Marcus Atilius Regulus commanded the Roman army in the first Carthaginian war, until he lost a battle and was captured in 255 BC. After a spell in captivity, he was despatched to Rome to try to exchange himself for some high-ranking prisoners. To kindle his ardour, the Carthaginians extracted an oath from him that, if the mission failed, he would return to Carthage to be put to death by torture. On reaching Rome, however, he urged the Senate to refuse, since the prisoners were worth more to Carthage than he to Rome. His advice carried the day. Then, unmoved by the pleas of friends and peers, he insisted on keeping his oath. He sailed back to Carthage, where he was returned to prison and kept awake until he died.

Cicero introduces this memorable story into a discussion of duty and expediency, as ‘a real event in our history’, illustrating his theme that what is truly expedient is what is truly right (De Officiisiii.26). It will do nicely to examine the notion of rationality as rational role-playing and to pose some epistemic questions about understanding (Verstehen) and explaining (Erklären). There is also a twist to the tale, as will be revealed later, when we come to the hermeneutic circle. Meanwhile let us ask whether we can understand and explain Regulus' course of action as one rationally chosen by a Roman general in the dawn of the Republic. I shall deploy the answer suggested by the previous chapter, giving it a Weberian frame and thus pointing up some epistemological problems of this style of analysis.