1) His Biography:
In the Islamic Middle Ages, Nasir al-Din al-Tusi was a prolific writer and renowned scholar who produced works in a variety of philosophical and scientific disciplines. He was a multi-talented individual who succeeded in a variety of academic fields, including mathematics, philosophy, astronomy, architecture, theology, Islamic medicine, occult sciences, music, logic, physiology, literature, and geography. He was also proficient in many other fields of study.
Years before anyone had even considered them, he produced important discoveries in the fields of trigonometry and astronomy. In Maragha, modern-day Azerbaijan, he helped establish one of the largest astronomical observatories in the Islamic world. He is renowned for developing the astronomical tables for planetary motions that future astrologers would utilize. He began writing when he was a student and developed into a gifted and knowledgeable intellectual.
When he was abducted and employed as a scientific advisor by Mongol leader Hulagu Khan, his path of discovery and research on several topics began. He is recognized with writing over 150 books in Arabic and Persian on both secular and Islamic topics. He translated some of the most renowned Arabic books by mathematicians and astrologers.
Nasir al-Din al-Tusi, also known as Khwaja Muhammad ibn Muhammad ibn al-Hasan al-Tusi, was born on February 18, 1201, into a wealthy and well-educated Twelver Shi’ah family in Tus, medieval Kharasan (now northeastern Iran). He dedicated his entire life to realizing his father’s aim of being a knowledgeable scholar after losing him when he was a child. His education began at Tus, where his uncle taught him mathematics while other teachers taught him physics, logic, and philosophy. He relocated to Nishapur as a teenager to pursue more challenging studies in mathematics, philosophy, and medicine. He then traveled to Mosul to attend courses in astronomy and mathematics.
He wrote a short booklet of intellectual Sufi works called “Awsaf al-Ashraf” (The Attributes of the Illustrious) while attending Mosul University. He finished his studies in the early 1230s and sought refuge at the Isma’ili fort from the Mongols who had conquered Tus. There, he spent the next 25 years studying philosophy, astronomy, logic, and mathematics. He wrote “Tahrir al- Majisti” (Commentary on the Almagest) in 1247 as an introduction to trigonometry and demonstrated several techniques for computing sine tables. At 1256, while he was in Alamut, the Isma’ili capital, the Mongols under Hulagu Khan invaded and seized him. However, because of his expertise, talent, and skills, he was chosen as Hulagu’s scientific advisor.
After obtaining Hulagu’s approval, he started building the Rasad Khaneh Observatory in Maragha in 1259 and remained in charge of it until his passing. In addition to having the best instruments, it also had a library and a school. One of his most significant astronomical works, the four-volume “Zij-i ilkhani” (Ilkhanic Tables), was finished in 1272 and presents the study conducted at the observatory. In addition to the more than 150 books he wrote during his lifetime, he also translated numerous important works by famous mathematicians and astrologers into Arabic, including those by Archimedes, Autolycus, Ptolemy, Hypsicles, Theodosius, and Menelaus. ‘Akhlaq-i-Nasri’ (The Nasirean Ethics), ‘Al-Tadhkirah fi’ilm al-hay’ah’ (Memoir on Astronomy), ‘Tasawwurat’ (Notions), ‘Asas al-iqtibas’ (Foundations of Inference), and ‘Mi’yar al-ash’ar’ are some of his most notable works.
In 1256, after being approved by Hulagu Khan, he wed a Mongol. He traveled to Baghdad in 1274 with several of his pupils, where he passed away on June 26 at the age of 73. Nasireddin is the name of a lunar crater on the southern hemisphere of the moon that is 60 km in diameter. In honor of this ancient Persian scientist are the Shamakhy Observatory in Republic of Azerbaijan and the K.M. Toosi University of Technology in Iran. In 1979, Soviet astronomer Nikolai Stepanovich Chernykh made the discovery of a minor planet, which he gave the designation “10269 Tusi.” The Republic of Azerbaijan released an honorary stamp in 2009 that was dedicated to al-Tusi. In February 2013, Google produced a doodle in honor of his 812th birthday.
2) Main Works:
Nasirean Ethics:
There are three parts of Akhlaq-i Nasiri. The first section is the Persian translation of the older philosopher Miskawayh’s Refinement of Morals (Tahdhib al-Akhlaq). As the most fundamental social unit, the family is discussed in the second section along with home administration and mutual rights. The third section discusses Nasir al-Din al-Tusi’s political views. The influence of Platonic, Neoplatonic, and Aristotelian political concepts can be observed in this section. He also mentions the views of the Pre-Islamic Achaemenid and Sasanian kings of Iran.
Memoir on Astronomy:
Tadhkira was written by Tusi, to be “a summary account of `astronomy’ presented in narrative form. The details are expounded, and proofs of the validity are furnished in the Almagest. Indeed, ours would not be a complete science if taken in isolation from the Almagest for it is a report of what is established therein.” As a result, it serves as both a commentary on the Almagest and a description of medieval Arabic cosmology. Ilkhanic Tables:
The book includes tables for figuring out the names of the stars and the positions of the planets. It contained information obtained from observations taken over a 12-year period in the Maragha observatory, which was finished in 1272. The Zij-i Ilkhani’s planetary placements, which were derived from the Zijs of ibn Al-‘Alam and Ibn Yunis (cf. 10 AD), were so flawed that they received harsh criticism from later astronomers like Shams al-Din Muhammad al-Wabkanawi (1254-1320 AD) and Rukn al-Din al-Amuli.
Commentary on Avicenna’s Isharat:
A philosophical commentary on Avicenna’s book Al-isharat wa al-tanbihat is titled Sharh al-Isharat (Commentary on Isharat) (Remarks and Admonitions). In reaction to Fakhr Razi’s criticism of Avicenna in a book with the same title, Nasir al-Din al-Tusi wrote this commentary to defend his philosophy.
Summation of Belief:
In his book Tajrid al-Kalam, Nasir al-Din al-Tusi discusses Shia doctrine. The Tajrid, written by Nasir addin Tusi, is the most well-known academic work in Shiite theology and the most potent apologetic ever produced.
3) Main Themes in his Writings:
Astronomy:
Hulegu Khan was persuaded to build an observatory by Tusi in order to create precise astronomical tables for improved astrological forecasts. The Rasad Khaneh observatory was built in Azarbaijan, south of the Aras River, and to the west of Maragheh, the Ilkhanate Empire’s capital, starting in 1259.
Based on observations conducted in this observatory, which was at the time the most sophisticated, Tusi created extremely accurate tables of planetary motions that are presented in his book Zij-i Ilkhani (Ilkhanic Tables). Astronomical tables in this book can be used to determine the names of the stars and the positions of the planets. His planetary system model, which is said to have been the most sophisticated of its era, was widely applied up until Nicolaus Copernicus’s invention of the heliocentric model.
He is regarded by many as one of the most accomplished astronomers of his day, ranking between Ptolemy and Copernicus. Gregory Chioniades, a Byzantine scholar, studied under Shams al-Din al-Bukhari, who in turn had schooled astronomer Manuel Bryennios in Constantinople around the year 1300.
He developed a geometrical method known as a Tusi-couple, which produces linear motion from the sum of two circular motions, for his planetary models. He substituted Ptolemy’s troublesome equant for several planets using this method, but he was unable to do so for Mercury; this difficulty was eventually resolved by Ibn al-Shatir and Ali Qushji. Later, the Tusi couple appeared in both Nicolaus Copernicus’ heliocentric Copernican model and Ibn al-Shatir’s geocentric model. Additionally, he contributed to the development and use of several astronomical instruments, including the astrolabe, by calculating the value for the annual precession of the equinoxes.
Ptolemy’s use of observable evidence to demonstrate that the Earth was at rest was questioned by Tusi, who noted that such arguments were inconclusive. Although this does not imply that he believed in the earth’s mobility, he and his 16th-century commentator al-Birjandi held that the only way to prove the earth’s immobility was through physical principles inherent in natural philosophy. Tusi’s critiques of Ptolemy were comparable to the justifications Copernicus offered for the rotation of the Earth in 1543.
In his Tadhkira, Tusi talks on the Milky Way’s true essence: “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, in 1610, Galileo Galilei used a telescope to explore the Milky Way and found that it is made of a great number of dim stars. This was the first direct evidence that the Milky Way is made of many stars.
Mathematics:
Al-Tusi was the first to publish a trigonometry work that was not related to astronomy. In his Treatise on the Quadrilateral, Al-Tusi provided a thorough explanation of spherical trigonometry, which is separate from astronomy. Trigonometry first became recognized as a separate field of pure mathematics from astronomy, with which it had long been associated, in the writings of Al-Tusi.
In spherical trigonometry, he was the first to enumerate the six different situations of a right triangle. This came after earlier work by Muslim mathematicians Abu al-Wafa al-Buzajni and Al-Jayyani as well as Greek mathematicians like Menelaus of Alexandria, who authored the book Sphaerica on spherical trigonometry. The well-known Sine Law for plane triangles can be found in his work On the Sector Figure. Additionally, he discovered the law of tangents for spherical triangles, established the sine law for spherical triangles, and presented proofs for each of these laws.
Colour Theory:
Ibn-Sina described three paths from black to white, one via grey, one via red, and one via green. Aristotle had proposed that all hues can be aligned on a single line from black to white. There are at least five of these paths, according to Al-Tusi: lemon (yellow), blood (red), pistachio (green), indigo (blue), and grey. The Revision of Optics (Tanqih al-Manazir) textbook by Kamal al-Din al-Farisi, which was widely reproduced in the Middle East until at least the nineteenth century, essentially reduced color space to two dimensions. A model of colour space that is essentially three-dimensional was put forth by Robert Grosseteste.
Biology:
Tusi covered several biological subjects in his Akhlaq-i Nasiri. He defended a version of Aristotle’s scala naturae that prioritized man over all other living things, including plants, animals, minerals, and the elements. The closest thing to minerals, according to him, are “grasses which grow without sowing or cultivation, by the mere mingling of elements.” 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” he regarded the date palm as the most advanced plant.
The lowest creatures are those that reproduce like grass but are incapable of mating, such as earthworms and some insects. These animals are found “near the region of plants.” The antlers, horns, teeth, and claws that distinguish the creatures that “achieve the stage of perfection” are fully evolved weapons.
The fact that Tusi claimed that “the Animal Soul [comprising the faculties of perception and movement …] is restricted to individuals of the animal species” and that “Human Soul, […] mankind is distinguished and particularized among other animals” by having a “Human Soul” suggests that he believed that man belonged to the animal kingdom. Some academics have claimed that Tusi subscribed to some form of evolutionary theory based on his writings on biology. Tusi implied that species change with time, but he didn’t say it out loud.
Philosophy:
Tusi wrote extensively about philosophy. His differences with Avicenna, a fellow philosopher, are included in his intellectual writings. The English title of his most well-known philosophical work is Akhlaq-i Nasiri, or Nasirean Ethics. He explores and contrasts Islamic ethics with Aristotelian and Platonian ethics in this essay. In the Muslim world, particularly in India and Persia, Tusi’s book became a well-known ethical work. The theology of Shi’ite Islam was impacted by Tusi’s work as well. In Shi’ite theology, his book Targid, also known as Catharsis, is significant. He also made five contributions to the field of logic, five works that were well-liked by his contemporaries and gained reputation throughout the Muslim world.
4) His Legacy in Muslim Philosophy:
A significant legacy was also left by Nasir al-Din al-Tusi. He is recognized as one of the finest scientists of medieval Islam since he is frequently credited for developing trigonometry into a separate branch of mathematics.
In 657/1259, Tusi persuaded Hulagu to establish the renowned observatory (rasad khanah) at Maraghah, Adharbaijan, which was outfitted with the best instruments, “some of them created for the first time.” This achievement is Tusi’s main claim to fame. He created the Zij al-Ilkhani astrological tables in this location, and they “became popular across Asia, even in China.” This observatory was significant in three additional areas in addition to its dedication to the advancement of astronomy and mathematics in the late seventh/early thirteenth century. It was the first observatory whose ongoing and one-time costs were covered by endowments, paving the way for the funding of further observatories in the future.
Second, Tusi made the Maraghah observatory a “splendid assembly” of the men of knowledge and learning by making “special arrangements” for the teaching of philo-sophical sciences in addition to mathematics and astronomy and by allocating the income from endowments to stipends, just as Ibn Tufail transformed the Court of Caliph ‘Abd al-Mu’min into an enviable intellectual.
Thirdly, there was a sizable library attached to the observatory where the infallible treasures of knowledge taken by the Mongols and Tartars during their invasions of Syria, Iraq, Baghdad, and other lands were kept. The library had more than 400,000 books in it, according to Ibn Shakir. Hulagu’s support of Tusi is particularly significant in the history of Muslim thought during a time of massive political destruction and intellectual decline. In the late seventh/early thirteenth centuries, Tusi’s personality served as the focal point for the resurgence and advancement of philosophical sciences. He was referred to be “the instructor of man” by the Persians (ustad albashar).
He was considered by Bar-Hebraeus to be “a man of immense wisdom in all disciplines of philosophy.” He looks to be an “encyclopedist” to Ivanow, and Afnan regards him as “the most capable… interpreter of Avicenna in Persia.”
One cannot help but be struck by the “remarkable industry” exhibited by him in “editing and enhancing” the translations of Greek mathematicians and astronomers done by Thabit bin Qurrah, Qusta bin Luqa, and Ishaq bin Hunain. Ivanow credits him with “something like one hundred and fifty pieces,” but Brockelmann lists only fifty-nine of his currently published works. The list provided by Mudarris Ridwi totals 131 titles, excluding 21 titles for which Tusi’s authorship is questionable.
Tusi’s perspective is primarily that of a revivalist, and his works are typically eclectic in nature even though he is an outstanding scholar rather than a creative mind. Although he is eclectic and a revivalist, he nevertheless exhibits originality, at least in the way he presents his content. His adaptability truly astounds. His many and varied interests include dogmatism, history, literature, music, astronomy, mathematics, physics, medicine, and minerals