Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
nor would the pilot's art exist, because in sea-fights pilots may be found on different sides; nor yet could there be an art of generalship, since general is pitted against general. In the same way rhetoric does not undo its own work. For the orator does not refute his own arguments, nor does rhetoric even do so, because those who regard persuasion as its end, or the two good men whom chance has matched against one another seek merely for probabilities: and the fact that one thing is more credible than another, does not involve contradiction between the two.
There is no absolute antagonism between the probable and the more probable, just as there is none between that which is white and that which is whiter, or between that which is sweet and that which is sweeter. Nor does rhetoric ever teach that which ought not to be said, or that which is contrary to what ought to be said, but solely what ought to be said in each individual case.
But though the orator will as a rule maintain what is true, this will not always be the case: there are occasions when the public interest demands that he should defend what is untrue. The following objections are also put forward in the second book of Cicero's de Oratore: [*](II. vii. 30.) —
Art deals with things that are known. But the pleading of an orator is based entirely on opinion, not on knowledge, because he speaks to an audience who do not know,v1-3 p.343and sometimes himself states things of which he has no actual knowledge.