¶ 21. The third shining forth (irradiatio) is that by which the mind (mens) is enlightened (illustratur) to persuade or incline the soul (animum); this is done by rhetoric. Hence it is fitting that the orator provide for the civic good, where there can be danger because of the dissension of souls (animorum). And [the orator] proceeds according to three attributes and a threefold type of cause, namely, demonstrative, deliberative, and judicial. {Note: St. Bonaventure draws heavily here on Cicero, On the Subdivision of Oratory}
¶ 22. The demonstrative [concerns] a person, such as to praise or blame: therefore it is either praise with respect to the good of the soul (animae), which are three, namely, virtue, knowledge (scientia), [and] truth; or it is praise with respect to the body, namely, beauty, fortitude, etc; or [it is] of the goods of fortune, like wealth, ancestry, [and] nationality.
¶ 23. The deliberative concerns [something] to be done, and then one is persuaded [to act], if security, utility, [and] honesty is present; or one is persuaded not to act, if damage, danger, [or] dishonesty follow.
¶ 24. The judicial concerns a thing which has been done, which involves a decision, conjecture, or legitimate doubt. A juridical decision is: “Have you done this? I have not done it;” which others have called a contested case. A [juridical] conjecture [occurs] when someone is brought in to testify. A legitimate juridical doubt is a juridical indictment, when a fact is conceded; but [a person] defends oneself because [the person] is not guilty, or because one may have done it by order of the lord, or because [the person] should have done it.
¶ 25. But for one to be a powerful orator, it is necessary that one should have an introduction to capture the good will [of the audience] that is not too long, nor obscure, nor too exquisite; [then] that one should have a narrative that relates the facts; [then] that one should divide the work [into parts to put them in order]; in doing so, one should beware of a multitude of parts. Then [the orator] develops one’s position by reasoning (rationes); then one should refute the adversary and demonstrate his reasoning to be frivolous; [and] then [the orator] draws his [or her] conclusion. Again it is necessary that one should have inventiveness, organization, elocution, [reliable] memory, and [good] pronunciation.