Postscriptum to Reflections on the Ubi v. Ybarra Debate
Putting the "auctoritas" objection to rest
Author’s note: I have an important follow-up to this essay, in which I respond to some critical remarks. I encourage you to read it when finished. You may find it at my personal Substack here: Auctoritas et Potestas Iterum: Ubi Petrus Tweets Back.
I’d like to address one more skeptical objection that Denny raised in the debate. It’s only sightly more sophisticated than the sophistical objections concerning “always” and suggestione that I analyzed in Part 1.
This objection targets Pope St. Leo the Great’s Tome. We’ll begin with a quotation from an older article of Denny’s, which formed the basis of his comment during the debate:
The term St. Leo uses in the Latin original here is “auctoritas” and though it does mean ‘authority’, it does not mean so in the sense Mr. Ybarra thinks. “Auctoritas” does not mean ‘authority’ in the sense of juridical power (“potestas”) but instead refers primarily to soft power (i.e. the ability to convince others to do what you want them to do because of your good reputation).
…
There is no doubt Rome had an inordinately large amount of leverage and auctoritas but Mr. Ybarra makes a basic mistake here because not only does he not read any Latin or Greek, but he has no background in classics or ancient history and is therefore incapable of understanding and appreciating the particularly strong juxtaposition of the two concepts not only within Roman Law, but also Latin Patristics.1
Like many of Denny’s remarks, these are as false as they are heavy with condescension. Given his presumed expertise in classics, it’s strange that he tries to determine a priori what kind of authority Leo had—or claimed to have—on the basis of a dictionary definition severed from historical and theological context. Worse still, he included hyperlinks to Latin definitions with senses that undercut his own point.2
There are three key things to say about auctoritas and potestas.3 Contra Denny, all three tend to reinforce the Catholic view of the papacy, or at any rate none of them militate against it. Scholars understand this well, which is why Denny and his Ubi Petrus team may be the only people ever to press the auctoritas objection.
de facto and de jure
To say that a pope using auctoritas instead of potestas signals a weaker power is to miss the very structure of Christian political order in the first millennium. The distinction between the two is not between two grades of power—one soft, the other hard—but between right and might, between de jure authority and de facto power.
Auctoritas is the moral and juridical right to command. Potestas is the physical ability to enforce that command. Walter Ullmann captured it well:
Auctoritas is the faculty of shaping things creatively and in a binding manner, whilst potestas is the power to execute what the auctoritas has laid down.4
A judge has the authority to render a verdict—that is auctoritas. But he must rely on the police to carry it out—that is potestas. The one speaks with rightful rule, the other with enforceable means.
The Supreme Court is the highest judicial authority in the United States. It possesses auctoritas, not potestas—the right to judge, not the physical power to enforce. But that doesn’t make it any less supreme. Imagine saying it lacked supreme authority simply because lower levels refused to carry out its orders. You’d be confusing de jure with de facto, as online Eastern Orthodox polemicists frequently do, and you’d be wrong. Potestas without auctoritas is tyranny, not authority.5
It is the same with the papacy. The pope holds auctoritas as the successor of Peter and vicar of Christ. The Pope’s auctoritas is de jure, a right given by divine institution, not imperial concession. Whether the pope also possesses potestas—de facto power to enforce his decisions—depends on the political moment. But his authority does not rise or fall with his ability to compel obedience. What matters for papal supremacy is not whether the emperor listens, but whether the pope speaks by right. As historian Robert Louis Benson said,
The Petrine “power of binding and loosing” thus [formed] a central component of this auctoritas.6
Critics who treat the pope’s lack of potestas as a flaw confuse what’s essential with what’s secondary. As James Muldoon explains, the difference between auctoritas and potestas is illustrated by the difference between “moral authority” and “physical force.” But what matters most in Christian order is who ought to rule, not who can enforce the rules.
Language befits imperial hierarchy and procedure
And there is another point often missed. In the late Roman and early Byzantine context, where emperors wielded sweeping legal power and ecumenical councils operated within an imperial framework, it would be entirely natural—even prudent—for a pope like Leo or Gelasius to employ the language of auctoritas. Why speak in legal or executive terms when the emperor commands the legal machinery? Auctoritas offered a conceptually higher ground—morally binding, divinely rooted, and free from entanglement in imperial vocabulary. The pope's right to command does not depend on whether he shares in the empire’s potestas; it depends on his office, his succession, and his mandate from Christ.
To fault the pope for lacking the sword is like faulting the head for not being the arm. But the body obeys the head—not because the head is stronger, but because it is in charge.
The spheres of imperium and sacerdotium
Implicitly recognizing the distinction between de facto and de jure authority, Pope Gelasius I, in the fifth century, identified the two powers by which the world is governed: the sacerdotium of sacred authority (auctoritas) and the imperium of royal power (potestas). In his letter to Anastasius I, he wrote:
There are two things, august Emperor, by which this world is chiefly ruled: the consecrated authority of bishops [auctoritas sacrata pontificum] and the royal power [regalis potestas].7
Benson notes that the
episcopal auctoritas controls the “order of religion”, a preeminence which includes the administration of sacraments, and therefore a monopoly over the means of salvation.8
Pope Gelasius “regarded the separation and autonomy of imperium and sacerdotium as a ‘divinely decreed order’.”9 Thus, auctoritas is not inferior to potestas; it simply governs a separate, higher sphere:
in the “order of religion” the prince is subject to the pontiff. With his reference to the regalis potestas, however, Gelasius was indicating the emperor’s office, rather than his person, and he recognized that God had bestowed the office… Hence Gelasius accepted the emperor’s unqualified jurisdiction over bishops in the “sphere of public order”, as well as in the bishops’ obligation to obey imperial laws.10
Conclusion
Denny’s mistake about auctoritas and potestas is not just lexical—it’s conceptual. To reduce the former to soft power is to ignore how the Church understood its own structure, how popes spoke of their office, and how emperors responded to it. The distinction between the terms was not a contrast between influence and power, but between rightful command and its practical execution. The popes never needed imperial potestas to assert their role; they already possessed something greater: auctoritas grounded in divine right. That’s not a weakened authority, but authority’s source.
<https://ubipetrusibiecclesia.com/2019/09/24/was-the-tome-of-leo-ex-cathedra/>. Erick responded thoroughly to Denny’s objection in a blog post of his own, including numerous scholarly quotes, but in the debate he didn’t respond as forcefully to Denny as he could have or should have done. His blog post is well worth the read. See it here: <https://erickybarra.wordpress.com/2019/11/09/response-to-ubi-petrus-ibi-ecclesia-tome-of-pope-st-leo-critically-examined-by-the-council-of-chalcedon/>.
E.g., “Will, pleasure, decision, bidding, command, precept, decree.” While auctoritas may connote moral influence or reputational weight, it is not reducible to soft power or the exclusion of juridical force. Ironically, Denny appeals to the Lewis and Short Dictionary to support this claim, yet that very source clearly shows auctoritas can denote formal authority, binding decisions (auctoritas senatūs), legal rights, and commands (auctoritas Caesaris). Even if it we grant for the sake of argument that “soft power” is a common or even primary meaning, it is a fallacy to infer that meaning in any given case—such as Pope Leo’s Tome—merely from a dictionary entry. Context, not lexical ranking, governs interpretation.
These aren’t the only points to make, of course. Again, see Erick’s article referenced in note 1 for more.
Walter Ullmann, The Growth of Papal Government in the Middle Ages: A Study in the Ideological Relation of Clerical to Lay Power, 2nd ed. (London: Routledge, 1962), 21.
James Muldoon, “Auctoritas, Potestas and World Order,” in Plenitude of Power: The Doctrines and Exercise of Authority in the Middle Ages: Essays in Memory of Robert Louis Benson, ed. Robert C. Figueira (London: Routledge, 2006), 126.
Robert Louis Benson, “The Gelasian Doctrine: Uses and Transformations,” in La notion d'autorité au Moyen Âge: Islam, Byzance, Occident, ed. George Makdisi, Dominique Sourdel, and Janine Sourdel-Thomine (Paris: Presses Universitaires de France, 1982), 15.
Ibid., 13. This letter dates to 494 AD.
Ibid., 20-1.
Ibid., 15. Benson also notes that, according to the sacerdotal sphere, “the emperor must not judge questions of orthodoxy, nor can his recognition of (or refusal to recognize) a bishop as orthodox bind the Church or the papacy, which will decide the matter authoritatively.”