ine works; first of all, the word
itself, and its whole order and ornaments; then the airy flights and
songs of birds; then the sound and heat of that same air; and the
numerous prodigies of divers kinds seen on the earth; and also, the
power of foreseeing the future by means of the entrails of victims:
many things, too, which are shown to the living by those who are
asleep: from all which topics the testimonies of the gods are at times
adduced so as to create belief.

In the case of a man, the opinion of his virtue is of the greatest
weight. For opinion goes to this extent, that those men have virtue,
not only who do really possess it, but those also who appear to
possess it. Therefore, those men whom they see endowed with genius
and diligence and learning, and whose life they see is consistent and
approved of, like Cato and Laelius, and Scipio, and many others, they
consider such men as they themselves would wish to be. And not only
do they think them such who enjoy honours conferred on them by the
people, and who busy themselves with affairs of state, but also those
who are orators, and philosophers, and poets, and historians; from
whose sayings and writings authority is often sought for to establish
belief.

XXI. Having thus explained all the topics serviceable for arguing, the
first thing to be understood is, that there is no discussion whatever
to which some topic or other is not applicable; and on the other hand,
that it is not every topic which is applicable to every discussion;
but that different topics are suited to different subjects.

There are two kinds of inquiry: one, infinite; the other, definite.
The definite one is that which the Greeks call [Greek: hupothesis],
and we, a cause; the infinite one, that which they call [Greek:
thesis], and which we may properly term a proposition.

A cause is determined by certain persons, places, times, actions, and
things, either all or most of them; but a proposition is declared in
some one of those things, or in several of them, and those not the
most important: therefore, a proposition is a part of a cause. But the
whole inquiry is about some particular one of those things in which
causes are contained; whether it be one, or many, or sometimes all.
But of inquiries, concerning whatever thing they are, there two kinds;
one theoretical, the other practical. Theoretical inquiries are those
of which the proposed aim is science; as, 'If it is inquired whether
right