Basic to Descartes’ account is the distinction he draws between (i) the supreme good, (ii) happiness, and (iii) the final end or goal, notions generally taken as equivalent in ancient eudaimonism (AT IV 275/CSMK 261). Descartes identifies the supreme good with virtue, which he defines as “a firm and constant will to bring about everything we judge to be the best and to employ all the force of our intellect in judging well” (AT IV 277/CSMK 262). Virtue is the supreme good, he argues, because it i