The difference between this one and the last is that, whereas in the last any two things are contrasted, here the things contrasted are opposites. For instance, the priestess enjoined upon her son not to take to public speaking: 'For', she said, 'if you say what is right, men will hate you; if you say what is wrong, the gods will hate you.' The reply might be, 'On the contrary, you ought to take to public speaking: for if you say what is right the gods will love you; if you say what is wrong, men will love you.' This amounts to the proverbial 'buying the marsh with the salt'. It is just this situation, viz. when each of two opposites has both a good and a bad consequence opposite respectively to each other, that has been termed divarication.
15. Another line of argument is this: The things people approve of openly are not those which they approve of secretly: openly, their chief praise is given to justice and nobleness; but in their hearts they prefer their own advantage. Try, in face of this, to establish the point of view which your opponent has not adopted. This is the most effective of the forms of argument that contradict common opinion.
16. Another line is that of rational correspondence. E.g.
Iphicrates, when they were trying to compel his son, a youth under the prescribed age, to perform one of the state duties because he was tall, said 'If you count tall boys men, you will next be voting short men boys'. And Theodectes in his Law said, 'You make citizens of such mercenaries as Strabax and Charidemus, as a reward of their merits; will you not make exiles of such citizens as those who have done irreparable harm among the mercenaries?'
17. Another line is the argument that if two results are the same their antecedents are also the same. For instance, it was a saying of Xenophanes that to assert that the gods had birth is as impious as to say that they die; the consequence of both statements is that there is a time when the gods do not exist. This line of proof assumes generally that the result of any given thing is always the same: e.g. 'you are going to decide not about Isocrates, but about the value of the whole profession of philosophy.' Or, 'to give earth and water' means slavery; or, 'to share in the Common Peace' means obeying orders. We are to make either such assumptions or their opposite, as suits us best.
18. Another line of argument is based on the fact that men do not always make the same choice on a later as on an earlier occasion, but reverse their previous choice. E.g. the following enthymeme: 'When we were exiles, we fought in order to return; now we have returned, it would be strange to choose exile in order not to have to fight.' one occasion, that is, they chose to be true to their homes at the cost of fighting, and on the other to avoid fighting at the cost of deserting their homes.
19. Another line of argument is the assertion that some possible motive for an event or state of things is the real one: e.g. that a gift was given in order to cause pain by its withdrawal. This notion underlies the lines:
God gives to many great prosperity, Not of good God towards them, but to make The ruin of them more conspicuous.
Or take the passage from the Meleager of Antiphon:
To slay no boar, but to be witnesses Of Meleager's prowess unto Greece.
Or the argument in the Ajax of Theodectes, that Diomede chose out Odysseus not to do him honour, but in order that his companion might be a lesser man than himself-such a motive for doing so is quite possible.
20. Another line of argument is common to forensic and deliberative oratory, namely, to consider inducements and deterrents, and the motives people have for doing or avoiding the actions in question. These are the conditions which make us bound to act if they are for us, and to refrain from action if they are against us: that is, we are bound to act if the action is possible, easy, and useful to ourselves or our friends or hurtful to our enemies; this is true even if the action entails loss, provided the loss is outweighed by the solid advantage. A speaker will urge action by pointing to such conditions, and discourage it by pointing to the opposite. These same arguments also form the materials for accusation or defence-the deterrents being pointed out by the defence, and the inducements by the prosecution. As for the defence,...This topic forms the whole Art of Rhetoric both of Pamphilus and of Callippus.