The theory of spiritual substances.
Since William attributes so much of magic to demons, it is important to note what he has to say concerning these “spiritual substances.” He proposes to follow as his sources on the subject “authentic accounts” (sermones authentici): first of all the statements of the divinely inspired prophets, and after that the opinions of the philosophers and also of the magicians. He observes elsewhere, however, that there is a lack of literature on the subject; the sages have only dipped into it and not yet plumbed it to its depths: in fact, only the treatise of Avicenbros has come to his hands, and while that authority has said and written many sublime things, far removed from popular comprehension, still he has made only a beginning in this field.[1169] William also utilizes, however, the works of Hermes Trismegistus[1170] and other books of necromancy and magic—among them Thot Graecus[1171]—the testimony of medical men[1172] and “innumerable experiences” of men at large.[1173]
William professes himself open to conviction and new light on the question of the assumption of bodies by good and bad spirits.[1174] And it must be said that his whole treatment of spirits is full of inconsistencies and difficulties. Part of the time he draws a hard and fast line between spiritual substances and physical creation, but only part of the time. He also essays the difficult task of explaining how and to what extent these spiritual substances are able to disturb physical creation, and how far they in turn are affected by it.
Spirits in the heavens.
To begin with, William takes up the difficult position—or rather he makes it difficult for himself—but the usual one with medieval theologians, that angels occupy physical space and are located in their own heaven as the stars are in theirs.[1175] Some modern believers in spiritualism hold a very similar position.[1176] He also declares that the tenth and last or empyrean heaven will be the eternal abode of men whose souls are saved, although the resurrected bodies of the saved would presumably still be corporal substances.[1177] This raises the further difficulty that apparently the empyrean heaven cannot be the abode of the angels, as some theologians and saintly doctors have held (for a corporal place cannot be filled except with corporal substances), for those superficial persons who mock the authentic divine revelation of scripture will say that “if that heaven is a corporal place it cannot be filled except by corporal substances.”
Will hell be big enough?
Another point which puzzles William is whether there will be room in hell for all the evil spirits and resurrected bodies of the damned destined to make it their ultimate abode. The infernal regions, located in the interior of our terrestrial globe, seem very small to him compared with the vast expanse of the empyrean heaven which is even greater than that of the fixed stars. And our earth is a mere dot compared to the sphere of the fixed stars. If then that entire empyrean heaven is to be filled with glorified men, how shall the infernal regions hold all the damned?[1178] It will be seen that Dante’s later cosmology is very similar to William’s.
Astrological necromancy.
William will not agree, however,[1179] with the books of magic and the masters of images and illusions that the starry heavens and even single planets are inhabited by spirits so that the circle of the moon has fifty ministering spirits and that there are also angels in the twelve signs of the zodiac. On the other hand, in an earlier chapter he makes the statement that he has never heard anywhere even in magic books of demons with power over celestial bodies.[1180] William is of the opinion that Aristotle was deceived by an evil spirit into boasting that a spirit had descended to him from the circle of Venus.[1181] William argues that the starry heavens are rational and able to regulate themselves and do not require any ministering angels; and on the other hand that the nobler spirits would not debase themselves by ministering to mere celestial bodies.[1182] William’s own theory is that demons dwell in the air about the earth and not in the planetary heavens. He also speaks in one passage of their especially frequenting deserts.[1183]
False accounts of fallen angels.