ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

28 ASTRONOMY IN ANCIENT NATIONS
substitute any other system and does not object to the general
principles of the Ptolemaic system.¹
Three great names :
Ibn Badja, Ibn Tofeil (Abubacer) and Abu Welid (Averroes)
Geber's attempts to pick holes in the work of Ptolemy were,
perhaps, not unconnected with the rapid rise of Aristotelean philo-
sophy in Spain in the twelfth century, which, though not destined
to last long, nevertheless exercised a considerable influence on the
spread of knowledge of Aristotle in the Christian world, while it
cast a halo round the Caliphate of Cordova, which at that time,
under the enlightened rule of the Almohades, seemed to have
reestablished the glory of the best days of the Moslem world.
Three names are specially associated with this movement :
(i) Abu Bekr Muhammed Ibn Jahya al Sayeg, called Ibn
Badja (of Saragossa, died 1139), known as Avempace
among the Scholastics ;
(ii) his pupil Muhammed ben Abdelmelik Ibn Tofeil (of
Granada, died 1185-1186), called Abubacer by the
Scholastics ;
(iii) and finally the greatest philosopher of Islam, Ibn Rosd
Abu Welid, known as Averroes (1126-1198).
In studying Aristotle they laid special stress on his scientific
works, and did not, like their Christian successors, think of
little but dialectics. The acceptance of the system of homocentric
spheres or some modification of it must, therefore, have seemed a
necessity to the Arabian philosophers and this, of course, led
them to reject the theory of epicycles.. The little we know of the
opinions of Ibn Badja on this subject is found in the famous
work The Guide of the Perplexed of the great Jewish scholar
Moses ben Maimun of Cordova, better known as Maimonides,
who tells us that he had his information from a pupil of Ibn
Badja. Like Geber (with whose son he had been familiar),
Maimonides doubted that Mercury and Venus were nearer than

1. Copernicus possessed a copy of Geber's book; which is now in the Univer-
   sity library at Upsala. On the title page, after the author's name, he has
   written: "Egregii, Calumniatoris Ptolemaei," while a number of marginal
   notes show that he has read the book carefully. Curtze, Mittheilungen des
   Coppernicus Vereins, I, p. 37.