Coming after Muʾayyad al-Dīn al-ʿUrḍī and Naṣīr al-Dīn al-Ṭūsī, Quṭb al-Dīn al-Shīrāzī, a leading figure of the so-called Marāgha school in astronomy, presents his predecessors’ non-Ptolemaic models and criticizes them in his threehayʾabooks. Since his own new models inNihāyat al-idrāk andIkhtiyārāt muẓaffarī are not without difficulties, in his latest book onhayʾa,al-Tuḥfa al-shāhiyya he puts forward his modified models inspired from Ṭūsī’s and ʿUrḍī’s models and produces a series of new models for Mercury and the oscillation of the spheres. Nevertheless, in (...) spite of all his attempts, the tradition of non-Ptolemaic modeling after him never converged to a series of standard models.RésuméVenu après Muʾayyad al-Dīn al-ʿUrḍī et Naṣīr al-Dīn al-Ṭūsī, Quṭb al-Dīn al-Shīrāzī, éminente figure de l’école dite de Marāgha en astronomie, présente, dans ses trois ouvrages dehayʾa, les modèles de ses prédécesseurs tout en les critiquant. Puisque ses propres nouveaux modèles, présentés dansNihāyat al-idrāk etIkhtiyārāt muẓaffarī, ne sont pas sans difficulté, il présente, dans son dernier ouvrage dehayʾa,al-Tuḥfa al-shāhiyya, d'autres modèles inspirés de ceux d'al-Tūsī et d'al-ʿUrḍī, et produit un ensemble de nouveaux modèles pour Mercure et l'oscillation des sphères. Or, en dépit de tous ces efforts, la tradition des modèles non ptolémaïques, telle qu'elle se développa après lui, ne convergea pas vers un ensemble standard de modèles. (shrink)

This dissertation offers a new and comprehensive analysis of Abū Naṣr al-Fārābī's cosmology by focusing on various important issues that have been largely neglected by the modern scholarship. It provides an examination of the physical, metaphysical, and astronomical aspects of al-Fārābī's cosmology by adopting a multidisciplinary approach that takes into account the history of philosophy and the history of astronomy. Accordingly, my dissertation explores how al-Fārābī attempted to reconcile features of Ptolemaic astronomy with Aristotelian and Neoplatonic theories, an endeavor which (...) resulted in the formulation of innovative cosmological ideas. Chapters I and II provide background information on al-Fārābī's activity as a commentator and his relation to the Greek commentatorial tradition and assess the relevant primary sources. In addition, they examine al-Fārābī's approach to cosmology and his scientific method in terms of both the Ptolemaic astronomical tradition and the Aristotelian corpus. Chapter III addresses problems related to the structure of al-Fārābī's cosmology, especially the origin of his ennadic cosmological model and his spherology. Particular attention is devoted to the question of how Aristotle's unmoved movers and Ptolemy's astronomical theories are reconciled. Chapters IV, V, and VI analyze the place of celestial matter, intellect, and motion respectively in al-Fārābī's cosmology and attempt to redefine the second teacher's relation to the various trends of Greek philosophy. The study stresses al-Fārābī's connection with the Neoplatonic and Peripatetic currents, particularly with thinkers such as Alexander of Aphrod. (shrink)