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, 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.