Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
I would have my younger readers realise that these words are penned for their special benefit that they may not desire to adopt a different style in their exercises from that in which they will be required to speak, and may not be hampered by having to unlearn what they have acquired. For the rest if they are ever summoned to take part in the counsels of their friends, or to speak their opinions in the senate, or advise the emperor on some point on which he
IX. I now come to the forensic kind of oratory, which presents the utmost variety, but whose duties are no more than two, the bringing and rebutting of charges. Most authorities divide the forensic speech into five parts: the exordium, the statement of facts, the proof, the refutation, and the peroration. To these some have added the partition into heads, proposition and digression, the two first of which form part of the proof.
For it is obviously necessary to propound what you are going to prove as well as to conclude. Why then, if proposition is a part of a speech, should not conclusion be also? Partition on the other hand is merely one aspect of arrangement, and arrangement is a part of rhetoric itself, and is equally distributed through every theme of oratory and their whole body, just as are invention and style.
Consequently we must regard partition not as one part of a whole speech, but as a part of each individual question that may be involved. For what question is there in which an orator cannot set forth the order in which he is going to make his points? And this of course is the function of partition. But how ridiculous it is to make each question an aspect of proof, but partition which is an aspect of a question a part of the whole speech.
As for digression (egressio, now more usually styled excessus ), if it lie outside the case, it cannot be part of it, while, if it lie within it, it is merely an accessory or ornament of that portion of the case from which digression is made. For if anything that lies within the case is to be called part of it, why not