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 difference between the epicheireme and the syllogism, except that the latter has a number of forms and infers truth from truth, whereas the epicheireme is frequently concerned with statements that are no more than credible. For if it were always possible to prove controversial points from admitted premises, the orator would have little to do in this connexion.