Four virtues that together yield happiness
Happiness for nations and cities comes from four kinds of human things: theoretical virtue, deliberative virtue, moral virtue, and practical arts. Theoretical virtue knows the beings and their causes. Deliberative virtue works out what is most useful in particular circumstances, moral virtue gives the character to want it, and practical arts carry it out. No single virtue is enough; each depends on the ones above it to direct it and the ones below it to make it real.