Al-Kindi was the first genuine philosopher to write in Arabic. He was a universal scholar who wrote over 200 texts about mathematics, astronomy, optics, medicine, music and psychology. In addition he worked as a chemist, optician, and music theorist.

Writing of chemistry, Al-Kindi argued that base metals cannot be converted to precious metals.

He also researched on the scientific aspects of music. He stated that the various notes that combine to produce harmony have a specific pitch, and he stated that when a sound is produced it generates waves in the air.

He made important contributions to the Arabic system of numerals. His original work provided the foundation for modern arithmetic.