Institutio Oratoria

Quintilian

Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.

Being a Peripatetic he regards it as a science, not, like the Stoics, as a virtue, while in adding the words

likely to prove persuasie to the people
he inflicts a positive insult on oratory, in implying that it is not likely to persuade the learned. The same criticism will apply to all those who restrict oratory to political questions, for they exclude thereby a large number of the duties of an orator, as for example panegyric, the third department of oratory, which is entirely ignored.

Turning to those who regard rhetoric as an art, but not as a virtue, we find that Theodorus of Gadara is more cautious. For he says (I quote the words of his translators),

rhetoric is the art which discovers and judges and expresses, mith an elegance duly proportioned to the importance of all such elements of persuasion as may exist in any subject in the field of politics.

Similarly Cornelius Celsus defines the end of rhetoric as

v1-3 p.311
to speak persuasively on any doubtful subject within the field of politics. Similar definitions are given by others, such for instance as the following:—
rhetoric is the power of judging and holding forth on such political subjects as come before it with a certain persuasiveness, a certain action of the body and delivery of the words.