The "Art" of Rhetoric (1.1.1-1.1.5)

Now, the majority of people do this either at random or with a familiarity arising from habit. But since both these ways are possible, it is clear that matters can be reduced to a system, for it is possible to examine the reason why some attain their end by familiarity and others by chance; and such an examination all would at once admit to be the function of an art.[*]

Now, previous compilers of Arts[*] of Rhetoric have provided us with only a small portion of this art, for proofs are the only things in it that come within the province of art; everything else is merely an accessory. And yet they say nothing about enthymemes which are the body of proof, but chiefly devote their attention to matters outside the subject;

for the arousing of prejudice, compassion, anger, and similar emotions has no connection with the matter in hand, but is directed only to the dicast.[*] The result would be that, if all trials were now carried on as they are in some States,

For all men either think that all the laws ought so to prescribe,[*] or in fact carry out the principle and forbid speaking outside the subject, as in the court of Areopagus, and in this they are right. For it is wrong to warp the dicast's feelings, to arouse him to anger, jealousy or compassion, which would be like making the rule crooked which one intended to use.