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50th Anniversary of Paul VI’s Encyclical Mysterium Fidei

September 3, 1965. Fifty years ago today, right before the last session of the Second Vatican Council, Pope Paul VI promulgated his dogmatically rich encyclical on the mystery of the Holy Eucharist, Mysterium Fidei, unambiguously reaffirming the doctrine of the Council of Trent on transubstantiation and condemning the fashionable errors of the day such as “transfinalization” and “transsignification.”

Reading those words brings back memories of my high school youth group in the 1980s, when a dear priest, who (I am convinced) was really trying to do his best but had had a poor theological training, handed me a recently published book on the Eucharist that, even at the time, struck me as odd. It was only later on, reading Ludwig Ott and Paul VI, that I realized this book was saturated with all those fashionable errors that Rome had already condemned as inimical to and incompatible with the Faith. Ah, how effective is Church authority in the modern age! But I digress.

Here is a brief excerpt in which Paul VI, wishing to support the appropriateness and immutability of the dogmatic language of “transsubstantiation,” explains why precision and fixity in theological language is absolutely required by the Christian faith, suited to the defense of the truth and to the needs of man. Here is a refreshing moment of Montini the anti-Modernist—while under his very nose worked the "mealy-mouthed scoundrel" who was already setting in motion the ultimate method for relativizing and marginalizing the beautiful Eucharistic doctrine that Paul VI was setting forth.

9. It is logical, then, that we should follow as a guiding star in our investigations of this mystery the magisterium of the Church, to which the divine Redeemer entrusted for protection and for explanation the revelation which He has communicated to us through Scripture or tradition. For we are convinced that “what since the days of antiquity was preached and believed throughout the whole Church with true Catholic faith is true, even if it is not submitted to rational investigation, even if it is not explained by means of words” (St. Augustine, Contr. Julian. VI. 5, 11, PL 44, 829).

10. But this is not enough. Once the integrity of the faith has been safeguarded, then it is time to guard the proper way of expressing it, lest our careless use of words give rise, God forbid, to false opinions regarding faith in the most sublime things. St. Augustine gives a stern warning about this when he takes up the matter of the different ways of speaking that are employed by the philosophers on the one hand and that ought to be used by Christians on the other. “The philosophers,” he says, “use words freely, and they have no fear of offending religious listeners in dealing with subjects that are difficult to understand. But we have to speak in accordance with a fixed rule, so that a lack of restraint in speech on our part may not give rise to some irreverent opinion about the things represented by the words” (De Civit. Dei X, 23, PL 41, 300).

11. And so the rule of language which the Church has established through the long labor of centuries, with the help of the Holy Spirit, and which she has confirmed with the authority of the Councils, and which has more than once been the watchword and banner of orthodox faith, is to be religiously preserved, and no one may presume to change it at his own pleasure or under the pretext of new knowledge. Who would ever tolerate that the dogmatic formulas used by the ecumenical councils for the mysteries of the Holy Trinity and the Incarnation be judged as no longer appropriate for men of our times, and let others be rashly substituted for them? In the same way, it cannot be tolerated that any individual should on his own authority take something away from the formulas which were used by the Council of Trent to propose the Eucharistic Mystery for our belief. For these formulas—like the others that the Church used to propose the dogmas of faith—express concepts that are not tied to a certain specific form of human culture, or to a certain level of scientific progress, or to one or another theological school. Instead they set forth what the human mind grasps of reality through necessary and universal experience and what it expresses in apt and exact words, whether it be in ordinary or more refined language. For this reason, these formulas are adapted to all men of all times and all places.

12. They can, it is true, be made clearer and more obvious; and doing this is of great benefit. But it must always be done in such a way that they retain the meaning in which they have been used, so that with the advance of an understanding of the faith, the truth of faith will remain unchanged. For it is the teaching of the First Vatican Council that “the meaning that Holy Mother the Church has once declared, is to be retained forever, and no pretext of deeper understanding ever justifies any deviation from that meaning” (Constit. Dogm. De Fide Cathol. c.4).