Institutio Oratoria

Quintilian

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

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.343
and sometimes himself states things of which he has no actual knowledge.

Now one of these points, namely whether the judges have knowledge of what is being said to them, has nothing to do with the art of oratory. The other statement, that art is concerned with things that are known, does however require an answer. Rhetoric is the art of speaking well and the orator knows how to speak well.

But,
it is urged,
he does not know whether what he says is true.
Neither do they, who assert that all things derive their origin from fire or water or the four elements or indivisible atoms; nor they who calculate the distances of the stars or the size of the earth and sun. And yet all these call the subject which they teach an art. But if reason makes them seem not merely to hold opinions but, thanks to the cogency of the proofs adduced, to have actual knowledge, reason will do the same service to the orator.

But,
they say,
he does not know whether the cause which he has undertaken is true.
But not even a doctor can tell whether a patient who claims to be suffering from a headache, really is so suffering: but he will treat him on the assumption that his statement is true, and medicine will still be an art. Again what of the fact that rhetoric does not always aim at telling the truth, but always at stating what is probable? The answer is that the orator knows that what he states is no more than probable.