 Yet this still leaves open the question of how to assess the value of these other goods. The supreme good, virtue, consists in a firm resolution to bring about whatever reason judges to be the best. But on the basis of what does reason make this determination? What knowledge allows reason to form a well-founded judgment about the goodness and badness of objects, in the pursuit of which we act virtuously? Descartes criticizes Seneca on just this point—that he fails to teach us “all the principal truths whose knowledge is necessary to facilitate the practice of virtue and to regulate our desires and passions, and thus to enjoy natural happiness” (AT IV 267/CSMK 258). In response, Elisabeth worries that Descartes’ account, which promises the attainment of happiness, might presuppose more knowledge than we can possibly possess. In assuaging her concern, Descartes summarizes the knowledge he believes we can rely on in directing the will toward virtuous ends. It consists of a surprisingly small set of “the truths most useful to us.” The first two are basic principles of Cartesian metaphysics as presented in the Meditations: