oration, explain to me now the topic of questions, which you reserved
for the last of the three.

_C. P._ There are, as I said at the beginning, two kinds of questions:
one of which, that which is limited to times and persons, I call the
cause; the other, which is infinite, and bounded neither by times nor
by persons, I call the proposition. But consultation is, as it were, a
part of the cause and controversy. For in the definite there is what
is infinite, and nevertheless everything is referred to it. Wherefore,
let us first speak of the proposition; of which there are two kinds:
one of investigation; the end of this science, as for instance,
whether the senses are to be depended upon; the other of action, which
has reference to doing something: as if any one were to inquire by
what services one ought to cultivate friendship. Again, of the former,
namely, of investigation, there are three kinds: whether a thing is,
or is not; what it is; of what sort it is. Whether it is or not, as
whether right is a thing existing by nature or by custom. But what
a thing is, as whether that is right which is advantageous to the
greater number. And again, what sort of a thing anything is, as
whether to live justly is useful or not.

But of action there are two kinds. One having reference to pursuing
or avoiding anything; as for instance, by what means you can acquire
glory, or how envy may be avoided. The other, which is referred to
some advantage or expediency; as how the republic ought to be managed,
or how a man ought to live in poverty.

But again in investigation, when the question is whether a thing is,
or is not, or has been, or is likely to be. One kind of question is,
whether anything can be effected; as when the question is whether any
one can be perfectly wise. Another question is, how each thing can
be effected; as for instance, by what means virtue is engendered, by
nature, or reason, or use. And of this kind are all those questions
in which, as in obscure subjects or those which turn on natural
philosophy, the causes and principles of things are explained.

XIX. But of that kind in which the question is what that is which is
the subject of discussion, there are two sorts; in the one of which
one must discuss whether one thing is the same as another, or
different from it; as whether pertinacity is the same as perseverance.
But in the other one must give a description and representation as it
were of some genus; as for