 The role of the Empyrean in thirteenth-century thought is equivocal. Some thinkers attempt to explain it scientifically, as a comprehensive cosmic principle, while for Thomas and Albert any such realm must be spiritual in nature and can bear no natural relation to the astronomical universe—though both at times seem to grant it a certain influence on the natural order [Nardi (1967), 196–214; Vasoli (1995a), 94–102]. Dante’s account reflects these uncertainties. He begins by citing “the Catholics,” or orthodox belief, as authority for his account of this “abode of the supreme deity,” but then goes on to treat the Empyrean as a created thing, “formed in the Primal Mind,” and as the motionless cause of motion in the physical universe. If God dwells in this place, the Empyrean resides equally in Him, and the universe at large is encompassed, causally and locally, by the Empyrean. Dante deploys the Aristotelian physics of desire to explain the relationship of the Empyrean to the lesser heavens, yet it is at the same time beyond space, a wholly spiritual realm where blessed spirits participate in the divine mind. Dante seems to emphasize this double status by mingling theological and philosophical language, and invoking Aristotle and the neo-Platonists side by side with the poet of the Psalms. In the Paradiso the problems raised here will be implicitly resolved by a brilliant recourse to the “metaphysics of light;” when Dante and Beatrice, emerging from the “greatest body,” the crystalline sphere or Primum Mobile, pass on “al ciel ch’è pura luce, / Luce intellettual piena d’amore” [Par. 30.39–40], we know that we are at the precise point at which the bonum diffusivum sui that is God’s love transforms itself to cosmic energy, “the love that moves the sun and the other stars.” But poetry is perhaps the only means of defining this threshold [Bonaventure, Sent. 2. d. 2, a. 2, q. 1, c. 4; Thomas, Quodl. 6, q. 11, a. unicus 19].