1. The predicative rhetorical genre
The classical rhetorical genres, the deliberative, the judicial, the epidictic, all relate to civil life. Christian religious rhetoric has developed a new genre, preaching, where persuasion is put to the service of religious faith. Predication is the action name associated with the verb to preach, and the noun preacher. It has not been affected by the derogatory orientations sometimes associated with these two words in contemporary usage. It is homonymous with the word predication as used in grammar and logic to designate the operation by which a predicate (a verbal group) is associated with a subject in a sentence; and with the word to predicate something upon, that is to base an action or a saying upon:
I predicated my argument on the facts. (tfd, Predicate)
Preaching as an argumentative genre fully complies with the definition of argumentation provided by Perelman & Olbrechts-Tyteca as a discursive effort “to induce or to increase the mind’s adherence to the theses presented for its assent” (/1969, p. 4). The theses referred to in this case are religious beliefs, that are articles of faith from the point of view of the preacher. Assuming that the audience is composed of believers, by preaching to them, the pastor assures their ongoing training and increases their degree of belief, in other words, “the soul’s adherence” to their creed (after Perelman & Olbrechts-Tyteca, , p. 4).
If the audience is composed of unbelievers, the missionary might preach to them in order to instigate these same beliefs. If the audience is composed of heretics in a position of strength, rhetoric must give way to dialectic.
The tenants of the Catholic faith are given in the Holy Scriptures, and are commented on by the authorities, the Fathers of the Church. These contents are articulated and applied in sermons by means of various speech techniques, which have established themselves in a sometimes polemical tension between dialectical appeals to reason and rhetorical enthusiasm for faith, S. Faith.
2. The exemplum
The exemplum (plural exempla) is an instrument of preaching which has been particularly developed by the Dominican and Franciscan mendicant orders, from the beginning of the thirteenth century. Structurally, the exemplum is a narrative, exploiting the resources of the fable. The genus is legitimated by the very example of Christ who preached by parables. The exempla present models of action to be followed or avoided.
The exemplum is “a brief narrative given as truthful and intended to be inserted into a discourse (usually a sermon) to convince an audience by a salutary lesson” (Brémond & al. 1982, pp. 37-38). Brémond distinguishes metaphorical and metonymic exempla.
2.1 Metonymic exemplum
In such exempla, the fact is presented as being likely. There is then a certain identity of status between the heroes of the anecdote and the recipients of the exhortation. The parable of the evil rich is told to the rich, and the logicians are told the tale of one of their colleagues, who is tormented in hell for his sins, that is to say, his sophisms.
The following exemplum deals with the fate of souls after death, and especially with purgatory. The lesson it contains is a “Christian denunciation of vain pagan erudition” (Boureau, p. 94), and a call to the logicians to convert to a religious life.
For our edification, it may be useful to know that a harsh sentence is inflicted upon sinners at the end of their lives.
This is what happened in Paris, according to the Parisian Cantor (= Peter the Chanter, Petrus Cantor). Master Silo urged one of his colleagues, who was very ill, to come and visit him after his death and to inform him of his fate. The man appeared before him a few days later, wearing a cloak of parchment covered with sophistic inscriptions and full of flames. The master asked him who he was. He replied, “I am the one who promised you that he would visit.” When asked what his fate was, he said, “This cloak weighs me down and oppresses me more than a tower. They make me bear it for the vainglory which I have derived from the sophisms. The flames with which it is filled represent the delicious and varied furs I wore, and this flame tortures me and burns me”. And as the master found this slight penalty, the deceased told him to stretch out his hand to test the lightness of punishment. On his outstretched hand, the man dropped a bead of sweat, which drilled the hand of the master as fast as an arrow. The Master experienced an extraordinary agony, and the man said to him, “so it is with all my being”. Afraid of the harshness of this chastisement, the master decided to leave the world and enter religion. And in the morning, facing his gathered students, he composed these verses:
To the frogs, I give up croaking /To the ravens, cawing, / To the vain, vanity.
I attach my fate /To a logic that does not fear the conclusive ‘therefore’ of death.
And, abandoning the world, he took refuge in religion.
Jacobus da Varagine, The Golden Legend, written around 1260
The practice of exemplum goes beyond the strictly religious domain. Fontenelle’s “Golden Tooth” is actually a lay metonymic exemplum illustrating the fallacy of finding the cause of a fact that does not exist, S. Cause – Effect.
2.2 Metaphorical exemplum
In such exempla, “the narrative no longer quotes a sample of the rule, but a fact that resembles it” (ibid.):
The hedgehog, it is said, when he enters a garden, takes on a load of apples which he fixes on his prickles. When the gardener arrives, the hedgehog wants to run away, but his load prevents him doing so, and thus he is caught with his apples. […] This is what happens to the unfortunate sinner who is taken, when he dies, with the burden of his sins.
Humbert from Romans, [The Gift of Fear or the Abundance of the Examples], written between 1263 and 1277.
 Quoted after Jacques de Voragine, La Légende Dorée. Text presented by A. Boureau. In J.-C. Schmitt (ed.), Prêcher d’exemples [Preaching Exempla]. Paris: Stock, 1985. P. 7.
 Humbert from Romans, Le Don de Crainte ou l’Abondance des Exemples. Trans. from Lat. to French by Chr. Boyer. Lyon: PUL. 2003. P. 116.