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{{Short description|Muslim Arab philosopher, mathematician and physician (c. 801–873)}} | |||
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{{Distinguish|Abd al-Masih ibn Ishaq al-Kindi}} | ||
{{for|the surname|al-Kindi (surname)}} | |||
{{Infobox_Philosopher | |||
{{Use dmy dates|date=June 2020}} | |||
| region = ] | |||
{{Lowercase title}} | |||
{{infobox philosopher | |||
| region = ] | |||
| era = ] | | era = ] | ||
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| image = Stamp IQ 1962 6f.jpg | ||
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| caption = al-Kindi on Iraqi stamp from 1962 | ||
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| name = al-Kindi | ||
| birth_date = {{Circa|801}} | |||
| name = Abū Yūsuf Yaʻqūb ibn Isḥāq al-Kindī ({{lang-ar|'''أبو يوسف يعقوب إبن إسحاق الكندي'''}}) | |||
| |
| birth_place = ], ] | ||
| death_date = {{Circa|873}} (aged approximately 72) | |||
| birth_place = ], ] | |||
| death_place = ], Abbasid Caliphate (now in Iraq) | |||
| death_date = c. 873 | |||
| school_tradition = {{hlist|class=nowrap|]<ref>Klein-Frank, F. ''Al-Kindi''. In Leaman, O & Nasr, H (2001). ''History of Islamic Philosophy''. London: Routledge. p 165</ref>}} | |||
| death_place = ], ] (aged 71-72) | |||
| main_interests = ], ] (]), ], ], ], ], ], ], ], ], ], ], ], ] | |||
| school_tradition = ], ], ], ] ] | |||
| notable_ideas = | |||
| main_interests = ], ], ], ], ], ], ], ], ], ] | |||
| influences = ], ], ], ], ], ], ] | |||
| influenced = ], ], ], ], ], ], ], ], ], ], ] | |||
| notable_ideas = | |||
}} | }} | ||
'''Abū Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī''' ({{IPAc-en|æ|l|ˈ|k|ɪ|n|d|i}}; {{langx|ar|أبو يوسف يعقوب بن إسحاق الصبّاح الكندي}}; {{langx|la|Alkindus}}; {{Circa|801–873 AD}}) was an Arab ] ] active as a ], ], ], and ]. Al-Kindi was the first of the ], and is hailed as the "father of ]".<ref name=Nasr137To138>{{cite book |last=Nasr |first=Seyyed Hossein |title=] |date=2006 |publisher=State University of New York |isbn=978-0-7914-6799-2 |pages=137–138}}</ref><ref>{{cite book|last=Abboud |first=Tony|title=Al-Kindi: the father of Arab philosophy|date=2006|publisher=Rosen |isbn=978-1-4042-0511-6}}</ref><ref>{{cite book|last=Greenberg |first=Yudit Kornberg |title=Encyclopedia of love in world religions |date=2008 |publisher=ABC-CLIO |isbn=978-1-85109-980-1 |volume=1 |page=405}}</ref> | |||
'''{{transl|ar|ALA|Abū Yūsuf Yaʻqūb ibn Isḥāq al-Kindī}}''' ({{lang-ar|'''أبو يوسف يعقوب إبن إسحاق الكندي'''}}) (c. 801–873 CE), also known to the ] by the ]ized version of his name '''Alkindus''', was an ] ] ]:<ref name="SEP">{{cite web|url=http://plato.stanford.edu/entries/al-kindi/|title=Stanford Encyclopedia of Philosophy: Al-Kindi|date=2006-12-01|work=Stanford Encyclopedia of Philosophy|publisher=Stanford University|accessdate=2008-08-24}}</ref> an ], ], ], ], ], ], ], ], ], ], ], ], and ].<ref name=FSTC/> Al-Kindi was the first of the Muslim ] philosophers, and is known for his efforts to introduce ] and ] to the ],<ref>Klein-Frank, F. ''Al-Kindi''. In Leaman, O & Nasr, H (2001). ''History of Islamic Philosophy''. London: Routledge. p 165</ref> and as a pioneer in ], ], ], ], ],the ], and is also known for being one of the fathers of ]. | |||
Al-Kindi was |
Al-Kindi was born in ] and educated in ].<ref>{{cite web |title=Al-Kindi biography |url=https://www-gap.dcs.st-and.ac.uk/~history/Biographies/Al-Kindi.html |website=www-groups.dcs.st-and.ac.uk|archive-url=https://web.archive.org/web/20071026091801/https://www-gap.dcs.st-and.ac.uk/~history/Biographies/Al-Kindi.html |archive-date=26 October 2007 }}</ref> He became a prominent figure in the ], and a number of ] Caliphs appointed him to oversee the translation of ] scientific and philosophical texts into the ]. This contact with "the philosophy of the ancients" (as ] was often referred to by Muslim scholars) had a profound effect on him, as he synthesized, adapted and promoted Hellenistic and ] philosophy in the ].{{sfn|Klein-Franke|2001|page=165}} He subsequently wrote hundreds of original treatises of his own on a range of subjects ranging from ], ethics, ] and ], to medicine, ],{{sfn|Corbin|1993|page=155}} mathematics, ], ] and ], and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, ] and ].{{sfn|Adamson|2005|page=33}}{{sfn|Adamson|2007|page=7}} | ||
In the field of ], al-Kindi played an important role in introducing ] to the Islamic world, and their further development into ] along with ] which eventually was adopted by the rest of the world.<ref name="st-and1">{{cite web |url=http://www-gap.dcs.st-and.ac.uk/~history/Biographies/Al-Kindi.html |title=Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi |access-date=26 October 2007 |url-status=dead |archive-url=https://web.archive.org/web/20071026091801/http://www-gap.dcs.st-and.ac.uk/~history/Biographies/Al-Kindi.html |archive-date=26 October 2007 }}</ref> Al-Kindi was also one of the fathers of ].<ref>{{cite news |title=The man who cracked the Kama Sutra code |date=4 October 2000 |url=https://www.telegraph.co.uk/news/science/science-news/4754214/The-man-who-cracked-the-Kama-Sutra-code.html |archive-url=https://ghostarchive.org/archive/20220112/https://www.telegraph.co.uk/news/science/science-news/4754214/The-man-who-cracked-the-Kama-Sutra-code.html |archive-date=12 January 2022 |url-access=subscription |url-status=live |newspaper=The Telegraph|issn=0307-1235}}{{cbignore}}</ref><ref>{{ cite book |last=Borda |first=Monica |date=2011 |title=Fundamentals in Information Theory and Coding |publisher=Springer |page=122 |quote=Al Kindi, an Arab scientist from 9th century is considered the father of cryptology, his book on this subject being, at this moment, the oldest available.}}</ref> Building on the work of ] (717–786),<ref name="LB"/> Al-Kindi's book entitled ''Manuscript on Deciphering Cryptographic Messages'' gave rise to the birth of ], was the earliest known use of ],<ref>{{cite journal |last=Broemeling |first=Lyle D. |title=An Account of Early Statistical Inference in Arab Cryptology |doi=10.1198/tas.2011.10191 |journal=The American Statistician |volume=65 |issue=4 |pages=255–257 |date=2011|s2cid=123537702 }}</ref> and introduced several new methods of breaking ciphers, notably ].<ref>{{cite web |url=https://cemse.kaust.edu.sa/stat/al-kindi-distinguished-statistics-lectures |website=Statistics at King Abdullah University of Science and Technology |title=Al-Kindi Distinguished Statistics Lectures |quote=The lectures are named after Al-Kindi (801–873 CE), a prominent figure in the House of Wisdom, whose book entitled "Manuscript on Deciphering Cryptographic Messages" is believed to be the earliest writing on statistics. In his book, Al-Kindi gave a detailed description on how to decipher encrypted messages using statistics and frequency analysis. This text arguably gave rise to the birth of both statistics and cryptanalysis.}}</ref><ref name=singh>{{cite book |last=Singh |first=Simon |author-link=Simon Singh |title=The Code Book |pages= |location=New York City |publisher=Anchor Books |date=2000 |isbn=9780385495325 |url-access=registration |url=https://archive.org/details/codebook00simo/page/14 }}</ref> He was able to create a scale that would enable doctors to gauge the effectiveness of their medication by combining his knowledge of mathematics and medicine.{{sfn|Klein-Franke|2001|page=172}} | |||
In mathematics, al-Kindi played an important role in introducing ] to the Islamic and Christian world.<ref name="www-gap.dcs.st-and.ac.uk">{{cite web |url=http://www-gap.dcs.st-and.ac.uk/~history/Biographies/Al-Kindi.html |title=Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi |accessdate=2007-01-12 |work= }}</ref> He was a pioneer in ] and ], and devised new methods of breaking ], including the ] method.<ref>Simon Singh. ''The Code Book''. p. 14-20</ref> Using his mathematical and medical expertise, he developed a scale to allow doctors to quantify the potency of their ].<ref>Klein-Franke, p172</ref> He also experimented with ].<ref name=Saoud>{{cite web |url=http://www.muslimheritage.com/uploads/Music2.pdf |title=The Arab Contribution to the Music of the Western World |accessdate=2007-01-12 |format=PDF |author=Saoud, R. |publisher=FSTC}}</ref> | |||
The central theme underpinning al-Kindi's philosophical writings is the compatibility between philosophy and other orthodox |
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 ] and ].{{sfn|Adamson|2005|page=34}} | ||
== |
==Early life== | ||
Al-Kindi was born in ] |
Al-Kindi was born in ] to an aristocratic family of the ] of the ], descended from the chieftain ], a contemporary of ].<ref>{{Cite book|url=https://books.google.com/books?id=h4fN4HEPD68C&pg=PA12|title=Al Kindi: The Father of Arab Philosophy|last=Abboud|first=Tony|date=15 January 2006|publisher=The Rosen Publishing Group, Inc|isbn=9781404205116|language=en}}</ref> The family belonged to the most prominent families of the tribal nobility of ] in the early Islamic period, until it lost much of its power following the revolt of ].<ref>{{Slaves on Horses | pages = 110–111}}</ref> His father Ishaq was the ] of ] and al-Kindi received his preliminary education there. He later went to complete his studies in Baghdad, where he was patronized by the ] ] ({{reign|813|833}}) and ] ({{reign|833|842}}). On account of his learning and aptitude for study, al-Ma'mun appointed him to the ], a recently established center for the translation of ] philosophical and scientific texts, in Baghdad. He was also well known for his beautiful ], and at one point was employed as a calligrapher by Caliph ] ({{reign|847|861}}). {{sfn|Corbin|1993|page=154}} | ||
When al-Ma'mun died, his brother, al-Mu'tasim became |
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 ] ({{reign|842|847}}), and especially of al-Mutawakkil, al-Kindi's star waned. There are various theories concerning this: some attribute al-Kindi's downfall to scholarly rivalries at the ]; 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. ], an authority on Islamic studies, says that in 873, al-Kindi died "a lonely man", in Baghdad during the reign of ] ({{reign|870|892}}). {{sfn|Corbin|1993|page=154}} | ||
After his death, al-Kindi's philosophical works quickly fell into obscurity |
After his death, al-Kindi's philosophical works quickly fell into obscurity; many were lost even to later Islamic scholars and historians. Felix Klein-Franke suggests several reasons for this: aside from the militant orthodoxy of al-Mutawakkil, the ] also destroyed countless libraries during their ]. However, he says the most probable cause of this was that his writings never found popularity amongst subsequent influential philosophers such as ] and ], who ultimately overshadowed him.{{sfn|Klein-Franke|2001|page=166}} His philosophical career peaked under al-Mu'tasim, to whom al-Kindi dedicated his most famous work, ''On First Philosophy'', and whose son Ahmad was tutored by al-Kindi. | ||
==Accomplishments== | ==Accomplishments== | ||
According to ] ] ], al-Kindi wrote at least two hundred and sixty books, contributing heavily to ] (thirty-two books), medicine and philosophy (twenty-two books each), ] (nine books), and ] (twelve books).{{sfn|Corbin|1993|pages=154–155}} Although most of his books have been lost over the centuries, a few have survived in the form of ] translations by ], 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.{{sfn|Klein-Franke|2001|pages=172–173}} | |||
Al-Kindi was a master of many different areas of thought. Although he would eventually be eclipsed by names such as al-Farabi and Avicenna, he was held to be one of the greatest ]ic philosophers of his time. The historian ] (d. 955), described him as:<ref>{{cite web |url=http://www.muslimheritage.com/day_life/default.cfm?ArticleID=370&Oldpage=1 |title=Al-Kindi, Encyclopaedic Scholar of the Baghdad 'House of Wisdom' |accessdate=2007-01-12 |work= }}</ref> | |||
===Philosophy=== | |||
<blockquote>''The best man of his time, unique in his knowledge of all the ancient sciences. He is called the Philosopher of the Arabs. His books deal with different sciences, such as logic, philosophy, geometry, arithmetic, astronomy etc. We have connected him with the natural philosophers because of his prominence in Science.''</blockquote> | |||
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 ] (Bayt al-Hikma), an institute of translation and learning patronized by the ] Caliphs, in Baghdad.{{sfn|Corbin|1993|page=154}} 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 ], ], and ] might not have been possible.{{sfn|Adamson|2005|page=32-33}} | |||
In his writings, one of al-Kindi's central concerns was to demonstrate the compatibility between philosophy and ] on the one hand, and revealed or ] 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 ] and (especially) ] thought into an Islamic philosophical framework. This was an important factor in the introduction and popularization of Greek philosophy in the Muslim intellectual world.{{sfn|Klein-Franke|2001|pages=166–167}} | |||
The Italian Renaissance scholar ] (1501–1575) considered him one of the twelve greatest minds of the Middle Ages.<ref>George Satron. ''Introduction to the History of Science''.</ref> According to Ibn al-Nadim, al-Kindi wrote at least two hundred and sixty books, contributing heavily to ] (thirty-two books), medicine and philosophy (twenty-two books each), ] (nine books), and ] (twelve books).<ref>Corbin, pp 154–155</ref> 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 ] translations by ], 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.<ref>Klein-Franke, pp 172–173</ref> '']'', a paraphrase of parts of ]' '']'' along with ]'s commentary, seems to have been edited by Al-Kindi.<ref>{{citation|first=Peter|last=Adamson|title=Before Essence and Existence: al-Kindi's Conception of Being|journal=]|volume=40|issue=3|year=2002|pages=297–312|url=http://www.muslimphilosophy.com/ip/art/jhp40-3.htm|accessdate=2008-08-21|doi=10.1353/hph.2002.0043}}</ref> | |||
===Astronomy=== | |||
===Astrology, astronomy, and cosmology=== | |||
] | |||
In ] and ], al-Kindi followed ]'s view of the solar system with ] of a series of concentric spheres, in which the known heavenly bodies (the ], ], ], the ], ], ], and the ]s) 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), and (according to al-Kindi) the appearance and manner of people varies according to the arrangement of heavenly bodies situated above their homeland.<ref>Adamson 2005, p.42</ref> | |||
Al-Kindi took his view of the solar system from ], 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 ] 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.{{sfn|Adamson|2005|page=42}} | |||
Al-Kindi discussed the 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 ], 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 in 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 ].<ref>Adamson 2005, p.43</ref> | |||
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 in the treatise ''On Rays'' (''De radiis'') is that the planets exercise their influence in straight lines; but this treatise, written by a Latin author, probably around the middle of the 13th century, is apocryphal.<ref>{{cite journal |last1=Matton |first1=Sylvain |title=An Irradiation of Latin Grammarians, or The De radiis is not by al-Kindī |journal=Magic, Ritual, and Witchcraft |date=Winter 2023 |volume=17 |issue=3 |pages=437–455 |doi=10.1353/mrw.2023.0005|s2cid=258054985 }}</ref> In each of these, two fundamentally different views of physical interaction are presented; action by contact and action at a distance. This dichotomy is duplicated in his writings on ].{{sfn|Adamson|2005|page=43}} | |||
In ], al-Kindi maintained the traditional ] according to which heavy bodies, such as the ], move downward toward the centre and light bodies, such as ], move upward away from the centre.<ref>George N. Atiyeh, ''Al-Kindi: Philosopher of the Arabs'', (Rawalpinidi: Islamic Research Institute, 1966), p. 85</ref> | |||
Some of the notable astrological works by al-Kindi include:<ref>{{cite book |first=Benjamin N. |last=Dykes |title=The Forty Chapters of Al-Kindī: Traditional Horary and Electional Astrology |location=Minneapolis |publisher=Cazimi Press |date=2011 |pages=5–6 }}</ref> | |||
===Chemistry and perfumery=== | |||
*''The Book of the Judgement of the Stars'', including ''The Forty Chapters'', on questions and elections. | |||
As an advanced ], al-Kindi was the first to oppose the practice of ]; he debunked the myth that simple, base ]s could be ] into precious metals such as ] or ].<ref>Klein-Franke, p174</ref> He wrote two treatises on the refutation of alchemy: ''Warning against the Deceptions of the Alchemists'' and ''Refutation of the Claim of Those Who Claim the Artificial Fabrication of Gold and Silver''.<ref name=Plinio-17>Plinio Prioreschi, "Al-Kindi, A Precursor Of The Scientific Revolution", ''Journal of the International Society for the History of Islamic Medicine'', 2002 (2): 17-19 .</ref> | |||
*''On the Stellar Rays'' (spurious) | |||
*Several epistles on weather and meteorology, including ''De mutatione temporum'', ("On the Changing of the Weather"). | |||
*Treatise 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 Planets''. | |||
===Optics=== | |||
Building on the work of ] (Geber), the isolation of ] (]) as a relatively pure ] was first achieved by al-Kindi. He was the first to unambiguously describe the production of pure ] from the ] of ].<ref>{{cite web |url=http://www.history-science-technology.com/Notes/Notes%207.htm |title=Alcohol and the Distillation of Wine in Arabic Sources |accessdate=2008-03-29 |last=Hassan |first=Ahmad Y |authorlink=Ahmad Y Hassan |work=History of Science and Technology in Islam}}</ref> | |||
], Medieval manuscripts, MS R.15.17 (937).]] | |||
Al-Kindi was the first major writer on ] since antiquity. ] placed him in the first rank after ] as a writer on the topic.<ref>{{cite book|last1=Deming|first1=David|title=Science and Technology in World History, Volume 2: Early Christianity, the Rise of Islam and the Middle Ages|date=2012|publisher=McFarland|pages=92|language=en}}</ref> In the apocryphal work known as ''De radiis stellarum'', is developed the theory "that everything in the world ... emits rays in every direction, which fill the whole world."<ref>{{cite book |first=David C. |last=Lindberg |title=Theories of Vision from al-Kindi to Kepler |location=Chicago |publisher=University of Chicago |date=1976 |page=19 |oclc=463202962}}</ref> This theory of the active power of rays had an influence on later scholars such as ], ] and ].<ref>{{cite journal |first=David C. |last=Lindberg |journal=] |volume=62 |issue=4 |date=Winter 1971 |pages=469–489 |doi=10.1086/350790 |title=Alkindi's Critique of Euclid's Theory of Vision|pmid=4948770 |s2cid=40895875 }}</ref> | |||
Two major theories of ] appear in the writings of al-Kindi: ] and ]ean. 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. | |||
Al-Kindi invented a wide variety of ] and ] products, and is considered the father of the perfume industry. He carried out extensive ] and ]s in combining various ]s and other sources to produce a variety of ] products. He elaborated a vast number of ]s for a wide range of perfumes, ] and ]. His work in the laboratory is reported by a witness who said, "I received the following description, or recipe, from Abu Yusuf Ya'qub b. Ishaq al-Kindi, and I saw him making it and giving it an addition in my presence". The writer goes on in the same section to speak of the preparation of a perfume called ''ghaliya'', which contained ], ] and other ingredients, and reveals a long list of technical names of ]s and ].<ref name=FSTC/> | |||
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. For this reason, al-Kindi considered the latter preponderant.{{sfn|Adamson|2005|page=45}} | |||
The ''Kitab Kimiya' al-'Itr'' (''Book of the Chemistry of Perfume'') written by al-Kindi contains recipes for ], ]s, ]tic waters, and substitutes or imitations of costly drugs. He also provided the earliest recipe for the production of ].<ref name=FSTC/> | |||
Al-Kindi's primary optical treatise "De aspectibus" was later translated into Latin. This work, along with ]'s ] and the Arabic translations of ] and ], were the main Arabic texts to affect the development of optical investigations in Europe, most notably those of ], ] and ].<ref>{{cite book |last=Szulakowska |first=Urszula |date=2000 |title=The Alchemy of Light: Geometry and Optics in Late Renaissance Alchemical Illustration |publisher=Brill|page=29 |quote=In the West, optics was developed by fourteenth century scholastics such as Bacon, Witelo, Ockham and Pecham following Arabian models, in particular, those of Alhazen's Optics and Al-kindi's De radiis stellarum.}}</ref> | |||
] by ].]] | |||
===Medicine=== | |||
Al-Kindi is also noted for his experiments on Botanical and chemical work such as: ''A Treatise on the Artificial Production of Foodstuffs without their Elements'', which describes the same kind of experiment with a different range of material. The work, was for theoretical purposes, and the experiments might have been made for the relief of ]. | |||
There are more than thirty treatises attributed to al-Kindi in the field of medicine, in which he was chiefly influenced by the ideas of ].{{sfn|Prioreschi|2002}} His most important work in this field is probably '']'', 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 a drug, and a system (based on the phases of the moon) that would allow a doctor to determine in advance the most critical days of a patient's illness.{{sfn|Klein-Franke|2001|page=172}} According to Plinio Prioreschi, this was the first attempt at serious quantification in medicine.{{sfn|Prioreschi|1996|page=230}} | |||
===Chemistry=== | |||
===Cryptography and mathematics=== | |||
Al-Kindi denied the possibility of transmuting base metals into precious metals such as gold and silver, a position that was later attacked by the Persian alchemist and physician ] ({{Circa|865|925}}).{{sfn|Klein-Franke|2001|pages=173-174}} | |||
Al-Kindi was a pioneer in ], especially ]. He gave the first known recorded explanation of cryptanalysis in ''A Manuscript on Deciphering Cryptographic Messages''. In particular, he is credited with developing the ] method whereby variations in the frequency of the occurrence of letters could be analyzed and exploited to break ]s (i.e. cryptanalysis by frequency analysis).<ref>Simon Singh. The Code Book. p. 14-20</ref> This was detailed in a text recently rediscovered in the Ottoman archives in Istanbul, ''A Manuscript on Deciphering Cryptographic Messages'', which also covers methods of cryptanalysis, encipherments, cryptanalysis of certain encipherments, and statistical analysis of letters and letter combinations in Arabic.<ref>{{cite web |url=http://www.muslimheritage.com/topics/default.cfm?ArticleID=372 |title= Al-Kindi, Cryptgraphy, Codebreaking and Ciphers |accessdate=2007-01-12 |work= }}</ref> Al-Kindi also had knowledge of ]s centuries before ]. Al-Kindi's book also introduced the classification of ciphers, developed Arabic ] and ], and described the use of several statistical techniques for cryptoanalysis. This book apparently antedates other cryptology references by several centuries, and it also predates writings on ] and ] by ] and ] by nearly eight centuries.<ref>] (April 1992), "The origins of cryptology: The Arab contributions”, '']'' '''16''' (2): 97–126</ref> | |||
One work attributed to al-Kindi, variously known as the ''Kitāb al-Taraffuq fī l-ʿiṭr'' ("The Book of Gentleness on Perfume") or the ''Kitāb Kīmiyāʾ al-ʿiṭr wa-l-taṣʿīdāt'' ("The Book of the Chemistry of Perfume and Distillations"), contains one of the earliest known references to the distillation of wine.<ref>{{cite book|last1=al-Hassan|first1=Ahmad Y.|author-link=Ahmad Y. al-Hassan|year=2001|chapter=Alchemy, chemistry and chemical technology|editor-last=al-Hassan |editor-first=Ahmad Y.|title=Science and Technology in Islam: Technology and Applied Sciences|pages=41–84|publisher=UNESCO |isbn=9789231038310}} pp. 65-69; {{cite book|last1=al-Hassan|first1=Ahmad Y.|author-link=Ahmad Y. al-Hassan|year=2009|chapter=Alcohol and the Distillation of Wine in Arabic Sources from the 8th Century|title=Studies in al-Kimya': Critical Issues in Latin and Arabic Alchemy and Chemistry|location=Hildesheim|publisher=Georg Olms Verlag|pages=283–298}} (same content also available on ). See also {{cite book|last1=Garbers|first1=Karl|year=1948|title=Kitāb Kīmiyā' al-'Iṭr Wat-Taṣ'īdāt: Buch über die Chemie des Parfüms und die Destillationen von Ya'qūb b. Isḥāq al-Kindī. Ein Beitrag zur Geschichte der arabischen Parfümgeschichte und Drogenkunde aus de 9. Jahrh.|volume=P.C. Abhandlungen für die Kunde des Morgenlandes, 30|location=Leipzig|publisher=Brockhaus}}.</ref> The work also describes the ] process for extracting ]s, and provides recipes for 107 different kinds of perfumes.{{sfn|al-Hassan|2001|page=69}} | |||
Al-Kindi authored works on a number of other important ], 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.<ref name="www-gap.dcs.st-and.ac.uk"/> 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 ] 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 ] is a mathematical and logical absurdity.<ref>{{cite web |url=http://www.muslimphilosophy.com/ma/eip/ma-k-mp.pdf |title= Al-Kindi's Mathematical Metaphysics |accessdate=2007-01-12 |format=PDF |author= Al-Allaf, M }}</ref> | |||
===Mathematics=== | |||
===Environmentalism and meteorology=== | |||
Al-Kindi authored works on a number of important mathematical subjects, including arithmetic, geometry, the Hindu numbers, the harmony of numbers, lines and multiplication with numbers, relative quantities, measuring proportion and time, and numerical procedures and cancellation.<ref name="st-and1"/> He also wrote four volumes, ''On the Use of the Hindu Numerals'' ({{langx|ar|كتاب في استعمال الأعداد الهندية}} ''Kitāb fī Isti`māl al-'A`dād al-Hindīyyah'') which contributed greatly to diffusion of the Hindu 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 ] is a mathematical and logical absurdity.<ref>{{cite web |url=http://www.muslimphilosophy.com/ma/eip/ma-k-mp.pdf |title= Al-Kindi's Mathematical Metaphysics |access-date=12 January 2007 |author= Al-Allaf, M | archive-url= https://web.archive.org/web/20070107031711/http://www.muslimphilosophy.com/ma/eip/ma-k-mp.pdf| archive-date= 7 January 2007 | url-status= live}}</ref> | |||
The earliest known work concerned with ] and ] was an ] written by al-Kindi. His writings, along with the works of his successors (], ], ], ], ], Avicenna, ], Ibn Jumay, ], ], Ibn al-Quff and ]), covered a number of subjects related to pollution such as ], ], ], ] mishandling, and ] of certain localities.<ref>L. Gari (2002), "Arabic Treatises on Environmental Pollution up to the End of the Thirteenth Century", ''Environment and History'' '''8''' (4), pp. 475-488.</ref> | |||
===Cryptography=== | |||
Al-Kindi wrote a treatise on ] entitled ''Risala fi l-Illa al-Failali l-Madd wa l-Fazr'' (''Treatise on the Efficient Cause of the Flow and Ebb''), in which he presents an argument on ]s which "depends on the changes which take place in bodies owing to the rise and fall of ]."<ref name=FSTC>{{cite web|title=Al-Kindi|url=http://www.muslimheritage.com/day_life/default.cfm?ArticleID=691&Oldpage=1|publisher=FSTC Limited|accessdate=2008-08-21}}</ref> He describes the following clear and precise ] experiment in order to prove his argument:<ref name=Plinio-17/> | |||
] by ].]] | |||
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 ]).<ref name=singh/> His book on this topic is ''Risāla fī Istikhrāj al-Kutub al-Mu'ammāh'' (رسالة في استخراج الكتب المعماة; literally: ''On Extracting Obscured Correspondence'', more contemporarily: ''On Decrypting Encrypted Correspondence''). In his treatise on cryptanalysis, he wrote:<blockquote>One way to solve an encrypted message, if we know its language, is to find a different plaintext of the same language long enough to fill one sheet or so, and then we count the occurrences of each letter. We call the most frequently occurring letter the "first", the next most occurring letter the "second", the following most occurring letter the "third", and so on, until we account for all the different letters in the plaintext sample. Then we look at the cipher text we want to solve and we also classify its symbols. We find the most occurring symbol and change it to the form of the "first" letter of the plaintext sample, the next most common symbol is changed to the form of the "second" letter, and the following most common symbol is changed to the form of the "third" letter, and so on, until we account for all symbols of the cryptogram we want to solve.<ref>{{Cite book |url=https://books.google.com/books?id=GbKyAAAAQBAJ |title=The Mathematics of Encryption: An Elementary Introduction |first1=Margaret |last1=Cozzens |first2=Steven J. |last2=Miller |publisher=American Mathematical Society |year=2013 |isbn=978-0821883211|page=5}}</ref></blockquote> | |||
{{quote|One can also observe by the senses... how in consequence of extreme cold air changes into water. To do this, one takes a glass bottle, fills it completely with snow, and closes its end carefully. Then one determines its weight by weighing. One places it in a container... which has previously been weighed. On the surface of the bottle the air changes into water, and appears upon it like the drops on large porous pitchers, so that a considerable amount of water gradually collects inside the container. One then weighs the bottle, the water and the container, and finds their weight greater than previously, which proves the change. Some foolish persons are of opinion that the snow exudes through the glass. This is impossible. There is no process by which water or snow can be made to pass through glass.<ref name=FSTC/>}} | |||
Al-Kindi was influenced by the work of ] (717–786), who wrote the ''Book of Cryptographic Messages'', which contains the first use of ] to list all possible ] words with and without vowels.<ref name="LB">{{cite journal|last=Broemeling|first=Lyle D.|title=An Account of Early Statistical Inference in Arab Cryptology|journal=The American Statistician|date=1 November 2011|volume=65|issue=4|pages=255–257|doi=10.1198/tas.2011.10191|s2cid=123537702}}</ref> | |||
===Medicine=== | |||
{{see|De Gradibus}} | |||
===Meteorology=== | |||
There are more than thirty treatises attributed to al-Kindi in the field of ], in which he was partly influenced by the ideas of ],<ref>P. Prioreschi. Al-Kindi, A Precursor of the Scientific Revolution</ref> and partly by his own personal experience and other ] in his time. | |||
In a treatise entitled as ''Risala fi l-Illa al-Failali l-Madd wa l-Fazr'' (''Treatise on the Efficient Cause of the Flow and Ebb''), al-Kindi presents a theory on ]s which "depends on the changes which take place in bodies owing to the rise and fall of temperature."{{sfn|Prioreschi|2002|page=17}} In order to support his argument, he gave a description of a scientific experiment as follows: | |||
<blockquote>One can also observe by the senses... how in consequence of extreme cold air changes into water. To do this, one takes a glass bottle, fills it completely with snow, and closes its end carefully. Then one determines its weight by weighing. One places it in a container... which has previously been weighed. On the surface of the bottle the air changes into water, and appears upon it like the drops on large porous pitchers, so that a considerable amount of water gradually collects inside the container. One then weighs the bottle, the water and the container, and finds their weight greater than previously, which proves the change. Some foolish persons are of opinion that the snow exudes through the glass. This is impossible. There is no process by which water or snow can be made to pass through glass.</blockquote> | |||
Al-Kindi's most important work in this field is probably '']'', in which he demonstrates the application of mathematics and ] to medicine, particularly in the field of pharmacology. For example, he developed a mathematical scale to quantify the strength of a ] and a system, based on the phases of the ], that would allow a doctor to determine in advance the most ] of a ]'s ].<ref>Klein-Franke, p. 172</ref> | |||
In explaining the natural cause of the ], and the difference for its directions based on time and location, he wrote:<ref>{{cite book |last1=Al-Jubouri |first1=I. M. N. |title=History of Islamic Philosophy: With View of Greek Philosophy and Early History of Islam |date=2004 |publisher=Authors on Line Ltd |isbn=9780755210114 |url=https://books.google.com/books?id=3xJjNG5CNdwC&pg=PA213|language=en}}</ref> | |||
In his ''Treatise on Diseases Caused by Phlegm'', he provided the first scientific explanation and treatment for ]:<ref>Plinio Prioreschi, "Al-Kindi, A Precursor Of The Scientific Revolution", ''Journal of the International Society for the History of Islamic Medicine'', 2002 (2): 17-19 .</ref> | |||
<blockquote>When the sun is in its northern declination northerly places will heat up and it will be cold towards the south. Then the northern air will expand in a southerly direction because of the heat due to the contraction of the southern air. Therefore most of the summer winds are merits and most of the winter winds are not.</blockquote> | |||
{{quote|When the ] melts and changes to a bad irritant quality, it goes forth and ascends to the brain from a certain direction, then it sinks down through the principal veins towards the heart, and by its irritant quality it deranges the place of sense, thought and recollection in the brain. It passes through the veins towards the heart, and if the natural heat whose source is the heart is strong enough to dissolve it, it does so, and what happens as a consequence is epilepsy (''sar''). For the parts of the brain which we have mentioned, becoming injured, are overcome and cease to function. The disturbance which we see in the (patient’s) body is owing to the conflict of the natural (heat) with the affection. When it prevails over it, it attacks and dissolves it. This is the meaning of the foam which is seen at the (patient’s) mouth. When this occurs, his recovery is near.}} | |||
In his ''Aqrabadhin'' (''Medical Formulary''), he describes many ] preparations, including simple drugs derived mostly from ] sources as well as ] and ] sources.<ref>Plinio Prioreschi, "Al-Kindi, A Precursor Of The Scientific Revolution", ''Journal of the International Society for the History of Islamic Medicine'', 2002 (2): 17-19 .</ref> | |||
The ''Kitab Kimiya' al-'Itr'' (''Book of the Chemistry of Perfume'') written by al-Kindi contains recipes for ]s and substitutes or imitations of costly ]s.<ref name=FSTC/> | |||
===Music theory=== | ===Music theory=== | ||
Al-Kindi was the first great theoretician of music in the Arab-Islamic world.Al-Kendi was the first to use musical notation, a music writing system, to write down music. He named his musical notes using literal syllables instead of letters, a process called solmization. He is known to have written fifteen treatises on ], but only five have survived. He added a fifth string to the ].<ref>{{cite book |title=Cultural Sociology of the Middle East, Asia, and Africa: An Encyclopedia |editor1-first=Andrea L. |editor1-last=Stanton |editor2-first=Peter J. |editor2-last=Seybolt |editor3-first=Edward |editor3-last=Ramsamy |editor4-first=Carolyn M. |editor4-last=Elliott |date=2012 |publisher=] |isbn=978-1412981767 |page=87}}</ref> His works included discussions on the ]<ref>{{cite book |last=Shehadi |first=Fadlou |title=Philosophies of Music in Medieval Islam |date=1995 |publisher=Brill |location=Leiden |isbn=978-9004101289 |page=35}}</ref> and what he regarded as "cosmological connections" of music.<ref>{{cite book |last=Turner |first=Howard R. |title=Science in Medieval Islam: An Illustrated Introduction |url=https://books.google.com/books?id=3VfY8PgmhDMC |url-access=registration |date=28 July 2010| publisher=University of Texas Press |isbn=978-0292781498 |edition=3rd pbk. print. |page=}}</ref> | |||
Al-Kindi was the first great theoretician of ]. He proposed adding a fifth string to the ] and discussed the cosmological connotations of music. He surpassed the achievement of the ]ians in using the alphabetical annotation for one eighth. He published fifteen treatises on ], but only five have survived. In one of his treaties the word ''musiqia'' was used for the first time in Arabic, which today means music in Arabic, Persian, Turkish, English and several other languages in the Islamic world.<ref name=Saoud/> | |||
==Philosophical thought== | |||
===Philosophy and logic=== | |||
His greatest contribution to the development of ] was his efforts to make ] and ] both accessible and acceptable to a Muslim audience. Al-Kindi carried out this mission from the ], an institute of translation and learning patronized by the ] Caliphs, in Baghdad.<ref name=Corbin154/> 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 ] might not have been possible.<ref>Adamson 2005, pp 32–33</ref> | |||
In his writings, one of al-Kindi's central concerns was to demonstrate the compatibility between philosophy and ] on the one hand, and revealed or ] 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. While his philosophical approach was not always original, and was even considered clumsy by later thinkers, he successfully incorporated ] and ] thought into an Islamic philosophical framework. This was an important factor in the introduction and popularization of Greek philosophy in the Muslim intellectual world.<ref>Klein-Franke, pp 166–167</ref> | |||
Most early writers on ] during the 8th and 9th centuries produced commentaries on ]. The first original Arabic writings on logic were produced by al-Kindi, who produced a summary on earlier logic up to his time.<ref>{{cite web|author=Randall R. Dipert|title=History of logic|url=http://www.britannica.com/ebc/article-65928|publisher='']''|accessdate=2008-08-21}}</ref> | |||
===Philosophy of science=== | |||
Al-Kindi made important contributions to the ] and the development of ]ology. Like his Arab predecessor ], al-Kindi placed a strong emphasis on experimentation, and in addition, he introduced a new emphasis on ]. He also wrote the following on his view of ]:<ref name=Plinio-17/> | |||
{{quote|We must not hesitate to recognize the ] and to accept it no matter what is its origin, no matter if it comes to us from the ancients or from foreign people... My purpose is first to write down all that the ancients have left us on a given topic and then, using the Arabic tongue and taking into account the customs of our time and our capacities, to complete what they have not fully expressed.}} | |||
Though al-Kindi held ancient authorities (such as Aristotle) in high regard, he often criticized them for making claims regarding ] without providing any ] proof, nor any ] or ]. In many instances, al-Kindi used experiments and ] methods to verify many of his own theories, as he recognized the importance of direct ] and ] as a source of scientific knowledge. He also often invented specific laboratory ] in order to carry out his experiments.<ref name=FSTC/> | |||
===Physics=== | |||
Two major ] appear in the writings of al-Kindi; ] and ]ian. 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 depends upon mathematically describable "rays" that reach out in straight lines from the eye to touch the object of vision. 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, Euclidian 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.<ref>Adamson 2005, p45</ref> | |||
In his ''Kitab al-Shu'a'at'' (''Book of the Rays''), al-Kindi wrote the following criticism on ] for reporting how "ships were set aflame by burning mirrors during a naval battle" without ]:<ref name=FSTC/> | |||
{{quote|Anthemius should not have accepted information without proof... He tells how to construct a mirror from which twenty four rays are reflected on a single point, without showing how to establish where the rays unite at a given distance from the middle of the mirror's surface. We, on the other hand, have described this with as much evidence as our ability permits, furnishing what was missing, for he has not mentioned a definite distance.}} | |||
Al-Kindi also described a ]. He demonstrated that "light from the right side of the flame will pass through the aperture and end up on the left side of the screen, while light from the left side of the flame will pass through the aperture and end up on the right side of the screen."<ref name=Steffens>Bradley Steffens (2006), ''Ibn al-Haytham: First Scientist'', , Morgan Reynolds Publishing, ISBN 1-59935-024-6</ref> | |||
===Psychology=== | |||
As an ], al-Kindi was a pioneer in ]. He was the first to use the method of experiment in psychology, which led to his discovery that ] is proportionate to the ].<ref>{{citation|first=Muhammad|last=Iqbal|author-link=Muhammad Iqbal|title=]|chapter=The Spirit of Muslim Culture|url=http://www.allamaiqbal.com/works/prose/english/reconstruction|accessdate=2008-01-25}}</ref> He was also the earliest to realize the ] value of music and attempted to cure a ] boy using ].<ref name=Saoud/> | |||
He also dealt with psychology in several other treatises: ''On Sleep and Dreams'' (a treatise on ]), ''First Philosophy'', and ''Eradication of Sorrow''. In the latter, he described ] as "a spiritual (]ani) grief caused by loss of loved ones or personal belongings, or by | |||
failure in obtaining what one lusts after" and then added: "If causes of pain are discernible, the cures can be found." He recommended that "if we do not tolerate losing or dislike being deprived of what is dear to us, then we should seek after riches in the world of the ]. In it we should treasure our precious and cherished gains where they can never be dispossessed...for that which is owned by our senses could easily be taken away from us." He also stated that "sorrow is not within us we bring it upon ourselves." He developed ] methods to combat ] and discussed the intellectual operations of human beings.<ref>{{Citation |first=Amber |last=Haque |year=2004 |title=Psychology from Islamic Perspective: Contributions of Early Muslim Scholars and Challenges to Contemporary Muslim Psychologists |journal=Journal of Religion and Health |volume=43 |issue=4 |pages=357–377 |doi=10.1007/s10943-004-4302-z}}</ref> | |||
==Philosophical thought== | |||
===Influences=== | ===Influences=== | ||
While Muslim intellectuals were already acquainted with Greek philosophy (especially ]), al-Kindi is credited with being the first real Muslim ''philosopher''. |
While Muslim intellectuals were already acquainted with Greek philosophy (especially ]), al-Kindi is credited with being the first real Muslim ''philosopher''.{{sfn|Klein-Franke|2001|page=165}} His own thought was largely influenced by the Neo-Platonic philosophy of ], ] and ], amongst others, although he does appear to have borrowed ideas from other Hellenistic schools as well.{{sfn|Adamson|2005|page=37}} He makes many references to ] 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.{{sfn|Adamson|2005|page=36}} Experts have suggested that he was influenced by the ] school of theology, because of the mutual concern both he and they demonstrated for maintaining the singularity (]) of God. A minority view however holds that such agreements are considered incidental.{{sfn|Corbin|1993|page=155}} | ||
===Metaphysics=== | ===Metaphysics=== | ||
According to al-Kindi, the goal of ] is |
According to al-Kindi, the goal of ] is 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 ] and ], 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.{{sfn|Adamson|2005|page=34}} | ||
Central to al-Kindi's understanding of metaphysics is God's ], 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 ''one'' elephant", 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. |
Central to al-Kindi's understanding of metaphysics is God's ], 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 ''one'' elephant", 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 ] because it implies that any description which can be predicated to anything else, cannot be said about God.{{sfn|Corbin|1993|page=155}}{{sfn|Adamson|2005|page=35}} | ||
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 ] philosophers (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. |
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 ] philosophers (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.{{sfn|Klein-Franke|2001|page=167}} 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.{{sfn|Adamson|2005|page=36}} This is especially significant in the development of Islamic philosophy, as it portrayed the "first cause" and "unmoved mover" of ] philosophy as compatible with the concept of God according to Islamic revelation.{{sfn|Adamson|2005|page=39}} | ||
===Epistemology=== | |||
However, in contrast to ancient Greek philosophers such as Aristotle who believed that the universe had an infinite past with no beginning, Al-Kindi believed that the universe has a ] with a beginning. This view was inspired by the creation doctrine shared by the three ]: ], ] and ]. The ], ], presented the first such argument against the ancient Greek notion of an infinite past. Philoponus' logic was adopted by many, most notably; Al-Kindi, ] (Saadia ben Joseph) and Al-Ghazali (Algazel). They used two logical arguments against an infinite past, the first being the "argument from the impossibility of the existence of an actual infinite", which states:<ref name=Craig>{{citation|title=Whitrow and Popper on the Impossibility of an Infinite Past|first=William Lane|last=Craig|journal=The British Journal for the Philosophy of Science|volume=30|issue=2|date=June 1979|pages=165–170 |doi=10.1093/bjps/30.2.165}}</ref> | |||
] and ] were highly respected 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 ], which was influenced by ].{{sfn|Klein-Franke|2001|page=168}} | |||
:"An actual infinite cannot exist." | |||
:"An infinite temporal regress of events is an actual infinite." | |||
:"{{Unicode|∴}} An infinite temporal regress of events cannot exist." | |||
According to Plato, everything that exists in the material world corresponds to certain ] 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 only ''potentially'' 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.{{sfn|Adamson|2005|pages=40–41}} | |||
The second argument, the "argument from the impossibility of completing an actual infinite by successive addition", states:<ref name=Craig/> | |||
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.{{sfn|Adamson|2005|page=40}} | |||
:"An actual infinite cannot be completed by successive addition." | |||
:"The temporal series of past events has been completed by successive addition." | |||
:"{{Unicode|∴}} The temporal series of past events cannot be an actual infinite." | |||
===The soul and the afterlife=== | |||
Both arguments were adopted by later Christian philosophers and theologians, and the second argument in particular became more famous after it was adopted by ] in his thesis of the first antimony concerning ].<ref name=Craig/> | |||
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 ]) 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 ] 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.{{sfn|Adamson|2005|pages=41–42}} | |||
===The relationship between revelation and philosophy=== | |||
===Epistemology=== | |||
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.{{sfn|Adamson|2005|page=46-47}}{{sfn|Corbin|1993|page=156}} | |||
] | |||
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 ], which was influenced by ].<ref>Klein-Frank, p168</ref> | |||
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 ] attacks in his ''Incoherence of the Philosophers''.{{sfn|Adamson|2005|page=47}} | |||
According to Plato, everything that exists in the material world corresponds to certain ] 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 only ''potentially'' 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.<ref>Adamson 2005, p40-41</ref> | |||
===Critics and patrons=== | |||
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.<ref>Adamson 2005, p40</ref> | |||
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". ], 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 ], who is famous for his critique of the philosophers, was himself an expert in philosophy and ]. 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).<ref>{{cite book |last=Leaman |first=Oliver |date=1999 |title=A Brief Introduction to Islamic Philosophy |publisher=Polity Press |page= |isbn=978-0-7456-1961-3 |url=https://archive.org/details/briefintroductio0000leam/page/21 }}</ref> | |||
During his life, al-Kindi was fortunate enough to enjoy the patronage of the <nowiki>pro-</nowiki>] Caliphs ] and ], 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.<ref>Black, p168{{full citation needed|date=December 2018}}</ref> He also engaged in disputations with certain Mutazilites, whom he attacked for their belief in atoms, as not all Mutazilites accepted the belief of atomism.<ref>Black, p169{{full citation needed|date=December 2018}}</ref> 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 ], contained all the seeds of future controversy that would be fully realized in al-Ghazali's ''Incoherence of the Philosophers''.<ref>Black, p171{{full citation needed|date=December 2018}}</ref> | |||
===The soul and the afterlife=== | |||
Al-Kindi believed 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 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 ] 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 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.<ref>Adamson 2005, p41-42</ref> | |||
==Legacy== | |||
Al-Kindi further wrote: | |||
Al-Kindi was a master of many different areas of thought and was held to be one of the greatest philosophers. His influence in the fields of physics, mathematics, medicine, philosophy, and music were far-reaching and lasted for several centuries. ] in his {{transliteration|ar|]}} praised al-Kindi and his work stating: | |||
<blockquote>The best man of his time, unique in his knowledge of all the ancient sciences. He is called the Philosopher of the Arabs. His books deal with different sciences, such as logic, philosophy, geometry, arithmetic, astronomy, etc. We have connected him with the natural philosophers because of his prominence in Science.<ref>{{cite web |title=Al-Kindi {{!}} Muslim Heritage|url=http://www.muslimheritage.com/article/al-kindi |website=muslimheritage.com |date=6 May 2007 |language=en}}</ref></blockquote> | |||
Al-Kindi's major contribution was his establishment of philosophy in the Islamic world and his efforts in trying to harmonize the philosophical investigation along with the Islamic theology and creed. The philosophical texts which were translated under his supervision would become the standard texts in the ] for centuries to come, even after his influence has been eclipsed by later Philosophers.<ref>{{cite book |last1=Adamson |first1=Peter |title=Al-Kindi – The Stanford Encyclopedia of Philosophy|chapter=Al-Kindi |url=https://plato.stanford.edu/entries/al-kindi/ |publisher=Metaphysics Research Lab, Stanford University |date=2018}}</ref> | |||
{{quote|Our residence in this phenomenal world is transitory; it is a journey towards the eternal one. The most miserable man, is he who prefers for himself the material above the spiritual, for the material, apart from its ephemeral nature, obstructs our passage to the spiritual world. Man should not `disregard any means to protect himself against all human vices, and he should seek to rise to the highest ends of human virtues..., that is, to the knowledge by means of which we protect ourselves against spiritual and bodily disease, and acquire the human virtues in whose very essence goodness is grounded.<ref name=FSTC/>}} | |||
Al-Kindi was also an important figure in ]. Several of his books got translated into Latin influencing Western authors like ] and ]. The Italian Renaissance scholar ] (1501–1575) considered him one of the twelve greatest minds.<ref>{{cite book |last1=Sarton |first1=George |title=Introduction to the History of Science |date=1927 |publisher=Carnegie Institution of Washington |url=https://books.google.com/books?id=A_MUAAAAIAAJ&q=%22twelve+greatest+minds%22+al-kindi}}</ref> | |||
===The relationship between revelation and philosophy=== | |||
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.<ref>Adamson 2005, p46-47</ref><ref>Corbin, p156</ref> | |||
In 1986, the ] inaugurated the ] in the ] district of ], ]. | |||
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 '']''.<ref>Adamson 2005, p47</ref> | |||
== |
==References== | ||
{{reflist|colwidth=30em}} | |||
While al-Kindi appreciated the usefulness of philosophy in answering questions of a religious nature, there were many Islamic thinkers who were not as enthusiastic about the use of philosophy. However, it would be incorrect to assume that they opposed philosophy simply because it was a "foreign science". ], 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 (famous for his critique of the philosophers, '']''), was himself an expert in philosophy and ]. Al-Ghazali's criticized the philosophers not for their methods, but for arriving 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.<ref>Leaman, O. (1999). ''A Brief Introduction to Islamic Philosophy'' Polity Press. p21.</ref> | |||
==Bibliography== | |||
During his life, al-Kindi was fortunate enough to enjoy the patronage of the pro-] Caliphs ] and ], which meant he could carry out his philosophical speculations with relative ease. This would change significantly towards the end of his life when ] supported the traditionalists, and initiated persecution of various unorthodox schools of thought, including the philosophers. In his own time, al-Kindi would be criticized for extolling the "intellect" as being the most immanent creation in proximity to God, a standing commonly held to be the position only of the angels.<ref>Black, p168</ref> He also engaged in disputations with the ], whom he attacked for their belief in atoms.<ref>Black, p169</ref> 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 book, ''Incoherence of the Philosophers''.<ref>Black, p171</ref> | |||
===English translations=== | |||
==Works translated into English== | |||
* {{cite book |editor1-first=Peter |editor1-last=Adamson |editor2-first=Peter E. |editor2-last=Pormann |date=2012 |title=The Philosophical Works of al-Kindī |location=New York |publisher=Oxford University Press }} | |||
* ''The Medical Formulary of Aqra¯ba¯dhı¯n of Al-Kindi'' by M Levey (1966) | |||
* ''Al-Kindi's Metaphysics: A Translation of Yaqub ibn Ishaq al-Kindi's Treatise "On First Philosophy" (Fi al-Falsafah al-Ula)'' by Alfred L. Ivry (1974) | |||
* ''Scientific Weather Forecasting in the Middle Ages The Writings of Al-Kindi'' by Gerrit Bos and Charles Burnett (2000) | |||
* ''al-Kindi’s Treatise on Cryptanalysis'' by M. Mrayati, Y. Meer Alam and M. H. at Tayyan (2003) | |||
===Works about al-Kindi=== | |||
==Notes== | |||
* {{cite book |last=Adamson |first=Peter |title=Al-Kindī |url=https://books.google.com/books?id=KjOkI5VflygC&pg=PR11 |access-date=22 May 2011 |date=2007 |publisher=Oxford University Press US |isbn=978-0-19-518142-5 }} | |||
{{reflist|2}} | |||
* {{cite encyclopedia |last=Adamson |first=Peter|editor1-last=Adamson |editor1-first=Peter |editor2-last=Taylor |editor2-first=Richard C. |encyclopedia=The Cambridge Companion to Arabic Philosophy |date=10 January 2005 |publisher=Cambridge University Press |isbn=978-0-521-81743-1 |doi=10.1017/CCOL0521817439.003 |pages=32–51|chapter=Al-Kindī and the reception of Greek philosophy}} | |||
* {{cite book |editor-last=Arrington |editor-first=Robert L. |editor-link=Robert L. Arrington |date=2001 |title=A Companion to the Philosophers |location=Oxford |publisher=Blackwell |isbn=978-0-631-22967-4 }} | |||
==See also== | |||
* {{cite book |last=Corbin |first=Henry |author-link=Henry Corbin |date=1993 |url=https://books.google.com/books?id=UNfgAwAAQBAJ |title=History of Islamic Philosophy |location=London |publisher=Keagan Paul |isbn=9781135198886 }} | |||
*] | |||
* {{ cite encyclopedia |last=Klein-Franke |first=Felix |date=2001 |title=Al-Kindi |editor1-first=Oliver |editor1-last=Leaman |editor2-first=Hossein |editor2-last=Nasr |url=https://books.google.com/books?id=0rWhQnOOWhYC |encyclopedia=History of Islamic Philosophy |location=London |publisher=Routledge |isbn=9780415131599 }} | |||
*] | |||
*{{cite journal |last=Prioreschi |first=Plinio |url=http://www.ishim.net/ishimj/2/03.pdf |title=Al-Kindi, A Precursor of the Scientific Revolution |journal=Journal of the International Society for the History of Islamic Medicine |date=2002 |volume=2 |pages=17–19 }} | |||
*] | |||
*{{cite book |last=Prioreschi |first=Plinio |date=1996 |title=A History of Medicine: Vol.4 Byzantine and Islamic medicine |publisher=Horatius Press |location=Omaha |pages=227–235 |chapter=Medicine: al-Kindi }} | |||
==References== | |||
*] (2001) <nowiki></nowiki> ''A Companion to the Philosophers''. Oxford: Blackwell. ISBN 0-631-22967-1 | |||
*] (2004) ''One Hundred Philosophers''. New York: Barron's. ISBN 0-7641-2791-8 | |||
*Peter Adamson (2005) 'Al-Kindi'. In ] & ] (eds). ''The Cambridge Companion to Arabic Philosophy''. Cambridge: Cambridge University Press. | |||
*Peter Adamson (2006) ''Al-Kindi''. Oxford: OUP. | |||
*Felix Klein-Frank (2001) ''Al-Kindi''. In ] & ]. ''History of Islamic Philosophy''. London: Routledge. | |||
*] (1993). ''History of Islamic Philosophy''. London: Keagan Paul International. | |||
==External links== | ==External links== | ||
* {{cite SEP |url-id=al-kindi |title=Al-Kindi |last=Adamson |first=Peter}} | |||
* {{cite encyclopedia | editor = Thomas Hockey | last = Cooper | first = Glen M. | title=Kindī: Abū Yūsuf Yaʿqūb ibn Isḥāq al-Kindī | encyclopedia = The Biographical Encyclopedia of Astronomers | publisher = Springer | date = 2007 | location = New York | pages = 635–6 | url=http://islamsci.mcgill.ca/RASI/BEA/Kindi_BEA.htm | isbn=978-0-387-31022-0|display-editors=etal}} () | |||
* | |||
* {{MacTutor Biography|id=Al-Kindi|title=Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi}} | * {{MacTutor Biography|id=Al-Kindi|title=Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi}} | ||
* |
* – Famous Muslims | ||
* |
* – Islamic Philosophy Online | ||
* {{DOClink|}} – Three texts by Al Kindi in the ''Islamic Philosophy'' section | |||
* {{sep entry|al-kindi|Al-Kindi|Peter Adamson}} | |||
* with PDF extracts from the Introduction and main text | |||
* {{DOClink|}} - Three texts by Al Kindi in the ''Islamic Philosophy'' section | |||
* {{Wikisource-inline|list= | |||
** {{Cite NIE|wstitle=al-Kindi, Abu Yusuf Ya'ḳub ibn Isḥak|year=1905 |short=x |noicon=x}} | |||
** {{Cite EB1911|wstitle=Kindī |short=x |noicon=x}} | |||
** {{Cite Americana|wstitle=Kindi, Abu Yusuf Ya'kub Ibn Ishak Al- |short=x |noicon=x}} | |||
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Latest revision as of 07:07, 21 December 2024
Muslim Arab philosopher, mathematician and physician (c. 801–873) Not to be confused with Abd al-Masih ibn Ishaq al-Kindi. For the surname, see al-Kindi (surname).
al-Kindi | |
---|---|
al-Kindi on Iraqi stamp from 1962 | |
Born | c. 801 Kufa, Abbasid Caliphate |
Died | c. 873 (aged approximately 72) Baghdad, Abbasid Caliphate (now in Iraq) |
Era | Islamic Golden Age |
Region | Islamic philosophy |
School | |
Main interests | Philosophy, Islamic theology (kalam), logic, ethics, mathematics, physics, chemistry, psychology, pharmacology, medicine, metaphysics, cosmology, astrology, music theory |
Abū Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (/ælˈkɪndi/; Arabic: أبو يوسف يعقوب بن إسحاق الصبّاح الكندي; Latin: Alkindus; c. 801–873 AD) was an Arab Muslim polymath active as a philosopher, mathematician, physician, and music theorist. Al-Kindi was the first of the Islamic peripatetic philosophers, and is hailed as the "father of Arab philosophy".
Al-Kindi was born in Kufa and educated in Baghdad. He 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 Hellenistic philosophy was often referred to by Muslim scholars) had a profound effect on him, as he synthesized, adapted and promoted Hellenistic and Peripatetic philosophy in the Muslim world. He subsequently wrote hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics, logic and psychology, to medicine, pharmacology, mathematics, astronomy, astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, meteorology and earthquakes.
In the field of mathematics, al-Kindi played an important role in introducing Hindu numerals to the Islamic world, and their further development into Arabic numerals along with al-Khwarizmi which eventually was adopted by the rest of the world. Al-Kindi was also one of the fathers of cryptography. Building on the work of al-Khalil (717–786), Al-Kindi's book entitled Manuscript on Deciphering Cryptographic Messages gave rise to the birth of cryptanalysis, was the earliest known use of statistical inference, and introduced several new methods of breaking ciphers, notably frequency analysis. He was able to create a scale that would enable doctors to gauge the effectiveness of their medication by combining his knowledge of mathematics and medicine.
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 and prophetic knowledge.
Early life
Al-Kindi was born in Kufa to an aristocratic family of the Arabian tribe of the Kinda, 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. His father Ishaq was the governor of Basra 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 (r. 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 center 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 by Caliph al-Mutawakkil (r. 847–861).
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, 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 of al-Mu'tamid (r. 870–892).
After his death, al-Kindi's philosophical works quickly fell into obscurity; many were lost even to later Islamic scholars and historians. Felix Klein-Franke suggests several reasons for this: aside from the militant orthodoxy of al-Mutawakkil, the Mongols also destroyed countless libraries during their invasion of Persia and Mesopotamia. However, he says the most probable cause of this was that his writings never found popularity amongst subsequent influential philosophers such as al-Farabi and Avicenna, who ultimately overshadowed him. His philosophical career peaked under al-Mu'tasim, to whom al-Kindi dedicated his most famous work, On First Philosophy, and whose son Ahmad was tutored by al-Kindi.
Accomplishments
According to Arab bibliographer 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). Although most of his books have been lost over the centuries, a few have survived in the form of Latin translations 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.
Philosophy
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 the Abbasid Caliphs, in Baghdad. 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.
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 or speculative 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.
Astronomy
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.
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 in the treatise On Rays (De radiis) is that the planets exercise their influence in straight lines; but this treatise, written by a Latin author, probably around the middle of the 13th century, is apocryphal. In each of these, two fundamentally different views of physical interaction are presented; action by contact and action at a distance. This dichotomy is duplicated in his writings on optics.
Some of the notable astrological works by al-Kindi include:
- The Book of the Judgement of the Stars, including The Forty Chapters, on questions and elections.
- On the Stellar Rays (spurious)
- Several epistles on weather and meteorology, including De mutatione temporum, ("On the Changing of the Weather").
- Treatise 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 Planets.
Optics
Al-Kindi was the first major writer on optics since antiquity. Roger Bacon placed him in the first rank after Ptolemy as a writer on the topic. In the apocryphal work known as De radiis stellarum, is developed the theory "that everything in the world ... emits rays in every direction, which fill the whole world." This theory of the active power of rays had an influence on later scholars such as Ibn al-Haytham, Robert Grosseteste and Roger Bacon.
Two major theories of optics appear in the writings of al-Kindi: Aristotelian and Euclidean. 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. For this reason, al-Kindi considered the latter preponderant.
Al-Kindi's primary optical treatise "De aspectibus" was later translated into Latin. This work, along with Alhazen's Optics and the Arabic translations of Ptolemy and Euclid's Optics, were the main Arabic texts to affect the development of optical investigations in Europe, most notably those of Robert Grosseteste, Vitello and Roger Bacon.
Medicine
There are more than thirty treatises attributed to al-Kindi in the field of medicine, in which he was chiefly influenced by the ideas of Galen. 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 a drug, and a system (based on the phases of the moon) that would allow a doctor to determine in advance the most critical days of a patient's illness. According to Plinio Prioreschi, this was the first attempt at serious quantification in medicine.
Chemistry
Al-Kindi denied the possibility of transmuting base metals into precious metals such as gold and silver, a position that was later attacked by the Persian alchemist and physician Abu Bakr al-Razi (c. 865 – c. 925).
One work attributed to al-Kindi, variously known as the Kitāb al-Taraffuq fī l-ʿiṭr ("The Book of Gentleness on Perfume") or the Kitāb Kīmiyāʾ al-ʿiṭr wa-l-taṣʿīdāt ("The Book of the Chemistry of Perfume and Distillations"), contains one of the earliest known references to the distillation of wine. The work also describes the distillation process for extracting rose oils, and provides recipes for 107 different kinds of perfumes.
Mathematics
Al-Kindi authored works on a number of important mathematical subjects, including arithmetic, geometry, the Hindu numbers, the harmony of numbers, lines and multiplication with numbers, relative quantities, measuring proportion and time, and numerical procedures and cancellation. He also wrote four volumes, On the Use of the Hindu Numerals (Arabic: كتاب في استعمال الأعداد الهندية Kitāb fī Isti`māl al-'A`dād al-Hindīyyah) which contributed greatly to diffusion of the Hindu 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.
Cryptography
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). His book on this topic is Risāla fī Istikhrāj al-Kutub al-Mu'ammāh (رسالة في استخراج الكتب المعماة; literally: On Extracting Obscured Correspondence, more contemporarily: On Decrypting Encrypted Correspondence). In his treatise on cryptanalysis, he wrote:
One way to solve an encrypted message, if we know its language, is to find a different plaintext of the same language long enough to fill one sheet or so, and then we count the occurrences of each letter. We call the most frequently occurring letter the "first", the next most occurring letter the "second", the following most occurring letter the "third", and so on, until we account for all the different letters in the plaintext sample. Then we look at the cipher text we want to solve and we also classify its symbols. We find the most occurring symbol and change it to the form of the "first" letter of the plaintext sample, the next most common symbol is changed to the form of the "second" letter, and the following most common symbol is changed to the form of the "third" letter, and so on, until we account for all symbols of the cryptogram we want to solve.
Al-Kindi was influenced by the work of al-Khalil (717–786), who wrote the Book of Cryptographic Messages, which contains the first use of permutations and combinations to list all possible Arabic words with and without vowels.
Meteorology
In a treatise entitled as Risala fi l-Illa al-Failali l-Madd wa l-Fazr (Treatise on the Efficient Cause of the Flow and Ebb), al-Kindi presents a theory on tides which "depends on the changes which take place in bodies owing to the rise and fall of temperature." In order to support his argument, he gave a description of a scientific experiment as follows:
One can also observe by the senses... how in consequence of extreme cold air changes into water. To do this, one takes a glass bottle, fills it completely with snow, and closes its end carefully. Then one determines its weight by weighing. One places it in a container... which has previously been weighed. On the surface of the bottle the air changes into water, and appears upon it like the drops on large porous pitchers, so that a considerable amount of water gradually collects inside the container. One then weighs the bottle, the water and the container, and finds their weight greater than previously, which proves the change. Some foolish persons are of opinion that the snow exudes through the glass. This is impossible. There is no process by which water or snow can be made to pass through glass.
In explaining the natural cause of the wind, and the difference for its directions based on time and location, he wrote:
When the sun is in its northern declination northerly places will heat up and it will be cold towards the south. Then the northern air will expand in a southerly direction because of the heat due to the contraction of the southern air. Therefore most of the summer winds are merits and most of the winter winds are not.
Music theory
Al-Kindi was the first great theoretician of music in the Arab-Islamic world.Al-Kendi was the first to use musical notation, a music writing system, to write down music. He named his musical notes using literal syllables instead of letters, a process called solmization. He is known to have written fifteen treatises on music theory, but only five have survived. He added a fifth string to the 'ud. His works included discussions on the therapeutic value of music and what he regarded as "cosmological connections" of music.
Philosophical thought
Influences
While Muslim intellectuals were already acquainted with Greek philosophy (especially logic), al-Kindi is credited with being the first real Muslim philosopher. 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. 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. Experts have suggested that he was influenced by the Mutazilite school of theology, because of the mutual concern both he and they demonstrated for maintaining the singularity (tawhid) of God. A minority view however holds that such agreements are considered incidental.
Metaphysics
According to al-Kindi, the goal of metaphysics is 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.
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 one elephant", 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 theology because it implies that any description which can be predicated to anything else, cannot be said about God.
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-Platonic philosophers (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. 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. This is especially significant in the development of Islamic philosophy, as it portrayed the "first cause" and "unmoved mover" of Aristotelian philosophy as compatible with the concept of God according to Islamic revelation.
Epistemology
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.
According to Plato, everything that exists in the material world corresponds to certain universal 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 only potentially 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.
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.
The soul and the afterlife
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.
The relationship between revelation and philosophy
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.
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.
Critics and patrons
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 and logic. 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).
During his life, al-Kindi was fortunate enough to enjoy the patronage of the pro-Mutazilite Caliphs 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. He also engaged in disputations with certain Mutazilites, whom he attacked for their belief in atoms, as not all Mutazilites accepted the belief of atomism. 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.
Legacy
Al-Kindi was a master of many different areas of thought and was held to be one of the greatest philosophers. His influence in the fields of physics, mathematics, medicine, philosophy, and music were far-reaching and lasted for several centuries. Ibn al-Nadim in his Kitab al-Fihrist praised al-Kindi and his work stating:
The best man of his time, unique in his knowledge of all the ancient sciences. He is called the Philosopher of the Arabs. His books deal with different sciences, such as logic, philosophy, geometry, arithmetic, astronomy, etc. We have connected him with the natural philosophers because of his prominence in Science.
Al-Kindi's major contribution was his establishment of philosophy in the Islamic world and his efforts in trying to harmonize the philosophical investigation along with the Islamic theology and creed. The philosophical texts which were translated under his supervision would become the standard texts in the Islamic world for centuries to come, even after his influence has been eclipsed by later Philosophers.
Al-Kindi was also an important figure in medieval Europe. Several of his books got translated into Latin influencing Western authors like Robert Grosseteste and Roger Bacon. The Italian Renaissance scholar Geralomo Cardano (1501–1575) considered him one of the twelve greatest minds.
In 1986, the Royal Commission for Riyadh City inaugurated the Al Kindi Plaza in the Diplomatic Quarter district of Riyadh, Saudi Arabia.
References
- Klein-Frank, F. Al-Kindi. In Leaman, O & Nasr, H (2001). History of Islamic Philosophy. London: Routledge. p 165
- Nasr, Seyyed Hossein (2006). Islamic philosophy from its origin to the present: philosophy in the land of prophecy. State University of New York. pp. 137–138. ISBN 978-0-7914-6799-2.
- Abboud, Tony (2006). Al-Kindi: the father of Arab philosophy. Rosen. ISBN 978-1-4042-0511-6.
- Greenberg, Yudit Kornberg (2008). Encyclopedia of love in world religions. Vol. 1. ABC-CLIO. p. 405. ISBN 978-1-85109-980-1.
- "Al-Kindi biography". www-groups.dcs.st-and.ac.uk. Archived from the original on 26 October 2007.
- ^ Klein-Franke 2001, p. 165.
- ^ Corbin 1993, p. 155.
- Adamson 2005, p. 33.
- Adamson 2007, p. 7.
- ^ "Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi". Archived from the original on 26 October 2007. Retrieved 26 October 2007.
- "The man who cracked the Kama Sutra code". The Telegraph. 4 October 2000. ISSN 0307-1235. Archived from the original on 12 January 2022.
- Borda, Monica (2011). Fundamentals in Information Theory and Coding. Springer. p. 122.
Al Kindi, an Arab scientist from 9th century is considered the father of cryptology, his book on this subject being, at this moment, the oldest available.
- ^ Broemeling, Lyle D. (1 November 2011). "An Account of Early Statistical Inference in Arab Cryptology". The American Statistician. 65 (4): 255–257. doi:10.1198/tas.2011.10191. S2CID 123537702.
- Broemeling, Lyle D. (2011). "An Account of Early Statistical Inference in Arab Cryptology". The American Statistician. 65 (4): 255–257. doi:10.1198/tas.2011.10191. S2CID 123537702.
- "Al-Kindi Distinguished Statistics Lectures". Statistics at King Abdullah University of Science and Technology.
The lectures are named after Al-Kindi (801–873 CE), a prominent figure in the House of Wisdom, whose book entitled "Manuscript on Deciphering Cryptographic Messages" is believed to be the earliest writing on statistics. In his book, Al-Kindi gave a detailed description on how to decipher encrypted messages using statistics and frequency analysis. This text arguably gave rise to the birth of both statistics and cryptanalysis.
- ^ Singh, Simon (2000). The Code Book. New York City: Anchor Books. pp. 14–20. ISBN 9780385495325.
- ^ Klein-Franke 2001, p. 172.
- ^ Adamson 2005, p. 34.
- Abboud, Tony (15 January 2006). Al Kindi: The Father of Arab Philosophy. The Rosen Publishing Group, Inc. ISBN 9781404205116.
- Crone, Patricia (1980). Slaves on Horses: The Evolution of the Islamic Polity. Cambridge: Cambridge University Press. pp. 110–111. ISBN 0-521-52940-9.
- ^ Corbin 1993, p. 154.
- Klein-Franke 2001, p. 166.
- Corbin 1993, pp. 154–155.
- Klein-Franke 2001, pp. 172–173.
- Adamson 2005, p. 32-33.
- Klein-Franke 2001, pp. 166–167.
- Adamson 2005, p. 42.
- Matton, Sylvain (Winter 2023). "An Irradiation of Latin Grammarians, or The De radiis is not by al-Kindī". Magic, Ritual, and Witchcraft. 17 (3): 437–455. doi:10.1353/mrw.2023.0005. S2CID 258054985.
- Adamson 2005, p. 43.
- Dykes, Benjamin N. (2011). The Forty Chapters of Al-Kindī: Traditional Horary and Electional Astrology. Minneapolis: Cazimi Press. pp. 5–6.
- Deming, David (2012). Science and Technology in World History, Volume 2: Early Christianity, the Rise of Islam and the Middle Ages. McFarland. p. 92.
- Lindberg, David C. (1976). Theories of Vision from al-Kindi to Kepler. Chicago: University of Chicago. p. 19. OCLC 463202962.
- Lindberg, David C. (Winter 1971). "Alkindi's Critique of Euclid's Theory of Vision". Isis. 62 (4): 469–489 . doi:10.1086/350790. PMID 4948770. S2CID 40895875.
- Adamson 2005, p. 45.
- Szulakowska, Urszula (2000). The Alchemy of Light: Geometry and Optics in Late Renaissance Alchemical Illustration. Brill. p. 29.
In the West, optics was developed by fourteenth century scholastics such as Bacon, Witelo, Ockham and Pecham following Arabian models, in particular, those of Alhazen's Optics and Al-kindi's De radiis stellarum.
- Prioreschi 2002.
- Prioreschi 1996, p. 230.
- Klein-Franke 2001, pp. 173–174.
- al-Hassan, Ahmad Y. (2001). "Alchemy, chemistry and chemical technology". In al-Hassan, Ahmad Y. (ed.). Science and Technology in Islam: Technology and Applied Sciences. UNESCO. pp. 41–84. ISBN 9789231038310. pp. 65-69; al-Hassan, Ahmad Y. (2009). "Alcohol and the Distillation of Wine in Arabic Sources from the 8th Century". Studies in al-Kimya': Critical Issues in Latin and Arabic Alchemy and Chemistry. Hildesheim: Georg Olms Verlag. pp. 283–298. (same content also available on the author's website). See also Garbers, Karl (1948). Kitāb Kīmiyā' al-'Iṭr Wat-Taṣ'īdāt: Buch über die Chemie des Parfüms und die Destillationen von Ya'qūb b. Isḥāq al-Kindī. Ein Beitrag zur Geschichte der arabischen Parfümgeschichte und Drogenkunde aus de 9. Jahrh. Vol. P.C. Abhandlungen für die Kunde des Morgenlandes, 30. Leipzig: Brockhaus..
- al-Hassan 2001, p. 69.
- Al-Allaf, M. "Al-Kindi's Mathematical Metaphysics" (PDF). Archived (PDF) from the original on 7 January 2007. Retrieved 12 January 2007.
- Cozzens, Margaret; Miller, Steven J. (2013). The Mathematics of Encryption: An Elementary Introduction. American Mathematical Society. p. 5. ISBN 978-0821883211.
- Prioreschi 2002, p. 17.
- Al-Jubouri, I. M. N. (2004). History of Islamic Philosophy: With View of Greek Philosophy and Early History of Islam. Authors on Line Ltd. ISBN 9780755210114.
- Stanton, Andrea L.; Seybolt, Peter J.; Ramsamy, Edward; Elliott, Carolyn M., eds. (2012). Cultural Sociology of the Middle East, Asia, and Africa: An Encyclopedia. SAGE Publications. p. 87. ISBN 978-1412981767.
- Shehadi, Fadlou (1995). Philosophies of Music in Medieval Islam. Leiden: Brill. p. 35. ISBN 978-9004101289.
- Turner, Howard R. (28 July 2010). Science in Medieval Islam: An Illustrated Introduction (3rd pbk. print. ed.). University of Texas Press. p. 49. ISBN 978-0292781498.
- Adamson 2005, p. 37.
- ^ Adamson 2005, p. 36.
- Adamson 2005, p. 35.
- Klein-Franke 2001, p. 167.
- Adamson 2005, p. 39.
- Klein-Franke 2001, p. 168.
- Adamson 2005, pp. 40–41.
- Adamson 2005, p. 40.
- Adamson 2005, pp. 41–42.
- Adamson 2005, p. 46-47.
- Corbin 1993, p. 156.
- Adamson 2005, p. 47.
- Leaman, Oliver (1999). A Brief Introduction to Islamic Philosophy. Polity Press. p. 21. ISBN 978-0-7456-1961-3.
- Black, p168
- Black, p169
- Black, p171
- "Al-Kindi | Muslim Heritage". muslimheritage.com. 6 May 2007.
- Adamson, Peter (2018). "Al-Kindi". Al-Kindi – The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University.
- Sarton, George (1927). Introduction to the History of Science. Carnegie Institution of Washington.
Bibliography
English translations
- Adamson, Peter; Pormann, Peter E., eds. (2012). The Philosophical Works of al-Kindī. New York: Oxford University Press.
Works about al-Kindi
- Adamson, Peter (2007). Al-Kindī. Oxford University Press US. ISBN 978-0-19-518142-5. Retrieved 22 May 2011.
- Adamson, Peter (10 January 2005). "Al-Kindī and the reception of Greek philosophy". In Adamson, Peter; Taylor, Richard C. (eds.). The Cambridge Companion to Arabic Philosophy. Cambridge University Press. pp. 32–51. doi:10.1017/CCOL0521817439.003. ISBN 978-0-521-81743-1.
- Arrington, Robert L., ed. (2001). A Companion to the Philosophers. Oxford: Blackwell. ISBN 978-0-631-22967-4.
- Corbin, Henry (1993). History of Islamic Philosophy. London: Keagan Paul. ISBN 9781135198886.
- Klein-Franke, Felix (2001). "Al-Kindi". In Leaman, Oliver; Nasr, Hossein (eds.). History of Islamic Philosophy. London: Routledge. ISBN 9780415131599.
- Prioreschi, Plinio (2002). "Al-Kindi, A Precursor of the Scientific Revolution" (PDF). Journal of the International Society for the History of Islamic Medicine. 2: 17–19.
- Prioreschi, Plinio (1996). "Medicine: al-Kindi". A History of Medicine: Vol.4 Byzantine and Islamic medicine. Omaha: Horatius Press. pp. 227–235.
External links
- Adamson, Peter. "Al-Kindi". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
- Cooper, Glen M. (2007). "Kindī: Abū Yūsuf Yaʿqūb ibn Isḥāq al-Kindī". In Thomas Hockey; et al. (eds.). The Biographical Encyclopedia of Astronomers. New York: Springer. pp. 635–6. ISBN 978-0-387-31022-0. (PDF version)
- Alkindus (Bibliotheca Augustana)
- O'Connor, John J.; Robertson, Edmund F., "Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi", MacTutor History of Mathematics Archive, University of St Andrews
- Al-Kindi – Famous Muslims
- Al-Kindi's website – Islamic Philosophy Online
- Dr. Mashhad Al-Allaf DOC – Three texts by Al Kindi in the Islamic Philosophy section
- Benjamnin N. Dyke's translation of Al-Kindi's Forty Chapters with PDF extracts from the Introduction and main text
- Texts on Wikisource:
- "al-Kindi, Abu Yusuf Ya'ḳub ibn Isḥak". New International Encyclopedia. 1905.
- "Kindī". Encyclopædia Britannica (11th ed.). 1911.
- "Kindi, Abu Yusuf Ya'kub Ibn Ishak Al-". Encyclopedia Americana. 1920.
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- Philosophers of mathematics
- Philosophers of medicine
- Philosophers of psychology
- Philosophers of religion
- Philosophers of science
- Philosophers from the Abbasid Caliphate
- Mathematicians from the Abbasid Caliphate
- Physicians from the Abbasid Caliphate
- Medieval cryptographers