Muhammad ibn Muhammad ibn al-Hasan al-Tūsī ( fa, محمد ابن محمد ابن حسن طوسی 18 February 1201 – 26 June 1274), better known as Nasir al-Din al-Tusi ( fa, نصیر الدین طوسی, links=no; or simply Tusi in the West), was a
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
polymath
A polymath ( el, πολυμαθής, , "having learned much"; la, homo universalis, "universal human") is an individual whose knowledge spans a substantial number of subjects, known to draw on complex bodies of knowledge to solve specific pro ...
, architect,
philosopher
A philosopher is a person who practices or investigates philosophy. The term ''philosopher'' comes from the grc, φιλόσοφος, , translit=philosophos, meaning 'lover of wisdom'. The coining of the term has been attributed to the Greek th ...
,
physician
A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...
,
scientist
A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an Branches of science, area of the natural sciences.
In classical antiquity, there was no real ancient analog of a modern scientist. Instead, ...
, and
theologian
Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...
. Nasir al-Din al-Tusi was a well published author, writing on subjects of math, engineering, prose, and mysticism. Additionally, al-Tusi made several scientific advancements. In astronomy, al-Tusi created very accurate tables of
planetary motion
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a ...
, an updated planetary model, and critiques of
Ptolemaic astronomy
In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, an ...
. He also made strides in logic, mathematics but especially trigonometry, biology, and chemistry. Nasir al-Din al-Tusi left behind a great legacy as well. Tusi is widely regarded as one of the greatest scientists of medieval Islam, since he is often considered the creator of
trigonometry
Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. T ...
as a mathematical discipline in its own right. The Muslim scholar
Ibn Khaldun
Ibn Khaldun (; ar, أبو زيد عبد الرحمن بن محمد بن خلدون الحضرمي, ; 27 May 1332 – 17 March 1406, 732-808 AH) was an Arab
The Historical Muhammad', Irving M. Zeitlin, (Polity Press, 2007), p. 21; "It is, of ...
(1332–1406) considered Tusi to be the greatest of the later
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
scholars.
[James Winston Morris, "An Arab Machiavelli? Rhetoric, Philosophy and Politics in Ibn Khaldun’s Critique of Sufism", Harvard Middle Eastern and Islamic Review 8 (2009), pp 242–291]
excerpt from page 286 (footnote 39): "Ibn Khaldun’s own personal opinion is no doubt summarized in his pointed remark (Q 3: 274) that Tusi was better than any other later Iranian scholar". Original Arabic: Muqaddimat Ibn Khaldūn : dirāsah usūlīyah tārīkhīyah / li-Aḥmad Ṣubḥī Manṣūr-al-Qāhirah : Markaz Ibn Khaldūn : Dār al-Amīn, 1998. . Excerpt from Ibn Khaldun is found in the section: الفصل الثالث و الأربعون: في أن حملة العلم في الإسلام أكثرهم العجم (On how the majority who carried knowledge forward in Islam were Persians) In this section, see the sentence where he mentions Tusi as more knowledgeable than other later Persian ('Ajam) scholars: . و أما غيره من العجم فلم نر لهم من بعد الإمام ابن الخطيب و نصير الدين الطوسي كلاما يعول على نهايته في الإصابة. فاعتير ذلك و تأمله تر عجبا في أحوال الخليقة. و الله يخلق ما بشاء لا شريك له الملك و له الحمد و هو على كل شيء قدير و حسبنا الله و نعم الوكيل و الحمد لله. There is also reason to believe that he may have influenced
Copernican heliocentrism
Copernican heliocentrism is the astronomical model developed by Nicolaus Copernicus and published in 1543. This model positioned the Sun at the center of the Universe, motionless, with Earth and the other planets orbiting around it in circular pa ...
.
Nasir proposed that humans are related to animals and that some animals have a limited level of awareness while humans have a superior level of awareness amongst animals. He also framed a very basic evolutionary theory (though markedly different from modern evolutionary theory).
Biography
Nasir al-Din al-Tusi was born in the city of
Tus
Tus or TUS may refer to:
* Tus (biology), a protein that binds to terminator sequences
* Thales Underwater Systems, an international defence contractor
* Tuscarora language, an Iroquoian language, ISO 639-3 code
Education
* Technological Univ ...
in medieval
Khorasan
Khorasan may refer to:
* Greater Khorasan, a historical region which lies mostly in modern-day northern/northwestern Afghanistan, northeastern Iran, southern Turkmenistan, Tajikistan, and Uzbekistan
* Khorasan Province, a pre-2004 province of Ira ...
(northeastern
Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
) in the year 1201 and began his studies at an early age. In Hamadan and Tus he studied the
Quran
The Quran (, ; Standard Arabic: , Classical Arabic, Quranic Arabic: , , 'the recitation'), also romanized Qur'an or Koran, is the central religious text of Islam, believed by Muslims to be a revelation in Islam, revelation from God in Islam, ...
,
hadith
Ḥadīth ( or ; ar, حديث, , , , , , , literally "talk" or "discourse") or Athar ( ar, أثر, , literally "remnant"/"effect") refers to what the majority of Muslims believe to be a record of the words, actions, and the silent approval ...
,
Ja'fari jurisprudence, logic, philosophy, mathematics, medicine, and astronomy.
[Dabashi, Hamid. "Khwajah Nasir al-Din Tusi: The philosopher/vizier and the intellectual climate of his times". Routledge History of World Philosophies. Vol I. History of Islamic Philosophy. Seyyed Hossein Nasr and Oliver Leaman (eds.) London: Routledge. 1996. p. 529]
He was born into a Shī‘ah family and lost his father at a young age. Fulfilling the wish of his father, the young Muhammad took learning and scholarship very seriously and traveled far and wide to attend the lectures of renowned scholars and acquired knowledge, an exercise highly encouraged in his Islamic faith. At a young age, he moved to
Nishapur
Nishapur or officially Romanized as Neyshabur ( fa, ;Or also "نیشاپور" which is closer to its original and historic meaning though it is less commonly used by modern native Persian speakers. In Persian poetry, the name of this city is wr ...
to study philosophy under Farid al-Din Damad and mathematics under
Muhammad Hasib.
[Siddiqi, Bakhtyar Husain. "Nasir al-Din Tusi". A History of Islamic Philosophy. Vol 1. M. M. Sharif (ed.). Wiesbaden:: Otto Harrossowitz. 1963. p. 565] He met also
Attar of Nishapur
Abū Ḥamīd bin Abū Bakr Ibrāhīm (c. 1145 – c. 1221; fa, ابو حامد بن ابوبکر ابراهیم), better known by his pen-names Farīd ud-Dīn () and ʿAṭṭār of Nishapur (, Attar means apothecary), was a PersianRitter, H. ( ...
, the legendary
Sufi master who was later killed by the
Mongols
The Mongols ( mn, Монголчууд, , , ; ; russian: Монголы) are an East Asian ethnic group native to Mongolia, Inner Mongolia in China and the Buryatia Republic of the Russian Federation. The Mongols are the principal membe ...
, and he attended the lectures of
Qutb al-Din al-Misri
Qutb, Qutub, Kutb, Kutub or Kotb ( ar, قطب), means 'axis', 'pivot' or 'pole'. Qutb can refer to celestial movements and be used as an astronomical term or a spiritual symbol. In Sufism, a Qutb is the perfect human being, ''al-Insān al-Kā ...
.
Nasir-al-Din Tusi writes in his work, ''Desideratum of the Faithful (Maṭlūb al-muʾminīn)'',“To become people of spiritual reality, it is incumbent to fulfill the symbolic elucidation (''
ta'wīl'') of the seven pillars of the religious law (''
sharīʿat'')”. He also explains that fulfilling the religious law is much easier than fulfilling its spiritual interpretation.
He explains in his book ''Aghaz u anjam'' that the sacred accounts of history that we perceive within the bounds of space and time symbolize events that have no such restrictions. They are only expressed in this way so that humans are able to comprehend them.
In
Mosul
Mosul ( ar, الموصل, al-Mawṣil, ku, مووسڵ, translit=Mûsil, Turkish: ''Musul'', syr, ܡܘܨܠ, Māwṣil) is a major city in northern Iraq, serving as the capital of Nineveh Governorate. The city is considered the second large ...
, al-Tusi studied mathematics and astronomy with
Kamal al-Din Yunus (d.
AH 639 / AD 1242), a pupil of
Sharaf al-Dīn al-Ṭūsī
Sharaf al-Dīn al-Muẓaffar ibn Muḥammad ibn al-Muẓaffar al-Ṭūsī ( fa, شرفالدین مظفر بن محمد بن مظفر توسی; 1135 – 1213) was an Iranian mathematician and astronomer of the Islamic Golden Age (during the ...
.
Later on he corresponded with
Sadr al-Din al-Qunawi
Ṣadr al-Dīn Muḥammad ibn Isḥāq ibn Muḥammad ibn Yūnus Qūnawī lternatively, Qūnavī, Qūnyawī ( fa, صدر الدین قونوی; 1207–1274), was a PersianF. E. Peters, "The Monotheists", Published by Princeton University Press ...
, the son-in-law of
Ibn Arabi
Ibn ʿArabī ( ar, ابن عربي, ; full name: , ; 1165–1240), nicknamed al-Qushayrī (, ) and Sulṭān al-ʿĀrifīn (, , 'Sultan of the Knowers'), was an Arab Andalusian Muslim scholar, mystic, poet, and philosopher, extremely influenti ...
, and it seems that mysticism, as propagated by Sufi masters of his time, was not appealing to him. Once the occasion was suitable, he composed his own manual of philosophical Sufism in the form of a small booklet entitled ''Awsaf al-Ashraf,'' or "The Attributes of the Illustrious".
As the armies of
Genghis Khan
''Chinggis Khaan'' ͡ʃʰiŋɡɪs xaːŋbr />Mongol script: ''Chinggis Qa(gh)an/ Chinggis Khagan''
, birth_name = Temüjin
, successor = Tolui (as regent)Ögedei Khan
, spouse =
, issue =
, house = Borjigin
, ...
swept his homeland, he was employed by the
Nizari Ismaili state
The Nizari state (the Alamut state) was a Shia Nizari Ismaili state founded by Hassan-i Sabbah after he took control of the Alamut Castle in 1090 AD, which marked the beginning of an era of Ismailism known as the "Alamut period". Their people w ...
and, while moving from stronghold to stronghold, made his most important contributions in science, first in those of the
Quhistan
Quhistan ( fa, قهستان) or Kohistan (, "mountainous land") was a region of medieval Persia, essentially the southern part of Khurasan. Its boundaries appear to have been south of Khorasan to north, Yazd to West, Sistan to South, Afghanistan to ...
region under
Muhtasham Nasir al-Din Abd al-Rahim ibn Abi Mansur (where he wrote the ''
Nasirean Ethics''). He was later sent to the major castles of
Alamut
Alamut ( fa, الموت) is a region in Iran including western and eastern parts in the western edge of the Alborz (Elburz) range, between the dry and barren plain of Qazvin in the south and the densely forested slopes of the Mazandaran provinc ...
and
Maymun-Diz
Maymūn-Diz ( fa, میمون دز) was a major fortress of the Nizari Ismailis of the Alamut Period described in historical records. It has been variously identified with the Alamut Castle, Navizar Shah Castle, Shirkuh Castle, Shahrak Castle, ...
to continue his career under Nizari Imam
Ala al-Din Muhammad. He was captured after the fall of Maymun-Diz to the Mongol forces under
Hulagu Khan
Hulagu Khan, also known as Hülegü or Hulegu ( mn, Хүлэгү/ , lit=Surplus, translit=Hu’legu’/Qülegü; chg, ; Arabic: fa, هولاکو خان, ''Holâku Khân;'' ; 8 February 1265), was a Mongol ruler who conquered much of West ...
.
Nasir al-Din Tusi’s autobiography, ''The Voyage (Sayr wa-Suluk)'' explains that a literary devastation such as the devastation of the
Alamūt libraries in 1256 would not waver the spirit of the
Nizari Ismaili
The Nizaris ( ar, النزاريون, al-Nizāriyyūn, fa, نزاریان, Nezāriyān) are the largest segment of the Ismaili Muslims, who are the second-largest branch of Shia Islam after the Twelvers. Nizari teachings emphasize independent ...
community because they give more importance to the “living book” (the
Imam of the Time) rather than the “
written word
Writing is a medium of human communication which involves the representation of a language through a system of physically Epigraphy, inscribed, Printing press, mechanically transferred, or Word processor, digitally represented Symbols (semiot ...
”. Their hearts are attached to the Commander of the Believers (''
amir al-mu'minin
Amir al-Mu'minin ( ar, أَمِير ٱلْمُؤْمِنِين, amīr al-muʾminīn) is an Arabic title designating the supreme leader of an Islamic community. It is usually translated as "Commander of the Faithful", though sometimes also as "Prin ...
''), not just the “
command
Command may refer to:
Computing
* Command (computing), a statement in a computer language
* COMMAND.COM, the default operating system shell and command-line interpreter for DOS
* Command key, a modifier key on Apple Macintosh computer keyboards
* ...
” itself. There is always a present living
Imam
Imam (; ar, إمام '; plural: ') is an Islamic leadership position. For Sunni Muslims, Imam is most commonly used as the title of a worship leader of a mosque. In this context, imams may lead Islamic worship services, lead prayers, ser ...
in world, and following him, a believer will never go astray.
Role during the Mongol invasion of Baghdad
In 1256 al-Tusi was in the castle of Alamut when it was attacked by the forces of the Mongol leader Hulegu, a grandson of Genghis Khan. Some sources claim that al-Tusi betrayed the defences of Alamut to the invading Mongols. After Hulegu's forces destroyed Alamut and,
Hulegu
Hulagu Khan, also known as Hülegü or Hulegu ( mn, Хүлэгү/ , lit=Surplus, translit=Hu’legu’/Qülegü; chg, ; Arabic: fa, هولاکو خان, ''Holâku Khân;'' ; 8 February 1265), was a Mongol ruler who conquered much of West ...
himself being interested in the natural sciences, treated al-Tusi with great respect, appointing him as their scientific adviser and becoming a permanent member of his inner council. To great controversy, it is widely assumed Tusi was with the Mongol forces under Hulegu when they attacked and massacred the inhabitants of Baghdad in 1258.
Soon after, he was given the full authority of administering the finances of religious foundations, and visited many of the Shi'ii shrines once the siege of Baghdad was over.
Being in a position of power, Tusi was able to champion the Twelver Shia cause throughout Persia and Iraq.
Works
Tusi has about 150 works, of which 25 are in
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
and the remaining are in
Arabic
Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
,
and there is one treatise in Persian, Arabic and
Turkish.
* ''Sayr wa-Suluk (The Voyage)'' - Autobiography
* ''Kitāb al-Shakl al-qattāʴ'' Book on the complete quadrilateral. A five-volume summary of trigonometry.
* ''Al-Tadhkirah fi'ilm al-hay'ah'' – A memoir on the science of astronomy. Many commentaries were written about this work called Sharh al-Tadhkirah (A Commentary on al-Tadhkirah) - Commentaries were written by
Abd al-Ali ibn Muhammad ibn al-Husayn al-Birjandi and by
Nazzam Nishapuri.
* ''
Akhlaq-i Nasiri
''Nasirean Ethics'' ( fa, اخلاق ناصری ''Akhlāq-i Nāsirī'') is a 13th century Persian book in philosophical ethics that is written by Khaje Nasir al-Din al-Tusi. This book is divided to three part: ethics, domestic economy and politic ...
'' – A work on ethics.
* ''al-Risalah al-Asturlabiyah'' – A Treatise on the astrolabe.
* ''
Zij-i Ilkhani'' (''Ilkhanic Tables'') – A major astronomical treatise, completed in 1272.
* ''
Sharh al-Isharat Sharh al-Isharat () is a philosophical commentary on Avicenna's book ''Al-isharat wa al-tanbihat'' (''Remarks and Admonitions''). This commentary has been written by Nasir al-Din al-Tusi in defense of the philosophy of Avicenna in response to the cr ...
'' (''Commentary on Avicenna's Isharat'')
* ''
Awsaf al-Ashraf'' a short mystical-ethical work in Persian.
* ''
Tajrīd al-Iʿtiqād Tajrīd al-iʿtiqād (عربی: تجرید الاعتقاد) or Tajrid al-Kalam is a work by Nasir al-Din al-Tusi about Shia beliefs in Islamic theology. Tajrid is the most famous scholastic text in Shiite theology and most effective work in histor ...
'' (Summation of Belief) – A commentary on Shia doctrines.
* ''
Talkhis al-Muhassal'' (summary of summaries).
* ''Maṭlūb al-muʾminīn'' (Desideratum of the Faithful)
* ''Aghaz u anjam -'' Esoteric interpretation of the Quran
An example from one of his poems:
Anyone who knows, and knows that he knows,
makes the steed of intelligence leap over the vault of heaven.
Anyone who does not know but knows that he does not know,
can bring his lame little donkey to the destination nonetheless.
Anyone who does not know, and does not know that he does not know,
is stuck forever in double ignorance.
Achievements
During his stay in Nishapur, Tusi established a reputation as an exceptional scholar. Tusi’s prose writing, which numbers over 150 works, represent one of the largest collections by a single Islamic author. Writing in both
Arabic
Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
and
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
, Nasir al-Din Tusi dealt with both religious ("Islamic") topics and non-religious or secular subjects ("the ancient sciences").
[H. Daiber, F.J. Ragep, "Tusi" in Encyclopaedia of Islam. Edited by: P. Bearman, Th. Bianquis, C.E. Bosworth, E. van Donzel and W.P. Heinrichs. Brill, 2007. Brill Online. Quote: "Tusi's prose writings, which number over 150 works, represent one of the largest collections by a single Islamic author. Writing in both Arabic and Persian, Nasir al-Din dealt with both religious ("Islamic") topics and non-religious or secular subjects ("the ancient sciences")."] His works include the definitive Arabic versions of the works of
Euclid
Euclid (; grc-gre, Wikt:Εὐκλείδης, Εὐκλείδης; BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the ''Euclid's Elements, Elements'' trea ...
,
Archimedes
Archimedes of Syracuse (;; ) was a Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily. Although few details of his life are known, he is regarded as one of the leading scientists ...
,
Ptolemy
Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
,
Autolycus, and
Theodosius of Bithynia
Theodosius of Bithynia ( grc-gre, Θεοδόσιος; c. 169 BCc. 100 BC) was a Greek astronomer and mathematician who wrote the ''Sphaerics'', a book on the geometry of the sphere.
Life
Born in Tripolis, in Bithynia, Theodosius was m ...
.
Astronomy
Tusi convinced
Hulegu Khan to construct an observatory for establishing accurate astronomical tables for better astrological predictions. Beginning in 1259, the
Rasad Khaneh observatory was constructed in
Azarbaijan
Azerbaijan or Azarbaijan ( fa, آذربایجان, ''Āzarbāijān'' ; az-Arab, آذربایجان, ''Āzerbāyjān'' ), also known as Iranian Azerbaijan, is a historical region in northwestern Iran that borders Iraq, Turkey, the Nakhchivan ...
, south of the river
Aras, and to the west of
Maragheh
Maragheh ( fa, مراغه, Marāgheh or ''Marāgha''; az, ماراغا ) is a city and capital of Maragheh County, East Azerbaijan Province, Iran. Maragheh is on the bank of the river Sufi Chay. The population consists mostly of Iranian Azerba ...
, the capital of the
Ilkhanate Empire.
Based on the observations in this for the time being most advanced observatory, Tusi made very accurate tables of
planetary movements as depicted in his book ''
Zij-i ilkhani'' (''Ilkhanic Tables''). This book contains astronomical tables for calculating the positions of the planets and the names of the stars. His model for the planetary system is believed to be the most advanced of his time, and was used extensively until the development of the heliocentric model in the time of
Nicolaus Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic Church, Catholic cano ...
. Between
Ptolemy
Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
and
Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic canon, who formulated ...
, he is considered by many to be one of the most eminent astronomers of his time. His famous student
Shams al-Din al-Bukhari Shams ( ar, شمس , links=no), an Arabic word meaning ''sun'', may refer to:
Media
* ''Shams'' (newspaper), a defunct Saudi newspaper
* ''Al-Shams'' (newspaper), a Libyan government newspaper until 2011
* Network for Public Policy Studies, an ...
was the teacher of
Byzantine
The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinopl ...
scholar
Gregory Chioniades
Gregory Chioniades ( el, Γρηγόριος Χιονιάδης, Grēgorios Chioniadēs; c. 1240 – c. 1320) was a Byzantine Greek astronomer. He traveled to Persia, where he learned Persian mathematical and astronomical science, which he introduce ...
,
who had in turn trained
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
Manuel Bryennios Manuel Bryennios or Bryennius ( el, Μανουήλ Βρυέννιος; c. 1275 – c. 1340). was a Byzantine scholar who flourished in Constantinople about 1300 teaching astronomy, mathematics and musical theory.. His only surviving work is the ''H ...
about 1300 in
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis (" ...
.
For his planetary models, he invented a geometrical technique called a
Tusi-couple
The Tusi couple is a mathematical device in which a small circle rotates inside a larger circle twice the diameter of the smaller circle. Rotations of the circles cause a point on the circumference of the smaller circle to oscillate back and fort ...
, which generates linear motion from the sum of two circular motions. He used this technique to replace
Ptolemy
Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
's problematic
equant
Equant (or punctum aequans) is a mathematical concept developed by Claudius Ptolemy in the 2nd century AD to account for the observed motion of the planets. The equant is used to explain the observed speed change in different stages of the plane ...
for many planets, but was unable to find a solution to Mercury, which was solved later by
Ibn al-Shatir
ʿAbu al-Ḥasan Alāʾ al‐Dīn ʿAlī ibn Ibrāhīm al-Ansari known as Ibn al-Shatir or Ibn ash-Shatir ( ar, ابن الشاطر; 1304–1375) was an Arab astronomer, mathematician and engineer. He worked as '' muwaqqit'' (موقت, religious ...
as well as
Ali Qushji
Ala al-Dīn Ali ibn Muhammed (1403 – 16 December 1474), known as Ali Qushji (Ottoman Turkish : علی قوشچی, ''kuşçu'' – falconer in Turkish; Latin: ''Ali Kushgii'') was a Timurid theologian, jurist, astronomer, mathematician a ...
. The Tusi couple was later employed in
Ibn al-Shatir
ʿAbu al-Ḥasan Alāʾ al‐Dīn ʿAlī ibn Ibrāhīm al-Ansari known as Ibn al-Shatir or Ibn ash-Shatir ( ar, ابن الشاطر; 1304–1375) was an Arab astronomer, mathematician and engineer. He worked as '' muwaqqit'' (موقت, religious ...
's
geocentric model
In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, an ...
and
Nicolaus Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic Church, Catholic cano ...
'
heliocentric
Heliocentrism (also known as the Heliocentric model) is the astronomical model in which the Earth and planets revolve around the Sun at the center of the universe. Historically, heliocentrism was opposed to geocentrism, which placed the Earth at ...
Copernican model
Copernican heliocentrism is the astronomical model developed by Nicolaus Copernicus and published in 1543. This model positioned the Sun at the center of the Universe, motionless, with Earth and the other planets orbiting around it in circular pa ...
. He also calculated the value for the annual precession of the
equinox
A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" and se ...
es and contributed to the construction and usage of some astronomical instruments including the
astrolabe
An astrolabe ( grc, ἀστρολάβος ; ar, ٱلأَسْطُرلاب ; persian, ستارهیاب ) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclin ...
.
Ṭūsī criticized Ptolemy's use of observational evidence to show that the Earth was at rest, noting that such proofs were not decisive. Although it doesn't mean that he was a supporter of mobility of the earth, as he and his 16th-century commentator
al-Bīrjandī, maintained that the earth's immobility could be demonstrated, only by physical principles found in natural philosophy. Tusi's criticisms of Ptolemy were similar to the arguments later used by Copernicus in 1543 to defend the Earth's rotation.
About the real essence of the Milky Way, Ṭūsī in his ''Tadhkira'' writes:
"The Milky Way, i.e. the galaxy, is made up of a very large number of small, tightly-clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches. because of this, it was likened to milk in color."
Three centuries later the proof of the Milky Way consisting of many stars came in 1610 when
Galileo Galilei
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He was ...
used a
telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
to study the Milky Way and discovered that it is really composed of a huge number of faint stars.
Logic
Nasir al-Din Tusi was a supporter of
Avicennian logic, and wrote the following commentary on
Avicenna
Ibn Sina ( fa, ابن سینا; 980 – June 1037 CE), commonly known in the West as Avicenna (), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, philosophers, and writers of the Islamic G ...
's theory of absolute
proposition
In logic and linguistics, a proposition is the meaning of a declarative sentence. In philosophy, " meaning" is understood to be a non-linguistic entity which is shared by all sentences with the same meaning. Equivalently, a proposition is the no ...
s:
Mathematics
Al-Tusi was the first to write a work on trigonometry independently of astronomy.
Al-Tusi, in his ''Treatise on the Quadrilateral'', gave an extensive exposition of
spherical trigonometry
Spherical trigonometry is the branch of spherical geometry that deals with the metrical relationships between the sides and angles of spherical triangles, traditionally expressed using trigonometric functions. On the sphere, geodesics are gr ...
, distinct from astronomy. It was in the works of Al-Tusi that trigonometry achieved the status of an independent branch of pure mathematics distinct from astronomy, to which it had been linked for so long.
He was the first to list the six distinct cases of a right triangle in spherical trigonometry.
This followed earlier work by
Greek mathematicians
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
such as
Menelaus of Alexandria
Menelaus of Alexandria (; grc-gre, Μενέλαος ὁ Ἀλεξανδρεύς, ''Menelaos ho Alexandreus''; c. 70 – 140 CE) was a GreekEncyclopædia Britannica "Greek mathematician and astronomer who first conceived and defined a spheric ...
, who wrote a book on spherical trigonometry called ''Sphaerica,'' and the earlier Muslim mathematicians
Abū al-Wafā' al-Būzjānī
Abū al-Wafāʾ Muḥammad ibn Muḥammad ibn Yaḥyā ibn Ismāʿīl ibn al-ʿAbbās al-Būzjānī or Abū al-Wafā Būzhjānī ( fa, ابوالوفا بوزجانی or بوژگانی) (10 June 940 – 15 July 998) was a Persian mathematician a ...
and
Al-Jayyani
Abū ʿAbd Allāh Muḥammad ibn Muʿādh al-Jayyānī ( ar, أبو عبد الله محمد بن معاذ الجياني; 989, Cordova, Al-Andalus – 1079, Jaén, Al-Andalus) was an Arab, mathematician, Islamic scholar, and Qadi from Al-Anda ...
.
In his ''On the Sector Figure'', appears the famous
Sine Law for plane triangles.
:
He also stated the sine law for spherical triangles, discovered the
law of tangents
In trigonometry, the law of tangents is a statement about the relationship between the tangents of two angles of a triangle and the lengths of the opposing sides.
In Figure 1, , , and are the lengths of the three sides of the triangle, and , , ...
for spherical triangles, and provided proofs for these laws.
[
]
Color theory
While Aristotle (d. 322 BCE) had suggested that all colors can be aligned on a single line from black to white, Ibn-Sina (d. 1037) described that there were three paths from black to white, one path via grey, a second path via red and the third path via green. Al-Tusi (ca. 1258) stated that there are no less than five of such paths, via lemon (yellow), blood (red), pistachio (green), indigo (blue) and grey. This text, which was copied in the Middle East numerous times until at least the nineteenth century as part of the textbook Revision of the Optics (Tanqih al-Manazir) by Kamal al-Din al-Farisi (d. 1320), made color space effectively two-dimensional.
Robert Grosseteste (d. 1253) proposed an effectively three-dimensional model of color space.
Biology
In his ''Akhlaq-i Nasiri'', Tusi wrote about several biological topics. He defended a version of Aristotle's ''scala naturae
The great chain of being is a hierarchical structure of all matter and life, thought by medieval Christianity to have been decreed by God. The chain begins with God and descends through angels, humans, animals and plants to minerals.
The great c ...
'', in which he placed man above animals, plants, minerals, and the elements. He described "grasses which grow without sowing or cultivation, by the mere mingling of elements,"[Nasir ad-Din Tusi (1964) ''The Nasirean Ethics'' (translator: G.M. Wickens). London: Allen & Unwin, p. 44.] as closest to minerals. Among plants, he considered the date-palm as the most highly developed, since "it only lacks one thing further to reach (the stage of) an animal: to tear itself loose from the soil and to move away in the quest for nourishment."
The lowest animals "are adjacent to the region of plants: such are those animals which propagate like grass, being incapable of mating .. e.g. earthworm
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...
s, and certain insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s". The animals "which reach the stage of perfection ..are distinguished by fully developed weapons", such as antlers, horns, teeth, and claws. Tusi described these organs as adaptations to each species's lifestyle, in a way anticipating natural theology
Natural theology, once also termed physico-theology, is a type of theology that seeks to provide arguments for theological topics (such as the existence of a deity) based on reason and the discoveries of science.
This distinguishes it from ...
. He continued:
Thus, in this paragraph, Tusi described different types of learning
Learning is the process of acquiring new understanding, knowledge, behaviors, skills, value (personal and cultural), values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machine learning, machines ...
, recognising observational learning
Observational learning is learning that occurs through observing the behavior of others. It is a form of social learning which takes various forms, based on various processes. In humans, this form of learning seems to not need reinforcement to oc ...
as the most advanced form, and correctly attributing it to certain animals.
Tusi seems to have perceived man as belonging to the animals, since he stated that "the Animal Soul omprising the faculties of perception and movement ...is restricted to individuals of the animal species", and that, by possessing a "Human Soul, ..mankind is distinguished and particularized among ''other'' animals."
Some scholars have interpreted Tusi's biological writings as suggesting that he adhered to some kind of evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
ary theory. However, Tusi did not state explicitly that he believed species to change over time.
Chemistry
Tusi contributed to the field of chemistry, stating an early law of conservation of mass
In physics and chemistry, the law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass can ...
.
Philosophy
Tusi contributed many writings to the topic of philosophy. Amongst his philosophical work are his disagreements with fellow philosopher Avicenna
Ibn Sina ( fa, ابن سینا; 980 – June 1037 CE), commonly known in the West as Avicenna (), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, philosophers, and writers of the Islamic G ...
. His most famous philosophical work is ''Akhlaq-i nasiri
''Nasirean Ethics'' ( fa, اخلاق ناصری ''Akhlāq-i Nāsirī'') is a 13th century Persian book in philosophical ethics that is written by Khaje Nasir al-Din al-Tusi. This book is divided to three part: ethics, domestic economy and politic ...
'' or '' Nasirean Ethics'' in English. Within this work he discusses and compares Islamic teachings to the ethics of Aristotle and Plato. Tusi's book became a popular ethical work in the Muslim world, specifically in India and Persia. Tusi's work also left an impact on Shi'ite Islamic theology. His book ''Targid'' also called ''Catharsis'' is significant in Shi'ite theology. He also contributed five works to the subject of logic; which were highly regarded by his contemporaries and achieved notoriety in the Muslim world.
Influence and legacy
A 60-km diameter lunar crater located on the southern hemisphere of the moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
is named after him as " Nasireddin". A minor planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
10269 Tusi discovered by Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
astronomer Nikolai Stepanovich Chernykh in 1979 is named after him. The K. N. Toosi University of Technology in Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
and Observatory of Shamakhy in the Republic of Azerbaijan
A republic () is a "state in which power rests with the people or their representatives; specifically a state without a monarchy" and also a "government, or system of government, of such a state." Previously, especially in the 17th and 18th ...
are also named after him. In February 2013, Google celebrated his 812th birthday with a doodle
A doodle is a drawing made while a person's attention is otherwise occupied. Doodles are simple drawings that can have concrete representational meaning or may just be composed of random and abstract lines or shapes, generally without ever lift ...
, which was accessible in its websites with Arabic language calling him ''al-farsi'' (the Persian). His birthday is also celebrated as Engineer's Day
Engineer's Day is observed in several countries on various dates of the year.
On 25 November 2019, based on a proposal by the World Federation of Engineering Organizations (WFEO), UNESCO has proclaimed March 4 as 'UNESCO World Engineering Day for ...
in Iran.
Possible Influence on Nicolaus Copernicus
Some scholars believe that Nicolaus Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic Church, Catholic cano ...
may have been influenced by Middle Eastern astronomers due to uncanny similarities between his work and the uncited work of these Islamic scholars, including Nasir al-Din al-Tusi, Ibn al-Shatir
ʿAbu al-Ḥasan Alāʾ al‐Dīn ʿAlī ibn Ibrāhīm al-Ansari known as Ibn al-Shatir or Ibn ash-Shatir ( ar, ابن الشاطر; 1304–1375) was an Arab astronomer, mathematician and engineer. He worked as '' muwaqqit'' (موقت, religious ...
, Muayyad al-Din al-Urdi, and Qutb al-Din al-Shirazi
Qotb al-Din Mahmoud b. Zia al-Din Mas'ud b. Mosleh Shirazi (1236–1311) ( fa, قطبالدین محمود بن ضیاالدین مسعود بن مصلح شیرازی) was a 13th-century Persian polymath and poet who made contributions to a ...
. al-Tusi specifically, the plagiarism in question comes from similarities in the Tusi couple
The Tusi couple is a mathematical device in which a small circle rotates inside a larger circle twice the diameter of the smaller circle. Rotations of the circles cause a point on the circumference of the smaller circle to oscillate back and fort ...
and Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic canon, who formulated ...
' geometric method of removing the Equant
Equant (or punctum aequans) is a mathematical concept developed by Claudius Ptolemy in the 2nd century AD to account for the observed motion of the planets. The equant is used to explain the observed speed change in different stages of the plane ...
from mathematical astronomy. Not only do both of the methods match geometrically, however, more importantly they both use the same exact lettering system for each vertex
Vertex, vertices or vertexes may refer to:
Science and technology Mathematics and computer science
*Vertex (geometry), a point where two or more curves, lines, or edges meet
* Vertex (computer graphics), a data structure that describes the positio ...
; a detail that seems too preternatural to be happenstance. Moreover, the fact that several other details of his model also mirror other Islamic scholars bolsters the notion that Copernicus' work may not have been only his own.
There is no evidence that any of the direct work of Nasir al-Din al-Tusi ever made it to Copernicus, however there is evidence that the mathematics and theories did make the journey to Europe. There were Jewish scientists and pilgrims who would make the journey from the Middle East to Europe, bringing with them Middle Eastern scientific ideas to share with their Christian counterparts. While acknowledging that this is not direct evidence that Copernicus has access to al-Tusi's work, it does show that it was possible. There was just such a Jewish scholar by the name of Abner of Burgos
Abner of Burgos (c. 1270 – c. 1347, or a little later) was a Jewish philosopher, a convert to Christianity and polemical writer against his former religion. Known after his conversion as Alfonso of Valladolid.
Life
As a student he acquired a ce ...
who wrote a book containing an incomplete version of the Tusi couple that he had learned second hand, which could have been found by Copernicus. It is important to note that his version had no proofs of the geometry either, so if Copernicus had obtained this book he would have had to complete both the proof and mechanism. Additionally, some scholars believe that, if not Jewish thinkers, it could have been transmission from the Islamic school in Maragheh
Maragheh ( fa, مراغه, Marāgheh or ''Marāgha''; az, ماراغا ) is a city and capital of Maragheh County, East Azerbaijan Province, Iran. Maragheh is on the bank of the river Sufi Chay. The population consists mostly of Iranian Azerba ...
, home to Nasir al-Din al-Tusi's observatory
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. His ...
to Muslim Spain. From Spain, al-Tusi and other Islamic cosmological theories could spread through Europe. Spread of Islamic astronomy from Maragheh Observatory into Europe could have also been possible in the form of Greek translations from Gregory Choniades
Gregory Chioniades ( el, Γρηγόριος Χιονιάδης, Grēgorios Chioniadēs; c. 1240 – c. 1320) was a Byzantine Greek astronomer. He traveled to Persia, where he learned Persian mathematical and astronomical science, which he introduce ...
. There is evidence as to the means of Copernicus acquiring the Tusi couple and suspicious similarities, not only in math but in visual details as well.
Despite this circumstantial evidence, there is still no direct proof that Copernicus did plagiarize the work of Nasir al-Din al-Tusi, and if he did that he did so intentionally. The Tusi couple is not a unique principle, and as the equant was a problematic necessity to preserve circular motion it is possible that more than one astronomer wished to improve on it; to that end, some scholars argue it would not be difficult for an astronomer to use Euclid
Euclid (; grc-gre, Wikt:Εὐκλείδης, Εὐκλείδης; BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the ''Euclid's Elements, Elements'' trea ...
's own work to derive the Tusi couple on their own, and that Copernicus most likely did this instead of stealing. Before Copernicus ever published the work on his geometrical mechanism, he had written at length his dissatisfaction over Ptolemaic astronomy
In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, an ...
and the use of the equant, so some scholars then purport that it was not unfounded for Copernicus to have rederived the Tusi couple without having seen it as he had clear motive to do so. Also, some scholars that argue Copernicus did commit plagiarism say that by never claiming it as his own, he inherently condemns himself. However, others critique that mathematicians do not normally claim work like other scientists, so declaring a theorem for oneself is an exception and not the norm. Therefore, there is motive and some explanation as to why and how Copernicus did not plagiarize, despite the evidence against him.
See also
* List of modern-day Muslim scholars of Islam
* List of Iranian scientists
The following is a non-comprehensive list of Iranian scientists, engineers, and scholars who lived from antiquity up until the beginning of the modern age. For the modern era, see List of contemporary Iranian scientists, scholars, and engineer ...
* List of Shi'a Muslims
The following is a list of notable Shia Muslims.
Scientists, mathematicians and academics
* Ibn Sina or Avicenna- was a Persian polymathwho is regarded as one of the most significant physicians, astronomers, philosophers, and writers of ...
* Persian science
Iran has made considerable advances in science and technology through education and training, despite international sanctions in almost all aspects of research during the past 30 years. Iran's university population swelled from 100,000 in 1979 ...
* Science in the medieval Islamic world
Science in the medieval Islamic world was the science developed and practised during the Islamic Golden Age under the Umayyads of Córdoba, the Abbadids of Seville, the Samanids, the Ziyarids, the Buyids in Persia, the Abbasid Caliphate and ...
* Shen Kuo
Shen Kuo (; 1031–1095) or Shen Gua, courtesy name Cunzhong (存中) and pseudonym Mengqi (now usually given as Mengxi) Weng (夢溪翁),Yao (2003), 544. was a Chinese polymathic scientist and statesman of the Song dynasty (960–1279). Shen wa ...
References
Further reading
*
*
* Encyclopædia Iranica, "AḴLĀQ-E NĀṢERĪ", G.M. Wicken
Encyclopædia Iranica , Articles
* Encyclopædia Iranica, "AWṢĀF AL-AŠRĀF", G.M. Wicken
Welcome to Encyclopaedia Iranica
* Encyclopædia Iranica, "Nasir al-Din al-Tusi" George Salib
Welcome to Encyclopaedia Iranica
External links
*
PDF version
*
Biography by Islamic Insights
Islam Online.
An 18th century Sanskrit translation of Nasir al-Din al-Tusi's recension of Euclid's'' Elements''.
{{DEFAULTSORT:Tusi, Nasir Din
People from Tus, Iran
Scientists who worked on qibla determination
Iranian Shia scholars of Islam
1201 births
1274 deaths
13th-century Iranian astronomers
13th-century Iranian mathematicians
13th-century Iranian philosophers
13th-century Muslim scholars of Islam
Iranian ethicists
Scholars of the Ilkhanate
13th-century inventors
13th-century Shia Muslims