Institutio Oratoria

For when it has been asserted and denied that a deed was done, the question whether it was done is resolved by conjecture, and the decision of the judge and the main question rest on the same ground, since the first question and the final decision are concerned with the same point. But when it is stated and denied that Orestes was justified in killing his mother, considerations of quality are introduced: the question is whether he was justified in killing her, but this is not yet the point for the decision of the judge. When, then, does it become so?

She killed my father.

Yes, but that did not make it your duty to murder your mother.

As regards the foundation, I will put

The foundation is the strongest argument for the defence, as for instance, if Orestes were ready to say that the disposition of his mother towards his father, himself and his sisters, the kingdom, the reputation of the race and the family were such that it was the peculiar duty of her children to punish her.

Others again use illustrations such as the following:—

He who has spent his patrimony, is not allowed to address the people.

But he spent it on public works.

Or again take the case of the soldier Arruntius, who killed the tribune Lusius for assaulting his honour. The question is whether he was justified in so doing, the line of defence, that the murdered man made an assault upon his honour, the point for the decision of the judge, whether it was right that a man should be killed uncondemned or a tribune by a soldier.

Some even regard the basis of the question as being different from the basis of the decision. The question as to whether Milo was justified in killing Clodius, is one of quality. The point for the decision of the judge, namely whether Clodius lay in wait for Milo, is a matter for conjecture.