1. Argument portant sur la réalité des choses. 2. Argument portant sur la question
débattue.

• Lat. ad rem ; rem est l’accusatif du substantif res, 1. « objet, être » 2. « affaire judiciaire, litige » (Gaffiot, Res).L’argument ad rem peut être défini de deux façons.

1. Dans le premier sens de res “réalité”, l’argument ad rem est un argument qui s’attache à “la réalité des choses”. C’est sans doute dans ce sens que Whately assimile l’argument ad rem à l’argument ad judicium de Locke.
Dans une perspective essentialiste, on peut aussi comprendre que l’argument ad rem est celui qui porte sur l’être des choses.

2. D’autre part, res peut désigner « l’affaire judiciaire, le litige » (Gaffiot).
[Res] renvoie nettement à un débat dans les expressions nihil ad rem “ce n’est pas la question” et quid ad rem ? “qu’importe ?”. Ces expressions servent à rejeter une intervention comme sans pertinence.
En ce sens, l’argument ad rem est un argument qui s’appuie sur un fait [res] pertinent pour la cause [causa], sachant que certains faits liés à l’acte matériel donnant lieu à un litige peuvent ne pas entrer dans la cause.
V. Fond.

L’opposition a contrario vs a pari

Deux topoi antagonistes

D’un point de vue logique, l’argument a contrario s’oppose à l’argument a pari. D’une façon générale, le fait que deux topoï appliqués à une même donnée livrent des conclusions contradictoires correspond à une situation banale en argumentation. Considérons la relation père / fils ; on reconnaît telle qualité au père. Que peut-on en conclure pour le fils ?

— Par le topos de la causalité génétique, le fils hérite de la qualité du père, V. Métonymie :

Tel arbre, tel fruit ; tel père tel fils, les chiens ne font pas des chats, bon sang ne saurait mentir:
Le père est riche financier et le fils habile trader.

— Par le topos des contraires, le fils hérite du défaut, et non pas de la qualité, contraire :

À père avare, fils prodigue, et non pas à père avare fils généreux

L’opposition a contrario / a pari en situation argumentative

.1 Fusionner deux catégories / distinguer deux catégories

La symétrie logique a pari vs a contrario se défait lorsque a pari et a contrario apparaissent sous une question argumentative sérieuse, structurée par l’existence d’une charge de la preuve.

Situation :        Les A et les B reçoivent des traitements différents (S)
Question :       Les A doivent-ils être traités comme les B ?
Proposition :    Oui. Les différences entre les A et les B sont négligeables / non pertinentes pour notre discussion. Les A et les B doivent être traités a pari.
Opposition :      Non. Les différences entre les A et les B sont essentielles / pertinentes pour notre discussion. Les A et les B doivent être traités a contrario.

Dans la situation (S), le proposant se sert de a pari pour défaire l’opposition, alors que l’argument a contrario est l’argument de l’opposant qui soutient le statu quo, avancé par l’opposant.
Le proposant s’attache à minimiser l’opposition, alors que l’opposant la maximise.

Soit une situation où certaines personnes sont traitées comme des égaux en droit alors qu’ils ne le sont pas de fait.
Le proposant prend acte de l’inégalité de fait, considère que la différence de traitement de fait est indéniable, et propose la création d’une nouvelle catégorie, celle des gens qui ne luttent pas à armes égales.
L’opposant cette fois utilisera a pari pour maintenir le statu quo et s’opposer à l’innovation, en minimisant la différence et en disant que la proposition est discriminatoire

Exemple

Soit une phratrie composée de garçons et de filles, deux espèces du genre “adolescent”. Les garçons sont autorisés à sortir le soir, mais pas les filles. Considérons la situation où cette interdiction de sortir le soir pèse aux filles. Elles peuvent argumenter de multiples façons, par exemple par les conséquences positives qu’auront les sorties nocturnes sur la formation de leur conscience sociale, V. Pragmatique. Elles peuvent également observer que leurs frères sortent, et utiliser un elliptique a pari :

F : — Les garçons sortent bien tous les soirs !

L’ontologie des filles est la suivante :

Genre : adolescent, enfant d’une même famille…
Espèces : {garçon, fille}
“Sortir le soir” est une propriété attachée au genre adolescent, (non pas à l’espèce garçon)
Toutes les espèces peuvent donc s’en réclamer.

Sans surprise, certains parents répondent a contrario :

P : — Oui, mais vous, vous êtes des filles !

Leur ontologie est la suivante :

Genre : adolescent
Espèces : {garçon, fille}
Différence : masculin / féminin ; la différence de genre est construite comme spécifique.

Par une argumentation par la définition, “sortir le soir” apparaît comme une licence attachée à l’espèce “garçon”, elle fait partie de sa définition. La propriété ne peut être transférée, car elle est une différence liée à l’espèce en tant que telle. L’argumentation a pari fondée sur le genre commun est donc bloquée.

Si a contrario radicalise les oppositions catégorielles, a pari les efface. Il y a donc une solution pour les filles: il leur suffit d’effacer la différence, et de reconstruire sous le genre une catégorie unique, qui permettra de revendiquer l’application de la règle de justice, et pour cela elles doivent :

(i) Construire une nouvelle catégorie, “comme les garçons”, en agissant sur deux fronts.

— Maximiser les activités communes aux garçons et aux filles :

Les garçons et les filles reçoivent la même éducation ; ils et elles ont accès aux mêmes médias ; ils et elles font du judo ; l’école a les mêmes exigences vis-à-vis d’eux et d’elles ; ils et elles partagent les mêmes tâches à la maison et se préparent aux mêmes professions…

— Réduire la différence :

“Quand je sors, je suis un garçon” : La question d’être un garçon ou une fille n’est pas un fait biologique, mais un choix d’identité personnelle, qui ne peut (donc) pas motiver une telle interdiction.

(ii) Raisonner par la définition dans cette nouvelle catégorie. La différence, qui à l’intérieur d’un même genre, en séparait les espèces et permettait le fonctionnement de a contrario, est annulée par la création de cette nouvelle catégorie, où la différence biologique est considérée comme socialement non pertinente.

Le texte suivant reproduit celui d’une affiche publiée à Paris pendant la Révolution française contre le « Décret du marc d’argent ». Ce décret, dont il est question ligne 11, fait partie d’un ensemble de dispositions prises par l’Assemblée Constituante (1989 – 1791) organisant le suffrage censitaire masculin pour les élections à l’Assemblée législative qui lui succèdera en 1791. Ce mode de suffrage prévoit que, pour être “citoyens actifs”, c’est-à-dire simple électeur aux assemblées primaires, il faut s’acquitter d’un impôt d’un certain montant, et d’un impôt équivalent à « un marc d’argent » pour être éligible. Les “citoyens passifs” ne sont ni électeurs ni éligibles. Cette disposition soulève beaucoup d’opposition, dont la pétition suivante.

Pétition à l’Assemblée Nationale

Les soussignés, réunis en Comité Central des diverses Sociétés Fraternelles de la Capitale, qui veillent au salut de la chose publique, viennent de se convaincre que le jour qui doit voir commencer les Assemblées primaires, sera le signal de la réclamation universelle de ceux auxquels on a ravi toute espérance.

PÈRES DE LA PATRIE

Ceux qui obéissent à des lois qu’ils n’ont pas faites ou sanctionnées sont des esclaves.

Vous avez déclaré que la loi ne pouvait être que l’expression de la volonté générale, et la majorité est composée de citoyens étrangement appelés inactifs.

Si vous ne fixez les jours sacrés de la sanction universelle de la loi par la totalité absolue des citoyens ; si vous ne faites cesser la démarcation cruelle que vous avez mise par votre Décret du marc d’argent, parmi les membres d’un peuple-frère ; si vous ne faites disparaître à jamais ces différents degrés d’éligibilité qui violent si manifestement votre Déclaration des Droits de l’Homme, la Patrie est en danger.

Au 14 juillet 1789,

La ville de Paris contenait trois cent mille hommes armés, la liste active publiée par la Municipalité, offre à peine quatre-vingt mille citoyens.

Comparez et jugez !

L’argumentation ad hominem, distincte de l’attaque personnelle, (ad personam) met en crise une personne ou une institution en lui opposant ses propres actes, dires, ou décisions.

Vous avez déclaré que la loi ne pouvait être que l’expression de la volonté générale, et la majorité est composée de citoyens étrangement appelés inactifs. (Lignes 7- 8)

En théorie, la personne ou l’institution ciblée peut choisir de répondre qu’elle a changé d’avis, ou accepter la remarque et réajuster ses actes, en rectifiant l’un ou l’autre terme de la contradiction. Ici, il n’est pas question pour les auteurs de la pétition de revenir sur le fait que « la loi ne [peut] être que l’expression de la volonté générale », mais de rejeter tout suffrage censitaire. Il s’agit de « [faire disparaître à jamais » une mesure parce qu’elle « [viole] » un principe de la Déclaration des Droits de l’Homme précédemment votée par cette même Assemblée Nationale.

Le rappel de la journée du 14 juillet appuie cette argumentation d’une encore discrète menace – argumentation par les conséquences qu’aurait le maintien du décret.

Les deux termes de la contradiction ne sont pas maintenus dans un équilibre abstrait. On retrouve pour ad hominem le problème de fausse symétrie entre les deux termes opposés, qui conduit à l’impasse l’analyse “logique” (décontextualisée) de a pari et a contrario.

1. L’argument par la conséquence, ad consequentiam

Le mot latin consequentia signifie :

1. 1. “Ce qui vient après”, dans l’espace ou dans le temps.
   2. La conséquence causale ou logique : per consequentias, « par voie de conséquence » (d’après Gaffiot, Consequentia) Voir Walton 1999 [1]

Dans la première acception, l’argument ad consequentiam fait référence à quelque chose qui a succédé temporellement à un événement central. Par exemple, une grosse somme d’argent a été volée à Paul. L’enquêteur note qu’après la date du vol, Jacques, une connaissance de Paul, a dépensé de grosses sommes d’argent, alors que rien n’a changé dans ses revenus. L’enquêteur peut utiliser ce qui s’est passé après (le vol) pour accuser Jacques du vol. V. Circonstances.

Dans la seconde acception, un argument ad consequentiam est un argument fondé sur des conséquences causales ou logiques.
— Effets matériellement liés à une cause. Dans ce sens, l’étiquette ad consequentiam couvre toute la gamme des diverses argumentations fondées sur les conséquences (argumentations remontant de l’effet à la cause).
Ainsi, l’argument pragmatique faisant appel à des conséquences positives ou négatives s’appuie sur une argumentation ad consequentiam.
— Conséquences logiquement déduites d’une hypothèse. Les réfutations par l’absurde se fondent sur des conséquences jugées absurdes d’un point de vue logique (elles conduisent à une contradiction).

2. Argumentation ad consequentiam et argumentation pathétique

L’argumentation ad consequentiam peut être est définie comme suit (Wiikipedia, Ad consequentiam)  :

L’argument par la conséquence, (Lat. Argumentum ad consequentiam), est un raisonnement fallacieux. Il consiste à déduire une conclusion  (en général une croyance) à partir d’une conséquence  positive ou négative, de la croyance à prouver.
Cette erreur vient du fait que l’on refuse d’admettre les conséquences désagréables d’une proposition, même si elle est vraie. Ou à l’inverse qu’on est tenté d’accepter les conséquences agréables d’une proposition fausse. Mais que les conséquences [soient] agréables ou désagréables ne constituent pas une preuve.
Dieu doit exister : s’il n’existe pas, alors de très nombreuses personnes prient pour rien !

L’étiquette “argumentation par les conséquences” (ad consequentiam) sert de terme générique pour couvrir les schèmes argumentatifs remontant de la conséquence — de l’effet — de ce qui succède jusqu’à sa cause — sa raison — ce qui le précède.
Le schème précédent correspond à un cas particulier de l’argumentation par les conséquences, que l’on peut désigner de façon plus spécifique comme une argumentation pathétique.

[1] Douglas Walton, 1999. Historical Origins of Argumentum ad consequentiam. Argumentation 13(3), 251-264.

L’analogie, l’autorité, la causalité, la définition… mettent en jeu deux types d’argumentations, (1) l’argumentation qui établit l’existence d’une analogie, etc. ; (2) l’argumentation qui exploite une relation d’analogie qu’elle présuppose.

L’analogie, l’autorité, la causalité, la définition… sont des ressources argumentatives fondamentales. On les retrouve dans les typologies de Cicéron (1er siècle avant J.-C., V. Typologies – Anciennes) ainsi que dans celles de Janik, Rieke et Toulmin (20e siècle de notre ère, V. Typologies – Contemporaines).

Les arguments relatifs à ces sources peuvent être divisés en deux catégories principales.

(1) Arguments établissant (construisant, justifiant…) l’affirmation que :

— Il existe une relation de causalité entre deux faits.
— Il existe une analogie entre deux êtres ou deux organisations de la réalité,
                    V. Catégorisation ; Analogie catégorielle ; Analogie structurelle
— Telle source fait autorité, V. Autorité, §7.3
— Telle définition définit correctement tel mot, ou tel concept.

(2) Arguments exploitant :

— Une relation causale préétablie (présupposée, bien connue…),
                   V. Arg. de la cause à l’effet ; Arg. de l’effet à la cause ; Arg. pragmatique.
— Une relation analogique préétablie (présupposée, bien connue…),
                   V. Analogie catégorielle ; Analogie structurelle
— Une source reconnue faisant autorité, V. Autorité, §6-7
— Une définition acceptée,
                    V. Arg. par la définition.

Ce deuxième type d’arguments peut être réfuté au motif que l’affirmation sous-jacente du premier type qu’il présuppose n’est pas correcte.

Arguments « fondés sur / établissant la structure de la réalité »
(Perelman & Olbrechts-Tyteca)

La distinction précédente est différente de celle que l’on trouve dans le Traité de l’argumentation entre « Argument fondé sur la structure de la réalité » ([1958], §60-77) et « Relations établissant la structure de la réalité » ([1958], §78-88), V. Typologies (3).
Selon Perelman & Olbrechts-Tyteca :

— Les arguments causaux et l’autorité sont «fondés sur la structure de la réalité».
— L’analogie est une relation « établissant la structure de la réalité ».
— La définition est une relation « quasi-logique ».

Bachelard
Benveniste

The adjective vague qualifies communicated meaning. Vague is opposed to clear, definite, explicit, specific (MW). The default orientation of vague is negative, while the orientation of each of its antonym is positive.

1. Vagueness, Precision and Relevance

1.1 The intention / extension quandary

General is opposed to specific, and individual. General terms have a broader extension / narrower intension than specific terms. The extension of a term is the set of individuals to which this term can refer, the intension of a term corresponds to the meaning of this term, S. Definition (1). Hypernyms and covering terms (1) are more general / less specific general than their subordinate terms.

Extension and intension vary in opposite directions. When intension increases, that is, when the definition is extended, more cases are covered, there is a gain in generalization; correlatively, extension increases and there is a loss in precision.
Vice-versa, when the definition is restricted, less cases are covered, there is a gain in precision; correlatively, extension decreases and there is a loss in generalization.

 Generalization is ambivalent. It is considered as positive move when it shows that a concept, a theory, a method… applies to new cases, different from those originally envisioned. Their scope is wider than foreseen; their claims are not ad hoc, that is limited to one original case and saying nothing beyond the individual features of that claim. Having a potential for generalization shows that the method is fertile.

But an extended concept is more exposed to refutation than a restricted one. Overgeneralization occurs when that kind of extension fails, for two reasons:
—  The new cases clearly fall outside of the scope of the original claim; the theory has nothing to say about them.
— The new definition says nothing but trivialities about the new beings or new facts that it claims to cover.

1.2 Generality, Ambiguity and Vagueness

A term G is more general than another term S if its extension is broader than that of S, and its intension smaller.

Generic terms are general words designating a genus encompassing several species. Species are designated by more specific terms, which add specific differential features to their generic features. This addition in its definition restrict the number of individuals to which the word can refer.

Cover (covering) terms, or umbrella terms are general words whose meaning encompass the common features of various other terms. The covering term is used in order to focus on the common points of the covered terms, or as a current word referring to specialized words.
The relations between generic and specific terms are regulated by the strict organization in genus and species.  The covering / covered terms relations, the links and oppositions between covered terms, depends on the field considered. An umbrella term can refer to a simple enumeration of elements.

Emotion is a covering term for joy, fear, hate, love, etc.

Cardiovascular disease is an umbrella term for a set of health issues that affect the heart and/or blood vessels. [1]
myocardial infarction – cerebrovascular accident – arteriosclerosis – angina pectoris – heart failure – cardiac arrhythmia – high blood pressure.

The binary anatomical categorization of masculine/feminine genders and sexualities is replaced by the seven self-identified orientations, their acronym LGBTQIA+ serving as umbrella term for:
lesbian, gay, bisexual, transgender, queer, intersex, asexual, and more.

A general term is not an ambiguous term. The word dog is not ambiguous between the different names of dog species (bulldog, poodle, hound, etc.).

A general term is not a vague or obscure term.  The information it communicates applies to a large number of beings or to a variety of cases. For example, the word accident is a covering term referring to a variety of situation: road accident, accident at work; domestic accident; medical accident, etc. Nonetheless, “It was an accident” is precise and valuable as the first available piece of information. Precisions will come later, if needed. As an excluder, “it was an accident” is perfectly precise, since it excludes “it was a crime”.
It can be considered insufficient only in reference to the relevance principle organizing the current conversation, for example, if it only says what everybody can see.

A general term is not a collective term. Nouns like set, heap, group, herd, team, collection… are collective terms. In the singular, they refer to a set of objects or individuals taken as a relatively stable whole; in the plural, they refer to several distinct sets of this type. They are characterized by the fact that they have no upper limit.

1.3 Vague vs Precise vs Relevant

Generalities are said vague, irrelevant, when they do not contribute to the specific task under way.  They just allow the speaker to dodge the common task, and adopt a non-committed stance towards the issue.
Information can be said to be fuzzy, vague, or on the contrary precise. According to Grice’s quantity principle, the precision of information is relative to the conversation it keeps alive. this principle requires that exactly the right amount of information be provided, no more and no less, S.. Cooperation principle.

Three friends look at a  splendid car going by:
L1:       How much does a nice car like may cost?
L2:       (i) At least 50,000 euros, I think
(ii) Not necessarily more than 25,000 euros
L3:       (i) 58225 euros before tax, plus options
(ii) 23112 euros before tax, plus options

The answer L2 (i) is neither unclear nor vague but sufficient. It gives an order of magnitude that is perfectly appropriate to the thread of the conversation, to which it gives it a clear orientation, « you still have to make some money to have a car like that!« .
L2 (ii) would give points to another orientation, “If you really want it, you can afford it« .
L3 is more precise, but the degree of precision is irrelevant to the conversation. Whatever the preceding topic were, it was not about the exact price of that car.

A buyer to a seller:
L1:       And this model, how much?
L2:       Around 50 000 euros
L3:       58225 euros before tax, plus options.

L2’s answer is now vague, in the sense of « insufficient ». It does not give the exact price, corresponding to the amount of the check the buyer will have to write. L3 fully answers L1’s question.
The vague / precise character of an intervention depends on the circumstances of the conversation and on the action cooperative or antagonistic, developed by the participants.

2. Fuzziness as a zone open to discussion

2.1 Indeterminacy of inter-categorical boundaries

Belonging to a category can be defined with reference to a set of beings typically belonging to the category. One must then distinguish, at the periphery of the clear-cut zone that gathers the prototypical beings of the category, an increasingly blurred zone occupied by borderline objects, belonging less and less to this category, and more and more to another one.

A hammock certainly qualifies as a kind of bed; a beach towel not really; an inflatable mattress certainly, if it is intended for the guest room, but less clearly if it is part of the pool equipment, etc.

The arguments a pari, a contrario, from the opposite play on the phenomena of continuity / discontinuity of the categories, by privileging the attachment of a being to such category or to such other. This border zone is a zone of discussion.

2.2 Fuzziness as a deliberative zone

Peirce (1902) defines the word vague in relation to the variations of judgment of the speakers.

Vague (in logic) [Lat, vagus, rambling, indefinite]: Ger. unbestimmt ; Fr. vague ; Ital. vago. Indeterminate in intention.
A proposition is vague when there are states of things concerning which it is intrinsically uncertain whether, had they been contemplated by the speaker, he would have regarded them as excluded or allowed by the proposition. By intrinsically uncertain we mean not uncertain in consequence of any ignorance of the interpreter, but because the speaker’s habits of language were indeterminate; so that one day he would regard the proposition as excluding, another as admitting, those states of things. Yet this must be understood to have reference to what might be deduced from a perfect knowledge of his state of mind; for it is precisely because these questions never did, or did not frequently, present themselves that his habit remained indeterminate.

Peirce considers vagueness as an issue in individual psychology, and that the wandering of judgments is related to the fact that situations of vagueness are « infrequent”, which is debatable.

Fuzzy logic formalizes the notion of fuzziness as a border zone where two categories merge. For example, on the temperature scale, the zone “the weather is nice” overlaps the zones “it’s cold” and “it’s hot”. The situation can be described not as a variation in individual judgments but as a variation in inter-individual judgments. Such variations can lead to discussions, not necessarily futile, about the weather. Fuzzy zones correspond to argumentative zones:

Representation (after Quiroga Aranibar, 1994, p. 9):

Unanimity of judgement:       1: cold — 3: nice — 5: hot
Discussion:     2: cold / nice — 4: nice / hot

Within the zone corresponding to the lexemes cold resp. hot, the intensifier very defines two argumentative subzones, cold / very cold and hot / very hot to which the same representation applies.

Vagueness does not necessarily reflect the indeterminacy of individual judgments, but the disagreement between interindividual judgments, possibly each firmly entrenched.

Quiroga Aranibar, Luis Alfonso, 1994. Learning fuzzy logic from examples. PhD, Ohio University.
https://etd.ohiolink.edu/apexprod/rws_etd/send_file/send?accession=ohiou1176495652&disposition=inline

[1] https://www.pro-activ.com/en-gb/heart-and-cholesterol/heart-health/what-is-cardiovascular-disease

1. Meaning and Unmeaning

Logical, formal and scientific languages are distinguished from natural language by their univocity and stability.To each signifying chain (term or expression), simple or complex, corresponds one and only one meaning. There is no need for interpretation.
Their meaning is not influenced by the context. It remains stable it throughout any speech developped in the domain of reference.
Such chains are neither void of meaning (nonsense), nor obscure, vague, or ambiguous (multiplicity of meanings)

In ordinary language, the interpretability of signifying chains is not guaranteed. A signifying chain of existing words  can be syntactically well formed and nonetheless:

– Meaningless, or uninterpretable (nonsense).

In the most extreme case, it is impossible to attribute any plausible meaning to the linguistic segment, that is, it cannot receive any satisfactory paraphrase acceptable or relevant in this context. It is inoperable by the receiver, interpretation is powerless.
The chain can nevertheless be explained away as a a poem, as a coded language, as a metaphor, as the product of search for meaninglessness

Colorless green ideas sleep furiously (Chomsky)

– Obscure, enigmatic, weakly meaningful.
It is difficult to formulate any interpretation; or it admits of several equally weakly motivated and inconclusive interpretations. S. Interpretation, Hermeneutics, Exegesis.

– Ambiguous.
The discourse admits of two or more clearly distinct and incompatible interpretations, S. Ambiguity.
The coexistence in the same discourse of incompatible orientations is a major cause of pragmatic obscurity.

– Vague.
Vagueness appears about borderline inter-categorical phenomena. Vagueness can also be related to over-generalization making the discourse irrelevant for the specific issue under discussion, S. Vague

– Unstable.
The meaning of the same string can vary or become obscured, in the same discourse, S. Syllogism; Ambiguity.

These are the some of the perils of natural expression, when compared with the rigorous requirements of scientific discourse. The plasticity of meaning in ordinary discourse certainly makes natural language a tricky environment for the development of scientific reasoning.
On the other hand, this same plasticity makes that natural language can generate other forms of language, S. Demonstration and argumentation.

Logical languages develop according to its own laws, scientific  language according to  the law of “things themselves ».
Natural discourse develop under the constraints of its own laws, the pressure of reality, and according to the specific needs,  interests, values that makes up the speaker’s subjectivity.
The above mentioned “perils of expression” are first of all  resources for the covert intentions and indirect motives,  ruse and crafts of the speaker.

2. Argumentative exploitation of semantic uncertainty: Fallacies of confusion

The feeling of indeterminacy is materialized by a judgment carried by the audience, or by the speaker herself, considered the first member of her audience.  Like the judgment of clarity, it can vary with the hearer.

In the case of argumentative speeches, the uncertainty judgment made on a speech is an evaluative judgment that serves to refute it as fallacious, S. Rules.

Rule 3. All expressions which are unmeaning or without effect in regard to the subject in debate should be strictly avoided.
Levi Hedge 1838, « Rules for Honorable Controversy”

Commandment 10, Language use rule: Discussants may not use any formulations that are insufficiently clear or confusingly ambiguous, and they may not deliberately misinterpret the other party’s formulations.
van Eemeren, Grootendorst “Ten Commandments for Reasonable Discussants” (2004, p. 190).

The discourse is criticized as

“unmeaning”, that is, “ lacking intelligence, vapid ” and “ having no meaning, senseless” (MW).
“insufficiently clear”
“confusingly ambiguous”.

The interpretive condition, “they may not deliberately misinterpret the other party’s formulations” guarantee the fairness of the criticism

These fallacies belongs to the “fallacy of expression” family. They target the semantic roots of the discourse, S. Discourse destruction.

Under this verdict, the  discourse is dismissed as semantically void, logically unassessable, so irrelevant for the discussion and interactionally rejected. Like all evaluative judgments, these judgments, valid or not, can be disputed and need justification.

The meaning of a discourse is the product of an activity of expression (rhetoric) and an activity of interpretation (hermeneutics). The feeling of uncertainty of the meaning, can thus have its source in the uncertainty/ruse of the expression (proponent side) or of the interpretation (opponent side).

ATCCT

Huan T’an (43 BCE. – 28 CE.), Sin-Lun (“New Treatise”) 

Pokora Timoteus, 1975 Sin-Lun (“New Treatise”) and Other Writings by Huan T’an (43 B.C. – 28 A.D.). An Annotated Translation with Index. Ann Arbor Center for Chinese Studies The University of Michigan. P. 124

 [135A] Kung-sun Lung was a dialectician who lived at the time of the Six Kingdoms. He wrote a treatise on “Hard and White” and, to illustrate his theory, said that a white horse is not a horse. To show that a white horse is not a horse, he said that “white » is that by which one names the color and horse that by which one names the form. The color is not the form, and the form is not the color.

[135B] Kung-sun Lung often argued that “a white horse is not a horse”. People could not agree with this. Later, when riding a white horse, he wished to pass through the frontier pass without a warrant or a passport. But the frontier official would not accept his explanations, for it is hard for empty words to defeat reality. (fragment 135B)

Pokora  1975, Sin-Lun (“New Treatise”), p. 124

Pa Kin, Famille. Traduit du chinois par Li Tche-houa et Jacqueline Alezaïs. Paris, Flammarion, 1979.

Le surlendemain […eut lieu la révision des articles pour le n°8. Le cadet y assista comme d’habitude. Á son arrivée, Telle que Sourire lisait à haute voix une proclamation de la police interdisant aux femmes de porter les cheveux courts. Le jeune homme la connaissait déjà; elle était, disait-on, l’œuvre d’un talent en fleur (¹) de l’ancienne dynastie. Le fond, simpliste, et la forme même, peu correcte, suscitaient à chaque phrase la gaieté de tous les auditeurs.
— C’est vraiment se moquer des gens! Que veut-il dire? s’écria Telle que sourire en jetant la feuille à terre.
— On pourrait publier ce chef-d’œuvre dans le prochain numéro sous la rubrique « Histoire de rire”, proposa Réserve de bienveillance.
— Bravo ! applaudit la jeune fille.

Tous approuvèrent. Telle que grâce ajouta qu’il serait bon de joindre une réfutation cinglante.

(¹) Titre officiel des anciennes dynasties, traduit généralement par le terme : bachelier.

Excerpt from Ba Jin, Family (Chia)

Two days later […] the revision of the articles for the next issue of the magazine took place. The youngest attended as usual. When he arrived, Such as smile read aloud a police proclamation forbidding women to wear their hair short. The young man was already familiar with it; it was said to be the work of a blossoming talent (1) of the ancient dynasty. The content, simplistic, and even the form, not very correct, aroused the gaiety of all the listeners at each sentence.
— This is really making fun of people! What does he mean? exclaimed Such as smile, while throwing the sheet on the ground.
— We could publish this masterpiece in the next issue under the heading « Let’s laugh a bit », proposed Reserve of benevolence.
— Bravo! applauded the girl.

All approved. Such as grace added that it would be good to attach a scathing refutation.

(1) Official title of the ancient dynasties, generally translated by the term: bachelor.
Translation adapted from www.DeepL.com/Translator (free version)

1. Probable: truth and manipulation

1.1 Probable as presumptive

The word probable has the following synonyms:

believable, credible, creditable, likely, plausible, presumptive (MW, Probable)

The use of these apparenty quasi-synonyms as concepts in argumentation theory first requires a clarification of their semantics. They combine the following semantic lines (adapted from MW),

1. Sth. defined in relation with things themselves (ad rem)
— “Supported by evidence strong enough to establish presumption but not proof”: Probable, presumptive.
— “Embryonic”; Awaiting confirmation: Presumptive, credible, creditable.

2. Sth. that can be acted upon: presumptive; credible, creditable.

3. Sth coherent with past experience: “Capable of being believed, especially as within the range of known possibility or probability”:  believable.

4. Sth. that receives public approval: creditable – plausible (etym.).

So, the claim « X is probable” is a provisional statement. Something is said to be “probable” when it is supported by good reasons, good enough to act upon. The speaker is nonetheless aware of possible objections or rebuttals, and still looking for confirmation and rectification, so he should have a plan B in his pocket. The probable it is not a stopping point but a stage in an on-going research or action, connected with past experience and future action.
Enthymemes based on a “probability”, S. Enthymeme

1.2 Probable as believable

Verisimilar is not mentioned among the synonyms of probable in MW, but probable is the defining synonym of verisimilar as “having the appearance of truth”. Verisimilar introduces the key feature of similitude, that is structural analogy. It can actually be connected with the four preceding semantic lines, plausible marking the transition from probable to verisimilar.
Similitude appears when probable is said not of an isolated claim, but in relation with a world vision, S. Analogical thinking
Verisimilar is connected to the depiction arts through its second meaning, “depicting realism” (MW). It is typically said of a literary fiction or a pictorial style.

A witness is said to be credible as a person and as a narrator; she is a storyteller, depicting a situation. To be understood and credible this speech must necessarily conform to the linguistic laws of narrative: this is the point where probable and plausible, verisimilar connect.

From the point of view of its content, a story, an assertion, a representation of a state of affairs… is plausible if it is judged to be in conformity with common sense, with reasonable thinking. From the point of view of its structure, a conclusion is plausible if it is in conformity with the laws of the discursive genre stereotyping real things or events of the same kind.
The liar must comply with such rules of plausibility. The judgment of verisimilitude is refuted under the strategic precept « the true is not always truthful”:

It is not likely that the enemy would attack through the marshes
It is not likely that a mother would kill her children (Medea)
It is likely that one would kill out of jealousy; jealousy is a likely motive.

Pragmatic argumentation by positive consequences is based on plausibility, like a realistic novel; It can be considered, to the letter, as developping a causal fiction. Plausibility is assessed not so much by examining the case after an investigation of the reality of the facts, as by the intuitive conformity to certain conventions of narration and stereotypes of facts.
The concrete investigation that leads to a justified belief that things went like this can be difficult and inconclusive The intuition of normality is sufficient to conclude that they probably went that other way.
These definitions capture the linguistic foundation of the concept of probable as plausible, credible, creditable, verisimilar, truthful … as investigated in rhetoric.

Everyday arguments deal with language-made truth, which strives to be and to appear true, period. S. Persuasion

1.3 The probable-believable as an instrument of manipulation

The distinction between the probable-presumptive and the probable-verisimilar corresponds to the rhetorical distinction between two types of evidence, rhetorical evidence (so-called “technical” evidence) and non-rhetorical evidence (non-technical) evidence.
The investigation of the realities of the case is the business of specialists in other, non-rhetorical, fields. Rhetorical plausibility ignores the so-called “non-technical” evidence, which alone allows reality to inform the discourse.
Rhetorical plausibility is constructed through “proofs” derived from endoxa, that is, common beliefs. This method defines the specialized field of rhetoric, S. Doxa; Common place.
On such a basis, one can construct a very plausible representation of events, perfectly possible, but having absolutely nothing to do with what really happened. The implication is « it is possible – therefore it is ».

In other arenas, the struggle is much more indecisive. The construction of a possible world where plausible events take place is a matter of fictional coherence. The worlds of conspiracy and manipulation are worlds of this kind. The possible is thus considered as a generator of an « alternative reality » as real and more convincing because much more exciting than the other, for some.
This will to live in the fictional world allows to bypass the investigation or to refute it. The opinion on reality takes precedence over reality. The imagined world can keep the material world in check, at least for a while.

During the « Night of the Long Knives » (June 30, 1934) and the following days, the Nazi SS massacred the Nazi SA supporters of Röhm, the SA leader, himself a victim of the massacre, plus a number of Catholic or conservative opponents of Hitler’s regime. The left-wing opponents were already eliminated.
The explanation given by Hitler for these massacres was the existence of a plot by the SA against Hitler. It is indeed possible for a clique close to power to plot against the men in power belonging to that same clique; history is full of famous examples, and Piso’s conspiracy against Nero can serve as a model. The explanation is perfectly convincing. But historians have shown that Röhm never plotted against Hitler. The story was a typical manipulative lie.
But can we say that the rhetoric of the convincing imposed the passage from the possible to the true, thus proving its persuasive power? The explanatory fiction was accepted not only because it was after all possible, and therefore plausible, but because it was imposed in the public space by the propaganda and violence of the Nazi militias at work during those crucial weeks, the public enthusiasm manifesting the support of some and hiding the terror of others.

2. Truth and the predicate “— is true”

The predicates “— is true” and “— is false” apply to a statement or to the corresponding judgment, i.e., to the logical proposition expressing its content. Truth is “the adequacy between the thing and the intelligence” (Thomas Aquinas, Summa, Part. 1, Quest. 16, Art. 1), which may be interpreted as, “adequacy between the thing and its representation”.

According to Tarski’s famous definition of truth, “‘the snow is white’ is true if and only if the snow is white” (Tarski [1935]). Note that the proposition “snow is white” comes from Aristotle (Top., 11, 105a), who considers it as a prototypical statement not deserving a dialectical discussion because clearly true, so impossible to problematize, S. Dialectic; Conditions of discussion.
For Tarski, the concept of truth can be strictly defined in formal language only; “with respect to [colloquial language] not only does the definition of truth seem to be impossible, but even the consistent use of this concept in conformity with the laws of logic” [1935], p. 153).

We shall admit that ordinary language about human affairs can use some local, practical and satisfactorily defined concept of truth. “— is true” or “— is false” are said of a statement referring to an event or a state of things through a description that constitutes the meaning of the statement; this meaning is a linguistic construct, based on the common understanding that the statement must be relevant to the current discussion and action (Sperber & Wilson, 1995). Ordinary language is not transparent; the true statement is dependent not only on reality, but also on the linguistic system that generates it, and on the social constraints of relevance met by the speech it is part of.

Beyond the linguistic conditioning of its expression, disputability is a characteristic of the statements “this is true, you are right”, “this is wrong, you are wrong, you lie”. Truth is then a synthetic positive property attached to argumentation as such. Truth judgments oscillate between the argumentative pole of justification, and the pole of perceptual or intellectual self-evidence.

Argumentation is sometimes criticized for its alleged unsuitability for the expression and transmission of truth. A distinction must be made here between knowledge-related arguments and practical arguments. In the case of the former, the argument serves to reduce the uncertainty surrounding a claim. In the latter case, the argument seeks to develop a line of action from true or possible facts, combined with a set of values ​​and preferences.

From the point of view of argument in dialogue, truth is a provisional property attributed to a statement that has survived critical examination, conducted, under appropriate method in given  circumstances, within interested and competent groups, on the basis of data the quality and completeness of which have been assessed. As a construction, a truth judgment can be adjusted if more and better information becomes available, or if the critical method improves, S. Default.

3. The Platonic dramatization:
essential truth against manipulative social persuasion

In argumentative rhetoric, the question of the likely appears under two opposing views, either as an arbitrary social representation accepted in lieu of an absent truth, or as an approach to truth.

In Plato’s Phaedrus, Socrates defines rhetoric as “a way of directing the soul”:

Socrates: Well, then, isn’t the rhetorical art, taken as a whole, a way of directing the soul by means of speech, not only in the law courts and on other public occasions, but also in private? Isn’t it one and the same art whether its subject is great or small, and no more to be held in esteem — if it is followed correctly — when its questions are serious or when they are trivial? Or what have you heard about all this? (Plato, Phaedrus, 261a; CW p. 537)

This psychagogy (“art of guiding the soul”, probably deprived of its religious function of evoking the souls of the dead, but not of its magical connotations, immediately expresses the control function attributed to rhetorical persuasion, “the need for souls”, which motivates religious proselytism.

Socrates dramatizes the problem of truth by radicalizing the opposition of the plausible-persuasive to the true:

Socrates: […] No one in a law court, you see, cares at all about the truth of such matters. They only care about what is convincing. This is called “the likely”, and that is what a man who intends to speak according to art should concentrate on. (Id., 261a; CW p. 549)

And the proper way of conducting souls is postponed until we know the truth about the essence of all things:

Socrates: First, you must know the truth concerning everything you are speaking or writing about; you must learn how to define each thing in itself; and, having defined it, you must know how to divide it into kinds until you reach something indivisible. Second, you must understand the nature of the soul, along the same lines; you must determine which kind of speech is appropriate to each kind of soul, prepare and arrange your speech accordingly, and offer a complex and elaborate speech to a complex soul and a simple speech to a simple one. Then, and only then, will you be able to use speech artfully, to the extent that its nature allows it to be used that way, either in order to teach or in order to persuade. This is the whole point of the argument we have been making. (Id., 277b-c; CW p. 554)

The likely is “like” the true. But to say that a representation, a story is likely, or similar to what truly is or was, we must know what truly is or was. The position of Socrates is strong, since it is based on the impossibility to saying in any sensible way “A looks like B”, “Peter looks like Paul” when you do not know neither B, nor Paul.

When one has found the truth, one can speak truthfully and live in truth. The rhetoric adapted to this situation will no longer be a rhetoric of persuasion but a pedagogy of truth. According to Perelman & Olbrechts-Tyteca,

when Plato dreams, in his Phaedrus, of a rhetoric which would be worthy of the philosopher, what he recommends is a technique capable of convincing the gods themselves (Plato, Phaedrus, 273c)”. ([1958], p. 7).

In Phaedrus, the issue is not so much about convincing the gods as it is about diverting the sensible man from other fellow ordinary men:

And no one can acquire these abilities without great effort — a sensible man will make a laborious effort not in order to speak and act among human beings, but so as to be able to speak and act in a way that pleases the god as much as possible. (Plato, Phaedrus, 273e; C. W. p. 550)

Socrates has thus imposed the pathos of inaccessible truth, implying that rhetorical discourse is constructed on the basis of the likely, of verisimilitude, that is, on a pseudo-representation making it possible to forgo truth. Essentially, the function of persuasion is attached to argumentative rhetoric rather as a stigma marking its congenital incapacity to attain and even to approach the Truth, the Being and the Gods. The probable bears no relation to the true. To live in persuasion is to live in the world of belief and opinion, in the “cave” and not in the light of the truth. This apparently ineradicable view of rhetorical argumentation is rooted in the anti-democratic and antisocial criticism that Socrates addresses to the institutional, political and judicial discourses trying to handle the problems of the City.

4. The Aristotelian de-dramatization:
The probable oriented towards the true

The Socratic quest for truth unfolds in this atmosphere of tragic radicality. Aristotle radically de-dramatizes the whole problematic by arguing that elaborated probable opinion and truth do not conflict but are in fact complementary. This is the case for at least four reasons. On the one hand, a first range of three reasons:

(1) The true and the approximately true are apprehended by the same faculty; it may also be noted that (2) men have a sufficient natural instinct for what is true, and (3) usually do arrive at the truth. Hence the man who makes a good guess at truth is likely to make a good guess at probabilities (Aristotle, Rhet., 1355a 14-15; RR, p. 101; my numbering);

Fourth, manipulative rhetoric does not work, “things that are true and things that are just have a natural tendency to prevail over their opposites” (id., 1355a20; p. 101) — a wonderfully optimistic claim; finally, to top it off, it is possible to establish an ethical control on speech: “for we must not make people believe what is bad” (id., 1355a30; p. 101).

The plausible is thus defined not as any opinion bearing the mask of truth, but as a positive orientation, a first step towards truth, expressed in the form of an endoxon, that must be dialectically tested, S. Dialectic. It follows that “persuasion” is simply defined as a provisional state of the individual in his quest of truth, a first step toward a progressively constructed truth in progress.