Book 1
1.8
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.
1.9
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.
