abu rayhan al-biruni……..Barry Wymore





Abū Naṣr Manṣur
Abū Naṣr Manṣur



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For the lunar crater, see Al-Biruni (crater). For the university, see Al-Beroni University.


An imaginary rendition of Al Biruni on a 1973 Sovietpost stamp

Full nameAbū Rayḥān Muḥammad ibn Aḥmad Al-BirunīBorn4/5 September 973
Kath, Khwarezm, Samanid Empire(modern-day Uzbekistan)Died13 December 1048 (aged 75)
Ghazni, Ghaznavid Empire (modern-dayAfghanistan)EraIslamic Golden AgeRegionKhwarezm, Central Asia
Ziyarid dynasty (Rey)[1]
Ghaznavid dynasty (Ghazni)[2]

Main interests

Geology, physics, anthropology,comparative sociology, astronomy,astrology, chemistry, history, geography,mathematics, medicine, psychology,philosophy, theology

Notable ideas

Founder of Indology, geodesy

Major works

The Remaining Signs of Past Centuries,Gems, Indica, The Mas’udi Canon,Understanding Astrology

Influenced by

Muhammad, Aristotle, Ptolemy, Aryabhata,Brahmagupta, Abū Ḥanīfa Dīnawarī, Rhazes, al-Sijzi, Iranshahri, Abu Nasr Mansur, Avicenna, al-Battani


Al-Sijzi, Avicenna, Omar Khayyam, al-Khazini,Zakariya al-Qazwini, Maragha observatory,Islamic science, Islamic philosophy

Abū al-Rayhān Muhammad ibn Ahmad al-Bīrūnī (Chorasmian/Persian: ابوریحان بیرونی‎‎ Abū Rayḥān Bērōnī;[3][4] New Persian: Abū Rayḥān Bīrūnī[5]) (4/5 September 973 – 13 December 1048), known as Al-Biruni (Arabic: البيروني‎) in English,[6] was a Khwarezmian Iranian[7][8][9]Muslim[10] scholar and polymath.

Al-Biruni is regarded as one of the greatest scholars of the medieval Islamic era and was well versed in physics, mathematics,astronomy, and natural sciences, and also distinguished himself as a historian,chronologist and linguist.[9] He was conversant in Khwarezmian, Persian, Arabic,Sanskrit, and also knew Greek, Hebrew andSyriac. He spent a large part of his life inGhazni in modern-day Afghanistan, capital of the Ghaznavid dynasty which was based in what is now central-eastern Afghanistan. In 1017 he traveled to the Indian subcontinent and authored “Tarikh Al-Hind” (History of India) after exploring the Hindu faith practised in India. He is given the titles the “founder of Indology”. He was an impartial writer on custom and creeds of various nations, and was given the title al-Ustadh(“The Master”) for his remarkable description of early 11th-century India.[9] He also made contributions to Earth sciences, and is regarded as the “father of geodesy” for his important contributions to that field, along with his significant contributions togeography.


He was born in the outer district of Kath, the capital of the Afrighid dynasty ofKhwarezm[11] (or Chorasmia).[12] The wordBiruni means “from the outer-district” inPersian, and so this became his nisba: “al-Bīrūnī” = “the Birunian”.[12] His first twenty-five years were spent in Khwarezm where he studied Islamic jurisprudence, theology, grammar, mathematics, astronomy, medicsand other sciences.[12] The IranianKhwarezmian language, which was the language of Biruni,[13][14] survived for several centuries after Islam until the Turkification of the region, and so must some at least of the culture and lore of ancient Khwarezm, for it is hard to see the commanding figure of Biruni, a repository of so much knowledge, appearing in a cultural vacuum.[15]

Al-Biruni’s bust at an entrance to National library of Tajikistan

He was sympathetic to the Afrighids, who were overthrown by the rival dynasty ofMa’munids in 995. Leaving his homeland, he left for Bukhara, then under the Samanid ruler Mansur II the son of Nuh. There he also corresponded with Avicenna[16] and there are extant exchanges of views between these two scholars.

In 998, he went to the court of the Ziyarid amir of Tabaristan, Shams al-Mo’ali Abol-hasan Ghaboos ibn Wushmgir. There he wrote his first important work, al-Athar al-Baqqiya ‘an al-Qorun al-Khaliyya (literally: “The remaining traces of past centuries” and translated as “Chronology of ancient nations” or “Vestiges of the Past”) on historical and scientific chronology, probably around 1000 A.D., though he later made some amendments to the book. He also visited the court of theBavandid ruler Al-Marzuban. Accepting the definite demise of the Afrighids at the hands of the Ma’munids, he made peace with the latter who then ruled Khwarezm. Their court at Gorganj (also in Khwarezm) was gaining fame for its gathering of brilliant scientists.

In 1017, Mahmud of Ghazni took Rey. Most scholars, including al-Biruni, were taken to Ghazni, the capital of the Ghaznavid dynasty.[1] Biruni was made court astrologer[17] and accompanied Mahmud on his invasions into India, living there for a few years. Biruni became acquainted with all things related to India. He may even have learned some Sanskrit.[18] During this time he wrote the Kitab ta’rikh al-Hind, finishing it around 1030.[19]

Mathematics and astronomyEdit

An illustration from al-Biruni’s astronomical works, explains the different phases of the moon.

Diagram illustrating a method proposed and used by Al-Biruni to estimate the radius and circumference of the Earth

Ninety-five of 146 books known to have been written by Bīrūnī, were devoted to astronomy, mathematics, and related subjects like mathematical geography.[20] Biruni’s major work on astrology[21] is primarily an astronomical and mathematical text, only the last chapter concerns astrological prognostication. His endorsement of astrology is limited, in so far as he condemnshorary astrology[22] as ‘sorcery’.

In discussing speculation by other Muslim writers on the possible motion of the Earth, Biruni acknowledged that he could neither prove nor disprove it, but commented favourably on the idea that the Earth rotates.[23] He wrote an extensive commentary on Indian astronomy in the Kitab ta’rikh al-Hind, in which he claims to have resolved the matter of Earth’s rotation in a work on astronomy that is no longer extant, his Miftah-ilm-alhai’a (Key to Astronomy):

[T]he rotation of the earth does in no way impair the value of astronomy, as all appearances of an astronomic character can quite as well be explained according to this theory as to the other. There are, however, other reasons which make it impossible. This question is most difficult to solve. The most prominent of both modern and ancient astronomers have deeply studied the question of the moving of the earth, and tried to refute it. We, too, have composed a book on the subject called Miftah-ilm-alhai’a (Key to Astronomy), in which we think we have surpassed our predecessors, if not in the words, at all events in the matter.[24]

In his description of Sijzi’s astrolabe he hints at contemporary debates over the movement of the earth. He carried on a lengthy correspondence and sometimes heated debate with Ibn Sina, in which Biruni repeatedly attacks Aristotle’s celestial physics: he argues by simple experiment that vacuum must exist;[25] he is “amazed” by the weakness of Aristotle’s argument against elliptical orbits on the basis that they would create vacuum;[26] he attacks the immutability of the celestial spheres;[27] and so on.

In his major extant astronomical work, theMas’ud Canon, Biruni utilizes his observational data to disprove Ptolemy’s immobile solarapogee.[28] More recently, Biruni’s eclipse data was used by Dunthorne in 1749 to help determine the acceleration of the moon[29]and his observational data has entered the larger astronomical historical record and is still used today[30] in geophysics and astronomy.


Al-Biruni contributed to the introduction of theexperimental scientific method to mechanics, unified statics and dynamics into the science of mechanics, and combined the fields ofhydrostatics with dynamics to createhydrodynamics.[citation needed]


Four directions and Political divisions of Iran by Abū Rayḥān al-Bīrūnī

Bīrūnī also devised his own method of determining the radius of the earth by means of the observation of the height of a mountain and carried it out at Nandana in Pind Dadan Khan (present-day Pakistan).[31]

See also: History_of_geodesy § Biruni

Pharmacology and mineralogyEdit

Due to an apparatus he constructed himself, he succeeded in determining the specific gravity of a certain number of metals and minerals with remarkable precision.[32]

History and chronologyEdit

Biruni’s main essay on political history, Kitāb al-musāmara fī aḵbār Ḵᵛārazm (Book of nightly conversation concerning the affairs of Ḵᵛārazm) is now known only from quotations in Bayhaqī’s Tārīkh-e masʿūdī. In addition to this various discussions of historical events and methodology are found in connection with the lists of kings in his al-Āthār al-bāqiya and in the Qānūn as well as elsewhere in the Āthār, in India, and scattered throughout his other works.[33]

History of ReligionsEdit

Bīrūnī is one of the most important Muslim authorities on the history of religion.[34] Al-Biruni was a pioneer in the study of comparative religion. He studied Zoroastrianism, Judaism, Hinduism, Christianity, Buddhism, Islam, and other religions. He treated religions objectively, striving to understand them on their own terms rather than trying to prove them wrong. His underlying concept was that all cultures are at least distant relatives of all other cultures because they are all human constructs. “What al-Biruni seems to be arguing is that there is a common human element in every culture that makes all cultures distant relatives, however foreign they might seem to one another.” (Rosenthal, 1976, p. 10). Al-Biruni was disgusted by scholars who failed to engage primary sources in their treatment of Hindu religion. He found existing sources on Hinduism to be both insufficient and dishonest. Guided by a sense of ethics and a desire to learn, he sought to explain the religious behavior of different groups.

Al-Biruni divides Hindus into an educated and an uneducated class. He describes the educated as monotheistic, believing that God is one, eternal, and omnipotent and eschewing all forms of idol worship. He recognizes that uneducated Hindus worshipped a multiplicity of idols yet points out that even some Muslims (such as theJabiriyya) have adopted anthropomorphic concepts of God. (Ataman, 2005)


Bīrūnī’s fame as an Indologist rests primarily on two texts.[35] Al-Biruni wrote an encyclopedic work on India called “Tarikh Al-Hind” (History of India) in which he explored nearly every aspect of Indian life, including religion, history, geography, geology, science, and mathematics. He explores religion within a rich cultural context. He expresses his objective with simple eloquence: I shall not produce the arguments of our antagonists in order to refute such of them, as I believe to be in the wrong. My book is nothing but a simple historic record of facts. I shall place before the reader the theories of the Hindus exactly as they are, and I shall mention in connection with them similar theories of the Greeks in order to show the relationship existing between them.(1910, Vol. 1, p. 7;1958, p. 5)

An example of Al-Biruni’s analysis is his summary of why many Hindus hate Muslims. He explains that Hinduism and Islam are totally different from each other. Moreover, Hindus in 11th century India had suffered through waves of destructive attacks on many of its cities, and Islamic armies had taken numerous Hindu slaves to Persia which, claimed Al-Biruni, contributed to Hindus becoming suspicious of all foreigners, not just Muslims. Hindus considered Muslims violent and impure, and did not want to share anything with him. Over time, Al-Biruni won the welcome of Hindu scholars. Al-Biruni collected books and studied with these Hindu scholars to become fluent in Sanskrit, discover and translate into Arabic the mathematics, science, medicine, astronomy and other fields of arts as practiced in 11th century India. He was inspired by the arguments offered by Indian scholars who believed earth must be ellipsoid shape, with yet to be discovered continent at earth’s south pole, and earth’s rotation around the sun is the only way to fully explain the difference in daylight hours by latitude, seasons and earth’s relative positions with moon and stars.[36] Al-Biruni was also critical of Indian scribes who he believed carelessly corrupted Indian documents while making copies of older documents.[37] Al-Biruni’s translations as well as his own original contributions reached Europe in 12th and 13th century, where they were actively sought.

While others were killing each other over religious differences, Al-Biruni had a remarkable ability to engage Hindus in peaceful dialogue. Mohammad Yasin puts this dramatically when he says, “The Indica is like a magic island of quiet, impartial research in the midst of a world of clashing swords, burning towns, and burned temples.” (Indica is another name for Al-Biruni’s history of India). (Yasin, 1975, p. 212).


Most of the works of Al-Biruni are in Arabicalthough he wrote one of his masterpieces, the Kitab al-Tafhim apparently in both Persian and Arabic, showing his mastery over both languages.[38] Bīrūnī’s catalogue of his own literary production up to his 65th lunar/63rd solar year (the end of 427/1036) lists 103 titles divided into 12 categories: astronomy, mathematical geography, mathematics, astrological aspects and transits, astronomical instruments, chronology, comets, an untitled category, astrology, anecdotes, religion, and books of which he no longer possesses copies.[39] His extant works include:

Critical study of what India says, whether accepted by reason or refused (Arabic تحقيق ما للهند من مقولة معقولة في العقل أم مرذولة), also known as the Indica – a compendium of India’s religion and philosophyThe Book of Instruction in the Elements of the Art of Astrology (Kitab al-tafhim li-awa’il sina‘at al-tanjimThe Remaining Signs of Past Centuries(Arabic الآثار الباقية عن القرون الخالية) – a comparative study of calendars of different cultures and civilizations, interlaced with mathematical, astronomical, and historical information.The Mas’udi Canon (Persian قانون مسعودي) – an extensive encyclopedia on astronomy, geography, and engineering, named after Mas’ud, son of Mahmud of Ghazni, to whom he dedicated.Understanding Astrology (Arabic التفهيم لصناعة التنجيم) – a question and answer style book about mathematics and astronomy, in Arabic and Persian.Pharmacy – about drugs and medicines.Gems (Arabic الجماهر في معرفة الجواهر) about geology, minerals, and gems, dedicated to Mawdud son of Mas’ud.AstrolabeA historical summary book.History of Mahmud of Ghazni and his fatherHistory of KhawarezmChronicle of NationsEditPersian workEdit

Although he preferred Arabic to Persian in scientific writing, his Persian version of the Al-Tafhim[38] is one of the most important of the early works of science in the Persian language, and is a rich source for Persian prose and lexicography.[38] The book covers the Quadrivium in a detailed and skilled fashion.[38]


Oblique view of Al-Biruni (crater), on the far side of the moon. North is at top.

The crater Al-Biruni on the Moon is named after him.

In June 2009 Iran donated a scholar pavilion to United Nations Office in Vienna which is placed in the central Memorial Plaza of theVienna International Center.[40] The Persian Scholars Pavilion at United Nations in Vienna,Austria is featuring the statues of four prominent Iranian figures. Highlighting the Iranian architectural features, the pavilion is adorned with Persian art forms and includes the statues of renowned Iranian scientistsAvicenna, Abu Rayhan Biruni, Zakariya Razi(Rhazes) and Omar Khayyam.[41][42]

The statue of Al-Biruni in Persian Scholars Pavilion, United Nations Office in Vienna, Austria

The statue of Al-Biruni in United Nations Office in Vienna as a part ofPersian Scholars Pavilion donated byIran

Notes and references

Further reading

3rd Shia Imam Husain…..Barry Wymore




Prophet Mohammed
Henry IV of France

Prophet Mohammed
Henry IV of France


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This article is about Husayn ibn Ali (626–680). For the modern political figure (1854–1931), seeHussein bin Ali, Sharif of Mecca.

Husayn ibn Ali
حسين بن علي  (Arabic)
2nd Imam of Nizari-Ismaili and Taiyabi-Mustaali
3rd Imam of Sevener, Twelver, and Zaydi Shia

The shrine of Husayn, as seen from the shrine ofAbbas in Karbala, Karbala Governorate, Iraq

Bornc. 8 January 626CE
(3Sha’aban 04 AH)[1]
Medina, HejazDiedc. 10 October 680 (aged 54)
(10 Muharram 61 AH)
Karbala, Umayyad Empire (now inIraq)Cause of deathBeheaded at the Battle of KarbalaResting placeShrine of Imam Hussein, Karbala, Iraq
32°36′59″N 44°1′56.29″EResidenceMedina, HejazEthnicityHejazi Arab, Quraysh tribeKnown forBattle of KarbalaTitle


(Arabic for Father of Freedom)
(Arabic for The Martyr)as-Sibt[2]
(Arabic for The Grandson)Sayyidu Shabābi Ahlil Jannah[2][3]
(Arabic for Leader of the Youth of Paradise)ar-Rashīd[2]
(Arabic for The Rightly Guided)at-Tābi li Mardhātillāh[2]
(Arabic for The Follower of Gods Will)al-Mubārak[2]
(Arabic for The Blessed)at-Tayyib[2]
(Arabic for The Pure)Sayyidush Shuhadā[4][5]
(Arabic for Master of the Martyrs)al-Wafī[2]
(Arabic for The Loyal)Üçüncü Ali
(Turkish for Third Ali)

Term670–680 ADPredecessorHasan ibn AliSuccessorAli ibn Husayn Zayn al-AbidinReligionIslamSpouse(s)Shahr Banu
Umme Rubāb
Umme Laylā
Umm Ishāq.Children


‘Alī ibn al-Ḥussein ibn ‘Alī (Zayn al-‘ĀbidīnAli al-Akbar ibn Husayn (Umar ibn HusaynAli al-Asghar ibn HusaynAbu Bakr ibn HusaynSakinah bint HusaynSukayna bint HusaynFatima al-SughraFatimah bint HusaynUmm Kulthum bint HusaynZaynab bint Husayn


Calligraphic representation of Husayn ibn Ali in Hagia Sophia, Istanbul, Turkey.

Entry gate of the shrine of Husayn in Karbala,Iraq

Husayn ibn ‘Alī ibn Abī Tālib (Arabic: الحسين بن علي بن أبي طالب‎‎; 8 January 626 – 10 October 680) (3rd/4th Sha’aban 4 AH – 10thMuharram 61 AH), also spelled as Husain,Hussain or Hussein, was the son of Ali ibn Abi Ṭalib (fourth Rashidun Caliph of Sunni Islam, and first Imam of Shia Islam) and Fatimah Zahra (daughter of Muhammad) and the younger brother of Hasan ibn Ali. Husayn is an important figure in Islam, as he is a member of the Ahl al-Bayt (the household of Muhammad) and Ahl al-Kisa, as well as being the third Shia Imam.

Hussain became the head of Shia Imam and the head of Banu Hashim after the death of his older brother, Hasan ibn Ali, in 670 (50 AH). His father’s supporters (Shi’a Ali) in Kufagave their allegiance to him. However, he told them he was still bound to the peace treaty between Hasan and Muawiyah I and they should wait until Muawiyah was dead. Later, Hussain did not accept the request of Muawiyah for the succession of his son,Yazid I, and considered this action a breach of the Hasan–Muawiya treaty.[6] When Muawiyah I died in 680, Husayn refused to pledge allegiance to Yazid I, who had just been appointed as Umayyad caliph by Muawiyah, because he considered theUmayyads an oppressive and religiously misguided regime. He insisted on his legitimacy based on his own special position as a direct descendant of Muhammad and his legitimate legatees. As a consequence, he left Medina, his home town, to take refuge inMecca in 60 AH.[6][7] There, the people of Kufa sent letters to him, asking his help and pledging their allegiance to him. So he traveled towards Kufa.[6] At a place near Kufa, known as Karbala, his caravan was intercepted by Yazid I’s army. He was killed and beheaded in the Battle of Karbala on 10 October 680 (10 Moḥarram 61) by Shimr Ibn Thil-Jawshan, along with most of his family and companions.[8]

Anger at Husayn’s death was turned into a rallying cry that helped undermine theUmayyad Caliphate legitimacy and ultimately overthrow the Umayyad Caliphate by Abbasid Revolution.[9][10]

Husayn is highly regarded by Shia Muslimsbecause he refused to pledge allegiance toYazid I,[11] the Umayyad caliph, because he considered the rule of the Umayyadsunjust.[11] The annual memorial for him, his family, his children and his companions is called Ashura (tenth day of Muharram) and is a day of mourning for Shiite Muslims. His action at Karbala fueled the later Shiite movements.[10]

Early lifeEdit

The painting by commemorating the martyrdom of Imam Husayn at the Battle of Karbala, its focus is his half brother Abbas ibn Ali on a white horse [12]

A Quran written by Imam Hussain ibn Ali, from over 1300 years ago

According to most reports, Husayn was born on 8 January 626 CE (3 / 5 Sha’aban 4 AH).[6]Husayn and his brother Hasan were the last descendants of Muhammad living during his lifetime and remaining after his death. There are many accounts of his love for them which refer to them together.[6]

Muhammad is reported to have said that “He who loves me and loves these two, their father and their mother, will be with me at my place on the Day of Resurrection.”[13] and that “Hussain is of me and I am his. Allah loves those who love Hussain. Hussain is a grandson among grandsons.”[13] A narration declares them the “Masters of the Youth of Paradise”; this has been particularly important for the Shia who have used it in support of the right of Muhammad’s descendants to succeed him. Other traditions record Muhammad with his grandsons on his knees, on his shoulders, and even on his back during prayer at the moment of prostrating himself, when they were young.[14]

According to Wilferd Madelung, Muhammad loved them and declared them as his Ahl al-Bayt very frequently.[15] According to popular Sunni belief, it refers to the household of Muhammad. Shia popular view is the members of Muhammad’s family that were present at the incident of Mubahala. According to Muhammad Baqir Majlisi who compiled Bihar al-Anwar, a collection ofahadith, Chapter 46 Verse 15 (Al-Ahqaf) and Chapter 89 Verses 27-30 (Al-Fajr) of theQuran are regarding Husayn ibn-Ali.

The incident of MubahalaEdit

Main article: Event of Mubahala

In the year 10 AH (631/32 CE) a Christian envoy from Najran (now in northern Yemen) came to Muhammad to argue which of the two parties erred in its doctrine concerningIsa (Jesus). After likening Jesus’ miraculous birth to Adam’s (Adem) creation,[a]—who was born to neither a mother nor a father — and when the Christians did not accept the Islamic doctrine about Jesus, Muhammadwas instructed to call them to Mubahalawhere each party should ask God to destroy the false party and their families.[16][17] If anyone dispute with you in this matter [concerning Jesus] after the knowledge which has come to you, say: Come let us call our sons and your sons, our women and your women, ourselves and yourselves, then let us swear an oath and place the curse of God on those who lie.[b][16][18] Sunnite historians, except Tabariwho do not name the participants, mentionMuhammad, Fatimah, Hasan and Husayn, and some agree with the Shia tradition thatAli was also among the participants in this event on the side of Muhammad. Accordingly, in the verse of Mubahala the words “Our sons” is representative of Hasan and Husayn; “our women” would refer to Fatimah; and “ourselves” would be “Ali”.[16][18]

Husayn and caliphateEdit

Muawiyah, the governor of Levant, who had refused Ali’s demands for allegiance, has long been in fight with him.[19] However, when Ali was assassinated and people gave allegiance to Hasan, Muawiyah prepared to fight with him. The battle led to inconclusive skirmishes between the armies of Hasan and Muawiyah. To avoid the agonies of another civil war,Hasan signed the Hasan–Muawiya treatywith Muawiyah, according to which Muawiyah wouldn’t name a successor during his reign and let the Islamic world choose their successor after the latter.[20]

Muawiyah’s eraEdit

See also: Muawiyah I and Umayyad

According to the Shia, Husayn was the third Imam for a period of ten years after the death of his brother Hasan in 669. All of this time but the last six months coinciding with the caliphate of Muawiyah.[21] After the peace treaty with Hasan, Muawiyah set out with his troops to Kufa, where at a public surrender ceremony Hasan rose and reminded the people that he and Husayn were the only grandsons of Muhammad. And that he had surrendered the reign to Muawiyah in the best interest of the community: “0 people, surely it was God who led you by the first of us and Who has spared you bloodshed by the last of us. I have made peace with Mu’awiyah, and I know not whether haply this be not for your trial, and that ye may enjoy yourselves for a time.[c][22] declared Hasan.[20]

In the nine-year period between Hasan’s abdication in 41/660 and his death in 49/669, Hasan and Husayn retired in Medina trying to keep aloof from political involvement for or against Muawiyah.[20][23]

Shiite feelings, however, though not visible above the surface, occasionally emerged in the form of small groups, mostly from Kufa, visiting Hasan and Husayn asking them to be their leaders – a request to which they declined to respond.[16] Even ten years later, after the death of Hasan, when Iraqis turned to his younger brother, Husayn, concerning an uprising, Husayn instructed them to wait as long as Muawiyah was alive due to Hasan’s peace treaty with him.[20] Later on, however, and before his death, Muawiyah named his son Yazid as his successor.[6]

Yazid’s ruleEdit

One of the important points of the treaty made between Hasan and Muawiyah was that Muawiyah not designate anyone as his successor after his death; the choice was left to the Ummah (the Nation). But after the death of Hasan, Muawiyah, thinking that no one would be courageous enough to object his decision as the Caliph, designated his son, Yazid I, as his successor in 680 CE, breaking the treaty.[24] Robert Payne quotes Muawiyah in History of Islam as telling his son Yazid to defeat Husayn, who was surely preparing an army against him, but to deal with him gently thereafter as Husayn was a descendent of Muhammad; but to deal with Abdullah al-Zubair swiftly, as Muawiyah feared him the most.[25]


In April 680, Yazid I succeeded his fatherMuawiyah as the new caliph. Yazid immediately instructed the governor ofMedina to compel Hussayn and few other prominent figures to pledge their allegiance (Bay’ah).[6] Husain, however, refrained from it believing that Yazid was openly going against the teachings of Islam in public and changing the sunnah of Muhammad.[26][27] In his view the integrity and survival of the Islamic community depended on the re-establishment of the correct guidance.[28] He, therefore, accompanied by his household, his sons, brothers, and the sons of Hasan left Medina to seek asylum in Mecca.[6]

While in Mecca Abd Allah ibn al-Zubayr,Abdullah ibn Umar and Abdullah ibn Abbasadvised Husayn bin Ali to make Mecca his base and fight against Yazid from Mecca.[29]On the other hand, the people in Kufa who were informed about Muawiyah ‘s death, sent letters urging Husayn to join them and pledge to support him against Umayyads. Husayn wrote back to them saying that he would send his cousin Muslim ibn Aqeel to report to him on the situation. If he found them united as their letters indicated he would speedily join them, because Imam should act in accordance with the Quran, uphold justice, proclaim the truth, and dedicate himself to the cause of God.[6] The mission of Moslem was initially successful and according to reports 18,000 men pledged their allegiance. But situation changed radically when Yazid appointed Ubayd Allah ibn Ziyad as the new governor of Kufa, ordering him to deal severely with Ibn Aqeel. Before news of the adverse turn of events arrived in Mecca, Husayn set out for Kufa.[6]

On the way, Husayn found that his messenger, Muslim ibn Aqeel, was killed in Kufa. He broke the news to his supporters and informed them that people had deserted him. Then, he encouraged anyone who so wished, to leave freely without guilt. Most of those who had joined him at various stages on the way from Mecca now left him.[6]

Battle of KarbalaEdit

The painting by commemorating the martyrdom of Imam Husayn at the Battle of Karbala, its focus is his half brother Abbas ibn Ali on a white horse [12]

Main article: Battle of Karbala

See also: Maqtal al-Husayn

On his path towards Kufa, Husayn encountered with the army of Ubaydullah ibn Ziyad in his path towards Kufa. Husayn addressed the Kufans army, reminding them that they had invited him to come because they were without an Imam. He told them that he intended to proceed to Kufa with their support, but if they were now opposed to his coming, he would return to where he had come from. However, the army urged him to choose another way. Thus, he turned to left and reached Karbala, where the army forced him not to go further and stop at a location that was without water.[6]

Umar ibn Sa’ad, the head of Kufan army, sent a messenger to Husayn to inquire about the purpose of his coming to Iraq. Husayn answered again that he had responded to the invitation of the people of Kufa but was ready to leave if they now disliked his presence. When Umar ibn Sa’ad, the head of Kufan army, reported it back to Ubaydullah ibn Ziyad, the governor instructed him to offer Ḥusayn and his supporters the opportunity to swear allegiance to Yazid. He also orderedUmar ibn Sa’ad to cut off Husayn and his followers from access to the water of the Euphrates.[6] On the next morning, as ʿOmar b. Saʿd arranged the Kufan army in battle order,Al-Hurr ibn Yazid al Tamimi challenged him and went over to Ḥusayn. He vainly addressed the Kufans, rebuking them for their treachery to the grandson of Muhammad and was killed in the battle.

Nasir al-Din al-Tusi…….Errol flynn





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EditWatch this pageNasir al-Din al-Tusi

Persian Muslim scholar
Nasīr al-Dīn TūsīTitleKhawaja NasirBorn17 February 1201 (11 Jamadi al-Ula 597)Died25 June 1274 (aged 73) (18 Dhu’l-Hijjah 672)EthnicityPersianEraIslamic Golden AgeRegionPersiaReligionIslamJurisprudenceTwelver Shī‘ahCreedAvicennismMain interest(s)Ilm al-Kalam, Islamic Philosophy,Astronomy, Mathematics,Chemistry, Biology and Medicine,Physics, ScienceNotable idea(s)Evolution, Spherical trigonometry,Tusi-coupleNotable work(s)Rawḍa-yi Taslīm, Tajrid al-‘Aqaid,
Akhlaq-i-Nasri, Zij-i ilkhani,
al-Risalah al-Asturlabiyah,
Al-Tadhkirah fi’ilm al-hay’ah

Influenced by

Avicenna, Fakhr al-Din Razi, Mo’ayyeduddin Urdi


Maitham Al Bahrani, ibn Khaldun, Qutb al-Din Shirazi, Ibn al-Shatir, Copernicus

Khawaja Muhammad ibn Muhammad ibn Hasan Tūsī (Persian: محمد بن محمد بن الحسن طوسی‎‎) (born 17 February 1201 in Ṭūs, Khorasan – died on 25 June 1274 in al-Kāżimiyyahdistrict of metropolitan Baghdad), better known as Nasīr al-Dīn Tūsī (Persian: نصیر الدین طوسی‎‎; or simply Tusi in the West), was aPersian[1][2][3][4][5] polymath and prolific writer: An architect, astronomer, biologist, chemist,mathematician, philosopher, physician,physicist, scientist, theologian and Marja Taqleed.[citation needed] He was of the Ismaili-, and subsequently Twelver Shī‘ah Islamicbelief.[6] The Muslim scholar Ibn Khaldun(1332–1406) considered Tusi to be the greatest of the later Persian scholars.[7]


Nasir al-Din Tusi was born in the city of Tus in medieval Khorasan (in north-eastern Iran) in the year 1201 and began his studies at an early age. In Hamadan and Tus he studied theQur’an, Hadith, Shi’a jurisprudence, logic, philosophy, mathematics, medicine and astronomy.[8]

He was apparently 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 travelled far and wide to attend the lectures of renowned scholars and acquire the knowledge, an exercise highly encouraged in his Islamic faith. At a young age he moved to Nishapur to study philosophy under Farid al-Din Damad and mathematics under Muhammad Hasib.[9] He met also Farid al-Din ‘Attar, the legendary Sufimaster who was later killed by Mongol invaders and attended the lectures of Qutb al-Din al-Misri.

In Mosul he studied mathematics and astronomy with Kamal al-Din Yunus (d. 639/1242). Later on he corresponded withSadr al-Din al-Qunawi, the son-in-law of Ibn al-‘Arabi, and it seems that mysticism, as propagated by Sufi masters of his time, was not appealing to his mind and once the occasion was suitable, he composed his own manual of philosophical Sufism in the form of a small booklet entitled Awsaf al-Ashraf “The Attributes of the Illustrious”.

As the armies of Genghis Khan swept his homeland, he was employed by the Ismailisand made his most important contributions in science during this time when he was moving from one stronghold to another.[10] He was captured after the invasion of the Alamutcastle by the Mongol forces.[11]


Tusi has about 150 works, of which 25 are inPersian and the remaining are in Arabic,[12]and there is one treatise in Persian, Arabic and Turkish.[13]

A Treatise on Astrolabe by Tusi, Isfahan 1505

Here are some of his major works:

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 byAbd al-Ali ibn Muhammad ibn al-Husayn al-Birjandi and by Nazzam NishapuriAkhlaq-i-Naseri – A work on ethics.al-Risalah al-Asturlabiyah – A Treatise on astrolabe.Zij-i ilkhani (Ilkhanic Tables) – A major astronomical treatise, completed in 1272.sharh al-isharat (Commentary on Avicenna’s IsharatAwsaf al-Ashraf a short mystical-ethical work in PersianTajrīd al-iʿtiqād (Summation of Belief) – A commentary on Shia doctrines.Talkhis Al Mohassal


Tusi couple from Vat. Arabic ms 319

Tusi couple

During his stay in Nishapur, Tusi established a reputation as an exceptional scholar. “Tusi’s prose writing, which number over 150 works, represent one of the largest collections by a single Islamic author. Writing in both Arabicand Persian, Nasir al-Din Tusi dealt with both religious (“Islamic”) topics and non-religious or secular subjects (“the ancient sciences”).[12] His works include the definitive Arabic versions of the works of Euclid,Archimedes, Ptolemy, Autolycus, andTheodosius of Bithynia.[12]


Further information: Zij-i Ilkhani and Tusi-couple

The Astronomical Observatory of Nasir al-Dīn Tusi.

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 inAzarbaijan, south of the river Aras, and to the west of Maragheh, 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 movementsas 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. Between Ptolemy andCopernicus, he is considered by many[who?] to be one of the most eminent astronomers of his time.

For his planetary models, he invented a geometrical technique called a Tusi-couple, which generates linear motion from the sum of two circular motions. He used this technique to replace Ptolemy’s problematicequant[14] for many planets, but was unable to find a solution to Mercury, which was solved later by Ibn al-Shatir as well as Ali Qushji.[15]The Tusi couple was later employed in Ibn al-Shatir’s geocentric model and Nicolaus Copernicus’ heliocentric Copernican model.[16] He also calculated the value for the annual precession of the equinoxes and contributed to the construction and usage of some astronomical instruments including theastrolabe.

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, but only by physical principles found in natural philosophy.[17]Tusi’s criticisms of Ptolemy were similar to the arguments later used by Copernicus in 1543 to defend the Earth’s rotation.[18]

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 likend to milk in color.” [19] Three centuries later the proof of the Milky Way consisting of many stars came in 1610 whenGalileo Galilei used a telescope to study the Milky Way and discovered that it is really composed of a huge number of faint stars.[20]

Biology and evolutionEdit

In his Akhlaq-i-Nasri, Tusi put forward a basic theory for the evolution of species almost 600 years before Charles Darwin, the English naturalist credited with advancing the idea, was born. He begins his theory of evolution with the universe once consisting of equal and similar elements. According to Tusi, internal contradictions began appearing, and as a result, some substances began developing faster and differently from other substances. He then explains how the elements evolved into minerals, then plants, then animals, and then humans. Tusi then goes on to explain how hereditary variability was an important factor for biological evolution of living things:[21]

“The organisms that can gain the new features faster are more variable. As a result, they gain advantages over other creatures. […] The bodies are changing as a result of the internal and external interactions.”

Tusi discusses how organisms are able toadapt to their environments:[21]

“Look at the world of animals and birds. They have all that is necessary for defense, protection and daily life, including strengths, courage and appropriate tools [organs] […] Some of these organs are real weapons, […] For example, horns-spear, teeth and claws-knife and needle, feet and hoofs-cudgel. The thorns and needles of some animals are similar to arrows. […] Animals that have no other means of defense (as the gazelle and fox) protect themselves with the help of flight and cunning. […] Some of them, for example, bees, ants and some bird species, have united in communities in order to protect themselves and help each other.”

Tusi recognized three types of living things: plants, animals, and humans. He wrote:[21]

“Animals are higher than plants, because they are able to move consciously, go after food, find and eat useful things. […] There are many differences between the animal and plant species, […] First of all, theanimal kingdom is more complicated. Besides, reason is the most beneficial feature of animals. Owing to reason, they can learn new things and adopt new, non-inherent abilities. For example, the trained horse or hunting falcon is at a higher point of development in the animal world. The first steps of human perfection begin from here.”

Tusi then explains how humans evolved from advanced animals:[21]

“Such humans [probablyanthropoid apes] live in the Western Sudan and other distant corners of the world. They are close to animals by their habits, deeds and behavior. […] The human has features that distinguish him from other creatures, but he has other features that unite him with the animal world, vegetable kingdom or even with the inanimate bodies. […] Before [the creation of humans], all differences between organisms were of the natural origin. The next step will be associated with spiritual perfection, will, observation and knowledge. […] All these facts prove that the human being is placed on the middle step of the evolutionary stairway. According to his inherent nature, the human is related to the lower beings, and only with the help of his will can he reach the higher development level.”

Chemistry and physicsEdit

In chemistry and physics, Tusi stated a version of the law of conservation of mass. He wrote that a body of matter is able to change, but is not able to disappear:[21]

“A body of matter cannot disappear completely. It only changes its form, condition, composition, colour and other properties and turns into a different complex or elementary matter.”


Nasir al-Din Tusi was a supporter ofAvicennian logic, and wrote the following commentary on Avicenna’s theory of absolutepropositions:

“What spurred him to this was that in the assertoric syllogisticAristotle and others sometimes used contradictories of absolute propositions on the assumption that they are absolute; and that was why so many decided that absolutes did contradict absolutes. When Avicenna had shown this to be wrong, he wanted to give a way of construing those examples from Aristotle.”[22]


Iranian stamp for the 700th anniversary of his death

A stamp issued in the republic of Azerbaijan in 2009 honoring Tusi

Al-Tusi was the first to write a work on trigonometry independently of astronomy.[23]Al-Tusi, in his Treatise on the Quadrilateral, gave an extensive exposition of spherical trigonometry, distinct from astronomy.[24] 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.[25][26]

He was the first to list the six distinct cases of a right triangle in spherical trigonometry.

This followed earlier work by Greek mathematicians such as Menelaus of Alexandria, who wrote a book on spherical trigonometry called Sphaerica, and the earlier Muslim mathematicians Abū al-Wafā’ al-Būzjānī and Al-Jayyani.

In his On the Sector Figure, appears the famous law of sines for plane triangles.[27]

He also stated the law of sines for spherical triangles,[28][29] discovered the law of tangents for spherical triangles, and provided proofs for these laws.[27]

Influence and legacyEdit

A 60-km diameter lunar crater located on the southern hemisphere of the moon is named after him as “Nasireddin”. A minor planet10269 Tusi discovered by Soviet astronomerNikolai Stepanovich Chernykh in 1979 is named after him.[30][31] The K. N. Toosi University of Technology in Iran and Observatory of Shamakhy in the Republic of Azerbaijan are also named after him. In February 2013, Google celebrated his 812th birthday with a doodle, which was accessible in its websites with Arabic language calling him al-farsi (the Persian).[32][33]

See also


Further reading

External links

Read in another language

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Abu Yusuf Ya’qub ibn Ishaq Al-Kindi……Barry wymore





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EditWatch this pageAl-Kindi

“Alkindus” redirects here. For the insect (bug), see Alkindus (genus).

For the surname, see Al-Kindi (surname).

al-KindīBornc. 801
Basra, MesopotamiaDiedc. 873 (aged approx. 72)
Baghdad, MesopotamiaEraMedieval era (Islamic Golden Age)RegionMiddle East, Arab world, Muslim worldSchoolIslamic theology, philosophy

Main interests

Philosophy, logic, ethics, mathematics,physics, chemistry, psychology,pharmacology, medicine, metaphysics,cosmology, astrology, music theory,Islamic theology (kalam)


Ancient Greek philosophy


Abu Zayd al-Balkhi, Ahmad ibn al-Tayyib al-Sarakhsi, Isaac Israeli ben Solomon, Abu Ma’shar al-Balkhi, Miskawayh,[1] Robert Grosseteste, William Lane Craig

Abu Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (Arabic: أبو يوسف يعقوب بن إسحاق الصبّاح الكندي‎,Latin: Alkindus) (c. 801–873 AD), known as “the Philosopher of the Arabs”, was a MuslimArab philosopher, polymath, mathematician,physician and musician. Al-Kindi was the first of the Muslim peripatetic philosophers, and is unanimously hailed as the “father of Islamic or Arabic philosophy”[2][3][4] for his synthesis, adaptation and promotion of Greek andHellenistic philosophy in the Muslim world.[5]

Al-Kindi was a descendant of the Kinda tribe. He was born in Basra and educated inBaghdad.[6] Al-Kindi became a prominent figure in the House of Wisdom, and a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language. This contact with “the philosophy of the ancients” (as Greek philosophy was often referred to by Muslim scholars) had a profound effect on his intellectual development, and led him to write hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics,logic and psychology, to medicine,pharmacology,[7] mathematics, astronomy,astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors,meteorology and earthquakes.[8][9]

In the field of mathematics, al-Kindi played an important role in introducing Indian numeralsto the Islamic and Christian world.[10] He was a pioneer in cryptanalysis and devised several new methods of breaking ciphers.[11]Using his mathematical and medical expertise, he was able to develop a scale that would allow doctors to quantify the potency of their medication.[12]

The central theme underpinning al-Kindi’s philosophical writings is the compatibility between philosophy and other “orthodox” Islamic sciences, particularly theology. And many of his works deal with subjects that theology had an immediate interest in. These include the nature of God, the soul andprophetic knowledge.[13] But despite the important role he played in making philosophy accessible to Muslim intellectuals, his own philosophical output was largely overshadowed by that of al-Farabiand very few of his texts are available for modern scholars to examine.


Al-Kindi was born in Kufa to an aristocratic family of the Kinda tribe, descended from the chieftain al-Ash’ath ibn Qays, a contemporary of Muhammad. The family belonged to the most prominent families of the tribal nobility of Kufa in the early Islamic period, until it lost much of its power following the revolt of Abd al-Rahman ibn Muhammad ibn al-Ash’ath.[14]His father Ishaq was the governor of Kufa, and al-Kindi received his preliminary education there. He later went to complete his studies in Baghdad, where he was patronized by the Abbasid caliphs al-Ma’mun (ruled 813–833) and al-Mu’tasim (r. 833–842). On account of his learning and aptitude for study, al-Ma’mun appointed him to the House of Wisdom, a recently established centre for the translation of Greek philosophical and scientific texts, in Baghdad. He was also well known for his beautiful calligraphy, and at one point was employed as a calligrapher byal-Mutawakkil.[15]

When al-Ma’mun died, his brother, al-Mu’tasim became Caliph. Al-Kindi’s position would be enhanced under al-Mu’tasim, who appointed him as a tutor to his son. But on the accession of al-Wathiq (r. 842–847), and especially of al-Mutawakkil (r. 847–861), al-Kindi’s star waned. There are various theories concerning this: some attribute al-Kindi’s downfall to scholarly rivalries at the House of Wisdom; others refer to al-Mutawakkil’s often violent persecution of unorthodox Muslims (as well as of non-Muslims); at one point al-Kindi was beaten and his library temporarily confiscated. Henry Corbin, an authority on Islamic studies, says that in 873, al-Kindi died “a lonely man”, in Baghdad during the reign ofal-Mu’tamid (r. 870–892).[15]

After his death, al-Kindi’s philosophical works quickly fell into obscurity and many of them were lost even to later Islamic scholars and historians. Felix Klein-Franke suggests a number of reasons for this: aside from the militant orthodoxy of al-Mutawakkil, theMongols also destroyed countless libraries during their invasion. However, he says the most probable cause of this was that his writings never found popularity amongst subsequent influential philosophers such asal-Farabi and Avicenna, who ultimately overshadowed him.[16]


Al-Kindi was a master of many different areas of thought and was held to be one of the greatest Islamic philosophers of his time.

The Italian Renaissance scholar Geralomo Cardano (1501–1575) considered him one of the twelve greatest minds of the Middle Ages.[17] According to Ibn al-Nadim, al-Kindi wrote at least two hundred and sixty books, contributing heavily to geometry (thirty-two books), medicine and philosophy (twenty-two books each), logic (nine books), and physics(twelve books).[18] His influence in the fields of physics, mathematics, medicine, philosophy and music were far-reaching and lasted for several centuries. Although most of his books have been lost over the centuries, a few have survived in the form of Latintranslations by Gerard of Cremona, and others have been rediscovered in Arabic manuscripts; most importantly, twenty-four of his lost works were located in the mid-twentieth century in a Turkish library.[19]


His greatest contribution to the development of Islamic philosophy was his efforts to make Greek thought both accessible and acceptable to a Muslim audience. Al-Kindi carried out this mission from the House of Wisdom (Bayt al-Hikma), an institute of translation and learning patronized by theAbbasid Caliphs, in Baghdad.[15] As well as translating many important texts, much of what was to become standard Arabic philosophical vocabulary originated with al-Kindi; indeed, if it had not been for him, the work of philosophers like Al-Farabi, Avicenna, and al-Ghazali might not have been possible.[20]

In his writings, one of al-Kindi’s central concerns was to demonstrate the compatibility between philosophy and natural theology on the one hand, and revealed orspeculative theology on the other (though in fact he rejected speculative theology). Despite this, he did make clear that he believed revelation was a superior source of knowledge to reason because it guaranteed matters of faith that reason could not uncover. And while his philosophical approach was not always original, and was even considered clumsy by later thinkers (mainly because he was the first philosopher writing in the Arabic language), he successfully incorporated Aristotelian and (especially) neo-Platonist thought into an Islamic philosophical framework. This was an important factor in the introduction and popularization of Greek philosophy in the Muslim intellectual world.[21]


Al-Kindi took his view of the solar system from Ptolemy, who placed the Earth at the centre of a series of concentric spheres, in which the known heavenly bodies (the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and the stars) are embedded. In one of his treatises on the subject, he says that these bodies are rational entities, whose circular motion is in obedience to and worship of God. Their role, al-Kindi believes, is to act as instruments for divine providence. He furnishes empirical evidence as proof for this assertion; different seasons are marked by particular arrangements of the planets and stars (most notably the sun); the appearance and manner of people varies according to the arrangement of heavenly bodies situated above their homeland.[22]

However, he is ambiguous when it comes to the actual process by which the heavenly bodies affect the material world. One theory he posits in his works is from Aristotle, who conceived that the movement of these bodies causes friction in the sub-lunar region, which stirs up the primary elements of earth, fire, air and water, and these combine to produce everything in the material world. An alternative view found his treatise On Rays is that the planets exercise their influence in straight lines. In each of these, he presents two fundamentally different views of physical interaction; action by contact and action at a distance. This dichotomy is duplicated in his writings on optics.[23]

Some of the notable astrological works by al-Kindi include:[24]

The Book of the Judgement of the Stars, including The Forty Chapters, on questions and elections.On the Stellar RaysSeveral epistles on weather and meteorology, including De mutatione temporumTreatise on the Judgement of Eclipses.Treatise on the Dominion of the Arabs and its Duration (used to predict the end of Arab rule).The Choices of Days (on elections).On the Revolutions of the Years (on mundane astrology and natal revolutions).De Signis Astronomiae Applicitis as Mediciam‘On the Signs of Astronomy as applied to Medicine’Treatise on the Spirituality of the PlanetsOpticsEdit

Two major theories of optics appear in the writings of al-Kindi; Aristotelian and Euclidian. Aristotle had believed that in order for the eye to perceive an object, both the eye and the object must be in contact with a transparent medium (such as air) that is filled with light. When these criteria are met, the “sensible form” of the object is transmitted through the medium to the eye. On the other hand, Euclid proposed that vision occurred in straight lines when “rays” from the eye reached an illuminated object and were reflected back. As with his theories on Astrology, the dichotomy of contact and distance is present in al-Kindi’s writings on this subject as well.

The factor which al-Kindi relied upon to determine which of these theories was most correct was how adequately each one explained the experience of seeing. For example, Aristotle’s theory was unable to account for why the angle at which an individual sees an object affects his perception of it. For example, why a circle viewed from the side will appear as a line. According to Aristotle, the complete sensible form of a circle should be transmitted to the eye and it should appear as a circle. On the other hand, Euclidean optics provided a geometric model that was able to account for this, as well as the length of shadows and reflections in mirrors, because Euclid believed that the visual “rays” could only travel in straight lines (something which is commonly accepted in modern science). For this reason, al-Kindi considered the latter preponderant.[25]

Through the Latin version of the De Aspectibus, Al-Kindi partly influenced the optical investigations of Robert Grosseteste[26] and Roger Bacon.


There are more than thirty treatises attributed to al-Kindi in the field of medicine, in which he was chiefly influenced by the ideas ofGalen.[27] His most important work in this field is probably De Gradibus, in which he demonstrates the application of mathematics to medicine, particularly in the field of pharmacology. For example, he developed a mathematical scale to quantify the strength of drug and a system, based the phases of the moon, that would allow a doctor to determine in advance the most critical days of a patient’s illness.[12]


As an advanced chemist, he was also an opponent of alchemy; he debunked the myth that simple, base metals could be transformed into precious metals such as gold or silver.[28] He is also credited as the first distillers of alcohol, creating the “Alkindus distiller” which was used for the distillation of alcohol.


Al-Kindi authored works on a number of important mathematical subjects, including arithmetic, geometry, the Indian numbers, the harmony of numbers, lines and multiplication with numbers, relative quantities, measuring proportion and time, and numerical procedures and cancellation.[10] He also wrote four volumes, On the Use of the Indian Numerals (Ketab fi Isti’mal al-‘Adad al-Hindi) which contributed greatly to diffusion of the Indian system of numeration in the Middle-East and the West. In geometry, among other works, he wrote on the theory of parallels. Also related to geometry were two works on optics. One of the ways in which he made use of mathematics as a philosopher was to attempt to disprove the eternity of the world by demonstrating that actual infinity is a mathematical and logical absurdity.[29]

The first page of al-Kindi’s manuscript “On Deciphering Cryptographic Messages”, containing the oldest known description of cryptanalysis by frequency analysis.


Al-Kindi is credited with developing a method whereby variations in the frequency of the occurrence of letters could be analyzed and exploited to break ciphers (i.e. cryptanalysis by frequency analysis).[11]

Music theoryEdit

Al-Kindi was the first great theoretician of music in the Arab-Islamic world. He is known to have written fifteen treatises on music theory, but only five have survived. He added a fifth string to the ‘ud.[30] His works included discussions on the therapeutic value of music[31] and what he regarded as “cosmological connections” of music.[32]

Philosophical thoughtEdit


While Muslim intellectuals were already acquainted with Greek philosophy (especiallylogic), al-Kindi is credited with being the first real Muslim philosopher.[33] His own thought was largely influenced by the Neo-Platonic philosophy of Proclus, Plotinus and John Philoponus, amongst others, although he does appear to have borrowed ideas from other Hellenistic schools as well.[34] He makes many references to Aristotle in his writings, but these are often unwittingly re-interpreted in a Neo-Platonic framework. This trend is most obvious in areas such as metaphysics and the nature of God as a causal entity.[35] Earlier experts had suggested that he was influenced by theMutazilite school of theology, because of the mutual concern both he and they demonstrated for maintaining the singularity (tawhid) of God. However, such agreements are now considered incidental, as further study has shown that they disagreed on a number of equally important topics.[36]


According to al-Kindi, the goal of metaphysicsis the knowledge of God. For this reason, he does not make a clear distinction between philosophy and theology, because he believes they are both concerned with the same subject. Later philosophers, particularly al-Farabi and Avicenna, would strongly disagree with him on this issue, by saying that metaphysics is actually concerned with being qua being, and as such, the nature of God is purely incidental.[13]

Central to al-Kindi’s understanding of metaphysics is God’s absolute oneness, which he considers an attribute uniquely associated with God (and therefore not shared with anything else). By this he means that while we may think of any existent thing as being “one”, it is in fact both “one” and many”. For example, he says that while a body is one, it is also composed of many different parts. A person might say “I see an elephant”, by which he means “I see oneelephant”, but the term ‘elephant’ refers to a species of animal that contains many. Therefore, only God is absolutely one, both in being and in concept, lacking any multiplicity whatsoever. Some feel this understanding entails a very rigorous negative theologybecause it implies that any description which can be predicated to anything else, cannot be said about God.[36][37]

In addition to absolute oneness, al-Kindi also described God as the Creator. This means that He acts as both a final and efficient cause. Unlike later Muslim Neo-Platonicphilosophers (who asserted that the universe existed as a result of God’s existence “overflowing”, which is a passive act), al-Kindi conceived of God as an active agent. In fact, of God as the agent, because all other intermediary agencies are contingent upon Him.[38] The key idea here is that God “acts” through created intermediaries, which in turn “act” on one another – through a chain of cause and effect – to produce the desired result. In reality, these intermediary agents do not “act” at all, they are merely a conduit for God’s own action.[35] This is especially significant in the development of Islamic philosophy, as it portrayed the “first cause” and “unmoved mover” of Aristotelianphilosophy as compatible with the concept of God according to Islamic revelation.[39]


Ancient Greek philosophers such as Plato and Aristotle would become highly revered in the medieval Islamic world.

Al-Kindi theorized that there was a separate, incorporeal and universal intellect (known as the “First Intellect”). It was the first of God’s creation and the intermediary through which all other things came into creation. Aside from its obvious metaphysical importance, it was also crucial to al-Kindi’s epistemology, which was influenced by Platonic realism.[40]

According to Plato, everything that exists in the material world corresponds to certainuniversal forms in the heavenly realm. These forms are really abstract concepts such as a species, quality or relation, which apply to all physical objects and beings. For example, a red apple has the quality of “redness” derived from the appropriate universal. However, al-Kindi says that human intellects are onlypotentially able to comprehend these. This potential is actualized by the First Intellect, which is perpetually thinking about all of the universals. He argues that the external agency of this intellect is necessary by saying that human beings cannot arrive at a universal concept merely through perception. In other words, an intellect cannot understand the species of a thing simply by examining one or more of its instances. According to him, this will only yield an inferior “sensible form”, and not the universal form which we desire. The universal form can only be attained through contemplation and actualization by the First Intellect.[41]

The analogy he provides to explain his theory is that of wood and fire. Wood, he argues, is potentially hot (just as a human is potentially thinking about a universal), and therefore requires something else which is already hot (such as fire) to actualize this. This means that for the human intellect to think about something, the First Intellect must already be thinking about it. Therefore he says that the First Intellect must always be thinking about everything. Once the human intellect comprehends a universal by this process, it becomes part of the individual’s “acquired intellect” and can be thought about whenever he or she wishes.[42]

The soul and the afterlifeEdit

Al-Kindi says that the soul is a simple, immaterial substance, which is related to the material world only because of its faculties which operate through the physical body. To explain the nature of our worldly existence, he (borrowing from Epictetus) compares it to a ship which has, during the course of its ocean voyage, temporarily anchored itself at an island and allowed its passengers to disembark. The implicit warning is that those passengers who linger too long on the island may be left behind when the ship sets sail again. Here, al-Kindi displays a stoic concept, that we must not become attached to material things (represented by the island), as they will invariably be taken away from us (when the ship sets sail again). He then connects this with a Neo-Platonist idea, by saying that our soul can be directed towards the pursuit of desire or the pursuit of intellect; the former will tie it to the body, so that when the body dies, it will also die, but the latter will free it from the body and allow it to survive “in the light of the Creator” in a realm of pure intelligence.[43]

The relationship between revelation and philosophyEdit

In the view of al-Kindi, prophecy and philosophy were two different routes to arrive at the truth. He contrasts the two positions in four ways. Firstly, while a person must undergo a long period of training and study to become a philosopher, prophecy is bestowed upon someone by God. Secondly, the philosopher must arrive at the truth by his own devices (and with great difficulty), whereas the prophet has the truth revealed to him by God. Thirdly, the understanding of the prophet – being divinely revealed – is clearer and more comprehensive than that of the philosopher. Fourthly, the way in which the prophet is able to express this understanding to the ordinary people is superior. Therefore al-Kindi says the prophet is superior in two fields: the ease and certainty with which he receives the truth, and the way in which he presents it. However, the crucial implication is that the content of the prophet’s and the philosopher’s knowledge is the same. This, says Adamson, demonstrates how limited the superiority al-Kindi afforded to prophecy was.[44][45]

In addition to this, al-Kindi adopted a naturalistic view of prophetic visions. He argued that, through the faculty of “imagination” as conceived of in Aristotelian philosophy, certain “pure” and well-prepared souls, were able to receive information about future events. Significantly, he does not attribute such visions or dreams to revelation from God, but instead explains that imagination enables human beings to receive the “form” of something without needing to perceive the physical entity to which it refers. Therefore, it would seem to imply that anyone who has purified themselves would be able to receive such visions. It is precisely this idea, amongst other naturalistic explanations of prophetic miracles that al-Ghazali attacks in his Incoherence of the Philosophers.[46]

Critics and patronsEdit

While al-Kindi appreciated the usefulness of philosophy in answering questions of a religious nature, there would be many Islamic thinkers who were not as enthusiastic about its potential. But it would be incorrect to assume that they opposed philosophy simply because it was a “foreign science”. Oliver Leaman, an expert on Islamic philosophy, points out that the objections of notable theologians are rarely directed at philosophy itself, but rather at the conclusions the philosophers arrived at. Even al-Ghazali, who is famous for his critique of the philosophers, was himself an expert in philosophy andlogic. And his criticism was that they arrived at theologically erroneous conclusions. The three most serious of these, in his view, were believing in the co-eternity of the universe with God, denying the bodily resurrection, and asserting that God only has knowledge of abstract universals, not of particular things (not all philosophers subscribed to these same views).[47]

During his life, al-Kindi was fortunate enough to enjoy the patronage of the pro-MutaziliteCaliphs al-Ma’mun and al-Mu’tasim, which meant he could carry out his philosophical speculations with relative ease. In his own time, al-Kindi would be criticized for extolling the “intellect” as being the most immanent creation in proximity to God, which was commonly held to be the position of the angels.[48] He also engaged in disputations with the Mutazilites, whom he attacked for their belief in atoms.[49] But the real role of al-Kindi in the conflict between philosophers and theologians would be to prepare the ground for debate. His works, says Deborah Black, contained all the seeds of future controversy that would be fully realized in al-Ghazali’s Incoherence of the Philosophers.[50]