| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 946-948 |
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Qūshjī: Abū
al‐Qāsim ʿAlāʾ al‐Dīn
ʿAlī ibn Muḥammad Qushči‐zāde
İhsan Fazlıoğlu
Born probably Samarqand,
(Uzbekistan)
Died Istanbul, (Turkey),
1474
ʿAlī al‐Qūshjī
was a philosopher–theologian, mathematician, astronomer, and linguist who
produced original studies in both observational and theoretical astronomy
within 15th‐century Islamic and Ottoman astronomy. He contributed to
the preparation of Ulugh Beg's
Zīj at the Samarqand Observatory, insisted on the possibility
of the Earth's motion, and asserted the need for the purification of all the
scientific disciplines from the principles of Aristotelian physics and metaphysics.
Qūshjī
was the son of Ulugh Beg's falconer, whence his Turkish name Qushči‐zāde.
He took courses in the linguistic sciences, mathematics, and astronomy as
well as other sciences taught by scholars in the circle of Ulugh Beg. These
included Jamshīd al‐Kāshī,
Qāḍīzāde al‐Rūmī,
and Ulugh Beg himself. It has been claimed that he was also taught by al‐Sayyid
al‐Sharīf al‐Jurjānī; if so, Qūshjī
would have been quite young.
In 1420,
Qūshjī secretly moved to Kirmān where he studied astronomy
(circa 1423‐1427) with Mollā Jāmī as well as the
mathematical sciences. Upon his return to Samarqand circa 1428, Qūshjī
presented Ulugh Beg with a monograph (Ḥall ishkāl al‐muʿaddil
li‐l‐masīr) in which he solved the
problems related to Mercury; Ulugh Beg was reported to have been quite pleased.
Sources say that Ulugh Beg referred to Qūshjī as “my virtuous son”
(= “ferzend‐i ercümend” [Nuruosmaniye MS 2932, f. 2b]). Indeed, after
the death of Qādīzāde, it was Qūshjī whom Ulugh Beg
commissioned to administer the observational work at the Samarqand Observatory
that was required for his Zīj (astronomical handbook). Qūshjī,
often referred to as “ṣāḥib‐i
raṣad” (head of observation), contributed
to the preparation and correction of the Zīj, but it is unclear
to what extent and at what stage. This question becomes especially problematic
in view of Qūshjī's criticisms of it, and his pointing out of mistakes,
in his Sharḥ‐i Zīj Ulugh Beg (Commentary on Ulugh Beg's
Zīj).
Upon Ulugh Beg's death in 1449, Qūshjī, together with his
family and students, spent a considerable time in Herat where he wrote his
theological work, Sharḥ
al‐Tajrīd, a commentary to Naṣīr
al‐Dīn al‐Ṭūsī's work al‐Tajrīd
fī ʿilm al‐kalām, which he presented to the Timurid Sultan Abū
Saʿīd. After
Abū Saʿīd's defeat
by Uzun Ḥasan
in 1469, Qūshjī moved to Tabrīz where he was welcomed by the
latter. It is said that Qūshjī was sent to Istanbul to settle a
dispute between Uzan Ḥasan and Mehmed the Conqueror; after accomplishing
the mission, he returned to Tabrīz. However, around 1472, Qūshī,
together with his family and students, left permanently for Istanbul either
on his own or because of an invitation from Sultan Mehmed.
When Qūshjī
and his entourage approached Istanbul, Sultan Mehmed sent a group of scholars
to welcome them. Sources say that in crossing the Bosporus to Istanbul, a
discussion ensued about the causes of its ebb and flow. Upon arrival in Istanbul,
Qūshjī presented his mathematical work entitled al‐Muḥammadiyya
fī al‐ḥisāb to the Sultan, which
was named in his honor.
Qūshjī
spent the remaining two to three years of his life in Istanbul. He first taught
in the Ṣaḥn‐i Thamān Madrasa
(founded by Sultan Mehmed); then he was made head of the Ayasofya Madrasa.
In this brief period, Qūshjī educated and influenced a large number
of students, who, along with his writings were to have an enormous impact
on future generations. He was buried in the cemetery of the Eyyūb mosque.
Qūshjī,
especially when compared with his contemporaries such as Kāshī and
Qāḍīzāde,
was a remarkable polymath who excelled in a variety of disciplines including
language and literature, philosophy, theology, mathematics, and astronomy.
He wrote works in all these fields, producing books, textbooks, and short
monographs dealing with specific problems. His commentaries often became more
popular than the original texts, and themselves became the subject of numerous
commentaries. Thousands of copies of Qūshjī's works are extant,
many of which were taught in the madrasas.
Qūshjī's
philosophy of science, which had important repercussions for the history of
astronomy, is contained in his commentary to Ṭūsī's Sharḥ al‐Tajrīd. Besides
being one of the most important theological works in Islam, Qūshjī
lays down the philosophical principles of his conception of existence, existents,
nature, knowledge, and language. As for the mathematical sciences, Qūshjī
in general tried to free them from hermetic–Pythagorean mysticism and to provide
an alternative to Aristotelian physics as the basis for astronomy and optics.
He sought to define body (jism) as being predominantly mathematical
in character. Qūshjī claimed that the essence of a body is composed
of discontinuous (atomic) quantity while its form consists of continuous (geometrical)
quantity. When a body is a subject of the senses, it then gains its natural
properties (qualifications).
One
consequence of Qūshjī's anti‐Aristotelian views was his striking
assertion that it might well be possible that the Earth is in motion. Here
Qūshjī followed a long line of Islamic astronomers who rejected
Ptolemy's
observational proofs for geostasis; Qūshji, though, refused to follow
them in depending on Aristotle's
philosophical proofs, thus opening up the possibility for a new physics in
which the Earth was in motion. Qūshjī's views were debated for centuries
after his death, and he exerted a profound influence on Ottoman–Turkish thought
and scientific inquiry, in particular through the madrasa and its curriculum.
His influence also extended to Central Asia and Iran, and it has been argued
that he may well have had an influence, either directly or indirectly, upon
early modern European science to which his ideas bear a striking resemblance.
Qūshjī
wrote five mathematics books, one in Persian and four in Arabic. His Risāla
dar ʿilm
al‐ḥisāb (Persian), written during
his stay in Central Asia (along with his enlarged Arabic version of this work,
al‐Risāla al‐Muḥammadiyya
fī al‐ḥisāb), were taught as a mid‐level
textbook in Ottoman madrasas. In these works, in accordance with the
principles he laid down in the Sharḥ
al‐Tajrīd, he tried to free mathematics from hermetic–Pythagorean
mysticism. As a result, Ottoman mathematics took on a practical character,
which hindered traditional studies such as the theory of numbers.
In the field of astronomy, one of Qūshjī's most important
contributions is in the observational program for the Zīj‐i
Ulugh Beg and in his corrections to the work, both before and after publication.
In addition, he has nine works on astronomy, two in Persian and seven in Arabic.
Some of them are original contributions while others are pedagogical. In his
theoretical monograph entitled Ḥall ishkāl al‐muʿaddil
li‐l‐masīr, Qūshjī criticizes
and corrects opinions and ideas pertaining to Mercury's motions mentioned
in Ptolemy's Almagest. Another work is his Risāla fī anna
aṣl al‐khārij yumkinu
fī al‐sufliyayn that deals with the possibility of using an
eccentric model for Mercury and Venus, which, as he says, goes against both
Ptolemy and Quṭb al‐Dīn al‐Shīrāzī.
Qūshjī's
Risāla dar ʿīlm
al‐hayʾa (Persian), written in Samarqand in 1458, was commonly
used as a teaching text; there exist over eighty manuscript copies of it in
libraries throughout the world. It was also translated into Turkish. Two commentaries
were written on it, one by Muṣliḥ al‐Dīn al‐Lārī,
the other by an anonymous author. Lārī's commentary was widely taught
in Ottoman madrasas. Qūshjī's Risāla was also
translated into Sanskrit and thus represents the transmission of Islamic astronomy
to the Indian subcontinent. Qūshjī wrote an enlarged version of
the work in Arabic under the name al‐Fatḥiyya
fī ʿilm
al‐hayʾa, which was presented to Sultan Mehmed in 1473. This
work was taught as a middle‐level textbook, and was commented on by
Gulām Sinān (died: 1506) and Qūshjī's famous mathematician‐astronomer
great‐grandson Mīram Čelebī.
It was also translated into Persian by Muʿīn
al‐Dīn al‐Ḥusaynī
and into Turkish by Seydî Ali Reîs. In the Risāla and the Fatḥiyya, Qūshjī followed
the principles he had laid down in his Sharḥ
al‐Tajrīd and excluded an introductory section on Aristotelian
physics that had customarily introduced almost all previous works of this
kind.
Selected References
Brockelmann, Carl. Geschichte der arabischen Litteratur.
2nd ed. Vol. 2 (1949): 305; Suppl. 2 (1938): 329–330. Leiden: E. J. Brill.
Fazlıoğlu, İhsan. “Ali Kusçu.” In Yasamları
ve Yapıtlarıyla Osmanlılar Ansiklopedisi, edited by Ekrem
Çakıroğlu. Vol. 1, pp. 216–219. Istanbul: YKY, 1999.
İhsanoğlu, Ekmeleddin et al. (1997). Osmanlı
Astronomi Literatürü Tarihi (OALT) (History of astronomy literature
during the Ottoman period). Vol. 1, pp. 27–38 (no. 11). Istanbul: IRCICA.
——— (1999). Osmanlı
Matematik Literatürü Tarihi (OMLT). (History of mathematical literature
during the Ottoman period). Vol. 1, pp. 20–27 (no. 3). Istanbul: IRCICA.
Pingree, David (1996). “Indian Reception of Muslim Versions
of Ptolemaic Astronomy.” In Tradition, Transmission, Transformation: Proceedings
of Two Conferences on Pre‐modern Science Held at the University of Oklahoma,
edited by F. Jamil Ragep and Sally P. Ragep, with Steven Livesey, pp. 471–485,
p. 474. Leiden: E. J. Brill.
Ragep, F. Jamil. (2001).
“Ṭūsī
and Copernicus: The Earth's Motion in Context.” Science in Context
14: 145–163.
——— (2001). “Freeing Astronomy from Philosophy: An Aspect of
Islamic Influence on Science.” Osiris 16: 49–71.
Saliba, George (1993). “Al‐Qūshjī's Reform of
the Ptolemaic Model for Mercury.” Arabic Sciences and Philosophy 3:
161–203.
Salih, Zeki (1329). Asar‐i bakiye. Vol. 1, pp.
195–199. Istanbul. (1913/1914): Matbaa‐i Amire.
Ṭashköprüzāde
(1985). Al‐Shaqāiʾq al‐nuʿmāniyya
fī ʿulamāʾ
al‐dawlat al‐ʿuthmāniyya, edited
by Ahmed Subhi Furat. Istanbul, pp. 159–162. Istanbul ūniversitesi, Edebiyat
Fakūltesi Yayinlave.
Ünver, A. Süheyl (1948). Astronom Ali Kusçu, Hayatı
ve Eserleri. Istanbul: Kenan Matbaası.