ition.
For if the question is, "Whether pertinacity and perseverance are the
same thing," it must be decided by definitions. And the topics which
are incidental to a discussion of this kind are those drawn from
consequents, or antecedents, or inconsistencies, with the addition
also of those two topics which are deduced from causes and effects.
For if such and such a thing is a consequence of this, but not a
consequence of that; or if such and such a thing is a necessary
antecedent to this, but not to that; or if it is inconsistent with
this, but not with that; or if one thing is the cause of this, and
another the cause of that; or if this is effected by one thing,
and that by another thing; from any one of these topics it may be
discovered whether the thing which is the subject of discussion is the
same thing or something else.

With respect to the third kind of inquiry, in which the question is
what the character of the matter in question is, those things are
incidental to the comparison which were enumerated just now under the
topic of comparison. But in that kind of inquiry where the question
is about what is to be sought for or avoided, those arguments are
employed which refer to advantages or disadvantages, whether affecting
the mind or body, or being external. And again, when the inquiry is
not what is honourable or discreditable, all our argument must be
addressed to the good or bad qualities of the mind.

But when right and wrong are being discussed, all the topics of equity
are collected. These are divided in a two-fold manner, as to whether
they are such by nature or owing to institutions. Nature has two
parts to perform, to defend itself, and to indicate right. But the
agreements which establish equity are of a threefold character: one
part is that which rests on laws; one depends on convenience; the
third is founded on and established by antiquity of custom. And again,
equity itself is said to be of a threefold nature: one division of it
having reference to the gods above; another, to the shades below; a
third, to mankind. The first is called piety; the second, sanctity;
the third, justice or equity.

XXIV. I have said enough about propositions. There are now a few
things which require to be said about causes. For they have many
things in common with propositions.

There are then three kinds of causes; having for their respective
objects, judgment, deliberation, and panegyric. And the object of each
po