One of the most interesting and significant features of the history of early optics is its continuity across cultural and linguistic boundaries. This is not, of course, to suggest that the science of optics remained totally static, escaping all need to adapt to changing cultural, linguistic and philosophical circumstances. But it is important to understand that despite development and adaptation, optics retained a recognizable identity from the ancient Greeks to the beginning of the seventeenth century.
This continuity is particularly striking from Ibn al-Haytham in the eleventh century to Johannes Kepler in the seventeenth. Although it is indisputable that optical theory saw interesting and important developments during this period, there was surprisingly little change in the questions to which it was addressed, the basic assumptions on which it was founded and the criteria of theoretical success that it had to meet. Central, therefore, to the history of early optics is the problem of transmission and assimilation. This chapter will be devoted to the Latin reception of Arabic optics.
Before the translations of the twelfth and thirteenth centuries, the West had access to only the most meager optical fare. In the encyclopaedias of Pliny the Elder (d. AD 79), Solinus (fl. third or fourth century) and Isidore of Seville (seventh century), one finds elementary discussions of various optical phenomena, but optical theory only at the most rudimentary level. We learn, for example, that sight occurs by light issuing from the eye, that the seat of vision is the pupil or centre of the eye, that light moves more swiftly than sound, that Tiberius Caesar could see in the dark and that a rainbow is caused by solar light incident on a hollow cloud. We also learn