Yahya ibn Adi

The Arab philosopher, theologian, and educator Abū Zakarīyā' ibn Adi (893–974) was born in what is now Iraq and became an important Christian writer and teacher during the early Islamic era in the Middle East. Also known as Yahya ibn Adi, he transmitted philosophical and scientific knowledge gleaned in the ancient world to the Arabic cultural sphere. In addition to writing out and translating many works himself, Yahya was a noted teacher of other philosophers, both Christian and Islamic.

Yahya ibn Adi, whose name can be translated as “John, son of Adi,” was born in 893 in Tikrit, in what is now Iraq. At the time, Tikrit was part of the Abbasid Caliphate, the Muslim empire of the day, ruled by descendants of the youngest uncle of the Prophet Muhammad. Tikrit also had a substantial Christian population and was a center of Christian learning. Yahya's father, Adi Ibn Hamid, may have been a bookseller; other than information about his parentage, little is known of his early life. Mentioned in various accounts over the centuries, Yahya was also referred to by longer names specifying his lineage and places of origin: Abū Zakarīyā' Ibn Adi, and even Abu Zakariyya’ Yahya Ibn ‘Adi Ibn Hamid Ibn Zakariyya’ al-Takriti al-Mantiqi, a name by which he once identified himself in writing.

Grew up in Tikrit

Yahya's family were members of the Syriac Orthodox Church, sometimes known as Jacobites. The Jacobites were one of three major branches of Eastern Christianity that often disagreed on matters of philosophy and doctrine, providing rich ground for theological debate, both among themselves and with the Islamic schools of philosophy that were growing in erudition in the area at the time. Yahya was educated in Tikrit, but between 910 and 915, seeking more rigorous studies, he moved to Baghdad. At the time, Baghdad was probably the largest city in the world and one that Tikrit could not hope to rival as a center of learning. Yahya remained there for the rest of his life, often attaching the descriptor “nazil Baghdad,” or resident of Baghdad, to his name.

In Baghdad, Yahya studied philosophy—focusing especially on logic—with two of the great minds of the age, one Christian and one Muslim. Abu Bishr Matta ibn Yunis, a Nestorian Christian (one who divided Christ's being into human and divine aspects), was renowed as a master of logic and inculcated in Yahya a lifelong bent toward close philosophical reasoning. Another influence, Abu Nasr al-Farabi, was a Muslim philosopher who was held in such high regard that he was known as the Second Teacher—the first was Aristotle, king of the Greek philosophers. Yahya may also have studied ethics, medicine, and metaphysics with the philosopher al-Razi (d. 925), as well as learning from other thinkers.

Copyist and bookseller were closely related professions in the age before the printing press, when books had to be transcribed by hand. Yahya is known to have devoted considerable time to copying manuscripts, and he boasted of his feats as a copyist. “I have transcribed with my hand two copies of the Tafsir [Quranic Commentary] of al-Tabari [d. 923], which I have taken to the kings of the frontiers, and I have copied innumerable works of the Muslim theologians. In fact, I have forced myself to write a hundred pages each day and night, though I felt this to be little,” he wrote, as quoted by Mohammed Nasir Omar in the Mediterranean Journal of Social Sciences. As can be seen, Yahya did not restrict his activities to the writings of other Christian thinkers. In addition to distributing copied books to others, he amassed a substantial library of his own.

Indeed, one of Yahya's most important activities was to translate ancient Greek philosophical writings into Arabic. He did not speak or read Greek; instead, he worked from existing translations into his native Syriac (also known today as Aramaic or Chaldean). Among the works he translated were Aristotle's six essays on logic, collectively titled the Organon, as well as a set of commentaries on those; Aristotle's Categories, Topics, Sophistical Refutations, Poetics, Physics (the second section), and one part of Meta-physics; and Plato's Laws. Although he was preceded by the Islamic philosopher Al-Kindi and other in attempting to reconcile the Greek legacy with contemporary religious developments in the Middle East, Yahya was a major conduit for Greek ideas into the Christian and Islamic worlds.

One of the major concerns of philosophers in the Arab world involved how to apply Greek reasoning to the new monotheistic faiths of the region. Could God be defined? And what of the Christian Trinity of God, the Son, and the Holy Ghost? Did this negate the idea of God as an indivisible unity? In a volume called Maqala fi at-tawhid (“Essay on Unity” ), Yahya attempted to address these questions. He asserted that, contrary to the opinions of earlier writers, God was not completely indefinable: he fell into the genus of substance, for he did not reside in anything else. Thus, he reasoned, God could be defined, and a definition was a statement, which by its very nature could have parts. There was no contradiction between the idea that God was unitary and multiple; he could be, in the words of a contributor to Islamic Philosophy online, “one in one respect and multiple in another.” Yahya identified goodness, power, and wisdom as aspects of God and related each of these to a component of the Trinity.

Islamic philosphers, of course, saw such questions differently, and Yahya seems to have engaged in dialogue with them through much of his career. One treatise by al-Kindi has disappeared and is known only through Yahya's response to it. Al-Kindi tried to disprove the idea of the Trinity through logical reasoning, pointing out that in the Christian framework, the three members of the Trinity share a common substance or essence but are differentiated by possessing a specific property. They were, thus, composite. However (as summarized by Islamic Philosophy Online), “every composite is caused, and whatever is caused cannot be eternal.” Yahya rejoined that the members of the Trinity, although indeed composite, could still be eternal “if the parts were not separate before their composition.”

Various Religions Represented among Students

The tone of such debates was collegial rather than acrimonious, as might be expected given that Yahya, a teacher, freely accepted Christians, Muslims, and Jews as students. He was also said to admire Indian philosophers. Sources of the time named al-Sijistani (d. 1001), Isa ibn Ali (d. 1001), Muhammad al-Badihi (d. 990), and Abu Hayyan al-Tawhidi (d. 1023) among Yahya's Muslim students; Christian disciples included Ibn Zura (d. 1008), Ibn al-Khammar (d. 1017), and Abu ’Ali al- Samh (d. 1027). He also had at least one Jewish follower, and one who belonged to the Sabians, an Islamic convert group. Yahya taught philosophy in Baghdad for almost 35 years, from 940 to 974, and after the departure of several other major figures, he was considered the most prestigious teacher in the city.

In addition to teaching, Yahya wrote a number of original treatises. Many of these were in the field of ethics, where he integrated Platonic and Aristotelian ideas with Christian precepts. They included practical guides such as A Treatise on the Care for Children and Their Neglect, A Discussion of Arguments for and against Celibacy (“Maqala wa-Munazara fi Hal Tark Talab al-Nasl” ), and Replies to Three Questions on Celibacy, as well as more formal philosophical works, such as A Discourse on the Management of the Soul (“Maqala fi Siyasa al-Nafs” ).

Another substantial work of ethics, The Refinement of Character (“Tahdhib al-Akhlaq” ), may or may not have been written by Yahya. He did not claim authorship of this work and he was not credited with writing it by other figures in his own time. Nevertheless, modern scholars believe that it was written by a Christian philosopher and in all likelihood by Yahya himself. The work advises moderation in the consumption of alcohol (a Muslim writer would have argued that alcohol should be prohibited), and it does not mention the Quran or the Hadith—the body of which presents accounts of the life of the Prophet Muhammad, which a Muslim writer on ethics would likely have cited. The Refinement of Character consists of several sections: an introduction (“Why Be Moral?” ) followed by “The Foundation of Ethics on the Tripartition of the Soul—The Rational, the Irascible, and the Concupiscent,” “List of Moral Virtues,” “List of Moral Vices,” “Method of the Refinement of Character: On How the Three Faculties of the Soul, Namely, the Irascible, the Concupiscent, and the Rational, Can Be Controlled by Man.”


Endress, Gerhard, The Works of Yahya Ibn Adi, Reichert, 1977.

Griffith, Sidney H., The Beginnings of Christian Theology in Arabic: Muslim-Christian Encounters in the Early Islamic Period, Ashgate, 2002.

Rescher, Nicholas, Studies in Arabic Philosophy, University of Pittsburgh Press, 1968.


Mediterranean Journal of Social Sciences, April 2015, p. 308.


“Ibn ’Adi, Yahya (893–974), Islamic Philosophy Online, http://www.muslimphilosophy.com/ip/rep/H034 (January 6, 2017).❑

(MLA 8th Edition)