  In Cardano’s metaphysics, matter and form are complementary, in that in nature there cannot be matter without form, and forms are always with a body. Forms represent the primordial stage in the process through which the created universe becomes one living being. The difference between souls and forms is that souls, albeit involved in the animation of bodies, remain nevertheless unaffected by corporeal reality. Up on a higher level, minds are souls that are completely independent of matter, bodies and motion. However, even within the ontological sphere of the minds, there are varying degrees of embodiment. While the highest celestial intelligences are wholly separated from the material cosmos, demonic substances, albeit incorporeal, can affect the corporeal world through forces (vires) and influences (influxus) of various kind. One of these is “that force which is connected to demons, regardless of whether this power is corporeal and depends on humours, or it is incorporeal.” Cardano maintains that it is through forces of this nature that “the parts of the universe are aroused by demons, stars or some other hidden cause” (Paralipomena, in OO, X, 446b–447a. See also De subtilitate, OO, III, 670a). The principle that in a way collects and administers all these currents of celestial energy is the soul of the world (anima mundi). In Cardano’s system of astro-biological determinism, the universal soul keeps the whole cosmos together and performs paramount operations in accordance with the original plan devised by God and implemented by the planetary intelligences, for “all things are influenced by the higher heaven and are moved at the command of the soul of the world.” The soul of the world, which “cannot be understood without God,” directs the work of nature, and, “in the process of generating things, produces supercelestial lives and multiplicity” (De arcanis aeternitatis, OO, X, 6a). In the sublunary world, the major operations of life and generation are performed by nature, understood as a source of teleological activity supervised by the intellect and the soul of the world (De subtilitate, OO, III, 360a; ed. Nenci, 63). The complex relationship between soul and nature, and the role played by celestial forces, is a crucial point in Cardano’s philosophy (On Cardano’s cosmological views, see Ingegno 1980, 1–78, 209–271; Maclean 1984; Grafton 1999).