Institutio Oratoria

Such in the main are the usual topics of proof as specified by teachers of rhetoric, but it is not sufficient to classify them generically in our instructions, since from each of them there arises an infinite number of arguments, while it is in the very nature of things impossible to deal with all their individual species. Those who have attempted to perform this latter task have exposed themselves in equal degree to two disadvantages, saying too much and yet failing to cover the whole ground.

Consequently the majority of students, finding themselves lost in an inextricable maze, have abandoned all individual effort, including even that which their own wits might have placed within their power, as though they were fettered by certain rigid laws, and keeping their eyes fixed upon their master have ceased to follow the guidance of nature.

But as it is not in itself sufficient to know that all proofs are drawn either from persons or things, because each of these groups is subdivided into a number of different heads so he who has learned that arguments must be drawn from antecedent, contemporary or subsequent facts will not be sufficiently instructed in the knowledge of the method of handling arguments to understand what arguments are to be drawn from the circumstances of each particular case;