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 instance, what sort of a man a miser is, or what pride is.

But in the third kind, in which the question is what sort of thing something is, we must speak either of its honesty, or of its utility, or of its equity.  Of its honesty thus.  Whether it is honourable to encounter danger or unpopularity for a friend.  But of its expediency thus.  Whether it is expedient to occupy oneself in the conduct of state affairs.  But of its equity thus.  Whether it is just to prefer one’s friend to one’s relations.  And in the same kind of discussion, in which the question is what sort of thing something is, there arises another