Ab —, Ad —, Ex —: Latin Labels

Latin labels are used to name arguments and fallacies. This practice, although not systematic, is common in modern texts, not exceptional in law, and some traces remain in contemporary usage.

A few of these labels belong to the usual vocabulary of argumentation theory:

argument ad hominem, a fortiori, a contrario, a pari

The English counterpart of the Latin word is often transparent:

argument e silentio, argument from silence.

Nonetheless, some labels remain opaque when one is not familiar with Latin:

argument ad crumenam, argument to the purse.

The current translation of these Latin labels may be questionable. The label argument ad verecundiam is often translated as “argument from authority”, while the Latin word verecundia means “modesty, humility”. For Locke, who introduced this label, the ad verecundiam argument is not precisely a sophism of authority but of submission to authority, S. Modesty.

This terminology is no longer spontaneously understood. In many cases, this piecemeal Latin appears gibberish and even ridiculous, particularly when well established, or more readily understood English terms can be used to refer to the same argument scheme.

This continued use of Latin labels, however, is due to the power of Latin as the language of law, theology, philosophy and traditional logic. This designation system for argumentation parallels the one which is well established and currently used for the designation of rhetorical figures. Latin has provided a common technical language for everyday reasoning, whilst giving the theoretical discourse some fragrance of Ciceronian authority. This use of Latin is altogether comparable to the contemporary use of English in countries where English is not the native language.

Three main types of Latin phrases can be distinguished.

1. Prepositional labels using the prepositions ab /aadex

Some arguments or fallacies are designated, in contemporary texts, by prepositional phrases having the following structure:

Latin Preposition + Latin Noun + argument

Sometimes, the Latin word “argumentum” replaces argument.

Latin is an inflected language; in prepositional phrases, the preposition imposes a specific grammatical case on the following noun, marked by a morphological variation at its end.

The three most used prepositions are ab, ex, and ad.

— The preposition ab (or a before consonant) means “from, pulled of, drawn from”:

a contrario argument, argument from the contrary.

—The preposition ad, means “to, towards, for »:

ad personam argument, argument to the person.

— The preposition ex means “from, out of”, indicating the origin:

Argument ex datis: argument drawn from what is admitted by the audience.

Ex labels are less common.

Occasionally, other prepositions can be found:

per: per analogiam argument, argument by analogy;
in: argument in contrarium, argument from the opposites;
pro: argument pro subjecta materia, argument relative to the subject matter. S. Subject matter.

From a semantic point of view, there is a directional contrast, origin vs. purpose, between the prepositions ab and ex on the one hand, and ad on the other hand:

ab, ex + Latin noun + argument = argument based on —, using —
ad + Latin noun + argument = argument targeting —.

Ab, ad and ex compete in the designation of some arguments, with the same meaning:

ab auctoritate or ad auctoritatem argument;
ab absurdo or ad absurdum or ex absurdo argument.

The argument schemes designated by each of these labels have no common semantic basis. Many ad tags have been introduced in the modern period. Sometimes, they  refer to very specific contents, in particular, to appeals to emotion or to a subjective position, whilst the labels ab and ex are never used in this sense.


The following entries list the Latin labels according to the preposition head of the noun phrase, give some equivalent of the Latin terms, and refer to the corresponding entry or entries:

Ab — Arguments (A Contrario, etc.)
Ad — Arguments (Ad Ignorantiam, etc.)
Ex — Arguments (Ex Concessis, etc.)

These lists are taken from Bossuet ([1677]), Locke ([1690]), Bentham ([1824]), Hamblin (1970); Perelman & Olbrechts-Tyteca ([1958]), and from the Internet. They do not claim to be exhaustive.
Modern Latin labels are presented along with ancient ones, as they were used by Cicero, Quintilian and Boethius, and sometimes incorporated unchanged by modern authors. Examples of this original terminology may be found under the entry Typologies (II): Ancient.

2. Other Latin phrases

Less frequently, various Latin phrases are used to refer to classical Aristotelian fallacies:
— Fallacy of omission of relevant qualification or circumstances; undue generalization of a limited claim:

Fallacy a dicto secundum quid ad dictum simpliciter: a reasoning concluding from a qualified statement (limited in scope) to a generalizing statement (absolute).

Lat. dictum “word; maxim; sentence” here: “assertion”; Lat. secundum quid “according to something”; Lat. simpliciter, from simplex, “simple”.

This formula is abbreviated as “secundum quid fallacy”, S. Circumstances.


— Fallacies of false cause, that is to say, of poor construction of the causal relation, S. Causation; Cause-Effect: The causal link:

Non causa pro causa: “a non-cause is taken for a cause”. E1 is said to be the cause of E2, although this is not the case.
Cum hoc, ergo propter hoc: “At the same time as, thus because of ”.
From the fact that E1 and E2 are concomitant, one wrongly infers that they are causally linked.
Post hoc, propter hoc ergo: “later, thus because of”: from the fact that E1 always occurs before E2, one wrongly infers that E2 is due to E1.

— Fallacy of vicious circle:

Petitio principii, Lat. petitio, “demand”; principium “principle”: “request to grant (something equivalent to) the claim which is actually disputed”

The language of law uses Latin phrases and expressions to refer to argumentative principles, for example:

eiusdem generi: lat. idem, “the same”; genus, “genus”. Argument from the identity of genus; S. Genus; Juridical arguments.

3. A mocked pattern

In Tristram Shandy, Sterne mentions the arguments ad verecundiam, ex absurdo, ex fortiori, ad crumenam and the argumentum baculinum (ad baculum) and asks to add to this list the argumentum fistulatorium, which he claims to have invented.

— There lies your mistake, my father would reply; — for in Foro Scientiae there is no such thing as MURDER, —’tis only DEATH, brother.
My uncle Toby would never offer to answer this by any other kind of argument, than that of whistling half a dozen bars of Lillabullero.—–You must know it was the usual channel thro’ which his passions got vent, when anything shocked or surprised him; — but especially when any thing, which he deem’d very absurd, was offerd.

As not one of our logical writers, nor any of the commentators upon them, that I remember, have thought proper to give a name to this particular species of argument, — I here take the liberty to do it myself for two reasons. First, That in order to prevent all confusion in disputes, it may stand as much distinguished for ever from every other species of argument — as the Argumentum ad Verecundiam, ex Absurdo, ex Fortiori, or any other argument whatsoever: — And, secondly, That it may be said by my children’s children, when my head is laid to rest, — that their learn’d grandfather’s head has been busied to as much purpose once, as other people’s; — That he had invented a name, — and generously thrown it into the TREASURY of the Ars Logica, for one of the most unanswerable arguments in the whole science. And, if the end of disputation is more to silence than convince, — they may add, if they please, to one of the best arguments too.

I do therefore, by these presents, strictly order and command, That it be known and distinguished by the name and title of the Argumentum Fistulatorium, and no other; — that it rank hereafter with the Argumentum Baculinum and the Argumentum ad Crumenam, and for ever hereafter be treated of in the same chapter.

As for the Argumentum tripodium […] Laurence Sterne The Life and Opinions of Tristram Shandy, Gentleman [1760]1

Lillibullero is a famous Irish march; the fistula is a panpipe (Gaffiot, Fistula). Uncle Toby’s maneuver is an excellent, although rude, strategy to annihilate a discourse, S. Destruction of discourse; Dismissal.

1 In The Complete Work ofLaurence Sterne. Delphi Classics, 2013. P. LV