Rhetorica:
The Topoi,
IV. Authority
By Gabriel Blanchard
"To argue from authority would be beneath the dignity of theology, since 'authority is the weakest kind of proof,' according to Boethius." —St. Thomas Aquinas, Summa Theol. I.1.viii.2
That Which We Call Authority
The fourth and last of the topoi is known as testimony or authority. (Authority here primarily bears the sense “expertise,” as in Cambridge‘s third definition and Merriam-Webster‘s third and fourth.) Either name will do: On the one hand, authorities testify about their exceptional knowledge of their field, while on the other, testimony is given by witnesses, who are uniquely authoritative about what they have heard, what they have seen with their eyes, what they have looked upon, and what their hands have handled. The principal difference between the two names lies in connotation.
Richard Weaver had the following to say about the fourth topos as a whole:
The fourth category … deals not with the evidence directly but accepts it on the credit of testimony or authority. If we are not in a position to see or examine, but can procure the deposition of someone who is, the deposition may become the substance of our argument. We can slip it into a syllogism just as we would a defined term. The same is true of general statements which come from quarters of great authority or prestige. … [I]n all these cases the listener is being asked not simply to follow a valid reasoning form but to respond to some presentation of reality.1
Quandô Jûdex Est Ventûrus2
However, there can be a more practical distinction between these, a differentiation of subtypes. Last time, we discussed argument according to circumstance as a specialized subtype of the third topos; we can do the same here, especially if we have an eye to the temporal dimensions of rhetoric. The word “testimony” hints at what the judicial purposes this topos is specially relevant to—because what do we call a person who testifies? That’s right, a testificator. (Or I suppose you could say “witness,” if you’re absolutely bent on ruining the philological parallel. I don’t care. No really, it’s fine. Go ahead.)
In some ways, this subtype of the topos can be seen as the more potent of the two. Authority, if we bring in the connotations of the term, ultimately depends for its efficacy either upon force or upon trust; but when dealing with a witness, even—maybe especially—one who has no relevant expertise, we feel dimly as if we are consulting the common verdict of humanity; and it is a rare person, whether in foolishness or in wisdom, who can reject the common verdict of humanity. Of course, the reality is a bit more complicated than that: Some witnesses lie, memory is not always reliable, etc. But then, that is why this is a commonplace and not a syllogism.
The Salem gentlemen will by no means allow that any are brought in guilty and condemned by virtue of spectral evidence3 ... but whether it is not purely by virtue of these spectral evidences that these persons are found guilty (considering what before has been said), I leave you, and any man of sense, to judge and determine.
What, then, is different in the accent or style of the name “authority”?
The Gnostic Gospel
The “authority” variety of this topos is not irrelevant to forensic rhetoric, but it is more common as a device in deliberative rhetoric—and also in a fourth variety of rhetoric, not enumerated by Aristotle and therefore not usually mentioned as one of its varieties, though the man himself was a master of it: namely, what we might term instructive or didactic rhetoric.4 (Of course, asking Aristotle to notice this as a kind of rhetoric might have been a bit like asking a fish to explain water.) We often have cause to call upon expertise when making decisions, and we most certainly want it in our teachers; at any rate, we want them to be more expert than ourselves (or else what are we even doing here?).
Within religious contexts in particular, this subtype of this topos can have a unique power. The obvious example here would be that of a theological debate held among Latter-Day Saints or Catholics, or any other religious body with a professedly revelatory or infallible authority. Do take note of that preposition, “within.” It will assuredly not have the same power between people who do not all agree that the authority in question is divine. It may have less force with outsiders, or more likely none at all (like Jadis in The Magician’s Nephew trying to cast spells outside of Charn). It behooves us to close with another quotation from Weaver, discussing the potency of the four topoi relative to one another:
Arguments based on testimony and authority, utilizing external sources, have to be judged in a different way. … The question of their ranking involves the more general question of the status of authority. Today there is a widespread notion that all authority is presumptuous (“Authority is authoritarian” seems to be the root idea) … This is a presumption itself, by which every man is presumed to be his own competent judge in all matters. But since that is a manifest impossibility, and is becoming a greater impossibility all the time, as the world piles up bodies of specialized knowledge which no one person can hope to command, arguments based on authority are certainly not going to disappear. The sound maxim is that an argument based on authority is as good as the authority. What we should hope for is a new and discriminating attitude toward what is authoritative …5
1Language Is Sermonic, pp. 209-210 of the 1970 Louisiana State University Press paperback (part of the eponymous essay).
2This Latin phrase (drawn from the Diēs Iræ) means, roughly, “When the Judge shall come.”
3In the Salem Witch Trials, the judges decided to accept “spectral evidence”: claims by the ostensibly bewitched that the shape of a defendant was there in the court tormenting them, invisible to all others, by the arts of the devil. One might have expected persons who believed the devil could work such miracles to recall that the devil can also lie, and deduce that this “evidence” was therefore useless even if it were not invented by the accuser. In fact, they did: well enough to pay the idea lip service, anyway. Rev. Cotton Mather wrote in a 1692 letter to the court that “there is need of … exquisite caution, lest by too much credulity for things received only upon the Devil’s authority, there be a door opened for … Satan [to] get an advantage over us; for we should not be ignorant of his devices”—while endorsing the admission of “spectral evidence.” Thus the judges satisfied themselves of their diligent circumspection; then, they judicially murdered no fewer than twenty people.
4Teaching could, with great exertions, be crammed into the categories of forensic and epideictic rhetoric. The former would have to be stretched to cover all forms of history, including the history of every subject (a little of which is usually imparted in the course of teaching it); the latter, all disciplines referring to truths which hold either as general principles, like the sciences, or independently of time, mathematics being the purest example. However, neither the perennial nor the eternal are altogether the same thing as the present. Likewise, while instruction has similarities to praise and censure (e.g., all involve telling people what to think), it is more usefully thought of in a class unto itself.
5Op. cit., pp. 215-216. (Note that “discriminating” here bears the now-archaic sense “discerning, judicious”—just about the opposite of the typical meaning today, i.e. “bigoted, biased, chauvinistic.”)
Gabriel Blanchard is a freelance author. He lives in Baltimore, MD.
If you enjoyed this piece, first of all, thank you for reading. You might also like our series on the great ideas throughout Western history, for which we have a handy topical index. Or, if you’re looking for something to read this summer, take a look at this post by Miss Faith Walessa on seven excellent volumes of literature (soon to be accompanied by one on seven nonfiction books, for those of you with a taste for “reality,” or whatever kids are into nowadays).
Published on 17th July, 2025. Page image of a sixth-century mosaic in the Church of St. Vitalis in Ravenna, Italy, depicting the Emperor Justinian with attendants. Photo by Roger Culos, used under a CC BY-SA 3.0 license (source).
