An apagogic argument is a form of argument by the absurd, which argues that unreasonable interpretations of the law must be rejected:

The apagogic argument assumes that the legislator is reasonable and could not have admitted an interpretation of the law that would lead to illogical or unfair consequences. (Perelman 1979, p. 58)

It parallels the psychological argument, presupposing that the legislator is rational and benevolent, V. Absurd; Juridical arguments.

According to Alexy, the apagogic argument is one of the four types of arguments prevailing in law, the others being the arguments by analogy, a contrario (opposites) and a fortiori, (1989, quoted in Kloosterhuis 1995, p. 140).

The rhetoric of figures defines the antithesis as an opposition between two terms (words or phrases) of opposite meanings, entering into parallel syntactic constructions. The argument scheme of the opposites materializes discursively as an antithesis.

1. Antithesis as argumentative diptych

An argumentative situation emerges with the appearance of a point of confrontation ratified as such, a stasis. It develops into a diptych, characterized by the confrontation of two schematizations, that is to say two sets of descriptions, narrations and argumentations supporting two opposing conclusions. At this stage, the two discourses develop at cross-purposes, without explicitly taking this opposition into account, S. Stasis. This elementary argumentative situation corresponds to a discursive antithesis.

Such a confrontation might be taken up in a structured monologue juxtaposing the two sides of the issue. Such a monologic diptych features an “antiphony”, that is two voices putting forward incompatible arguments with respect to the same issue. This is typically seen when an individual having a vested interest in an issue engages in inner deliberation, and oscillates between two points of view, acting actually as a third party. This situation is elaborated as a dilemma whose anti-oriented horns are articulated by an and:

I admire your courage and I pity your youth.
Corneille, Le Cid 2, 2, verse 43. Quoted by Lausberg [1960], §796

When the speaker clearly identifies with one of the two voices, the balance of the two voices is broken in favor of one of the positions. The and dilemma transforms into a but opposition, overcoming the antithesis:

… but I pity your youth; so I won’t accept your challenge to duel.

2. Antithesis, figure and argument

The following argumentation is structured by the scheme of the opposite:

(D1) He is submissive to the privileged; I would not like to confront him in a weak position.

exactly as the self-argued description:

(D2) He is submissive to the privileged and powerful, and hard with the weak.

Whereas in (D1), the second member of the scheme “he must be hard with the weak”, remains implicit, (D2) corresponds to a complete expression of the topos. But the two discourses are based on the same mechanisms, the argumentation is “valid” or acceptable insofar as the portrait sounds “true”; both are “convincing”. Description and argument are rooted in the same figure or scheme.

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1. Terminology

Structural analogy connects two complex domains, each articulating an indefinite and unlimited number of objects and relationships between these objects. It combines intra-categorical analogy (a property of objects) with proportional analogy (a property of relations). One could also speak of formal analogy (the areas have the same shape) or borrow the mathematical term “isomorphism”, S. Intra-categorical analogy; Proportion.

The expression “physical analogy” refers to the relationship between two objects when one is a replica of the other. The concept covers different phenomena, such as the relationship between a model and its original, or the relationship between a prototype and the object to be manufactured. The reasoning based on the model or prototype is then applied to the original.

Structural analogy is involved in the two following situations.

(i) A, B, C … are similar ­— To establish if the complex objects or domains A, B, C are similar, one has to compare their components and the relations between them. The conclusion of this investigation will be a claim such as “A, B, C… are similar”; “A, B, are indeed similar, but C is something different”, etc.

One may ask if the 1929 Great depression, the Lost Decade of Japan during the 90s, and the Argentinian Crisis in 2001 share some significant characteristics. The whole purpose of the investigation may be to establish a typology of economic crisis, without — as far as possible — drawing on preconceived ideas of how politicians will use the conclusions of this investigation.

The areas are symmetrical from the viewpoint of the investigation, which does not favor one of the areas over the others, but only focuses on their relationships.

(ii) A is similar to B — A contrario, the importance of the previous situation appears when the series involves the 2008 crisis. Given the actuality of this last crisis, it will certainly be tempting to see if we can “learn lessons” from the previous crises and to apply them to the 2008 case, with the intention of making provisions for the current situation. If the proponent uses the analogy 1929 ~ 2008 to predict a third world war, her opponent can rebut the inference by showing that the domains are not similar, and that it is therefore impossible to rely on the first instance, in 1929, to make inferences about something about what will happen in 20** and after (see farther).

The difference in status between the two areas is expressed in different ways. In his analysis of the metaphor, Richards opposes Tenor and Vehicle (1936); Perelman & Olbrechts-Tyteca speak of Theme and Phore ([1958], p. 501). A simple way to name these domains may be comparing domain / compared domain; or, in view of the analysis of argument, Resource domain / Target domain.

The argument by analogy works on the asymmetry of the compared areas; that is why these two areas will be designated, when necessary by the letters of alphabets, R, as Resource field and Π (capital Greek letter “pi”),   the Problematic field, targeted by the investigation. The field R is the source or the Resource on which the arguer relies to make changes in the Targeted area Π, or to derive from R certain consequences about Π. In other words, the Resource field R is the argument domain and the Targeted field Π is the conclusion domain. The two fields are differentiated from epistemic, psychological, linguistic and argumentative perspectives.

— In epistemic terms, the Resource field is the best-known area; the Target field is the area under exploration.
— In psychological terms, intuition and values operating in the Resource field are put to work in the Target field.
— In linguistic terms, the Resource field is well covered by a stabilized, well-known and easily spoken language; the Target domain is not.
— In practical terms, we know what to do within the Resource field whereas in the Target domain, we do not.

2. Explicative analogy

In the well-known analogy proposed by Ernest Rutherford between the atom and the solar system, the Resource field is the solar system, the Target field is the atom:

the atom is like the solar system.

This is a didactic analogy, intended to provide a first intuitive understanding of the atomic structure, taking advantage of a (supposed) better understanding of the solar system. The asymmetry of the areas is obvious: the Resource field, the solar system, has been known and understood for a long time. The Targeted field, the atom, is new, poorly understood, inaccessible to direct perception, enigmatic.

The explanatory analogy retains some educational merits even when partial. A comparison is not identification, and two systems can be compared simply in order to identify the limits of the comparison, that is, the irreducible specificities of each field, cf. infra, §6.

The analogy has explanatory value in the following situation:

In the world Π, the proposition π is poorly understood. In a world R, there is no debate over r. Π is isomorphic to R (structural, systemic analogy). The position of π in Π is the same as that of r in R. So, the knowledge, images, obligations… attached to r are now transferred to π; π  is now slightly better understood; we know how to do with π.

The analogy relationship integrates the unknown on the basis of the known. As causal explanations, explanations by analogy break the insularity of the facts.

The analogy is an invitation to see and handle the Problem through the Resource. The Resource domain is considered to be a model of the Target domain. The relation of the domain under investigation to the Resource domain is treated like that of the domain of investigation to an abstract representation of this domain. Otto Neurath uses a maritime metaphorical analogy to explain his vision of epistemology:

There is no tabula rasa. We are like sailors at sea, who must rebuild their ship without ever bringing her to a dock to be disassembled and rebuilt it with better items. (Otto Neurath, [Protocol Statement],1932/3.[1])

The analogy can be translated word for word: “There is no ultimate foundation of knowledge from which we could, without any presuppositions, re-build the whole of our present knowledge.” This resource is extremely powerful; the image could also be applied to social life: “There is no ‘good explanation’ (meaning “good discussion of our disagreements”) that permits reconstructing a damaged relationship and re-start from scratch.”

3. Arguments based on structural analogy

In ordinary situations, analogy is used argumentatively, as in the following case:

— In the world Π, we are in a difficult situation; what should we do? Should we accept or reject perspective π?
— But we know for sure what happened in a world R.
— Fortunately, Π is isomorphic to R (structural, systemic analogy); if necessary we can argue for that.
— The position of π in Π is the same as that of r in R.
—So we can act, in world Π, on the basis of the knowledge, images, obligations… attached to r — That is to say, we can now decide about π.

This argumentative operation argues that “if the domains are analogous, so are their corresponding elements and the relations between them”, which may prove true or false under further investigation. The analogy gives us something to think about, but proves nothing; the conclusion projected upon Π may be false or ineffective.

4. From analogy to metaphor and back

A language is attached to the Resource domain. For example, ​​the human body is referred to in a language that may be incomplete and fairly incoherent, but commonly understood, the language of the flow of organic matter, of popular physiology, of good health and sickness, life and death. This language synthetizes and builds a common intuition of the body. Other unfamiliar areas are not equipped with such a dense, effective and functional language. The analogy projects the language of the Resource area, the human body, onto the Problematic field, the society. As a result, the target can be problematized in a familiar, non-controversial language; so that social convulsions can be discussed and a cure found. The analogy is an invitation to see the problem through the lens of the resource; full metaphorization enables us to forget the glasses.

The following apologue is based on the analogy “society is like a body”, as expressed in the metaphorical expression “social body”. Note the explicitness of the vocabulary of analogy in the final commenting section.

The senate decided, therefore, to send as their spokesman Menenius Agrippa, an eloquent man, who was also accepted by the plebs as being himself of plebeian origin. He was admitted into the camp, and it is reported that he simply told them the following fable in primitive and uncouth fashion. ‘In the days when all the parts of the human body were not as now agreeing together, but each member took its own course and spoke its own speech, the other members, indignant at seeing that everything acquired by their care and labour and ministry went to the belly, whilst it, undisturbed in the middle of them all, did nothing but enjoy the pleasures provided for it, entered into a conspiracy; the hands were not to bring food to the mouth, the mouth was not to accept it when offered, the teeth were not to masticate it. Whilst, in their resentment, they were anxious to coerce the belly by starving it, the members themselves wasted away, and the whole body was reduced to the last stage of exhaustion. Then it became evident that the belly rendered no idle service, and the nourishment it received was no greater than that which it bestowed by returning to all parts of the body this blood by which we live and are strong, equally distributed into the veins, after being matured by the digestion of the food.’ By using this comparison, and showing how the internal disaffection amongst the parts of the body resembled the animosity of the plebeians against the patricians, he succeeded in winning over his audience.
Titus Livius, The History of Rome, Vol. 1, Bk 2; between 27 and 9 BC.[2]

The resource does not necessarily preexist its use in an analogy. An analogy can create ex nihilo a self-evident resource, as in the following analogy, proposed by Heisenberg in 1955. The danger mentioned in the first line refers to the cold war era, and the resource term is “a ship built with such a large quantity of steel and iron that its compass, instead of pointing to the North is oriented towards the iron mass of the ship.” Note that, once again, there is no clear-cut frontier between structural analogy and metaphor. Heisenberg refers to the situation he imagines as a metaphor; and in the next line, he uses a construction expressing an analogy: “humanity is in the position of a captain…”.

Another metaphor might make such a danger even clearer. By the seemingly un­limited growth of its material power, humanity is might be compared to a captain whose ship has been built out of such a large quantity of steel and iron that its compass, rather than pointing to the North, orients towards the huge iron mass of the ship. Such a ship would get nowhere. It would be blown off course and led in circles.

But back to the situation of modern physics: we must admit that the danger exists only if the captain does not know that his compass no longer responds to the magnetic force of the earth. By the time he understands this, the danger is already halved. Because the captain who, not wishing to turn around, wants to achieve a known or unknown purpose, will find a way to steer the boat, either by using new modern compass that does not react to the iron mass of the boat, or by steering in relation to the stars as sailors once did. It is true that the visibility of stars does not depend on us, and perhaps today do we see them only rarely. Despite this, our awareness of the limits of our hope in progress supposes the desire not to go in circles, but to achieve a goal. Once recognized, this limit becomes the first fixed point which allows a new orientation.
Werner Heisenberg, [Nature in Contemporary Physics], [1955][3]

5. Structural analogy as an epistemological barrier

Analogy is fertile to stimulate discovery and invention, useful for teaching and popularizing knowledge. Yet it becomes an epistemological obstacle when the proposed explanation by analogy seems so clear and satisfying that it hinders further research:

For example, blood flow like water. Canalized water irrigates the ground, so blood should also irrigate the body. Aristotle was the first to assimilate the distribution of blood from the heart to the body with the irrigation of a garden by canals (De Partes Animalium, III, v, 668 a 13 et 34). Galen did not think otherwise. But to irrigate the soil, it is ultimately to get lost in the soil. And here is exactly the main obstacle to a proper understanding of blood circulation.
Georges Canguilhem, [The Knowledge of Life], 1951.[4]

The systematic rejection of analogy as an instrument for knowledge is grounded in such observations.

6. Refutation of structural analogies

6.1 Vain analogy

In an explanation, the explanation (explanans) must be clearer than the thing to explain (explanandum). Analogical explanation must also satisfy this condition, and if the resource area is even less well known than the area under investigation the analogy does not help in the understanding of things.

The analogy is also vain when used to impress the audience and display the grandstanding of the speaker as familiar with the Resource domain. Gödel’s theorem is used extensively for this purpose (Bouveresse [1999]).

6.2 False analogy

An argument by analogy can be rejected by showing that there are critical differences between the Resource domain and the Target domain, prohibiting the projection of the former upon the latter so that no lesson can be learned from the supposed Resource domain. In the following passage for example, it is argued that the comparison of the 2008 and 1929 crisis is marred by the facts that the present situation in Germany has nothing to do with its situation after 1918 and the coming years. Furthermore, it is argued that there is nothing similar to Hitler and Nazism in the European landscape in 2009:

Jean-François Mondot — Does the economic crisis weaken our civilization? We sometimes hear intellectuals and columnists making analogies with the 1929 crisis that led to World War II.

Pascal Boniface — We often make the mistake of thinking that history repeats itself, and so make very risky comparisons. Russia bangs his fist on the table, everybody immediately talks about the Cold War. An economic and financial crisis erupts on Wall Street, and immediately an analogy is drawn with 1929, the suggestion being that Hitler could come to power as a result of these difficulties. Yet the political circumstances are obviously very different, insofar as no great country is now humiliated as Germany was after 1918, leaving it wishing to take revenge. This comparison is easy to make, but it has no basis, neither strategic nor intellectual.
Pascal Boniface, [The clash of civilizations is not inevitable], 2009.[5]

6.3 Partial analogy

Partial analogy (“misanalogy” Shelley, 2002, 2004) is an analogy that has been criticized and recognized as limited. The two domains cannot be equated. Nonetheless, partial analogy still has a pedagogical use, as seen in the case of the analogy between the solar system and the atom (cf. supra §2):

A central body: the sun, the nucleus of the atom.
Peripheral elements: the planets, the electrons.
A central mass much larger than peripheral masses: the mass of the sun is larger than the planets; the mass of the core is larger than that of electrons. —etc.

Differences (analogy breaks):

The nature of the attraction: electrical for the atom, gravitational for the solar system.
There are identical atoms, each solar system is unique.
There may be several electrons in the same orbit, whereas there is only one planet in the same orbit. — etc.
The fact that the limits of analogy are precisely known prohibits any automatic transposition of the knowledge gained in one field into the other field.

6.4 Reversed analogy

A conclusion C1 has been established for a Target resource on the basis of an analogy drawn from the Resource domain R. The opponent argues that the same analogy drawn from the same domain R leads to another conclusion C2 about the same Target domain, that is incompatible with C1 (“disanalogy” Shelley, ibid.). These two contradictory conclusions prohibit the use of the Resource domain to argue in the Target domain.

This is particularly effective because the opponent concedes to playing on her adversary’s home ground. The opponent accepts and examines more closely the analogy advanced by the proponent, in order to neutralize his or her conclusions. This strategy is exploited in the refutation of argumentative metaphors.

Argument: ­­— This area lies at the heart of our discipline.
Refutation: — That’s true. But disciplines also need eyes to see clearly, legs to move in, hands to act, and even a brain to think.
Other refutation — That’s true, but the heart can very well keep beating preserved in a jar.

A supporter of hereditary monarchy speaks against universal suffrage:

Argument:— An elected president, that’s absurd, we do not elect the driver.
Rebuttal: — Nor are there natural born drivers.

Both sides enact the same metaphorical field. This form of rebuttal has the strength of an ad hominem refutation, based on the own beliefs of the speaker: “You are your own refuter”.

Counter-analogy — As with any argument, one can oppose an argumentation by analogy by putting forward a counter-argumentation (an argumentation whose conclusion is incompatible with the original conclusion). This counter-argumentation can be of any kind, including another argument by analogy, taken from another Resource domain; an analogy equilibrates another analogy:

Argument:   — The university is (like) a company, so …
Rebuttal:     — No, it is (like) a daycare, an abbey …

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[1] Otto Neurath, “Protokollsätze”. Erkenntnis 3 (1932/3), p. 206. Quoted in A. Beckermann “Zur Inkohärenz und Irrelevanz of Wissensbegriffs”. Zeitschrift für Philosophische Forschung 55, 2001. P. 585.
[2] Trans. by Rev. Canon Roberts; Ed. by Ernest Rhys. J. M. Dent & Sons, Ltd., London, 1905. Quoted from; http://mcadams.posc.mu.edu/txt/ah/Livy/Livy02.html. No pag. (11-08-2017)
[3] Quoted after Werner Heisenberg (1962) La Nature dans la Physique Contemporaine. Paris: Gallimard, 1962. P. 35-36.
[4] Quoted after Georges Canguilhem, La Connaissance de la Vie. Paris: Vrin, 1965. P. 26-27.
[5] Pascal Boniface, “Le clash des civilisations n’est pas inévitable”. Interview by J.-F. Mondot, Les Cahiers de Science et Vie, 2009. www.iris-france.org / Op-2009-03-04.php3] (09-20-2013)

Intra-categorical analogy draws on the relationship between individuals belonging to the same category. For a definition of the concept of category, the categorization process of individuals; the organization of categories in classifications and the corresponding forms of syllogistic reasoning, S. Categorization and Nomination.

1. From identity to intra-categorical analogy and circumstantial analogy

1.1 Individual identity

An individual is identical to itself (not similar nor resembling); it is not “more or less” identical to itself. This self-evidence establishes the principle of identity “A = A”.

1.2 Identity of indiscernibles

Two different individuals perfectly identical, for example products taken out of the same industrial production chain, are materially identical, that is perceptually indistinguishable. All that can be said of one can be said of the other; their descriptions coincide, they share all their properties, essential (categorical) or accidental.

Discernibility depends on the observer, the layman does not see any difference, and believes that “it’s all the same”, whereas the specialist will make crucial distinctions.

1.3 Intra-categorical analogy

Intra-categorical analogy is the relationship between the members of a category C. All members share, by definition, the characteristics defining the category. The phrase “another C” refers to another member of the same class C. Two beings belonging to the same category are identical for this category; a whale and a rat are identical from the point of view of the category “­— be a mammal”. This categorical identity is a partial identity, compatible with major differences; two beings of the same category are said to be analogous or similar. They are comparable in respect of their other non-categorical properties. Chicken eggs are all similar as eggs; an egg is identical to another egg; it is comparable to all other eggs in terms of freshness, size, color, etc. S. Comparison.

1.4 Circumstantial analogy

An individual a possessing the features (x, y, z, t), is similar to all individuals who have any of those features, whether it be an essential or accidental feature.

The descriptors of two objects define the point of view under which they are equivalent; two beings are similar if their descriptions overlap, contain a common part, which may or may not include all or some of their essential features. In other words, this common part generates a category, which may or may not make sense. One might speak of circumstantial analogy. Alice and a snake are identical from the standpoint of the category “— is a long-necked egg eater”, S. Definition.

2. Intra-categorical analogy as induction or deduction

Intra-categorical analogy can be reconstructed as an induction or a deduction:

2.1 As an induction

O is similar to P
P has the properties w, x, y, m
O has the properties w, x, y
So O probably has also property m.

From an overall judgment of analogy between two beings, based on the shared features w, x, y … we conclude that if one has the property m then the other most probably also possesses m. In other words, analogy is pushed towards identity.

2.2 As a deduction

O is similar to P
P has the property m
Conclusion: O probably has the property m.

O is similar to P. This means that they share a common set of features, and therefore belong to the category C defined by those features. In conclusion, as members of the same category C, O and P probably share other properties, among them m. This means that the predicate « — is like” is to be interpreted as a weaker form of « — is the same as”; analogy is seen as a weakened identity.

Deduction and induction are considered valid forms of reasoning. The purpose of the discussion about the possibility of reducing analogy to deduction or induction is to determine whether or not analogy is also valid as a form of reasoning. Reasoning by analogy is sometimes used to prove the existence of God, the ideological stakes of this issue are therefore high.

These formulations of the argument by analogy in the form of a dialectical syllogism are rather sterile because they do not emphasize the warranting operations, that contain all the interesting problems. The formulation of the conclusion not as a secure finding but as the product of a heuristic rule of thumb, however, is of great value. The conclusion should be written not as something “probable”, that is a kind of belief, but as a suggestion to do something:

It might be interesting to test P for property m.
It might be interesting to see whether O and P share other properties.

3. Arguments based on intra-categorical analogy

— Categories as a whole are structured according to their respective definition; two individuals belong to the same category if they have the same definition.

— Categories may be gradual, S. Rule of Justice.

— Categorical analogies may be restructured S. A pari; Definition (III). 

4. Refutation of categorical analogy

In one or other aspect, everything is like everything else, and analogies can be more or less “far-fetched”. Any rejected categorical analogy will be dubbed fallacious and denounced as a confusion, an amalgam (Doury 2003, 2006).

Intra-categorical analogy can be refuted by showing that the category created from those two beings is not based on essential features, but on some accidental property; in general, the generated class is deemed irrelevant. The nonsensical analogy “Chinese ~ Butterfly”, ironically discussed by Musil, illustrates the perils of circumstantial analogy, based on the arbitrary choice of a non-essential feature, here the “lemon yellow” color.

There are lemon yellow butterflies; there are also lemon yellow Chinese people. So, in a sense, butterflies can be defined as miniature winged Chinese people. Butterflies and Chinese people are symbolic of sensual pleasure. Here we can see for the first time a glimmer of a possible match, never considered before, between the great period of the moth fauna and Chinese civilization. The fact that butterflies have wings and not the Chinese people is only a superficial phenomenon. […] Butterflies did not invent powder: precisely because the Chinese have done it before them. The suicidal predilection for the lights of some nocturnal species is still an artifact of the past, which is difficult to explain in view of the daylight understanding of this morphological relationship between butterflies and China.
Robert Musil, [Spirit and Experience], [1921] [1]

The analogy relationship has difficulties with transitivity, S. Relation. Intra-categorical analogy is transitive: if A and B on the one hand, B and C on the other hand, are said to be similar because they possess the same essential features, A is thus similar to C. Circumstantial analogy is not transitive: nothing proves that if, on the one hand, the descriptions of A and B have common parts, and, on the other hand, the description of B and C have common parts, then the description of A and C will also have also common parts. Khallaf invokes a traditional analogy to criticize the concatenation of analogies:

A man is walking on the beach trying to find similar shells; once he finds a shell similar to the original, he throws away the original shell and goes on to find a seashell which resembles the second, and so on. When she has found the tenth shell, she should not be surprised to see that it is totally different from the first in the series. (Khallâf [1942], p. 89)

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[1] Quoted in Jacques Bouveresse, Prodiges et vertiges de l’analogie [Prodigies and Dizziness of Analogy]. Paris: Raisons d’Agir, 1999. P. 21-22.

 

From an anthropological perspective, analogy is a form of thought that posits that things, people and events are reflected in each other. For analogical thinking, knowing is deciphering similarities; analogy unveils a world of secret links underlying reality, and generates a “cosmic feeling where triumph order, symmetry, perfection”, a closed world (Gadoffre & al. 1980, p. 50); thus conceived, analogy is the foundation of gnosis. From the perspective of the history of ideas, this form of thinking culminated in the Renaissance, when our “sublunary » world was, by analogy, mapped with the heavenly spheres, and with the divine world more generally.

In one of its manifestations, the doctrine of analogical correspondences validates the following type of argument:

Data: This plant looks like such or such part of the human body.
Conclusion: This plant has a hidden virtue, effective to cure the ills that affect the corresponding part of the body.
Warrant: If the shape of a plant is like a body part, then it cures ailments affecting that body part.
Backing: This is a divine provision.

This form of analogical thinking postulates that plants have hidden medicinal properties. The plant bears a divine signature, that is, a representation of the human body part that it can heal. This signature or “analogical sympathy” is a motivated signifier, a similarity or “resemblance” of the given body part. God, in his benevolence, has imposed this signature on particular plants in order to make them of use to us. A plant resembling the eyes, therefore might cure eye irritation.

Since the skin of the quince is covered with small hairs, it bears the “signature” of the hair, and eating the quince can make your hair grow. In the wording of Oswald Crollius [1609]:

Data: ‘This downy hair growing around quinces […] represents hair in some way.” (id., p. 41)
Conclusion: “So, their decoction makes hair grow, which fell because of the pox or another similar illness.” (ibid.)
Warrant: the healing power of plants “can be recognized more easily by the signature or analogical and mutual sympathy with the members of the human body with these plants than by anything else.” (id., p. 8)
Backing: “God gave an interpreter to each plant so that its natural virtue (but hidden in its silence) can be recognized and discovered. This interpreter can be nothing else than an external signature, that is to say a resemblance of form and figure, true indications of the goodness, essence and perfection thereof.” (id., p. 23)
Oswald Crollius, [Treatise on Signatures, or the True and Living Anatomy of the Big and the Small World]; [1609][1]

From this doctrine derives a research program for “those who want to acquire the true and perfect science of medicine”, “they should devote all their efforts to the knowledge of signatures, hieroglyphs and characters” (id., p. 20). Training will enable them to recognize “at first glance, on the surface of the plants, what faculties they are endowed with” (id., p. 9).

The knowledge of the medicinal properties of plants is acquired by learning how to read and understand the “discourse of nature”, that is to say, by mastering the signs scattered around the world. Such an analogical reading of the world is opposed to empirical causal investigation, which consists of observation and experience, practicing dissection or prescribing a concoction to the patient and then finding out if he or she is better, dead, or neither better nor worse. Analogical knowledge is a specific mode of thought, constitutive of magical thinking that substitutes for causal knowledge mysterious correspondences conveying influences, and bypasses the hierarchical system of categories organized according to genus and species, for which it substitutes a similarity network.

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[1] Quoted after Oswald Crollius, Traicté des Signatures ou Vraye et Vive Anatomie du Grand et Petit Monde. Milan: Archè, 1976.

• • Ambiguity (N), ambiguous (Adj) come from the Latin verb ambigere, “to discuss, to be in controversy”: qui ambigunt ‘those engaged in a discussion’ (Cic. Fin. 2,4)” (Gaffiot, Ambigo). To refer to the issue, the point upon which the partners disagree, Cicero uses the expression “illud ipsum de quo ambiguebatur”, “precisely that – about which – [they] dissent” (ibid.). Ambiguitas means “doubt”; the answers given by the Oracles were ambiguous in this sense.
    The word amphiboly is sometimes used in the discussion of the Aristotelian fallacies of ambiguity. It adapts a Greek word [amphibology] composed of amphi “on both sides”; bolos “throwing on all sides”; logos, “word”, and means “having a double meaning, equivocal”. Literally, an amphiboly is an “explosion of meaning”.

The word ambiguity may be used to refer to three fallacies “dependent on language”, homonymy, amphiboly, accent. These fallacies are defined as violations of the rule of syllogism or of dialectical reasoning, which require that language be univocal, S. Dialectic; Fallacies (2): Aristotle foundational list.

Issues of ambiguity arise at the word level (homonymy, accent), at the sentence level (syntactic ambiguity), or at the level of discourse. Such issues combine with the fact that non-ambiguous sentences may have several layers of signification, S. Presupposition; Words as Arguments.

1. Syntactic ambiguity

Sentence ambiguity, discussed by Aristotle from the perspective of a grammar of argumentation, is now seen as a syntactical issue. The famous Chomskyan ambiguous statement “flying planes can be dangerous” can be paraphrased as:

In some circumstances, flying planes is a dangerous activity
Planes are dangerous when they are flying.

These paraphrases are non-equivalent. The no less famous statement “the teacher says the principal is an ass” is syntactically ambiguous, it admits of two syntactic structures whose difference is marked by intonation or punctuation:

“The teacher”, says the principal, “is an ass”
The teacher says: “The principal is an ass”.

Ambiguity is sometimes a de-contextualization artifact, produced for the sake of grammatical or logical theory. In practice, the addition of a sufficient amount of left and right context suffices to clarify the intended meaning, as shown by the re-contextualization of the sentence “we saw her duck” (Wikipedia, Ambiguity), which is four times ambiguous when decontextualized:

we saw her duck swimming in the pool
we saw her duck to pick up something on the floor
we have no knife, so we saw her duck
she is a smart bridge player, we saw her duck

Serious ambiguity occurs when context does not disambiguate the sentence. The reduction of ambiguity to univocity is no less important for the interpretation of texts, sacred and others, than it is for logic, S. Interpretation. In De Doctrina Christiana, St Augustine specifies a rule to be applied when trying to interpret religious texts:

But when proper words make Scripture ambiguous, we must see in the first place that there is nothing wrong in our punctuation or pronunciation. Accordingly, if, when attention is given to the passage, it shall appear to be uncertain in what way it ought to be punctuated or pronounced, let the reader consult the rule of faith which he has gathered from the plainer passages of Scripture, and from the authority of the Church.
Augustine, [397] On Christian Doctrine, in Four Books, (our emphasis)[1]

The interpretive rule in the emphasized passage appeals to the consistency of the field of theological argument. It applies to the interpretation of the first verse of the first chapter of the St John Gospel. The issue is nothing less than the very concept of God. It must be shown that the correct “punctuation”, that is the correct reading of this verse, coincides with the orthodox conception of the Trinity, which affirms the divine identity and equality of the Father, the Son and the Holy Spirit. The reading which attributes a syntax of coordination to the utterance results in denying the identity of the Word, that is the Holy Spirit, with God; so, is must be considered heretical and rejected as such.

Now look at some examples. The heretical [punctuation], “In principio erat verbum, et verbum erat apud Deum, et Deus erat” “(In the beginning was the Word, and the Word was with God, and God was”); so as to make the next sentence run, “Verbum hoc erat in principio apud Deum” (“This word was in the beginning with God”), arises out of unwillingness to confess that the Word was God. But this must be rejected by the rule of faith, which, in reference to the equality of the Trinity, directs us to say: “et Deus erat verbum” (“and the Word was God”); and then to add: “hoc erat in principio apud Deum” (“the same was in the beginning with God”). (Id., Chap. II, 3)

It thus follows that, for Augustin, the orthodox punctuation and construction of the verse is:

In principio erat verbum, et Verbum erat apud Deum, et Deus erat Verbum. (Biblia Sacra…Parisiis, Letouzey et Ané, 1887).

This is a case of argumentative interpretation. The starting point is a sentence taken from the sacred text:

et verbum erat apud Deum et Deus erat
the Word was with God₁ and God₂ was

First reading, God₂ resumes (is co-referential with) God₁. This is a mere case of repetition, a kind of stylistic anaphora.

the Word was with God₁ and [God₁] was.

The following argued interpretation might be developed from this reading:

(i) Data: (1) B does exist — (2) A is with B.
(ii) Semantic rule:   if A is with B, then A is not B; that is,A and B are two different entities.
(iii) So, conclusion, by instantiation of the rule, The Word is not God.

To sum up, God exists, and He is unique (not Trinitarian). According to Augustine, this first interpretation is heretic.

Second reading, God₂ is co-referential with the Word:

the Word { [ was with God ] and [ was God ] }

Now, the Logos is God. This is the basis of the orthodox concept of the Trinity. The first reading is deemed fallacious, that is to say heretical. The alleged semantic rule (iii) is disposed of in the name of the mysterious nature of the Trinitarian link.

An interpretation is based upon a reading of the text; when necessary, this reading must itself be based upon a grammatical argument, the conclusion of which may or may not be decisive. Disambiguation is the founding operation for the vast and important domain of interpretive argumentation.

2. Word ambiguity: Homonymy, polysemy

Two words are homonymous when they have the same signifier (same spelling (homographs), same pronunciation (homophones) or both of these, yet have entirely different meanings. Homonymous words are listed as different entries in the dictionary:

Mine: “that which belongs to me.” (MW, Mine)
Mine: “a pit or excavation in the earth from which mineral substances are taken” (ibid.).

Polysemous words are semantic particularizations or acceptations of the same signifier within the same grammatical category. In the dictionary, they are listed under the same entry, and correspond to the first subdivision of meaning:

Mine, noun
1 a: a pit or excavation in the earth from which mineral substances are taken. b: an ore deposit.
2: a subterranean passage under an enemy position.
3: an encased explosive that is placed in the ground or in water and set to explode when disturbed.
4: a rich source of supply (id.)

When two different lines of derived words stem from the same root word, this word is in a process of splitting into two homonyms; this is the case of the three series derived from the word argument, S. To Argue, Argument.

2.1 Paralogism and sophism of homonymy

A syllogism is fallacious by homonymy when it articulates not three but four terms, one of the terms being taken in two different senses, S. Paralogism.

In the Euthydemus, Plato provides an example of sophisticated practice using a very special kind of homonymy. Euthydemus the sophist, the eponymous character of this dialogue, asks Clinias “who are the men who learn, the wise or the ignorant?” (Euth., 275d; p. 712). Poor Clinias blushes and answers that “the wise [are] the learners”; and six turns of speech later, he must agree that “it is the ignorant who learns” (Euth., 276a – b; p. 713). The young Clinias is quite stunned, and Euthydemus’ followers “broke into applause and laughter” (ibid.). Such sophisms are not intended to deceive their victims, but to destabilize their naive certainties about the language. By this salutary shock, the public becomes aware of the opacity and the proper form of language, S. Persuasion; Sophism. As Socrates later explains, “the same word is applied to opposite
 sorts of men, to both the man who knows and the man who does not” (id., 278a, p. 715).

Generally, the subject and object of a verb cannot be permuted; the situation where “A loves B” is different from the situation where “B loves A”. As to learn, to be the host of, to rent present this property:

to rent 1. pay someone for the use of (something, typically property, land, or a car). 2. (of an owner) allow someone to use (something) in return for payment.) (MW, Rent)

2.2 Homonymous and polysemous shifts

The plurivocity of words is blamed as a major source of confusion. Scientific language prohibits polysemy as well as homonymy, and calls for the use of univocal, well-defined terms stabilized in their meaning and syntax, in a given scientific field. Homonymy between a scientific term and a current word is harmless. In physics, the use of the word charm to refer to a particle, the charm quark creates no ambiguity.

In a reasoning using natural language, the meaning of terms is constructed and recomposed in the course of discourse, S. Object of discourse. The meaning of a word used by the same speaker may change from one stage of the argument to the following one. This results from a variety of mechanisms, such as the use of homonymous or closely similar words, or the use of a word in its literal and figurative senses in the same discourse. The discussion about the credit to be given to a person may, for example, subtly shift between setting the amount of a loan and trusting that person. In German, it seems that the economic discussion of financial debt remains linked to the discussion of moral fault, the same signifier, Schuld, having these two meanings. (Reverso, Schuld).

Homonymy and Polysemy may be re-adjusted by the operation of distinguo^@.

3. “Accent”: stress and paronomasia

In a language where word stress is linguistically relevant, shifting the stress from one syllable to another may change the meaning of the word, for example in Spanish (my underlining):

Hacía: stress on the second syllable, means “did”.
Hacia: stress on the first syllable, means “to”, preposition.

The words seem homonymous save for the accent (verbal and written), but are in reality two different words. Much like the fallacy of homonymy which shifts the meaning of a single signifier, the fallacy of accent also shifts the meaning of the word via a minimal but crucial supra-segmental change. This process occurs as though the difference between the signifiers is not considered salient enough to discriminate between the variations of meaning.

This is a special case of paronomasia (or annominatio), defined as a:

(Pseudo-) etymological play on the slightness of the phonetic change on the one hand and the interesting range of meaning which is created by means of the change on the other. The range of meaning can in such cases be raised to the level of paradox. (Lausberg [1960], §637)

Generally speaking, paronomasia creates a meaning generating cell, by contrasting or assimilating a word (signifier) W₀ with a minimally different word (signifier) W₁.

In dialogue, the paronomastic resumption of a term used by the opponent operates as a rectification, breaking the orientation of this discourse, S. Orientation Reversal, “this is not a crisis of conscience, this is a crisis of confidence”.

---

[1] Bk III, Chap. 2, 2. No pag. Quoted after https://www.ccel.org/ccel/augustine/doctrine.txt . (11-08-2017)

Agreements can be considered under four perspectives.

(1) In general, fully developed argumentative interactions are characterized by a preference for disagreement, which distinguishes them from consensual interactions, governed by a preference for agreement (Bilmes 1991), S. Politeness.

(2) The existence of “preliminary agreements” (Perelman, Olbrechts-Tyteca) in regard to both the organization of the discussion and the issues to be discussed, can be considered as a necessary condition for the fruitful conclusion of argumentation. In a dialectical exchange, previous specific agreements are imposed on the participants, as the rules of a game are imposed on the players. In a rhetorical address, the orator seeks a priori areas of agreement with the audience.
In civil life, argumentative encounters (courts, conciliation offices, parliaments, decisional meetings…) follow pre-established standard procedures upon which volens nolens, the participants must agree and comply with, whether they find them fair or not, S. Rules; Conditions of discussion.

(3) The production of an agreement can be regarded as the ideal purpose of argumentative interactions. In combination with (2), this makes argumentation a technique for transforming preliminary agreements into a final consensus. S. To persuade; Persuasion.

(4) The existence of a consensus can be exploited as an argument. In argumentations that justify a proposal by claiming that it is the subject of general consensus agreed on by everyone. The actual opponent to the claim appears therefore as an isolated eccentric individual, excluded from “our community”. His or her opinion is disqualified, and can be dismissed without taking the trouble to refute or even consider his or her arguments, S. Dismissal.

• • Lat. populus, “people”.

The label “populist speech” is both descriptive and evaluative. Such speech is stigmatized and is widely considered to be used to promote negative values, xenophobia and other irrational and brutal phobia; to call for action on the basis of non-controlled emotions and poor analysis as opposed to argued rational conclusions; and to make indiscriminate promises, suggesting that the proposed solutions are the only ones possible, easy to implement, that they will work miracles, and will have no negative consequences.

Populist discourse appeals to immediate satisfaction, and is opposed to the hardship discourse of perseverance and slow improvements: “If you vote for me, you will have to accept sacrifices. But, later, may be…”

“Populist” is the new label for ancient and modern “demagogues”, developing, for the sake of pure short-term electoral benefits, a discourse which they know is untenable.

1. Appealing to the beliefs of a group

The ad populum argument is sometimes defined as an argument derived from premises admitted by the audience, rather than from universal premises. Such an argument would therefore aim to achieve adherence rather than truth (Hamblin 1970, p. 41, Woods and Walton 1992, p. 211).

According to the Socratic criticism of assembly discourse as focusing on social persuasion when addressing the audience about their everyday affairs and worries, to the detriment of transcendental truth, all political speech would be inherently populist, S. Probable. In this sense, all rhetorical or dialectical arguments would be ad populum. The argument ad populum is then no different from the argumentation on the interests, beliefs and passions of the audience, abundantly referred to as ex concessis, ex datis, or ad auditores argument.

2. Appealing to emotion

“We can define the paralogism known as argumentum ad populum as an attempt to win the popular assent to a conclusion by arousing the emotion and enthusiasm of the masses” (Copi 1972, p. 29; quoted in Woods and Walton 1992, p. 213). The ad populum argument is negatively related to hatred and fanaticism, and not always positively to enthusiasm: it is caught in the general condemnation of passions, without taking into account the fact that on the one side, emotions may or may not be justified, and that, on the other side, good and bad arguments may be based on strong emotions, S. Emotion.

This definition corresponds to the designation ad captandum vulgus “playing to the gallery”, in other words, to theatrical oratory, not an exclusive characteristic of politicians. The orator becomes an actor. The criticism of ad populum joins the moral criticism of flattering discourse, and the critique of enthusiasm, conformism and group effects in general, as “bandwagon fallacies” and alignment with the majority crowd (ad numerum), S. Pathos; Emotions; Laughing; Consensus.

As in all cases of appeal to the passions, we might suspect substitution of the passions for the logos, hence a lack of relevance (Woods, Walton 1992, p. 215), S. Vicious circle..

3. Argumentative orientation of the word people

The word people can take two opposite argumentative orientations. The individualist, who believes that all virtue resides in the individual, may conclude, by application of the scheme of the opposite, that the crowd is inherently corrupt, and that all argumentation appealing to popular sentiment is therefore fallacious. The people are always the populace.

On the other hand, the adage vox populi vox dei, “the voice of the people, is the voice of God” gives the people a degree of infallibility. The popular corruption argument mirrors the ad superbiam fallacy, that is the accusation of pride (ad superbiam), a sin committed by people who consider themselves to be superior to an inherently corrupt people, S. Dismissal; Collections (2).

Boldly relying on an effect of composition backed by two analogies, Aristotle supports the superiority of the Many over the One:

According to our present practice assemblies meet, sit in judgment, deliberate, and decide, and their judgments all relate to individual cases. Now any member of the assembly, taken separately, is certainly inferior to the wise man. But the state is made up of many individuals. And as a feast to which all the guests contribute is better than a banquet furnished by a single man, so a multitude is a better judge of many things than any individual.

Again, the many are more incorruptible than the few; they are like the greater quantity of water, which is less easily corrupted than a little. The individual is liable to be overcome by anger or by some other passion, and then judgment is necessarily perverted; but it is hardly to be supposed that a great number of people would all get into a passion and go wrong at the same moment. (Aristotle, Politics, III, 15. Jowett, p. 99)

— Maybe “hardly to be supposed”, nonetheless historically well documented.

4. Populum and plebs: The people and the crowd

In republican Rome, the appeal to the people, provocatio ad populum, was a right of appeal (jus provocationis) in criminal trials, a basic human right of the defendant. As a last resort, an accused Roman citizen would be able to bring his case before the populus. The populus is the assembled people, constituted as a political-judicial body, in the comitia centuriata, the solemn assembly of the people, in which full citizens vote and make decisions. In these assemblies, the gods themselves speak via the voice of the people. The populus is therefore very distinct from the vulgus or the plebs as haphazard, unorganized wholes.

This right is linked to Republican institutions: “tradition claims that the provocatio ad populum was created by a law of the consul Publicola the same year the Republic was created” (Ellul [1961], 278). With the Empire, “the provocatio ad Cæsarem evicted the provocatio ad populum” (Foviaux 1986, p. 61), that is to say, that Caesar replaced the People.

• • Lat. incommodum, “inconvenience”.

Bossuet defines the argument ad incommodum as “the argument that brings about an inconvenience” ([1677], p. 131). This is a variant of the refutative use of the pragmatic argument, and can be considered as a kind of appeal to the absurd.

Bossuet illustrates this scheme via an example designed to prove the necessity of absolute political power and absolute religious power. He argues that the negation of these authoritarian postulates would have “pernicious” consequences, respectively “men would devour one another”, which is certainly not a desirable state, and “there would be as many religions as heads”, which is deemed undesirable by Bossuet:

If there were no political authority which one obeys without resistance, men would devour one another. And if there were no ecclesiastical authority to which individuals were obliged to submit their judgment, there would be as many religions as heads. Now, it is false that men should devour one another, and that there be as many religions as heads. Therefore, we must necessarily admit a political authority to which we obey without resistance, and an ecclesiastical authority to which individuals submit their judgment. ([1677], p. 131)

• • Lat. homo, “human being”.

1. Ad hominem as personal attack, ad personam

Today, ad hominem is commonly used to mean ad personam, but classical ad hominem argument is quite distinct from personal attack (or ad personam attack), which seeks to disqualify the person in order to get rid of the arguments.

2. Ad hominem as self-contradiction or inconsistency

The concept of the ad hominem strategy is to be found in Aristotle’s Rhetoric, topic n° 22:

Another line of argument is to refute your opponent’s case by noting any contrast or contradiction of dates, acts or words that it anywhere displays. (1400a15; RR p. 373).

Under that name, the ad hominem argument is defined by Locke as a discussion technique by which the speaker “[presses] a man with consequences drawn from his own principles or concessions. This is already known under the name of argumentum ad hominem”. ([1690], p. 411)

The term “principle” can be taken in the moral or intellectual sense of “first principles”. In both cases, the speaker rearticulates the system of beliefs and values ​​of the opponent, in order to identify a contradiction. Locke rejects this form of argument as fallacious, insofar as it is based on the specific belief structure of a person, without relevance for the discussion of the truth per se of the thesis under debate, “[it does not] follow that another man is in the right way, because he has shown me that I am in the wrong” (ibid.).

The ad hominem argument is of no force and plays no role as an alethic instrument, in the process of establishing truth, S. Collections (3):Modernity and tradition

In regard to this definition, Leibniz notes that:

The argument ad hominem has this effect, that it shows that one or the other assertion is false and that the opponent is deceived whatever way he takes it. ([1765], pp. 576-577)

He thus recognizes the merits of this form of argument in the context of a discussion, as an epistemic instrument, urging a reorganization of a system of knowledge.

Under Locke’s presentation, ad hominem argument bears on explicit propositions as put forward in a knowledge acquisition dialogue and is clearly deductive and propositional.

In general terms, ad hominem argumentation occurs in a dialogue when the speaker builds a discourse, referring not only to propositional beliefs but also to the behavior and actions of his or her opponent, in order to point out some contradiction. This has the effect of embarrassing the opponent and causing him or her to reconsider his or her speech, positions or actions.

Ad hominem argumentation typically results in the feeling of “embarrassment”, considered as a basic emotion by Ekman (1999, p. 55). The production of such an emotion is not an accidental by-product of ad hominem, but is built into it, as revealed by the verb “to press”, that is “to assail, harass; afflict, oppress”. “Embarrassment” is typically a cognitive-emotional feeling, as is the basic argumentative emotion, “doubt”. Nonetheless, ad hominem is not emotional in the same vein as personal abuse can be, S. Personal Attack.

3. Setting up the words against the words

We have a reply ad hominem in the following case:

Proponent: — P. I propose P

Opponent: — Before, you proposed entirely different things.

 

Issue: — Should the term of the presidential mandate, currently five years, be reduced to four years?

Proponent (former President): — I am for a reduction to four years.

Opponent: — But in an earlier statement, while you were president yourself, you yourself argued that five years were necessary for the proper functioning of our institutions. Please, clarify.

The quoted statement which opposes the present one may be drawned not only from what has been said by the opponent in the past, but also from what has been said by “his or her people”, that is to say, by members of the discursive community sharing the same argumentative orientations: people of the same party, religion, scientific trend, etc., that cannot be easily disavowed.

The ad hominem reply allows the speaker to intervene in a discourse in the third party’s mode, that is, without committing himself to the substance of the debate. He does not explicitly take on the role of an opponent, but speaks simply as a participant in good faith, seeking clarification.

In an accusatory context, the charge of narrative incoherence allows the accused to reject the accusatory narrative, S. Consistency.

Reactions to ad hominem refutation on what has been said before

The target of the ad hominem argument can choose to sacrifice the former position, to reject the contradiction, or to accept it.

(i) Sacrifice the former position:

— Circumstances have changed, we must follow our times.

— I have developed my system

— I have changed, only madmen never change their mind; do you prefer psychorigid people?

(ii) Use a direct rebuttal. The opponent elicits the contradiction: “you say both A and Z, which is inconsistent”; the force of this argument is derived from the quotation mechanism. The proponent did not necessarily say A or Z but something else, A’ or Z’, that the opponent paraphrases, rephrases or reinterprets as A or Z. The contradiction may therefore proceed from a reworking of the speech, S. Straw Man. It follows that the proponent can reply to the letter, and reject the key ad hominem phrase “you yourself admitted” in his or her second turn:

— You make me out to say what I have never said, you distort my words

In other cases, the precise relation between A and Z, that is, the nature and degree of the inconsistency, might be disputable, S. Denying; Opposites.

The ad hominem imputation can be directly dismissed on these two counts.

 (iii) Accept the contradiction. The ad hominem reply seeks an individual free from contradiction. By a classic maneuver in stasis theory, the recipient may choose to assume what he or she has been criticized for, thus making contradiction a system of thought, S. Stasis; Contradiction:

— I fully accept my inconsistencies. I love rain and good weather.

4. Setting up the beliefs of the speaker against their words

In the preceding case, there was direct opposition between a present claim and an earlier assertion. Consider the issue of the withdrawal of troops sent to intervene in Syldavia:

Q:    —Should we withdraw our forces from Syldavia?

S1:    — Yes!

Let us suppose however that S1 has been led to admit A, B, and C; or, at least that S2 speaks as if he sincerely believed that S1 supports these propositions:

S2: — But you said yourself that (A) the Syldavian troops are poorly trained, and (B) that the political unrest in Syldavia is likely to extend to the whole region, there is a real contagion risk. You will agree that such an extension would threaten our own security (C); and no one denies that we must intervene if our security is threatened. So you have to admit that we have to stay in Syldavia.

S1 therefore claims that P; S2 argues ex datis, that is, on the basis of beliefs held by S1 (or attributed to him), and concludes not-P. This is the case considered by Locke. Must S1 admit that he or she has made an error, and that we should not withdraw the troops? Obviously not; S2 simply showed by his objection that one cannot support both {A, B, C} and not-P.

Reactions to the ad hominem refutation on reconstructed beliefs

S1 can re-adjust and rearticulate all the key components of S2‘s discourse. He can argue that A, B, C are abusive reformulations of his beliefs, or that the full analysis of the Syldavian situation is much more complex than these three assertions.

If S1 accepts such a reconstruction of his speech and beliefs, then he or she must reform one or more of these propositions, rejecting for example the idea that the troubles in Syldavia can extend to the whole region. S1 is expected only to correct, clarify or explain more thoroughly why this system of beliefs {A, B, C} cannot be expanded into non-P. This is precisely the point the argument ad hominem is getting at. In this function, ad hominem replies are a powerful educational tool.

5. Setting up the prescriptions and practices of the speaker against their words

A contradiction can also be raised between, on the one hand, what I require from others, what I prescribe or forbid them, and, on the other hand, what I’m doing myself, the kind of example I set. There is some paradox in asking others not to smoke, while I smoke myself. In our culture, acts are considered “to speak louder than words”, and injunctions are systematically flouted if the speaker does not comply with them himself:

Doctor, heal thyself!

He’s not a good marriage counselor, he’s always arguing with his wife!

You claim to teach argumentation and you are unable to argue yourself!

You advocate for the rights of women and at home you never do the dishes.

Note that, in the last two arguments, the conjunction and coordinates two anti-oriented statements, and not, as is more commonly the case, two co-oriented statements, S. Orientation.

The ad hominem game can be played in several moves:

Question: Should hunting be prohibited?
S1:    — yes, hunters kill animals for pleasure!
S2:   — but you eat meat, don’t you?

L2‘s argumentation can be reconstructed as “We must prohibit, suppress hunting. Hunters kill for pleasure. That’s awful!”. The opponent constructs an ad hominem argument:

You say killing animals for pleasure is wrong. But you eat meat, which presupposes that animals are killed for you. You condemn the hunters and you support the butchers. There is a contradiction here.

In his follow up, S1 can retort that there is a decisive difference. The hunter kills for pleasure, the butcher by necessity; and S2 can refute this refutation by arguing that there is no need to eat meat, whereas it is quite necessary to have fun.

This last form of ad hominem corresponds to what Bossuet calls an a repugnantibus argument: “Your conduct does not suit your speech” ([1677], p.140).

The expression “circumstantial ad hominem” refers to cases in which the speaker the notices a contradiction between his or her opponent’s speech and his or her personal circumstances, material welfare, lifestyle or personal position. S. Circumstances.

Defense against such an accusation — The preacher of virtue, to whom one points out that his or her practices do not support his or her counsels, finds support in the Lockian analysis of ad hominem, declared inherently fallacious:

My personal circumstances have no bearing on the truth or moral validity of my preaching.

Such a person may add that he or she has a divided personality:

It is true, I am a sinner, but it is from the depths of darkness that one feels best the necessity of light

This is natural, the cobbler’s children go barefoot.

Nonetheless, this form of argumentation is feared by preachers, who are expected to preach preach not only by exempla but also by example.

The real impact of ad hominem argument is not on the truth of what is said, but on the right to say what is said. The next reply may be “What you say is probably true and right, but I do not want to hear it from you”, or “That’s true, but it’s not for you to say”.

6. Setting up facts against words

S. Irony

7. Argumentation upon the beliefs of the partner

Whereas ad hominem argument goes after possible inconsistencies in the discourse of the opponent, arguments built upon the beliefs of the opponent or of the audience are  a positive form of exploitation of the partner’s belief system, considered as a coherent whole, S. Ex datis; Ex concessis