Institutio Oratoria

Hermagoras, who asserts that its end is to speak persuasively, and others who express the same opinion, though in different words, and inform us that the end is to say everything which ought to be said with a view to persuasion, have been sufficiently answered above, when I proved that persuasion was not the privilege of the orator alone.

Various additions have been made to these definitions. For some hold that rhetoric is concerned with everything, while some restrict its activity to politics. The question as to which of these views is the nearer to the truth shall be discussed later in its appropriate place.

Aristotle seems to have implied that the sphere of the orator was all-inclusive when he defined rhetoric as the power to detect every element in any given subject which might conduce to persuasion; so too does Patrocles who omits the words in any given subject, but since he excludes nothing, shows that his view is identical. For he defines rhetoric as the power to discover whatever is persuasive in speech. These definitions like that quoted above include no more than the power of invention alone. Theodorus avoids this fault and holds that it is the power to discover and to utter forth in elegant language whatever is credible in every subject of oratory.