 Analysis of the fine structure of Descartes’ ethical theory and its relation to ancient eudaimonist theories has emerged as an active area of research in recent years. Among the issues debated are the content of Descartes’ notion of virtue, the identity of virtue and a human being’s highest good, and the sufficiency of virtue for happiness. While defending different answers to these questions, scholars have broadly agreed in seeing Descartes as advancing an original ethical theory that critically engages the positions of Aristotle, Epicurus, and the Stoics. (For competing readings, some of which diverge from the account presented here, see Alanen 2009; Gueroult 1985; Naaman-Zauderer 2010; Rutherford 2004, 2014; Santilli 1992; Shapiro 2008, 2011; Svensson 2010, 2011, 2015, 2019a, 2019b, 2020; Viljanen 2021; Wienand 2012; Youpa 2013.)