Sources of proof
Know the areas where you must hunt for, and track down what you are trying to find. Once you have surrounded the entire place with the nets of your thought, at least if practical experience has sharpened your skill, nothing will escape you and everything that is in the subject matter will run up to you and fall into your hands.
Marcus Tullius Cicero, De Oratore
Logos (rational argumentation)
Rational argumentation has its foundation in two basic processes, induction by the use of example and deduction through syllogistic reasoning.
Examples, can be fictitious or historical, and from them you can argue by inducing a probable conclusion about the matter in dispute, and then offer a general or universal application drawn from the specific example in question.
- Present one or more similar cases
- State the point we want conceded, for which the similar cases have been cited.
- Draw a conclusion that reinforces the concession or demonstrates what results follow from it.
A syllogism has the basic form of major premise, minor premise, and conclusion, for example:
“All human beings are mortal; Cicero is a human being; therefore, Cicero is mortal.”
In speeches and oral arguments, a speaker often relies on premises that are probable and not necessarily certain, and sometimes even omits the minor premise. This sort of “rhetorical syllogism” is known as an enthymeme. In its most expansive, five-part form, called the epicheireme, a syllogism’s major and minor premises are supported by further arguments, and then the conclusion is drawn.
Ethos (argument based on character)
This is persuasion gained through the effective presentation of the speaker’s character or the character of the person on whose behalf the speaker is pleading. The goal is to win the approval and admiration of your audience, which makes them ultimately more sympathetic to your argument.
Negative character portrayal of your opponent is also an effective way to help your listeners side with your point of view.
People’s minds are won over by a man’s prestige, his accomplishments, and the reputation he has acquired by his way of life. Such things are easier to embellish if present than to fabricate if totally lacking, but at any rate, their effect is enhanced by a gentle tone of voice on the part of the orator, an expression on his face intimating restraint, and kindliness in the use of his words, and if you press some point rather vigorously, by seeming to act against your inclination, because you are forced to do so.
Indications of flexibility are also quite useful, as well as signs of generosity, mildness, dutifulness, gratitude, and of not being desirous or greedy.
Actually, all qualities typical of people who are decent and unassuming, not severe, not obstinate, not litigious, not harsh, really win goodwill, and alienate the audience from those who do not possess them.
In this regard, I pass over what could have been an extremely powerful argument for me in maintaining Roscius’s innocence— the fact that crimes of this sort are not generally born amid rustic manners, a frugal mode of living, a life rough and uncultured. Just as you cannot find every sort of crop or tree growing in every sort of soil, so every kind of life does not give birth to every kind of crime. The city breeds prodigality, and from prodigality greed necessarily develops, and from greed audacity bursts forth, from which all crimes and evil deeds are born. On the other hand, this rustic sort of life, which you call countrified, is the teacher of thriftiness, diligence, and justice
Pathos (argument based on emotional appeal)
This is persuasion won through appeal to the audience’s emotions. The speaker’s goal is to sway, or move the feelings of his listeners so that they will side emotionally with him. Appealing to the emotions is a tactic as old as speech itself, and the Greeks and the Romans employed both verbal and nonverbal appeals.
One might recall that Socrates, in his defense called the Apology, asserted that he would not resort to emotional appeals, for example, bringing his children into the courtroom dressed in mourning clothes to secure his acquittal. Cicero realized the great power of argument based on emotional appeal, calling it the most effective means of persuasion.
According to Cicero, ethos involved knowledge and exploitation of the milder emotions, while pathos dealt with the more violent emotions.
Of course, the most desirable situation for the orator is when the jurors themselves come to the case in an emotional state of mind, suited to what his own interests demand. For, as the saying goes, it is easier to spur on a willing horse than to rouse a sluggish one
My method is that of a diligent doctor: before attempting to apply treatment to a patient, he must find out not only about the disease of the person he wants to cure, but also about his routine when healthy and his physical constitution. […] when I set out to work upon the emotions of the jurors in a difficult and uncertain case, I carefully concentrate all of my thoughts on considering […] what their feelings, their opinions, their hopes, and their wishes are, and in what direction my speech may most easily lead them. If they put themselves into my hands and, as I just said, are inclined, of their own accord, to lean in the direction I am pushing them, I accept what is offered and spread my sails to catch any breeze that happens to be blowing. If, however, the jurors are unbiased and unemotional, more effort is required;[…] it cannot only straighten up someone who is bending over and bend over someone who is standing, but also, like a good and brave general, take prisoner someone who is offering resistance and fighting back.