The Complete Aristotle (eng.)

act not to have been
committed if you were maintaining that.
    It should be noted that only where the question in dispute falls
under the first of these heads can it be true that one of the two
parties is necessarily a rogue. Here ignorance cannot be pleaded,
as it might if the dispute were whether the act was justified or
not. This argument must therefore be used in this case only, not in
the others.
    In ceremonial speeches you will develop your case mainly by
arguing that what has been done is, e.g., noble and useful. The
facts themselves are to be taken on trust; proof of them is only
submitted on those rare occasions when they are not easily credible
or when they have been set down to some one else.
    In political speeches you may maintain that a proposal is
impracticable; or that, though practicable, it is unjust, or will
do no good, or is not so important as its proposer thinks. Note any
falsehoods about irrelevant matters-they will look like proof that
his other statements also are false. Argument by ‘example’ is
highly suitable for political oratory, argument by ‘enthymeme’
better suits forensic. Political oratory deals with future events,
of which it can do no more than quote past events as examples.
Forensic oratory deals with what is or is not now true, which can
better be demonstrated, because not contingent-there is no
contingency in what has now already happened. Do not use a
continuous succession of enthymemes: intersperse them with other
matter, or they will spoil one another’s effect. There are limits
to their number—
    Friend, you have spoken as much as a sensible man would have
spoken. ,as much’ says Homer, not ‘as well’. Nor should you try to
make enthymemes on every point; if you do, you will be acting just
like some students of philosophy, whose conclusions are more
familiar and believable than the premisses from which they draw
them. And avoid the enthymeme form when you are trying to rouse
feeling; for it will either kill the feeling or will itself fall
flat: all simultaneous motions tend to cancel each other either
completely or partially. Nor should you go after the enthymeme form
in a passage where you are depicting character-the process of
demonstration can express neither moral character nor moral
purpose. Maxims should be employed in the Arguments-and in the
Narration too-since these do express character: ‘I have given him
this, though I am quite aware that one should “Trust no man”.’ Or
if you are appealing to the emotions: ‘I do not regret it, though I
have been wronged; if he has the profit on his side, I have justice
on mine.’
    Political oratory is a more difficult task than forensic; and
naturally so, since it deals with the future, whereas the pleader
deals with the past, which, as Epimenides of Crete said, even the
diviners already know. (Epimenides did not practise divination
about the future; only about the obscurities of the past.) Besides,
in forensic oratory you have a basis in the law; and once you have
a starting-point, you can prove anything with comparative ease.
Then again, political oratory affords few chances for those
leisurely digressions in which you may attack your adversary, talk
about yourself, or work on your hearers’ emotions; fewer chances
indeed, than any other affords, unless your set purpose is to
divert your hearers’ attention. Accordingly, if you find yourself
in difficulties, follow the lead of the Athenian speakers, and that
of Isocrates, who makes regular attacks upon people in the course
of a political speech, e.g. upon the Lacedaemonians in the
Panegyricus, and upon Chares in the speech about the allies. In
ceremonial oratory, intersperse your speech with bits of episodic
eulogy, like Isocrates, who is always bringing some one forward for
this purpose. And this is what Gorgias meant by saying that he
always found something to talk about. For if he speaks of Achilles,
he praises Peleus, then Aeacus, then Zeus; and in like manner the
virtue of valour, describing its good results, and saying what it
is like.
    Now if you have proofs to bring forward, bring them forward, and
your moral discourse as well; if you have no enthymemes, then fall
back upon moral discourse: after all, it is more fitting for a good
man to display himself as an honest fellow than as a subtle
reasoner. Refutative enthymemes are more popular than demonstrative
ones: their logical cogency is more striking: the facts about two
opposites always stand out