YAQUB IBN ISHAQ AL-KINDI (800-873 C.E.)

YAQUB IBN ISHAQ AL-KINDI 

(800-873 C.E.)

Abu Yousuf Yaqub Ibn Ishaq al-Kindi was born at Kufa around 800 C.E. His father was an official 

of Haroon al-Rashid. Al-Kindi was a contemporary of al-Mamun, al-Mu'tasim and al-Mutawakkil 

and flourished largely at Baghdad. He vas formally employed by Mutawakkil as a calligrapher. On 

account of his philosophical views, Mutawakkil was annoyed with him and confiscated all his 

books. These were, however, returned later on. He died in 873 C.E. during the reign of al-

M'utamid.

Al-Kindi was a philosopher, mathematician, physicist, astronomer, physician, geographer and even 

an expert in music. It is surprising that he made original contributions to all of these fields. On 

account of his work he became known as the philosopher of the Arabs.

In mathematics, he wrote four books on the number system and laid the foundation of a large part 

of modern arithmetic. No doubt the Arabic system of numerals was largely developed by al-

Khawarizmi, but al-Kindi also made rich contributions to it. He also contributed to spherical 

geometry to assist him in astronomical studies.

In chemistry, he opposed the idea that base metals can be converted to precious metals. In 

contrast to prevailing alchemical views, he was emphatic that chemical reactions cannot bring about 

the transformation of elements. In physics, he made rich contributions to geometrical optics and 

wrote a book on it. This book later on provided guidance and inspiration to such eminent 

scientists as Roger Bacon.

In medicine, his chief contribution comprises the fact that he was the first to systematically 

determine the doses to be adminis- tered of all the drugs known at his time. This resolved the 

conflic- ting views prevailing among physicians on the dosage that caused difficulties in writing 

recipes.

Very little was known on the scientific aspects of music in his time. He pointed out that the various 

notes that combine to produce harmony, have a specific pitch each. Thus, notes with too low or 

too high a pitch are non-pleatant. The degree of harmony depends on the frequency of notes, etc. 

He also pointed out the fact that when a sound is produced, it generates waves in the air which 

strike the ear-drum. His work contains a notation on the determination of pitch.

He was a prolific writer, the total number of books written by him was 241, the prominent among 

which were divided as follows:

Astronomy 16, Arithmetic 11, Geometry 32, Medicine 22

Physics 12, Philosophy 22, Logic 9, Psychology 5, ar,d Music 7.

In addition, various monographs written by him concern tides, astronomical instruments, rocks, 

precious stones, etc. He was also an early translator of Greek works into Arabic, but this fact has 

largely been over-shadowed by his numerous original writings. It is unfortunate that most of his 

books are no longer extant, but those existing speak very high of his standard of scholarship and

contribution. He was known as Alkindus in Latin and a large number of his books were translated 

into Latin by Gherard of Cremona. His books that were translated into Latin during the Middle 

Ages comprise Risalah dar Tanjim, Ikhtiyarat al-Ayyam, Ilahyat-e-Aristu, al-Mosiqa, Mad-o-Jazr, 

and Aduiyah Murakkaba.

Al-Kindi's influence on development of science and philosophy was significant in the revival of 

sciences in that period. In the Middle Ages, Cardano considered him as one of the twelve greatest 

minds. His works, in fact, lead to further development of various subjects for centuries, notably 

physics, mathematics, medicine and music.