Abū-Bakr Muhammad ibn Yahya ibn al-Sāyigh
أبو بكر محمد بن يحيى بن الصائغ), known as Ibn Bājjah
(ابن باجة), was an Andalusian
: an astronomer
. He was known in the West by his Latinized name
. He was born in Zaragoza
in what is today Spain
and died in Fes, Morocco
in 1138. Avempace worked as vizir for Abu Bakr ibn Ibrahim Ibn Tîfilwît, the Almoravid
governor of Saragossa
. Avempace also wrote poems (panegyrics and 'muwasshahat') for him, and they both enjoyed music and wine. Avempace joined in poetic competitions with the poet al-Tutili
. He later worked, for some twenty years, as the vizir of Yahyà ibn Yûsuf Ibn Tashufin, another brother of the Almoravid
Sultan Yusuf Ibn Tashufin
(d. 1143) in Morocco.
His philosophic ideas had a clear effect on Ibn Rushd and Albertus Magnus.
Most of his writings and book were not completed (or well organized) because of his early death.
He had a vast knowledge of Medicine, Mathematics and Astronomy.
His main contribution to Islamic Philosophy is his idea on Soul Phenomenology, but unfortunately not completed.
His beloved expressions were Gharib غريب and Mutawahhid متوحد, two approved and popular expressions of Islamic Gnostics.
Ibn Bajjah was also a renowned poet. In his explanation of the Zajal E.G. Gomes writes: "There is some evidence for the belief that it was invented by the famous philosopher and musician known as Avempace. Its chief characteristic being that it is written entirely in the vernacular. ” (Emilio Gracia Gomes in his essay “Moorish Spain")
Though many of his works have not survived, his theories on astronomy and physics were preserved by Maimonides and Averroes respectively, which had a subsequent influence on later astronomers and physicists in the Islamic civilization and Renaissance Europe, including Galileo Galilei.
In Islamic astronomy
wrote the following on the planetary model proposed by Ibn Bajjah:
In his commentary on Aristotle's Meteorology, Ibn Bajjah presented his own theory on the Milky Way galaxy. Aristotle believed the Milky Way to be caused by "the ignition of the fiery exhalation of some stars which were large, numerous and close together" and that the "ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions." On the other hand, Aristotle's Arabic commentator Ibn al-Bitriq considered "the Milky Way to be a phenomenon exclusively of the heavenly spheres, not of the upper part of the atmosphere" and that the "light of those stars makes a visible patch because they are so close." Ibn Bajjah's view differed from both, as he considered "the Milky Way to be a phenomenon both of the spheres above the moon and of the sublunar region." The Stanford Encyclopedia of Philosophy describes his theory and observation on the Milky Way as follows:
In Islamic physics
, Ibn Bajjah's law of motion
was equivalent to the principle that uniform motion implies absence of action by a force
. This principle would later form the basis of modern mechanics
and have a subsequent influence on physicists such as Galileo Galilei
. Ibn Bajjah's definition of velocity
was also equivalent to Galileo's definition of velocity:
- Velocity = Motive Power - Material Resistance
where the motive power is measured by the specific gravity of the mobile body and the material resistance is the resisting medium whose resistive power is measured by its specific gravity.
Ibn Bajjah was also the first to state that there is always a reaction force for every force exerted, a precursor to Gottfried Leibniz's idea of force which underlies Newton's third law of motion or law of reciprocal actions.
Ibn Bajjah also had an influence on Thomas Aquinas' analysis of motion. In his Systeme du Monde, the pioneering historian of medieval science, Pierre Duhem, stated:
Text 71 of Averroes
' commentary on Aristotle
contains a discussion on Ibn Bajjah's theory of motion, as well as the following quotation from the seventh book of Ibn Bajjah's lost work on physics:
Averroes writes the following comments on Ibn Bajjah's theory of motion:
In Islamic psychology
, Ibn Bajjah "based his psychological studies on physics
." In his essay
, Recognition of the Active Intelligence
, he wrote that active intelligence
is the most important ability of human
beings, and he wrote many other essays on sensations
. He concluded that "knowledge
cannot be acquired by senses
alone but by Active Intelligence, which is the governing intelligence
of nature." He begins his discussion of the soul
with the definition that "bodies are composed of matter and form and intelligence is the most important part of man—sound knowledge is obtained through intelligence, which alone enables one to attain prosperity and build character." He viewed the unity of the rational
soul as the principle of the individual identity, and that by its contact with the Active Intelligence, it "becomes one of those lights that gives glory to God
." His definition of freedom
is "that when one can think and act rationally". He also writes that "the aim of life should be to seek spiritual
knowledge and make contact with Active Intelligence and thus with the Divine
- Marcinkowski, M. Ismail (April 2002), "A Biographical Note on Ibn Bajjah (Avempace) and an English Translation of his Annotations to al-Farabi's Isagoge", in Iqbal Review (Lahore, Pakistan), vol. 43, no. 2, pp. 83-99.
- The Diwan Attributed to Ibn Bajjah (Avempace),D. M. Dunlop, Bulletin of the School of Oriental and African Studies, University of London, Vol. 14, No. 3, Studies Presented to Vladimir Minorsky by His Colleagues and Friends (1952), pp. 463-477
- In Medieval Science, Technology, and Medicine: An Encyclopedia (2005). Routledge. ISBN 0415969301. .