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Dueling Ultimate Authorities

When two 'supreme sources' clash, here's how the Church defends its claim to the truth.

There is a certain claim you will hear among many Protestant apologists that goes like this: all appeals to an ultimate authority are necessarily circular, and thus defenses of the doctrines of sola scriptura or perspicuity (AKA clarity) can be made solely by citing Bible verses, since, so goes the argument, the Bible is in this case the ultimate authority. For example, we read in Wayne Grudem’s Systematic Theology, “For all arguments for an absolute authority must ultimately appeal to that authority for proof: otherwise the authority would not be an absolute or highest authority.” Or, as Calvinist apologist Cornelius Van Til acknowledged, “[the] position we have sought to outline is frankly taken from the Bible. . . . From the non-Christian point of view our position with respect to God and Scripture is the product of ‘circular reasoning.’”

If this claim is correct, it would mean that the logical fallacy of question-begging—in which an argument is made that presumes precisely what is in question—is permitted when one makes an appeal to an ultimate authority. This, however, presents the immediate problem of how to evaluate two (or more) competing arguments from different supposed ultimate authorities. You cite the Bible; I’ll counter with the Quran. You cite the Quran; I’ll counter with the Book of Mormon. And so on. How does one adjudicate these appeals to ultimate authority, if the claimant is permitted to simply cite from his own sacred text as proof of its ultimate authority?

The answer is that you cannot, unless you are willing to admit you have no means of adjudicating between competing appeals to the ultimate authority that are based solely on the grounds that those competing authorities claim to be the ultimate authority. But if you have no means of evaluating those competing claims, then there would be no rational means of identifying which one is the real ultimate authority, since we have dispensed with logic. In such a scenario, the operative force propelling the claim thus becomes the will (simply asserting this to be the ultimate authority) or the emotions (simply feeling that this is the ultimate authority).

When I’ve pointed this out to Protestants, a common retort is “But Catholics do the same thing.” Protestants, they’ll say, cite the Bible as the reason the Bible is their ultimate authority, whereas Catholics cite the magisterial authority of the Church as the reason the Church is their ultimate authority. But is that accurate? The answer is no. The reason why is what are called the motives of credibility, which deserve a much broader appreciation among Catholics, especially those seeking to engage in fruitful ecumenical dialogue with their Protestant brothers and sisters.

The motives of credibility are found in the Catechism of the Catholic Church:

What moves us to believe is not the fact that revealed truths appear as true and intelligible in the light of our natural reason: we believe “because of the authority of God himself who reveals them, who can neither deceive nor be deceived.” So “that the submission of our faith might nevertheless be in accordance with reason, God willed that external proofs of his Revelation should be joined to the internal helps of the Holy Spirit.” Thus the miracles of Christ and the saints, prophecies, the Church’s growth and holiness, and her fruitfulness and stability “are the most certain signs of divine Revelation, adapted to the intelligence of all”; they are “motives of credibility” (motiva credibilitatis), which show that the assent of faith is “by no means a blind impulse of the mind” (156).

Let me unpack the above. The Church acknowledges that our acceptance of revealed truth—also known as revelation—requires an act of faith. Thus, for example, our belief in the Incarnation or the Trinity, both of which are revealed truths, requires faith, because they are not things that can be known by reason alone. You can’t reason your way to a human person in first-century Palestine possessing a divine nature, or one God who is also three persons.

Nevertheless, there are what the Catechism calls “external proofs” of revelatory information, accessible to our natural reason, that can be evaluated solely on rational grounds. In other words, there are reasonable, internally coherent data presented to our intellects that can confirm revelation and give us confidence that revelation is indeed true. They are, says Catholic theologian Lawrence Feingold in Faith Comes from What Is Heard, “supernatural signs that manifest the miraculous action of God,” whose purpose “is to show that an alleged revelation from God is truly his word.” And, as the Catechism says, this information is “adapted to the intelligence of all,” meaning anyone can evaluate it solely on rational grounds.

Motives of credibility demonstrate that an act of faith is “reasonable and morally compelling,” explains Feingold. “With sufficient motives of credibility, it would be unreasonable not to believe; without such motives, it would be unreasonable to believe. Belief in an alleged revelation that is not supported by sufficient reasons to think that God is its source would put one in danger of attributing mere human words and claims to God.” Thus, it is the motives of credibility that bridge the gap between natural human reason and true, authentic faith.

The motives of credibility are not a new idea in Catholic thought. Medieval theologian St. Thomas Aquinas in his Summa Contra Gentiles writes,

Divine wisdom himself, who knows all things most fully, deigned to reveal to man the secrets of God’s wisdom (Job 11:6), and by suitable arguments proves his presence, and the truth of his doctrine and inspiration, by performing works surpassing the capability of the whole of nature, namely, the wondrous healing of the sick, the raising of the dead to life, a marvelous control over the heavenly bodies, and, what excites yet more wonder, the inspiration of human minds, so that unlettered and simple persons are filled with the Holy Spirit, and in one instant are endowed with the most sublime wisdom and eloquence (I a. 6).

Aquinas calls the motives of credibility “suitable arguments” to prove revelation and cites some of the same examples referenced by the Catechism, such as miracles, a proof that is found not only in the Bible, but across Church history, from the time of the early church fathers to the present day.

The Catholic Church does not claim to be the ultimate authority on divine revelation simply because it says so. Rather, the Church appeals to rational, extra-magisterial reasons, or motives of credibility, accessible to all people, such as miracles, to support that claim.

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