Institutio Oratoria

Quintilian

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

As regards arguments, they may be found either in the questions raised by the case, which may be considered by themselves quite apart from any connexion with individual

v4-6 p.195

things or persons, or in the case itself, when anything is discovered in it which cannot be arrived at by the light of common reason, but is peculiar to the subject on which judgment has to be given. Further, all proofs fall into three classes, necessary, credible, and not impossible.

Again there are four forms of proof. First, we may argue that, because one thing is, another thing is not; as It is day and therefore not night. Secondly, we may argue that, because one thing is, another thing is; as The sun is risen, thereit is day. Thirdly, it may be argued that because one thing is not, another thing is; as It is not night, therefore it is day. Finally, it may be argued that, because one thing is not, another thing is not; as He is not a reasoning being, therefore he is not a man. These general remarks will suffice by way of introduction and I will now proceed to details.