30 ASTRONCMY IN ANCIENT NATIONS Ibn Tofeil Ibn Tofeil, the second of the three Moslem philosophers of Spain, vizier and physician at the court of Jusuf ben Abd el Mumin of Morocco, seems to have walked in the footsteps of his master; but the only extant work of his, a kind of religious mystic romance about the emancipation of a soul from the trammels of this material world, does not give any clue to his ideas as to the planetary system. But Averroes, who also objected to the excentrics and epicycles says in his commentary to Aristo- tle's Metaphysics that Ibn Tofeil possessed on this subject excellent theories, and Ibn Tofeil's pupil, the astronomer Al Betrugi, in the introduction to his theory of the planets, says of him: "You know that the illustrious judge Abu Bekar Ibn Tofeil told us that he had found an astronomical system and principles of the various movements different from those laid down by Ptolemy and without admitting either excentrics or epicycles, and with this system all the motions are represented without error." Ibn Tofeil was therefore probably the real author of the fairly elabo- rate system, which his pupil worked out and handed down to us in a work on the planets, which was translated into Hebrew in the following century and from that again into Latin, and published in 1531 ³. The object of this system was to explain the constitution of the universe as it really is, and not merely to represent the motions of the planets geometrically, so as to be able to foretell their places in the heavens at any time; and the author (be he Ibn Tofeil or Al Betrugi alias Alpetragius) specially disclaims any intention of testing the theory by comparing it with observations (Continued from previous page) Aristotle says is true, there is neither epicycle nor excentric, and every- thing turns round the centre of the Earth, 2. Munk; Melanges de philosophie juive et arabe. Paris, 1859, p. 412. 3. Alpetragii Arabi Planetarum theorica phisicis rationibus probata, nuperrime latinis litteris mandata a Calo Calonymos, Hebreo Neapolitano, Venice 1531, 28 ff. folio (published with Sacrobosco's Sphaera). A translation by the famous Micheal Scot has never been printed, but is still extant in Paris (Munk, Melanges, p. 519). The principle of the system is described by Isaac Israeli, who, however, does not mention the author's name (Liber Jesed Olam, II. 9. Part I, p. XI
