Editor’s note: this and related articles have now been published in a book entitled: Disputed Questions on Papal Infallibility (Os Justi Press, 2022).
On Particular Cases of Papal Teaching
The previous question (part 1 and part 2) considered the extension and limits of papal infallibility in general by means of a close examination of the criteria set forth at Vatican I respecting the subject, the object, and the act of infallible papal teaching. It remains in this question to consider whether the necessary criteria are fulfilled in particular cases of papal teaching. Although all Catholics agree in principle that the pope can teach infallibly in certain circumstances (as defined at Vatican I), there is much less agreement about how often and in what particular cases he has done so in practice. At one extreme, there are those who hold that the popes have only ever spoken infallibly twice, in defining the dogmas of the Immaculate Conception (1854) and Assumption (1950) of the Blessed Virgin Mary. At the other extreme, there are those who hold that everything the pope teaches in an official capacity in matters of faith or morals is at least practically infallible.
Regarding particular cases of papal teaching, there are twelve questions to be considered: (1) whether there have been more than two infallible papal definitions in the history of the Church; (2) whether the pope speaks infallibly in Dominus Iesus; (3) whether the pope speaks infallibly in Evangelium Vitae; (4) whether the pope speaks infallibly in Ordinatio Sacerdotalis; (5) whether the pope speaks infallibly in Veritatis Splendor; (6) whether the credo of Paul VI is an infallible profession of faith; (7) whether the pope speaks infallibly in Humanae Vitae; (8) whether the oath against Modernism is an infallible profession of faith; (9) whether the pope speaks infallibly in Quanta Cura; (10) whether the pope speaks infallibly in Providentissimus Deus; (11) whether the pope speaks infallibly in Exsurge Domine; (12) whether the pope speaks infallibly in Unam Sanctam.
Whether There Have Been
More Than Two Infallible Papal Definitions?
Objection 1. It seems that there have not been more than two infallible papal definitions in the history of the Church. For according to the common statement of the Lutheran-Roman Catholic Dialogue on teaching authority and infallibility in the Church: “There are only two papal pronouncements which are generally acknowledged by Catholics as having engaged papal infallibility: the dogma of the Immaculate Conception (1854) and that of the Assumption of the Blessed Virgin (1950).” But if any other papal pronouncement had engaged papal infallibility, this fact would be generally acknowledged by Catholics.
Objection 2. Furthermore, according to the Code of Canon Law: “No doctrine is understood to be defined infallibly unless this is manifestly evident.” But as the common statement of the Lutheran-Roman Catholic Dialogue notes, the infallible character of a papal pronouncement is not manifestly evident unless it claims infallibility for itself. And this does not occur outside the two definitions of Marian dogma mentioned above.
On the contrary, according to the official relatio on papal infallibility: “Thousands and thousands of dogmatic judgments have already gone forth from the Apostolic See.”
I answer that, it must be said that there have certainly been more than two infallible papal definitions in the history of the Church. The CDF gives six examples in its commentary on the concluding formula of the Profession of Faith: Benedictus Deus (1336) on the immortality of the spiritual soul and its immediate recompense after death; Ineffabilis Deus (1854) on the Immaculate Conception of Mary; Providentissimus Deus (1893) on the inspiration and inerrancy of Scripture; Apostolicae Curae (1896) on the invalidity of Anglican orders; Munificentissimus Deus (1950) on the Assumption of Mary; and Evangelium Vitae (1995) on the grave immorality of murder.
The Jesuit theologian Klaus Schatz, even though arbitrarily limiting his search to properly dogmatic definitions, recognizes seven instances of infallible papal teaching: the tome of Pope Leo the Great to Flavian of Constantinople (449); the dogmatic epistle of Pope Agatho to Emperor Constantine IV (680); Cum Occasione (1653), condemning five propositions of Cornelius Jansen as heretical; Auctorem Fidei (1794), which condemns eighty-five errors of the Synod of Pistoia, seven specifically as heretical; as well as the aforementioned definitions of Benedictus Deus (1336), Ineffabilis Deus (1854); and Munificentissimus Deus (1950).
The eminent ecclesiologist Louis Billot gives eleven examples: in addition to several of the aforementioned, he includes Unam Sanctam (1302) on the necessity for salvation of being subject to the Roman Pontiff; Exsurge Domine (1520), condemning the errors of Martin Luther; Caelestis Pastor (1687), condemning the errors of Miguel de Molinos; Cum Alias (1699), condemning the errors of François de Fénelon; Unigenitus Dei Filius (1713), condemning the errors of Pasquier Quesnel; and Quanta Cura (1864), condemning current errors.
Edmond Dublanchy gives a very similar list in the entry on papal infallibility in the monumental Dictionnaire de Théologie Catholique, although he hesitates over Quanta Cura. He also discusses, but ultimately leaves open, the possibility of including Pascendi Dominici Gregis (1907), on the doctrines of the modernists, and Lamentabili Sane (1907), condemning the errors of the modernists.
Salaverri provides a list drawn up from the historical investigations of Carlos da Silva Tarouca of twenty ex cathedra definitions from the first millennium alone.
Although none of these lists can claim to be definitive (nor exhaustive), to maintain that there have only been two instances of popes speaking infallibly can only be based on ignorance of history.
Reply to Objection 1. To the first it should be said that this statement represents only a common opinion of contemporary Catholics, which is not the same as the genuine consensus fidelium. This common opinion has been widely fostered and eagerly received by many who are eager to minimize the doctrine of papal infallibility in the hopes of easing ecumenical relations with those who reject the primacy of the pope. Although well intentioned, such an approach is misguided since true unity must be firmly rooted in truth.
Reply to Objection 2. To the second it should be said that even these two definitions of Marian dogma do not explicitly claim infallibility for themselves, and thus according to this criterion there would be no historical instances of popes speaking ex cathedra, which is absurd. What is required for the pope to speak ex cathedra is not that he claim or even intend to speak infallibly, but that he intend to speak definitively.
Whether the Pope Speaks Infallibly in Dominus Iesus?
Objection 1. It seems that the pope does not speak infallibly in the declaration Dominus Iesus (2000). For this declaration was issued by the CDF, and according to Salaverri, the CDF is not able to participate in the infallible exercise of the papal magisterium.
Objection 2. Furthermore, in order for Dominus Iesus to be infallible, the gift of infallibility would have to be communicated from the pope to the CDF. But the gift of infallibility is not able to be communicated, according to the words of Bishop Gasser: “How can infallibility be communicated? This I do not understand.”
Objection 3. Furthermore, according to Richard Gaillardetz: “While canon law envisions the participation of the Roman curia in papal governance of the Church, there is reason to question whether the curia can similarly participate in the doctrinal teaching authority of the pope. This authority cannot be delegated because it is his by virtue of his episcopal office as bishop of Rome.” Much less, therefore, can the infallible exercise of the papal magisterium be delegated to the CDF.
On the contrary, according to Bishop Angelo Amato, this declaration “was explicitly approved by the Supreme Pontiff with a formula of special authority. . . . It re-proposes truths of divine Catholic faith and doctrinal truths to be firmly followed. Hence, the assent requested of the faithful is definitive and irrevocable.” But definitive and irrevocable assent are required only in response to infallible teaching.
I answer that, it must be said that, in the declaration Dominus Iesus, the necessary conditions pertaining to the object and act of infallibility are clearly fulfilled, for various doctrines pertaining to faith are proposed explicitly as to be firmly believed or held. The only question, therefore, concerns the condition pertaining to the subject of papal infallibility, since this document was promulgated by the CDF and not directly by the pope himself; and although the CDF is able to participate in the ordinary (authentic) magisterium of the pope, it is generally held that the CDF is not able to participate in the infallible papal magisterium.
However, the documents of the CDF can be approved by the pope either in a common form (in forma communi) or in a specific form (in forma specifica). When such a document is approved in the common form, it remains a document of the CDF; but if it is approved in the specific form, then it becomes a properly pontifical act. Hence, there is nothing to prevent the pope from defining doctrine infallibly in a document of the CDF that he approves in the specific form. And this accords with the words of Pope Pius IX, where he says that dogmas of divine faith can be “defined by the explicit decrees of ecumenical councils or of Roman pontiffs and of this Apostolic See.” For what would be the purpose of mentioning the decrees of the Apostolic See in addition to those of the Roman pontiffs, unless he speaks of the doctrinal decrees of the Roman Congregations?
Now the declaration Dominus Iesus was approved by the pope in the specific form, as Matthew Dunn shows. Traditionally, approval in the specific form has been indicated by phrases such as motu proprio, or plenitudine suae potestatis, or especially ex certa scientia. Now the formula of approval appended to Dominus Iesus is as follows: “The supreme pontiff John Paul II, in an audience granted to the undersigned Cardinal Prefect of the Congregation for the Doctrine of the Faith, on June 16, 2000, with certain knowledge (certa scientia) and by his apostolic authority (et auctoritate sua apostolica), ratified (ratam) and confirmed (confirmavit) this declaration, adopted in plenary session, and ordered its publication.” By contrast, a typical formula of approval in the common form is as follows: “The sovereign pontiff, at the audience granted to the undersigned Cardinal Prefect, approved the present document, adopted in ordinary session of this congregation, and ordered its publication.”
It may be objected that the formula of approval appended to Dominus Iesus does not use the precise phrase “in forma specifica approbavit,” which it ought to do, according to the General Regulations of the Roman Curia promulgated in 1992. However, as advisable as it may be for the pope to observe such a rule in order that his intentions may be more clearly manifest, this rule cannot prevent the pope from using other traditional formulae to indicate his intention to approve a document in the specific form. That it was the pope’s intention to approve this document in the specific form can also be confirmed by his words in an Angelus address given later in the same year, where he says: “With the Declaration Dominus Iesus—Jesus is Lord—approved by me in a special way (approvata da me in forma speciale) at the height of the Jubilee Year. . .” The Italian phrase ‘in forma speciale’ corresponds closely to the traditional Latin phrase ‘in forma specifica’. Moreover, according to Tarcisio Bertone, then the Secretary of the CDF, the formula of approval appended to Dominus Iesus is no ordinary approval but indicates “special and elevated authority.” But there is no formula of special or elevated authority other than the approval in the specific form.
Therefore, since the declaration Dominus Iesus, in virtue of its approval in the specific form, must be regarded as a formal act of the pope as supreme head of the Church, and since it proposes matters of faith in a definitive way, it must be admitted that the following propositions are infallibly defined:
- It must be firmly believed that, in the mystery of Jesus Christ, the incarnate Son of God, who is ‘the way, the truth, and the life’ (Jn 14:6), the full revelation of divine truth is given.
- The distinction between theological faith and belief in the other religions must be firmly held.
- The doctrine of faith must be firmly believed which proclaims that Jesus of Nazareth, son of Mary, and he alone, is the Son and the Word of the Father.
- The doctrine of faith regarding the unicity of the salvific economy willed by the one and triune God must be firmly believed, at the source and center of which is the mystery of the incarnation of the Word, mediator of divine grace on the level of creation and redemption (cf. Col 1:15–20), he who recapitulates all things (cf. Eph 1:10), he “whom God has made our wisdom, our righteousness, and sanctification and redemption” (1 Cor 1:30).
- The truth of Jesus Christ, Son of God, Lord and only Savior, who through the event of his Incarnation, death and resurrection has brought the history of salvation to fulfilment, and which has in him its fullness and center, must be firmly believed as a constant element of the Church’s faith.
- It must therefore be firmly believed as a truth of Catholic faith that the universal salvific will of the one and triune God is offered and accomplished once for all in the mystery of the Incarnation, death, and resurrection of the Son of God.
- Therefore, in connection with the unicity and universality of the salvific mediation of Jesus Christ, the unicity of the Church founded by him must be firmly believed as a truth of Catholic faith. Just as there is one Christ, so there exists a single body of Christ, a single bride of Christ: “a single Catholic and apostolic Church.”
- The Catholic faithful are required to profess that there is an historical continuity—rooted in the apostolic succession—between the Church founded by Christ and the Catholic Church.
- It must be firmly believed that “the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and baptism (cf. Mk 16:16; Jn 3:5), and thereby affirmed at the same time the necessity of the Church which men enter through baptism as through a door.”
Reply to Objection 1. To the first it must be said that Salaverri offers no argument in defense of this assertion, saying merely “we may suppose” that even documents approved in the specific form “have not been approved infallibly, but with a grade of authority that is lower than a definition ex cathedra.” Such a supposition, however, seems incompatible with what he himself also says—namely, that when the pope approves documents in the specific form, he “makes these decrees his own and they must be accepted as his formal decrees.” For certainly the pope is able to speak infallibly in his own formal decrees.
Reply to Objection 2. To the second it must be said that these words of Bishop Gasser are taken out of context. What he rejects here is the idea, put forward by some, that the sole subject of infallibility in the Church is the pope, who then communicates the gift of infallibility to the Church. But this does not exclude that the pope could exercise his infallibility through the CDF by approval of a document in the specific form.
Reply to Objection 3. To the third it must be said that the pope does not delegate his teaching authority to the CDF in such a way that the latter would be able to exercise this authority independently. Rather, he allows the CDF a participation in his own teaching authority through his specific approval of individual acts.
Whether the Pope Speaks Infallibly in Evangelium Vitae?
Objection 1. It would seem that the pope does not speak infallibly in Evangelium Vitae (1995). For Cardinal Ratzinger is reported to have said: “Pope John Paul II considered making an infallible declaration against abortion and euthanasia in his latest encyclical Evangelium Vitae, but the idea was dropped because the teachings were considered ‘so evident’ in Christian faith and tradition.” But if the pope did not intend to speak infallibly in Evangelium Vitae, then he did not speak infallibly.
Objection 2. Furthermore, according to Bishop Anthony Bosco: “If the pope wanted to say something was infallible, he would have used the word.”
Objection 3. Furthermore, in order to speak infallibly, the pope must propose a doctrine of faith or morals as definitively to be held, as shown above. But this phrase is not used in the encyclical.
Objection 4. Furthermore, encyclical letters are organs of the ordinary papal magisterium, which is not infallible, as shown above. But Evangelium Vitae is an encyclical letter.
On the contrary, according to the Vatican summary of Evangelium Vitae, the encyclical contains “doctrinal affirmations of very high magisterial authority, presented with particular solemnity by the supreme pontiff,” which seems to indicate an exercise of the solemn (extraordinary) magisterium, which is infallible.
I answer that, it must be said that the three essential conditions for speaking infallibly are fulfilled in Evangelium Vitae. In the first place, there can be no doubt that the pope speaks in his official capacity as head of the universal Church, for the encyclical letter is explicitly addressed to all bishops, priests and deacons, men and women religious, lay faithful, and all people of good will.
Secondly, when the pope declares and confirms the grave immorality of murder, abortion, and euthanasia, it is clear that his teaching regards matters of faith or morals. As Francis Sullivan says: “In order to be capable of being taught with infallibility, a moral doctrine must be either formally revealed, or so intimately connected with revealed truth as to be required for its defense or exposition. It would seem to me that the teaching of the encyclical on the immorality of murder, abortion, and euthanasia meets that requirement.”
Thirdly, it is required that the pope not merely teach but define doctrine. Now this word “define,” according to the official relatio on papal infallibility, “signifies that the pope directly and conclusively pronounces his judgment about a doctrine which concerns matters of faith and morals in such a way that each one of the faithful is able to be immediately certain . . . of the mind of the Roman pontiff; in such a way, indeed, that one may know for certain that this or that doctrine is held to be heretical, proximate to heresy, certain or erroneous, etc., by the Roman pontiff.” And there are in Evangelium Vitae three places in which the pope directly and conclusively pronounces his sentence about doctrines that concern morals in such a way that there can be no doubt that, according to the mind of the Roman pontiff, these doctrines are to be held definitively by the whole Church.
First, on the grave immorality of murder:
Therefore, by the authority which Christ conferred upon Peter and his successors, and in communion with the bishops of the Catholic Church, I confirm that the direct and voluntary killing of an innocent human being is always gravely immoral. This doctrine, based upon that unwritten law which man, in the light of reason, finds in his own heart (cf. Rom 2:14–15), is reaffirmed by Sacred Scripture, transmitted by the Tradition of the Church and taught by the ordinary and universal magisterium.
Now when the pope explicitly states that this doctrine is affirmed by Sacred Scripture, he proposes it as being contained in divine revelation; and when he states that it is transmitted by the Tradition of the Church and taught by the ordinary and universal magisterium, he makes it clear that it is to be firmly believed as such. Hence, the doctrine is proposed as one that is to be firmly believed as divinely revealed. It must, therefore, be admitted that this is an infallible definition of a dogma of divine and Catholic faith (de fide credenda).
Secondly, on the grave immorality of abortion:
Therefore, by the authority which Christ conferred upon Peter and his successors, in communion with the bishops—who on various occasions have condemned abortion and who in the aforementioned consultation, albeit dispersed throughout the world, have shown unanimous agreement concerning this doctrine—I declare that direct abortion, that is, abortion willed as an end or as a means, always constitutes a grave moral disorder, since it is the deliberate killing of an innocent human being. This doctrine is based upon the natural law and upon the written Word of God, is transmitted by the Church’s Tradition and taught by the ordinary and universal magisterium.
In this case, the pope states that this doctrine is based upon (rather than affirmed by) the written Word of God, thus proposing it as being at least closely connected to divine revelation; and when he states that it is transmitted by the Church’s Tradition and taught by the ordinary and universal magisterium, he makes it clear that it is to be definitively held as such. Hence, it must be admitted that this is an infallible definition of a truth of Catholic doctrine (de fide tenenda).
Thirdly, on the grave immorality of euthanasia:
Taking into account these distinctions, in harmony with the magisterium of my predecessors and in communion with the bishops of the Catholic Church, I confirm that euthanasia is a grave violation of the law of God, since it is the deliberate and morally unacceptable killing of a human person. This doctrine is based upon the natural law and upon the written Word of God, is transmitted by the Church’s Tradition and taught by the ordinary and universal magisterium.
Here again, when the pope states that this doctrine is based upon the written Word of God, he proposes it as being at least closely connected to divine revelation; and when he states that it is transmitted by the Church’s Tradition and taught by the ordinary and universal magisterium, he makes it clear that it is to be definitively held as such. Here too, therefore, we have an infallible definition of a truth of Catholic doctrine (de fide tenenda).
Reply to Objection 1. To the first it must be said that “it is a bit risky to draw firm conclusions from a partial report of what was said at a press conference,” as Sullivan notes. But in any case, whether or not the pope consciously intends to speak infallibly cannot be decisive, for many popes spoke infallibly long before the doctrine of papal infallibility was clearly taught or defined. Therefore, a pope could exercise the charism of infallibility without himself fully understanding that he does so. What is decisive is that the pope intends to speak conclusively, or definitively; and this intention is manifest in Evangelium Vitae with respect to the grave immorality of murder, abortion, and euthanasia (see above, Question 1, article 1; Question 1, article 5, reply to objection 1).
Reply to Objection 2. To the second it must be said that “even in their solemn dogmatic definitions,” as Sullivan notes, “popes have not explicitly said that they were speaking infallibly. One has to judge, on other grounds, whether the conditions laid down by Vatican I for ex cathedra statements were fulfilled.”
Reply to Objection 3. To the third it must be said that, according to the official relatio on papal infallibility, it is not required for the popes to use any particular phrase or formula in their ex cathedra definitions. And as Sullivan says: “The formula which he used in this encyclical in condemning murder, abortion, and euthanasia, would seem sufficient to remove any doubt as to whether he was expressing a judgment which he, along with the bishops, wanted all Catholics to hold definitively. It is hard to see how any other interpretation would do justice to the language which he used.”
Reply to Objection 4. To the fourth it must be said that, although encyclical letters are typically used as instruments of the ordinary (authentic) papal magisterium, there is nothing to prevent the pope from using an encyclical letter to promulgate a solemn definition, as Fenton shows.
To be continued next week.
 Lutheran-Roman Catholic Dialogue [henceforth: LRCD], “Teaching Authority and Infallibility in the Church: Common Statement,” Theological Studies 40 (1979): 148.
 1983 CIC, can. 749, §3.
 See LRCD, “Teaching Authority,” 149.
 Mansi, 52:1215 A.
 See CDF, Doctrinal Commentary, §11.
 See Klaus Schatz, “Welche bisherigen päpstlichen Lehrentscheidungen sind ‘ex cathedra’? Historische und theologische Überlegungen,” in Dogmengeschichte und katholische Theologie, ed. Werner Löser, Karl Lehmann, and Matthias Lutz-Bachmann (Würzburg: Echter, 1985), 402–22; see also Sullivan, Creative Fidelity, 82–89.
 See Billot, Tractatus de Ecclesia Christi, 642–44.
 See Dublanchy, “Infaillibilité,” 7:1703–4.
 See Carlos da Silva Tarouca, Institutiones historiae ecclesiasticae: Ecclesia in imperio Romano-Byzantino (Rome: Gregorian University, 1933), 86–190; see also Salaverri, Tractatus de Ecclesia Christi, nos. 623–29.
 See Salaverri, Tractatus de Ecclesia Christi, no. 665; see also Sullivan, Creative Fidelity, 19–20.
 Mansi, 52:1216 C.
 Gaillardetz, Teaching with Authority, 287.
 Cited by Matthew W. I. Dunn, “The CDF’s Declaration Dominus Iesus and Pope John Paul II,” Louvain Studies 36 (2012): 66, with reference to Angelo Amato, “The Dominus Iesus and the Other Religions,” Pro Dialogo: Pontificium Consilium pro Dialogo inter Religiones 126 (2007): 234.
 See CDF, Donum Veritatis, §18.
 See Dulles, Magisterium, 53; see also John M. Huels, “Interpreting an Instruction Approved In Forma Specifica,” Studia Canonica 32 (March 1998): 5–46.
 Pius IX, Tuas Libenter.
 See Dunn, “The CDF’s Declaration Dominus Iesus,” 46–75.
 Dunn, “The CDF’s Declaration Dominus Iesus,” 65; see also: New Commentary on the Code of Canon Law, ed. John P. Beal et al. (New York: Paulist Press, 2000), 58; Valentín Gómez-Iglesias, “Naturaleza y origen de la confirmación ex certa scientia,” Ius Canonicum 25 (1985): 91–116.
 Acta Apostolicae Sedis, vol. 92 (2000): 765.
 See, for example, the approval appended to the CDF Instruction Ardens Felicitatis (2000), issued in the same year as Dominus Iesus.
 See Secretariat of State, Regolamento Generale della Curia Romana (1992), a. 110, sec. 4.
 Pope John Paul II, Angelus Address (Oct. 1, 2000).
 Cited by Dunn, “The CDF’s Declaration Dominus Iesus,” 66, with reference to Bertone’s address to the Press at the presentation of Dominus Iesus.
 CDF, Dominus Iesus, §5.
 Ibid., §7.
 Ibid., §10.
 Ibid., §11.
 Ibid., §13.
 Ibid., §14.
 Ibid., §16.
 Ibid., §17.
 Ibid., §20.
 Salaverri, Tractatus de Ecclesia Christi, no. 665 (trans. Baker, Sacrae Theologiae Summa, vol. 1B, 244).
 See Mansi, 52:1216 C.
 Cited by Francis A. Sullivan, “The Doctrinal Weight of Evangelium vitae,” Theological Studies 56 (1995): 562, with reference to “On File,” Origins 24/43 (April 13, 1995), 734.
 Cited by Sullivan, “Doctrinal Weight,” 563, with reference to the Pittsburgh Post-Gazette (Mar. 30, 1995), A-5.
 Cited by Sullivan, “Doctrinal Weight,” 561, with reference to “The Vatican’s Summary of Evangelium vitae,” Origins 24/42 (Apr. 6, 1995), 728.
 Sullivan, “Doctrinal Weight,” 564.
 Mansi, 52:1316 AB.
 John Paul II, Encyclical Letter Evangelium Vitae (1995), §57.
 John Paul II, Evangelium Vitae, §62.
 John Paul II, Evangelium Vitae, §65.
 Sullivan, “Doctrinal Weight,” 562.
 Sullivan, “Doctrinal Weight,” 563.
 See Mansi, 52:1215 A.
 Sullivan, “Doctrinal Weight,” 563.
 Joseph C. Fenton, “The Doctrinal Authority of Papal Encyclicals,” American Ecclesiastical Review 121 (1949): 136–50, 210–20; “Infallibility,” 177–98.
Dr. John Joy teaches Theology at St. Ambrose Academy in Madison, Wisconsin. In his spare time he also serves as President of the St. Albert the Great Center for Scholastic Studies and Managing Editor for the Aquinas Institute. His primary academic interests are in the theology and philosophy of St. Thomas Aquinas, dogmatic theology, and especially questions of infallibility and the magisterium of the Church. He is the author of On the Ordinary and Extraordinary Magisterium from Joseph Kleutgen to the Second Vatican Council (Muenster: Aschendorff, 2017) as well as various articles published in Nova et Vetera, Seminary Journal, New Blackfriars, and Antiphon.