Roger Bacon

Roger Bacon (c. 1214/1220–1292) was an English Franciscan friar and philosopher, active at Oxford and Paris. He is celebrated as a pioneer of empirical science and the systematic use of mathematics in natural philosophy.

Hermes as Scientific Authority

Bacon repeatedly cited Hermes Trismegistus as a positive authority in his major works, including the Opus Majus. For Bacon, Hermes represented the ancient tradition of scientia experimentalis — knowledge derived from direct experience — making him a proto-scientist rather than a mystic. Bacon drew on the Hermetic astrology and optical theory preserved in Arabic sources (particularly al-Kindi's De Radiis) to develop his theory of the 'multiplication of species' (the propagation of natural forces through the medium of light). His engagement illustrates how Hermetic cosmological principles (correspondence, Sympatheia, number) entered the foundations of early medieval natural science.