Institutio Oratoria

Quintilian

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

My second reason was that indications, if indubitable, are not arguments, since they leave no room for question, while arguments are only possible in controversial matters. If on the other hand they are doubtful, they are not arguments, but require arguments to support them.