Book 5
10.64
since, as he was writing to Trebatius, A famous lawyer, cp. III. xi. 18. v. 17. he preferred to draw his examples from law. I have chosen my illustrations as being more obvious. Properties have relation to questions of fact as well; for instance, it is the property of a good man to act rightly, of an angry man to be violent in speech or action, and consequently we believe that such acts are committed by persons of the appropriate character, or not committed by persons of inappropriate character. For just as certain persons possess certain qualities, so certain others do not possess certain qualities, and the argument is of precisely the same nature, though from opposite premises.
10.65
In a similar way division is valuable both for proof and refutation. For proof, it is sometimes enough to establish one thing. To be a citizen, a man must either have been born or made such. For refutation, both points must be disproved: he was neither born nor made a citizen.
10.66
This may be done in many ways, and constitutes a form of argument by elimination, whereby we show sometimes that the whole is false, sometimes that only that which remains alter the process of elimination is true. An example of the first of these two cases would be: You say that you lent him money. Either you possessed it yourself, received it from another, found it or stole it. If you did not possess it, receive it from another, find or steal it, you did not lend it to him.
