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.

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