From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 572

Courtesy of

Ibn ufayl: Abū Bakr Muammad ibn ʿAbd al‐Malik ibn Muammad ibn Muammad ibn ufayl al‐Qaysī

Miquel Forcada

Alternate name


BornGuadix, Purchena, or Tíjola (Spain), beginning of the 12th century

DiedMarrakech (Morocco), 1185/1186

Ibn ufayl was one of the Spanish philosophers who objected to major parts of the Ptolemaic system. We have little information about Ibn ufayl's formative period and early days. He seems to have worked for local rulers till he became secretary to the governor of Ceuta and Tangier, thus entering the service of the Almohads, the North African dynasty that ruled Muslim Spain (al‐Andalus) and North Africa from the middle of the 12th century onward. He then became court physician and counselor to the caliph Abū Yaʿqūb Yūsuf, a sovereign who loved and supported science and thought. In this post, Ibn ufayl seems to have promoted most of the scientific and philosophical enterprises that characterize this period, encouraging his disciples to develop his suggestions. We know that he inspired Ibn Rushd's systematic commentary of Aristotle and, perhaps, his writing of a medical manual. As for astronomy, Birūjī informs us in his Kitāb al‐Hayʾa that Ibn ufayl conceived a cosmological system (hayʾa) that described planetary motion without having recourse to Ptolemaic eccentrics and epicycles, which violated the Aristotelian principles of uniform and circular motions centered on the Earth. Birūjī goes on to say that Ibn ufayl promised to write a book about his system, but, as far as we know, he never did so. This information is the only evidence of Ibn ufayl's concern with this question, and, in spite of its brevity, is consistent with our knowledge of the “Andalusian revolt against Ptolemy.” On the one hand, Ibn ufayl was aware of the works of the philosopher who paved the way for this “revolt,” Ibn Bājja; on the other hand, his closest disciple, Ibn Rushd, devoted much time and effort to studying the problem. Nonetheless, whatever intuitions Ibn ufayl may have had, he must have kept his alternative system to himself because Ibn Rushd does not mention a single idea of Ibn ufayl on the matter, and Birūjī states that his Kitāb al‐Hayʾa, the only cosmological proposal deriving from this “revolt,” was the result of his own efforts and research.

Ibn ufayl's most important work, the philosophical romance Risālat ayy ibn Yaqān, has several references to astronomy. As is well known, the book describes the process of self‐education by a child ayy, either the son of a princess or born by spontaneous generation, who grows up abandoned on a desert island. By means of his own understanding, he is able to discover all kinds of truth and knowledge: technical, physical, philosophical, and spiritual. The study of the heavens plays an essential role in ayy's inquiries; he is able to ascertain the mechanics of celestial bodies without the help of others. The paragraphs devoted to this question mainly deal with the philosophical sides of cosmology (the souls of celestial bodies, their influence on the sublunary world, etc.) to the extent that it is difficult to deduce anything really useful from them about Ibn ufayl's astronomical thought. Nevertheless, a passage in which he mentions that the celestial bodies can move either around their own center or around another center suggests that, in spite of what Birūjī says, the author may have accepted eccentrics at some stage, thus sharing the opinion of Ibn Bājja.

Selected References

Conrad, Lawrence I. (ed.) (1996). The World of Ibn Ṭufayl: Interdisciplinary Perspectives on Ḥayy ibn Yaqẓān. Leiden: E. J. Brill.

Forcada, Miquel (1999). “La ciencia en Averroes.” In Averroes y los averroísmos: Actas del III Congreso Nacional de Filosofía Medieval, pp. 49–102. Zaragoza: Sociedad de Filosofía Medieval.

Goldstein, Bernard R. (1971). Al‐Birūjī: On the Principles of Astronomy. 2 vols. New Haven: Yale University Press.

Goodman, Lenn E. (1996). “Ibn Ṭufayl.” In History of Islamic Philosophy, edited by Seyyed Hossein Nasr and Oliver Leaman, pp. 313–329. London: Routledge.

Ibn Ṭufayl (1936). Risālat Ḥayy ibn Yaqẓān, edited and translated into French by L. Gauthier. Beirut: Imprimerie Catholique. (Translated into English by L. E. Goodman as Ibn Ṭufayl's Ḥayy b. Yaqẓān, a Philosophical Tale. New York, 1972.)

Sabra, A. I. (1984). “The Andalusian Revolt against Ptolemaic Astronomy: Averroes and al‐Birūjī.” In Transformation and Tradition in the Sciences, edited by Everett Mendelsohn, pp. 133–153. Cambridge: Cambridge University Press. (Reprinted in Sabra, Optics, Astronomy and Logic, XV. Aldershot: Ashgate, 1994.)

Samsó, Julio (1992). Las ciencias de los antiguos en al‐Andalus. Madrid: Mapfre.