Institutio Oratoria

Quintilian

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

For proof and credibility are not merely the result of logical processes, but may equally be secured by inartificial arguments. Now I have already [*](v. ix. 2.) distinguished signs or, as he prefers to call them, indications from arguments. Consequently, since an argument is a process of reasoning

v4-6 p.209

which provides proof and enables one thing to be inferred from another and confirms facts which are uncertain by reference to facts which are certain, there must needs be something in every case which requires no proof.

Otherwise there will be nothing by which we can prove anything; there must be something which either is or is believed to be true, by means of which doubtful things may be rendered credible. We may regard as certainties, first, those things which we perceive by the senses, things for instance that we hear or see, such as signs or indications; secondly, those things about which there is general agreement, such as the existence of the gods or the duty of loving one's parents;