YAQUB IBN ISHAQ AL-KINDI (ALKINDUS) (800 – 873 C.E.)
Al-Kindi is known in the West as Alkindus. He was popularly known as the ‘Philosopher of the Arabs’ in the Middle Ages. Cardano considered Al-Kindi as one of the twelve greatest minds of the Middle Ages. He is among a small group of Muslim scientists who made original contributions in many fields. Al-Kindi was a philosopher, astronomer, physician, mathematician, physicist, and geographer. He also was an expert in music.
Yaqub Ibn Ishaq al-Kindi was born at Kufa (present Iraq) in 800 C.E. His father worked for Khalifah (Caliph) Haroon al-Rashid. Al-Kindi spent his long career in Baghdad and was a contemporary of al-Mutawakkil, al-Mamun and al-Mu’tasim. He died in 873 C.E. during the reign of al-M’utamid.
Al-Kindi was the first physician who systematically determined the dosage for most drugs. It greatly helped in the development of dosage standards (prescription) for patients. In the field of Chemistry, Al-Kindi argued that base metals cannot be converted to precious metals and that chemical reactions cannot produce transformation of basic elements. He made important contributions to the Arabic system of numerals. In addition, he contributed to spherical geometry while assisting al-Khwarizmi in astronomical studies. Al-Kindi‘s original work provided the foundation for modern arithmetic. He also made original contributions to geometrical optics, a special field of Physics, and wrote a book on it. Several centuries later, Al-Kindi‘s work inspired Roger Bacon.
Al-Kindi researched on the scientific aspects of music. He stated that the various notes that combine to produce harmony have a specific pitch, and the degree of harmony depends on the frequency of notes. Further, he provided a method for the determination of pitch. Al-Kindi stated that when a sound is produced it generates waves in the air, which strike the eardrum.
Al-Kindi wrote more than two hundred forty books. Among them are sixteen books in Astronomy, twenty-two each in Medicine and Philosophy, twelve in Physics, thirty-two in Geometry, eleven in Arithmetic, nine in Logic, four on the number system, seven in Music and five in Psychology. In addition, he wrote monographs on astronomical instruments, tides, rocks and precious stones.
Gerard of Cremona translated many of his books into Latin. These books include Ikhtiyarat al-Ayyam, al-Mosiqa, Risalah dar Tanjim, Ilahyat-e-Aristu, Mad-o-Jazr and Adviyah Murakkaba.
Al-Kindi‘s influence on the development of physics, mathematics, medicine, philosophy and music lasted for several centuries.