ABSTRACT
WILLIAM H.SHERMAN See also Encyclopedias; Humanism; Illustration; Printing; Translations
Until the early seventeenth century, the nature of light and its transmission was conceived in a basically Aristotelian fashion. According to Aristotle (384-322 B.C.E.), light is the instantaneous actualization of the transparency of the medium between observer and object. This actualization enables the colors of the object-the actual object of vision-to be transferred through the medium. During the Middle Ages, Roger Bacon (ca. 1220-ca. 1292), in particular, developed the concept of multiplicatio specierum, in which light was viewed as the multiplication of properties of an object through the surrounding medium. The sixteenth century saw a revaluation of alternative conceptions like the atomistic theory of light, in which light was regarded as local motion of particles. Theories in which light was conceived as a modification of a medium remained, however, the mainstream.
