THE SOLAR MODEL IN JOSEPH IBN JOSEPH IBN NAHMIAS' 1 LIGHT OF THE WORLD
In an influential article, A. I. Sabra identified an intellectual trend from twelfth and thirteenth-century Andalusia which he described as the ‘‘Andalusian revolt against Ptolemaic astronomy.” Philosophers such as Ibn Rushd (d. 1198 C. E.), Ibn Tufayl (d. 1185), and Maimonides (d. 1204) objected to Ptolemy’s (fl. 125–50) theories on philosophic grounds, not because of shortcomings in the theories' predictive accuracy. Sabra showed how al-Bitruji's (fl. 1200) Kitab al-Hay'a (The Book of Astronomy) attempted to account for observed planetary motions in a way that met the philosophic standards of those philosophers and others. In Nur al-‘alam (Light of the World), the subject of this article, Joseph ibn Joseph ibn Nahmias (fl. ca. 1400) endeavoured to improve upon al-Bitruji’s models. Levi Ben Gerson's (1288–1344) Hebrew writings on astronomy criticized al-Bitruji, but Ibn Nahmias did not mention them. Nur al-‘alam deserves attention, too, because it is the first Arabic text on theoretical astronomy by a Jewish author to come to light. In the body of this article, I will describe and analyze Ibn Nahmias’ theory, from Nur al-‘alam, for the motion of the sun.(Published Online February 16 2005)
1 I would like to thank Bernard R. Goldstein of the University of Pittsburgh and George Saliba of Columbia University for bringing this manuscript to my attention in 1992. I presented part of this paper at the 2002 History of Science Society conference in Milwaukee, WI, and thank Jamil Ragep of the University of Oklahoma for thoughtful comments. I would also like to acknowledge the time and care taken by the anonymous referees at Arabic Sciences and Philosophy. Discussions with Albert and Laura Schueller and David Guichard of the Whitman College Department of Mathematics were also beneficial. Any shortcomings in this article are my responsibility.