Dusseldorf/Chapters/7-rbacon.rtf, cr 26 nov 2004

7. Roger Bacon, 1267 CE

In De multiplicatione specierum, around 1267, Bacon presents a doctrine of the physics of light. 
He was inspired by Plotinus (d. 270), al-Kindi (d. c. 873), and Roger Grosseteste (c. 1168-1253). This doctrine survived for three centuries, and ended with John Dee (d. 1607). The word species meant the likeness of any object, transmitted through any media. The background is given in (Lindberg, 1983; pp. xxxv-liii): esp. Plato, the Old Testament, Philo, Plotinus, St. Augustine (d. 430), Proclus (d. 485), and al-Kindi.

Refs

Lindberg, David C. Theories of Vision from al-Kindi to Kepler. Chicago: Univ. of Chicao Press, 1976.

Lindberg, David C. Roger Bacon's Philosophy of Nature. Oxford: Oxford Univ. Press, 1983.
English translation of De multiplicatione specierum, and De speculis comburentibus.

Lindberg, David C. Roger Bacon and the Origins of Perspectiva in the Middle Ages. Oxford: Oxford Univ. Press, 1996. English translation of Perspectiva.