But as regards the practice of rhetoric, it is not merely the case that the trained speaker will get the better of the untrained. For even the trained man will prove inferior to one who has received a better training. If this were not so, there would not be so many rhetorical rules, nor would so many great men have come forward to teach them. The truth of this must be acknowledged by everyone, but more especially by us, since we concede the possession of oratory to none save the good man. i.e. since our ideals are so high.

Some arts, however, are based on examination, that is to say on the knowledge and proper appreciation of things, as for instance astronomy, which demands no action, but is content to understand the subject of its study: such arts are called theoretical. Others again are concerned with action: this is their end, which is realised in action, so that, the action once performed, nothing more remains to do: these arts we style practical, and dancing will provide us with an example.

Thirdly there are others which consist in producing a certain result and achieve their purpose in the completion of a visible task: such we style productive, and painting may be quoted as an illustration. In view of these facts we must come to the conclusion that, in the main, rhetoric is concerned with action; for in action it accomplishes that which it is its duty to do.