AVEMPACE (Abu Bakr Muhammad ibn Yahya ibn as-Sa‘igh also called ibn Baggiah—physician, mathematician and astronomer, a renowned scholar and commentator on Aristotle’s writings on nature, b. around 1090 in Zaragoza, d. 1138 in Fèz (in Morroco).

Avempace was active in public life in Zaragoza, Fèz, Seville, and Granada. He held the title of vizier and served a prince of the Alvaraid dynasty. He is known as one of the first Aristotelians active in the Arab part of the Iberian Peninsula. He developed a method (known in the eastern Arab empire) for the systematic study of the philosophical texts called the Corpus Aristotelicum. In his commentaries on the texts of Aristotle he followed al-Farabi more than Avicenna. Besides commentaries in a neo-Platonic spirit on Aristotle’s writings (including commentaries on the Physics, On generation and corruption, Meteorology, and The movement of animals) he also wrote several philosophical treatises in logic and psychology, including Treatise on the unity of man with the active intellect—Risalah al ittisal (ed. Avempace sobre la unión del intelecto con el hombre, Al-Andalus 7 (1942), 1–47). His best known philosophical treatise, however, is a sort of spiritual guide to God (the active Intelligence) Tadbir al- mutawahhid (The hermit’s way of life, ed. El régimen del solitario, Ma 1946) on ethical problems concerning the differences between man’s actions and the behavior of beasts.

Avempace addressed the central problem of philosophy at the time and tried to establish the relation between rational individuals and the separate active intelligence. According to Avempace, a man may pass in succession from a knowledge of individual things to a knowledge of substance separate from matter. Man’s process of knowledge, which concludes in the order of abstraction, must end with the knowledge of an essence that no longer has in itself any matter, i.e., the essence of a separate substance. The human reason, by a gradual purification of the data of immediate sense experience, is able to acquire purely rational knowledge and arrive at a purely intellectual intuition of the world, uniting in this intuition with the active intellect, understood as an emanation of divinity. Yet the process of the human soul’s ascent to divinity does not have a mystical-ecstatic character for Avempace. It bears the mark only of intellectual self-perfection and the attainment of intellectual self-consciousness. At the same time, Avempace makes a clear division between science and philosophy on the one hand, and religion. At the same time he thinks that science and philosophy assure knowledge of the full truth about man and the world. In accordance with this conception of knowledge and Platonic and neo-Platonic inspirations, Avempace did not seek the true nature and cause of phenomena in immediate sense experience, but in abstract elements acquired by the reason from this experience. These epistemological-methodological conceptions led him in the philosophy of nature to the conclusion that we should not search for the laws that govern the motion of bodies in immediate sense experience, even though all observed bodies move in an environment that provides resistance. Rather we should search for these laws in experience conducted in idealized conditions, and then subjected to abstract analysis. He applied this method and corrected the laws of the motion of bodies formulated by Aristotle in the Book VII of the Physics (250 a–250 b) and established the relation of dependence: velocity (v) = force (f) - resistance (r). Although Avempace, in agreement with Aristotle, rejected the existence of a vacuum, he opposed Aristotle when he argued that even in a vacuum a body would move with a finite velocity, since even though there is no resistance in a vacuum, a body has a finite path to travel. Avempace’s ideas in dynamics may be considered as an attempt to unify the Aristotelian theory of motion by replacing the various kinds of causes of motion with one concept of force. Avempace tried to explain the motion of “heavy” bodies by analogy to magnetic phenomena rather than on the basis of the Aristotelian theory of natural places. At the same time he accepted the Aristotelian theory of coerced motion that presupposed that bodies can be moved by a coerced motion due to the influence of air, and he rejected conceptions that anticipated the ideas of the theory of impetus. In astronomy he rejected the theory of epicycles and said that they were in disagreement with Aristotle’s cosmology. He was one of the first to criticize Ptolemaic astronomy.

S. Munk, Mélanges de philosophie juive et arabe, P 1859, 349–409; E. A. Moody, Galileo and Avempace, Journal of the History of Ideas 12 (1951), 163–193, 375–422; A. C. Crombie, Medieval and Early Modern Science, GC 1959 (Nauka średniowieczne i początki nauki nowożytnej [Medieval science and the beginnings of modern science], Wwa 1960, II 72–73); S. Pines, La dynamique d’Ibn Bâjja, in: A. Koyré, L’aventure de la science, P 1964, 442–468; A. Goddu, Avicenna, Avempace, and Averroes: Arabic Sources of “Mutual Attraction” and Their Influence on Medieval and Modern Conceptions of Attraction and Gravitation, in: Orientalische Kultur und europäisches Mittelalter, B 1985, 218–239; L. Legowicz, Historia filozofii średniowiecznej [History of medieval philosophy], Wwa 1986, 68–69; Gilson HFS 198; P. Lettinck, Aristotle’s Physics and its Reception in the Arabic World, Lei 1994; idem, The Transformation of Aristotle’s Physical Philosophy in Ibn Baggia’s Commentaries, in: Tradition, Transmission, Transformation, Lei 1996, 65–70; idem, Ibn Bâggia as a Commentator of Aristotle, in: Perspectives arabes et médiévales sur la tradition scientifique et philosophique grecque, Lv 1997, 485–490.

Zenon E. Roskal

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