring sin. It is probable doctrine that all the angels, both saved and lost, were originally created in the state of sanctifying grace.
Permissible belief, the sixth level, is speculative for the mind to believe and permissible for the will to practice because it does not contradict higher levels of Catholic teaching. It is permissible belief that not only individuals but also parishes, dioceses, religious institutes, cities, states, and even nations have their own guardian angels.
We can understand how a doctrine can be certain but reversible by imagining a mother telling her small child that he may cross the street only while holding her hand. It is certain that this is necessary to the small child’s safety. However, twenty years later, the same mother does not ask her son to hold her hand while they cross the street, because he is now able to cross safely on his own. Certain doctrine is always authoritative for the day on which it is taught.