Kitap 3
5.4
This main question, then, they call the ζήτημα. The line of defence is the method by which an admitted act is defended. I see no reason why I should not use the same example to illustrate this point that has been used by practically all my predecessors. Orestes has killed his mother: the fact is admitted. He pleads that he was justified in so doing: the basis will be one of quality, the question, whether he was justified in his action, the line of defence that Clytemnestra killed her husband, Orestes' father. This is called the αἴτιον or motive. The point for the decision of the judge is known as the κρινόμενον and in this case is whether it was right that even a guilty mother should be killed by her son.
5.5
Some have drawn a distinction between αἴτιον and αἰτίαν making αἴτιον mean the cause of the trial, namely the murder of Clytemnestra, αἰτία the motive urged in defence, namely the murder of Agamemnon. But there is such lack of agreement over these two words, that some make αἰτία the cause of the trial and αἴτιον the motive of the deed, while others reverse the meanings. If we turn to Latin writers we find that some have given these causes the names of initinum, the beginning, and ratio, the reason, while others give the same name to both.
