| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 572 |
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Ibn Ṭufayl: Abū Bakr Muḥammad ibn ʿAbd al‐Malik ibn Muḥammad ibn Muḥammad ibn Ṭufayl al‐Qaysī
Miquel Forcada
Alternate
name
Abubacer
Died Marrakech
(Morocco), 1185/1186
Ibn
Ṭufayl was one of the Spanish philosophers
who objected to major parts of the Ptolemaic system. We have little information
about Ibn Ṭufayl'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 Ṭufayl 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, Biṭrūjī
informs us in his Kitāb al‐Hayʾa that Ibn Ṭufayl 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. Biṭrūjī goes on to say
that Ibn Ṭufayl
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 Ṭufayl'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 Ṭufayl 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 Ṭufayl
may have had, he must have kept his alternative system to himself because
Ibn Rushd does not mention a single idea of Ibn Ṭufayl on the matter, and Biṭrūjī
states that his Kitāb al‐Hayʾa, the only cosmological
proposal deriving from this “revolt,” was the result of his own efforts and
research.
Ibn
Ṭufayl's most important work,
the philosophical romance Risālat Ḥayy ibn Yaqẓān, has several references
to astronomy. As is well known, the book describes the process of self‐education
by a child Ḥayy, 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 Ḥayy'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 Ṭufayl'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 Biṭrūjī
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‐Biṭrūjī: 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‐Biṭrūjī.” 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.