John Dee's Natural Philosophy: Between Science and Religion.

It will be hard to find a Renaissance subject more elusive than John Dee and even harder to produce an account of Dee clearer or more satisfying than Nicholas Clulee's splendid book. Since I. R. Calder's groundbreaking dissertation of 1952, Dee has not lacked for investigators; he was a special favorite of Frances Yates. But no one before Clulee has understood Dee so fully or presented him so well to modern readers. For historians of early modern science, philosophy and religion, John Dee's Natural Philosophy offers us a model of patient, precise, persuasive scholarship.

Clulee concentrates on Dee's four main productions in and around natural philosophy. He interprets the Propaedeumata aphoristica as a work of astrology dealing with physical effects described by mathematics, not by a metaphysics of light but by a geometric optics. Although Yates and others portrayed Dee as a Hermetic magus inspired by Renaissance Neoplatonism, Clulee shows that the sources of the Propaedeumata were mainly medieval and that Aristotle still ruled in Dee's mental universe when he wrote this book in 1558. Al-Kindi, Grosseteste and especially Roger Bacon led Dee to his optical astrology, and Aristotelian ideas of method enabled him to treat it as a demonstrative science of nature. In the Monas hieroglyphica of 1564, Dee shifted his focus from astrology to alchemy and from scholastic natural philosophy to Cabalist theories of language. Some features of the Monas, such as Bacon's numerology, connect it with the Propaedeumata, and Dee's continuing naturalism moved him to transform the verbal Cabala that he saw in the Jewish tradition into a new Cabala of the real in which alchemy - a lower earthly astrology mirroring the higher astrology of the heavens - discloses the secrets that God spoke into the world when he created it alchemically. The book called Monas is about the sign called "Monas," the famous hieroglyph in which Dee distilled his mystical cosmogony. Guided by the Monas, the alchemist becomes an adeptivus, rising toward God in an ascent that imitates the primal divine alchemy and transcends the base work of transforming metals. The soteriology of the Monas is absent in the Propaedeumata, whose astrological naturalism bypasses the personal spiritual forces inevitably encountered in a gnostic soul-voyage. The Monas also looked to new sources: Proclus, Trithemius and the Voarchadumia of Joannes Pantheus. Clulee's excavation of Dee's links to thinkers as obscure as Pantheus is impressive; even more impressive is the brilliant deciphering of the intricate Monas that this erudition permits.

Dee's best known work appeared in 1570, a "Mathematicall Praeface" to Euclid; its conception of natural philosophy is empirical, mathematical and practical, and to that extent it foreshadows the scientific revolution. Behind Dee's wish to make the mathematical arts useful to society was his admiration of Roger Bacon. Although the "Praeface" reverts to the naturalism of the Propaedeumata and avoids the mysticism of the Monas, its core is a philosophy of mathematics taken from Proclus and laden with Neoplatonic metaphysics. Dee could scarcely accept Aristotle's exclusion of mathematics from physics, but he still wanted mathematical astrology to meet Aristotelian standards of demonstrative knowledge. Tying mathematics to nature was the loose weave of practice and observation that Dee (following Thomas Norton) called "archemastrie," which included "the science Alnirangiat" (identified by Clulee as natural magic) as well as a divinatory ars sintrillia or catoptromancy. Clulee worries more than he should - a little whiggishly, perhaps - about the place of these magical elements in a work often praised as progressive. In any case, the last part of Clulee's splendid book and of Dee's intellectual career centers on something much more arcane, the Libri mysteriorum that record conversations among Dee, Edward Kelly and the angels whom they heard speaking to them. In these impenetrable texts Dee describes the theurgy wherein angelic revelation - not experience or mathematics - became the main channel not only of apocalyptic prophecy but also of natural knowledge. Although I stand in awe of Clulee's skillful decoding of Dee's enigmas, I might adjust his interpretation of them in one respect: by not importing our notions of "science" into a past so remote from us. If the point of intellectual history is track the ancestry of our ideas, Dee's work is a by-path, a dead end, finally, in the genealogy of thought, but if history is to be about the past in its own terms, Clulee's superb book offers us a voyage on the busiest highways of early modern culture.

Brian P. Copenhaver UNIVERSITY OF CALIFORNIA, LOS ANGELES