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.

Beings are categorized, named and defined on the basis of their shared characteristics (what bring them together?), and their specificities (what differentiate them from beings of another nature?).
A classification is a set of definitions organized according to their degree of generality, increasing (down-top) or decreasing (top-down).

Categorization and the organization of categories into classifications characterizes what Lévi-Strauss calls “the science of the concrete”, a fundamental science shared by all humans (1962], chap. 1), and the basis of ordinary argumentation.

From the point of view of argumentation, the system “categorization – definition – classification – syllogism” defines logic as an “art of thinking” in natural language. Until the development of mathematics with their application to experimental sciences and the emergence of formal logic, the theory of definition and classification served as an introduction to logical reasoning, that is, to scientific reasoning.

1. Fundamental predicates and essentialist definition

Fundamental predicates are also called « fundamental categories ». The theory of categories comes from Aristotle’s Categories and Topics, where he assigns to science the task of giving correct definitions of beings, i.e. definitions allowing them to be grouped in well-made classifications. Reconstructed by Porphyry (c.234 – c.305, in the Isagoge (« Introduction to the Categories of Aristotle »), and transmitted in the Middle Ages mainly by Boethius (c.480-525), this « Aristotelian methodology of definition » (de Pater, 1965) constituted the fundamental intellectual equipment of science until the modern age.[1]

Aristotle distinguishes five fundamental types of predicates (predicables, categories): genus, species, difference, proper, accident. The exact logico-metaphysical status of these notions is disputed, but their function is clear, it is to assign a logical-semantic structure to statements like the following ones

Suzan is a human.
Humans are animals
Humans are rational.
The horse neighs (meaning: horses neigh)
The (this) horse suffers.

The analysis in terms of categories assigns the following structures to these assertions:

— “Suzan is a human” predicates the species, “man”, of the individual, Suzan.
— “Humans are animals” predicates a genus, “animal” of a species, “man”.
— “Humans are rational” predicates a difference, “rational” of a species, “man”. Human and horse are two species belonging to the same genus animal; unlike the horse and other animals, man is endowed with reason, which is the defining difference between man and other animals.
— “Horses neigh”: in its generic interpretation, this statement attaches to the species “horse”, a property, “— neighs”. The property is a non-essential characteristic of a species; that is (all) horses neigh, and only horses neigh. The definition of man as a “featherless biped” is extensionally valid; on this basis, one can tell a human from any other being. Essentialist philosophy reproaches such definitions based on properties for saying nothing of what is, in essence, a human being.
— “This horse suffers” predicates an accident upon an individual. The accident belongs only to individuals, not to species or genus. The horse cannot be characterized, at any level, as “a suffering animal”; a particular horse can suffer or not, depending on the circumstances, it cannot, however, be a mammal or not.

The famous Aristotelian definition of man, that is human being, is built on this basis:

[ Humans_specie ] _definiendum ARE [reasonable_difference animals_genus] _definiens

The definition of a being by its species, its specific difference and its genus makes it possible to position it correctly in the classification to which it belongs.
An object is known when it has been successfully defined and classified. Then, it is associated with identical objects (in the same genus), and disassociated from individual that are closest to them, that is, individuals belonging to the same genus but to different species. This knowledge is not attached to it as a particular individual; this is what is meant by the expression “there is no science of the contingent”.

A wrong analysis of the kind of predication is at the origin of definition mistakes, leading to a wrong categorization. Suppose that the statement “some clouds are grey” and “all sparrows are grey” are true. This color is an accidental property of clouds, whereas it is a common characteristic shared by all sparrows, but not exclusively: elephants are also grey. The property, “being grey”, although shared by clouds, sparrows and elephants, does not allow them to be classified within the same natural genus. At most, we can say that, in term of their color, indeed, some clouds are like sparrows, S. Intra-Categorical Analogy; Metaphor.

2. Classifications of natural kinds

This “classificatory thinking” gives impressive results in the classification of natural entities. Every entity is classified at its proper level, in a global, comprehensive hierarchy, on the basis of its common and specific properties. At the very top of this great pyramid of classification, are the plant, animal and mineral kingdoms. Such a kingdom includes a number of orders; an order includes families; a family includes several genera; and a genus includes several species characterizing individuals. producing the following pattern of nested succession:

Kingdom => Order => Family => Genus => Species :: {Individuals}

The above series of categories constitute a seven-level taxonomy. Depending on the complexity of the kingdom considered, other intermediary levels must be introduced, for example: Kingdom => Division => Class => Order, etc.

A species is a set of individuals. It is the basic unit of taxonomy. In the animal kingdom, the individuals which make up a species come from the same, or similar, parents, and they can interbreed [2].

As a knowledge domain, a taxonomy requires a well-made denominative language, which is transparent for the specialist. Latin names are used to that end. The fairy ring mushroom (Fr. mousseron), for example, is known scientifically as Marasmius Oreades. This name corresponds to the following taxonomy: Genus: marasmius; Family: marasmiaceae; Order: Agaricales; Species: Oreades.

3. Syllogistic reasoning on natural taxonomies

Scientific classifications obey the laws of set theory.

Definitions are organized in taxonomies according to their generality. The tree-structure of the system of categories allows for valid syllogistic inferences. A taxonomic space defines a syllogistic space. This coupling between classification and syllogism is a fundamental instrument of ordinary argumentation; Reasoning means here moving in a controlled manner from one branch to the other in a “Porphyrian tree”.

A well-constructed taxonomy relies on definitions and authorizes inferences based on the nature of things: “— is a Labrador” implies “— is a dog”, and both also imply “—is a mammal” S. Definitions and Argument. Hence the syllogism:

Labradors are dogs, dogs are mammals, SO Labradors are mammals

From the definition humans_definiendum are [reasonable_difference animals_genus]_definiens
one can construct the valid syllogism:

Conversely, if the genus C includes the species E1, E2, … En, then we immediately infer the truth of the disjunction:

“to be a C” implies “to be either a E1, or a E2 or … or a En”
“X is a mammal” means “X is either a human, or a rat, … or a whale”.

Other implications are based on the fact that the genus is characterized by a set of properties that belong to all the species included within its scope. If “being a mammal” is defined as “being a vertebrate, warm-blooded, having a constant temperature, with pulmonary respiration, nursing the cubs” then all of these properties can be attributed to every mammal, regardless of their differences, that is, regardless of the species they belong to.

3. Ordinary classifications and natural reasoning

According to psychological and linguistic theories of the prototype, common classifications have three levels:

Beings are identified and designated primarily by the name of their “basic” category, characterized by its frequency or its perceptual, cognitive or cultural salience. Non-specialists first identify an animal as a dog, not as a mammal or a labrador.

The concepts of hyponym and hypernym are used in semantics to refer to pairs of terms in a hierarchic relationship. The hyponym relationship corresponds to the genus to species relation “rose is a hyponym of flower, all roses are flowers”. The hypernym relationship corresponds to the species to genus relation, “flower is hypernym of rose, some flowers are roses”.

Scientific categorization determines the exact position of an individual or of a class of entities in a taxonomy, where the terms have been given an essentialist definition from which it is possible to argue syllogistically.
Linguistic nomination-categorization assigns to an individual its current name and the definition associated with that name. This operation could be considered to be the basic argumentative technique, fundamental for all types of argumentation. The simple and stable system of scientific-Aristotelian categories is replaced by the infinitely complex system of meaning relationships in a given language.
Syllogistic reasoning remains possible on the islands of stability corresponding to semantic agreements, i.e. hyponyms/hypernyms hierarchies.

Since linguistic categories can be destabilized and revised, a pari arguments and arguments from the opposites play a predominant role in ordinary speech, especially in argumentative situations.
Socio-linguistic categories are said to be fuzzy and poorly defined; they are actually evolving categories, in a process of permanent de-stabilization and re-stabilization under the pressure of historical evolution of things, language change, and conversational necessities. They are debatable and adjustable; a pari argument and argument from the opposites play a predominant role in ordinary speech, especially in argumentative situations.

4. A non-Aristotelian “classification”

The following passage by Jorge Luis Borges refers to itself as a « classification », (h). It reveals the requirements of the Aristotelian classification by proper characters and specific differences; the interest of a theory of definition; and above all the renunciation of free association and subjectivity.

These ambiguities, redundancies, and deficiencies recall those attributed by Dr. Franz Kuhn to a certain Chinese Encyclopaedia called the Heavenly Emporium (*) of Benevolent Knowledge. In its distant pages it is written that animals are divided into: (a) belonging to the Emperor, (b) embalmed, (c) tame, (d) suckling pigs, (e) sirens, (f) fabulous, (g) stray dogs, (h) included in the present classification, (i) frenzied, (j) innumerable, (k) drawn with a very fine camelhair brush, (l) et cetera, (m) having just broken a water pitcher, (n) that from a long way off look like flies.
(*) Warehouse
Jorge Luis Borges, ‘The Analytical Language of John Wilkins’ [3].

Needless to say, this presentation has little to do with the reality of the classification methods actually used in ancient or contemporary China.

[1] In this book, the word category is used only in the sense defined in the entry Categorization – nomination, and not with the Aristotelian sense of « predicate, predicable or fundamental category ».

[2] From Jacques Brosse, Lexicon, in Atlas des arbustes, arbrisseaux et lianes, de France et d’Europe occidentale, Paris, Bordas, 1983 [Atlas of shrubs, bushes and lianas of France and Western Europe].

[3] Jorge Luis Borges. El idioma analÍtico de John Wilkins. In La Nación. 8 February 1942.
Translated and republished by Eliot Weinberger as “John Wilkins’ Analytical Language,” p. 229–232 in Jorge Luis Borges.The Total Library: Non-fiction, 1922–1986, Penguin, London, 1999.

Ad orationem, Lat. oratio, “speech, discourse”
Ad litteram, Lat. littera, “letter; writing”
Both labels can refer to written or oral speech

1. In law

In law, the appeal to the letter of the law is based on the strict meaning of its wording. It is countered by appealing to the spirit of the law, corresponding to the intention of the legislator.

2. In everyday argument

In everyday conversation, the label to the letter (ad litteram) refers to a second speech turn  based upon what has been expressly (“verbally”) said, word for word, by the other party, leaving aside what was meant by the first speaker. This is the case of indirect speech acts of request, softened as a question

L1: – Can you pass me the salt?
L2: – Yes

But L2 does not pass the salt shaker to L1. L2 answered the letter , without taking into account the fact that L1 was not asking him about his ability to pass the salt shaker, but was asking him to pass the salt (to do something).

In an argumentative situation, the label ad litteram response is used to refer to a  response, that sticks strictly sticks « to the letter » of what was said by the opponent, without trying to « understand » what the latter wanted to say:

The police : — Just tell me so-and-so did it, and I release you
The suspect : — « So-and-so did it »

The suspect said to the letter what the police asked him to say in order to be released. He answered the letter, but he probably won’t be released. In more serious circumstances:

I don’t know what you meant, I just anwered what you said.

The suspect fulfils his turn of speech, and returns the floor to the accuser, who must rephrase what he wants to say.
The reply addresses the word and sentence meaning and not the speaker’s meaning, that is the spirit or intention of what the other party actually said.

Appealing to the letter — Based on a methodical and exclusive exercise of reason (ad judicium^@), the argument on the merits (ad rem^@, to the matter^@) deals substantially with the the case.  The argument to the letter evades the issue by dealing only with its formal aspects.

This strategy can be used as a disorientating move, serving a destructive strategy. It bypasses the significant content of the intervention by focusing on the letter of the speech. It can even turn the letter of the speech against the intention of the speaker.
This maneuver is opposed to a response that charitably considers the intention of the discourse and does not seek to take advantage of a bad formulation.

Example

— SITUATION: A dispute about the legal and ethical management of science funding
1) Research in domain B is conditioned by a statutory provision S prohibiting research likely to lead to Type U results.
2) A research group submits to institution I a research project in domain B. The research objectives are defined in the research proposal accompanying the funding application. The funding is granted.
2) This research produces a result X

— CLAIM: X result is a U-type result. R did Type U research, and I funded type U research. Both knowingly broke the statutory provision.

=> ISSUE:
Does the research U contravene the statutory provision prohibiting research leading to Type U results?

— ANSWER NO: Strict meaning, appeal to the letter of the relevant text.

NO. U emerged; it was something unexpected. As you can read, there is nothing about a Type U research in the terms of reference given to the researchers.  No research likely to produce Type U results is included in the terms of reference.
That kind of unexpected things regularly happens in scientific research.

— ANSWER YES: Intentional interpretation, S. Motives and good reasons

THEY DO. U did not “emerge”, it was intentionally produced.
(1) Our panel of top-level scientist says that a competent researcher can foresee that Type U results would follow from the objectives as defined in the specifications.
(2) The reference terms does not explicitly refer to U as an objective of the research in order to avoid the obvious legal and political consequences.
(3) But they describe work that matches the commonly accepted definition of U and meet the criteria for Type U research according to distinguished members of the relevant scientific community.

Conclusion: They had an hidden agenda. They actually did Type U research, whether they used that phrase or not. [2]

[1] This example is derived from  Glenn Kessler, “The repeated claim that Fauci lied to Congress about ‘gain-of-function’ research”. The Washington Post, Oct. 29, 2021.
https://www.washingtonpost.com/politics/2021/10/29/repeated-claim-that-fauci-lied-congress-about-gain-of-function-research/