William Gilbert: Magnetism as Astrological Influence, and the Unification of the Terrestrial and Celestial Realms

Abstract

This chapter presents a case study of the natural philosophy of William Gilbert. While saying little about the practice of astrology or the question of extraterrestrial life per se, Gilbert’s cosmology was instrumental in the dissolution of the Aristotelian sublunary/celestial divide, and in the application of terrestrial analogies to questions of celestial physics. As well as Gilbert’s one published work, De magnete (1600), particular attention is paid to his posthumously published De mundo nostro sublunari philosophia nova (1651). The chapter describes and analyses Gilbert’s philosophy in both its terrestrial and celestial dimensions. Celestial influence is shown to be a major component of Gilbert’s system. Gilbert’s theories of magnetism and electricity are also examined, especially in relation to cosmological matters. While he only makes passing reference to a variety of living and animated beings on the surfaces of the celestial globes (plural), the assumption of life on the other celestial bodies in fact plays an important role in his rationale for celestial motion.