Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
For just as all kinds of produce are not provided by every country, and as you will not succeed in finding a particular bird or beast, if you are ignorant of the localities where it has its usual haunts or birthplace, as even the various kinds of fish flourish in different surroundings, some preferring a smooth and others a rocky bottom, and are found on different shores and in divers regions (you will for instance never catch a sturgeon or wrasse in Italian waters), so not every kind of argument can be derived from every circumstance, and consequently our search requires discrimination.
Otherwise we shall fall into serious error, and after wasting our labour through lack of method we shall fail to discover the argument which we desire, unless assisted by some happy chance. But if we know the circumstances which give rise to each kind of argument, we shall easily see, when we come to a particular
place,what arguments it contains.
Firstly, then, arguments may be drawn from persons; for, as I have already said, [*](v. viii. 4.) all arguments fall into two classes, those concerned with things and those concerned with persons, since causes, time, place, occasion, instruments, means and the like are
Such are birth, for persons are generally regarded as having some resemblance to their parents and ancestors, a resemblance which sometimes leads to their living disgracefully or honourably, as the case may be; then there is nationality, for races have their own character, and the same action is not probable in the case of a barbarian, a Roman and a Greek;