Much of institutional theory deals with the problem of getting individuals to act in the common interest. Sometimes, appropriate institutions can sustain cooperation among entirely selfish individuals. At other times, some unselfishness is required. This talk presents a theory of internalized social duties, building on classical contributions by Cicero, David Hume, and Adam Smith. The role of social duties is compared to the role of empathy – as depicted by existing models of social preferences. The theory is related to evidence from laboratory experiments and surveys. It is also used to shed light on practices that aim to build loyalty to shared values.