Cicero's On Duties: The Honorable and the Useful

Cicero's last philosophical work, De Officiis (On Duties), written in late 44 BCE for his son Marcus, who was studying in Athens, became one of the most influential books on ethics ever written. Drawing on the Stoic Panaetius, Cicero discussed how to act rightly in public and private life. He considered first what is honorable (honestum), then what is useful (utile), and finally what to do when the two seem to conflict.

His answer was that true conflict is impossible: whatever is dishonorable cannot truly be useful, even if it brings profit. He tested this with hard cases, such as a merchant who knows other grain ships are coming during a famine: must he tell buyers? Cicero also stressed duties of justice, generosity and keeping promises, even to enemies. Written months after Caesar's assassination, the book also reflects Cicero's defense of the Republic against tyranny.