Rhetoric is the counterpart of Dialectic. Both alike are concerned with
such things as come, more or less, within the general ken of all men and belong
to no definite science. Accordingly all men make use, more or less, of both;
for to a certain extent all men attempt to discuss statements and to maintain
them, to defend themselves and to attack others. Ordinary people do this either
at random or through practice and from acquired habit. Both ways being
possible, the subject can plainly be handled systematically, for it is possible
to inquire the reason why some speakers succeed through practice and others
spontaneously; and every one will at once agree that such an inquiry is the
function of an art.

Now, the framers of the current treatises on rhetoric have constructed but a
small portion of that art. The modes of persuasion are the only true
constituents of the art: everything else is merely accessory. These writers,
however, say nothing about enthymemes, which are the substance of rhetorical
persuasion, but deal mainly with non-essentials. The arousing of prejudice,
pity, anger, and similar emotions has nothing to do with the essential facts,
but is merely a personal appeal to the man who is judging the case.
Consequently if the rules for trials which are now laid down some states --
especially in well-governed states -- were applied everywhere, such people
would have nothing to say. All men, no doubt, think that the laws should
prescribe such rules, but some, as in the court of Areopagus, give practical
effect to their thoughts and forbid talk about non-essentials. This is sound
law and custom. It is not right to pervert the judge by moving him to anger or
envy or pity -- one might as well warp a carpenter's rule before using it.
Again, a litigant has clearly nothing to do but to show that the alleged fact
is so or is not so, that it has or has not happened. As to whether a thing is
important or unimportant, just or unjust, the judge must surely refuse to take
his instructions from the litigants: he must decide for himself all such points
as the law-giver has not already defined for him.

Now, it is of great moment that well-drawn laws should themselves define all
the points they possibly can and leave as few as may be to the decision of the
judges; and this for several reasons. First, to find one man, or a few men, who
are sensible persons and capable of legislating and administering
justice is easier than to find a large number. Next, laws are made after long
consideration, whereas decisions in the courts are given at short notice, which
makes it hard for those who try the case to satisfy the claims of justice and
expediency. The weightiest reason of all is that the decision of the lawgiver
is not particular but prospective and general, whereas members of the assembly
and the jury find it their duty to decide on definite cases brought before
them. They will often have allowed themselves to be so much influenced by
feelings of friendship or hatred or self-interest that they lose any clear
vision of the truth and have their judgement obscured by considerations of
personal pleasure or pain. In general, then, the judge should, we say, be
allowed to decide as few things as possible. But questions as to whether
something has happened or has not happened, will be or will not be, is or is
not, must of necessity be left to the judge, since the lawgiver cannot foresee
them. If this is so, it is evident that any one who lays down rules about other
matters, such as what must be the contents of the "introduction" or the
"narration" or any of the other divisions of a speech, is theorizing about
non-essentials as if they belonged to the art. The only question with which
these writers here deal is how to put the judge into a given frame of mind.
About the orator's proper modes of persuasion they have nothing to tell us;
nothing, that is, about how to gain skill in enthymemes.
