politics, and many other things that have nothing to do with one
another. Take, for instance, the line of argument concerned with
'the more or less'. On this line of argument it is equally easy to
base a syllogism or enthymeme about any of what nevertheless are
essentially disconnected subjects-right conduct, natural science, or
anything else whatever. But there are also those special Lines of
Argument which are based on such propositions as apply only to
particular groups or classes of things. Thus there are propositions
about natural science on which it is impossible to base any
enthymeme or syllogism about ethics, and other propositions about
ethics on which nothing can be based about natural science. The same
principle applies throughout. The general Lines of Argument have no
special subject-matter, and therefore will not increase our
understanding of any particular class of things. On the other hand,
the better the selection one makes of propositions suitable for
special Lines of Argument, the nearer one comes, unconsciously, to
setting up a science that is distinct from dialectic and rhetoric. One
may succeed in stating the required principles, but one's science will
be no longer dialectic or rhetoric, but the science to which the
principles thus discovered belong. Most enthymemes are in fact based
upon these particular or special Lines of Argument; comparatively
few on the common or general kind. As in the therefore, so in this
work, we must distinguish, in dealing with enthymemes, the special and
the general Lines of Argument on which they are to be founded. By
special Lines of Argument I mean the propositions peculiar to each
several class of things, by general those common to all classes alike.
We may begin with the special Lines of Argument. But, first of all,
let us classify rhetoric into its varieties. Having distinguished
these we may deal with them one by one, and try to discover the
elements of which each is composed, and the propositions each must
employ.

                                 3

  Rhetoric falls into three divisions, determined by the three classes
of listeners to speeches. For of the three elements in
speech-making--speaker, subject, and person addressed--it is the
last one, the hearer, that determines the speech's end and object. The
hearer must be either a judge, with a decision to make about things
past or future, or an observer. A member of the assembly decides about
future events, a juryman about past events: while those who merely
decide on the orator's skill are observers. From this it follows
that there are three divisions of oratory-(1) political, (2) forensic,
and (3) the ceremonial oratory of display.

  Political speaking urges us either to do or not to do something: one
of these two courses is always taken by private counsellors, as well
as by men who address public assemblies. Forensic speaking either
attacks or defends somebody: one or other of these two things must
always be done by the parties in a case. The ceremonial oratory of
display either praises or censures somebody. These three kinds of
rhetoric refer to three different kinds of time. The political
orator is concerned with the future: it is about things to be done
hereafter that he advises, for or against. The party in a case at
law is concerned with the past; one man accuses the other, and the
other defends himself, with reference to things already done. The
ceremonial orator is, properly speaking, concerned with the present,
since all men praise or blame in view of the state of things
existing at the time, though they often find it useful also to
recall the past and to make guesses at the future.

  Rhetoric has three distinct ends in view, one for each of its
three kinds. The political orator aims at establishing the
expediency or the harmfulness of a proposed course of action; if he
urges its acceptance, he does so on the ground that it will do good;
if he urges its rejection, he does so on the ground that it will do
harm; and all other points, such as whether the proposal is just or
unjust, honourable or dishonourable, he brings in as subsidiary and
relative to this main consideration. Parties in a law-case aim at
establishing the justice or injustice of some action, and they too
bring in all other points as subsidiary and relative to this one.
Those who praise or attack a man aim at proving him worthy of honour
or the reverse, and they too treat all other considerations with
reference to this one.

  That the three kinds of rhetoric do aim respectively at the three
ends we have mentioned is shown by the fact that speakers will
sometimes not try to establish anything else. Thus, the litigant
will sometimes not deny that a thing has happened or that he has
done harm. But that he is guilty of injustice he will never admit;
otherwise there would be no need of a trial. So too, political orators
often make any concession short of admitting that they are
recommending their hearers to take an inexpedient course or not to
take an expedient one. The question whether it is not unjust for a
city to enslave its innocent neighbours often does not trouble them at
all. In like manner those who praise or censure a man do not
consider whether his acts have been expedient or not, but often make
it a ground of actual praise that he has neglected his own interest to
do what was honourable. Thus, they praise Achilles because he
championed his fallen friend Patroclus, though he knew that this meant
death, and that otherwise he need not die: yet while to die thus was
the nobler thing for him to do, the expedient thing was to live on.

  It is evident from what has been said that it is these three
subjects, more than any others, about which the orator must be able to
have propositions at his command. Now the propositions of Rhetoric are
Complete Proofs, Probabilities, and Signs. Every kind of syllogism
is composed of propositions, and the enthymeme is a particular kind of
syllogism composed of the aforesaid propositions.