gems, optics, Arabic mineralogy, history of science

The ancient and medieval science of optics, which used geometry to describe the behavior of corporeal rays (whether conceived of as visual or as luminous) in both the sublunar region of the four Empedoclean elements and in the celestial region of the ether, uniquely combined mathematics with terrestrial and celestial physics. This characteristic made it an ideal tool with which to probe some aspects of the material universe. But optics was also the science which investigated the manner in which our most striking sense-perception, vision, occurs, and could, therefore, be of fundamental importance in a theory of epistemology. These (and other) potential uses of optics attracted the attention of one of the greatest of medieval scientists, Ibn al-Haytham. In his efforts to investigate as thoroughly as possible the phenomena of light and of vision and to establish as convincingly as possible their natures so that they might become the bases of a new interpretation of the perceptible world, Ibn al-Haytham devised a scientific methodology that, in its rigor, in the roles that it assigned to observation and experimentation, and in its theory of induction, decisively departed from the traditions of Greek and of earlier Islamic science, and anticipated in many respects the “new” approach of European scientists in the sixteenth and seventeenth centuries. In this book Dr. Omar has painstakingly analyzed this methodology as Ibn al-Haytham employs it in his Optics; has carefully compared and contrasted it with those of his Greek and Arabic predecessors; and has ingeniously tested it by reconstructing some of the instruments devised by Ibn al-Haytham and by reproducing some of his experiments. As a result we can now better understand how Ibn al-Haytham determined the nature of light and the laws governing its behavior, and more fully appreciate the genius with which he approached the study of nature.—David Pingree