XXXII.  I think, then, that it belongs to a perfectly eloquent man, not only to have the ability, which is his peculiar province, of speaking copiously and with the assertion of large principles, but also to possess its neighbouring and contiguous science of dialectics:  although an oration appears one thing and a discussion another; nor is talking the same thing as speaking; though each belongs to discussing.  Let then the system of discussing and talking belong to the logicians; but let the province of the orators be to speak and to embellish their speeches.  Zeno, that great man, who founded the school of the Stoics, was in the habit of showing with his hand what was the difference between these arts; for when he had compressed his fingers and made a fist, he said that dialectics were like that; but when he had opened his fingers and expanded his hand, he said that eloquence was like his open palm.  And even before him Aristotle, in the beginning of his Rhetoric, said, that the art of eloquence in one portion of it corresponded to dialectics; so that they differ from one another in this, that the system of speaking is more wide, that of talking more contracted.  I wish, then, that this consummate orator should be acquainted with the entire system of talking, as far as it can be applied to speaking; and that (as indeed you, who have a thorough acquaintance with these arts, are well aware) has a twofold method of teaching.  For Aristotle himself has given many rules for arguing:  and those who followed him, and who are called dialecticians, have delivered many very difficult rules.  Therefore I think, that the man who is tempted by the glory of eloquence, is not utterly ignorant of those things; but that he has been brought up either in that old school, or in the school of Chrysippus.  Let him first acquaint himself with the meaning and nature and classes of words, both single and combined; then let him learn in how many ways each word is used; then how it is decided, whether a thing is false or true; then what results from each proposition; then to what argument each result is a consequence, and to what it is contrary; and, as many things are stated in an ambiguous manner, he must also learn how each of them ought to be distinguished and explained.  This is what must be acquired by an orator; for those things are constantly occurring; but, because they are in their own nature less attractive, it is desirable to employ some brilliancy of eloquence in explaining them.

XXXIII.  And since in all things which are taught in any regular method and system, it is first of all necessary to settle what each thing is, (unless it is agreed by those who are discussing the point, what the thing really is which is being discussed; nor otherwise is it possible to discuss anything properly, or ever to get to the end of the discussion,) we must often have recourse to words to explain our meaning about each thing; and we must facilitate the understanding of an involved and obscure matter by definition; since definition is a kind of speech which points out in the most concise possible manner what that is which is the subject of discussion.  Then, as you know, when the genus of each thing has been explained, we must consider what are the figures or divisions of that genus, so that our whole speech may be arranged with reference to them.