Further, it is evident that the only business of the litigant is to prove that the fact in question is or is not so, that it has happened or not; whether it is important or unimportant, just or unjust, in all cases in which the legislator has not laid down a ruling, is a matter for the dicast himself to decide; it is not the business of the litigants to instruct him. First of all, therefore, it is proper that laws, properly enacted, should themselves define the issue of all cases as far as possible, and leave as little as possible to the discretion of the judges; in the first place, because it is easier to find one or a few men of good sense, capable of framing laws and pronouncing judgements, than a large number; secondly, legislation is the result of long consideration, whereas judgements are delivered on the spur of the moment, so that it is difficult for the judges properly to decide questions of justice or expediency. But what is most important of all is that the judgement of the legislator does not apply to a particular case, but is universal and applies to the future, whereas the member of the public assembly and the dicast have to decide present and definite issues, and in their case love, hate, or personal interest is often involved, so that they are no longer capable of discerning the truth adequately, their judgement being obscured by their own pleasure or pain.
 All other cases, as we have just said, should be left to the authority of the judge as seldom as possible, except where it is a question of a thing having happened or not, of its going to happen or not, of being or not being so; this must be left to the discretion of the judges, for it is impossible for the legislator to foresee such questions. 
 If this is so, it is obvious that all those who definitely lay down, for instance, what should be the contents of the exordium or the narrative, or of the other parts of the discourse, are bringing under the rules of art what is outside the subject; for the only thing to which their attention is devoted is how to put the judge into a certain frame of mind. They give no account of the artificial proofs, Systematic logical proofs (enthymeme, for example), including testimony as to character and appeals to the emotions (2.3), which the rhetorician has to invent ( εὑρεῖν , inventio ) for use in particular cases. They are contrasted with inartificial proofs, which have nothing to do with the rules of the art, but are already in existence, and only need to be made use of. The former are dealt with in chs. 4-14, the latter in ch. 15 of this book. which make a man a master of rhetorical argument.
 Hence, although the method of deliberative and forensic Rhetoric is the same, and although the pursuit of the former is nobler and more worthy of a statesman than that of the latter, which is limited to transactions between private citizens, they say nothing about the former, but without exception endeavor to bring forensic speaking under the rules of art. The reason of this is that in public speaking it is less worth while to talk of what is outside the subject, and that deliberative oratory lends itself to trickery less than forensic, because it is of more general interest. κοινότερον : or, more intelligible to the ordinary man. For in the assembly the judges decide upon their own affairs, so that the only thing necessary is to prove the truth of the statement of one who recommends a measure, but in the law courts this is not sufficient; there it is useful to win over the hearers, for the decision concerns other interests than those of the judges, who, having only themselves to consider and listening merely for their own pleasure, surrender to the pleaders but do not give a real decision. The case as a rule being a matter of personal indifference, the judges are likely to be led away by the arguments which seem most plausible. That is why, as I have said before, in many places the law prohibits speaking outside the subject in the law courts, whereas in the assembly the judges themselves take adequate precautions against this.