BELIEFS OF THE AUDIENCE
Arguments ad auditorem, ex datis, ex concessis

1. Beliefs of the Audience

In general, the speaker bases his argument on values, facts and principles that are common, traditional, probable or true knowledge, generally known to the audience. He may introduce new ones, possibly after discussion with his interlocutors.

He must also adapt to his audience and, above all, avoid coming into conflict with them. However, their universes of belief do not necessarily overlap. He may hold (or reject) certain facts that his audience ignores or denies (or admits).
He can resolve this delicate situation by prudently basing his argument only on data explicitly or implicitly admitted or held to be true by the audience; he sticks to « what has been granted » by his interlocutor or audience (Chenique 1975, p. 322).
If knowledge of the character of the audience is so important for argumentative rhetoric, it is mainly because it provides the speaker with a large reservoir of ex datis premises, V. Ethos, §5.

Argument ex datis, ex concessis, ad auditorem.

In classical rhetoric, arguments ad auditorem, ex concessis, ex datis correspond to the arguments based on the beliefs of the audience.

Argument ad auditorem, from the Latin auditor, « he who listens », the audience. The term is used by Schopenhauer ([1864], p. 43).

The phrases ex concessis, ex datis. The preposition ex is followed by a noun in the ablative, indicating origin, « drawn from ».
In argument ex datis, datis is the plural ablative of datum, « that which is given » (id.).
In argument ex concessis, concessis is the plural ablative of concessus, (singular ablative concessu) – concessus: « concession, permission, consent; concessu omnium, unanimous consent (Gaffiot).
In our case, ex concessis rather refers to the explicit consent of the audience, and ex datis more generally covers the sense of ‘given’.

The Latin label « argument ex concessis » denotes two forms of argument.
1) A form of argument from authority, referring to the argument from consensus: consensus of participants, general consensus, consensus of nations, even universal consensus. This argument makes it possible to reject a new proposal or suggestion by pointing out to its author that there is (and has been for a long time) a consensus on the point in question (if you came to the meetings, you’d know, we have no time to lose…).
The consensus argument marginalizes the opponent and tends to exclude him or her from the group.

2) An argument that develops the beliefs of the audience. The speaker who develops conclusions based on beliefs accepted by the audience is arguing ex concessis. In this sense, the ex concessis argument corresponds to the ex datis argument (Chenique 1975, p. 322).

2. Is Appealing to the Audience’s Beliefs Manipulative?

In order to argue within his audience’s world of beliefs, the speaker must
1) omit facts (which he believes to be true) when the audience ignores them or believes them to be false;
2) accept facts (which he holds to be false) when the audience holds them to be true.

The question immediately arises as to his attitude to the facts he claims and the values he proclaims. Does he share them, or does he pretend to? The suspicion of lies and manipulation hangs over his entire discourse.

The ex datis argument can be tricky to handle, because it can lead to attributing to the speaker beliefs that he only wields ex datis. The risk is well known in the field of religious argumentation: an author who presents himself as orthodox and who has undertaken to refute heretics can conceal his agreement with the theses he opposes by claiming to treat them only ex datis.
This form of argumentation calls for two principled criticisms, one foundationist and the other deontological.
According to foundationist principles, a conclusion, in order to be valid, must be based on true premises, truths of absolute knowledge; but the premises of ex datis argumentation are based solely on beliefs. That’s why it’s called fallacious: it’s not that the argument is outwardly formatted for this audience, but the more fundamental fact that the argument is only valid for this audience. Insofar as it counsiders a specific audience and the circumstances of the speech, all rhetorical argumentation is contestable from a foundationist point of view. See Subjectivity.
From a deontological point of view, assertions that correspond to the beliefs of the audience are not necessarily endorsed and supported by the speaker himself. However, in accordance with the principle of cooperation, the bona fide audience normally attributes to the speaker the beliefs and information on which he is arguing. If the speaker is better informed than his listeners, e.g. if he knows that P is true (or false) but his listeners believe that P is false (or true), if he has reliable information of which his listeners are unaware, and if he limits himself to taking into account what his listeners believe, then to say that he is arguing ex datis, ex concessis, ad auditores, etc., is simply to say that he is lying and manipulating his listeners. V. Conditions of Discussion; Manipulation.

2.1 Small Arrangements with Truth: Banal Manipulation.

This manoeuvre can be found in trivial speech situations, as in this ex datis threat, which only applies to certain children:

Loc – Santa Claus is going to be very angry about your behavior!

The speaker addresses the child as if he, the speaker, believes in the existence of Santa Claus, but he himself does not. In practice, he’s reinforcing a superstition, which is reprehensible.

Let’s imagine a speaker who is not superstitious at all, but his interlocutor who refuses to do important things on Friday the 13th. If the important meeting scheduled for Friday the 13th complicates the speaker’s schedule, he can say to Y in a light tone:

Loc – We’ll postpone the meeting until the 20th so we don’t have to do anything on Friday the 13th.

The reason is still superstition, but the real motive remains hidden. Perhaps the speaker is simply planning a long weekend.

2.2 The trilogue can Hinder Manipulation

In complex situations, the triloge of Proponent, Opponent, Third party (arbiter(s), and/or an audience with the power to decide) limits the risk of first-degree, face-to-face, manipulation.
If the proponent lies or misrepresents the facts, it is the job of the opponent to straighten out the narrative proposed to the assembly,  giving it the best possible dose of truth.

Serious manipulation occurs when lies invest the sphere of power, political power, the power of money, the power of media and social media. Then nothing can guarantee that the truth will eventually prevail in the face of systematic background manipulation.

3. Ex datis and Ad Hominem

Like ad hominem argumentation, ex datis argumentation is based on the beliefs of the audience. Ad hominem argumentation uses these beliefs to show that they are contradictory, without commenting on their validity: « If you really mean what you’ve just said, then you’re contradicting yourself by refusing to support intervention in Syldavia!

Arguing about the audience’s beliefs uses them positively for confirmation purposes. In principle, these data cannot be questioned and the conclusions they allow us to draw are irrefutable by the partner in this discussion. On the basis of this data, the argument concludes positively: « Besides, you said so yourself!

Consider the question: « Should we intervene militarily in Syldavia? »

You admit that Syldavian troops are poorly trained, that they risk being overwhelmed by events, and that unrest in Syldavia could spread to neighboring countries. We agree that this expansion would threaten our security; and no one denies that we must intervene when our security is threatened. So, you agree with me. Come and join us, and join the ranks of those in favour of our presence in Syldavia. See Ad hominem.

This argumentative strategy has something to do with maieutics « the art of leading a person to the truth of his or her convictions », to the conclusion that he or she does not dare to formulate, or is unable to formulate because he or she has not mastered the art of combining statements in order to draw the necessary conclusions.

Ex Datis/Ex Principiis In Philosophy

Kant proposed a distinction between knowledge ex datis, based on experience, and knowledge ex principiis, deduced from first principles.
History is the prototype of ex datis knowledge, philosophy and mathematics the prototypes of ex principiis knowledge; ex datis knowledge is merely a compilation of data. Following the Kantian understanding, we might think that ex datis argumentation is based on empirical data, « on the substance, on the things themselves »; this interpretation would make ex datis a kind of equivalent of ad rem, but this is not the case. The use of ex datis in argumentation is different from its use in philosophy.