 Early in the third book Dante cites the Liber de Causis: every “substantial form” proceeds from the first cause, God, and participates in His divine nature according to its nobility [3.2.4–8; LC 1.1]. The human soul, noblest of all created forms, loves all things to the degree that they manifest the divine goodness, but desires above all to be united with God. Philosophy is the expression of this desire in such a way that it, “apart from the soul and considered in itself, has for its subject understanding and for its form an almost divine love for what is understood” [3.11.13]. Thus it is through the love of philosophy—“the spiritual union of the soul with” [3.2.3] philosophy itself—that humanity perfects its “highest nature, in other words the truly human one—or better, the angelic or rational nature” [3.3.11]. For in this spiritual union, the soul discovers in itself “that fine and most precious part of the soul, which is deity” [3.2.19] and “participates in the divine nature in the manner of a sempiternal Intelligence” [3.2.14]. As such it mirrors the nobility, wisdom and love of the divine essence and its “loving use of wisdom” becomes unified with God “through eternal marriage” [3.12.11–14].